JP2012004038A - Surface light source device, planar light generation plate, and transmission type image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface light source device capable of emitting light from a point light source as planar light of more uniform luminance, a planar light generation plate, and a transmission type image display device.SOLUTION: The surface light source device 10 includes a plurality of point light sources 12 and a planar light generation plate 14 which guides and emits light from the plurality of point light sources. The planar light generation plate 14 has a plate body 18 which has a rear face 18b which is located on the plurality of point light sources 12 side and a front face 18a which is located on the opposite side to the rear face and from which the light is emitted and a reflection part 24 which is installed on the rear face and reflects a part of light propagating in the plate body to the front face side. Then, in the rear face 18b, a plurality of recessed portions which are a plurality of recessed portions 22 corresponding to the plurality of point light sources 12 and from which the light from the corresponding point light sources enters, are formed. In this structure, the light propagating in the plate body 18 is diffused by the reflection part and emitted from the front face side, thereby, the surface light source device 10 can emit light from the point light source 12 as planar light having more uniform luminance on the surface.

Description

  The present invention relates to a surface light source device, a planar light generating plate, and a transmissive image display device.

  Some backlight units (surface light source devices) included in a transmissive image display device such as a liquid crystal display device employ a point light source such as a light emitting diode. An example of such a backlight unit is described in Patent Document 1. The backlight unit described in Patent Literature 1 includes a plurality of light guide plates and a plurality of point light sources. Each light guide plate has a side surface and an output surface, the plurality of light guide plates are arranged with the side surfaces facing each other, and the point light source is configured to simultaneously enter light into the plurality of light guide plates. The light guide plate is disposed on each side surface. In the technique described in Patent Document 1, since light from each point light source is incident from the side surface of the corresponding light guide plate and is emitted from the emission surface, light from a plurality of point light sources can be emitted as planar light. It has become.

JP 2009-272251 A

  As described above, in the technique described in Patent Document 1, light from a point light source can be emitted as planar light with a configuration in which a plurality of light guide plates are arranged on the point light source. In a surface light source device used as a backlight unit of an image display device, uniformity of luminance of emitted light is desired.

  Accordingly, an object of the present invention is to provide a surface light source device, a planar light generating plate, and a transmissive image display device that can emit light from a point light source as planar light with more uniform luminance.

  A surface light source device according to the present invention includes a plurality of point light sources and a surface light generation plate that emits light from the plurality of point light sources as surface light. A plate body having a back surface located on the point light source side, a surface located on the opposite side of the back surface from which light is emitted, and at least part of the light that is provided on the back surface and propagates in the plate body And a plurality of recesses corresponding to the plurality of point light sources, where the light from the corresponding point light sources is incident, is formed on the back surface. ing.

  In this configuration, since the light from the point light source is incident on the plate body through the concave portion, the light from the point light source can be dispersed and incident as compared with the case where the concave portion is not formed on the back surface. Further, since the reflecting portion is provided on the back surface side, the light propagating in the plate body is reflected on the back surface side by reflection different from the total reflection condition. Since the light reflected in this way is emitted from the surface side of the plate main body, the light can be diffused and emitted by the reflecting portion. Therefore, in the said structure, light can be radiate | emitted from the whole surface of a board main body as planar light with a more uniform brightness | luminance.

  In the surface light source device according to the present invention, it is preferable that the reflecting section includes a plurality of first reflecting dots that reflect at least a part of the light. In this case, it is possible to easily equalize the luminance depending on the arrangement state of the first reflective dots.

  In the surface light source device according to the present invention, it is preferable that the planar light generating plate further includes a light diffusion layer that is laminated on the surface of the plate body and diffuses light emitted from the surface. Since the light emitted from the surface of the plate body is emitted after being diffused by the light diffusion layer, the luminance of the planar light can be made more uniform.

  In the surface light source device according to the present invention, it is preferable that the planar light generation plate further includes a light amount adjustment unit that adjusts the amount of light emitted from the surface of the plate body. In this configuration, the luminance can be further uniformed by adjusting the amount of light emitted from the surface by the light amount adjustment unit.

  In the surface light source device according to the present invention, it is preferable that the light amount adjustment unit has a plurality of second reflection dots that reflect at least a part of the light. In this case, it is possible to easily make the luminance uniform depending on the arrangement state of the second reflective dots.

  The planar light generating plate according to the present invention includes a plate body having a surface from which light is emitted and a back surface located on the opposite side of the front surface, and at least a part of light that is provided on the back surface and propagates in the plate body. And a plurality of recesses are formed on the back surface.

  In this configuration, when a planar light generating plate is arranged on a plurality of point light sources arranged corresponding to each recess, light from each point light source is incident on the plate body through the recess. Therefore, in the planar light generating plate, light from the point light source can be dispersed and incident as compared with the case where no recess is formed on the back surface. Further, since the reflecting portion is provided on the back surface side, the light propagating in the plate body is reflected on the back surface side by reflection different from the total reflection condition. Since the light reflected in this way is emitted from the surface side of the plate main body, the light can be diffused and emitted by the reflecting portion. Therefore, the planar light generating plate having the above-described configuration can emit light from a plurality of point light sources as planar light having a substantially uniform luminance.

  In the planar light generating plate according to the present invention, it is preferable that the reflecting portion has a plurality of first reflecting dots that reflect at least a part of the light. In this case, it is possible to easily equalize the luminance depending on the arrangement state of the first reflective dots.

  It is preferable that the planar light generating plate according to the present invention further includes a light diffusion layer that is laminated on the surface of the plate body and diffuses light emitted from the surface. In this configuration, the light emitted from the surface of the plate body is diffused by the light diffusion layer, so that the luminance can be further uniformed.

  It is preferable that the planar light generating plate according to the present invention further includes a light amount adjusting unit that adjusts the amount of light emitted from the surface of the plate main body. In this configuration, the luminance can be further uniformed by adjusting the amount of light emitted from the surface by the light amount adjusting unit.

  In the planar light generation plate according to the present invention, it is preferable that the light amount adjustment unit has a plurality of second reflection dots that reflect at least a part of the light. In this case, it is possible to easily make the luminance uniform depending on the arrangement state of the second reflective dots.

  A transmissive image display device according to the present invention is provided on a plurality of point light sources, a planar light generation plate that emits light from the plurality of point light sources as planar light, and the planar light generation plate. A transmissive image display unit illuminated with planar light emitted from the planar light generation plate, the planar light generation plate comprising a back surface positioned on the plurality of point light sources, and a back surface A plate body having a surface on the opposite side and having a surface from which light is emitted, and a reflecting portion that is provided on the back surface and reflects at least part of the light propagating in the plate body to the surface side, A plurality of recesses corresponding to the plurality of point light sources and having light incident from the corresponding point light sources are formed on the back surface.

  In this configuration, since the light from the point light source is incident on the plate body through the concave portion, the light from the point light source can be dispersed and incident as compared with the case where the concave portion is not formed on the back surface. Furthermore, since the reflection part is provided on the back surface side, the light propagating in the plate body is reflected on the back surface side under a reflection condition different from the total reflection. Since the light reflected in this way is emitted from the surface side of the plate main body, the light can be diffused and emitted by the reflecting portion. Therefore, in the above configuration, the entire surface of the plate body can be emitted as planar light with a substantially uniform luminance, and the transmissive image display unit is illuminated with the planar light. As a result, a high-quality image with reduced luminance unevenness can be displayed.

  In the transmissive image display device according to the present invention, it is preferable to further include a light diffusion layer that is laminated on the surface of the plate body and diffuses light emitted from the surface. In this configuration, the light emitted from the surface of the plate body is diffused by the light diffusion layer, so that the luminance can be further uniformed.

  ADVANTAGE OF THE INVENTION According to this invention, the surface light source device which can radiate | emit the light from a point light source as planar light with a more uniform brightness | luminance, a planar light generation plate, and a transmissive image display apparatus can be provided.

It is drawing which shows typically the cross-sectional structure of one Embodiment of the surface light source device which concerns on this invention. It is drawing which shows the arrangement pattern of several recessed part. It is a perspective view which shows schematic structure of an example of the transmissive | pervious image display apparatus using the surface light source device shown in FIG. It is drawing which shows typically the cross-sectional structure of other embodiment of the surface light source device which concerns on this invention. It is drawing which shows the other example of the arrangement pattern of a several recessed part.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same reference numerals are given to the same elements, and duplicate descriptions are omitted. Further, the dimensional ratios in the drawings do not necessarily match those described.

  FIG. 1 is a drawing schematically showing a cross-sectional configuration of an embodiment of a surface light source device according to the present invention. The surface light source device 10 includes a plurality of point light sources 12 and a planar light generation plate 14. The surface light source device 10 is a backlight unit that can be applied to a backlight of a transmissive image display device such as a liquid crystal television. In the following description, as shown in FIG. 1, the thickness direction of the planar light generating plate 14 is referred to as the z direction, and the two directions orthogonal to the z direction and orthogonal to each other are referred to as the x direction and the y direction. Call it.

  An example of the point light source 12 is a light emitting diode. The plurality of point light sources 12 are discretely arranged on the reflection sheet 16.

  The planar light generating plate 14 includes a plate main body 18 and a light diffusion layer 20 laminated on the surface 18 a of the plate main body 18. The planar light generating plate 14 is a surface emitting plate that emits light from the point light source 12 disposed on the back side of the planar light generating plate 14 in FIG. 1 as planar light (planar light). An example of the thickness of the planar light generating plate 14 is 2 mm or more and 30 mm or less.

  The example of the shape seen from the surface 18a side of the board main body 18 is a rectangle or a square. An example of the thickness of the plate body 18 is 1 mm to 10 mm. The plate body 18 is made of a transparent material. Examples of the refractive index of the transparent material are 1.4 to 1.65. An example of the transparent material is a transparent resin. Examples of the transparent resin are acrylic resin (refractive index: 1.49), polycarbonate resin (refractive index: 1.59), MS resin (methyl methacrylate-styrene copolymer resin) (refractive index: 1.56). ˜1.59), polystyrene resin (refractive index: 1.59), and the like. The plate main body 18 is usually used without adding a light diffusing agent as an additive, but may be added with a light diffusing agent as long as it is a slight amount that does not impair the object of the present invention.

  A plurality of recesses 22 are formed on the back surface 18 b of the plate body 18. Each recess 22 is a substantially cylindrical hole. That is, the shape of the concave portion 22 is substantially rectangular in the cross section orthogonal to the back surface 18b, and the cross sectional shape of the concave portion 22 orthogonal to the z direction is circular. The aspect ratio of the recess 22 (that is, the diameter of the recess 22 / the depth of the recess 22) is preferably 0.5 or more. Each recess 22 is arranged on the point light source 12 so that the light from the point light source 12 can be received by the inner surface of the recess 22. Accordingly, each concave portion 22 functions as an incident portion where light output from the corresponding point light source 12 is incident on the plate body 18.

  On the back surface 18b of the plate body 18, there is provided a layered reflecting portion 24 that reflects light propagating through the plate body 18 to the front surface 18a side. The reflecting unit 24 includes a plurality of semi-transmissive / semi-reflective reflective dots (first reflective dots) 24a that reflect light while partially transmitting light.

  The plurality of reflective dots 24a are arranged in a predetermined dot pattern. The dot pattern of the reflective dots 24a is adjusted so that the in-plane luminance perpendicular to the z direction is substantially uniform in the planar light emitted from the planar light generating plate. Examples of the predetermined dot pattern include those having a density distribution in which the reflective dots 24a are dense in a region on the central portion between adjacent point light sources 12 on the back surface 18b. An example of the reflective dot 24a is white ink. Since the light incident on the plate body 18 is diffused by the reflection of light by the plurality of reflection dots 24a, the planar light generation plate 14 functions as a diffusion plate.

  The light diffusion layer 20 laminated on the surface 18 a of the plate body 18 is for diffusing light emitted from the surface 18 a of the plate body 18. An example of the thickness of the light diffusion layer 20 is 30 μm to 5 mm. The light diffusing layer 20 is obtained by dispersing a light diffusing agent 20B on a base material 20A made of a transparent material. Examples of the refractive index of the transparent material are 1.4 to 1.65. The transparent material constituting the light diffusion layer 20 may be the same as the material of the plate body 18 or may be different. The material of the light diffusing agent 20B has a refractive index different from that of the base material 20A. Examples of the light diffusing agent 20B include organic particles such as styrene resin particles and methacrylic resin particles, potassium carbonate particles, silica particles, and silicone. Inorganic particles such as resin particles are used, and the particle diameter is usually 0.8 μm to 50 μm.

FIG. 2 is a diagram illustrating an example of an arrangement pattern of the recesses 22 formed on the back surface 18 b of the plate body 18. As shown in FIG. 2, the plurality of recesses 22 can be arranged at equal intervals L _{x in the} x direction and at equal intervals L _y in the y direction. In FIG. 2, as an example, the interval Lx in the x direction is larger than the interval Ly in the y direction, but the interval Ly may be larger than the interval Lx, or the interval Lx and the interval Ly may be the same. The space | interval Lx and the space | interval Ly can be made into the distance between the center axis lines of the recessed part 22, and are 10 mm-100 mm normally. Since the arrangement of the concave portions 22 and the arrangement of the point light sources 12 correspond to each other, when the concave portions 22 are arranged in the lattice shape shown in FIG. 2, the point light sources 12 are also arranged in the same lattice shape. .

  The planar light generating plate 14 can be manufactured by applying the reflective dots 24a to be the reflective portion 24 to the laminate in which the light diffusion layer 20 is laminated on the plate body 18 by screen printing, ink jet printing, or the like. it can. The plate body 18 can be manufactured by a method such as an injection molding method, an extrusion molding method, or a press molding method.

  In the surface light source device 10 having the above-described configuration, light output from each of the plurality of point light sources 12 enters the plate body 18 from the corresponding concave portion 22 of the plate body 18. The light that has entered the plate body 18 propagates through the plate body 18 and enters the light diffusion layer 20. The light incident on the light diffusion layer 20 is diffused by the light diffusion agent 20 </ b> B in the light diffusion layer 20 and then emitted from the surface 20 a of the light diffusion layer 20. Thus, since the light output from the point light source 12 propagates through the planar light generation plate 14 and is emitted, the surface light source device 10 converts the light from the plurality of point light sources 12 into a planar shape. It can be emitted as light.

  When the light propagating in the planar light generating plate 14 is reflected by the reflection dot 24a, it is reflected to the surface 18a side under conditions other than the total reflection condition, so that the reflected light from each of the plurality of reflection dots 24a is The light is emitted from the planar light generating plate 14 via the light diffusion layer 20. Further, the light is diffused by the reflection of the plurality of reflection dots 24a. Accordingly, it is possible to adjust the luminance uniformity of the light emitted from the planar light generating plate 14 by adjusting the dot pattern of the reflective dots 24a. In the above configuration, since the dot pattern of the reflective dots 24a is adjusted so that the luminance of the emitted light is substantially uniform, even if the planar light generating plate 14 is arranged on the point light source 12, the z direction It is possible to emit planar light having a substantially uniform luminance distribution in a plane orthogonal to the.

In addition, since the light transmitted through the reflecting portion 24 is reflected by the reflecting sheet 16 and then enters the plate body 18 again, the light output from the point light source 12 can be used effectively.

  Furthermore, since the light from the point light source 12 is incident on the plate body 18 through the inner surface of the recess 22, for example, the light is more dispersed than when the recess 22 is not formed and incident on a flat plane. Light propagates between the adjacent point light sources 12 and 12. Therefore, light is easily emitted from the area between the adjacent point light sources 12 and 12. Further, a light diffusion layer 20 is provided on the plate body 18, and the light emitted from the surface 18 a is further diffused and emitted from the planar light generating plate 14. Due to light diffusion by the light diffusion layer 20, the outgoing light angle distribution at each position on the surface 20a is easily aligned. Therefore, the surface light source device 10 can emit planar light with a substantially uniform luminance distribution in a plane orthogonal to the z direction. In the surface light source device 10, the uniformity of luminance can be further improved by adjusting at least one of the inner surface shape of the recess 22 and the diffusion state in the light diffusion layer 20. The diffusion state in the light diffusion layer 20 can be adjusted by the refractive index and concentration of the light diffusion agent 20B.

  Further, as described above, the light can be propagated to a place away from the recess 22 by the lens effect of the recess 22 when the light is incident on the plate body 18 via the recess 22. In the apparatus 10, it is possible to reduce the thickness and the number of light sources. Furthermore, since the plurality of point light sources 12 are arranged on the back surface 18b side of the planar light generating plate 14, local dimming (area control) is possible.

  From the viewpoint of making the luminance more uniform, as shown in FIG. 1, a layered light amount adjustment unit 26 that adjusts the emitted light amount of the light diffused in the light diffusion layer 20 is provided on the surface 20 a of the light diffusion layer 20. It is preferable. Similar to the reflection unit 24, the light amount adjustment unit 26 can be configured by arranging semi-transparent semi-reflective reflective dots (second reflective dots) 26a in a predetermined dot pattern. In this case, the light quantity emitted from the surface 20a is small in the dense region of the reflective dots 26a. Therefore, it is possible to further improve the uniformity of the luminance distribution of the planar light emitted from the planar light generating plate 14 by adjusting the dot pattern of the plurality of reflective dots 26a included in the light amount adjusting unit 26. is there. Examples of the dot pattern of the reflective dots 26a include those having a density distribution in which the reflective dots 26a are dense in the region immediately above the point light source 12. This is because with such a dot pattern, the amount of light in the region immediately above the point light source 12 can be suppressed. An example of the reflective dot 26a is white ink as in the case of the reflective dot 24a. However, it is preferable that the reflective dot 26a has a smaller transmittance and larger reflection than the reflective dot 24a.

  Thus, since the surface light source device 10 emits light output from the point light source 12 as surface light, it is preferably used as a backlight of a transmissive image display device 28 exemplified by a liquid crystal television. Can do.

  Next, an example of the configuration of the transmissive image display device 28 to which the surface light source device 10 shown in FIG. 1 is applied will be described. FIG. 3 is a perspective view showing a schematic configuration of the transmissive image display device 28 including the surface light source device 10 shown in FIG. In FIG. 3, the transmissive image display device 28 is disassembled to show main components. In FIG. 3, the planar light generation plate 14 is partially cut away, and the layered reflection unit 24 and the light amount adjustment unit 26 are schematically illustrated.

  As shown in FIG. 3, the transmissive image display device 28 includes a surface light source device 10 and a transmissive image display unit 30 provided on the surface light source device 10. Examples of the transmissive image display unit 30 include a liquid crystal display panel in which linearly polarizing plates 30B and 30C are arranged on both surfaces of a liquid crystal cell 30A. In this case, the transmissive image display device 28 is a liquid crystal display device (or a liquid crystal television). As the liquid crystal cell 30A and the polarizing plates 30B and 30C, those used in the transmissive image display device 28 such as a conventional liquid crystal display device can be used. Examples of the liquid crystal cell 30A include known liquid crystal cells such as TFT type and STN type.

  Since the transmissive image display device 28 includes the surface light source device 10, planar light whose luminance is uniformed in a plane orthogonal to the z direction illuminates the transmissive image display unit 30. As a result, the transmissive image display device 28 can display a high-quality image with reduced luminance unevenness on the transmissive image display unit 30. Further, since local dimming (area control) is possible in the surface light source device 10, the contrast of the image can be improved.

  From the viewpoint of more uniformly illuminating the transmissive image display unit 30, at least one transmissive image display device 28 is provided between the surface light source device 10 and the transmissive image display unit 30, as illustrated in FIG. It is also preferable that the optical sheet 32 is provided. Examples of the optical sheet 32 include a diffusion sheet that diffuses and irradiates light, or a lens sheet or prism sheet (luminance enhancement sheet) for directing light in a predetermined direction.

(Second Embodiment)
FIG. 4 is a drawing schematically showing a cross-sectional configuration of another embodiment of the surface light source device according to the present invention. The surface light source device 34 shown in FIG. 4 is different from the configuration of the surface light source device 34 in that a planar light generating plate 36 is employed instead of the planar light generating plate 14.

  The planar light generation plate 36 is different from the planar light generation plate 14 in that it does not have the light diffusion layer 20 (see FIG. 1) on the plate body 18, but the other configuration is the same as that of the planar light generation plate 14. The same. That is, the planar light generating plate 14 has a plate body 18. A plurality of recesses 22 are formed on the back surface 18b of the plate body 18, and a layered reflecting portion 24 is provided on the back surface 18b to reflect a part of the light propagating in the plate body 18 to the front surface 18a side. It has been. The reflection unit 24 is configured by arranging semi-transmission semi-reflection reflection dots 24a that reflect light while partially transmitting light in a predetermined dot pattern. The dot pattern of the reflective dots 24a is adjusted so that the in-plane luminance distribution orthogonal to the z direction is substantially uniform in the planar light output from the planar light generating plate.

  Also in the surface light source device 34, the light emitted from each of the plurality of point light sources 12 enters the plate main body 18 from the corresponding concave portion 22 of the plate main body 18. Therefore, for example, as compared with a case where no concave portion is formed and the light is incident on a flat plane, the light is dispersed and the light propagates between the adjacent point light sources 12 and 12. The light that has entered the plate body 18 propagates through the plate body 18 while being totally reflected mainly by the front surface 18a and the back surface 18b. Here, since the reflection part 24 having a plurality of reflection dots 24a is provided on the back surface 18b, reflection by the reflection dots 24a also occurs. Since this reflection is a reflection other than the total reflection condition, the light reflected by the reflection dot 24a is emitted from the surface 18a. Therefore, a part of the light incident on the plate body 18 from the recess 22 is emitted from the surface 18a while propagating through the plate body 18 by total reflection. As a result, the plate body 18 emits planar light from the surface 18 a of the plate body 18.

  In the above configuration, light can be diffused by reflection by each of the plurality of reflection dots 24a. Therefore, by adjusting the dot pattern of the reflective dots 24a, it is possible to adjust the brightness uniformity of the emitted light from the planar light generating plate 14. Since the reflection dots 24a are arranged so that the luminance of the emitted light is substantially uniform, the surface light source device 34 has a substantially uniform luminance distribution in the plane perpendicular to the z direction, as in the case of the surface light source device 10. Uniform planar light can be emitted. Furthermore, since the incident direction of light into the plate body 18 through the recess 22 differs depending on the inner surface shape of the recess 22, the planar light generating plate 14 can be adjusted by adjusting the inner surface shape of the recess 22. The uniformity of the brightness of the emitted light can be further improved.

  Also in the surface light source device 34, as in the case of the surface light source device 10, it is possible to reduce the thickness and the number of light sources and to perform local dimming (area control).

  From the viewpoint of further improving the uniformity of the brightness of the emitted light, it is preferable that a light amount adjusting unit 26 is provided on the surface 18a of the plate body 18 as shown in FIG. This is because the amount of light emitted from the surface 18 a can be adjusted by the light amount adjusting unit 26. As in the first embodiment, the light amount adjusting unit 26 may be configured such that a plurality of reflective dots (second reflective dots) 26a are arranged in a predetermined dot pattern.

  The surface light source device 34 can be applied as a backlight of the transmissive image display device 28 instead of the surface light source device 10. Even when the surface light source device 34 is employed, the transmissive image display unit 30 is illuminated with planar light having substantially uniform luminance. High quality images can be displayed. Since the surface light source device 34 can perform local dimming (area control), it is possible to improve the contrast of the image. Also in the present embodiment, it is preferable to provide at least one optical sheet 32 between the surface light source device 34 and the transmissive image display unit 30. In particular, since the planar light generating plate 36 does not have the light diffusing layer 20 on the plate body 18, at least one of the optical sheets 32 is a diffusing sheet from the viewpoint of uniformly illuminating the transmissive image display unit 30. preferable.

  The surface light source device 10, the planar light generation plate 14, and the transmissive image display device 28 according to the present invention have been described above, but the present invention is not limited to the above embodiment. For example, the recesses 22 are formed on the back surface 18b in an arrangement in which a rectangular lattice is a unit lattice, but may be arranged in a staggered manner as shown in FIG. In this case, the arrangement of the point light sources 12 has a corresponding staggered pattern. Further, the light amount adjusting unit 26 is not necessarily provided. Further, the reflection sheet 16 is not necessarily provided. For example, in the transmissive image display device 28 or the like, the bottom surface of the housing for installing the surface light source devices 10 and 34 can be mirror-finished.

  Furthermore, in the first and second embodiments, the white ink is exemplified as the reflective dots 24a and 26a. For example, the reflective dots 24a include minute irregularities formed on the back surface 18b so as to function as the reflective dots 24a. It can also be a structure. Moreover, the reflection part 24 can also be made by dispersing minute reflection films on the back surface 18b. The reflection dot 26a may be any one that can adjust the amount of light emitted from the surface 18a.

  In the said embodiment, although the shape of the recessed part 22 illustrated cylindrical shape, the inner surface is curving and you may exhibit the concave lens shape which tapered toward the surface side from the back surface side. The material of the plate body can be transparent glass.

  DESCRIPTION OF SYMBOLS 10 ... Surface light source device, 12 ... Point light source, 14 ... Planar light production | generation board, 18 ... Plate main body, 18a ... Surface of plate main body, 18b ... Back surface of plate main body, 20 ... Light diffusion layer, 22 ... Recessed part, 24 Reflector 24a Reflective dot (first reflective dot) 26 Light quantity adjusting unit 26a Reflective dot (second reflective dot) 28 Transmission image display device 30 Transmission image display unit 34 Surface light source device, 36... Planar light generating plate.

Claims (12)

A plurality of point light sources;
A planar light generating plate for emitting light from the plurality of point light sources as planar light;
With
The planar light generating plate is
A plate body having a plurality of back surfaces located on the side of the point light source, and a surface on the opposite side of the back surface from which light is emitted;
A reflective portion that is provided on the back surface and reflects at least part of the light propagating through the plate body to the front surface side;
Have
On the back surface, a plurality of recesses corresponding to the plurality of point light sources, and a plurality of recesses into which light from the corresponding point light sources is incident, are formed.
Surface light source device.   The surface light source device according to claim 1, wherein the reflection unit includes a plurality of first reflection dots that reflect at least part of light. The planar light generating plate further includes a light diffusion layer that is laminated on the surface of the plate body and diffuses light emitted from the surface.
The surface light source device according to claim 1 or 2. The planar light generation plate further includes a light amount adjustment unit that adjusts the amount of light emitted from the surface of the plate body.
The surface light source device as described in any one of Claims 1-3.   The surface light source device according to claim 4, wherein the light amount adjustment unit includes a plurality of second reflection dots that reflect at least a part of light. A plate body having a surface from which light is emitted and a back surface located on the opposite side of the surface;
A reflective portion that is provided on the back surface and reflects at least part of the light propagating through the plate body to the front surface side;
Have
A plurality of recesses are formed on the back surface,
Planar light generating plate.   The planar light generating plate according to claim 6, wherein the reflecting portion includes a plurality of first reflecting dots that reflect at least a part of light. The planar light generating plate further includes a light diffusion layer that is laminated on the surface of the plate body and diffuses light emitted from the surface.
The planar light generating plate according to claim 6 or 7. The planar light generation plate further includes a light amount adjustment unit that adjusts the amount of light emitted from the surface of the plate body.
The planar light generating plate according to any one of claims 6 to 8.   The planar light generation plate according to claim 9, wherein the light amount adjustment unit includes a plurality of second reflection dots that reflect at least a part of light. A plurality of point light sources;
A planar light generating plate for emitting light from the plurality of point light sources as planar light;
A transmissive image display unit that is provided on the planar light generation plate and is illuminated with planar light emitted from the planar light generation plate;
With
The planar light generating plate is
A plate body having a plurality of back surfaces located on the side of the point light source, and a surface on the opposite side of the back surface from which light is emitted;
A reflective portion that is provided on the back surface and reflects at least part of the light propagating through the plate body to the front surface side;
Have
On the back surface, a plurality of recesses corresponding to the plurality of point light sources, and a plurality of recesses into which light from the corresponding point light sources is incident, are formed.
Transmission type image display device. A light diffusion layer that is laminated on the surface of the plate main body and diffuses light emitted from the surface;
The transmissive image display device according to claim 11.

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