WO2009107533A1 - 平面光源装置および分断プリズム用金型の製造方法 - Google Patents
平面光源装置および分断プリズム用金型の製造方法 Download PDFInfo
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- WO2009107533A1 WO2009107533A1 PCT/JP2009/052834 JP2009052834W WO2009107533A1 WO 2009107533 A1 WO2009107533 A1 WO 2009107533A1 JP 2009052834 W JP2009052834 W JP 2009052834W WO 2009107533 A1 WO2009107533 A1 WO 2009107533A1
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- light
- guide plate
- prism
- light guide
- light source
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- 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
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
- G02B6/0036—2-D arrangement of prisms, protrusions, indentations or roughened surfaces
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- 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
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
- G02B6/0038—Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
-
- 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
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
- G02B6/0053—Prismatic sheet or layer; Brightness enhancement element, sheet or layer
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/1336—Illuminating devices
- G02F1/133615—Edge-illuminating devices, i.e. illuminating from the side
Definitions
- the present invention relates to a flat light source device usable for a liquid crystal display device or the like.
- Patent Document 1 discloses an autostereoscopic image display device. As shown in FIG. 1A of Patent Document 1, the display device includes a light guide plate 2, light sources 1 a and 1 b disposed on the light incident surfaces on both sides of the light guide plate 2, and the light emission surface side of the light guide plate 2.
- the light incident surface on the light guide plate 2 side has a triangular prism array extending in a direction parallel to the light incident surface of the light guide plate 2, and the light exit surface opposite to the light guide plate 2 side has
- the double-sided prism sheet 3 having a semi-cylindrical lens array extending parallel to the triangular prism array, the transmissive display panel 4 disposed on the light exit surface side of the double-sided prism sheet 3, and the transmissive display panel 4 are alternately arranged.
- Synchronous driving means 5 that drives the light sources 1a and 1b to be turned on in synchronization with the displayed left and right parallax images, and emits light from the light sources 1a and 1b from the transmissive display panel 4 at angles corresponding to the left and right parallaxes, respectively. Is provided.
- Patent Document 2 discloses a backlight device that emits linearly polarized light using a reflective polarizing plate in order to increase the brightness of a liquid crystal display device.
- the backlight device includes a light guide plate 101b, a reflective polarizing plate 102 disposed on the light exit surface side of the light guide plate 101b, and a light exit surface opposite to the light exit surface of the light guide plate 101b.
- positioned at the back surface side of the phase difference plate 104 are provided.
- the light utilization efficiency is improved by converting the light into linearly polarized light along the transmission axis of the reflective polarizing plate 102 and transmitting it through the reflective polarizing plate 102.
- Patent Document 3 also discloses a backlight device similar to Patent Document 2.
- Patent Documents 4 and 5 disclose backlight devices in which a diffraction grating that scatters light with good directivity is formed on a light guide plate.
- a diffraction grating that scatters light with good directivity is formed on a light guide plate.
- this backlight device since light is reflected by the diffraction phenomenon by the diffraction grating, there is a problem in that the direction of diffraction differs depending on the wavelength, thereby causing color breakup due to the difference in wavelength. Further, there is no description about the polarization state of the light emitted from the light guide plate, and it is not known whether a large amount of polarized light that can be effectively used in the liquid crystal panel can be extracted.
- the present invention has been made to solve the above-described problems, and is a planar light source capable of improving the light utilization efficiency and preventing color breakup without using a reflective polarizing plate and without performing multiple reflection.
- the object is to provide a device.
- the planar light source device is formed on a flat light guide plate, a light source disposed opposite to at least one of both end faces of the light guide plate, and a back surface inside the light guide plate, A splitting prism that reflects light incident on the light guide plate from the light source to the front side of the light guide plate, and the split prism is split into a prism portion having a width approximately equal to the wavelength of the light of the light source.
- the prism portion and the divided portion are alternately and repeatedly formed along a direction parallel to the end face of the light guide plate facing the light source.
- a planar light source device includes a flat light guide plate, a light source light guide plate disposed to face at least one of both end surfaces of the light guide plate, and at least one end surface of the light source light guide plate.
- a light source disposed opposite to the light source, a reflection prism formed on the back surface inside the light guide plate and extending in a direction parallel to the light source light guide plate, and a surface opposite to the surface facing the light guide plate inside the light source light guide plate
- a splitting prism configured to reflect light incident on the light source light guide plate from the light source to a surface facing the light guide plate, each of the split prisms being approximately the same as the wavelength of the light of the light source.
- the prism portion and the divided portion are alternately and repeatedly formed along a direction parallel to the end face of the light guide plate facing the light source. Than is.
- the splitting prism has a prism portion and a splitting portion each having the same width as the light wavelength of the light source, and is an end face facing the light source in the light guide plate. Since the prism portion and the divided portion are alternately formed along the direction parallel to the vertical direction, the reflected light reflected by the divided prism is converted into vertically polarized light (polarized light perpendicular to the ridge line direction of the divided prism 11). Rather than parallel polarized light (polarized light parallel to the ridge line direction of the dividing prism 11). In other words, the reflected light can be converted into light having a high degree of polarization. As a result, the light utilization efficiency can be improved without using a reflective polarizing plate and without performing multiple reflection. Further, since the diffraction phenomenon is not used, color breakup can be prevented.
- the reflected light reflected by the dividing prism is converted into vertically polarized light (perpendicular to the ridge line direction of the dividing prism 110). It is possible to make the light that contains much more parallel polarized light (polarized light parallel to the ridge line direction of the dividing prism 110) than the polarized light (that is, the reflected light can be made light with a high degree of polarization). As a result, the light utilization efficiency can be improved without using a reflective polarizing plate and without performing multiple reflection. Further, since the diffraction phenomenon is not used, color breakup can be prevented.
- FIG. 1 is a schematic configuration diagram (perspective view) of a planar light source device 1 according to Embodiment 1.
- FIG. 1 is a side view of a planar light source device 1 according to Embodiment 1.
- FIG. It is a top view of the light-guide plate 3 of FIG.
- FIG. 4 is a cross-sectional view of the light guide plate 3 of FIG. 1 taken along the line IV-IV. It is a figure explaining the model of the light-guide plate 3 used by reflection simulation.
- FIG. 6 is a diagram illustrating a simulation result when incident angles of incident light are set to 10 degrees, 20 degrees, and 30 degrees in the dividing prism 11. It is the figure which showed the simulation result when the incident angle of incident light is 10 degree
- FIG. 5 is a schematic configuration diagram (perspective view) of a split prism mold 15;
- FIG. 11 is a schematic cross-sectional view taken along the line XI-XI in FIG. 10. It is a figure explaining the manufacturing method of the metal mold
- the diagrams on the right side of (a) to (d) are side views from the P direction of the diagram on the left side. It is a side view of the planar light source device 1B which concerns on Embodiment 3.
- FIG. It is a figure explaining the incident angle to the light-projection surface of the light-guide plate 3 of the reflected light 10a by the division
- FIG. It is a figure explaining the reflectance in the interface of the inside of the light-guide plate 3, and the exterior (air layer) of the reflected light 10a by the division
- FIG. It is the structure schematic (plan view and side view) of 1 C of planar light source devices which concern on Embodiment 4.
- Embodiment 1 FIG. ⁇ Overall configuration>
- the flat light source device 1 according to this embodiment can be used as a backlight device of a liquid crystal display device, for example, and the configuration thereof is shown in FIGS. 1 is a perspective view of the flat light source device 1, FIG. 2 is a side view, FIG. 3 is a plan view, and FIG. 4 is a cross-sectional view taken along line IV-IV shown in FIG.
- the planar light source device 1 includes a light guide plate 3, light sources 5 a and 5 b disposed opposite to both end surfaces (light incident surfaces) of the light guide plate 3, and the front surface of the light guide plate 3 (light
- the phase difference plate 7 affixed to the emission surface and the reflection sheet 9 disposed on the back surface of the light guide plate 3 are provided.
- a liquid crystal panel 13 of the liquid crystal display device is disposed on the front side of the light exit surface of the light guide plate 3.
- the light guide plate 3 is formed, for example, in a rectangular flat plate shape by a transparent member such as a transparent resin, and one or more divided prisms 11 are formed on the inner back surface.
- the split prism 11 has a prism portion 11a having a width d1 and a width d2 that are approximately the same as the light wavelengths of the light sources 5a and 5b, and a split portion (that is, a part of the light guide plate 3) 11b.
- the prism portions 11a and the divided portions 11b are alternately and repeatedly formed along a direction parallel to the surface.
- the dividing prism 11 is an isosceles triangular prism in which the base side surface of the isosceles triangle is disposed on the back surface of the light guide plate 3 and intermittently in the ridgeline direction of the apex angle of the isosceles triangle.
- the prism portion 11a and the divided portion 11b are alternately and repeatedly formed.
- the dividing prism 11 is configured as a prism aggregate in which a plurality of thin isosceles triangular prisms 11a are arranged in parallel at predetermined vertexes 11b in the ridgeline direction of their apex angles.
- the ridgeline direction of the apex angle is a direction parallel to the light incident surface of the light guide plate 3.
- a plurality of the dividing prisms 11 are arranged on the back surface inside the light guide plate 3 vertically and horizontally (that is, in the ridgeline direction of the apex angle and in the orthogonal direction of the ridgeline direction) with appropriate intervals d4 and d5. It should be noted that the luminance of the planar light source device 1 can be adjusted by adjusting the interval (luminance adjustment interval) d5 in the ridge line direction of the apex angle.
- the total length in the ridge line direction of the apex angle (that is, the length in the repeating direction of the prism portion 11a and the dividing portion 11b) d0 is set to 1 ⁇ m to 50 ⁇ m, and the apex angle is set to 100 degrees.
- the base angle is set to 40 degrees
- the base length d9 of the isosceles triangle is set to 4 ⁇ m which is sufficiently longer than the wavelength of light
- the width d1 of the prism portion 11a is set to 0.4 ⁇ m
- the divided portion 11b the divided portion 11b.
- the width d2 is set to 0.4 ⁇ m
- the repetition pitch d3 between the prism portion 11a and the divided portion 11b is set to 0.8 ⁇ m
- the height d10 of the divided prism is set to 3 ⁇ m.
- the pitch d4 between the ridge lines of the adjacent dividing prisms 11 is set to 5 ⁇ m
- the brightness adjustment interval d5 is set to 10 ⁇ m to 100 ⁇ m.
- the light 10 from the light source 5 a enters the light guide plate 3 from the light incident surface of the light guide plate 3, and the inner surface of the light guide plate 3. Then, the light is propagated while being reflected, and is incident on the prism surface of the dividing prism 11 at a certain point, and is separated into reflected light 10a reflected by the prism surface and transmitted light 10b transmitted through the prism surface.
- the reflected light 10a is more parallel polarized (the direction of the ridge line of the divided prism 11) than the vertically polarized light (the polarized light perpendicular to the ridge direction of the divided prism 11). (Polarized light parallel to the light).
- the reflected light 10a is reflected by the prism surface, exits from the light exit surface of the light guide plate 3, passes through the phase difference plate 7, rotates its polarization in a predetermined direction, and irradiates the liquid crystal panel 13. .
- the reflected light 10a from the dividing prism 11 is reflected at a reflection angle of 45 degrees.
- the liquid crystal panel 13 is illuminated by being reflected in a direction substantially perpendicular to the light exit surface.
- the phase difference plate 7 is a half-wave plate, and the slow axis is affixed at an angle of 22.5 degrees with respect to the direction parallel to the ridge line direction of the dividing prism 11, and the reflected light 10a is parallel.
- the polarized light changes to polarized light having an angle of 45 degrees with respect to a direction parallel to the ridge line direction of the dividing prism 11.
- the polarized light in this direction is highly efficient for twisted nematic type liquid crystal panels.
- the transmitted light 10b passes through the dividing prism 11, propagates while being reflected again by the inner surface of the light guide plate 3 and the reflection sheet 9, and repeats reflection and transmission at the dividing prism 11.
- the transmitted light 10b contains a lot of parallel polarized light in the reflected light 10a, and conversely contains a lot of vertical polarized light.
- the polarization state of the transmitted light 10b changes during propagation due to the birefringence of the light guide plate 3 and the phase difference plate 7, and the reduced horizontal polarization increases again to be close to natural light. Therefore, even when the transmitted light 10b is reflected again by the subsequent splitting prism 11, the reflected light contains a large amount of parallel polarized light.
- the dividing prism 11 is an isosceles triangle (that is, symmetrical with respect to the light incident surfaces on both sides of the light guide plate 3), the light from the light source 5b behaves similarly to the light from the light source 5a. Accordingly, similarly to the light source 5a, polarized light can be radiated effectively from the light of the light source 5b, so that high-luminance illumination is possible with high light utilization efficiency.
- planar light source device 1 As described above, in the planar light source device 1, light with a high degree of polarization (light with a considerably high proportion of light in a specific polarization state) is emitted.
- the dividing prism 11 is an isosceles triangle. However, when light is incident only from one end face of the light guide plate 3.
- the dividing prism 11 may be an unequal triangle.
- the dividing prism 11 may not be a triangular prism, but may be a prism having a shape such as a cylindrical lens. Generally, a prism surface extending parallel to the light incident surface of the conductor plate 3 is used.
- the structure is not particularly limited as long as it is a structure in which prism portions and divided portions are alternately repeated in the direction extending in parallel.
- the dividing prism 11 is not filled in the entire back surface of the light guide 3, but is arranged at an appropriate interval. Moreover, the dividing prism 11 does not necessarily need to be regularly arranged vertically and horizontally as shown in FIG.
- FIG. 5 shows a model of the light guide plate 3 used in the reflection simulation of the dividing prism 11.
- the refractive index n of the light guide plate 3 is set to 1.5.
- the dividing prism 11 has a total length d0 in the ridge line direction of the apex angle set to 5 ⁇ m (note that the value of d0 may be any value within the range of 1 ⁇ m to 50 ⁇ m, for example), and each prism portion 11a has an isosceles triangular prism shape.
- one of the two directions perpendicular to the light incident surface of the light guide plate 3 is set as the 0 ° direction, and the other direction is set as the 180 ° direction.
- An orthogonal upward direction is set as a 90-degree direction.
- a plane wave having a predetermined polarization state is incident on the light guide plate 3 from the 0 degree direction, and the relative light intensity of the reflected light 10 a reflected by the dividing prism 11 (that is, the light intensity of the reflected light 10 a with respect to the light intensity of the incident light 10).
- a wave optics simulation to measure was performed.
- a parallel polarized plane wave having a wavelength of 0.54 ⁇ m and having an oscillation direction of an electric field in a direction parallel to the ridge line direction of the splitting prism 11 is incident, and a case where the wavelength is 0.54 ⁇ m and the splitting prism 11
- the simulation was performed in the case where a vertically polarized plane wave having an oscillation direction of the electric field was incident in a direction perpendicular to the ridge line direction.
- FIG. 6 shows the result of the above simulation.
- the relative luminous intensity (that is, reflectance) of the reflected wave 10a is 10 times higher when the incident light 10 is parallel polarized light than when it is vertically polarized light. It can be seen that it is twice as large. From this fact, it can be seen that when non-polarized light is incident on the light guide plate 3, the reflected light 10a by the dividing prism 11 contains more parallel-polarized light than vertically-polarized light.
- the difference in the relative luminous intensity of the reflected light 10 a between the case where the incident light 10 is parallel polarized light and the case where the incident light 10 is vertically polarized light is the wavelength of the incident light formed on the dividing prism 11. It can be seen that this is a phenomenon caused by the repetitive structure of the prism portion 11a and the divided portion 11b having the widths d1 and d2 close to.
- the ratio of the relative luminous intensity of the reflected light 10a in the case of parallel polarization to that of vertical polarization is about 100 in the case of A and about 1.5 in the case of B.
- the width d1 of the prism portion 11a, the width d2 of the divided portion 11b, and the repetition pitch d3 thereof for example, smaller than in the case of the above B, the reflected light 10a is more parallel polarized light than vertical polarized light. It can be seen that it can be made into light containing a large amount of light (ie, light having a high degree of polarization).
- the degree of polarization of the reflected light 10a tends to be considerably increased by setting the repetition pitch d3 between the prism portion 11a and the divided portion 11b to be small. And it is thought that the tendency becomes remarkable by setting the repetition pitch d3 to be smaller than the wavelength of the incident light (visible light) 10 or less.
- the repetition pitch d3 0.4 ⁇ m
- the above ratio is practically sufficiently large as about 100, and even if the repetition pitch d3 is smaller than 0.2 ⁇ m, it is only difficult to form the dividing prism 11. Therefore, it is practical to set the repetition pitch d3 to 0.2 ⁇ m or more.
- the width d1 of the prism portion 11a is set to 0.4 ⁇ m
- the width d2 of the divided portion 11b is set to 0.4 ⁇ m
- the repetition pitch d3 thereof is set to 0.8 ⁇ m.
- the reflection angle of the reflected light 10a changes to 80 degrees when the incident angle of the incident light 10 is 20 degrees, and changes to 90 degrees when the incident angle of the incident light 10 is 10 degrees.
- the ratio of the relative luminous intensity of the reflected light 10a in the case of parallel polarization to that in the case of polarized light is twice or more in any case.
- the width d1 of the prism portion 11a is set to 0.4 ⁇ m
- the width d2 of the divided portion 11b is set to 0.4 ⁇ m
- the repetition pitch d3 thereof is set to 0.8 ⁇ m.
- the reflection angle of the reflected light 10a varies as 130 degrees, 120 degrees, and 100 degrees, but the ratio of the relative luminous intensity of the reflected light 10a in the case of the parallel polarized light to the case of the vertically polarized light is 2 in any case. It is more than double.
- the dividing prism 11 has the prism portion 11a and the dividing portion 11b having the same width as the light wavelengths of the light sources 5a and 5b, respectively. Since the prism portions 11a and the divided portions 11b are alternately and repeatedly formed along the direction parallel to the end faces facing the light sources 5a and 5b, the reflected light 10a reflected by the divided prism 11 is converted into the divided prism 11. It is possible to make light that contains more parallel polarized light having electric field vibration direction in the direction parallel to the ridge line direction of the split prism 11 than vertical polarized light having electric field vibration direction in the direction perpendicular to the ridge line direction (that is, reflected light).
- the 10a can be converted into light having a high degree of polarization). As a result, the light utilization efficiency can be improved without using a reflective polarizing plate and without performing multiple reflection. Further, since the diffraction phenomenon is not used, color breakup can be prevented.
- the prism portion 11a of the dividing prism 11 is a recess formed in the back surface of the light guide plate 3, there is no risk of damage due to contact between other members and the light guide plate, and the light guide plate 3 has a stable structure.
- a dividing prism 11 can be provided inside.
- the split prism 11 is an isosceles triangular prism, and the base side of the isosceles triangle is disposed on the back surface of the light guide plate 3, and the prism portion 11a and the split portion 11b are arranged in the ridge line direction of the apex angle of the isosceles triangle.
- the splitting prism 11 is formed symmetrically with respect to the end faces on both sides of the light guide plate 3, so that light coming from either end face on both sides of the light guide plate 3 is effective. It can be reflected to the front side of the light guide plate 3 as light having a high degree of polarization.
- the width of each of the prism portion 11a and the divided portion 11b of the dividing prism 11 is 0.8 ⁇ m or less, and therefore effective when the light from the light source is visible light.
- the effect of the dividing prism 11 can be obtained.
- the length d0 in the repeating direction of the prism portion 11a and the divided portion 11b in the divided prism 11 is 1 ⁇ m to 50 ⁇ m, there is no problem of light scattering due to diffraction, and the effect of the divided prism 11 can be obtained.
- Embodiment 2 a split prism mold for forming the split prism 11 of the first embodiment and a manufacturing method thereof will be described.
- FIGS. 10 and 11 are diagrams showing the configuration of the dividing prism mold 15, FIG. 10 is a perspective view of the dividing prism mold 15, and FIG. 11 is a cross-sectional view taken along the line XI-XI shown in FIG. It is.
- the divided prism mold 15 includes a prism partial mold portion 15 b that forms the prism portion 11 a of the divided prism 11 on the bottom mold portion 15 a that forms the bottom surface of the light guide plate 3. Is formed by forming a plurality of protrusions vertically and horizontally.
- a mold (not shown) for forming the upper and side surfaces of the light guide plate 3 is combined with a split prism mold 15, and a molten transparent resin is injected into the combined mold and cured.
- the light guide plate 3 is formed of a transparent resin
- the dividing prism 11 is formed as a recess on the back surface of the light guide plate 3.
- the divided prism 11 is pressed against the back surface of the light guide plate 3 made of transparent resin by pressing the heated split prism mold 15 against the back surface of the light guide plate 3 made of thermoplastic transparent resin. It is formed as a recess.
- an ultraviolet effect resin film is applied to the back surface of the light guide plate 3 formed of a transparent resin, and the concave and convex portions of the prism part mold portion 15b of the split prism mold 15 are pressed and transferred.
- the dividing prism 11 is formed as a recess on the back surface of the light guide plate 3.
- a transparent film obtained by applying a UV effect resin film on the surface of the transparent film, pressing and transferring the unevenness of the prism part mold portion 15b of the split prism mold 15, and then curing the UV curable resin with UV rays can be obtained.
- the dividing prism 11 is formed as a concave portion by being attached to the back surface of the light guide plate 3.
- ⁇ Description of Manufacturing Method of Dividing Prism Mold 15> First, as shown in FIG. 12 (a), for example, using a quartz substrate mold in which line and space is formed, a plurality of ridges 15c are linearly parallel to each other on the bottom mold part 15a by electroforming. In addition, a basic die 15K formed in a line-and-space shape is formed at a predetermined interval from each other.
- the above quartz substrate mold is formed by forming the concave / convex pattern of the basic mold 15K on the surface of the quartz substrate using, for example, an exposure technique, and forming a conductive film on the surface.
- Each ridge portion 15c is a portion finally formed in each prism partial mold portion 15b.
- a protective agent 17 is applied and cured on the basic mold 15K so as to cover the plurality of ridges 15c.
- each recess 15e has an inverted triangular cross section or an inverted trapezoidal cross section, and is formed so as to extend linearly in a direction perpendicular to the convex strip 15c at a depth reaching the surface of the bottom mold 15a.
- line part 15c is formed in the saw shape in which the isosceles triangle was located in a line in a row, and each of these isosceles triangle becomes the prism formation metal mold
- the protective agent 17 is removed.
- the split prism mold 15 is formed from the basic mold 15K.
- the divided prism mold 15 is manufactured by electroforming and cutting, so that the divided prism mold 15 is manufactured at low cost using a known technique. it can.
- the depth of the groove 15e is shallower than the protrusion 15c.
- Embodiment 3 FIG.
- the planar light source device 1B is a modification of the first embodiment, and is disposed to face the light guide plate 3 and one end face (light incident surface) of the light guide plate 3 as shown in FIG.
- a phase difference plate 21 disposed on the side surface (reflection surface), a reflection plate 23 disposed opposite to the reflection surface of the light guide plate 3 via the phase difference plate 21, and a light exit surface of the light guide plate 3.
- And an inverted prism sheet 25 disposed so as to face each other with the phase difference plate 7 interposed therebetween.
- a liquid crystal panel 13 of the liquid crystal display device is disposed in front of the light exit surface of the light guide plate 3.
- the light guide plate 3 is formed, for example, in the shape of a rectangular plate by a transparent member such as a transparent resin, and one or more divided prisms 11 are formed on the inner back surface. ing.
- the split prism 11 is formed in the same manner except that the apex angle of the isosceles triangle is set to an obtuse angle of 160 degrees to 175 degrees (here, 170 degrees). Is done.
- the height d10 of the dividing prism 11 is set to 0.22 ⁇ m, for example.
- the phase difference plate 7 has a slow axis attached to the light incident surface of the light guide plate 3 at an angle of 45 degrees, and is incident on the divided reflection prism 11 at an angle of about 50 to 60 degrees obliquely. On the other hand, it has the function of a (1/2) wave plate.
- the phase difference plate 7 transmits light incident on and transmitted through the phase difference plate 7 with its polarization direction rotated by 90 degrees.
- the retardation plate 21 is a (1/4) wave plate whose slow axis is inclined 45 degrees with respect to the normal direction of the light emitting surface of the light guide plate 3.
- the phase difference plate 21 converts linearly polarized light (circularly polarized light) transmitted through the phase difference plate 21 into circularly polarized light (linearly polarized light) and transmits the light.
- the reverse prism sheet 25 is configured by forming a plurality of prisms 25b on the back surface (surface on the light guide plate 3 side) of a sheet portion 25a formed into a sheet shape by a transparent member.
- the plurality of prisms 25b extend in parallel to the light incident surface of the light guide plate 3 and are formed at predetermined pitch intervals.
- each prism 25b is formed in an isosceles triangular prism shape, for example, and the base side surface of the isosceles triangle is disposed on the back surface of the sheet portion 25a (therefore, the apex side of the isosceles triangle is on the light guide plate 3 side).
- the ridgeline direction of the apex angle of the isosceles triangle is arranged so as to be parallel to the light incident surface of the light guide plate 3.
- this flat light source device 1B As shown in FIG. 13, when the light source 5a is turned on, the light 10 from the light source 5a enters the light guide plate 3 from the light incident surface of the light guide plate 3, and the inner surface of the light guide plate 3 Then, the light is propagated while being reflected, and is incident on the prism surface of the dividing prism 11 at a certain point, and is separated into reflected light 10a reflected by the prism surface and transmitted light 10b transmitted through the prism surface.
- the reflected light 10a is caused by vertical polarized light having the direction of vibration of the electric field in the direction perpendicular to the ridge line direction of the divided prism 11 due to the presence of the divided portion 11b of the divided prism 11.
- the light includes a considerably larger amount of horizontally polarized light having the direction of vibration of the electric field in the direction parallel to the ridge line direction of the dividing prism 11.
- the reflected light 10a exits from the light exit surface of the light guide plate 3 and passes through the phase difference plate 7 so that the polarization direction is rotated by 90 degrees (therefore, the vertically polarized light is equivalent to the parallel polarized light.
- the light is transmitted to the reverse prism sheet 25 and refracted in the front direction of the light exit surface of the light guide plate 3 to irradiate the liquid crystal panel 13.
- FIG. 15 is a diagram showing the reflectivity of the reflected light 10a by the split prism 11 at the interface between the inside of the light guide plate 3 and the outside (air layer).
- the parallel polarized light has a higher reflectance than the vertically polarized light at the interface between the inside and the outside ( That is, the vertically polarized light is easier to transmit than the parallel polarized light).
- the reflected light 10a reflected by the splitting prism 11 contains a larger amount of horizontally polarized light than vertically polarized light. Therefore, as described above, the polarization direction of the reflected light is rotated 90 degrees by the phase difference plate 7 and parallel. By converting the light into a light that includes much more vertically polarized light than polarized light, the transmittance of the reflected light 10a from the inside of the light guide plate 3 to the outside is improved.
- the apex angle of the split prism 11 is an obtuse angle (therefore, the prism surface 10c is a gentle slope)
- the light exit surface (that is, the phase difference plate 7) of the reflected light 10a reflected by the prism surface 10c. ) Is relatively large. For example, as shown in FIG. 14, when the incident angle of the incident light 10 is 45 degrees, the incident light 10 is reflected once by the light exit surface of the light guide plate 3, then reflected by the dividing prism 11, and again of the light guide plate 3. When incident on the light exit surface, the incident angle is 35 degrees.
- the angle at which the reflected light 10a is emitted from the light guide plate 3 to the outside is also relatively large (that is, the reflected light 10 is difficult to be emitted in the front direction of the light emission surface of the light guide plate 3). Therefore, as shown in FIG. 13, the reflected light 10 a emitted from the light guide plate 3 is refracted by the inverted prism sheet 25 and emitted in the front direction of the light emission surface of the light guide plate 3.
- the transmitted light 10b passes through the dividing prism 11, propagates again while being reflected by the inner surface of the light guide plate 3 and the reflection sheet 9, and passes through the other end surface of the light guide plate 3 and the phase difference plate 21 to be reflected by the reflection plate. It is reflected by 23 and propagates in the light guide plate 3 again. At that time, the transmitted light 10b changes its polarization state due to the birefringence of the phase difference plate 21 and the light guide plate 3, and increases the parallel polarization again.
- the transmitted light 10b reflected by the reflecting plate 23 propagates in the same manner as the incident light 10 because the split prism 11 is an isosceles triangle. Accordingly, the transmitted light 10b is also effectively emitted from the light exit surface of the light guide plate 3.
- planar light source device 1B similarly to the first embodiment, light with a high degree of polarization (light with a considerably high proportion of light in a specific polarization state) is emitted.
- the phase difference plate 7 that rotates the polarization direction of the light emitted from the front surface of the light guide plate 3 by 90 degrees is disposed on the front surface of the light guide plate 3. Therefore, the outgoing light emitted from the front surface (ie, the inside) of the light guide plate 3 to the outside (ie, the air layer) is a splitting prism rather than a parallel polarized light having a direction of vibration of an electric field in a direction parallel to the ridge line direction of the splitting prism 11.
- the light that contains more of the vertically polarized light having the vibration direction of the electric field in the direction perpendicular to the ridgeline direction of the eleventh line can be obtained. Can be improved.
- the apex angle of the dividing prism 11 is an obtuse angle of 160 to 175 degrees
- the height d10 of the dividing prism 11 can be made lower (that is, shallower) than the total length d0 of the dividing prism, and the mold 15 for the dividing prism can be manufactured.
- the split prism 11 can be easily formed on the light guide plate 3.
- the front surface side of the light guide plate 3 has a plurality of prisms extending in a direction parallel to the end surface (light incident surface) of the light guide plate 3 facing the light source 5a on the light guide plate 3 side surface. 3 is arranged so that the light emitted from the front surface of the light guide plate 3 is refracted in the front direction of the front surface of the light guide plate 3. The light can be propagated in the front direction of the front surface of the light guide plate 3.
- the (1 ⁇ 4) wavelength plate 21 and the reflection plate 23 are disposed in order on the other end face (the surface opposite to the light incident surface) of the light guide plate 3, the (1 ⁇ 4) wavelength plate 21 and the reflection are provided.
- the plate 23 can reflect the light of the light source 15a that has reached the other end face of the light guide plate 3 by converting it into light containing a large amount of parallel polarized light, thereby improving the light reusability.
- FIG. 16 is a schematic configuration diagram of a planar light source device 1C according to Embodiment 4, showing a plan view of the planar light source device 1C and a side view on the right side thereof.
- the planar light source device 1 ⁇ / b> C includes the light guide plate 3, the light source light guide plate 30 disposed to face at least one end surface (light incident surface) of the light guide plate 3, and one end surface of the light source light guide plate 30.
- a point light source 50a disposed on the (light incident surface).
- the light source light guide plate 30 functions to refract the light 100 from the point light source 50 a and make it incident on the light incident surface of the light guide plate 3.
- the light source light guide plate 30 of the present embodiment has the same configuration as the light guide plate 3 of the third embodiment. That is, the light source light guide plate 30 includes a phase difference plate 70 disposed on the front surface (light emission surface) of the light source light guide plate 30, a reflection sheet 90 disposed on the back surface of the light source light guide plate 30, and the light source light guide plate 30. A phase difference plate 210 disposed on a side surface (reflection surface) opposite to the light incident surface side, and a reflection plate 230 disposed opposite to the reflection surface of the light source light guide plate 30 via the phase difference plate 210; The light source light guide plate 30 includes a reverse prism sheet 250 disposed on the light emission surface of the light source light guide plate 30 so as to face the light exit surface.
- the light source light guide plate 30 has the same configuration as the light guide plate 3 of the third embodiment is shown, but the light source light guide plate 30 has the same configuration as the light guide plate 3 of the first embodiment. May be used.
- the liquid crystal panel 13 (not shown) of the liquid crystal display device is disposed in front of the light exit surface of the light guide plate 3.
- a reflection prism 31 extending in a direction parallel to the light exit surface of the light source light guide plate 30 and the light entrance surface of the light guide plate 3 is formed on the surface of the light guide plate 3 opposite to the light exit surface.
- the light source light guide plate 30 is formed, for example, in a rectangular plate shape by a transparent member such as a transparent resin, and the inner back surface (opposite to the surface facing the light guide plate 3).
- a transparent member such as a transparent resin
- the inner back surface opposite to the surface facing the light guide plate 3
- One or more dividing prisms 110 are formed on the surface).
- the dividing prism 110 is formed in the same manner with an apex angle of an isosceles triangle having an obtuse angle of 160 degrees to 175 degrees (here, 170 degrees), and the height d10 of the dividing prism 110 is For example, it is set to 0.22 ⁇ m.
- the retardation plate 70 has a slow axis attached to the light incident surface of the light source light guide plate 30 at an angle of 45 degrees, and is incident at an angle of about 50 to 60 degrees obliquely from the divided reflection prism 110. It has the function of a (1/2) wavelength plate for the light to be transmitted.
- the phase difference plate 70 transmits light incident on and transmitted through the phase difference plate 70 with its polarization direction rotated by 90 degrees.
- the phase difference plate 210 is a (1 ⁇ 4) wavelength plate whose slow axis is inclined by 45 degrees with respect to the normal direction of the light emitting surface of the light source light guide plate 30.
- the phase difference plate 210 converts linearly polarized light (circularly polarized light) transmitted through the phase difference plate 210 into circularly polarized light (linearly polarized light) and transmits the light.
- the reverse prism sheet 250 is configured by forming a plurality of prisms 250b having apex angles of about 60 degrees on the back surface (surface on the light source light guide plate 30 side) of a sheet portion 250a formed in a sheet shape by a transparent member.
- the plurality of prisms 250b are formed so as to extend in parallel to the light incident surface of the light source light guide plate 30 and to be spaced apart from each other by a predetermined pitch.
- each prism 250b is formed in an isosceles triangular prism shape, for example, and the base side surface of the isosceles triangle is disposed on the back surface of the sheet portion 250a (therefore, the apex side of the isosceles triangle is the light source light guide plate 30.
- the ridge line direction of the apex angle of the isosceles triangle is arranged so as to be parallel to the light incident surface of the light source light guide plate 30.
- the point light source 50a when the point light source 50a is turned on as shown in FIG. 16, the light 100 from the point light source 50a enters the light source light guide plate 30 from the light incident surface of the light source light guide plate 30, and the light source The light propagates while being reflected by the inner surface of the light guide plate 30, and enters a prism surface of the split prism 110 at a certain point, and is separated into reflected light 100 a reflected by the prism surface and transmitted light 100 b transmitted through the prism surface. To do.
- the reflected light 100a is more than the vertically polarized light having the vibration direction of the electric field in the direction perpendicular to the ridge line direction of the split prism 110.
- the light includes a considerable amount of horizontally polarized light having the direction of vibration of the electric field in a direction parallel to the ridge line direction of the dividing prism 110.
- the reflected light 100a exits from the light exit surface of the light source light guide plate 30 and passes through the phase difference plate 70 so that the polarization direction is rotated by 90 degrees (so that the vertically polarized light is more than the parallel polarized light.
- the light is transmitted to the reverse prism sheet 250, is refracted in the front direction of the light exit surface of the light source light guide plate 30, and enters the light guide plate 3. Further, the light 100 c incident on the light guide plate 3 propagates through the light guide plate 3, is reflected by the reflecting prism 31, is emitted from the light radiation of the light guide plate 3, and irradiates the liquid crystal panel 13.
- the reflectance of the reflected light 100a at the interface between the inside and outside (air layer) of the light guide plate 3 has the characteristics shown in FIG. Therefore, when the reflected light 100a propagates from the inside of the light source light guide plate 30 to the outside (air layer), the parallel polarized light has higher reflectance than the vertically polarized light at the interface between the inside and the outside (that is, more than the parallel polarized light). Is also easier to transmit vertically polarized light). Since the reflected light 100a reflected by the split prism 110 includes a larger amount of horizontally polarized light than vertically polarized light, as described above, the polarization direction of the reflected light is rotated 90 degrees by the phase difference plate 70, and is parallel. By converting the light into a light that contains a larger amount of vertically polarized light than polarized light, the transmittance of the reflected light 100a from the inside of the light source light guide plate 30 to the outside is improved.
- the apex angle of the split prism 110 is an obtuse angle (therefore, the prism is a gentle slope)
- the reflected light 100a reflected by the prism surface is directed to the light exit surface (that is, the phase difference plate 70) of the light source light guide plate 30.
- the incident angle of becomes relatively large.
- the incident angle of the incident light 100 is 45 degrees
- the incident light 100 is reflected once by the light exit surface of the light source light guide plate 30 and then reflected by the dividing prism 11. Then, when the light enters the light exit surface of the light source light guide plate 30 again, the incident angle becomes 35 degrees.
- the angle at which the reflected light 100a is emitted from the light source light guide plate 30 to the outside is also relatively large (that is, the reflected light 100a is not easily emitted in the front direction of the light exit surface of the light source light guide plate 30). Therefore, the reflected light 100a emitted from the light source light guide plate 30 is refracted by the inverted prism sheet 250 and emitted with high directivity in the front direction of the light emission surface of the light source light guide plate 30.
- the transmitted light 100b passes through the dividing prism 110, propagates again while being reflected by the inner surface of the light source light guide plate 30 and the reflection sheet 90, and passes through the other end surface of the light source light guide plate 30 and the phase difference plate 210.
- the light is reflected by the reflection plate 230 and propagates in the light source light guide plate 30 again.
- the transmitted light 100b changes its polarization state due to the birefringence of the phase difference plate 210 and the light source light guide plate 30, and increases the parallel polarization again.
- the transmitted light 100b reflected by the reflecting plate 230 propagates in the same manner as the incident light 100 because the split prism 110 is an isosceles triangle. Thus, the transmitted light 100b is also effectively emitted from the light exit surface of the light source light guide plate 30.
- the reflected light 100a that has passed through the reverse prism sheet 250 is radiated with high directivity mainly in the front direction of the light source light guide plate 30 (the direction toward the light guide plate 3), and more vertically polarized light than parallel polarized light.
- the light is incident on the light guide plate 3 in a state where it contains a considerable amount of the light.
- the light 100 c incident on the light guide plate 3 propagates through the light guide plate 3, is reflected by the reflecting prism 31 in the light guide plate 3, is emitted from the light exit surface of the light guide plate 3, and irradiates the liquid crystal panel 13.
- the normal direction of the reflection surface of the reflection prism 31 is in the plane of the reflection optical path of the incident light 100c, the component ratio of the polarization is preserved when the incident light 100c is reflected by the reflection prism 31. Therefore, the light that irradiates the liquid crystal panel 13 includes considerably more vertically polarized light than parallel polarized light.
- light with a high degree of polarization (light with a considerably high proportion of light in a specific polarization state) is emitted from the light guide plate 3.
- the directivity of the emitted light is high in the front direction of the light guide plate 3.
- a phase difference plate 70 that rotates the polarization direction of light emitted from the front surface of the light source light guide plate 30 by 90 degrees is disposed on the front surface of the light source light guide plate 30.
- the light emitted from the front surface (inside) of the light source light guide plate 30 to the outside (air layer) of the split prism 110 is more than the parallel polarized light having the direction of vibration of the electric field in the direction parallel to the ridge line direction of the split prism 110
- Light that includes more vertically polarized light having the direction of vibration of the electric field in the direction perpendicular to the ridge direction can be obtained.
- permeability of the light in the interface of the inside of the light source light-guide plate 30 and the exterior (air layer) can be improved.
- an end face (light incident surface) of the light source light guide plate 30 facing the point light source 50a is provided on the surface on the light source light guide plate 30 side.
- an inverted prism sheet that refracts the light emitted from the front surface (light exit surface) of the light source light guide plate 30 in the front direction of the front surface of the light source light guide plate 30 is disposed. Therefore, even when the light emitted from the front surface of the light source light guide plate 30 is warped left and right, it can be propagated in the front direction of the front surface of the light source light guide plate 30.
- wavelength plate 210 and reflecting plate 230 are arranged in order on the end surface of the other side (surface opposite to the light incident surface) of the light source light guide plate 30.
- the light of the light source 150a that has reached the other end face of the light source light guide plate 30 can be converted into light containing a large amount of parallel polarized light and reflected. Can be improved.
- the reflection prism 31 of the light guide plate 3 is formed in a direction parallel to the exit surface of the light source light guide plate 30 and the light incident surface of the light guide plate 3, the normal direction of the reflection surface is the reflection light path of the incident light 100c. In the plane. Therefore, when the incident light 100c is reflected by the reflecting prism 31, the polarization component ratio is preserved. Therefore, the light that irradiates the liquid crystal panel 13 includes considerably more vertically polarized light than parallel polarized light. By adjusting the angle of the transmission axis of the polarizing plate provided on the flat light source device side of the liquid crystal panel to the angle of the electric field vibration direction of the vertically polarized light, a highly efficient and bright display can be realized. In addition, since the directivity of light incident on the liquid crystal panel is not disturbed, high luminance can be realized with respect to the front direction of the liquid crystal panel.
- the light source light guide plate 30 may have the same configuration as the light guide plate 3 of the first embodiment, and in that case, the same effect can be obtained.
- planar light source device As described above, the planar light source device according to the present invention has been described by taking the backlight of the liquid crystal display as an example, but the application of the present invention is not limited to this.
- the planar light source device of the present invention can be used as a planar light source for any device that uses polarized light, such as a front light of a reflective liquid crystal display, for example, and when used in such a manner, the effect of improving luminance efficiency can be obtained. Is clear.
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Abstract
Description
<全体構成>
この実施の形態に係る平面光源装置1は、例えば液晶表示装置のバックライト装置として使用可能であり、その構成を図1~図4に示す。図1は当該平面光源装置1の斜視図であり、図2は側面図、図3は平面視図、図4は図1に示すIV-IV線に沿った断面図である。
図5は、分断プリズム11の反射シミュレーションで使用した導光板3のモデルを示したものである。
以上の様に構成された平面光源装置1によれば、分断プリズム11は、それぞれ光源5a,5bの光の波長と同程度の幅のプリズム部分11aと分断部分11bとを有し、導光板3における光源5a,5bに対向する端面に平行な方向に沿って、プリズム部分11aと分断部分11bとを交互に繰り返して形成されるので、分断プリズム11で反射された反射光10aを、分断プリズム11の稜線方向に垂直な方向に電界の振動方向を持つ垂直偏光よりも分断プリズム11の稜線方向に平行な方向に電界の振動方向を持つ平行偏光の方を多く含む光にできる(即ち、反射光10aを偏光度の高い光にできる)。これにより、反射偏光板を用いず且つ多重反射を行わずに光の利用効率を向上できる。また回折現象を利用しないので、色割れも防止できる。
この実施の形態では、実施の形態1の分断プリズム11を形成するための分断プリズム用金型およびその製造方法を説明する。
図10および図11は、分断プリズム用金型15の構成を示す図であり、図10は当該分断プリズム用金型15の斜視図、図11は図10に示すXI-XIに沿った断面図である。図10および図11の様に、この分断プリズム用金型15は、導光板3の底面を形成する底面金型部15a上に、分断プリズム11のプリズム部分11aを形成するプリズム部分金型部15bが縦横に複数突形成されて構成される。
まず図12(a)の様に、例えばラインアンドスペースを形成した石英基板金型を用い、電鋳法により底面金型部15a上に、複数の凸条部15cが、互いに平行な直線状で且つ互いに所定間隔空けてラインアンドスペース状に形成された基本金型15Kを形成する。尚、上記の石英基板金型は、石英基板の表面に例えば露光技術を用いて基本金型15Kの凹凸パターンを形成し、その表面に導電膜を成膜して形成したものである。
この実施の形態に係る平面光源装置1Bは、実施の形態1の変形例であり、図13の様に、導光板3と、導光板3の一方の端面(光入射面)に対向配置された光源5aと、導光板3の前面(光射出面)に配設された位相差板7と、導光板3の裏面に配置された反射シート9と、導光板3の前記光入射面側と反対側の側面(反射面)に配設された位相差板21と、導光板3の前記反射面に位相差板21を介して対向配置された反射板23と、導光板3の光射出面に位相差板7を介して対向配置された逆プリズムシート25とを備える。尚、導光板3の光射出面の前方に、液晶表示装置の液晶パネル13が配置される。
図16は、実施の形態4に係る平面光源装置1Cの構成概略図であり、平面光源装置1Cの平面図とその右側に側面図を示している。図16の様に、当該平面光源装置1Cは、導光板3と、導光板3の少なくとも一方の端面(光入射面)に対向配置された光源導光板30と、光源導光板30の一方の端面(光入射面)に配置された点光源50aとを備える。光源導光板30は、点光源50aからの光100を屈折させ、導光板3の光入射面に入射させるよう機能する。
Claims (11)
- 平板状の導光板(3)と、
前記導光板(3)の両側の端面の少なくとも一方に対向配置された光源(5a)と、
前記導光板(3)の内部における裏面に形成され、前記光源(5a)から前記導光板(3)に入射された光を前記導光板(3)の前面側に反射させる分断プリズム(11)と、
を備え、
前記分断プリズム(11)は、それぞれ前記光源(5a)の光の波長と同程度以下の幅のプリズム部分(11a)と分断部分(11b)とを有し、前記導光板(3)における前記光源(5a)に対向する前記端面に平行な方向に沿って、前記プリズム部分(11a)と前記分断部分(11b)とを交互に繰り返して形成されることを特徴とする平面光源装置。 - 分断プリズム(11)の前記プリズム部分(11a)は、前記導光板(3)の裏面に凹設された凹部であることを特徴とする請求項1に記載の平面光源装置。
- 前記導光板(3)の前面には、前記導光板(3)の前面から射出された光の偏光方向を回転させる位相差板(7)が配設されることを特徴とする請求項1に記載の平面光源装置。
- 前記分断プリズム(11)は、2等辺三角柱プリズムにおいて、その2等辺三角の底辺側の面を前記導光板(3)の裏面上に配置し、その2等辺三角の頂角の稜線方向に前記プリズム部分(11a)と前記分断部分(11b)とを交互に繰り返したものであることを特徴とする請求項1に記載の平面光源装置。
- 前記分断プリズム(11)の前記頂角は、160度~175度の鈍角であることを特徴とする請求項4に記載の平面光源装置。
- 前記導光板(3)の前面側には、前記導光板(3)側の面に、前記導光板(3)における前記光源(5a)に対向する前記端面に平行な方向に延びた複数のプリズム(25b)を有し、前記導光板(3)の前面から射出された光を前記導光板(3)の前面の正面方向に屈折させる逆プリズムシート(25)が配置されることを特徴とする請求項1に記載の平面光源装置。
- 前記導光板(3)の一方側の端面だけに前記光源(5a)が対向配置される場合において、
前記導光板(3)の他方側の端面には、順に(1/4)波長板(21)および反射板(23)が配設されることを特徴とする請求項1に記載の平面光源装置。 - 前記光源(5a)の光が可視光の場合は、前記分断プリズム(11)の前記プリズム部分(11a)および前記分断部分(11b)の各々の幅は、0.8μm以下であることを特徴とする請求項1に記載の平面光源装置。
- 前記分断プリズム(11)における前記プリズム部分(11a)と前記分断部分(11b)との繰り返し方向の長さは、1μm~50μmであることを特徴とする請求項1に記載の平面光源装置。
- 底面金型部上に、2等辺三角柱状の分断プリズムのプリズム部分を形成するプリズム部分金型部(15b)が縦横に複数突形成された分断プリズム用金型の製造方法であって、
電鋳法により、底面金型部(15a)上に、複数の凸条部(15c)が、互いに平行な直線状で且つ互いに所定間隔空けて形成された基本金型を形成する工程と、
前記基本金型上に、前記複数の凸条部(15c)を被覆する様に保護剤(17)を塗布し硬化させる工程と、
切削加工により、前記基本金型上に塗布された前記保護剤(17)の表面に、断面逆三角形状または断面逆台形状の複数の凹条部(15e)を、前記底面金型部(15a)の表面付近に達する深さで、前記凸条部(15c)と直交する方向に直線状に延びる様に凹設し、前記凸条部(15c)から前記プリズム部分金型部(15b)を形成する工程と、
前記保護剤(17)を除去する工程と、
を備えることを特徴とする分断プリズム用金型の製造方法。 - 平板状の導光板(3)と、
前記導光板(3)の両側の端面の少なくとも一方に対向配置された光源導光板(30)と、
前記光源導光板(30)の少なくとも一方の端面に対向配置された光源(50a)と、
前記導光板(3)の内部における裏面に形成され、光源導光板(30)に平行な方向に伸びる反射プリズム(31)と、
前記光源導光板(30)の内部における前記導光板(3)に対向する面と反対の面に形成され、前記光源(50a)から前記光源導光板(30)に入射された光を前記導光板(3)に対向する面側に反射させる分断プリズム(110)と、
を備え、
前記分断プリズム(110)は、それぞれ前記光源(50a)の光の波長と同程度以下の幅のプリズム部分(11a)と分断部分(11b)とを有し、前記導光板(3)における前記光源(50a)に対向する前記端面に平行な方向に沿って、前記プリズム部分(11a)と前記分断部分(11b)とを交互に繰り返して形成されることを特徴とする平面光源装置。
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US12/919,382 US8348490B2 (en) | 2008-02-25 | 2009-02-19 | Planar light source device and method of manufacturing divided prism mold |
JP2010500660A JP5005086B2 (ja) | 2008-02-25 | 2009-02-19 | 平面光源装置 |
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US8348490B2 (en) | 2013-01-08 |
JP5005086B2 (ja) | 2012-08-22 |
US20110002142A1 (en) | 2011-01-06 |
JPWO2009107533A1 (ja) | 2011-06-30 |
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