CN104007578B - Planar illuminating device - Google Patents

Abstract

The present invention provides a kind of slim and that light characteristic is excellent planar illuminating device.In planar illuminating device (10), light guide plate (20) have include inclined plane (25) and be arranged to along with from incidence surface (21) side tend to outgoing plane (22) side and wall thickness thinning enter wedge portion (31).This inclined plane (25) has the first inclination face (25a), the second inclination face (25b), the 3rd inclination face (25c) from incidence surface (21) side, second tilts the average slope angle (θ 2) of face (25b) tilts the average slope angle (θ 1, θ 3) of face (25c) more than the first inclination face (25a) and the 3rd, it is possible to reduce the light leak near wedge portion (31) that enters from inclined plane (25) and outgoing plane (22), improve the light characteristic of illumination light.

Description

Planar illuminating device

Technical field

The present invention relates to possess and configure light source in light inputting end face and from the illumination light of injection part injection planar The planar illuminating device of the lateral emitting mode of light guide plate.

Background technology

As the lighting unit of display panels, with the neck of the miniature portable information equipments such as mobile phone Centered by territory, widely used configure small-sized and environmental suitability is excellent by the side end face along light guide plate LED and the planar illuminating device (backlight) of lateral emitting mode that formed.All the time, in order to Tackle the most lightening of miniature portable information equipment, use shape between incidence surface and injection part Become to have along with the side end face (hereinafter referred to as incidence surface) being configured away from LED that thickness gradually becomes The thin light guide plate entering wedge portion.By using such light guide plate, regardless of the thickness of LED Can the injection part (for example, referring to patent documentation 1 and 2) of thinning light guide plate.

[patent documentation 1] Japanese Unexamined Patent Publication 2007-287550 publication

[patent documentation 2] Japanese Unexamined Patent Publication 2008-170739 publication

But, the lightening requirement for liquid crystal indicator is the harshest, for as liquid crystal The planar illuminating device that the backlight of showing device uses, is also strongly required the most lightening.Such as, As to the thickness of the LED used and enter what the length on light conducting direction in wedge portion gave Condition, in order to make injection part lightening, needs to increase the inclination angle constituting the inclined plane into wedge portion. But, if increasing the inclination angle of inclined plane, then enter wedge portion from enter wedge portion and injection part Neighbouring light leak increases, thus produces the brightness of the injection light from injection part utilized as illumination light The problem that the Luminance Distribution of reduction and illumination light deteriorates.

Summary of the invention

The present invention completes in view of above-mentioned problem just, its object is to provide one will not produce bright The reduction of degree and the deterioration etc. of Luminance Distribution, the lightening planar illuminating device of injection part can be made.

The structure of the present invention is only illustrated by invention below mode, for easy to understand The diversified structure of invention, itemizes at this and illustrates.Every being not intended to limits the present invention's Technical scope, wants with reference to replacing, delete every composition for the detailed description of the invention that carries out an invention A part for element or the mode of other element the most additional, be also included in the present application Technical scope.

(1) a kind of planar illuminating device, possesses light source and light guide plate, and this light guide plate has for this light The incidence surface of source configuration and make the outgoing plane from the incident light injection of this incidence surface, above-mentioned planar light Device is characterised by, above-mentioned light guide plate has into wedge portion, and this enters wedge portion and includes inclined plane, and Be arranged to along with from above-mentioned incidence surface side tend to above-mentioned outgoing plane side and wall thickness is thinning, above-mentioned inclined plane from Above-mentioned incidence surface side is risen has the first inclination face, the second inclination face and the 3rd inclination face, on State the second inclination face, optional position on the long side direction that is located at above-mentioned incidence surface with above-mentioned enter Average slope angle in bright finish and the orthogonal cross section of above-mentioned outgoing plane is more than in same above-mentioned cross section Above-mentioned first tilts the facial and above-mentioned 3rd average slope angle tilting face.(technical scheme 1).

The present inventor conducts in-depth research to solve above-mentioned problem, found that: in recent years The light guide plate tending to lightening and narrow frame enter in wedge portion, near the region of its incidence surface Dangerous high with produce light leak compared with the region of central authorities near the region of outgoing plane.The present invention is just Complete in view of above-mentioned discovery.

And then, according to the planar illuminating device that this is described, with along with tending to above-mentioned from incidence surface side The inclined plane entering wedge portion that outgoing plane side and the thinning mode of wall thickness are arranged has from incidence surface side First tilts face, the second inclination face, the 3rd inclination face, and second tilts the facial (district of central authorities Territory), optional position on the long side direction that is located at incidence surface orthogonal with incidence surface and outgoing plane Cross section in average slope angle more than the first inclination face (district near incidence surface in same cross section Territory) and the average slope angle of the 3rd inclination face (near the region of outgoing plane), thereby, it is possible to It is effectively reduced from the relatively high close incidence surface of danger producing light leak entered in wedge portion Region and the light leak in region near outgoing plane, and can reduce from outgoing plane near entering wedge The light of the region injection in portion.

(2) planar illuminating device is characterised by, at the planar illuminating device described in (1) item On the basis of, above-mentioned first tilts the facial and above-mentioned second linking part and above-mentioned second tilting face inclines Inclined plane part is configured to curved surface (technical scheme 2) with the above-mentioned 3rd linking part tilting face.

According to the planar illuminating device that this is described, by based on enter wedge portion, along away from entering light The light leak of the distance in face produces dangerous variation pattern and suitably sets the shape of inclined plane, it is possible to more Efficiently reduce light leak.

(3) planar illuminating device is characterised by, shines in the planar described in (1) or (2) item On the basis of bright device, it is a continuous curve surface (technical scheme 3) that above-mentioned inclined plane is monolithically fabricated.

According to the planar illuminating device that this is described, it is a continuous song owing to inclined plane is monolithically fabricated Face, therefore the direction that edge is orthogonal with incidence surface in arbitrary lateral section, the inclination angle of inclined plane is continuously Spatially change, it is possible to based on enter wedge portion, along the distance away from incidence surface light leak produce Raw dangerous variation pattern, suitably sets the shape of inclined plane, it is possible to more with higher degree of freedom For efficiently reducing light leak.

(4) planar illuminating device is characterised by, at the planar illuminating device described in (3) item On the basis of, above-mentioned continuous curve surface be above-mentioned incidence surface side convexly, above-mentioned outgoing plane side song concavely Face.(technical scheme 4).

According to the planar illuminating device that this is described, at the leaded light tending to lightening and narrow frame Plate enter in wedge portion, produce the dangerous typical side changed with the distance away from incidence surface for light leak Formula, is shaped so as to the most appropriate shape by inclined plane, it is possible to more effectively reduce light leak.

(5) planar illuminating device is characterised by, at the planar illuminating device described in (4) item On the basis of, it is S shape that above-mentioned continuous curve surface is formed as side-looking, has in above-mentioned second tilts face Flex point.(technical scheme 5).

According to the planar illuminating device that this is described, it is possible to easily and effectively formed above-mentioned the most proper Inclined plane when shape.

(6) planar illuminating device is characterised by, shines in the planar described in (1) or (2) item On the basis of bright device, above-mentioned first tilts the second inclination the facial and above-mentioned 3rd facial, above-mentioned inclines At least one in inclined plane part is made up of (technical scheme 6) multiple planes.

According to the planar illuminating device that this is described, it is possible to based on enter wedge portion, along away from entering light The light leak of the distance in face produces dangerous variation pattern and is readily formed the shape of inclined plane, it is possible to have Effect ground reduces light leak.

(7) planar illuminating device is characterised by, any one in (1)～(6) item is remembered On the basis of the planar illuminating device carried, above-mentioned inclined plane is arranged on above-mentioned outgoing plane side (technical scheme 7).

(8) planar illuminating device is characterised by, any one in (1)～(7) item is remembered On the basis of the planar illuminating device carried, at above-mentioned incidence surface and above-mentioned enter to be provided with thickness between wedge portion Spend constant par (technical scheme 8).

In accordance with the invention it is possible to provide the deterioration that will not produce the reduction of brightness and Luminance Distribution etc., And make the lightening planar illuminating device of injection part.

Accompanying drawing explanation

In Fig. 1, (a) is the main portion of the planar illuminating device illustrating an embodiment of the invention The side view divided, (b) is the side of the feature schematically showing the planar illuminating device shown in (a) View.

In Fig. 2, (a) and (b), (c) are for saying the concept of the light leak risk factor of the present invention Bright figure, is respectively schematically to illustrate the light quantity of first time incident illumination relative to inclined plane, incidence Angle, the figure of light leak risk factor.

Fig. 3 is to illustrate to enter towards inclined plane to illustrate the concept of the light leak risk factor of the present invention The light penetrated and the angle of light between centers and the figure corresponding to the distance in the inclined plane of constant angular width.

In Fig. 4, (a) and (b), (c) are for saying the concept of the light leak risk factor of the present invention Bright figure, is respectively schematically to illustrate the light quantity of second time incident illumination relative to inclined plane, incidence Angle, the figure of light leak risk factor.

Fig. 5 is the figure of the distribution of the light leak risk factor illustrating entirety with the shape entering wedge portion accordingly.

In Fig. 6, (a) is by multiple incident illuminations different from incident angle for conventional planar illuminating device The side view that illustrates together of light path, (b) is for the planar illuminating device shown in Fig. 1 (a) And the side view illustrated together with the light path of multiple incident illuminations different from incident angle.

Fig. 7 is the sectional view of the typical structure illustrating broken white LED.

Fig. 8 is the side-looking of the major part of the planar illuminating device illustrating other embodiments of the present invention Figure.

Fig. 9 is the side-looking of the major part of the planar illuminating device illustrating other embodiments of the present invention Figure.

In Figure 10, (a) is the main portion of the planar illuminating device illustrating other embodiments of the present invention The elevation divided, (b) is the sectional view of the line A-A along (a).

Label declaration

10,50,60,70: planar illuminating device；11:LED；20,51,61,71: guide-lighting Plate；21: incidence surface；The end edge of surface (including the face of the outgoing plane) side of 21c: incidence surface；21d: The end edge of the back side (including the face of the reflecting surface) side of incidence surface；22: outgoing plane；23: surface；24: The back side；25,65,75: inclined plane；25a, 65a, 75a: first tilts face；θ 1: the first Tilt the average slope angle of face；θ 2: the second tilts the average slope angle of face；θ 3: the three inclines The average slope angle of inclined plane part.

Detailed description of the invention

Hereinafter, referring to the drawings the planar illuminating device involved by embodiments of the present invention is illustrated. It addition, in appended each accompanying drawing, in order to make the present invention readily appreciate, be suitably greatly exaggerated to show each The shape of element, size etc..Further, in appended each accompanying drawing, when with two elements In the case of the mode of space contiguous illustrates, this space is to understand the present invention for convenience actually And insert or be greatly exaggerated to show, the structure of the present invention is not by adjacent element Between the presence or absence in space or the impact of size in this space during Existential Space.

As shown in (a) of Fig. 1, as the planar illuminating device 10 of first embodiment of the present invention Possess the LED11 as light source and the light for making LED11 be sent is the leaded light that penetrates of planar ground Plate 20.Light guide plate 20 uses transparent material (such as polycarbonate resin) to be formed as overlooking rectangular-shaped, At its outer surface, there is the end face for LED11 configuration that is incidence surface 21.Further, at light guide plate 20 In, with the long side direction of incidence surface 21 (being the direction orthogonal with paper in (a) of Fig. 1) Two end edge 21c, 21d in the bread that connects of end edge 21c of a side containing outgoing plane 22 and aftermentioned Inclined plane 25.Hereinafter, the face of the side comprising outgoing plane 22 of light guide plate 20 is referred to as surface 23, The face opposed with surface 23 is referred to as the back side 24.

Here, in the present invention, (will scheme towards the end face opposed with incidence surface 21 from incidence surface 21 Show omission) direction (the paper right direction in (a) of Fig. 1) be referred to as " front " (it is contrary Direction is referred to as " rear ").So " front " of definition is incident towards light guide plate 20 from incidence surface 21 Light as the direction directed in light guide plate 20 of entirety, from this aspect, it is also possible to will be based on upper Before and after stating definition, direction is referred to as " light conducting direction ".

Further, by from the back side 24 towards the direction on surface 23 (direction on the paper of (a) of Fig. 1) It is defined as " top " (its rightabout is defined as " lower section "), and by based on this definition upper and lower Direction is referred to as " thickness direction ".Additionally, by the direction orthogonal with fore-and-aft direction and above-below direction (with The direction that the paper of (a) of Fig. 1 is orthogonal) it is referred to as that (be defined as that face forward observes as required is " right Just ", " left ") left and right directions.In other words, left and right directions is the long side direction of incidence surface 21.And And, as long as no clearly explaining, then " length ", " thickness (thick) " and " width " is respectively Refer to the size on fore-and-aft direction, above-below direction and left and right directions.

Light guide plate 20 have towards front from incidence surface 21 side include inclined plane 25 enter wedge portion 31, With the injection part 32 including outgoing plane 22.And then, the back side 24 of light guide plate 20 be formed to pass into Wedge portion 31 and injection part 32, and form a tabular surface, on the other hand, enter inclining of wedge portion 31 Inclined-plane 25 is formed as, along with tilting downward from trend front, incidence surface 21 side, thus, entering wedge Portion 31 is formed as along with from trend outgoing plane 22 side, incidence surface 21 side, wall thickness is thinning.Outgoing plane 22 Be formed as the tabular surface that is substantially orthogonal with incidence surface 21 and the end edge 26 in the front with inclined plane 25 Connecting, the back side 24 is the most opposed with outgoing plane 22.

Secondly, with reference to (a) and (b) of Fig. 1 of Fig. 1, to the master as planar illuminating device 10 The structure wanting the inclined plane 25 entering wedge portion 31 of feature is described in detail.Here, (b) of Fig. 1 Illustrate that the planar illuminating device 10 shown in (a) of Fig. 1 light guide plate 20 enter wedge portion The feature of 31 and the side view that schematically shows.

It addition, in planar illuminating device 10, enter wedge portion 31 and incidence surface 21 and injection Orthogonal cross section, face 22 (is cut by being parallel to obtained by the cutting plane cutting of paper in (a) of Fig. 1 Face) cross sectional shape optional position on the long side direction of incidence surface 21 all with (a) institute of Fig. 1 The side view shown is identical.Thus, in the following description, shown in (a) and (b) based on Fig. 1 Side view common feature in such arbitrary cross section is illustrated.

Further, in the present invention, (the such as position, optional position in the inclined plane 25 in wedge portion 31 is entered Put P) the tiltangleθ p of the inclined plane 25 at place refers to: through position P and with incidence surface 21 with And the cross section that outgoing plane 22 is orthogonal is (for by the cutting plane cutting being parallel to paper in (a) of Fig. 1 Obtained by cross section.Hereinafter referred to as lateral section) in, from position P towards incidence surface 21 side and outgoing plane Ray K that 22 extend parallel to and tangentially prolonging towards incidence surface 21 side with inclined plane 25 from position P Angle between the ray L stretched (in other words as: with at the position P of inclined plane 25, through position The angle that rising slope in the lateral section of P is suitable).

In light guide plate 20, it is a continuous curve surface owing to inclined plane 25 is monolithically fabricated, therefore tilts The inclination angle in face 25 changes in spatiality in arbitrary lateral section the most continuously.

Wherein, the inclined plane 25 of light guide plate 20 is formed as its inclination angle and meets following condition.That is, incline Inclined-plane 25 is configured to: have (a) of first inclination face 25a(Fig. 1 from incidence surface 21 side successively In the scope shown in " I "), second tilt face 25b(Fig. 1 (a) in the model shown in " II " Enclose) and the 3rd tilt face 25c(Fig. 1 (a) in the scope shown in " III "), second inclines The average slope angle θ 2 of inclined plane part 25b tilts the average slope angle θ 1 of face 25a more than first, and And more than the average slope angle θ 3 of the 3rd inclination face 25c.Here, the determination scope of inclined plane 25 Average slope angle be to average in the inclination angle of position in the range of this scope is overall to this Obtained by angle.

Additionally, in the example of diagram, first and the 3rd tilts the average slope angle of face 25a, 25c θ 1, θ 3 are formed as less than the average slope angle in the length range entering wedge portion 31 of inclined plane 25 θ.In (b) of Fig. 1, it is shown that first, second, third inclination face 25a, 25b, 25c is each From the length range entering wedge portion 31 of average slope angle θ 1, θ 2, θ 3 and inclined plane 25 The example of average slope angle θ, illustrate simultaneously and make with each average slope angle θ 1, θ 2, θ 3, θ For the virtual plane 35a at inclination angle, 35b, 35c, 36.In (b) of Fig. 1, virtual plane 36 is suitable with the general inclined plane shape entering wedge portion in conventional planar illuminating device.

Further, in light guide plate 20, in the way of being integrally formed into a continuous curve surface, realize having One, second, third tilts the inclined plane 25 of face 25a, 25b, 25c, additionally, this continuous curve surface Be formed as along with the back side 24 side close from trend front, incidence surface 21 side, and incidence surface 21 side shape Becoming the curved surface of convex, outgoing plane 22 side is formed as concave curved surface.In the example of diagram, at Fig. 1 The side view (arbitrary side sectional shape) shown in (a) in, represent inclined plane 25 S word The curve of shape has flex point A in second tilts face 25b, and first tilts face 25a and second Flex point A of comparing tilting face 25b tilts the part of face 25a side convexly by first, and second inclines Flex point A of comparing of inclined plane part 25b tilts face by the second part tilting face 25c side and the 3rd 25c is concavely.

Secondly, with reference to Fig. 2～Fig. 6, the action effect of planar illuminating device 10 is illustrated.

First, to enter the inclined plane in wedge portion by the virtual plane 36 shown in (b) such as Fig. 1 that In the conventional planar illuminating device that the inclined plane with single tiltangleθ of sample is constituted, from inclination The characteristic of the light leak that face occurs illustrates relative to the interdependence of location in inclined plane.

It addition, in the following description, for convenience of description, for conventional planar illuminating device Inclined plane mark label 36, to carry out reference, then marks and planar illuminating device for other elements 10 identical labels are to carry out reference.

Think in the light inciding inclined plane 36, from entering wedge portion 31 and due to inclined plane 36 From the relative quantity entering the light of leakage near wedge portion 31 of outgoing plane 22, (hereinafter referred to as " light leak is endangered Danger degree " or referred to as " risk factor "), with amount (light quantity) and the court of the light towards inclined plane 36 incidence This angle (is referred to as " angle of incidence by the angle relative to optical axis when inclined plane 36 is incident in the present invention Degree ") between, there is the dependence shown in following formula.

" light quantity " × " incident angle "=" light leak risk factor "

Here, in the present invention, " optical axis " refers to from the beginning of the center of light-emitting area 11a of LED11 With light-emitting area 11a(thus also with incidence surface 21) central shaft that extends orthogonally.

Light leak risk factor why depend on incident angle be due in inclined plane 36 from light guide plate 20 The absorbance of the light of inside outward portion transmission depends on incident angle.And then, above-mentioned light quantity and angle of incidence It is substantially uniform with the incidence surface 21 of light guide plate 20 that degree depends on light-emitting area 11a(away from LED11) Distance in the direction of the optical axis.

Further, in the light guide plate 20 tending to slimming and narrow frame in recent years, it is incident to incline The light on inclined-plane 36 specifically includes that after inciding in light guide plate 20 from incidence surface 21 first towards inclination Light (hereinafter referred to as " incident illumination for the first time ") and the first time incident illumination of face 36 incidence are inclined by face 36 then reflected by the back side 24 and again towards inclined plane 36 incidence light (hereinafter referred to as " and second time enter Penetrate light ").Wherein, it is set as in first time incident illumination being additionally included in inciding light guide plate from incidence surface 21 Reflected by the back side 24 and the first light towards inclined plane 36 incidence after in 20.And, although there is also Again towards the light of inclined plane 36 incidence after being reflected more than twice by the back side 24, but with the most incident It is few that light, for the second time incident illumination compare light quantity, and the ratio occupied in light leak is few.

Here, the (a) and (b) of Fig. 2, (c) are relative to away from LED11 for first time incident illumination Distance in the direction of the optical axis be shown respectively the light quantity of light towards inclined plane 36 incidence, incident angle, The figure of the distribution of risk factor.It addition, the (a) and (b) of Fig. 2, (c) are for risk factor easy to understand Feature and the schematic diagram that illustrates.

First, light quantity is studied.It is that entirety penetrates radially and is incident to lead from LED11 The sensing distribution of the light in tabula rasa 20 is formed as: in the direction of the optical axis light quantity maximum and along with optical axis Between angle increase and light quantity reduce distribution.Wherein, as it is shown on figure 3, with LED11's The center of light-emitting area 11a is that the width of the inclined plane 36 that the unit angle of starting point is corresponding (is equivalent to optical axis The width D in direction) be formed as: light is the longest the closer to the most above-mentioned width of optical axis direction, light and light Angle the most above-mentioned the biggest width between axle is the shortest (D1 ＜ D2 ＜ D3).Thus, such as (a) of Fig. 2 Shown in, the light quantity towards per unit distance (unit are) of inclined plane 36 incidence is formed as: close The region of incidence surface 21, increases along with the distance away from LED11 and becomes big, is reaching peak value (greatly Region) reversion afterwards, increase along with the distance away from LED11 and reduce.

Secondly, incident angle is studied.As shown in (b) of Fig. 2, incident towards inclined plane 36 The incident angle of light there is width (scope) corresponding with the distance away from LED11, this scope upper Limit value increases along with the distance away from LED11 and diminishes, and thus, the distance away from LED11 is the biggest, then Absorbance at inclined plane 36 is the least.

Thus, as shown in (c) of Fig. 2, light leak risk factor (the higher limit phase of light quantity and incident angle Value obtained by taking advantage of) the distance away from LED11 be zero greatest around, comparing this point on the front Position increases along with the distance away from LED and reduces.

Secondly, with reference to Fig. 4, second time incident illumination is studied.The (a) and (b) of Fig. 4, (c) are It is respectively relative to the distance away from LED11 illustrates towards inclined plane 36 incidence for second time incident illumination The light quantity of light, incident angle, the figure of distribution of risk factor.It addition, the (a) and (b) of Fig. 4, (c) It it is the schematic diagram illustrated for the feature of risk factor easy to understand.

First, light quantity is studied.As shown in (a) of Fig. 4, the light quantity of incident illumination for the second time It is distributed in comparing for the first time incident illumination position on the front and have the distribution in peak value (very big region). Secondly, the incident angle of second time incident illumination is studied by (b) with reference to Fig. 4.For incidence The higher limit of angle, due to angle change (the incident angle change when inclined plane 36 occurs reflection for the first time Greatly about 2 times of the tiltangleθ of inclined plane 36), therefore the higher limit of incident angle is in making The distribution of incident illumination is the distribution of its angle variable quantity overlapping on the basis of moving forward.Further, The lower limit of incident angle be corresponding with the distance away from LED11 on the occasion of, this lower limit and higher limit Equally, there is the biggest trend that then its value is the least of the distance away from LED.

Thus, as shown in (c) of Fig. 4, the light leak risk factor of incident illumination is substantially shaped as the second time The distribution making for the first time light leak risk factor of incident illumination move forward after distribution.But, according to , there is the light leak danger of second time incident illumination in the once difference of the angle variable quantity when inclined plane 36 reflects Danger degree is more than the probability of the light leak risk factor of incident illumination for the first time.

Leakage by the light leak risk factor of first time incident illumination that obtains in the above described manner with second time incident illumination Risk factor obtained by the addition of light risk factor is formed as the light leak risk factor of inclined plane 36 entirety (with reference to figure 5).As it is shown in figure 5, in the little position of the distance away from LED11 (near the position of incidence surface 21) There is the big part of light leak risk factor (part in maximum), along with away from LED11 from this position Distance increase and light leak risk factor is gradually lowered.Additionally, when the distance away from LED11 becomes big, Light leak risk factor inverts and becomes larger, and again presents maximum.It is integrally formed as central part recessed The concave shape of shaped form.

As it has been described above, the present application is to include maximum in view of overall light leak risk factor is divided into Two regions (the very big region of incidence surface 21 side and the very big region of outgoing plane 22 side) and include pole The situation in one region of little value (very small region of central authorities) and complete, entering inclining of wedge portion 31 The scope suitable with the very big region of the plane of incidence 21 side and outgoing plane 22 side respectively on inclined-plane 25 sets respectively Put the first inclination face 25a and the 3rd and tilt face 25c, at the model suitable with the very small region of central authorities Enclose and the second inclination face 25b is set, and make the first inclination face 25a and the 3rd tilt face 25c Average slope angle θ 1 and θ 3 compare the average slope angle θ 2 of the second inclination face 25b relatively Little, thus it is effectively reduced the light leak occurred in inclined plane 25.

In planar illuminating device 10, based on above-mentioned way, it is possible to increase from outgoing plane 22 injection The brightness of illumination light.

Additionally, in planar illuminating device 10, by being shaped so as to inclined plane 25 near entering The side-looking that the region of bright finish 21 is formed as projection, the region of close outgoing plane 22 is formed as caving in is S The continuous curve surface of shape, it is possible to realize optimal inclined plane shape according to the distribution of overall light leak risk factor Shape, in order to reduce the light leak from inclined plane 25.

Additionally, as shown in Figure 6, it is constant possessing inclination angle throughout the whole region entering wedge portion 31 Inclined plane 36 conventional planar illuminating device (with reference to (a) of Fig. 6) in, from LED11 edge The direction injection result big with the angle of its optical axis incides inclined plane 36 with bigger incident angle The light L1 in region (I) of close incidence surface 21, as second time incident light beam strikes to inclined plane The region (III) of the close outgoing plane 22 of 36, the danger producing light leak at this is higher, additionally, root Different according to condition, this reflection light component easily between inclined plane 36 and the back side 24 interreflection and from Entering of outgoing plane 22 is penetrated near wedge portion 31.In conventional planar illuminating device, due to this Light leak, the problem that the uniformity of the Luminance Distribution producing the illumination light from outgoing plane 22 injection is deteriorated.

On the other hand, in the planar illuminating device 10 of present embodiment, by relatively reducing first Tilt face 25a and the 3rd and tilt the average slope angle θ 1 and θ 3 of face 25c, such as Fig. 6 Shown in (b), even if with the condition identical with above-mentioned L1 towards inclined plane 25 incidence light (as Mark label L1), also will not penetrate near wedge portion 31 from entering of outgoing plane 22, it is possible to by its court Guide in injection part 32.

In planar illuminating device 10, it is arranged such the illumination that can also improve from outgoing plane 22 injection The uniformity of the Luminance Distribution of light.

Further, this feature of planar illuminating device 10 is so-called broken white LED at LED11 In the case of particularly prove effective.Generally, as it is shown in fig. 7, broken white LED possesses to be scattered with Huang The transparent resin 42 of color fluorophor seals the structure of blue-light-emitting chip 41, by blue-light-emitting chip The colour mixture of the sodium yellow that the yellow fluorophor of 41 blue lights sent and this blue light of absorption sends, it is achieved Seem white luminescent spectrum.Now, from LED11 along the direction big with the angle of its optical axis At transparent resin compared with light L2, L3 of direction injection little with the angle of optical axis with edge for the light L1 of injection The distance passed through in 42 is longer, therefore there is the tendency becoming the white light with yellow sensation.Thus, With reference to (a) of Fig. 6 as it has been described above, come from the light leak of light L1 and easily enter wedge from outgoing plane 22 Injection near portion 31, this situation becomes and causes due to this light leak illumination light to be felt with yellow partly The reason of problem.

Thus, in planar illuminating device 10, reduce entering near wedge portion 31 from outgoing plane 22 Light leak can reduce or eliminate the problems referred to above, it is possible to play the effect of Colour improving illumination light Really.

According to the investigation/research of the present inventor, in the planar illuminating device 10 of present embodiment, with Compare at the conventional planar illuminating device entering wedge portion 31 and having the constant inclined plane in inclination angle 36, The light leak produced because of inclined plane 25 can reduce about 25%.Further, verified by real machine, really Recognize the brightness from the illumination light of outgoing plane 22 injection and improve 4.5%.

Additionally, in planar illuminating device 10, the part being connected with outgoing plane 22 of inclined plane 25 is also I.e. the 3rd average slope angle θ 3 constant inclination less than conventional inclined plane 36 tilting face 25c Angle θ, therefore, it is possible to suppression is due to inclined plane 25 with outgoing plane 22 with certain intersecting angle ground not Continuously coupled and the brightness disproportionation (the drastically change of brightness) that produces.And then, filled by planar light Put the inclined plane 25 of 10 to tilt be formed as concavity at face 25c and make and outgoing plane 22 the 3rd The inclination angle of the part connected is less than average slope angle θ 3, and this inhibition becomes apparent from.

Further, in planar illuminating device 10, due to the part of the close incidence surface 21 of inclined plane 25 That is first average slope angle θ 1 constant the inclining less than conventional inclined plane 36 tilting face 25a Bevel angle θ, therefore, will be provided with the flexible printed circuit board (FPC) (diagram is omitted) of LED11 In the case of being directly fixed in the inclined plane 25 of light guide plate 20, it is possible to reduce the luminescence of LED11 Face 11a is relative to the defect of the LED11 installation such as incidence surface 21 inclination of light guide plate 20.

Further, due to by the second maximum for three average slope angles tilted in face inclination face 25b It is configured at the central part of light conducting direction, therefore, even if tilting face 25b from second to produce light leak, logical The light-blocking member also often being able to utilize the top being configured at inclined plane 25 reliably absorbs this light leak.

It addition, in the example shown in (a) of Fig. 1, it is illustrated that inclined plane 25 is formed along it The length direction (fore-and-aft direction) entering wedge portion 31 has flex point A and male portion at approximate centre The shape situation the most consistent with the shape of concave portion, but in the present invention, the shape of inclined plane 25 Certainly it is not limited to such there is symmetric situation.In planar illuminating device 10, relative to Enter the first inclination face 25a of the total length in wedge portion 31, the second inclination face 25b and the 3rd inclination The ratio of length of face 25c and first tilts face 25a, second tilts face 25b and the Three inclination face 25c respective average slope angle θ 1, θ 2, θ 3 are the realities according to light leak risk factor The distributions on border etc. suitably set.Such as, the position of flex point A can be not arranged in along entering wedge portion The approximate centre of the length direction of 31, can be partial to outgoing plane 22, it is also possible to be set so that protuberance Area more than the area of recess.Furthermore it is preferred that from incidence surface 21 to flex point A in length Distance on direction is about 1.4 times (more than 1.1 times and less than 1.7 times of the thickness of incidence surface 21 In the range of).

For inclined plane 25 structure in the case of making flex point A be located proximate to outgoing plane 22, below Enumerate a preferred example.Such as, when the thickness for incidence surface 21 be 0.58mm, injection part 23 In the case of the light guide plate 20 of a length of 1.1mm that thickness is 0.4mm, enter wedge portion 31, will First, second and the 3rd tilt face 25a, 25b, 25c length be respectively set as 0.4mm, 0.4mm and 0.3mm, and, by first, second and the 3rd tilt face 25a, 25b, The average slope angle θ 1 of 25c, θ 2, θ 3 are respectively set as 6.4 °, 13 ° and 8.2 ° and (tilt Average slope angle θ in the length range in face 25 is 9.3 °).

Here, the planar illuminating device of the present invention can planar illuminating device 50 as shown in Figure 8 such At the incidence surface 21 of light guide plate 51 and enter to arrange between wedge portion 31 in the 33(Fig. 8 of par " IV " Shown scope).Par 33 has to tilt face 25a with first connect from incidence surface 21c extension Connect and the upper surface 52 parallel with outgoing plane 22, and there is constant thickness.

Further, the planar illuminating device of the present invention can also planar illuminating device 60 as shown in Figure 9 Like that, the first inclination face 65a, the second inclination face 65b and the 3rd of inclined plane 65 are tilted Face 65c is respectively formed as having constant tiltangleθ 1, θ 2, the inclined plane of θ 3.In other words, Planar illuminating device 60 has by virtual plane 35a, 35b, the 35c shown in (b) of Fig. 1 respectively The structure realized as actual inclined plane.The advantage of planar illuminating device 60 is to compare It is readily formed the inclined plane 65 of the present invention.

Further, planar illuminating device 60 can be made up of the first inclination face 65a and second inclination curved surface The linking part 66 and the second inclination face 65b and the 3rd of face 65b tilts the link of face 65c Any one party in portion 67 or two sides.Additionally, in planar illuminating device 60, can by first, The inclination face of more than 1 in second, third inclination face 65a, 65b, 65c is by having mutually Multiple inclined planes at different inclinations angle are constituted, at this time it is also possible to by the link to each other of each inclined plane The linking part of more than 1 in portion is configured to curved surface.

Here, in the above embodiment, whichsoever embodiment, enter wedge portion 31 with The cross sectional shape in incidence surface 21 and the orthogonal cross section (lateral section) of outgoing plane 22 is all formed as entering The arbitrary position of the long side direction of bright finish 21 is the most identical, thus, inclined plane 25,65 does not exists Inclination along the long side direction of incidence surface 21.But, in the planar illuminating device of the present invention, enter light The shape of the inclined plane in wedge portion can also be the shape of the inclination with the long side direction along incidence surface 21.

Figure 10 is the figure of the example illustrating such planar illuminating device 70, and (a) is from incidence surface 21 The front view (elevation) of planar illuminating device 70 is observed in side, and (b) is the A-A along (a) The sectional view of line.In planar illuminating device 70, the incidence surface 21 of light guide plate 71 is configured to its thickness Long side direction along incidence surface 21 spatially changes.Specifically, the thickness of incidence surface 21 It is configured to: the thickness at the allocation position of each LED11 and the thickness that thickness is equal extent of LED11 Degree, the thickness of the allocation position both sides of each LED11 is thicker than the thickness at the allocation position of LED11, And inclined plane 75 be configured to along the whole width range of long side direction of incidence surface 21 from incidence surface 21 is the most downward-sloping and be connected with outgoing plane 22 in the forward end of inclined plane 75.

Thus, inclined plane 75 not only has along the longitudinal direction the inclination of (light conducting direction), also has edge The inclination of left and right directions (long side direction of incidence surface 21).According to this structure, entering of inclined plane 75 Average slope angle in the length range in wedge portion 31 also with minimum at the allocation position of each LED, The mode maximum in the both sides of the allocation position of each LED11 along the long side direction of incidence surface 21 in space Upper variation.Wherein, in planar illuminating device 70, it is with planar illuminating device 10 something in common, In the lateral section of any position on the long side direction of incidence surface 21, second tilts face 75b The average slope angle in this lateral section more than first inclination face 75a and the 3rd tilt face The average slope angle in cross section, the same side of 75c.Additionally, planar illuminating device 70 is also formed as: In the lateral section of any position on the long side direction of incidence surface 21, first tilts face 75a And the 3rd tilt the average slope angle in any lateral section of face 75c less than in cross section, the same side The length range entering wedge portion 31 in average slope angle.

According to above structure, planar illuminating device 70 plays the work identical with planar illuminating device 10 By effect, inclined plane 75 also has the inclination of the long side direction along incidence surface 21 in addition, therefore, incites somebody to action It is incident to the light of inclined plane 75 parallel with outgoing plane 22 while there is the incident angle width of thickness direction Direction on also there is the mode of extension carry out reflecting as a result, can reduce from this inclined plane 75 Reflection light reflected by the back side 24 and again towards inclined plane 75(be typically the case the 3rd inclination face 75c) incident angle during incidence, therefore, it is possible to more effectively reduce from inclined plane 75 and injection Face 22 enter the light leak near wedge portion 31.

It addition, in planar illuminating device 70, enter the length long limit along incidence surface 21 in wedge portion 31 Direction is constant, but in planar illuminating device involved in the present invention, by making the length into wedge portion 31 Spend the long side direction along incidence surface 21 spatially to change, it is possible to set in the inclined plane entering wedge portion 31 Count out the inclination of long side direction along incidence surface 21.In this case, shine with the planar shown in Figure 10 Bright device 70 is compared, it is possible to by inclined plane average slope angle in the length range entering wedge portion 31 , along incidence surface 21 long side direction space variation suppress less.

Here, in the above-described embodiment, inclined plane 25,65,75 all shapes in wedge portion 31 are entered Become in the side, surface 23 of light guide plate 20,51,61,71, but at planar light involved in the present invention In device, inclined plane 25,65,75 can also be formed at the back side of light guide plate 20,51,61,71 24 sides.Or, planar illuminating device involved in the present invention can also light guide plate 20,51,61, The side, surface 23 of 71 and the back side 24 side both sides have the inclined plane into wedge portion 31, two inclined planes In any one party or two sides be configured to inclined plane 25,65,75 involved in the present invention.Now, When the feelings that only side in two inclined planes is configured to inclined plane 20,65,75 involved in the present invention Under condition, it is also possible to it is as in the past that the inclined plane of the opposing party is formed as there is constant inclination angle Inclined plane.

Further, when the FPC being provided with LED11 being arranged in light guide plate 20,51,61,71 In surface 23 and the back side 24 be provided with inclined plane (inclined plane involved in the present invention 25,65, 75 or conventional inclined plane) side, face in the case of, it is also possible to the inclined plane being arranged on this side, face It is integrally provided the pedestal for configuring FPC.It is each that this pedestal is such as arranged on from incidence surface 21 The prescribed limit that the side, left and right of the allocation position of LED11 extends forward (almost cannot by preferably light Incident scope).

Planar illuminating device involved in the present invention certainly include possessing by with above-mentioned single embodiment The planar illuminating device of the structure of each feature combination in any of association explanation.Such as, planar is shone Bright device 10,60,70 can also possess the par 33 associating explanation with planar illuminating device 50.

Claims (5)

1. a planar illuminating device, possesses light source and light guide plate, and this light guide plate has for this light source The incidence surface of configuration and make the outgoing plane from the incident light injection of this incidence surface,

Above-mentioned planar illuminating device is characterised by,

Above-mentioned light guide plate has into wedge portion, and this enters wedge portion and includes inclined plane, and be arranged to along with from Above-mentioned incidence surface side tends to above-mentioned outgoing plane side and wall thickness is thinning, and above-mentioned inclined plane is from above-mentioned incidence surface side Rise and there is the first inclination face, the second inclination face and the 3rd inclination face, above-mentioned second inclined plane Optional position in portion, the long side direction that is located at above-mentioned incidence surface and above-mentioned incidence surface and above-mentioned Average slope angle in the cross section that outgoing plane is orthogonal tilts more than above-mentioned first in same above-mentioned cross section Facial and above-mentioned 3rd tilt face average slope angle, wherein, above-mentioned enter the above-mentioned of wedge portion incline The inclination angle of the above-mentioned inclined plane of any position on inclined-plane refers to: through this position and with above-mentioned In incidence surface and the orthogonal cross section of above-mentioned outgoing plane, penetrate with above-mentioned from this position towards above-mentioned incidence surface side The ray that extends parallel to and from this position towards above-mentioned incidence surface side with above-mentioned inclined plane tangentially The interradial angle extended, the average slope angle of the determination scope of above-mentioned inclined plane is whole in this scope Body is averaged in the inclination angle of the position in the range of this obtained by angle,

It is a continuous curve surface that above-mentioned inclined plane is monolithically fabricated,

It is S shape that above-mentioned continuous curve surface is formed as side-looking, has flex point in above-mentioned second tilts face,

Above-mentioned continuous curve surface is from above-mentioned incidence surface distance in the longitudinal direction to above-mentioned flex point For the thickness of above-mentioned incidence surface more than 1.1 times less than 1.7 times.

Planar illuminating device the most according to claim 1, it is characterised in that

Above-mentioned first tilts the facial and above-mentioned second linking part tilting face and above-mentioned second tilts Facial and above-mentioned 3rd linking part tilting face is configured to curved surface.

Planar illuminating device the most according to claim 1 and 2, it is characterised in that

Above-mentioned continuous curve surface be above-mentioned incidence surface side convexly, above-mentioned outgoing plane side curved surface concavely.

Planar illuminating device the most according to claim 1 and 2, it is characterised in that

Above-mentioned inclined plane is arranged on above-mentioned outgoing plane side.

Planar illuminating device the most according to claim 1 and 2, it is characterised in that

At above-mentioned incidence surface and above-mentioned enter to be provided with the par of constant thickness between wedge portion.