WO2018164108A1 - Light guide device - Google Patents

Light guide device Download PDF

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Publication number
WO2018164108A1
WO2018164108A1 PCT/JP2018/008532 JP2018008532W WO2018164108A1 WO 2018164108 A1 WO2018164108 A1 WO 2018164108A1 JP 2018008532 W JP2018008532 W JP 2018008532W WO 2018164108 A1 WO2018164108 A1 WO 2018164108A1
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WO
WIPO (PCT)
Prior art keywords
light
light guide
groove
degrees
guide plate
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Application number
PCT/JP2018/008532
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French (fr)
Japanese (ja)
Inventor
誠二 木下
Original Assignee
株式会社クラレ
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Publication date
Application filed by 株式会社クラレ filed Critical 株式会社クラレ
Publication of WO2018164108A1 publication Critical patent/WO2018164108A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S2/00—Systems of lighting devices, not provided for in main groups F21S4/00 - F21S10/00 or F21S19/00, e.g. of modular construction
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings

Definitions

  • the present invention relates to a light guide device.
  • Patent Document 1 describes a light guide device used in an edge light type illumination device.
  • a light guide device includes a light guide plate and a reflection sheet.
  • One of the main surfaces of the light guide plate is an emission surface.
  • a lenticular lens parallel to the light guide direction is provided on the exit surface.
  • a V-shaped groove orthogonal to the light guide direction is provided on the other surface of the main surfaces of the light guide plate.
  • the side surface of the light guide plate is an incident end surface. Light incident on the light guide plate from the incident end face is reflected by the V-shaped groove and the reflection sheet. The light further exits from the exit surface through the lenticular lens.
  • An object of the present invention is a light guide device including a light guide plate, which diffuses light incident from the side of the light guide plate in the light guide device and emits light using the main surface of the light guide plate as an output surface. Is to provide a device.
  • the exit surface method when the light is incident on the incident end face of the light guide plate and the exit surface of the light guide plate faces the irradiated surface that is irradiated with light from the exit surface, the exit surface method is used. It is an object to obtain an illuminance distribution that is bright in a direction at a low angle, approximately 20 to 30 degrees with respect to the line direction, and smoothly changes to a direction at a high angle, approximately 60 to 70 degrees.
  • a light guide device comprising a light guide plate and a reflective sheet
  • the light guide plate has an incident end surface having a light receiving surface, a lower bottom surface having a deflection surface, and an upper bottom surface having an internal reflection surface
  • the reflective sheet faces the internal reflective surface
  • the deflection surface has a plurality of grooves parallel to each other and narrowing according to the depth, The grooves are sequentially arranged in the direction from the vicinity of the light receiving surface toward the far side of the light receiving surface (hereinafter referred to as the light guide direction), and meandering smoothly when the light guide plate is viewed in plan view
  • the upper bottom surface is a ridge provided on the internal reflection surface, and has a ridge that is parallel to each other and extends in a direction along the light guide direction, In a cross section parallel to the normal line of the light receiving surface and the normal line of the reference plane in which the light guide plate extends, the average slope of the side of the contour line of the groove with respect to the reference plane is 12 on the light receiving surface side.
  • the deflection surface functions as a light emitting surface that emits light to a side far from the light receiving surface.
  • Light guide device When light is incident on the incident end face of the light guide plate from a light source, A part of the incident light is diffused by being reflected by the groove, is further reflected by the internal reflection surface and is diffused by the ridge, and is further emitted from the deflection surface, Further, the other part of the incident light exits without being reflected by the internal reflection surface, and further re-enters the light guide plate from the internal reflection surface by being reflected by the reflection sheet. Emanating from the deflection surface, Thus, the deflection surface functions as the light emitting surface. [1] The light guide device.
  • the average slope of the side portion of the groove contour line is 13.5 degrees to 17.5 degrees.
  • the light guide device according to [1] or [2].
  • the outline of the groove is a symmetrical trapezoid or triangle, If the contour line of the groove is trapezoidal, the width of the deepest part of the contour line is 1 to 250 ⁇ m, The depth of the groove is 2 to 100 ⁇ m. [1] to [3].
  • the inclination angle formed by the tangent line of the contour line of the groove with respect to the reference plane monotonously decreases as the depth in the groove increases, and depends on the depth in the groove. Change smoothly [4] The light guide device.
  • the meandering phases of the grooves coincide with each other among the plurality of grooves, With respect to the meandering valley of the groove, beyond the center of the amplitude of the meandering of the groove, the meandering mountain of another adjacent groove enters.
  • the light guide device according to any one of [1] to [5].
  • the outline of the ridge in the cross section of the ridge consists of a smoothly curved arc, elliptical arc, or parabola, In the base of the ridge, the angle formed by the contour line of the ridge with respect to the reference plane is 60 degrees or less.
  • the light guide device according to any one of [1] to [6].
  • the deflection surface is located in the center of the lower bottom surface, The lower bottom surface has a smooth surface surrounding the deflection surface;
  • the light guide device according to any one of [1] to [7].
  • a planar light emitting module comprising the light guide device according to any one of [1] to [8] and a point light source group, wherein the light receiving surface faces the point light source group,
  • the point light source group includes a plurality of point light sources arranged in rows at predetermined intervals in a direction parallel to the deflection surface. Planar light emitting module.
  • Two point light source groups are provided, where the point light source groups are referred to as first and second point light source groups,
  • the light guide plate has two incident end surfaces, and each incident end surface has first and second light receiving surfaces facing each other across the deflection surface as the light receiving surfaces, respectively.
  • the first and second light-receiving surfaces are opposed to the first and second point light source groups, respectively.
  • the deflecting surface emits the light of the first point light source group toward the second light receiving surface side, and emits the light of the second point light source group to the first light receiving surface side.
  • the planar light emitting module according to [9].
  • a diffusion plate that opposes the lower bottom surface of the light guide plate and scatters light emitted from the deflection surface, or transmits light emitted from the deflection surface while facing the lower bottom surface of the light guide plate. Further having a transparent protective plate, The planar light emitting module according to [9] or [10].
  • the exit surface of the light guide plate provided in the light guide device faces the irradiated surface, it changes brightly in a low angle direction with respect to the normal direction of the exit surface and smoothly changes to a high angle direction. Illuminance distribution can be obtained.
  • FIG. 6 is a plan view of a light receiving surface viewed from the ⁇ Z direction. It is an end elevation showing the outline of a groove in a section. It is sectional drawing of a protruding item
  • Example 10 is a light distribution graph of the light guide device of Comparative Example 2. It is a light distribution graph of the comparative example 3 whose average inclination of a groove
  • FIG. 20 is a schematic diagram of a cross section of a light guide device in Example 18. 22 is a light distribution graph of Example 18. It is a front view of the planar light emitting module of Example 19.
  • light spreading means that light is diffused by an optical element whose three-dimensional dimensions are designed on a macroscopic scale. However, it is not intended that all optical paths that light can take within an optical element are fully predicted. Light diffusion is confirmed by experiments such as measurement of light distribution characteristics. Unless otherwise stated, the light spreading in this embodiment is distinguished from the accidental diffusion of light, which is the result of light irregular reflection or light scattering by fine particles or rough surfaces.
  • the optical element for spreading of light according to the present embodiment and the optical element for scattering or irregular reflection of light used in the present embodiment are combined to affect light, the result is as follows: And light spreading.
  • FIG. 1 shows a light guide device 40 according to this embodiment.
  • the light guide device 40 includes a light guide plate 45 and a reflection sheet 50.
  • the light guide plate 45 extends on the reference plane Ps. In the drawing, the reference plane Ps is parallel to the XY plane.
  • the light guide plate 45 includes a lower bottom surface having a deflection surface 41 and an upper bottom surface having an internal reflection surface 42. In the drawing, the deflection surface 41 and the internal reflection surface 42 extend along the XY plane.
  • the upper bottom surface is the other main surface of the light guide plate 45.
  • a part of the side surface is an end surface 43a having a light receiving surface.
  • the end surface 43a functions as an incident side surface.
  • the end face 43a in the drawing is parallel to the XZ plane.
  • FIG. 1 shows a cross section 44 of the light guide plate 45.
  • the cross section 44 is parallel to the normal line of the reference plane Ps and the normal line of the light receiving surface formed by the end face 43a. In the drawing, the cross section 44 is parallel to the YZ plane.
  • the incident direction In is preferably perpendicular to the light receiving surface formed by the end face 43a. In the figure, the incident direction In is parallel to the Y axis.
  • the light that has entered the light guide plate 45 from the light receiving surface formed by the end face 43a shown in FIG. 1 is guided along the light guide direction Gu.
  • the light guide direction Gu is parallel to the reference plane Ps.
  • the light guide direction Gu is parallel to the normal line of the light receiving surface formed by the end face 43a.
  • the light guide direction Gu is parallel to the cross section 44.
  • the light guide direction Gu is parallel to the Y axis.
  • the deflection surface 41 shown in FIG. 1 emits the guided light toward the emission direction Ex1.
  • the emission direction Ex1 is a direction toward the far side from the light receiving surface formed by the end face 43a. In this way, the deflection surface 41 functions as a light emitting surface.
  • An optical model for using the deflection surface 41 as a light emitting surface will be described later.
  • the end surface 43b faces the end surface 43a across the central portion of the light guide plate 45.
  • the end surface 43b may also be an incident end surface by having a light receiving surface. Such an embodiment will be described in Examples.
  • the reflective sheet 50 shown in FIG. 1 covers part or all of the internal reflective surface 42.
  • the reflection sheet 50 has a reflection surface 49.
  • the reflection surface 49 faces the internal reflection surface 42.
  • the reflective surface 49 may be in contact with the internal reflective surface 42 or may not be in contact therewith.
  • the diffuse reflectance of the reflecting surface 49 is preferably 90% or more.
  • the diffuse reflectance is a variable related to light diffused by irregular reflection.
  • the diffuse reflectance is defined as follows. Usually, the reflectance is measured by measuring the light reflected by the sample when the sample is irradiated with light. The reflected light includes specular reflection light and diffuse reflection light. A combination of these is called total light reflected light.
  • the total light reflectance is the reflectance of the total light reflected light.
  • Total light reflectance is the ratio of the amount of light reflected by the sample to the amount of light incident on the sample.
  • the diffuse reflectance is the ratio of the amount of diffusely reflected light to the amount of light incident on the sample.
  • the amount of diffusely reflected light is obtained by subtracting the amount of specularly reflected light from the amount of total reflected light. Since it is difficult to selectively measure the amount of diffuse reflection light, the diffuse reflectance is calculated in this way for convenience.
  • the deflection surface 41 shown in FIG. 1 has grooves 47a-d.
  • the deflecting surface 41 exhibits a function of deflecting light by the groove.
  • the depth in the grooves increases in the + Z-axis direction.
  • the grooves 47a-d are grooves that become narrow according to the depth in the grooves 47a-d.
  • FIG. 2 shows the deflection surface 41 as viewed from the -Z direction in FIG.
  • the grooves 47a-d are represented by a baseline representing the center of the groove.
  • the grooves 47a-d are parallel to each other.
  • the grooves 47a-d are sequentially arranged in the direction from the vicinity of the light receiving surface formed by the end face 43a to the far side of the light receiving surface. Such a direction coincides with the light guide direction Gu.
  • the grooves 47a-d extend in a direction crossing the light traveling along the light guide direction Gu. In the present embodiment, such a direction may be referred to as a longitudinal direction.
  • the shape of the meandering baseline of the grooves 47a-d shown in FIG. 2 may be a sine curve or a parabola. In the drawing, the line representing the edge of the groove is omitted. In the figure, grooves other than the grooves 47a-d are also shown. Grooves having the same shape as the grooves 47a-d may be further increased or decreased along the light guide direction Gu. The number of grooves can be designed as appropriate.
  • the grooves 47a-d meander smoothly.
  • the meandering phases may match between the grooves 47a-d and may be irregularly shifted from each other. In the figure, the phases of meandering are the same.
  • the distance between the base lines of adjacent grooves is preferably 0.02 to 2 mm, and more preferably 0.05 to 1.0 mm.
  • the term of the meandering amplitude center may represent the meandering vibration center.
  • the centers 46a-d are parallel to each other.
  • the center 46a-d is parallel to the end face 43a. In the figure, the center 46a-d is parallel to the X-axis direction.
  • the grooves 47a-d preferably do not cross each other.
  • the meandering mountain 48b of another adjacent groove 47b enters the meandering valley 48a of the base line of the groove 47a shown in FIG.
  • the meandering mountain 48b preferably further exceeds the center 46a which is the center of the meandering amplitude of the groove 47a.
  • the unit length Ul of the meandering of the baseline of the grooves 47a-d shown in FIG. 2 is the so-called meandering wavelength. In the grooves 47a-d, meandering for the unit length Ul is repeated.
  • the unit length Ul is preferably 3 mm or less, and more preferably 1 mm or less.
  • the maximum value of the baseline displacement from the center 46a-d is taken as the amplitude.
  • the amplitude is preferably 1 mm or less, and more preferably 600 ⁇ m or less.
  • the ratio represented by (amplitude) / (unit length Ul) may be referred to as ⁇ value.
  • ⁇ value When the unit length Ul is 0.5 mm and the amplitude is 70 ⁇ m (0.07 mm), the ⁇ value is 0.14.
  • the ⁇ value is preferably 0.12 or more. If it is smaller than this, it will be difficult to smoothly change the illumination surface illumination distribution.
  • FIG. 3 shows the outline of the groove 47a in the cross section 44 shown in FIG.
  • the upper base Bu represents the deepest portion of the groove 47a.
  • the width of the upper base Bu can be designed as appropriate.
  • the width of the upper base Bu may be zero. That is, the groove 47a may be a V-shaped groove in which the deepest portion of the groove 47a is angular.
  • the lower base Bl represents the opening of the groove 47a.
  • the width of the lower base Bl can be designed as appropriate.
  • the depth Dp represents the distance between the upper base Bu and the lower base Bl. That is, the depth Dp represents the entire depth of the groove 47a.
  • the depth Dp is preferably 2 to 100 ⁇ m, more preferably 4 to 15 ⁇ m.
  • the side parts La1 and La2 represent the slope of the groove 47a.
  • the outline may be a trapezoid made up of the upper base Bu, the lower base Bl, and the side portions La1 and La2 forming the legs.
  • the trapezoid may be a symmetrical trapezoid, that is, an isosceles trapezoid.
  • the width of the upper base Bu is preferably 1 to 250 ⁇ m, more preferably 1 to 5 ⁇ m.
  • the outline may be a triangle composed of the lower base Bl and the side portions La1 and La2.
  • the triangle may be a symmetrical triangle, that is, an isosceles triangle with the lower base B1 as the base.
  • the limitation that the contour line forms a trapezoid or a triangle does not mean that the contour line is limited to a shape in which the upper base Bu and the side portions La1 and La2 are strictly formed by straight lines. . That is, the side portions La1 and La2 may be configured with a curve including an example described later.
  • the upper base Bu may also be configured with a curve.
  • the trapezoid may be replaced with a figure in which the legs formed on the sides of the trapezoid are replaced with curves.
  • the triangle may be replaced with a figure in which the side formed by the side of the triangle is replaced with a curve.
  • the average slopes of the side portions La1 and La2 with respect to the reference plane Ps are represented as slopes Ob1 and Ob2.
  • the slope Ob1 is the slope on the slope in the light guide direction, that is, the slope closer to the light receiving surface among the slopes of the groove 47a.
  • the slope Ob2 is a slope on the slope in the light guide direction, that is, the slope far from the light receiving surface among the slopes of the groove 47a.
  • the angle formed by the cross section 44 and the groove 47a is not necessarily 90 degrees. Therefore, the contour line may proceed so as to cross the slope of the groove 47a obliquely. Therefore, the slopes Ob1 and Ob2 shown in FIG. 3 do not necessarily coincide with the so-called maximum slope of the slope of the groove 47a.
  • the inclination Ob2 is an angle formed by a reference plane Ps and a line segment connecting the intersection of the side portion La2 and the lower base B1, and the intersection of the side portion La2 and the upper base Bu. The same applies to the case where the side portions La1 and La2 are formed of curves.
  • the slope Ob1 shown in FIG. 3 is preferably 12.5 degrees to 20 degrees, more preferably 13.5 degrees to 17.5 degrees.
  • the inclination Ob2 is preferably 12.5 degrees to 20 degrees, more preferably 13.5 degrees to 17.5 degrees.
  • the slope Ob2 is preferably equal to the slope Ob1.
  • the vertex angle V is preferably 140 to 155 degrees, and more preferably 145 to 153 degrees.
  • the side portions La1 and La2 shown in FIG. 3 may be replaced with side portions La3 and 4 each formed of a curve.
  • the side parts La3 and La4 are curved so that the inclination becomes larger as they are closer to the lower base Bl.
  • the inclination angle formed by the tangent line of the side portion La3 and the tangent line of the side portion La4 with respect to the reference plane decreases monotonously as the depth in the groove increases, and is smooth according to the depth in the groove. To change.
  • the angle formed between the tangent line of the side portion La3 and the tangent line of the side portion La4 and the reference plane Ps shown in FIG. 3 changes smoothly in the range of 5 degrees to 25 degrees, preferably 10 degrees to 20 degrees.
  • the opening angle of the tangent line of the side portion La3 and the tangent line of the side portion La4 when viewed from the lower bottom Bl side shown in FIG. In such a curved groove, the apex angle V changes depending on the depth in the groove 47a.
  • a contour line having a curve as shown in the side portions La3 and La4 shown in FIG. 3 can be designed by a spline curve, for example.
  • the slopes of the side portions La3 and 4 are also equal to the slopes Ob1 and Ob2.
  • grooves than the groove 47a have the same contour line as the groove 47a in the cross section 44.
  • the cross-sectional shape of such a groove is preferably the same at any location when it travels along the center of the groove.
  • the cross-sectional shape of the groove is preferably the same in any X coordinate.
  • a plurality of ridges including ridges 51 are provided on the internal reflection surface 42 shown in FIG. These ridges are parallel to each other.
  • a plane parallel to the reference plane Ps may be provided between the parallel ridges. Such a plane may be a smooth surface.
  • the protrusion 51 may be formed integrally with the central portion of the light guide plate 45. What was attached as a separate body with respect to the center part of the light-guide plate 45 may be used.
  • the central axis of the ridge 51 is preferably a straight line.
  • These ridges including the ridge 51 shown in FIG. 1 extend in a direction along the light guide direction Gu.
  • the ridge 51 is preferably perpendicular to the light receiving surface formed by the end surfaces 43a and 43b.
  • the ridge 51 can be a straight line parallel to the normal line of the light receiving surface. In the figure, the ridges 51 are parallel to the Y axis.
  • the 1 can have a height of 10 to 500 ⁇ m, preferably 10 to 50 ⁇ m.
  • the height of the ridges 51 may not be constant.
  • the center-to-center distance between the ridges can be 50 to 300 ⁇ m.
  • the thickness of the light guide plate 45 including the height of the ridges 51 is preferably 1 to 4 mm, and more preferably 2 to 3 mm.
  • the outline of the ridge 51 in a cross section perpendicular to the central axis of the ridge 51 shown in FIG. 1 may be an elliptical arc, an arc, a parabola, or a polygon.
  • the arc may be a semicircle. It is preferable that the ridge is smoothly curved.
  • the ridge 51 is a lenticular lens formed of an arc
  • the aspect ratio of the ridge 51 will be described with reference to the cross-sectional view of FIG.
  • the radius of the arc 52 forming the lenticular lens in the vertical section of the lenticular lens formed by the ridges 51 is represented by Ra. Further, the distance from the apex of the arc 52 to the string, that is, a positive arrow (versed sine) is set as Vs. At this time, the aspect ratio is represented by the formula: (Vs / 2Ra) ⁇ 100 (%).
  • the aspect ratio of the ridges 51 shown in FIG. 4 can be greater than 0% and 30% or less.
  • the aspect ratio is preferably 20%.
  • the angle formed by the tangent line with respect to the reference plane Ps at an arbitrary point on the arc 52 can be 0 to 85 degrees, preferably 0 to 70 degrees.
  • the angle formed by the tangent to the contour line of the ridge in the section of the ridge represents the angle with respect to the reference plane.
  • the angle An shown in FIG. 4 is an angle formed by a tangent to the contour line of the ridge 51 at the base of the ridge 51 with respect to a plane parallel to the reference plane Ps.
  • the angle An is preferably 60 degrees or less. If the aspect ratio is 20%, the angle An is 53.1 degrees.
  • FIG. 5 is an end view showing a cross section of the light guide device 40.
  • the front-rear direction is opposite to that in FIG.
  • An optical model for using the deflection surface 41 as a light emitting surface will be described below with reference to FIG.
  • a light beam 57 a that is part of the incident light travels through the light guide plate 45.
  • the light beam 57 a is reflected by a groove 47 a provided on the deflection surface 41. Since the groove 47a meanders, the light beam 57a is diffused by the groove 47a. Further, the light beam 57 a is reflected again by the internal reflection surface 42. The light rays 57a are further diffused by the ridges provided on the internal reflection surface.
  • the light beam 57a returns to the deflecting surface 41 again.
  • the light beam 57a is emitted from the deflecting surface 41 toward the outside.
  • the groove 47c through which the light beam 57a passes is inclined, it is reduced that the light beam 57a is totally reflected by the deflecting surface 41 and returns to the center of the light guide plate 45 again.
  • the light beam 57a travels in a direction at a high angle, approximately 60 to 70 degrees, with respect to the normal direction of the exit surface. In the figure, it proceeds in the direction of 60 to 70 degrees with respect to the ⁇ Z direction.
  • the light beam 57 b which is another part of the incident light travels in the light guide plate 45.
  • the light beam 57 b is emitted from the internal reflection surface 42 without being reflected by the internal reflection surface 42.
  • the light beam 57 b is further reflected by the reflection surface 49 of the reflection sheet 50.
  • the reflection surface 49 may have a predetermined diffuse reflectance so that the light beam 57b is irregularly reflected.
  • the light beam 57 b is incident on the internal reflection surface 42.
  • the light beam 57 b reenters the light guide plate 45.
  • the light beam 57b is emitted from the deflecting surface 41 toward the outside.
  • the light beam 57a travels at a low angle with respect to the normal direction of the exit surface, generally in the direction of 20 to 30 degrees. In the figure, it proceeds in the direction of 20 to 30 degrees with respect to the -Z direction.
  • the light guide device 40 shown in FIG. 5 may further include a diffusion plate 55 for scattering light.
  • the diffusion plate 55 is opposed to the lower bottom surface having the deflection surface 41.
  • the diffuser plate 55 scatters light including light rays 57 a and b emitted from the deflection surface 41.
  • the front and back surfaces of the diffusing plate 55 shown in FIG. 5 can be mirror surfaces or textured surfaces, and are not particularly limited.
  • the total light transmittance (T.T) of the diffusion plate 55 is preferably 90% or more.
  • the haze value (Haze) is preferably 70% or more.
  • the diffusion plate 55 may function as a protection plate.
  • the thickness of the diffusion plate 55 or the protection plate is preferably 0.1 to 3 mm.
  • the light guide device 40 has a desired light distribution characteristic based on at least the shape design of the optical element shown in FIGS. Demonstrate. In the first part of the following examples, the relationship between these optical elements and the light distribution characteristics will be described.
  • a smooth illuminance distribution change can be realized by the light distribution characteristics.
  • the relationship between the optical element and the change in illuminance distribution will be described.
  • FIG. 5 described above is a model and does not represent all light paths. Therefore, considering the presence of light partially reflected by the deflecting surface 41 and other light, the light distribution characteristics and the illuminance distribution change described above are realized by the light following various paths not shown in FIG. It is easily expected to be.
  • a predetermined light guide plate was first prepared.
  • a light guide device was obtained by covering the internal reflection surface or the deflection surface of the light guide plate with a reflection sheet as necessary.
  • the planar light emitting module was obtained by combining the light guide device and the point light source group. Optical measurement was performed on the planar light emitting module.
  • FIG. 6 shows the planar light emitting module 70 of the first embodiment.
  • the optical elements included in the planar light emitting module 70 will be described below.
  • the planar light emitting module 70 includes a light guide device 60 including a light guide plate 65 and a reflection sheet 50.
  • a lower bottom surface 61 of the light guide plate 65 is shown.
  • the reflection sheet 50 is installed on the back side of the lower bottom surface 61.
  • the reflection surface of the reflection sheet 50 has a diffuse reflectance of 90% or more.
  • the reflection sheet 50 is a diffusion type reflection sheet.
  • the lower bottom surface 61 has a deflection surface 41.
  • the light guide plate 65 shown in FIG. 6 has the same configuration as the light guide plate 45 shown in FIG.
  • the light guide plate 65 further has the following characteristics.
  • the deflection surface 41 is located at the center of the lower bottom surface 61.
  • the lower bottom surface 61 has a smooth surface 63 surrounding the deflection surface 41.
  • a smooth surface 63 is located between the end surface 43 a and the deflection surface 41.
  • the light guide plate 65 further has an upper bottom surface behind the lower bottom surface 61.
  • the upper bottom surface is not shown in the drawing.
  • the upper bottom surface may have an internal reflection surface surrounded by a smooth surface. In the examples and comparative examples, there is no smooth surface between the end surface 43a and the internal reflection surface and between the end surface 43b and the internal reflection surface. That is, it has an internal reflection surface from the end surface 43a to the end surface 43b.
  • the planar light emitting module 70 shown in FIG. 6 further includes a point light source group 66.
  • An end face 43 a forming a light receiving surface faces the point light source group 66.
  • the point light source group 66 has a plurality of point light sources arranged in rows at predetermined intervals. The number of point light sources is not limited.
  • the point light source is preferably an LED. In this embodiment, a white LED is used as a point light source.
  • the direction of the row formed by the point light sources is parallel to the deflection surface 41.
  • channel provided in the deflection surface with which the light-guide plate of Example 1 is provided is demonstrated referring FIG.
  • the unit length Ul of the meandering of the groove base line is 0.5 mm.
  • the amplitude of the meandering of the groove baseline is 70 ⁇ m (0.07 mm).
  • the ⁇ value is 0.14.
  • the spacing between the groove baselines is 62 ⁇ m.
  • 662 grooves are provided without gaps. The phases of the grooves are the same.
  • the width of the upper base Bu is 0 ⁇ m. That is, the outline of the cross section of the groove is a triangle.
  • the width of the lower base Bl is 55 ⁇ m.
  • the depth Dp is 7 ⁇ m. Both the slope Ob1 and the slope Ob2 are equal. That is, the outline of the cross section of the groove is an isosceles triangle. These angles are 15 degrees.
  • the apex angle V is 150 degrees.
  • the side portions of the groove are linear as shown by the side portions La1 and La2.
  • the contour of the cross section of the ridge is an arc.
  • the ridge is a lenticular lens.
  • a ridge having a circular cross-sectional outline may be particularly referred to as a lenticular.
  • the aspect ratio is 20%.
  • the height of the ridge is 12.5 ⁇ m.
  • the planar light emitting module 70 further includes a reflector 67.
  • the reflective material 67 is a member having a different direction from the reflective sheet 50.
  • the reflective surface of the reflective material 67 faces the end surface 43b. The light is irregularly reflected on the reflecting surface of the reflector 67.
  • the point light source group 66 shown in FIG. 6 was turned on, and the light distribution characteristics of the planar light emitting module of Example 1 were measured. The results are shown in FIGS. The mode of measuring the light distribution characteristics is the same in the other examples and comparative examples.
  • FIG. 7 shows a gonio map of the planar light emitting module of Example 1.
  • a gonio map is sometimes called an isoluminous graph.
  • the X axis and the Y axis correspond to the X axis and the Y axis shown in FIG.
  • the upper part of the gonio map corresponds to the emission direction Ex1 shown in FIG.
  • the 0 degree at the center represents the luminous intensity in the ⁇ Z direction shown in FIG.
  • G 7 represent regions where the level of luminous intensity (cd) per 1,000 ⁇ m of luminous flux is equal.
  • the range of luminous intensity in each region is as follows. G1 (0.0-67.5), G2 (67.5-135.0), G3 (135.0-202.5), G4 (202.5-270.0), G5 (270.0-337.5), G6 (337.5-405.0), G7 (405.0-472.5), G8 (472.5-540.0).
  • FIG. 8 shows a light distribution graph of the planar light emitting module of Example 1.
  • the 0 degree at the center represents the luminous intensity in the ⁇ Z direction shown in FIG.
  • ⁇ 90 degrees represents the ⁇ X direction shown in FIG. 1
  • +90 degrees represents the + X direction shown in FIG.
  • the light distribution curve Dy ⁇ 90 degrees represents the ⁇ Y direction shown in FIG. 1
  • 90 degrees represents the + Y direction shown in FIG.
  • the way to read the graph is the same below.
  • Example 7 and 8 show that the light emitted from the planar light emitting module of Example 1 is biased in the + Y direction. It can also be seen that the light intensity around 60-70 degrees in the + Y direction is the strongest. It can also be seen that the luminous intensity changes gradually from around 0 degrees to around 60-70 degrees. It can also be seen that light diffuses gently in the +/ ⁇ X direction.
  • Comparative Example 1 shown in FIG. 9 a light guide plate equivalent to the light guide plate 65 used in Example 1 was used. However, the reflection sheet 50 facing the internal reflection surface 42 was not used. In the light guide plate 65 in the drawing, the drawing of the smooth surface around the deflection surface 41 and the internal reflection surface 42 is omitted for convenience of explanation.
  • the reflective material 67 was used.
  • the light beams 58a to 58c shown in FIG. 9 schematically represent a light beam derived from a point light source.
  • the light represented by the light beams 58a to 58c is guided along the light guide direction Gu.
  • the direction of the light is changed by the action of the deflection surface 41.
  • a part of the light is reflected by the internal reflection surface 42 and then emitted from the deflection surface 41 along the emission direction Ex2.
  • Ex2 represents all directions in the emission direction on the deflection surface 41 side.
  • the emission direction Bc1 represents all directions among the emission directions on the internal reflection surface 42 side.
  • the luminous flux on the emission direction Ex2 side and the luminous flux on the emission direction Bc1 side are compared, the luminous flux on the emission direction Bc1 side is larger.
  • Example 1 by providing the reflection sheet 50 as shown in FIG. 9, the light emitted from the internal reflection surface 42 is reflected by the reflection surface of the reflection sheet 50. Thereby, a lot of light can be emitted from the deflection surface 41 side.
  • FIG. 9 is a reflective sheet equivalent to the reflective sheet 50.
  • Comparative Example 2 a light guide device in which the reflection sheet is arranged on the deflection surface side in this way was used. Thereby, the light emitted from the deflection surface side is reflected by the reflection sheet, reenters the light guide plate from the deflection surface, and exits from the internal reflection surface 42 side.
  • FIG. 10 shows the light guide device 75 of the second comparative example.
  • the light guide device 75 of the comparative example 2 has a deflection surface 71 instead of the deflection surface 41 (FIG. 1).
  • the deflection surface 71 includes linear grooves 77a-d.
  • the light guide device 75 does not include a reflection sheet provided on the internal reflection surface 42 side.
  • the light guide device 75 includes a reflection sheet 68 provided on the deflection surface side.
  • Other features are the same as those of the light guide device of the first embodiment.
  • the light guided in the light guide plate 45 is emitted along the emission direction Bc2.
  • the emission direction Bc2 is a direction toward the side far from the light receiving surface formed by the end face 43a.
  • Comparative Example 2 a planar light emitting module was produced in the same manner as in Example 1 using the light guide device 75 shown in FIG. The light distribution characteristics of the planar light emitting module of Comparative Example 2 were measured.
  • FIG. 11 shows a light distribution graph of the planar light emitting module of Comparative Example 2. It can be seen that the light emitted from the planar light emitting module of Comparative Example 2 is also biased in the + Y direction. However, the light intensity in the vicinity of 40-60 degrees inclined from the + Z direction on the + Y direction side was the strongest. It can also be seen that the luminous intensity is weak at around 0 to 20 degrees, but the luminous intensity increases rapidly from around 30 degrees. The light diffused gently in the +/ ⁇ X direction.
  • planar light emitting module depend on the average slope or apex angle V of the groove. As described below, planar light emitting modules having different average slopes of the grooves were prepared, and their light emission characteristics were measured.
  • FIG. 12 shows a light distribution graph of the planar light emitting module of Comparative Example 3.
  • the average inclination of the grooves is 25 degrees.
  • the apex angle V is 130 degrees.
  • the spacing between the groove baselines is 40 ⁇ m.
  • the light intensity decreased in the vicinity of 60 ° tilted to the + Y direction side from the + Z direction. For this reason, unlike Example 1, two remarkable light intensity peaks were formed.
  • FIG. 13 shows a light distribution graph of the planar light emitting module of Comparative Example 4.
  • the average slope of the grooves is 22.5 degrees.
  • the apex angle V is 135 degrees.
  • the spacing between the groove baselines is 45 ⁇ m.
  • the light intensity decreased in the vicinity of 60 ° tilted to the + Y direction side from the + Z direction. For this reason, unlike Example 1, two remarkable light intensity peaks were formed.
  • FIG. 14 shows a light distribution graph of the planar light emitting module of Example 2.
  • the average slope of the grooves is 20 degrees.
  • the apex angle V is 140 degrees.
  • the spacing between the groove baselines is 50 ⁇ m. It can be seen that the light intensity slightly decreased in the vicinity of 60 ° tilted to the + Y direction side from the + Z direction, but gradually changes to 60-70 °.
  • FIG. 15 shows a light distribution graph of the planar light emitting module of Example 3.
  • the average slope of the grooves is 17.5 degrees.
  • the apex angle V is 145 degrees.
  • the spacing between the groove baselines is 55 ⁇ m.
  • the light intensity slightly decreased in the vicinity of 65 ° tilted to the + Y direction side from the + Z direction. However, it can be seen that the luminous intensity changes gradually to around 60-70 degrees.
  • FIG. 16 shows a light distribution graph of the planar light emitting module of Example 1.
  • the average inclination of the grooves is 15 degrees.
  • the apex angle V is 150 degrees.
  • the spacing between the groove baselines is 62 ⁇ m.
  • FIG. 17 shows a light distribution graph of the planar light emitting module of Example 4.
  • the average slope of the grooves is 12.5 degrees.
  • the apex angle V is 155 degrees.
  • the spacing between the groove base lines is 73 ⁇ m. Similar to Example 1, the light intensity in the vicinity of 60-70 degrees inclined to the + Y direction side from the + Z direction was strong, and no decrease in light intensity was observed in this vicinity. The intensity in the ⁇ Y direction was slightly higher than in Example 1.
  • FIG. 18 shows a light distribution graph of the planar light emitting module of Comparative Example 5.
  • the average inclination of the grooves is 10 degrees.
  • the apex angle V is 160 degrees.
  • the spacing between the groove baselines is 90 ⁇ m.
  • the light intensity on the -Y direction side was higher than in the other examples. In addition, a decrease in luminous intensity was observed up to around 30 degrees.
  • the average inclination is preferably 12.5 degrees to 20 degrees. It was also found that the apex angle V is preferably 140 to 155 degrees. When the average inclination or the apex angle V is in such a range, a certain amount of light is emitted in a direction at a low angle with respect to the normal direction of the emission surface, and evenly at various angles until reaching a high angle direction. It was found that light was emitted.
  • FIG. 19 shows the relationship between the apex angle V of the groove and the emitted light beam. It was found that the larger the average slope or the smaller the apex angle V, the larger the amount of light emitted. It was also found that the amount of emitted light beam can be kept at a sufficient level when the average inclination is 12.5 degrees or more or the apex angle V is 155 degrees or less. Even in Example 4 where the emitted light flux was the lowest, 90% or more of the emitted light flux of Comparative Example 3 was obtained.
  • the relationship between the optical element applied to the light guide device and the change in illuminance distribution was examined.
  • the light guide device 60 of Example 1 was installed so as to face the irradiated surface 80.
  • the deflection surface 41 faces the irradiated surface 80. Drawing of the smooth surface around the deflection surface 41 is omitted (see FIG. 6).
  • the light traveling along the emission direction Ex1 travels toward the irradiated surface 80 while diffusing. Such light illuminates the illuminated surface 80.
  • a point light source group not shown in FIG. 20 was turned on and light was transmitted through the light guide device 60 from the incident direction In.
  • the illuminance on the irradiated surface 80 was measured.
  • the distance between the deflection surface 41 and the irradiated surface 80 was 60 cm.
  • FIGS. 21 and 22 were obtained from the measured values of illuminance in the + Y direction and the ⁇ X direction from the reference point Re.
  • the dimensions of the light guide plate and the polarizing plate are as shown in dimensions af of FIG.
  • the vertical axis of the graph represents the illuminance ratio. That is, the illuminance at each distance where the maximum illuminance is obtained for each planar light emitting module is 1, and the illuminance value at each distance is expressed as a ratio. The same shall apply hereinafter.
  • 21 and 22 will be used to explain the effect of the ridges and grooves meandering.
  • 21 and 22 are graphs showing the illuminance distribution of Example 1 (Wo1) and Comparative Examples 6 (Co6) and 7 (Co7).
  • Wo Example 1
  • Co6 Comparative Examples 6
  • Co7 Comparative Examples 6
  • Co7 Comparative Examples 7
  • FIG. 21 shows the + Y direction
  • FIG. 22 shows the ⁇ X direction.
  • Comparative Examples 6 and 7 and Example 1 are different in the following points.
  • the light guide plate of Comparative Example 6 is provided with straight grooves (Straight) instead of meandering grooves (Meander).
  • no protrusions are provided on the internal reflection surface. Therefore, the internal reflection surface is a specular surface.
  • the apex angle V is 150 degrees (V150).
  • an illuminance maximum point Ma1 was found in the vicinity of a distance of 400 to 500 mm from the reference point.
  • a local maximum point Ma2 of illuminance was observed near a distance of 1,000 mm from the reference point. These maximum points were visible as bright lines on the irradiated surface.
  • the illuminated surface in a low angle direction with respect to the normal direction of the deflecting surface 41 that is, the illuminated surface in the vicinity is brightly illuminated, and the high angle direction It was possible to smoothly change the illuminance distribution up to the irradiated surface in FIG. These effects are thought to depend on the presence of ridges and meandering grooves.
  • 23 and 24 show graphs representing the illuminance distributions of Examples 4, 1, and 2 and Comparative Examples 3, 8, and 2.
  • FIG. 23 shows the + Y direction.
  • FIG. 24 shows the ⁇ X direction.
  • Comparative Example 8 a reflective sheet is provided on the deflection surface side as in Comparative Example 2 (Reversed, FIG. 10).
  • Comparative Example 2 a groove having an apex angle V of 150 degrees is provided on the deflection surface.
  • Comparative Example 8 a groove having an apex angle V of 130 is provided on the deflection surface. Further, each of the grooves is straight (Straight) unlike the first embodiment.
  • 25 and 26 are graphs showing the illuminance distributions of Example 5-7 and Comparative Example 9.
  • FIG. 25 is the + Y direction.
  • FIG. 26 is the ⁇ X direction.
  • Example 1 in each Example and Comparative Example.
  • the contour line of the groove in the cross section is a trapezoid.
  • the width of the upper base Bu shown in FIG. 3 is 2.5 ⁇ m.
  • the average slope and apex angle V of the side portions are Example 5 (12.5 degrees, V155), Example 6 (15 degrees, V150), Example 7 (17.5 degrees, V145), and Comparative Example, respectively. 9 (25 degrees, V130).
  • FIG. 27 and 28 show graphs showing the illuminance distributions of Examples 8, 9, and 1 and Comparative Example 10.
  • FIG. 27 shows the + Y direction.
  • FIG. 28 is the ⁇ X direction.
  • Example 1 the side portion of the groove in the cross section is curved.
  • the side part of the groove in the cross section is linear.
  • the apex angle V is constant at 150 degrees.
  • the side slope is constant at 15 degrees.
  • the apex angle V in the cross section is 150 degrees at the deepest part of the groove.
  • the apex angle V is 140 degrees at the shallowest part of the groove, that is, at the edge of the groove.
  • the slope of the tangent on the side of the groove changes smoothly from 20 degrees to 15 degrees as the depth in the groove increases.
  • the apex angle V in the cross section is 155 degrees at the deepest part of the groove.
  • the apex angle V is 140 degrees at the shallowest part of the groove, that is, at the edge of the groove.
  • the slope of the tangent to the side of the groove changes smoothly from 20 degrees to 12.5 degrees as the depth in the groove increases.
  • the groove of Comparative Example 10 is a groove having a trapezoidal basic shape. Furthermore, in Comparative Example 10, the apex angle V in the cross section is 120 degrees at the deepest portion of the groove. The apex angle V is 60 degrees at the shallowest part of the groove, that is, at the edge of the groove. The slope of the tangent on the side of the groove changes smoothly from 60 degrees to 30 degrees as the depth in the groove increases.
  • FIGS. 29 and 30 are graphs showing the illuminance distributions of Examples 1 and 10-13 and Comparative Examples 7 and 11.
  • FIG. 29 shows the + Y direction.
  • FIG. 30 shows the ⁇ X direction.
  • the ridge of Example 1 is a lenticular with an aspect ratio of 20%.
  • the angle formed by the normal of the contour line of the ridge in the section of the ridge with respect to the reference plane is 53.1 degrees at the base of the ridge, depending on the height in the ridge, and the vertex of the ridge. Vary to 0 degrees.
  • Each embodiment differs from the first embodiment in the following points.
  • Example 10 the shape of the outline of the cross-section of the ridges was radiation (Parabora).
  • the parabola is expressed by the following mathematical formula.
  • V V top ⁇ kU 2 (formula ⁇ parabola)
  • the contour line when the ridge 51 constituting the internal reflection surface 42 is cut along the XZ plane is defined as the cross-sectional shape of the ridge 51.
  • a ridge 51 is shown as one representative ridge.
  • an intersection line between the XZ plane and the bottom surface of the protrusion 51 is defined as an intersection line 53.
  • the center of the intersection line 53 is newly set as the origin of the UV coordinate system.
  • the axis parallel to the X axis is taken as the U axis.
  • An axis parallel to the Z axis is taken as a V axis.
  • V V top ⁇ kU 2 (formula ⁇ parabola).
  • the ridge was a lenticular lens having an elliptical cross section. That is, the shape of the outline of the cross section of the ridge was an elliptical arc.
  • the ellipse that is the origin of the elliptical arc will be described with the help of the UV coordinate system shown in FIG.
  • the ellipse is represented by the following formula.
  • Example 13 as in Example 1, the contour line of the cross section of the ridge was lenticular. However, the aspect ratio was set to 35%.
  • the angle formed by the normal of the contour line of the ridge in the section of the ridge with respect to the reference plane is 72.5 degrees at the base of the ridge, depending on the height in the ridge, and the vertex of the ridge. Vary to 0 degrees.
  • the shape of the contour line of the cross section of the ridge was a trapezoid having a wide base on the ridge base side.
  • the angle between the leg and the lower base was 55 degrees.
  • the contour line of the ridge in the section of the ridge is preferably a smoothly curved arc, elliptical arc, or parabola.
  • the cross-sectional shape of the ridges is trapezoidal as in Comparative Example 11, a minimum illuminance point is seen in the vicinity of a distance of 1000 mm from the reference point, which is not a preferable illuminance distribution.
  • the angle formed by the tangent of the contour line of the ridge at the base of the ridge with respect to the reference plane is 60 degrees or more.
  • the illuminance is maximum when the distance from the reference point is 500 mm. For this reason, the illuminance near the reference point decreased, and the degree of decrease was milder than those of Comparative Examples 2 and 8.
  • the angle formed by the tangent line of the contour line of the ridge at the base of the ridge with respect to the reference plane is 60 degrees or less.
  • the vicinity of the reference point has the maximum illuminance, and the illuminance changes smoothly, which is more preferable. It has been found that having the shape of the ridges as described above is suitable for obtaining a stretched light irradiation image.
  • 32 and 33 show graphs representing the illuminance distributions of Examples 1 and 14.
  • FIG. 32 shows the + Y direction.
  • FIG. 33 shows the ⁇ X direction.
  • the reflection sheet of Example 1 is a diffusion type (Diffuser type) as described above.
  • the reflecting surface has a diffuse reflectance of 90% or more. Such a reflective surface covers the internal reflective surface of the light guide plate.
  • the reflective sheet of Example 14 is a mirror surface type.
  • the reflecting surface is a mirror surface.
  • Such a reflective surface covers the internal reflective surface of the light guide plate.
  • the diffuse reflectance of the reflective surface is preferably 90% or more. It has been found that limiting the reflection surface of the reflection sheet as described above is particularly suitable for increasing the illuminance immediately below the planar light emitting module. Further, the fact that the diffuse reflectance of the reflection sheet influences the illuminance distribution in this way coincides with a large amount of light emitted from the internal reflection surface 42 as shown in FIG.
  • the illuminance distribution in the X-axis direction was also affected.
  • FIG. 34 shows a graph representing the illuminance distribution of Examples 1 and 15 and Comparative Examples 12-13.
  • FIG. 35 is a graph showing the illuminance distribution of Examples 2 and 16-17 and Comparative Example 14-15. 34 and 35 both show the illuminance distribution in the + Y direction.
  • the meandering of the grooves on the deflection surfaces of Examples 1 and 2 is as described above. That is, the unit length Ul of the meandering of the base line of the groove is 0.5 mm. The amplitude of the meandering of the groove baseline is 70 ⁇ m (0.07 mm). The ⁇ value is 0.14. On the other hand, the unit length Ul of the other examples and comparative examples is set to 0.5 mm, which is the same as those of Examples 1 and 2.
  • the meandering amplitude of Comparative Examples 12 and 14 is 30 ⁇ m (0.03 mm). The ⁇ value is 0.06.
  • the meandering amplitude of Comparative Examples 13 and 15 is 50 ⁇ m (0.05 mm). The ⁇ value is 0.10.
  • the amplitude of meandering in Example 16 is 60 ⁇ m (0.06 mm).
  • the ⁇ value is 0.12.
  • the amplitude of meandering in Examples 15 and 17 is 100 ⁇ m (0.10 mm).
  • the ⁇ value is 0.20.
  • FIG. 36 schematically illustrates a cross-sectional feature of the light guide device 90 according to the eighteenth embodiment.
  • the light guide device 90 includes a light guide plate 85.
  • the light guide plate 85 includes a deflection surface 81.
  • the deflection surface 81 is provided with grooves 87a-e.
  • the slope Ob1 on the side closer to the light receiving surface is smaller than the slope Ob2 on the side farther from the light receiving surface.
  • Ob1 is 15 degrees and Ob2 is 40 degrees.
  • Other features of the groove are the same as those in the first embodiment. The same applies to the grooves 87a and ce.
  • FIG. 37 shows a light distribution graph of the planar light emitting module manufactured using the light guide device of Example 18.
  • a light distribution curve 83 is a light distribution curve of the first embodiment.
  • the light distribution curve 84 is the light distribution curve of Example 18.
  • -90 degrees represents the -Y direction shown in FIGS. 1 and 18, and 90 degrees represents the + Y direction shown in FIGS.
  • the light ray 57c is irregularly reflected by the reflection surface 49, and a part thereof is emitted from the slope of the side portion La1 of the groove 87c.
  • Such a mode of emission occurs both in the light guide device 40 according to FIG. 5 and in the light guide device according to the first embodiment. Therefore, as shown in FIG. 37, there is no dramatic change in the light distribution characteristics between the light distribution curve 83 and the light distribution curve 84.
  • the light ray 57d is irregularly reflected by the reflection surface 49, and a part of the light ray e is emitted from a flat surface between the grooves 87d and e. Therefore, in the light distribution curve 83 shown in FIG. 37, the light intensity increases in a region where the angle is smaller than +60 degrees compared to the light distribution curve 84.
  • the light ray 57d is irregularly reflected by the reflecting surface 49, and a part of the light ray 57f is emitted from the side portion La1 of the groove 87e, but is incident again on the side portion La2 of the groove 87e. Therefore, the light beam 57f further propagates in the light guide plate along the light guide direction Gu.
  • the light beam 57f was supposed to be emitted in a high angle direction with respect to the normal direction of the emission surface, but this is hindered by the side portion La2 having a large inclination Ob2. For this reason, in the light distribution curve 83 shown in FIG. 37, the light intensity decreases in a region where the angle is larger than +60 degrees compared to the light distribution curve 84.
  • the slope of the slope farther from the light receiving surface may be reduced.
  • the slope of the slope farther from the light receiving surface is preferably in the range of 12.5 degrees to 20 degrees in accordance with the slope of the slope closer to the light receiving face.
  • Example 18 when light is emitted in a higher angle direction, it is preferable that the slope of the slope farther from the light receiving surface among the slopes of the groove is also in the range of 12.5 degrees to 20 degrees. Indicated. By using such a groove, a planar light emitting module of still another embodiment can be obtained.
  • FIG. 38 is a front view of the planar light emitting module 95 of Example 19.
  • FIG. The planar light emitting module 95 is different from the planar light emitting module 70 shown in FIG. 6 in that the reflecting material 67 is removed and a point light source group 96 facing the end surface 43b is provided.
  • the 38 is provided with two point light source groups.
  • the first point light source group is a point light source group 66.
  • the second point light source group is a point light source group 96.
  • the light guide plate 45 has two incident end faces.
  • the light receiving surface of the end surface 43a is defined as a first light receiving surface.
  • the light receiving surface of the end face 43 a faces the point light source group 66.
  • the light receiving surface of the end face 43b is defined as a second light receiving surface.
  • the light receiving surface of the end face 43 b faces the point light source group 96.
  • the first and second light receiving surfaces face each other with the central portion of the light guide plate 65 interposed therebetween.
  • a deflection surface 41 is provided at the center of the light guide plate 65.
  • the grooves 47a and b provided in the deflection surface 41 shown in FIG. 38 have an average slope in the range of 12.5 degrees to 20 degrees on both the end face 43a side and the end face 43b side. Therefore, the deflection surface 41 functions as a light emitting surface having two emission directions Ex1 and Ex3.
  • the light from the point light source group 66 shown in FIG. 38 is emitted toward the light receiving surface side of the end face 43b along the emission direction Ex1.
  • the light from the point light source group 96 is emitted toward the light receiving surface side of the end face 43a along the emission direction Ex3.
  • 40 light guide device 41 deflection surface, 42 internal reflection surface, 43a end surface, 43b end surface, 44 cross section, 45 light guide plate, 46a-d center, 47a-d groove, 48a valley, 48b mountain, 49b reflection surface, 50 reflection sheet , 51 ridges, 52 arcs, 55 diffusers, 57a-f rays, 58a-c rays, 60 light guides, 61 bottom surfaces, 63 smooth surfaces, 65 light guide plates, 66 point light source groups, 67 reflectors, 68 reflections Sheet, 70 planar light emitting module, 71 deflection surface, 75 light guide device, 77a-d linear groove, 80 illuminated surface, 81 deflection surface, 83 light distribution curve, 84 light distribution curve, 85 light guide plate, 87a- e Groove, 90 light guide device, 95 optical module, 96 point light source group An angle, Bc1-2 emission direction, B1 bottom bottom, Bu top bottom, Co comparison example, Dp depth, Dx light distribution curve, Dy light distribution curve,

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  • Engineering & Computer Science (AREA)
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Abstract

A light guide device (40) comprising a light guide plate (45) and a reflection sheet (50). The light guide plate (45) has: an incident end surface (43a) having a light-receiving surface; a lower base surface having a deflection surface (41); and an upper base surface having an internal reflection surface (42). The reflection sheet (50) faces the internal reflection surface (42). The deflection surface (41) has a plurality of grooves (47a–d). The grooves (47a–d) smoothly meander, when the light guide plate (45) is viewed in the planar view. The upper base surface also has protruding ridges (51) provided in the internal reflection surface (42). In a cross-section parallel to the normal direction of the light-receiving surface and the normal direction of a reference plane (Ps) in which the light guide plate (45) expands, the average gradient of a side section of the contour lines of the grooves (47a–d) relative to the reference plane (Ps) is 12.5–20° on the light-receiving surface side.

Description

導光装置Light guide device
　本発明は導光装置に関する。 The present invention relates to a light guide device.
　特許文献１にはエッジライト方式の照明装置に用いられる導光装置が記載されている。かかる導光装置は導光板と反射シートを備える。導光板の主たる面のうち一方の面は出射面となっている。出射面には導光方向に対して平行なレンチキュラーレンズが設けられている。また導光板の主たる面のうち他方の面には導光方向に対して直交するＶ字溝が設けられている。導光板の側面は入射端面となっている。入射端面から導光板に対して入射した光はＶ字溝及び反射シートで反射する。光はさらにレンチキュラーレンズを通って出射面から出射する。 Patent Document 1 describes a light guide device used in an edge light type illumination device. Such a light guide device includes a light guide plate and a reflection sheet. One of the main surfaces of the light guide plate is an emission surface. A lenticular lens parallel to the light guide direction is provided on the exit surface. A V-shaped groove orthogonal to the light guide direction is provided on the other surface of the main surfaces of the light guide plate. The side surface of the light guide plate is an incident end surface. Light incident on the light guide plate from the incident end face is reflected by the V-shaped groove and the reflection sheet. The light further exits from the exit surface through the lenticular lens.
国際公開第２０１４／１８１８６５号International Publication No. 2014/181865
　本発明の目的は導光板を備える導光装置であって、導光板の側方から入射する光を導光装置内で拡散させるとともに、導光板の主たる面を出射面として光を出射する導光装置を提供することである。 An object of the present invention is a light guide device including a light guide plate, which diffuses light incident from the side of the light guide plate in the light guide device and emits light using the main surface of the light guide plate as an output surface. Is to provide a device.
　本発明ではさらに導光板の入射端面に対して光が入射しているとともに、導光板の出射面が、出射面から光の照射を受ける被照射面と正対している場合に、出射面の法線方向に対して低角度、概ね２０～３０度の方向において明るく、かつ高角度、概ね６０～７０度の方向まで滑らかに変化する照度分布を得ることを課題とする。 In the present invention, when the light is incident on the incident end face of the light guide plate and the exit surface of the light guide plate faces the irradiated surface that is irradiated with light from the exit surface, the exit surface method is used. It is an object to obtain an illuminance distribution that is bright in a direction at a low angle, approximately 20 to 30 degrees with respect to the line direction, and smoothly changes to a direction at a high angle, approximately 60 to 70 degrees.
[１]　導光板と反射シートとを備える導光装置であって、
　前記導光板は、受光面を有する入射端面と、偏向面を有する下底面と、内部反射面を有する上底面とを有し、
　前記反射シートは前記内部反射面に対向し、
　前記偏向面は互いに並行するとともに深さに応じて狭くなる複数の溝を有し、
　前記溝は前記受光面の近傍から前記受光面の遠方に向かう方向（以下、導光方向という。）に順に配置されるとともに、前記導光板を平面視した時、滑らかに蛇行しており、
　前記上底面はさらに、前記内部反射面に設けられた凸条であって、互いに並行するとともに、前記導光方向に沿う向きに延びる凸条を有し、
　前記受光面の法線と、前記導光板が拡がる基準平面の法線とに平行である断面において、前記基準平面に対する前記溝の輪郭線の側部の平均斜度は前記受光面の側において１２．５度～２０度であり、
　前記偏向面は前記受光面から遠い側に対して光を出射する発光面として機能する、
　導光装置。
[２]　光源から前記導光板の有する入射端面に対して光が入射する場合に、
　前記入射した光の一部は前記溝にて反射することで拡散し、さらに前記内部反射面にて反射するとともに前記凸条にて拡散し、さらに前記偏向面から出射し、
　また、前記入射した光の他の一部は、前記内部反射面で反射することなく出射し、さらに前記反射シートで反射することで前記内部反射面より前記導光板内に再進入し、さらに前記偏向面から出射する、
　ことにより前記偏向面は前記発光面として機能する、
　［１］の導光装置。
［３］　前記溝の輪郭線の側部の平均斜度は１３．５度～１７．５度である、
　［１］又は［２］の導光装置。
［４］　前記溝の輪郭線は左右対称な台形又は三角形であり、
　前記溝の輪郭線が台形であれば前記輪郭線の最深部の幅は１～２５０μｍであり、
　前記溝の深さは２～１００μｍである、
　［１］～［３］の導光装置。
［５］　前記溝の輪郭線の接線が前記基準平面に対して成す傾斜角は、前記溝の中での深さが大きくなるにつれて単調に小さくなるとともに、前記溝の中での深さに応じて滑らかに変化する、
　［４］の導光装置。
［６］　前記複数の溝の間で前記溝の蛇行の位相は互いに一致しており、
　前記溝の蛇行の谷に対して、前記溝の蛇行の振幅の中心を超えて、隣接する他の前記溝の蛇行の山が入り込む、
　［１］～［５］のいずれかの導光装置。
［７］　前記凸条の断面における前記凸条の輪郭線は滑らかに湾曲する円弧、楕円弧、又は放物線からなり、
　前記凸条の輪郭線が、前記凸条の基部において、前記基準平面に対して成す角が６０度以下である、
　［１］～［６］のいずれかの導光装置。
［８］　前記偏向面は前記下底面の中央に位置し、
　前記下底面は前記偏向面を取り囲む滑面を有する、
　［１］～［７］のいずれかの導光装置。
［９］　［１］～［８］のいずれかの導光装置と、点光源群とを備える面状発光モジュールであって
　前記受光面は点光源群と対向し、
　前記点光源群は前記偏向面と平行な方向に所定の間隔で列をなす複数の点光源を有する、
　面状発光モジュール。
［１０］　前記点光源群を２個備え、ここで各点光源群を第１及び第２の点光源群と称し、
　前記導光板は前記入射端面を２面有し、ここで各入射端面は、前記受光面として、前記偏向面を挟んで互いに対向する第１及び第２の受光面をそれぞれ有し、
　前記第１及び第２の受光面はそれぞれ前記第１及び第２の点光源群と対向する、
　ことにより前記偏向面は、前記第１の点光源群の光を前記第２の受光面の側に対して出射するとともに、前記第２の点光源群の光を前記第１の受光面の側に対して出射する発光面として機能する、
　［９］の面状発光モジュール。
［１１］　前記導光板の前記下底面と対向するとともに、前記偏向面から出射する光を散乱する拡散板、又は
　前記導光板の前記下底面と対向するとともに、前記偏向面から出射する光を透過する透明な保護板をさらに有する、
　［９］又は［１０］の面状発光モジュール。 [1] A light guide device comprising a light guide plate and a reflective sheet,
The light guide plate has an incident end surface having a light receiving surface, a lower bottom surface having a deflection surface, and an upper bottom surface having an internal reflection surface,
The reflective sheet faces the internal reflective surface,
The deflection surface has a plurality of grooves parallel to each other and narrowing according to the depth,
The grooves are sequentially arranged in the direction from the vicinity of the light receiving surface toward the far side of the light receiving surface (hereinafter referred to as the light guide direction), and meandering smoothly when the light guide plate is viewed in plan view,
The upper bottom surface is a ridge provided on the internal reflection surface, and has a ridge that is parallel to each other and extends in a direction along the light guide direction,
In a cross section parallel to the normal line of the light receiving surface and the normal line of the reference plane in which the light guide plate extends, the average slope of the side of the contour line of the groove with respect to the reference plane is 12 on the light receiving surface side. .5 degrees to 20 degrees,
The deflection surface functions as a light emitting surface that emits light to a side far from the light receiving surface.
Light guide device.
[2] When light is incident on the incident end face of the light guide plate from a light source,
A part of the incident light is diffused by being reflected by the groove, is further reflected by the internal reflection surface and is diffused by the ridge, and is further emitted from the deflection surface,
Further, the other part of the incident light exits without being reflected by the internal reflection surface, and further re-enters the light guide plate from the internal reflection surface by being reflected by the reflection sheet. Emanating from the deflection surface,
Thus, the deflection surface functions as the light emitting surface.
[1] The light guide device.
[3] The average slope of the side portion of the groove contour line is 13.5 degrees to 17.5 degrees.
The light guide device according to [1] or [2].
[4] The outline of the groove is a symmetrical trapezoid or triangle,
If the contour line of the groove is trapezoidal, the width of the deepest part of the contour line is 1 to 250 μm,
The depth of the groove is 2 to 100 μm.
[1] to [3].
[5] The inclination angle formed by the tangent line of the contour line of the groove with respect to the reference plane monotonously decreases as the depth in the groove increases, and depends on the depth in the groove. Change smoothly
[4] The light guide device.
[6] The meandering phases of the grooves coincide with each other among the plurality of grooves,
With respect to the meandering valley of the groove, beyond the center of the amplitude of the meandering of the groove, the meandering mountain of another adjacent groove enters.
The light guide device according to any one of [1] to [5].
[7] The outline of the ridge in the cross section of the ridge consists of a smoothly curved arc, elliptical arc, or parabola,
In the base of the ridge, the angle formed by the contour line of the ridge with respect to the reference plane is 60 degrees or less.
The light guide device according to any one of [1] to [6].
[8] The deflection surface is located in the center of the lower bottom surface,
The lower bottom surface has a smooth surface surrounding the deflection surface;
The light guide device according to any one of [1] to [7].
[9] A planar light emitting module comprising the light guide device according to any one of [1] to [8] and a point light source group, wherein the light receiving surface faces the point light source group,
The point light source group includes a plurality of point light sources arranged in rows at predetermined intervals in a direction parallel to the deflection surface.
Planar light emitting module.
[10] Two point light source groups are provided, where the point light source groups are referred to as first and second point light source groups,
The light guide plate has two incident end surfaces, and each incident end surface has first and second light receiving surfaces facing each other across the deflection surface as the light receiving surfaces, respectively.
The first and second light-receiving surfaces are opposed to the first and second point light source groups, respectively.
Accordingly, the deflecting surface emits the light of the first point light source group toward the second light receiving surface side, and emits the light of the second point light source group to the first light receiving surface side. Function as a light emitting surface that emits
[9] The planar light emitting module according to [9].
[11] A diffusion plate that opposes the lower bottom surface of the light guide plate and scatters light emitted from the deflection surface, or transmits light emitted from the deflection surface while facing the lower bottom surface of the light guide plate. Further having a transparent protective plate,
The planar light emitting module according to [9] or [10].
　本発明では導光装置の備える導光板の出射面が被照射面と正対している場合に、出射面の法線方向に対して低角度の方向において明るく、かつ高角度の方向まで滑らかに変化する照度分布を得ることができる。 In the present invention, when the exit surface of the light guide plate provided in the light guide device faces the irradiated surface, it changes brightly in a low angle direction with respect to the normal direction of the exit surface and smoothly changes to a high angle direction. Illuminance distribution can be obtained.
導光装置の斜視図である。It is a perspective view of a light guide device. －Ｚ方向から見た受光面の平面図である。FIG. 6 is a plan view of a light receiving surface viewed from the −Z direction. 断面における溝の輪郭線を表す端面図である。It is an end elevation showing the outline of a groove in a section. 凸条の断面図である。It is sectional drawing of a protruding item | line. 導光装置の断面における光路の模式図である。It is a schematic diagram of the optical path in the cross section of a light guide device. 実施例１の面状発光モジュールの平面図であるIt is a top view of the planar light emitting module of Example 1. 実施例１の面状発光モジュールのゴニオマップである。3 is a gonio map of the planar light emitting module of Example 1. 実施例１の面上発光モジュールの配光分布グラフである。3 is a light distribution graph of the on-surface light emitting module of Example 1; 比較例１の導光板の斜視図である。6 is a perspective view of a light guide plate of Comparative Example 1. FIG. 比較例２の導光装置の斜視図である。It is a perspective view of the light guide device of comparative example 2. 比較例２の導光装置の配光分布グラフである。10 is a light distribution graph of the light guide device of Comparative Example 2. 溝の平均斜度が２５度である比較例３の配光分布グラフである。It is a light distribution graph of the comparative example 3 whose average inclination of a groove | channel is 25 degree | times. 溝の平均斜度が２２．５度である比較例４の配光分布グラフである。It is a light distribution graph of the comparative example 4 whose average inclination of a groove | channel is 22.5 degree | times. 溝の平均斜度が２０度である実施例２の配光分布グラフである。It is a light distribution graph of Example 2 whose average inclination of a groove | channel is 20 degree | times. 溝の平均斜度が１７．５度である実施例３の配光分布グラフである。It is a light distribution graph of Example 3 whose average inclination of a groove | channel is 17.5 degree | times. 溝の平均斜度が１５度である実施例１の配光分布グラフである。It is a light distribution graph of Example 1 whose average inclination of a groove | channel is 15 degree | times. 溝の平均斜度が１２．５度である実施例４の配光分布グラフである。It is a light distribution graph of Example 4 whose average inclination of a groove | channel is 12.5 degree | times. 溝の平均斜度が１０度である比較例５の配光分布グラフである。It is a light distribution graph of the comparative example 5 whose average inclination of a groove | channel is 10 degree | times. 溝の頂角と出射光束との関係を表すグラフである。It is a graph showing the relationship between the apex angle of a groove | channel and an emitted light beam. 実施例１の導光装置の斜視図である。It is a perspective view of the light guide device of Example 1. ＋Ｙ方向における照度分布を表すグラフである。It is a graph showing the illumination distribution in + Y direction. ＋Ｘ方向における照度分布を表すグラフである。It is a graph showing the illumination distribution in + X direction. ＋Ｙ方向における照度分布を表すグラフである。It is a graph showing the illumination distribution in + Y direction. ＋Ｘ方向における照度分布を表すグラフである。It is a graph showing the illumination distribution in + X direction. ＋Ｙ方向における照度分布を表すグラフである。It is a graph showing the illumination distribution in + Y direction. ＋Ｘ方向における照度分布を表すグラフである。It is a graph showing the illumination distribution in + X direction. ＋Ｙ方向における照度分布を表すグラフである。It is a graph showing the illumination distribution in + Y direction. ＋Ｘ方向における照度分布を表すグラフである。It is a graph showing the illumination distribution in + X direction. ＋Ｙ方向における照度分布を表すグラフである。It is a graph showing the illumination distribution in + Y direction. ＋Ｘ方向における照度分布を表すグラフである。It is a graph showing the illumination distribution in + X direction. 凸条の断面図である。It is sectional drawing of a protruding item | line. ＋Ｙ方向における照度分布を表すグラフである。It is a graph showing the illumination distribution in + Y direction. ＋Ｘ方向における照度分布を表すグラフである。It is a graph showing the illumination distribution in + X direction. ＋Ｙ方向における照度分布を表すグラフである。It is a graph showing the illumination distribution in + Y direction. ＋Ｙ方向における照度分布を表すグラフである。It is a graph showing the illumination distribution in + Y direction. 実施例１８の導光装置の断面の模式図である。FIG. 20 is a schematic diagram of a cross section of a light guide device in Example 18. 実施例１８の配光分布グラフである。22 is a light distribution graph of Example 18. 実施例１９の面状発光モジュールの正面図である。It is a front view of the planar light emitting module of Example 19.
　本実施形態において光の拡散（spreading）とは、その三次元の寸法を巨視的スケールで設計された光学的要素（optical element）によって光が拡散することをいう。ただし、光学的要素内において光が通り得る全ての光学的経路が完全に予測されていることを意図するものではない。光の拡散は配光特性の測定などの実験によって確認されるものである。特に言及の無い限り、本実施形態における光の拡散（spreading）は、微粒子や粗面による光の乱反射や光の散乱の結果である偶発的な光の拡散（diffusion）と区別される。本実施形態にかかる光の拡散（spreading）のための光学的要素と、本実施形態で用いられる光の散乱又は乱反射のための光学的要素が組み合わさって光に影響を及ぼした場合の結果は、光の拡散（spreading）とする。 In the present embodiment, light spreading means that light is diffused by an optical element whose three-dimensional dimensions are designed on a macroscopic scale. However, it is not intended that all optical paths that light can take within an optical element are fully predicted. Light diffusion is confirmed by experiments such as measurement of light distribution characteristics. Unless otherwise stated, the light spreading in this embodiment is distinguished from the accidental diffusion of light, which is the result of light irregular reflection or light scattering by fine particles or rough surfaces. When the optical element for spreading of light according to the present embodiment and the optical element for scattering or irregular reflection of light used in the present embodiment are combined to affect light, the result is as follows: And light spreading.
　図１に本実施形態に係る導光装置４０を示す。導光装置４０は導光板４５と反射シート５０とを備える。導光板４５は基準平面Ｐｓ上に拡がっている。図中で基準平面ＰｓはＸＹ平面に平行である。導光板４５は偏向面４１を有する下底面及び内部反射面４２を有する上底面を備える。図中で偏向面４１及び内部反射面４２はＸＹ平面に沿って拡がる。 FIG. 1 shows a light guide device 40 according to this embodiment. The light guide device 40 includes a light guide plate 45 and a reflection sheet 50. The light guide plate 45 extends on the reference plane Ps. In the drawing, the reference plane Ps is parallel to the XY plane. The light guide plate 45 includes a lower bottom surface having a deflection surface 41 and an upper bottom surface having an internal reflection surface 42. In the drawing, the deflection surface 41 and the internal reflection surface 42 extend along the XY plane.
　図１に示す導光板４５の下底面は導光板４５の主たる面の一方である。上底面は導光板４５の主たる面の他方である。導光板４５の上底面と下底面との間には側面がある。側面の一部は受光面を備える端面４３ａとなっている。端面４３ａは入射側面として機能する。図中の端面４３ａはＸＺ平面に平行である。 The lower bottom surface of the light guide plate 45 shown in FIG. The upper bottom surface is the other main surface of the light guide plate 45. There is a side surface between the upper bottom surface and the lower bottom surface of the light guide plate 45. A part of the side surface is an end surface 43a having a light receiving surface. The end surface 43a functions as an incident side surface. The end face 43a in the drawing is parallel to the XZ plane.
　図１には導光板４５の断面４４が表されている。断面４４は基準平面Ｐｓの法線と、端面４３ａの成す受光面の法線とに平行である。図中では断面４４はＹＺ平面に平行である。 FIG. 1 shows a cross section 44 of the light guide plate 45. The cross section 44 is parallel to the normal line of the reference plane Ps and the normal line of the light receiving surface formed by the end face 43a. In the drawing, the cross section 44 is parallel to the YZ plane.
　図１において図示されていない光源から端面４３ａに対して入射方向Ｉｎに平行に光が入射する。入射方向Ｉｎは端面４３ａの成す受光面に対して直角であることが好ましい。図中で入射方向ＩｎはＹ軸に平行である。 1 Light enters from the light source not shown in FIG. 1 parallel to the incident direction In with respect to the end face 43a. The incident direction In is preferably perpendicular to the light receiving surface formed by the end face 43a. In the figure, the incident direction In is parallel to the Y axis.
　図１に示す端面４３ａの成す受光面から導光板４５に進入した光は導光方向Ｇｕに沿って導かれる。導光方向Ｇｕは基準平面Ｐｓに平行である。図中では導光方向Ｇｕは端面４３ａの成す受光面の法線に平行である。導光方向Ｇｕは断面４４と平行である。図中では導光方向ＧｕはＹ軸と平行である。 The light that has entered the light guide plate 45 from the light receiving surface formed by the end face 43a shown in FIG. 1 is guided along the light guide direction Gu. The light guide direction Gu is parallel to the reference plane Ps. In the drawing, the light guide direction Gu is parallel to the normal line of the light receiving surface formed by the end face 43a. The light guide direction Gu is parallel to the cross section 44. In the drawing, the light guide direction Gu is parallel to the Y axis.
　図１に示す偏向面４１は導かれた光を出射方向Ｅｘ１に向けて出射する。出射方向Ｅｘ１は端面４３ａの成す受光面から遠い側に向かう方向である。このようにして偏向面４１は発光面として機能する。偏向面４１を発光面として利用するための光学的なモデルは後述する。 The deflection surface 41 shown in FIG. 1 emits the guided light toward the emission direction Ex1. The emission direction Ex1 is a direction toward the far side from the light receiving surface formed by the end face 43a. In this way, the deflection surface 41 functions as a light emitting surface. An optical model for using the deflection surface 41 as a light emitting surface will be described later.
　図１に示す導光板４５の側面の他の一部はさらに端面４３ｂとなっている。端面４３ｂは導光板４５の中央部を挟んで端面４３ａに対向する。端面４３ｂもまた受光面を有することで入射端面となっていてもよい。かかる態様は実施例にて説明する。 The other part of the side surface of the light guide plate 45 shown in FIG. The end surface 43b faces the end surface 43a across the central portion of the light guide plate 45. The end surface 43b may also be an incident end surface by having a light receiving surface. Such an embodiment will be described in Examples.
　図１に示す反射シート５０は内部反射面４２の一部又は全部を覆う。反射シート５０は反射面４９を有する。反射面４９は内部反射面４２に対向する。反射面４９は内部反射面４２に接していてもよく、接していなくてもよい。 The reflective sheet 50 shown in FIG. 1 covers part or all of the internal reflective surface 42. The reflection sheet 50 has a reflection surface 49. The reflection surface 49 faces the internal reflection surface 42. The reflective surface 49 may be in contact with the internal reflective surface 42 or may not be in contact therewith.
　図１に示す反射面４９は光を乱反射させるものであることが好ましい。反射面４９の拡散反射率は９０％以上であることが好ましい。拡散反射率は、乱反射によって拡散する光に関する変数である。拡散反射率は次の通り定義される。通常、反射率の測定は試料に光を照射した時に、試料で反射した光を測定する。反射した光には鏡面反射光と拡散反射光が含まれている。これらを合わせたものを全光線反射光という。全光線反射率は全光線反射光の反射率である。全光線反射率は、試料に入射する光の量に対する、試料で反射された光の量の比率である。拡散反射率は、試料に入射する光の量に対する、拡散反射光の光の量の比率である。拡散反射光の光の量は全光線反射光の光の量から鏡面反射光の光の量を差し引いて得られる。拡散反射光の光の量を選択的に測定するのは難しいため、便宜的に拡散反射率をこのように算出する。 1 is preferably one that diffuses light. The diffuse reflectance of the reflecting surface 49 is preferably 90% or more. The diffuse reflectance is a variable related to light diffused by irregular reflection. The diffuse reflectance is defined as follows. Usually, the reflectance is measured by measuring the light reflected by the sample when the sample is irradiated with light. The reflected light includes specular reflection light and diffuse reflection light. A combination of these is called total light reflected light. The total light reflectance is the reflectance of the total light reflected light. Total light reflectance is the ratio of the amount of light reflected by the sample to the amount of light incident on the sample. The diffuse reflectance is the ratio of the amount of diffusely reflected light to the amount of light incident on the sample. The amount of diffusely reflected light is obtained by subtracting the amount of specularly reflected light from the amount of total reflected light. Since it is difficult to selectively measure the amount of diffuse reflection light, the diffuse reflectance is calculated in this way for convenience.
　図１に示す偏向面４１は溝４７ａ－ｄを有する。偏向面４１は溝によって光を偏向する機能を発揮する。溝４７ａ－ｄにおいては＋Ｚ軸方向に向かって溝中の深さが増大する。溝４７ａ－ｄは溝４７ａ－ｄ中の深さに応じて狭くなる溝である。 The deflection surface 41 shown in FIG. 1 has grooves 47a-d. The deflecting surface 41 exhibits a function of deflecting light by the groove. In the grooves 47a-d, the depth in the grooves increases in the + Z-axis direction. The grooves 47a-d are grooves that become narrow according to the depth in the grooves 47a-d.
　図２には図１の－Ｚ方向から見た偏向面４１が示されている。溝４７ａ－ｄは溝の中心を表すベースラインで表現されている。溝４７ａ－ｄは互いに並行する。溝４７ａ－ｄは端面４３ａの成す受光面の近傍から受光面の遠方に向かう方向に順に配置される。かかる方向は導光方向Ｇｕと一致する。溝４７ａ－ｄは導光方向Ｇｕに沿って進む光を横切る方向に延びている。本実施形態ではかかる方向を長手方向という場合がある。 FIG. 2 shows the deflection surface 41 as viewed from the -Z direction in FIG. The grooves 47a-d are represented by a baseline representing the center of the groove. The grooves 47a-d are parallel to each other. The grooves 47a-d are sequentially arranged in the direction from the vicinity of the light receiving surface formed by the end face 43a to the far side of the light receiving surface. Such a direction coincides with the light guide direction Gu. The grooves 47a-d extend in a direction crossing the light traveling along the light guide direction Gu. In the present embodiment, such a direction may be referred to as a longitudinal direction.
　図２に示す溝４７ａ－ｄの蛇行のベースラインの形状は正弦曲線でもよく、放物線でもよい。図中において溝の縁を表す線は省略されている。図中には溝４７ａ－ｄ以外の溝も表されている。導光方向Ｇｕに沿ってさらに溝４７ａ－ｄと同形状の溝を増やしてもよく、また減らしてもよい。溝の数は適宜設計可能である。 The shape of the meandering baseline of the grooves 47a-d shown in FIG. 2 may be a sine curve or a parabola. In the drawing, the line representing the edge of the groove is omitted. In the figure, grooves other than the grooves 47a-d are also shown. Grooves having the same shape as the grooves 47a-d may be further increased or decreased along the light guide direction Gu. The number of grooves can be designed as appropriate.
　図２に示すように偏向面４１を平面視した時、溝４７ａ－ｄは滑らかに蛇行している。溝４７ａ－ｄの間で蛇行の位相は一致していてもよく、互いに不規則にずれていてもよい。図中では蛇行の位相は一致している。隣り合う溝のベースライン間の間隔は０．０２～２ｍｍが好ましく、０．０５～１．０ｍｍがさらに好ましい。 As shown in FIG. 2, when the deflection surface 41 is viewed in plan, the grooves 47a-d meander smoothly. The meandering phases may match between the grooves 47a-d and may be irregularly shifted from each other. In the figure, the phases of meandering are the same. The distance between the base lines of adjacent grooves is preferably 0.02 to 2 mm, and more preferably 0.05 to 1.0 mm.
　図２に示す溝４７ａ－ｄの蛇行の振幅の中心４６ａ－ｄは各々直線である。本実施形態において蛇行の振幅の中心の用語は蛇行の振動の中心を表す場合がある。中心４６ａ－ｄは互いに平行である。中心４６ａ－ｄは端面４３ａと平行である。図中において中心４６ａ－ｄはＸ軸方向に平行である。溝４７ａ－ｄは互いに交差しないことが好ましい。 The meandering amplitude centers 46a-d of the grooves 47a-d shown in FIG. In the present embodiment, the term of the meandering amplitude center may represent the meandering vibration center. The centers 46a-d are parallel to each other. The center 46a-d is parallel to the end face 43a. In the figure, the center 46a-d is parallel to the X-axis direction. The grooves 47a-d preferably do not cross each other.
　図２に示す溝４７ａのベースラインの蛇行の谷４８ａに対して、隣接する他の溝４７ｂの蛇行の山４８ｂが入り込むことが好ましい。蛇行の山４８ｂはさらに溝４７ａの蛇行の振幅の中心である中心４６ａを超えることが好ましい。他の溝において同様である。これにより、溝が互いに交差することを防止しつつ、一定の面積内に多くの溝を設置することが出来る。このため光の偏向を効率的に行うことが出来る。 It is preferable that the meandering mountain 48b of another adjacent groove 47b enters the meandering valley 48a of the base line of the groove 47a shown in FIG. The meandering mountain 48b preferably further exceeds the center 46a which is the center of the meandering amplitude of the groove 47a. The same applies to the other grooves. Thereby, many grooves can be installed in a certain area while preventing the grooves from crossing each other. For this reason, light deflection can be performed efficiently.
　図２に示す溝４７ａ－ｄのベースラインの蛇行の単位長Ｕｌはいわゆる蛇行の波長である。溝４７ａ－ｄでは単位長Ｕｌ分の蛇行が繰り返される。単位長Ｕｌは３ｍｍ以下が好ましく、１ｍｍ以下がさらに好ましい。中心４６ａ－ｄからのベースラインの変位の最大値を振幅とする。振幅は１ｍｍ以下が好ましく、６００μｍ以下がより好ましい。 The unit length Ul of the meandering of the baseline of the grooves 47a-d shown in FIG. 2 is the so-called meandering wavelength. In the grooves 47a-d, meandering for the unit length Ul is repeated. The unit length Ul is preferably 3 mm or less, and more preferably 1 mm or less. The maximum value of the baseline displacement from the center 46a-d is taken as the amplitude. The amplitude is preferably 1 mm or less, and more preferably 600 μm or less.
　（振幅）／（単位長Ｕｌ）で表される比をα値という場合がある。例えば単位長Ｕｌが０．５ｍｍであり、振幅が７０μｍ（０．０７ｍｍ）である場合、α値は０．１４である。α値は、０．１２以上であることが好ましい。これより小さいと被照射面照度の分布を滑らかに変化させることが難しくなる。 The ratio represented by (amplitude) / (unit length Ul) may be referred to as α value. For example, when the unit length Ul is 0.5 mm and the amplitude is 70 μm (0.07 mm), the α value is 0.14. The α value is preferably 0.12 or more. If it is smaller than this, it will be difficult to smoothly change the illumination surface illumination distribution.
　図３には図１に示す断面４４における溝４７ａの有する輪郭線が表されている。輪郭線において上底Ｂｕは溝４７ａの最も深い部分を表す。上底Ｂｕの幅は適宜設計できる。上底Ｂｕの幅は０でもよい。すなわち溝４７ａは溝４７ａの中で最も深い部分が角張っているＶ字溝であってもよい。 FIG. 3 shows the outline of the groove 47a in the cross section 44 shown in FIG. In the contour line, the upper base Bu represents the deepest portion of the groove 47a. The width of the upper base Bu can be designed as appropriate. The width of the upper base Bu may be zero. That is, the groove 47a may be a V-shaped groove in which the deepest portion of the groove 47a is angular.
　図３に示す溝４７ａの輪郭線において下底Ｂｌは溝４７ａの開口部分を表す。下底Ｂｌの幅は適宜設計できる。溝４７ａの輪郭線において深さＤｐは上底Ｂｕと下底Ｂｌとの間の距離を表す。すなわち深さＤｐは溝４７ａ全体の深さを表す。深さＤｐは２～１００μｍが好ましく、４～１５μｍがさらに好ましい。 In the outline of the groove 47a shown in FIG. 3, the lower base Bl represents the opening of the groove 47a. The width of the lower base Bl can be designed as appropriate. In the outline of the groove 47a, the depth Dp represents the distance between the upper base Bu and the lower base Bl. That is, the depth Dp represents the entire depth of the groove 47a. The depth Dp is preferably 2 to 100 μm, more preferably 4 to 15 μm.
　図３に示す溝４７ａの輪郭線において側部Ｌａ１及び２は溝４７ａの斜面を表す。上底Ｂｕの幅が０より大きい場合は、輪郭線は上底Ｂｕ、下底Ｂｌ及び脚を成す側部Ｌａ１及び２からなる台形であってもよい。台形は左右対称な台形すなわち等脚台形（isosceles trapezoid）であってもよい。上底Ｂｕの幅は好ましくは１～２５０μｍ、さらに好ましくは１～５μｍである。 In the outline of the groove 47a shown in FIG. 3, the side parts La1 and La2 represent the slope of the groove 47a. When the width of the upper base Bu is larger than 0, the outline may be a trapezoid made up of the upper base Bu, the lower base Bl, and the side portions La1 and La2 forming the legs. The trapezoid may be a symmetrical trapezoid, that is, an isosceles trapezoid. The width of the upper base Bu is preferably 1 to 250 μm, more preferably 1 to 5 μm.
　図３に示す上底Ｂｕの幅が０である場合は、輪郭線は下底Ｂｌ及び側部Ｌａ１及び２からなる三角形であってもよい。三角形は左右対称な三角形すなわち下底Ｂｌを底辺とする二等辺三角形（isosceles triangle）であってもよい。 When the width of the upper base Bu shown in FIG. 3 is 0, the outline may be a triangle composed of the lower base Bl and the side portions La1 and La2. The triangle may be a symmetrical triangle, that is, an isosceles triangle with the lower base B1 as the base.
　なお本実施形態において輪郭線が台形又は三角形を成しているという限定は、輪郭線が上底Ｂｕや側部Ｌａ１及び２が厳密に直線で構成されているものに限定されることを意味しない。すなわち後述する例も含めて側部Ｌａ１及び２は曲線で構成されていてもよい。上底Ｂｕもまた曲線で構成されていてもよい。台形は、台形の側部の成す脚が曲線に置き換えられた図形に置き換えてもよい。三角形は、三角形の側部の成す辺が曲線に置き換えられた図形に置き換えてもよい。 In the present embodiment, the limitation that the contour line forms a trapezoid or a triangle does not mean that the contour line is limited to a shape in which the upper base Bu and the side portions La1 and La2 are strictly formed by straight lines. . That is, the side portions La1 and La2 may be configured with a curve including an example described later. The upper base Bu may also be configured with a curve. The trapezoid may be replaced with a figure in which the legs formed on the sides of the trapezoid are replaced with curves. The triangle may be replaced with a figure in which the side formed by the side of the triangle is replaced with a curve.
　図３に示す断面４４において、基準平面Ｐｓに対する側部Ｌａ１及び２の平均斜度を斜度Ｏｂ１及び２と表す。斜度Ｏｂ１は溝４７ａの有する斜面のうち、導光方向の根元側、すなわち受光面に近い側の斜面上の斜度である。斜度Ｏｂ２は溝４７ａの有する斜面のうち、導光方向の末端側、すなわち受光面から遠い側の斜面上の斜度である。 In the cross section 44 shown in FIG. 3, the average slopes of the side portions La1 and La2 with respect to the reference plane Ps are represented as slopes Ob1 and Ob2. The slope Ob1 is the slope on the slope in the light guide direction, that is, the slope closer to the light receiving surface among the slopes of the groove 47a. The slope Ob2 is a slope on the slope in the light guide direction, that is, the slope far from the light receiving surface among the slopes of the groove 47a.
　図１に戻る。溝４７ａは蛇行していることから断面４４と溝４７ａとの成す角度は必ずしも９０度ではない。したがって輪郭線は溝４７ａの斜面を斜めに横切るように進む場合がある。このため図３に示す斜度Ｏｂ１及び２と、溝４７ａの斜面の斜度いわゆる最大斜度とは必ずしも一致しない。 Return to Figure 1. Since the groove 47a meanders, the angle formed by the cross section 44 and the groove 47a is not necessarily 90 degrees. Therefore, the contour line may proceed so as to cross the slope of the groove 47a obliquely. Therefore, the slopes Ob1 and Ob2 shown in FIG. 3 do not necessarily coincide with the so-called maximum slope of the slope of the groove 47a.
　図３に示す斜度Ｏｂ１は側部Ｌａ１及び下底Ｂｌの交差点と、側部Ｌａ１及び上底Ｂｕの交差点とを結ぶ線分と基準平面Ｐｓの成す角度である。斜度Ｏｂ２は側部Ｌａ２及び下底Ｂｌの交差点と、側部Ｌａ２及び上底Ｂｕの交差点とを結ぶ線分と基準平面Ｐｓの成す角度である。側部Ｌａ１及び２が曲線で構成されている場合も同様である。 3 is an angle formed by a line segment connecting the intersection of the side portion La1 and the lower base Bl and the intersection of the side portion La1 and the upper base Bu and the reference plane Ps. The inclination Ob2 is an angle formed by a reference plane Ps and a line segment connecting the intersection of the side portion La2 and the lower base B1, and the intersection of the side portion La2 and the upper base Bu. The same applies to the case where the side portions La1 and La2 are formed of curves.
　図３に示す斜度Ｏｂ１は好ましくは１２．５度～２０度、さらに好ましくは１３．５度～１７．５度である。斜度Ｏｂ２は好ましくは１２．５度～２０度、さらに好ましくは１３．５度～１７．５度である。斜度Ｏｂ２は斜度Ｏｂ１と等しいことが好ましい。 The slope Ob1 shown in FIG. 3 is preferably 12.5 degrees to 20 degrees, more preferably 13.5 degrees to 17.5 degrees. The inclination Ob2 is preferably 12.5 degrees to 20 degrees, more preferably 13.5 degrees to 17.5 degrees. The slope Ob2 is preferably equal to the slope Ob1.
　図３に示す下底Ｂｌ側から見た時の、側部Ｌａ１及び側部Ｌａ２の開き角を頂角Ｖとする。斜度Ｏｂ１及び斜度Ｏｂ２が等しい時、頂角Ｖは１４０～１５５度が好ましく、１４５度～１５３度がさらに好ましい。 The opening angle of the side part La1 and the side part La2 when viewed from the lower base Bl side shown in FIG. When the slope Ob1 and the slope Ob2 are equal, the vertex angle V is preferably 140 to 155 degrees, and more preferably 145 to 153 degrees.
　図３に示す側部Ｌａ１及びＬａ２をそれぞれ曲線で構成された側部Ｌａ３及び４に置き換えてもよい。側部Ｌａ３及び４は下底Ｂｌに近いほど傾斜が大きくなるように湾曲していている。側部Ｌａ３の接線及び側部Ｌａ４の接線が基準平面に対して成す傾斜角は、溝の中での深さが大きくなるにつれて単調に小さくなるとともに、溝の中での深さに応じて滑らかに変化する。 The side portions La1 and La2 shown in FIG. 3 may be replaced with side portions La3 and 4 each formed of a curve. The side parts La3 and La4 are curved so that the inclination becomes larger as they are closer to the lower base Bl. The inclination angle formed by the tangent line of the side portion La3 and the tangent line of the side portion La4 with respect to the reference plane decreases monotonously as the depth in the groove increases, and is smooth according to the depth in the groove. To change.
　図３に示す側部Ｌａ３の接線及び側部Ｌａ４の接線と基準平面Ｐｓとの成す角度は５度～２５度好ましくは１０度～２０度の範囲で滑らかに変化することが好ましい。また本実施形態では便宜的に、図３に示す下底Ｂｌ側から見た時の、側部Ｌａ３の接線及び側部Ｌａ４の接線の開き角を頂角Ｖとする。このように湾曲した溝において頂角Ｖは溝４７ａ中の深さによって変化する。 It is preferable that the angle formed between the tangent line of the side portion La3 and the tangent line of the side portion La4 and the reference plane Ps shown in FIG. 3 changes smoothly in the range of 5 degrees to 25 degrees, preferably 10 degrees to 20 degrees. Further, in this embodiment, for the sake of convenience, the opening angle of the tangent line of the side portion La3 and the tangent line of the side portion La4 when viewed from the lower bottom Bl side shown in FIG. In such a curved groove, the apex angle V changes depending on the depth in the groove 47a.
　図３に示す側部Ｌａ３及び４に示すような曲線を有する輪郭線は例えばスプライン曲線により設計することが出来る。図中において側部Ｌａ３及び４の斜度も斜度Ｏｂ１及び２に等しい。 A contour line having a curve as shown in the side portions La3 and La4 shown in FIG. 3 can be designed by a spline curve, for example. In the figure, the slopes of the side portions La3 and 4 are also equal to the slopes Ob1 and Ob2.
　図１に戻る。溝４７ａ以外の他の溝も断面４４において溝４７ａと同じ形の輪郭線を有することが好ましい。かかる溝の断面形状は溝の中心に沿って進んだ場合にいずれの場所においても同じ形であることが好ましい。かかる溝の断面形状はいずれのＸ座標においても同じ形であることが好ましい。 Return to Figure 1. It is preferable that other grooves than the groove 47a have the same contour line as the groove 47a in the cross section 44. The cross-sectional shape of such a groove is preferably the same at any location when it travels along the center of the groove. The cross-sectional shape of the groove is preferably the same in any X coordinate.
　図１に示す内部反射面４２には凸条５１を含む複数の凸条が設けられている。これらの凸条は互いに並行する。並行する凸条同士の間には基準平面Ｐｓに平行な平面が設けられていてもよい。かかる平面は滑面でもよい。凸条５１は導光板４５の中央部と一体に成形されたものでもよい。導光板４５の中央部に対して別体として取り付けられたものでもよい。凸条５１の中心軸は直線であることが好ましい。 A plurality of ridges including ridges 51 are provided on the internal reflection surface 42 shown in FIG. These ridges are parallel to each other. A plane parallel to the reference plane Ps may be provided between the parallel ridges. Such a plane may be a smooth surface. The protrusion 51 may be formed integrally with the central portion of the light guide plate 45. What was attached as a separate body with respect to the center part of the light-guide plate 45 may be used. The central axis of the ridge 51 is preferably a straight line.
　図１に示す凸条５１を含むこれら凸条は導光方向Ｇｕに沿う向きに延びる。凸条５１は端面４３ａ及びｂの成す受光面に対して直角であることが好ましい。凸条５１は受光面の法線と平行な直線状とすることができる。図中において凸条５１はＹ軸と平行である。 These ridges including the ridge 51 shown in FIG. 1 extend in a direction along the light guide direction Gu. The ridge 51 is preferably perpendicular to the light receiving surface formed by the end surfaces 43a and 43b. The ridge 51 can be a straight line parallel to the normal line of the light receiving surface. In the figure, the ridges 51 are parallel to the Y axis.
　図１に示す凸条５１の高さは１０～５００μｍ、好ましくは１０～５０μｍとすることができる。凸条５１の高さは一定でなくてもよい。凸条同士の中心間間隔は５０～３００μｍとすることができる。凸条５１の高さも含む導光板４５の厚さは１～４ｍｍが好ましく、２～３ｍｍがさらに好ましい。 1 can have a height of 10 to 500 μm, preferably 10 to 50 μm. The height of the ridges 51 may not be constant. The center-to-center distance between the ridges can be 50 to 300 μm. The thickness of the light guide plate 45 including the height of the ridges 51 is preferably 1 to 4 mm, and more preferably 2 to 3 mm.
　図１に示す凸条５１の中心軸に対して直角な断面における、凸条５１の輪郭は楕円弧、円弧、放物線及び多角形のいずれかを成していてもよい。円弧は半円でもよい。凸条は滑らかに湾曲していることが好ましい。 The outline of the ridge 51 in a cross section perpendicular to the central axis of the ridge 51 shown in FIG. 1 may be an elliptical arc, an arc, a parabola, or a polygon. The arc may be a semicircle. It is preferable that the ridge is smoothly curved.
　図１に示す凸条５１はレンチキュラーレンズである。凸条５１が円弧からなるレンチキュラーレンズの場合、凸条５１のアスペクト比について図４の断面図を用いて説明する。 1 is a lenticular lens. When the ridge 51 is a lenticular lens formed of an arc, the aspect ratio of the ridge 51 will be described with reference to the cross-sectional view of FIG.
　図４に示すように凸条５１の成すレンチキュラーレンズの垂直断面においてレンチキュラーレンズを形成する円弧５２の半径をＲａとする。さらに円弧５２の頂点から弦までの距離、すなわち正矢（versed sine）をＶｓとする。このとき、アスペクト比は式：（Ｖｓ／２Ｒａ）×１００（％）で表される。 As shown in FIG. 4, the radius of the arc 52 forming the lenticular lens in the vertical section of the lenticular lens formed by the ridges 51 is represented by Ra. Further, the distance from the apex of the arc 52 to the string, that is, a positive arrow (versed sine) is set as Vs. At this time, the aspect ratio is represented by the formula: (Vs / 2Ra) × 100 (%).
　図４に示す凸条５１のアスペクト比は０％より大きく、３０％以下とすることができる。アスペクト比は２０％が好ましい。円弧５２上の任意の点において、接線が基準平面Ｐｓに対してなす角度は０～８５度、好ましくは０～７０度とすることができる。以下特に断りの無い限り、凸条の断面における凸条の輪郭線の接線の成す角度とは基準平面に対する角度を表すものとする。 The aspect ratio of the ridges 51 shown in FIG. 4 can be greater than 0% and 30% or less. The aspect ratio is preferably 20%. The angle formed by the tangent line with respect to the reference plane Ps at an arbitrary point on the arc 52 can be 0 to 85 degrees, preferably 0 to 70 degrees. Hereinafter, unless otherwise specified, the angle formed by the tangent to the contour line of the ridge in the section of the ridge represents the angle with respect to the reference plane.
　図４に示す角Ａｎは凸条５１の基部における凸条５１の輪郭線の接線が、基準平面Ｐｓと平行な面に対して成す角である。角Ａｎは６０度以下であることが好ましい。アスペクト比が２０％であれば角Ａｎは５３．１度である The angle An shown in FIG. 4 is an angle formed by a tangent to the contour line of the ridge 51 at the base of the ridge 51 with respect to a plane parallel to the reference plane Ps. The angle An is preferably 60 degrees or less. If the aspect ratio is 20%, the angle An is 53.1 degrees.
　図５には導光装置４０の断面を表す端面図が示されている。図５では、前後方向が図１とは反対になっている。図５を用いて以下に偏向面４１を発光面として利用するための光学的なモデルを説明する。 FIG. 5 is an end view showing a cross section of the light guide device 40. In FIG. 5, the front-rear direction is opposite to that in FIG. An optical model for using the deflection surface 41 as a light emitting surface will be described below with reference to FIG.
　図５に示すように入射した光の一部である光線５７ａは導光板４５内を進む。光線５７ａは偏向面４１に設けられた溝４７ａにて反射する。溝４７ａは蛇行しているので光線５７ａは溝４７ａによって拡散する。さらに光線５７ａは内部反射面４２で再び反射する。内部反射面４２に設けられた凸条によって光線５７ａはさらに拡散する。 As shown in FIG. 5, a light beam 57 a that is part of the incident light travels through the light guide plate 45. The light beam 57 a is reflected by a groove 47 a provided on the deflection surface 41. Since the groove 47a meanders, the light beam 57a is diffused by the groove 47a. Further, the light beam 57 a is reflected again by the internal reflection surface 42. The light rays 57a are further diffused by the ridges provided on the internal reflection surface.
　図５に示すように光線５７ａは再び偏向面４１に戻る。光線５７ａは偏向面４１から外界に向けて出射する。ここで光線５７ａが通過する溝４７ｃには傾斜があることから、光線５７ａが偏向面４１で全反射して再び導光板４５の中央に戻ることが軽減される。光線５７ａは出射面の法線方向に対して高角度、概ね６０～７０度の方向に向かって進む。図中では－Ｚ方向に対し６０～７０度を成す方向に向かって進む。 As shown in FIG. 5, the light beam 57a returns to the deflecting surface 41 again. The light beam 57a is emitted from the deflecting surface 41 toward the outside. Here, since the groove 47c through which the light beam 57a passes is inclined, it is reduced that the light beam 57a is totally reflected by the deflecting surface 41 and returns to the center of the light guide plate 45 again. The light beam 57a travels in a direction at a high angle, approximately 60 to 70 degrees, with respect to the normal direction of the exit surface. In the figure, it proceeds in the direction of 60 to 70 degrees with respect to the −Z direction.
　また、図５に示すように入射した光の他の一部である光線５７ｂは導光板４５内を進む。光線５７ｂは内部反射面４２で反射することなく内部反射面４２から出射する。光線５７ｂは、さらに反射シート５０の有する反射面４９で反射する。光線５７ｂが乱反射するように、反射面４９は所定の拡散反射率を有していてもよい。光線５７ｂは内部反射面４２に入射する。光線５７ｂは導光板４５内に再進入する。光線５７ｂは偏向面４１から外界に向けて出射する。光線５７ａは出射面の法線方向に対して低角度、概ね２０～３０度の方向に向かって進む。図中では－Ｚ方向に対して２０～３０度を成す方向に向かって進む。 Further, as shown in FIG. 5, the light beam 57 b which is another part of the incident light travels in the light guide plate 45. The light beam 57 b is emitted from the internal reflection surface 42 without being reflected by the internal reflection surface 42. The light beam 57 b is further reflected by the reflection surface 49 of the reflection sheet 50. The reflection surface 49 may have a predetermined diffuse reflectance so that the light beam 57b is irregularly reflected. The light beam 57 b is incident on the internal reflection surface 42. The light beam 57 b reenters the light guide plate 45. The light beam 57b is emitted from the deflecting surface 41 toward the outside. The light beam 57a travels at a low angle with respect to the normal direction of the exit surface, generally in the direction of 20 to 30 degrees. In the figure, it proceeds in the direction of 20 to 30 degrees with respect to the -Z direction.
　図５に示す導光装置４０はさらに光を散乱させるための拡散板（diffusion plate）５５を備えていてもよい。拡散板５５は偏向面４１を有する下底面と対向する。拡散板５５は偏向面４１から出射する光線５７ａ及びｂを含む光を散乱させる。 The light guide device 40 shown in FIG. 5 may further include a diffusion plate 55 for scattering light. The diffusion plate 55 is opposed to the lower bottom surface having the deflection surface 41. The diffuser plate 55 scatters light including light rays 57 a and b emitted from the deflection surface 41.
　図５に示す拡散板５５の表面も裏面も鏡面又はシボ面とすることができ、特に制限されない。拡散板５５の全光線透過率（T.T）は９０％以上であることが好ましい。ヘイズ値（Haze）は７０％以上であることが好ましい。 The front and back surfaces of the diffusing plate 55 shown in FIG. 5 can be mirror surfaces or textured surfaces, and are not particularly limited. The total light transmittance (T.T) of the diffusion plate 55 is preferably 90% or more. The haze value (Haze) is preferably 70% or more.
　図５に示す拡散板５５は光の拡散性の無い透明な保護板に置き換えることが出来る。かかる保護板は偏向面４１から出射する光を透過する。保護板は偏向面４１が外的要因により損傷することを防止する。拡散板５５が保護板として機能してもよい。拡散板５５又は保護板の厚さは０．１～３ｍｍであることが好ましい。 5 can be replaced with a transparent protective plate having no light diffusibility. Such a protective plate transmits light emitted from the deflecting surface 41. The protective plate prevents the deflection surface 41 from being damaged by an external factor. The diffusion plate 55 may function as a protection plate. The thickness of the diffusion plate 55 or the protection plate is preferably 0.1 to 3 mm.
　本実施形態では少なくとも図１～５に示される光学要素の形状設計と、偏向面４１、内部反射面４２及び反射面４９の位置関係とに基づいて、導光装置４０が所望の配光特性を発揮する。以下の実施例の第１部ではこれらの光学的要素と配光特性との関係を説明する。 In the present embodiment, the light guide device 40 has a desired light distribution characteristic based on at least the shape design of the optical element shown in FIGS. Demonstrate. In the first part of the following examples, the relationship between these optical elements and the light distribution characteristics will be described.
　また本実施形態では係る配光特性により、滑らかな照度分布変化を実現することができる。以下の実施例の第２部では上記の光学的要素と照度分布変化との関係を説明する。 Further, in the present embodiment, a smooth illuminance distribution change can be realized by the light distribution characteristics. In the second part of the following example, the relationship between the optical element and the change in illuminance distribution will be described.
　なお上述した図５はモデルであり、全ての光の経路を表しているわけではない。このため偏向面４１で部分反射する光やその他の光の存在も考慮すれば、光が図５に表されない様々な経路を辿っていることで上述の配光特性及び照度分布変化を実現していることは容易に予想される。 Note that FIG. 5 described above is a model and does not represent all light paths. Therefore, considering the presence of light partially reflected by the deflecting surface 41 and other light, the light distribution characteristics and the illuminance distribution change described above are realized by the light following various paths not shown in FIG. It is easily expected to be.
　例えば図５では、溝４７ａ－ｃの斜面のうち受光面から遠い側の斜面に一見特別な働きが無いように見える。しかしながら、かかる斜面にも働きがあり、またかかる斜面の設計も本実施形態の一態様に含まれることを実施例の第３部にて説明する。 For example, in FIG. 5, it seems that there is no special function on the slopes of the grooves 47a-c far from the light receiving surface. However, it is explained in the third part of the example that such a slope also works and that the design of the slope is also included in one aspect of the present embodiment.
［第１部］　光学的要素と配光特性との関係 [Part 1] Relationship between optical elements and light distribution characteristics
　各実施例及び比較例においてはまず所定の導光板を準備した。必要に応じてかかる導光板の内部反射面又は偏向面を反射シートで覆うことで導光装置を得た。さらに導光装置と点光源群とを組み合わせて面状発光モジュールを得た。光学的な測定は面状発光モジュールに対して行った。 In each example and comparative example, a predetermined light guide plate was first prepared. A light guide device was obtained by covering the internal reflection surface or the deflection surface of the light guide plate with a reflection sheet as necessary. Furthermore, the planar light emitting module was obtained by combining the light guide device and the point light source group. Optical measurement was performed on the planar light emitting module.
　以下においては一連の作業を含む実施の態様を実施例又は比較例と呼ぶものする。したがって実施例又は比較例の実施によって得られた「導光板」、「導光装置」、及び「面状発光モジュール」を、実施例又は比較例の「導光板」、実施例又は比較例の「導光装置」、実施例又は比較例の「面状発光モジュール」と呼ぶものする。 Hereinafter, embodiments including a series of operations will be referred to as examples or comparative examples. Therefore, the “light guide plate”, “light guide device”, and “planar light emitting module” obtained by the implementation of the example or the comparative example are replaced with the “light guide plate” of the example or the comparative example, the “light guide plate” of the example or the comparative example. It will be referred to as “light guide device”, “planar light emitting module” in Examples or Comparative Examples.
　図６には実施例１の面状発光モジュール７０が示されている。面状発光モジュール７０の備える光学的要素を以下に説明する。面状発光モジュール７０は、導光板６５及び反射シート５０からなる導光装置６０を備える。図中には導光板６５の下底面６１が示されている。反射シート５０は下底面６１の裏側に設置されている。反射シート５０の反射面は９０％以上の拡散反射率を有する。実施例１において反射シート５０は拡散タイプの反射シートである。下底面６１は偏向面４１を有する。 FIG. 6 shows the planar light emitting module 70 of the first embodiment. The optical elements included in the planar light emitting module 70 will be described below. The planar light emitting module 70 includes a light guide device 60 including a light guide plate 65 and a reflection sheet 50. In the figure, a lower bottom surface 61 of the light guide plate 65 is shown. The reflection sheet 50 is installed on the back side of the lower bottom surface 61. The reflection surface of the reflection sheet 50 has a diffuse reflectance of 90% or more. In Example 1, the reflection sheet 50 is a diffusion type reflection sheet. The lower bottom surface 61 has a deflection surface 41.
　図６に示す導光板６５は図１に示す導光板４５と同様の構成を有する。導光板６５はさらに以下の特徴を有する。偏向面４１は下底面６１の中央に位置する。下底面６１は偏向面４１を取り囲む滑面６３を有する。端面４３ａと偏向面４１との間には滑面６３が位置する。 The light guide plate 65 shown in FIG. 6 has the same configuration as the light guide plate 45 shown in FIG. The light guide plate 65 further has the following characteristics. The deflection surface 41 is located at the center of the lower bottom surface 61. The lower bottom surface 61 has a smooth surface 63 surrounding the deflection surface 41. A smooth surface 63 is located between the end surface 43 a and the deflection surface 41.
　なお図６の下段に示すように導光板６５はさらに下底面６１の裏側にある上底面を有する。かかる上底面は図中での描画が省略されている。かかる上底面は内部反射面が滑面で取り囲まれているものでもよい。なお、当該実施例および比較例においては、端面４３ａと内部反射面との間および端面４３ｂと内部反射面との間に滑面がない。すなわち、端面４３ａから端面４３ｂまで内部反射面を有する。 As shown in the lower part of FIG. 6, the light guide plate 65 further has an upper bottom surface behind the lower bottom surface 61. The upper bottom surface is not shown in the drawing. The upper bottom surface may have an internal reflection surface surrounded by a smooth surface. In the examples and comparative examples, there is no smooth surface between the end surface 43a and the internal reflection surface and between the end surface 43b and the internal reflection surface. That is, it has an internal reflection surface from the end surface 43a to the end surface 43b.
　図６に示す面状発光モジュール７０はさらに点光源群６６を備える。受光面をなしている端面４３ａは点光源群６６と対向する。点光源群６６は所定の間隔で列をなす複数の点光源を有する。点光源の個数は限定されない。点光源はＬＥＤが好ましい。本実施例では白色ＬＥＤを点光源として利用した。点光源の成す列の方向は偏向面４１と平行である。 The planar light emitting module 70 shown in FIG. 6 further includes a point light source group 66. An end face 43 a forming a light receiving surface faces the point light source group 66. The point light source group 66 has a plurality of point light sources arranged in rows at predetermined intervals. The number of point light sources is not limited. The point light source is preferably an LED. In this embodiment, a white LED is used as a point light source. The direction of the row formed by the point light sources is parallel to the deflection surface 41.
　図２に戻る。図２を参照しつつ実施例１の導光板の備える偏向面に設けられた溝の寸法を説明する。溝のベースラインの蛇行の単位長Ｕｌは０．５ｍｍである。溝のベースラインの蛇行の振幅は７０μｍ（０．０７ｍｍ）である。α値は０．１４である。溝のベースライン間の間隔は６２μｍである。図６に示す偏向面４１内には６６２本の溝が隙間なく設けられている。溝同士の位相は一致している。 Return to Figure 2. The dimension of the groove | channel provided in the deflection surface with which the light-guide plate of Example 1 is provided is demonstrated referring FIG. The unit length Ul of the meandering of the groove base line is 0.5 mm. The amplitude of the meandering of the groove baseline is 70 μm (0.07 mm). The α value is 0.14. The spacing between the groove baselines is 62 μm. In the deflection surface 41 shown in FIG. 6, 662 grooves are provided without gaps. The phases of the grooves are the same.
　次に図３を参照しつつ実施例１の導光板の備える偏向面に設けられた溝の断面における寸法を説明する。上底Ｂｕの幅は０μｍである。すなわち溝の断面の輪郭線は三角形である。下底Ｂｌの幅は５５μｍである。深さＤｐは７μｍである。斜度Ｏｂ１及び斜度Ｏｂ２はいずれも等しい。すなわち溝の断面の輪郭線は二等辺三角形である。これらの角度は１５度である。頂角Ｖは１５０度である。溝の側部は、側部Ｌａ１及び２に示すように直線状である。 Next, referring to FIG. 3, the dimensions of the cross section of the groove provided on the deflection surface provided in the light guide plate of Example 1 will be described. The width of the upper base Bu is 0 μm. That is, the outline of the cross section of the groove is a triangle. The width of the lower base Bl is 55 μm. The depth Dp is 7 μm. Both the slope Ob1 and the slope Ob2 are equal. That is, the outline of the cross section of the groove is an isosceles triangle. These angles are 15 degrees. The apex angle V is 150 degrees. The side portions of the groove are linear as shown by the side portions La1 and La2.
　次に図１及び４を参照しつつ、実施例１の導光板の備える内部反射面に設けられた凸条の断面における寸法を説明する。凸条の断面の輪郭は円弧からなる。凸条はレンチキュラーレンズである。以下、断面の輪郭が円弧である凸条を特にレンチキュラー（Lenticular）と呼ぶ場合がある。アスペクト比は２０％である。凸条の高さは１２．５μｍである。 Next, with reference to FIGS. 1 and 4, the dimensions of the cross-section of the ridges provided on the internal reflection surface of the light guide plate of Example 1 will be described. The contour of the cross section of the ridge is an arc. The ridge is a lenticular lens. Hereinafter, a ridge having a circular cross-sectional outline may be particularly referred to as a lenticular. The aspect ratio is 20%. The height of the ridge is 12.5 μm.
　図６に示すように面状発光モジュール７０はさらに反射材６７を有する。反射材６７は反射シート５０とは向きの異なる部材である。反射材６７の有する反射面は端面４３ｂに対向する。反射材６７の有する反射面では光は乱反射する。 As shown in FIG. 6, the planar light emitting module 70 further includes a reflector 67. The reflective material 67 is a member having a different direction from the reflective sheet 50. The reflective surface of the reflective material 67 faces the end surface 43b. The light is irregularly reflected on the reflecting surface of the reflector 67.
　図６に示す点光源群６６を点灯し、実施例１の面状発光モジュールの配光特性の測定を行った。結果を図７及び８に示した。配光特性の測定の態様は他の実施例及び比較例において同様である。 The point light source group 66 shown in FIG. 6 was turned on, and the light distribution characteristics of the planar light emitting module of Example 1 were measured. The results are shown in FIGS. The mode of measuring the light distribution characteristics is the same in the other examples and comparative examples.
　図７には実施例１の面状発光モジュールのゴニオマップが示されている。ゴニオマップは等光度グラフとも呼ばれることがある。Ｘ軸及びＹ軸は図１に示すＸ軸及びＹ軸と対応している。ゴニオマップの上方が図１に示す出射方向Ｅｘ１に対応している。中心の０度は図１に示す－Ｚ方向の光度を表している。 FIG. 7 shows a gonio map of the planar light emitting module of Example 1. A gonio map is sometimes called an isoluminous graph. The X axis and the Y axis correspond to the X axis and the Y axis shown in FIG. The upper part of the gonio map corresponds to the emission direction Ex1 shown in FIG. The 0 degree at the center represents the luminous intensity in the −Z direction shown in FIG.
　図７に示す領域Ｇ１～Ｇ８はそれぞれ光束1,000 lmあたりの光度（cd）の水準が等しい領域を表す。各領域の光度の範囲は次の通りである。G1(0.0-67.5)、G2(67.5-135.0)、G3(135.0-202.5)、G4(202.5-270.0)、G5(270.0-337.5)、G6(337.5-405.0)、G7(405.0-472.5)、G8(472.5-540.0)。 7 represent regions where the level of luminous intensity (cd) per 1,000 μm of luminous flux is equal. The range of luminous intensity in each region is as follows. G1 (0.0-67.5), G2 (67.5-135.0), G3 (135.0-202.5), G4 (202.5-270.0), G5 (270.0-337.5), G6 (337.5-405.0), G7 (405.0-472.5), G8 (472.5-540.0).
　図８には実施例１の面状発光モジュールの配光分布グラフが示されている。中心の０度は図１に示す－Ｚ方向の光度を表している。配光曲線Ｄｘに関しては－９０度が図１に示す－Ｘ方向を、＋９０度が図１に示す＋Ｘ方向を表している。配光曲線Ｄｙに関しては－９０度が図１に示す－Ｙ方向を、９０度が図１に示す＋Ｙ方向を表している。グラフの見方は以下同様である。 FIG. 8 shows a light distribution graph of the planar light emitting module of Example 1. The 0 degree at the center represents the luminous intensity in the −Z direction shown in FIG. Regarding the light distribution curve Dx, −90 degrees represents the −X direction shown in FIG. 1, and +90 degrees represents the + X direction shown in FIG. Regarding the light distribution curve Dy, −90 degrees represents the −Y direction shown in FIG. 1, and 90 degrees represents the + Y direction shown in FIG. The way to read the graph is the same below.
　図７及び８に示す結果より、実施例１の面状発光モジュールより出射する光が＋Ｙ方向に偏ってことが分かる。また＋Ｙ方向の６０－７０度付近の光度が最も強くなっていることが分かる。また０度付近から、６０－７０度付近まで緩やかに光度が変化することが分かる。また＋／－Ｘ方向に対しては穏やかに光が拡散していることが分かる。 7 and 8 show that the light emitted from the planar light emitting module of Example 1 is biased in the + Y direction. It can also be seen that the light intensity around 60-70 degrees in the + Y direction is the strongest. It can also be seen that the luminous intensity changes gradually from around 0 degrees to around 60-70 degrees. It can also be seen that light diffuses gently in the +/− X direction.
　次に図９に示す比較例１を用いて、実施例において内部反射面４２に対向する反射シートを用いたことの意義について説明する。先に図５を示しつつ、内部反射面４２で反射する光線５７ａと、内部反射面４２から出射する光線５７ｂとを説明した。したがって内部反射面での反射する光と内部反射面からの出射する光の大小関係は本実施例において重要である。 Next, the significance of using the reflection sheet facing the internal reflection surface 42 in the example will be described using Comparative Example 1 shown in FIG. The light beam 57a reflected by the internal reflection surface 42 and the light beam 57b emitted from the internal reflection surface 42 have been described above with reference to FIG. Therefore, the magnitude relationship between the light reflected from the internal reflection surface and the light emitted from the internal reflection surface is important in this embodiment.
　図９に示す比較例１では、実施例１でも用いた導光板６５と同等の導光板を用いた。ただし、内部反射面４２に対向する反射シート５０を用いなかった。図中の導光板６５では説明の便宜上、偏向面４１及び内部反射面４２の周囲にある滑面の描画が省略されている。反射材６７は用いた。 In Comparative Example 1 shown in FIG. 9, a light guide plate equivalent to the light guide plate 65 used in Example 1 was used. However, the reflection sheet 50 facing the internal reflection surface 42 was not used. In the light guide plate 65 in the drawing, the drawing of the smooth surface around the deflection surface 41 and the internal reflection surface 42 is omitted for convenience of explanation. The reflective material 67 was used.
　図９に示す光束５８ａ～ｃは点光源に由来する光束を模式的に表したものである。光束５８ａ～ｃで表される光は導光方向Ｇｕに沿って導かれる。偏向面４１の働きにより、光は向きを変える。光の一部は内部反射面４２で反射したのち、偏向面４１から出射方向Ｅｘ２に沿って出射する。Ｅｘ２は偏向面４１の側の出射方向のうち全方向を表す。 The light beams 58a to 58c shown in FIG. 9 schematically represent a light beam derived from a point light source. The light represented by the light beams 58a to 58c is guided along the light guide direction Gu. The direction of the light is changed by the action of the deflection surface 41. A part of the light is reflected by the internal reflection surface 42 and then emitted from the deflection surface 41 along the emission direction Ex2. Ex2 represents all directions in the emission direction on the deflection surface 41 side.
　図９に示すように光の一部は内部反射面４２から、出射方向Ｂｃ１に沿って出射する。出射方向Ｂｃ１は内部反射面４２の側の出射方向のうち全方向を表す。出射方向Ｅｘ２側の光束と、出射方向Ｂｃ１側の光束を比較すると出射方向Ｂｃ１側の光束の方が多い。 As shown in FIG. 9, a part of the light is emitted from the internal reflection surface 42 along the emission direction Bc1. The emission direction Bc1 represents all directions among the emission directions on the internal reflection surface 42 side. When the luminous flux on the emission direction Ex2 side and the luminous flux on the emission direction Bc1 side are compared, the luminous flux on the emission direction Bc1 side is larger.
　上述の実施例１では、図９に示すように反射シート５０を設けることで、内部反射面４２から出射する光を、反射シート５０の反射面で反射する。これにより、多くの光を偏向面４１側から出射させることができる。 In Example 1 described above, by providing the reflection sheet 50 as shown in FIG. 9, the light emitted from the internal reflection surface 42 is reflected by the reflection surface of the reflection sheet 50. Thereby, a lot of light can be emitted from the deflection surface 41 side.
　図９に示す反射シート６８は、反射シート５０と同等の反射シートである。ただし、反射シート６８の反射面は偏向面４１に対向している。比較例２では、このように反射シートが偏向面側に配置された導光装置を用いた。これにより、偏向面側から出射された光は、反射シートで反射されて、偏向面から導光板内部に再入射して、内部反射面４２の側から出射する。 9 is a reflective sheet equivalent to the reflective sheet 50. The reflective sheet 68 shown in FIG. However, the reflection surface of the reflection sheet 68 faces the deflection surface 41. In Comparative Example 2, a light guide device in which the reflection sheet is arranged on the deflection surface side in this way was used. Thereby, the light emitted from the deflection surface side is reflected by the reflection sheet, reenters the light guide plate from the deflection surface, and exits from the internal reflection surface 42 side.
　図１０には比較例２の導光装置７５が示されている。比較例２の導光装置７５は偏向面４１（図１）に換えて偏向面７１を有する。偏向面７１は実施例１の導光板と異なり、直線状の溝７７ａ－ｄを備える。また導光装置７５は内部反射面４２の側に設けられた反射シートを備えない。一方で、導光装置７５は偏向面側に設けられた反射シート６８を備える。それ以外の特徴は実施例１の導光装置と同じである。 FIG. 10 shows the light guide device 75 of the second comparative example. The light guide device 75 of the comparative example 2 has a deflection surface 71 instead of the deflection surface 41 (FIG. 1). Unlike the light guide plate of the first embodiment, the deflection surface 71 includes linear grooves 77a-d. Further, the light guide device 75 does not include a reflection sheet provided on the internal reflection surface 42 side. On the other hand, the light guide device 75 includes a reflection sheet 68 provided on the deflection surface side. Other features are the same as those of the light guide device of the first embodiment.
　図１０に示す導光装置７５において、導光板４５内で導かれた光は出射方向Ｂｃ２にそって出射する。出射方向Ｂｃ２は端面４３ａの成す受光面から遠い側に向かう方向である。 In the light guide device 75 shown in FIG. 10, the light guided in the light guide plate 45 is emitted along the emission direction Bc2. The emission direction Bc2 is a direction toward the side far from the light receiving surface formed by the end face 43a.
　本比較例２では図１０に示す導光装置７５を用いて面状発光モジュールを実施例１と同様に作製した。比較例２の面状発光モジュールの配光特性の測定を行った。 In Comparative Example 2, a planar light emitting module was produced in the same manner as in Example 1 using the light guide device 75 shown in FIG. The light distribution characteristics of the planar light emitting module of Comparative Example 2 were measured.
　図１１には比較例２の面状発光モジュールの配光分布グラフが示されている。比較例２の面状発光モジュールより出射する光もまた＋Ｙ方向に偏っていることが分かる。しかしながら、＋Ｙ方向側の＋Ｚ方向より４０－６０度傾いた付近の光度が最も強くなっていた。また０度から２０度付近では光度が弱いが、３０度付近から急激に光度が強くなることが分かる。なお＋／－Ｘ方向に対しては穏やかに光が拡散していた。 FIG. 11 shows a light distribution graph of the planar light emitting module of Comparative Example 2. It can be seen that the light emitted from the planar light emitting module of Comparative Example 2 is also biased in the + Y direction. However, the light intensity in the vicinity of 40-60 degrees inclined from the + Z direction on the + Y direction side was the strongest. It can also be seen that the luminous intensity is weak at around 0 to 20 degrees, but the luminous intensity increases rapidly from around 30 degrees. The light diffused gently in the +/− X direction.
　次に、面状発光モジュールの発光特性が、上述した溝の平均斜度又は頂角Ｖに依存するか否かを調べた。以下の通り、溝の平均斜度の異なる面状発光モジュールを用意し、それらの発光特性を測定した。 Next, it was examined whether or not the light emission characteristics of the planar light emitting module depend on the average slope or apex angle V of the groove. As described below, planar light emitting modules having different average slopes of the grooves were prepared, and their light emission characteristics were measured.
　図１２には比較例３の面状発光モジュールの配光分布グラフが示されている。溝の平均斜度は２５度である。頂角Ｖは１３０度である。溝のベースライン間の間隔は４０μｍである。＋Ｚ方向より＋Ｙ方向側に６０度傾いた付近で光度が低下していた。このため、実施例１とは異なり、２つの顕著な光度ピークが形成されていた。 FIG. 12 shows a light distribution graph of the planar light emitting module of Comparative Example 3. The average inclination of the grooves is 25 degrees. The apex angle V is 130 degrees. The spacing between the groove baselines is 40 μm. The light intensity decreased in the vicinity of 60 ° tilted to the + Y direction side from the + Z direction. For this reason, unlike Example 1, two remarkable light intensity peaks were formed.
　図１３には比較例４の面状発光モジュールの配光分布グラフが示されている。溝の平均斜度は２２．５度である。頂角Ｖは１３５度である。溝のベースライン間の間隔は４５μｍである。＋Ｚ方向より＋Ｙ方向側に６０度傾いた付近で光度が低下していた。このため、実施例１とは異なり、２つの顕著な光度ピークが形成されていた。 FIG. 13 shows a light distribution graph of the planar light emitting module of Comparative Example 4. The average slope of the grooves is 22.5 degrees. The apex angle V is 135 degrees. The spacing between the groove baselines is 45 μm. The light intensity decreased in the vicinity of 60 ° tilted to the + Y direction side from the + Z direction. For this reason, unlike Example 1, two remarkable light intensity peaks were formed.
　図１４には実施例２の面状発光モジュールの配光分布グラフが示されている。溝の平均斜度は２０度である。頂角Ｖは１４０度である。溝のベースライン間の間隔は５０μｍである。＋Ｚ方向より＋Ｙ方向側に６０度傾いた付近で若干光度が低下していたが、６０－７０度付近まで緩やかに光度が変化することが分かる。 FIG. 14 shows a light distribution graph of the planar light emitting module of Example 2. The average slope of the grooves is 20 degrees. The apex angle V is 140 degrees. The spacing between the groove baselines is 50 μm. It can be seen that the light intensity slightly decreased in the vicinity of 60 ° tilted to the + Y direction side from the + Z direction, but gradually changes to 60-70 °.
　図１５には実施例３の面状発光モジュールの配光分布グラフが示されている。溝の平均斜度は１７．５度である。頂角Ｖは１４５度である。溝のベースライン間の間隔は５５μｍである。＋Ｚ方向より＋Ｙ方向側に６５度傾いた付近で若干光度が低下していた。しかしながら６０－７０度付近まで緩やかに光度が変化することが分かる。 FIG. 15 shows a light distribution graph of the planar light emitting module of Example 3. The average slope of the grooves is 17.5 degrees. The apex angle V is 145 degrees. The spacing between the groove baselines is 55 μm. The light intensity slightly decreased in the vicinity of 65 ° tilted to the + Y direction side from the + Z direction. However, it can be seen that the luminous intensity changes gradually to around 60-70 degrees.
　図１６には実施例１の面状発光モジュールの配光分布グラフが示されている。先に述べたとおり溝の平均斜度は１５度である。頂角Ｖは１５０度である。溝のベースライン間の間隔は６２μｍである。他の実施例２及び３に比べても、＋Ｚ方向より＋Ｙ方向側に６０－７０度傾いた付近の光度が強く、またこの付近での光度の低下が見られなかった。 FIG. 16 shows a light distribution graph of the planar light emitting module of Example 1. As described above, the average inclination of the grooves is 15 degrees. The apex angle V is 150 degrees. The spacing between the groove baselines is 62 μm. Compared with the other Examples 2 and 3, the luminous intensity in the vicinity of 60-70 degrees inclined to the + Y direction side from the + Z direction was strong, and no decrease in luminous intensity was observed in this vicinity.
　図１７には実施例４の面状発光モジュールの配光分布グラフが示されている。溝の平均斜度は１２．５度である。頂角Ｖは１５５度である。溝のベースライン間の間隔は７３μｍである。実施例１と同様に＋Ｚ方向より＋Ｙ方向側に６０－７０度傾いた付近の光度が強く、またこの付近での光度の低下が見られなかった。－Ｙ方向の光度が実施例１よりもやや高まっていた。 FIG. 17 shows a light distribution graph of the planar light emitting module of Example 4. The average slope of the grooves is 12.5 degrees. The apex angle V is 155 degrees. The spacing between the groove base lines is 73 μm. Similar to Example 1, the light intensity in the vicinity of 60-70 degrees inclined to the + Y direction side from the + Z direction was strong, and no decrease in light intensity was observed in this vicinity. The intensity in the −Y direction was slightly higher than in Example 1.
　図１８には比較例５の面状発光モジュールの配光分布グラフが示されている。溝の平均斜度は１０度である。頂角Ｖは１６０度である。溝のベースライン間の間隔は９０μｍである。－Ｙ方向側の光度が他の実施例よりも高まっていた。また３０度付近まで光度の低下が見られた。 FIG. 18 shows a light distribution graph of the planar light emitting module of Comparative Example 5. The average inclination of the grooves is 10 degrees. The apex angle V is 160 degrees. The spacing between the groove baselines is 90 μm. The light intensity on the -Y direction side was higher than in the other examples. In addition, a decrease in luminous intensity was observed up to around 30 degrees.
　実施例と比較例との面状発光モジュールの配光特性の比較より、平均斜度が１２．５度～２０度であることが好ましいことが分かった。また頂角Ｖが１４０度から１５５度であることが好ましいことが分かった。平均斜度又は頂角Ｖがかかる範囲にあることで出射面の法線方向に対して低角度の方向に一定量の光が出射しつつ、高角度の方向に至るまで様々な角度でむらなく光が出射することが分かった。 From the comparison of the light distribution characteristics of the planar light emitting modules between the example and the comparative example, it was found that the average inclination is preferably 12.5 degrees to 20 degrees. It was also found that the apex angle V is preferably 140 to 155 degrees. When the average inclination or the apex angle V is in such a range, a certain amount of light is emitted in a direction at a low angle with respect to the normal direction of the emission surface, and evenly at various angles until reaching a high angle direction. It was found that light was emitted.
　図１９に溝の頂角Ｖと出射光束との関係を表す。平均斜度が大きいほど、又は頂角Ｖが小さいほど出射する光の量が大きいことが分かった。また平均斜度が１２．５度以上、又は頂角Ｖが１５５度以下となることで出射光束の量を十分な水準に保てることが分かった。最も出射光束が低下した実施例４においても、比較例３の出射光束の９割以上の出射光束を得られた。 FIG. 19 shows the relationship between the apex angle V of the groove and the emitted light beam. It was found that the larger the average slope or the smaller the apex angle V, the larger the amount of light emitted. It was also found that the amount of emitted light beam can be kept at a sufficient level when the average inclination is 12.5 degrees or more or the apex angle V is 155 degrees or less. Even in Example 4 where the emitted light flux was the lowest, 90% or more of the emitted light flux of Comparative Example 3 was obtained.
［第２部］　光学的要素と照度分布変化との関係 [Part 2] Relationship between optical elements and changes in illuminance distribution
　次に導光装置にかかる光学的要素と照度分布変化との関係を調べた。図２０に示すように実施例１の導光装置６０を被照射面８０と対向するように設置した。偏向面４１は被照射面８０に対向する。偏向面４１の周囲にある滑面は描画が省略されている（図６参照）。出射方向Ｅｘ１に沿って進む光は拡散しながら被照射面８０に向かって進む。かかる光は被照射面８０を照らす。 Next, the relationship between the optical element applied to the light guide device and the change in illuminance distribution was examined. As shown in FIG. 20, the light guide device 60 of Example 1 was installed so as to face the irradiated surface 80. The deflection surface 41 faces the irradiated surface 80. Drawing of the smooth surface around the deflection surface 41 is omitted (see FIG. 6). The light traveling along the emission direction Ex1 travels toward the irradiated surface 80 while diffusing. Such light illuminates the illuminated surface 80.
　図２０には示されていない点光源群を点灯して入射方向Ｉｎより導光装置６０に光を通した。被照射面８０における照度を測定した。偏向面４１と被照射面８０との距離は６０ｃｍとした。 20 A point light source group not shown in FIG. 20 was turned on and light was transmitted through the light guide device 60 from the incident direction In. The illuminance on the irradiated surface 80 was measured. The distance between the deflection surface 41 and the irradiated surface 80 was 60 cm.
　図２０に示す端面４３ａの中心の直下にある被照射面８０上の点を基準点Ｒｅとした。て、基準点Ｒｅより＋Ｙ方向及び－Ｘ方向における照度の測定値より図２１及び２２のグラフを得た。なお導光板及び偏光板の寸法は図６の寸法ａ－ｆに示した通りである。 A point on the irradiated surface 80 immediately below the center of the end face 43a shown in FIG. Thus, the graphs of FIGS. 21 and 22 were obtained from the measured values of illuminance in the + Y direction and the −X direction from the reference point Re. The dimensions of the light guide plate and the polarizing plate are as shown in dimensions af of FIG.
　図２１及び２２のグラフの横軸は基準点Ｒｅ（図２０）からの距離を示す。グラフの縦軸は照度比を表す。すなわち各面状発光モジュールごとに最大の照度を得た距離における照度を１として各距離における照度の値を比で表したものである。以下、同様とする。 21 and 22 indicate the distance from the reference point Re (FIG. 20). The vertical axis of the graph represents the illuminance ratio. That is, the illuminance at each distance where the maximum illuminance is obtained for each planar light emitting module is 1, and the illuminance value at each distance is expressed as a ratio. The same shall apply hereinafter.
　図２１及び２２を用いて凸条及び溝の蛇行の奏する効果を説明する。図２１及び２２には実施例１（Ｗｏ１）並びに比較例６（Ｃｏ６）及び７（Ｃｏ７）の照度分布を表すグラフが示されている。以下、実施例（Working example）を略号Ｗｏで表す。また比較例（Comparative example）を略号Ｃｏで表す。図２１は＋Ｙ方向である。図２２は－Ｘ方向である。 21 and 22 will be used to explain the effect of the ridges and grooves meandering. 21 and 22 are graphs showing the illuminance distribution of Example 1 (Wo1) and Comparative Examples 6 (Co6) and 7 (Co7). Hereinafter, an example (Working example) is represented by the abbreviation Wo. In addition, a comparative example is represented by the abbreviation Co. FIG. 21 shows the + Y direction. FIG. 22 shows the −X direction.
　比較例６及び７と実施例１とは以下の点が異なる。比較例６の導光板には蛇行する溝（Meander）の代わりに直線状の溝（Straight）が設けられている。比較例７は内部反射面に凸条が設けられていない。したがって内部反射面が鏡面（Specular surface）となっている。各実施例及び比較例ともに頂角Ｖは１５０度である（Ｖ１５０）。 Comparative Examples 6 and 7 and Example 1 are different in the following points. The light guide plate of Comparative Example 6 is provided with straight grooves (Straight) instead of meandering grooves (Meander). In Comparative Example 7, no protrusions are provided on the internal reflection surface. Therefore, the internal reflection surface is a specular surface. In each example and comparative example, the apex angle V is 150 degrees (V150).
　図２１に示すように比較例６には基準点からの距離４００－５００ｍｍ付近に照度の極大点Ｍａ１が見られた。比較例７には基準点からの距離１，０００ｍｍ付近に照度の極大点Ｍａ２が見られた。これらの極大点は被照射面上で輝線として視認できるものであった。 As shown in FIG. 21, in Comparative Example 6, an illuminance maximum point Ma1 was found in the vicinity of a distance of 400 to 500 mm from the reference point. In Comparative Example 7, a local maximum point Ma2 of illuminance was observed near a distance of 1,000 mm from the reference point. These maximum points were visible as bright lines on the irradiated surface.
　これに対して実施例１では、図２０に示すように偏向面４１の法線方向に対して低角度の方向にある被照射面、すなわち近傍の被照射面を明るく照らしつつ、高角度の方向にある被照射面、すなわち遠方の被照射面まで滑らかに照度分布を変化させることができた。これらの効果は凸条の存在及び溝の蛇行に依拠すると考えられる。 On the other hand, in the first embodiment, as shown in FIG. 20, the illuminated surface in a low angle direction with respect to the normal direction of the deflecting surface 41, that is, the illuminated surface in the vicinity is brightly illuminated, and the high angle direction It was possible to smoothly change the illuminance distribution up to the irradiated surface in FIG. These effects are thought to depend on the presence of ridges and meandering grooves.
　図２２に示すようにＸ軸方向の照度分布には特段の差が見られなかった。 As shown in FIG. 22, no particular difference was observed in the illuminance distribution in the X-axis direction.
　図２３及び２４を用いて溝の側部の斜度及び反射シートの設置個所の奏する効果を説明する。図２３及び２４には実施例４、１及び２並びに比較例３、８及び２の照度分布を表すグラフが示されている。図２３は＋Ｙ方向である。図２４は－Ｘ方向である。 23 and 24, the effect of the inclination of the side of the groove and the location where the reflection sheet is installed will be described. 23 and 24 show graphs representing the illuminance distributions of Examples 4, 1, and 2 and Comparative Examples 3, 8, and 2. FIG. FIG. 23 shows the + Y direction. FIG. 24 shows the −X direction.
　比較例８では比較例２と同様に反射シートが偏向面側に設けられている（Reversed、図１０）。比較例２には頂角Ｖが１５０度の溝が偏向面に設けられている。これに対して比較例８では頂角Ｖが１３０の溝が偏向面に設けられている。さらに、いずれの溝も実施例１と異なり直線状（Straight）である。 In Comparative Example 8, a reflective sheet is provided on the deflection surface side as in Comparative Example 2 (Reversed, FIG. 10). In Comparative Example 2, a groove having an apex angle V of 150 degrees is provided on the deflection surface. On the other hand, in Comparative Example 8, a groove having an apex angle V of 130 is provided on the deflection surface. Further, each of the grooves is straight (Straight) unlike the first embodiment.
　図２３に示すように比較例３及び８では距離が５００ｍｍから１０００ｍｍに増えるにつれて照度が急激に低下した。これに対し実施例では伸びのある光の照射像が得られた。言い換えれば近傍の被照射面から遠方の被照射面までむらなく光を照射することが出来た。かかる効果は溝の側部の平均斜度が２０度以下であること、又は頂角Ｖが１４０度以上であることに依拠すると考えられる。 As shown in FIG. 23, in Comparative Examples 3 and 8, the illuminance rapidly decreased as the distance increased from 500 mm to 1000 mm. On the other hand, in the example, an elongated light irradiation image was obtained. In other words, it was possible to irradiate light uniformly from a nearby irradiated surface to a distant irradiated surface. Such an effect is considered to be based on the fact that the average slope of the side portion of the groove is 20 degrees or less, or the apex angle V is 140 degrees or more.
　図２３に示すように比較例８及び２では鋭く立ち上がる極大点が見られた。これに対し実施例では目立つ極大点が見られなかった。言い換えれば光の照射像中に目立った輝線は見られなかった。かかる効果は反射シートが内部反射面側に設けられていることに依拠すると考えられる。 As shown in FIG. 23, in Comparative Examples 8 and 2, a maximal point rising sharply was observed. On the other hand, the conspicuous maximum point was not seen in the Example. In other words, no conspicuous bright lines were seen in the light irradiation image. Such an effect is considered to depend on the fact that the reflection sheet is provided on the internal reflection surface side.
　図２４に示すようにＸ軸方向の照度分布には特段の差が見られなかった。 As shown in FIG. 24, no particular difference was observed in the illuminance distribution in the X-axis direction.
　図２５及び２６を用いて断面における溝の輪郭線を台形とした場合に溝の側部の平均斜度が照度に与える影響を説明する。図２５及び２６には実施例５－７及び比較例９の照度分布を表すグラフが示されている。図２５は＋Ｙ方向である。図２６は－Ｘ方向である。 25 and 26, the influence of the average inclination of the side portion of the groove on the illuminance when the contour line of the groove in the cross section is a trapezoid will be described. 25 and 26 are graphs showing the illuminance distributions of Example 5-7 and Comparative Example 9. FIG. FIG. 25 is the + Y direction. FIG. 26 is the −X direction.
　各実施例及び比較例では以下の点が実施例１と異なる。いずれの実施例及び比較例も断面における溝の輪郭線は台形である。図３に示す上底Ｂｕの幅は２．５μｍである。側部の平均斜度及び頂角Ｖはそれぞれ、実施例５（１２．５度、Ｖ１５５）、実施例６（１５度、Ｖ１５０）、実施例７（１７．５度、Ｖ１４５）、及び比較例９（２５度、Ｖ１３０）と表される。 The following points are different from Example 1 in each Example and Comparative Example. In both examples and comparative examples, the contour line of the groove in the cross section is a trapezoid. The width of the upper base Bu shown in FIG. 3 is 2.5 μm. The average slope and apex angle V of the side portions are Example 5 (12.5 degrees, V155), Example 6 (15 degrees, V150), Example 7 (17.5 degrees, V145), and Comparative Example, respectively. 9 (25 degrees, V130).
　図２５に示すように比較例９では距離が５００ｍｍから１０００ｍｍに増えるにつれて照度が急激に低下した。これに対し実施例では伸びのある光の照射像が得られた。言い換えれば近傍の被照射面から遠方の被照射面までむらなく光を照射することが出来た。かかる効果は溝の側部の平均斜度が２０度以下であること、又は頂角Ｖが１４０度以上であることに依拠すると考えられる。かかるまた効果は溝が三角形であっても台形であっても得られることが分かった。 As shown in FIG. 25, in Comparative Example 9, the illuminance rapidly decreased as the distance increased from 500 mm to 1000 mm. On the other hand, in the example, an elongated light irradiation image was obtained. In other words, it was possible to irradiate light uniformly from a nearby irradiated surface to a distant irradiated surface. Such an effect is considered to be based on the fact that the average slope of the side portion of the groove is 20 degrees or less, or the apex angle V is 140 degrees or more. It has been found that such an effect can be obtained regardless of whether the groove is triangular or trapezoidal.
　図２６に示すようにＸ軸方向の照度分布には特段の差が見られなかった。 As shown in FIG. 26, no particular difference was observed in the illuminance distribution in the X-axis direction.
　図２７及び２８を用いて断面における溝の側部が湾曲した場合の影響を説明する。溝の側部の湾曲については図３に示す側部Ｌａ３及び４と上述の説明を参照のこと。図２７及び２８には実施例８、９及び１並びに比較例１０の照度分布を表すグラフが示されている。図２７は＋Ｙ方向である。図２８は－Ｘ方向である。 27 and 28, the influence when the side portion of the groove in the cross section is curved will be described. See the side portions La3 and 4 shown in FIG. 3 and the above description for the curvature of the sides of the groove. 27 and 28 show graphs showing the illuminance distributions of Examples 8, 9, and 1 and Comparative Example 10. FIG. FIG. 27 shows the + Y direction. FIG. 28 is the −X direction.
　各実施例及び比較例では以下の点が実施例１と異なる。いずれの実施例及び比較例も断面における溝の側部は湾曲している。実施例１では、断面における溝の側部は直線状である。溝の中での深さに関わらず頂角Ｖは１５０度で一定である。側部の傾斜は１５度で一定である。 The following points are different from Example 1 in each Example and Comparative Example. In any of the examples and comparative examples, the side portion of the groove in the cross section is curved. In Example 1, the side part of the groove in the cross section is linear. Regardless of the depth in the groove, the apex angle V is constant at 150 degrees. The side slope is constant at 15 degrees.
　実施例８では、断面における頂角Ｖは溝の最も深いところで１５０度である。頂角Ｖは溝の最も浅いところ、すなわち溝の縁で１４０度である。溝の側部の接線の傾斜は溝の中での深さが大きくなるにつれて２０度から１５度まで滑らかに変化する。 In Example 8, the apex angle V in the cross section is 150 degrees at the deepest part of the groove. The apex angle V is 140 degrees at the shallowest part of the groove, that is, at the edge of the groove. The slope of the tangent on the side of the groove changes smoothly from 20 degrees to 15 degrees as the depth in the groove increases.
　実施例９では、断面における頂角Ｖは溝の最も深いところで１５５度である。頂角Ｖは溝の最も浅いところ、すなわち溝の縁で１４０度である。溝の側部の接線の傾斜は溝の中での深さが大きくなるにつれて２０度から１２．５度まで滑らかに変化する。 In Example 9, the apex angle V in the cross section is 155 degrees at the deepest part of the groove. The apex angle V is 140 degrees at the shallowest part of the groove, that is, at the edge of the groove. The slope of the tangent to the side of the groove changes smoothly from 20 degrees to 12.5 degrees as the depth in the groove increases.
　比較例１０の溝は実施例１と異なり台形を基本形とする溝である。さらに比較例１０では、断面における頂角Ｖは溝の最も深いところで１２０度である。頂角Ｖは溝の最も浅いところ、すなわち溝の縁で６０度である。溝の側部の接線の傾斜は溝の中での深さが大きくなるにつれて６０度から３０度まで滑らかに変化する。 Unlike Example 1, the groove of Comparative Example 10 is a groove having a trapezoidal basic shape. Furthermore, in Comparative Example 10, the apex angle V in the cross section is 120 degrees at the deepest portion of the groove. The apex angle V is 60 degrees at the shallowest part of the groove, that is, at the edge of the groove. The slope of the tangent on the side of the groove changes smoothly from 60 degrees to 30 degrees as the depth in the groove increases.
　図２７に示すように比較例１０では距離が５００－６００ｍｍの付近に照度の極小点が見られた。これに対し実施例ではこのような目立った照度の極小点は見られなかった。すなわち実施例では近傍の被照射面を明るく照らしつつ、遠方の被照射面まで滑らかに照度分布を変化させることができた。かかる効果は溝の側部の平均斜度が２０度以下であること、又は頂角Ｖが１４０度以上であることに依拠すると考えられる。 As shown in FIG. 27, in Comparative Example 10, a minimum point of illuminance was observed in the vicinity of the distance of 500 to 600 mm. On the other hand, in the example, such a remarkable minimum point of illuminance was not seen. In other words, in the example, the illuminance distribution could be smoothly changed to a distant irradiated surface while brightly illuminating a nearby irradiated surface. Such an effect is considered to be based on the fact that the average slope of the side portion of the groove is 20 degrees or less, or the apex angle V is 140 degrees or more.
　図２８に示すようにＸ軸方向の照度分布には特段の差が見られなかった。 As shown in FIG. 28, no particular difference was observed in the illuminance distribution in the X-axis direction.
　図２９及び３０を用いて凸条の断面の形状の影響を説明する。図２９及び３０には実施例１及び１０－１３並びに比較例７及び１１の照度分布を表すグラフが示されている。図２９は＋Ｙ方向である。図３０は－Ｘ方向である。 The influence of the cross-sectional shape of the ridge will be described with reference to FIGS. 29 and 30 are graphs showing the illuminance distributions of Examples 1 and 10-13 and Comparative Examples 7 and 11. FIG. FIG. 29 shows the + Y direction. FIG. 30 shows the −X direction.
　実施例１の凸条は上述の通り、アスペクト比２０％のレンチキュラーである。凸条の断面における凸条の輪郭線の法線が基準平面に対して成す角度は、凸条の中での高さに応じて、凸条の基部における５３．１度から、凸条の頂点における０度まで変化する。各実施例では以下の点が実施例１と異なる。 As described above, the ridge of Example 1 is a lenticular with an aspect ratio of 20%. The angle formed by the normal of the contour line of the ridge in the section of the ridge with respect to the reference plane is 53.1 degrees at the base of the ridge, depending on the height in the ridge, and the vertex of the ridge. Vary to 0 degrees. Each embodiment differs from the first embodiment in the following points.
　実施例１０では、凸条の断面の輪郭線の形状を放射線（Parabora）とした。放物線は、以下の数式で表される。 In Example 10, the shape of the outline of the cross-section of the ridges was radiation (Parabora). The parabola is expressed by the following mathematical formula.
　　　Ｖ＝Ｖｔｏｐ－ｋＵ２　　（式－放物線） V = V top −kU 2 (formula−parabola)
　　　ＶｔｏｐはＵ＝０における凸条の高さを表す。 V top represents the height of the ridge at U = 0.
　本実施例ではｋ＝０．４である。 In this example, k = 0.4.
　以下に数式の内容を記載する。図３１に示すように内部反射面４２を構成している凸条５１をＸ－Ｚ平面で切断した時の輪郭線を凸条５１の断面形状とする。図中には１本の代表となる凸条として凸条５１が示されている。当該断面形状において、Ｘ－Ｚ平面と凸条５１の底面の交線を交線５３とする。なお凸条５１の底面は導光板内部にあるため実際には輪郭線として現れていないことに留意する。交線５３の線分長さの１／２を単位長さ（＝１）とする。交線５３の中心を新たにＵＶ座標系の原点とする。Ｘ軸と平行な軸をＵ軸とする。Ｚ軸と平行な軸をＶ軸とする。 The following is the contents of the formula. As shown in FIG. 31, the contour line when the ridge 51 constituting the internal reflection surface 42 is cut along the XZ plane is defined as the cross-sectional shape of the ridge 51. In the drawing, a ridge 51 is shown as one representative ridge. In the cross-sectional shape, an intersection line between the XZ plane and the bottom surface of the protrusion 51 is defined as an intersection line 53. It should be noted that the bottom surface of the ridge 51 does not actually appear as a contour line because it is inside the light guide plate. ½ of the length of the line segment of the intersection line 53 is set as a unit length (= 1). The center of the intersection line 53 is newly set as the origin of the UV coordinate system. The axis parallel to the X axis is taken as the U axis. An axis parallel to the Z axis is taken as a V axis.
　このとき、放物線は、Ｖ＝Ｖｔｏｐ－ｋＵ２　　（式－放物線）で表される。ここでＶｔｏｐはＵ＝０における凸条の高さを表す。図３１に示す凸条５１の断面における凸条の輪郭線の接線が基準平面Ｐｓに対して成す角度は、凸条の中での高さに応じて、凸条の基部におけるＴａ１＝３８．７度から、凸条の頂点におけるＴａ２＝０度まで変化する。 At this time, the parabola is expressed by V = V top −kU 2 (formula−parabola). Here, V top represents the height of the ridge at U = 0. The angle formed by the tangent line of the outline of the ridge in the cross section of the ridge 51 shown in FIG. 31 with respect to the reference plane Ps is Ta1 = 38.7 at the base of the ridge according to the height in the ridge. It changes from degree to Ta2 = 0 degree at the top of the ridge.
　実施例１１では、凸条を楕円形（Ellipse）の断面を有するレンチキュラーレンズとした。すなわち凸条の断面の輪郭線の形状を楕円弧とした。図３１に表されるＵＶ座標系を援用して楕円弧の元となる楕円を説明する。楕円は以下の数式で表される。 In Example 11, the ridge was a lenticular lens having an elliptical cross section. That is, the shape of the outline of the cross section of the ridge was an elliptical arc. The ellipse that is the origin of the elliptical arc will be described with the help of the UV coordinate system shown in FIG. The ellipse is represented by the following formula.
Figure JPOXMLDOC01-appb-M000001
 　　　　　　　　　　　　　　　　（式－楕円）
Figure JPOXMLDOC01-appb-M000001
 (Formula-ellipse)
　Ｐ＝１．２、Ｑ＝１．２とした。図３１に示す凸条５１の断面における凸条５１の輪郭線の法線が基準平面Ｐｓに対して成す角度は、凸条５１の中での高さに応じて、凸条の基部におけるＴａ１＝５４．４度から、凸条５１の頂点におけるＴａ２＝０度まで変化する。 P = 1.2 and Q = 1.2. The angle formed by the normal line of the contour line of the ridge 51 in the cross section of the ridge 51 shown in FIG. 31 with respect to the reference plane Ps is Ta1 = at the base of the ridge, depending on the height in the ridge 51. It changes from 54.4 degrees to Ta2 = 0 degree at the top of the ridge 51.
　実施例１２では、凸条の断面の輪郭線の形状を上述の（式－放物線）に従って導き出した放射線（Parabora）とした。ｋ＝１．０とした。図３１に示す凸条５１の断面における凸条５１の輪郭線の法線が基準平面Ｐｓに対して成す角度は、凸条５１の中での高さに応じて、凸条５１の基部におけるＴａ１＝６３．４度から、凸条５１の頂点におけるＴａ２＝０度まで変化する。 In Example 12, the shape of the contour line of the cross section of the ridge was the radiation (Parabora) derived according to the above (formula-parabola). k = 1.0. The angle formed by the normal line of the contour line of the ridge 51 in the cross section of the ridge 51 shown in FIG. 31 with respect to the reference plane Ps depends on the height of the ridge 51 and Ta1 at the base of the ridge 51. It changes from 63.4 degrees to Ta2 = 0 degree at the top of the ridge 51.
　実施例１３では、実施例１と同じく、凸条の断面の輪郭線をレンチキュラー（Lenticular）とした。ただし、アスペクト比を３５％とした。凸条の断面における凸条の輪郭線の法線が基準平面に対して成す角度は、凸条の中での高さに応じて、凸条の基部における７２．５度から、凸条の頂点における０度まで変化する。 In Example 13, as in Example 1, the contour line of the cross section of the ridge was lenticular. However, the aspect ratio was set to 35%. The angle formed by the normal of the contour line of the ridge in the section of the ridge with respect to the reference plane is 72.5 degrees at the base of the ridge, depending on the height in the ridge, and the vertex of the ridge. Vary to 0 degrees.
　比較例１１では、凸条の断面の輪郭線の形状を凸条の基部の側が広い等脚台形（Trapezoid）とした。脚と下底の間の角度は５５度とした。 In Comparative Example 11, the shape of the contour line of the cross section of the ridge was a trapezoid having a wide base on the ridge base side. The angle between the leg and the lower base was 55 degrees.
　比較例７においては内部反射面に凸条を設けなかった。先に述べたとおりである。 In Comparative Example 7, no protrusion was provided on the internal reflection surface. As described above.
　図２９に示すように各実施例と比較例１１との比較より、凸条の断面における凸条の輪郭線は滑らかに湾曲する円弧、楕円弧、又は放物線からなることが好ましいことが分かった。比較例１１のように凸条の断面形状が台形状である場合、基準点からの距離が１０００ｍｍの付近に照度の極小点が見られるため好ましい照度分布とは言えない。 As shown in FIG. 29, it was found from the comparison between each Example and Comparative Example 11 that the contour line of the ridge in the section of the ridge is preferably a smoothly curved arc, elliptical arc, or parabola. When the cross-sectional shape of the ridges is trapezoidal as in Comparative Example 11, a minimum illuminance point is seen in the vicinity of a distance of 1000 mm from the reference point, which is not a preferable illuminance distribution.
　これに対し、実施例１２と１３では凸条の基部における凸条の輪郭線の接線が、基準平面に対して成す角が６０度以上である。これらの実施例では、基準点からの距離が５００ｍｍの付近が照度最大となる。このため、基準点近辺の照度が低下するもの、低下の度合いは比較例２及び８よりも穏やかであった。 On the other hand, in Examples 12 and 13, the angle formed by the tangent of the contour line of the ridge at the base of the ridge with respect to the reference plane is 60 degrees or more. In these embodiments, the illuminance is maximum when the distance from the reference point is 500 mm. For this reason, the illuminance near the reference point decreased, and the degree of decrease was milder than those of Comparative Examples 2 and 8.
　また実施例１、１０、１１では凸条の基部における凸条の輪郭線の接線が、基準平面に対して成す角が６０度以下である。これらの実施例では基準点近辺が照度最大となり、また滑らかに照度が変化するのでより好ましいことが分かった。凸条が上記の通りの形状を有することは、伸びのある光の照射像を得るのに適することが分かった。 Also, in Examples 1, 10, and 11, the angle formed by the tangent line of the contour line of the ridge at the base of the ridge with respect to the reference plane is 60 degrees or less. In these examples, it was found that the vicinity of the reference point has the maximum illuminance, and the illuminance changes smoothly, which is more preferable. It has been found that having the shape of the ridges as described above is suitable for obtaining a stretched light irradiation image.
　図３０に示すようにＸ軸方向の照度分布には特段の差が見られなかった。 As shown in FIG. 30, no particular difference was observed in the illuminance distribution in the X-axis direction.
　図３２及び図３３を用いて内部反射面を覆う反射シートの反射面の拡散反射率の影響を説明する。図３２及び図３３には実施例１及び実施例１４の照度分布を表すグラフが示されている。図３２は＋Ｙ方向である。図３３は－Ｘ方向である。 32 and 33, the influence of the diffuse reflectance of the reflection surface of the reflection sheet covering the internal reflection surface will be described. 32 and 33 show graphs representing the illuminance distributions of Examples 1 and 14. FIG. FIG. 32 shows the + Y direction. FIG. 33 shows the −X direction.
　実施例１の反射シートは先に述べたとおり拡散タイプである（Diffuser type）。その反射面は９０％以上の拡散反射率を有する。かかる反射面が導光板の内部反射面を覆っている。 The reflection sheet of Example 1 is a diffusion type (Diffuser type) as described above. The reflecting surface has a diffuse reflectance of 90% or more. Such a reflective surface covers the internal reflective surface of the light guide plate.
　これに対して実施例１４の反射シートは鏡面タイプである。その反射面は鏡面である。かかる反射面が導光板の内部反射面を覆っている。 On the other hand, the reflective sheet of Example 14 is a mirror surface type. The reflecting surface is a mirror surface. Such a reflective surface covers the internal reflective surface of the light guide plate.
　図３２に示すように各実施例の比較より、内部反射面を覆う反射シートにおいて、その反射面の拡散反射率は９０％以上であることが好ましいことが分かった。反射シートの反射面が上記の通り制限されることは、特に面状発光モジュールの直下の照度を高めるのに適することが分かった。また、このように反射シートの拡散反射率が照度分布に影響することは、図９に示すように内部反射面４２から出射する光が多いことと符合する。 As shown in FIG. 32, it was found from the comparison of each example that in the reflective sheet covering the internal reflective surface, the diffuse reflectance of the reflective surface is preferably 90% or more. It has been found that limiting the reflection surface of the reflection sheet as described above is particularly suitable for increasing the illuminance immediately below the planar light emitting module. Further, the fact that the diffuse reflectance of the reflection sheet influences the illuminance distribution in this way coincides with a large amount of light emitted from the internal reflection surface 42 as shown in FIG.
　図３３に示すようにＸ軸方向の照度分布にも影響が見られた。 As shown in FIG. 33, the illuminance distribution in the X-axis direction was also affected.
　図３４及び図３５を用いて偏向面上の溝の蛇行のα値の影響を説明する。図３４には実施例１及び１５並びに比較例１２－１３の照度分布を表すグラフが示されている。図３５には実施例２及び１６－１７並びに比較例１４－１５の照度分布を表すグラフが示されている。図３４及び図３５はいずれも＋Ｙ方向の照度分布を表している。 34 and 35, the influence of the α value of the meandering groove on the deflection surface will be described. FIG. 34 shows a graph representing the illuminance distribution of Examples 1 and 15 and Comparative Examples 12-13. FIG. 35 is a graph showing the illuminance distribution of Examples 2 and 16-17 and Comparative Example 14-15. 34 and 35 both show the illuminance distribution in the + Y direction.
　実施例１及び２の偏向面上の溝の蛇行は先に述べたとおりである。すなわち溝のベースラインの蛇行の単位長Ｕｌは０．５ｍｍである。溝のベースラインの蛇行の振幅は７０μｍ（０．０７ｍｍ）である。α値は０．１４である。これに対して他の実施例及び比較例の単位長Ｕｌは実施例１及び２と同じ０．５ｍｍとする。 The meandering of the grooves on the deflection surfaces of Examples 1 and 2 is as described above. That is, the unit length Ul of the meandering of the base line of the groove is 0.5 mm. The amplitude of the meandering of the groove baseline is 70 μm (0.07 mm). The α value is 0.14. On the other hand, the unit length Ul of the other examples and comparative examples is set to 0.5 mm, which is the same as those of Examples 1 and 2.
　比較例１２及び１４の蛇行の振幅は３０μｍ（０．０３ｍｍ）である。α値は０．０６である。比較例１３及び１５の蛇行の振幅は５０μｍ（０．０５ｍｍ）である。α値は０．１０である。実施例１６の蛇行の振幅は６０μｍ（０．０６ｍｍ）である。α値は０．１２である。実施例１５及び１７の蛇行の振幅は１００μｍ（０．１０ｍｍ）である。α値は０．２０である。 The meandering amplitude of Comparative Examples 12 and 14 is 30 μm (0.03 mm). The α value is 0.06. The meandering amplitude of Comparative Examples 13 and 15 is 50 μm (0.05 mm). The α value is 0.10. The amplitude of meandering in Example 16 is 60 μm (0.06 mm). The α value is 0.12. The amplitude of meandering in Examples 15 and 17 is 100 μm (0.10 mm). The α value is 0.20.
　図３４及び図３５に示す実施例と比較例との比較より、α値を０．１２以上とすることで照度分布を基準点からの距離に応じて滑らかに変化させられることが分かった。 34 and 35, it was found that the illuminance distribution can be smoothly changed according to the distance from the reference point by setting the α value to 0.12 or more from the comparison between the example shown in FIGS.
［第３部］　受光面から遠い側の斜面の働き [Part 3] Work of the slope far from the light receiving surface
　図３に戻る。溝の斜面を表す側部Ｌａ１及び２のうち、受光面から遠い側の側部Ｌａ２の働きについて説明する。以下に説明する実施例１８では、側部Ｌａ１の斜度Ｏｂ１を１５度とした。また側部Ｌａ２の斜度Ｏｂ２を４０度とした。このように非対称な溝を用いて偏向面を作製した。 Return to Fig. 3. Of the side portions La1 and La2 representing the slope of the groove, the function of the side portion La2 far from the light receiving surface will be described. In Example 18 described below, the slope Ob1 of the side portion La1 was set to 15 degrees. Further, the slope Ob2 of the side portion La2 was set to 40 degrees. In this way, a deflection surface was produced using an asymmetric groove.
　図３６は実施例１８にかかる導光装置９０の断面の特徴を模式的に表している。導光装置９０は導光板８５を備える。導光板８５は偏向面８１を備える。偏向面８１には溝８７ａ－ｅが設けられている。 FIG. 36 schematically illustrates a cross-sectional feature of the light guide device 90 according to the eighteenth embodiment. The light guide device 90 includes a light guide plate 85. The light guide plate 85 includes a deflection surface 81. The deflection surface 81 is provided with grooves 87a-e.
　図３６に示す導光板８５の断面において溝８７ｂの輪郭線は左右非対称な三角形となっている。導光方向Ｇｕから分かるように、受光面に近い側の斜度Ｏｂ１は受光面より遠い側の斜度Ｏｂ２よりも小さい。上述の通りＯｂ１は１５度であり、Ｏｂ２は４０度である。溝の有するその他の特徴は実施例１と同様とする。溝８７ａ及びｃ－ｅも同様である。 In the cross section of the light guide plate 85 shown in FIG. As can be seen from the light guide direction Gu, the slope Ob1 on the side closer to the light receiving surface is smaller than the slope Ob2 on the side farther from the light receiving surface. As described above, Ob1 is 15 degrees and Ob2 is 40 degrees. Other features of the groove are the same as those in the first embodiment. The same applies to the grooves 87a and ce.
　図３７には実施例１８の導光装置を用いて作製した面状発光モジュールの配光分布グラフが示されている。配光曲線８３は実施例１の配光曲線である。配光曲線８４は実施例１８の配光曲線である。－９０度が図１及び１８に示す－Ｙ方向を、９０度が図１及び１８に示す＋Ｙ方向を表している。 FIG. 37 shows a light distribution graph of the planar light emitting module manufactured using the light guide device of Example 18. A light distribution curve 83 is a light distribution curve of the first embodiment. The light distribution curve 84 is the light distribution curve of Example 18. -90 degrees represents the -Y direction shown in FIGS. 1 and 18, and 90 degrees represents the + Y direction shown in FIGS.
　図３６に戻る。光線５７ｃは反射面４９で乱反射し、その一部が溝８７ｃの有する側部Ｌａ１の斜面から出射する。かかる出射の態様は、図５に示したにかかる導光装置４０でもまた実施例１にかかる導光装置でも生じる。したがって図３７に示すように配光曲線８３及び配光曲線８４の間には配光特性に劇的な変化がない。 Return to FIG. The light ray 57c is irregularly reflected by the reflection surface 49, and a part thereof is emitted from the slope of the side portion La1 of the groove 87c. Such a mode of emission occurs both in the light guide device 40 according to FIG. 5 and in the light guide device according to the first embodiment. Therefore, as shown in FIG. 37, there is no dramatic change in the light distribution characteristics between the light distribution curve 83 and the light distribution curve 84.
　図３６に戻る。光線５７ｄは反射面４９で乱反射し、その一部の光線ｅが溝８７ｄ及びｅの間にある平坦面より出射する。したがって、図３７に示す配光曲線８３では配光曲線８４に比べて＋６０度よりも角度が小さい領域で光度が増加している。 Return to FIG. The light ray 57d is irregularly reflected by the reflection surface 49, and a part of the light ray e is emitted from a flat surface between the grooves 87d and e. Therefore, in the light distribution curve 83 shown in FIG. 37, the light intensity increases in a region where the angle is smaller than +60 degrees compared to the light distribution curve 84.
　図３６に戻る。光線５７ｄは反射面４９で乱反射し、その一部の光線５７ｆが溝８７ｅの有する側部Ｌａ１より出射するものの、溝８７ｅの有する側部Ｌａ２に再び入射する。したがって、光線５７ｆは導光方向Ｇｕに沿ってさらに導光板内を伝播していく。言い換えれば光線５７ｆは出射面の法線方向に対して高角度方向に出射する予定であったところ、大きな斜度Ｏｂ２を有する側部Ｌａ２によってこれが阻害されている。このため図３７に示す配光曲線８３では配光曲線８４に比べて＋６０度よりも角度が大きい領域で光度が減少している。 Return to FIG. The light ray 57d is irregularly reflected by the reflecting surface 49, and a part of the light ray 57f is emitted from the side portion La1 of the groove 87e, but is incident again on the side portion La2 of the groove 87e. Therefore, the light beam 57f further propagates in the light guide plate along the light guide direction Gu. In other words, the light beam 57f was supposed to be emitted in a high angle direction with respect to the normal direction of the emission surface, but this is hindered by the side portion La2 having a large inclination Ob2. For this reason, in the light distribution curve 83 shown in FIG. 37, the light intensity decreases in a region where the angle is larger than +60 degrees compared to the light distribution curve 84.
　実施例１８と実施例１の比較より、出射面の法線方向に対して高角度の方向に光が出射することを促進するには、受光面より遠い側の斜面の傾斜を小さくすればよいことが分かる。また受光面より遠い側の斜面の傾斜も、受光面に近い側の斜面の傾斜に合わせて１２．５度～２０度の範囲にあることが好ましい。 From the comparison between Example 18 and Example 1, in order to promote the emission of light in a direction at a high angle with respect to the normal direction of the emission surface, the slope of the slope farther from the light receiving surface may be reduced. I understand that. The slope of the slope farther from the light receiving surface is preferably in the range of 12.5 degrees to 20 degrees in accordance with the slope of the slope closer to the light receiving face.
　実施例１８では、より高角度方向に光を出射する場合には、溝の斜面のうち受光面より遠い側の斜面の傾斜も、１２．５度～２０度の範囲にあることが好ましいことを示した。かかる溝を用いることでさらに他の態様の面状発光モジュールを得ることが出来る。 In Example 18, when light is emitted in a higher angle direction, it is preferable that the slope of the slope farther from the light receiving surface among the slopes of the groove is also in the range of 12.5 degrees to 20 degrees. Indicated. By using such a groove, a planar light emitting module of still another embodiment can be obtained.
　図３８には実施例１９の面状発光モジュール９５の正面図である。面状発光モジュール９５が図６に示す面状発光モジュール７０と異なる点は、反射材６７が撤去されている点と、端面４３ｂに対向している点光源群９６を備える点である。 38 is a front view of the planar light emitting module 95 of Example 19. FIG. The planar light emitting module 95 is different from the planar light emitting module 70 shown in FIG. 6 in that the reflecting material 67 is removed and a point light source group 96 facing the end surface 43b is provided.
　図３８に示す面状発光モジュール９５は点光源群を２個備える。第１の点光源群は点光源群６６である。第２の点光源群は点光源群９６である。導光板４５は入射端面を２面有する。 38 is provided with two point light source groups. The first point light source group is a point light source group 66. The second point light source group is a point light source group 96. The light guide plate 45 has two incident end faces.
　図３８に示す端面４３ａ及びｂのうち、端面４３ａの有する受光面を第１の受光面とする。端面４３ａの有する受光面は点光源群６６と対向する。一方、端面４３ｂの有する受光面を第２の受光面とする。端面４３ｂの有する受光面は点光源群９６と対向する。第１及び第２の受光面は導光板６５の中央部を挟んで対向する。導光板６５の中央部には偏向面４１が設けられている。 38. Of the end surfaces 43a and 43b shown in FIG. 38, the light receiving surface of the end surface 43a is defined as a first light receiving surface. The light receiving surface of the end face 43 a faces the point light source group 66. On the other hand, the light receiving surface of the end face 43b is defined as a second light receiving surface. The light receiving surface of the end face 43 b faces the point light source group 96. The first and second light receiving surfaces face each other with the central portion of the light guide plate 65 interposed therebetween. A deflection surface 41 is provided at the center of the light guide plate 65.
　図３８に示す偏向面４１の備える溝４７ａ及びｂは、端面４３ａの側においても、端面４３ｂの側においても、断面における平均斜度が１２．５度～２０度の範囲にある。したがって偏向面４１は二つの出射方向Ｅｘ１及び３を有する発光面として機能する。 38. The grooves 47a and b provided in the deflection surface 41 shown in FIG. 38 have an average slope in the range of 12.5 degrees to 20 degrees on both the end face 43a side and the end face 43b side. Therefore, the deflection surface 41 functions as a light emitting surface having two emission directions Ex1 and Ex3.
　すなわち図３８に示す点光源群６６の光は、出射方向Ｅｘ１に沿って、端面４３ｂの有する受光面の側に向かって出射する。一方、点光源群９６の光は、出射方向Ｅｘ３に沿って、端面４３ａの有する受光面の側に向かって出射する。 That is, the light from the point light source group 66 shown in FIG. 38 is emitted toward the light receiving surface side of the end face 43b along the emission direction Ex1. On the other hand, the light from the point light source group 96 is emitted toward the light receiving surface side of the end face 43a along the emission direction Ex3.
　なお、本発明は上記実施の形態に限られたものではなく、趣旨を逸脱しない範囲で適宜変更することが可能である。 Note that the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit of the present invention.
　この出願は、２０１７年３月６日に出願された日本出願特願２０１７－０４２０３２を基礎とする優先権を主張し、その開示の全てをここに取り込む。 This application claims priority based on Japanese Patent Application No. 2017-04-2032 filed on March 6, 2017, the entire disclosure of which is incorporated herein.
４０　導光装置、　４１　偏向面、　４２　内部反射面、　４３ａ　端面、　４３ｂ　端面、　４４　断面、　４５　導光板、　４６ａ－ｄ　中心、　４７ａ－ｄ　溝、　４８ａ　谷、　４８ｂ　山、　４９　反射面、　５０　反射シート、　５１　凸条、　５２　円弧、　５５　拡散板、　５７ａ－ｆ　光線、　５８ａ－ｃ　光束、　６０　導光装置、　６１　下底面、　６３　滑面、　６５　導光板、　６６　点光源群、　６７　反射材、　６８　反射シート、　７０　面状発光モジュール、　７１　偏向面、　７５　導光装置、　７７ａ－ｄ　直線状の溝、　８０　被照射面、　８１　偏向面、　８３　配光曲線、　８４　配光曲線、　８５　導光板、　８７ａ－ｅ　溝、　９０　導光装置、　９５　光モジュール、　９６　点光源群、　Ａｎ　角、　Ｂｃ１－２　出射方向、　Ｂｌ　下底、　Ｂｕ　上底、　Ｃｏ　比較例、　Ｄｐ　深さ、　Ｄｘ　配光曲線、　Ｄｙ　配光曲線、　Ｅｘ１－３　出射方向、　Ｇ１－８　領域、　Ｇｕ　導光方向、　Ｉｎ　入射方向、　Ｌａ１－４　側部、　Ｍａ１－２　照度の極大点、　Ｏｂ１－２　斜度、　Ｏｂ２　斜度、　Ｐｓ　基準平面、　Ｒａ　半径、　Ｒｅ　基準点、　Ｕｌ　単位長、　Ｖ　頂角、　Ｖｓ　距離、　Ｗｏ　実施例 40 light guide device, 41 deflection surface, 42 internal reflection surface, 43a end surface, 43b end surface, 44 cross section, 45 light guide plate, 46a-d center, 47a-d groove, 48a valley, 48b mountain, 49b reflection surface, 50 reflection sheet , 51 ridges, 52 arcs, 55 diffusers, 57a-f rays, 58a-c rays, 60 light guides, 61 bottom surfaces, 63 smooth surfaces, 65 light guide plates, 66 point light source groups, 67 reflectors, 68 reflections Sheet, 70 planar light emitting module, 71 deflection surface, 75 light guide device, 77a-d linear groove, 80 illuminated surface, 81 deflection surface, 83 light distribution curve, 84 light distribution curve, 85 light guide plate, 87a- e Groove, 90 light guide device, 95 optical module, 96 point light source group An angle, Bc1-2 emission direction, B1 bottom bottom, Bu top bottom, Co comparison example, Dp depth, Dx light distribution curve, Dy light distribution curve, Ex1-3 emission direction, G1-8 area, Gu light guide direction , In incident direction, La1-4 side, Ma1-2 illuminance maximum point, Ob1-2 slope, Ob2 slope, Ps reference plane, Ra radius, Re reference point, Ul unit length, V apex angle, Vs distance , Wo Examples

Claims (11)

  1. 　導光板と反射シートとを備える導光装置であって、
    　前記導光板は、受光面を有する入射端面と、偏向面を有する下底面と、内部反射面を有する上底面とを有し、
    　前記反射シートは前記内部反射面に対向し、
    　前記偏向面は互いに並行するとともに深さに応じて狭くなる複数の溝を有し、
    　前記溝は前記受光面の近傍から前記受光面の遠方に向かって順に配置されるとともに（以下、この方向を導光方向という。）、前記導光板を平面視した時、滑らかに蛇行しており、
    　前記上底面はさらに、前記内部反射面に設けられた凸条であって、互いに並行するとともに、前記導光方向に沿う向きに延びる凸条を有し、
    　前記受光面の法線と、前記導光板が拡がる基準平面の法線とに平行である断面において、前記基準平面に対する前記溝の輪郭線の側部の平均斜度は前記受光面の側において１２．５度～２０度であり、
    　前記偏向面は前記受光面から遠い側に対して光を出射する発光面として機能する、
    　導光装置。     A light guide device comprising a light guide plate and a reflective sheet,
    The light guide plate has an incident end surface having a light receiving surface, a lower bottom surface having a deflection surface, and an upper bottom surface having an internal reflection surface,
    The reflective sheet faces the internal reflective surface,
    The deflection surface has a plurality of grooves parallel to each other and narrowing according to the depth,
    The grooves are arranged in order from the vicinity of the light receiving surface toward the far side of the light receiving surface (hereinafter, this direction is referred to as a light guide direction), and smoothly meander when the light guide plate is viewed in plan view. ,
    The upper bottom surface is a ridge provided on the internal reflection surface, and has a ridge that is parallel to each other and extends in a direction along the light guide direction,
    In a cross section parallel to the normal line of the light receiving surface and the normal line of the reference plane in which the light guide plate extends, the average slope of the side of the contour line of the groove with respect to the reference plane is 12 on the light receiving surface side. .5 degrees to 20 degrees,
    The deflection surface functions as a light emitting surface that emits light to a side far from the light receiving surface.
    Light guide device.
  2. 　光源から前記導光板の有する入射端面に対して光が入射する場合に、
    　前記入射した光の一部は前記溝にて反射することで拡散し、さらに前記内部反射面にて反射するとともに前記凸条にて拡散し、さらに前記偏向面から出射し、
    　また、前記入射した光の他の一部は、前記内部反射面で反射することなく出射し、さらに前記反射シートで反射することで前記内部反射面より前記導光板内に再進入し、さらに前記偏向面から出射する、
    　ことにより前記偏向面は前記発光面として機能する、
    　請求項１に記載の導光装置。     When light is incident on the incident end face of the light guide plate from the light source,
    A part of the incident light is diffused by being reflected by the groove, is further reflected by the internal reflection surface and is diffused by the ridge, and is further emitted from the deflection surface,
    Further, the other part of the incident light exits without being reflected by the internal reflection surface, and further re-enters the light guide plate from the internal reflection surface by being reflected by the reflection sheet. Emanating from the deflection surface,
    Thus, the deflection surface functions as the light emitting surface.
    The light guide device according to claim 1.
  3. 　前記溝の輪郭線の側部の平均斜度は１３．５度～１７．５度である、
    　請求項１又は２に記載の導光装置。     The average slope of the side of the groove contour line is 13.5 degrees to 17.5 degrees,
    The light guide device according to claim 1 or 2.
  4. 　前記溝の輪郭線は左右対称な台形又は三角形であり、
    　前記溝の輪郭線が台形であれば前記輪郭線の最深部の幅は１～２５０μｍであり、
    　前記溝の深さは２～１００μｍである、
    　請求項１～３のいずれかに記載の導光装置。     The outline of the groove is a symmetrical trapezoid or triangle,
    If the contour line of the groove is trapezoidal, the width of the deepest part of the contour line is 1 to 250 μm,
    The depth of the groove is 2 to 100 μm.
    The light guide device according to any one of claims 1 to 3.
  5. 　前記溝の輪郭線の接線が前記基準平面に対して成す傾斜角は、前記溝の中での深さが大きくなるにつれて単調に小さくなるとともに、前記溝の中での深さに応じて滑らかに変化する、
    　請求項４に記載の導光装置。     The inclination angle formed by the tangent line of the contour line of the groove with respect to the reference plane monotonously decreases as the depth in the groove increases, and smoothly according to the depth in the groove. Change,
    The light guide device according to claim 4.
  6. 　前記複数の溝の間で前記溝の蛇行の位相は互いに一致しており、
    　前記溝の蛇行の谷に対して、前記溝の蛇行の振幅の中心を超えて、隣接する他の前記溝の蛇行の山が入り込む、
    　請求項１～５のいずれかに記載の導光装置。     The meandering phases of the grooves coincide with each other between the plurality of grooves,
    With respect to the meandering valley of the groove, beyond the center of the amplitude of the meandering of the groove, the meandering mountain of another adjacent groove enters.
    The light guide device according to any one of claims 1 to 5.
  7. 　前記凸条の断面における前記凸条の輪郭線は滑らかに湾曲する円弧、楕円弧、又は放物線からなり、
    　前記凸条の輪郭線が、前記凸条の基部において、前記基準平面に対して成す角が６０度以下である、
    　請求項１～６のいずれかに記載の導光装置。     The outline of the ridge in the section of the ridge consists of a smoothly curved arc, an elliptical arc, or a parabola,
    In the base of the ridge, the angle formed by the contour line of the ridge with respect to the reference plane is 60 degrees or less.
    The light guide device according to any one of claims 1 to 6.
  8. 　前記偏向面は前記下底面の中央に位置し、
    　前記下底面は前記偏向面を取り囲む滑面を有する、
    　請求項１～７のいずれかに記載の導光装置。     The deflection surface is located in the center of the lower bottom surface;
    The lower bottom surface has a smooth surface surrounding the deflection surface;
    The light guide device according to any one of claims 1 to 7.
  9. 　請求項１～８のいずれかに記載の導光装置と、点光源群とを備える面状発光モジュールであって
    　前記受光面は点光源群と対向し、
    　前記点光源群は前記偏向面と平行な方向に所定の間隔で列をなす複数の点光源を有する、
    　面状発光モジュール。     A planar light emitting module comprising the light guide device according to any one of claims 1 to 8 and a point light source group, wherein the light receiving surface faces the point light source group,
    The point light source group includes a plurality of point light sources arranged in rows at predetermined intervals in a direction parallel to the deflection surface.
    Planar light emitting module.
  10. 　前記点光源群を２個備え、ここで各点光源群を第１及び第２の点光源群と称し、
    　前記導光板は前記入射端面を２面有し、ここで各入射端面は、前記受光面として、前記偏向面を挟んで互いに対向する第１及び第２の受光面をそれぞれ有し、
    　前記第１及び第２の受光面はそれぞれ前記第１及び第２の点光源群と対向する、
    　ことにより前記偏向面は、前記第１の点光源群の光を前記第２の受光面の側に対して出射するとともに、前記第２の点光源群の光を前記第１の受光面の側に対して出射する発光面として機能する、
    　請求項９に記載の面状発光モジュール。     Two point light source groups are provided, where each point light source group is referred to as a first and second point light source group,
    The light guide plate has two incident end surfaces, and each incident end surface has first and second light receiving surfaces facing each other across the deflection surface as the light receiving surfaces, respectively.
    The first and second light-receiving surfaces are opposed to the first and second point light source groups, respectively.
    Accordingly, the deflecting surface emits the light of the first point light source group toward the second light receiving surface side, and emits the light of the second point light source group to the first light receiving surface side. Function as a light emitting surface that emits
    The planar light emitting module according to claim 9.
  11. 　前記導光板の前記下底面と対向するとともに、前記偏向面から出射する光を散乱する拡散板、又は
    　前記導光板の前記下底面と対向するとともに、前記偏向面から出射する光を透過する透明な保護板をさらに有する、
    　請求項９又は１０に記載の面状発光モジュール。     A diffusing plate that faces the lower bottom surface of the light guide plate and scatters light emitted from the deflection surface, or a transparent plate that faces the lower bottom surface of the light guide plate and transmits light emitted from the deflection surface. Further having a protective plate,
    The planar light emitting module according to claim 9 or 10.
PCT/JP2018/008532 2017-03-06 2018-03-06 Light guide device WO2018164108A1 (en)

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Cited By (1)

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JP2022071790A (en) * 2020-10-28 2022-05-16 アイリスオーヤマ株式会社 Vacuum cleaner

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JP2005500651A (en) * 2001-08-15 2005-01-06 スリーエム イノベイティブ プロパティズ カンパニー Light guide plate used with backlit display
JP2008218418A (en) * 2008-03-31 2008-09-18 Mitsubishi Rayon Co Ltd Surface light source and light guide used for same
JP2011040369A (en) * 2009-06-01 2011-02-24 Skc Haas Display Films Co Ltd Light guide plate for direction-turning film system
JP2015115253A (en) * 2013-12-13 2015-06-22 王子ホールディングス株式会社 Light guide plate

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005500651A (en) * 2001-08-15 2005-01-06 スリーエム イノベイティブ プロパティズ カンパニー Light guide plate used with backlit display
JP2008218418A (en) * 2008-03-31 2008-09-18 Mitsubishi Rayon Co Ltd Surface light source and light guide used for same
JP2011040369A (en) * 2009-06-01 2011-02-24 Skc Haas Display Films Co Ltd Light guide plate for direction-turning film system
JP2015115253A (en) * 2013-12-13 2015-06-22 王子ホールディングス株式会社 Light guide plate

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2022071790A (en) * 2020-10-28 2022-05-16 アイリスオーヤマ株式会社 Vacuum cleaner
JP7145527B2 (en) 2020-10-28 2022-10-03 アイリスオーヤマ株式会社 vacuum cleaner

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