JP6850765B2 - Prism plate and light irradiation device - Google Patents

Description

The present invention relates to a prism plate and a light irradiation device.

Conventionally, a liquid crystal display device having a light source unit (light irradiation device) for illuminating a liquid crystal panel has been widely known. Among the light source units of such a liquid crystal display device, there is a method in which light is incident from the end surface side of the light guide plate and the light is incident on the liquid crystal panel via the light guide plate, and the light source is a point light source such as a light emitting diode. Are arranged at intervals. In a light source unit using such a point light source, the amount of light incident on the portion of the liquid crystal panel facing the light source and the portion between the light sources are different, and a difference in light intensity (luminance unevenness) occurs on the liquid crystal panel, resulting in a striped pattern. Etc. were occurring. Therefore, conventionally, improvements have been made to suppress the occurrence of such brightness unevenness (see, for example, Patent Document 1).

JP-A-2002-260427

As described above, the conventional light source unit tries to suppress the luminance unevenness on the liquid crystal panel, but the conventional light source unit is required to further suppress the luminance unevenness. As described above, the conventional light source unit is required to have a structure capable of uniformly distributing light by suppressing uneven brightness of light emitted from a plurality of light sources.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is a prism plate capable of suppressing uneven brightness of light emitted from a plurality of light sources and uniformly distributing light, and light irradiation. To provide the equipment.

In order to achieve the above object, the prism plate according to the present invention has a translucent base material having a pair of surfaces and a translucent material extending side by side to form a prism on one surface of the pair of surfaces. An incident-side prism surface having a plurality of incident-side prism portions, and an emitting-side prism surface having a plurality of translucent emitting-side prism portions extending side by side to form a prism on the other surface of the pair of surfaces. The shape of the incident side prism surface and the shape of the outgoing side prism surface are different from each other.

In the prism plate according to one aspect of the present invention, the incident side prism portion is convex from one surface of the pair of surfaces, and the incident side is concave from one surface of the pair of surfaces. One of the prism portions, the exit side prism portion is an exit side prism portion that is convex from the other surface of the pair of surfaces, and an emission side prism portion that is concave from the other surface of the pair of surfaces. Either one.

In the prism plate according to one aspect of the present invention, the plurality of incident side prism portions have the same shape on the incident side prism surface, and the plurality of exit side prism portions on the exit side prism surface. Have the same shape as each other.

In the prism plate according to one aspect of the present invention, the plurality of incident side prism portions have the same shape on the incident side prism surface, and the plurality of exit side prism portions on the exit side prism surface. A part of the prism portion and the rest of the plurality of ejection side prism portions have different shapes from each other.

In the prism plate according to one aspect of the present invention, the contour in the cross section facing the extending direction of the incident side prism portion is a curved surface, a part of a polygon, or a chevron.

In the prism plate according to one aspect of the present invention, the contour in the cross section facing the extending direction of the exit side prism portion is a curved surface, a part of a polygon, or a chevron.

In the prism plate according to one aspect of the present invention, a part of the emitting side prism portion is sharper than the rest of the emitting side prism portion.

In prism plate according to one embodiment of the present invention, the contour of the cross section facing the rest of the extending direction of the exit-side prism portion is a part of the curved or polygonal, one of the exit-side prism section The contour in the cross section facing the extending direction of the portion is chevron.

In the prism plate according to one aspect of the present invention, a part of the emitting side prism portion and the rest of the emitting side prism portion are repeatedly arranged in a predetermined combination.

In the prism plate according to one aspect of the present invention, the incident side prism portions are aligned with each other adjacent to each other or at a predetermined interval.

In the prism plate according to one aspect of the present invention, the emitting side prism portions are arranged adjacent to each other or arranged at a predetermined interval.

In order to achieve the above object, the light irradiation device according to the present invention abuts or approaches a plurality of light sources arranged side by side and the exit surfaces of the plurality of light sources so that the incident side prism surface faces the plurality of light sources. It is characterized in that it is provided with any of the above-mentioned prism plates arranged in the above-mentioned manner.

In the light irradiation device according to one aspect of the present invention, the plurality of emitting side prism portions extend in a direction orthogonal to the arrangement direction of the plurality of light sources, and are parallel to the extending directions of the plurality of incident side prism portions. It is extending.

According to the prism plate and the light irradiating device according to the present invention, it is possible to suppress uneven brightness of light emitted from a plurality of light sources and uniformly distribute the light.

It is a top view which shows roughly the structure of the light source unit which concerns on 1st Embodiment of this invention. It is sectional drawing which shows schematic the structure of the light source unit which concerns on 1st Embodiment of this invention. It is a partially enlarged plan view which shows roughly the structure of the light source unit which concerns on 1st Embodiment of this invention. It is a partially enlarged perspective view which shows roughly the structure of the prism plate which concerns on 1st Embodiment of this invention. It is a graph which shows the simulation result of the light distribution in the light source unit which concerns on 1st Embodiment of this invention. It is a graph which shows the simulation result of the light distribution in the light source unit which does not have a prism plate as a comparative example. It is a graph which shows the simulation result of the light distribution in the light source unit which has another prism plate as another comparative example. It is a side view which shows schematic structure of the prism plate which concerns on 2nd Embodiment of this invention. It is a side view which shows roughly the structure of the modification of the prism plate which concerns on 1st Embodiment of this invention. It is a side view which shows roughly the structure of the other modification of the prism plate which concerns on 1st Embodiment of this invention. It is a side view which shows roughly the structure of the modification of the prism plate which concerns on 2nd Embodiment of this invention. It is a side view which shows typically the structure of the other modification of the prism plate which concerns on 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view schematically showing the configuration of the light source unit 1 according to the first embodiment of the present invention, and FIG. 2 is a side view schematically showing the configuration of the light source unit 1. FIG. 3 is a partially enlarged plan view schematically showing the configuration of the light source unit 1, and FIG. 4 is a partially enlarged perspective view schematically showing the configuration of the prism plate 20 according to the embodiment of the present invention.

Hereinafter, for convenience of explanation, the emission directions of the plurality of light sources 10 in FIG. 1 are set to the lateral direction of the light source unit 1, and for convenience, the arrow a direction is set to the upper side, and the arrow b direction is set to the lower side. Further, the arrangement direction of the plurality of light sources 10 in FIG. 1 is the longitudinal direction of the light source unit 1, the arrow cd direction is used for convenience, the arrow c direction is the left side, and the arrow d direction is the right side. Further, the direction orthogonal to the arrangement direction of the plurality of light sources 10 in FIG. 1 is the depth direction of the light source unit 1 (direction perpendicular to the paper surface), the arrow ef direction is used for convenience, and the arrow e direction is the front side and the arrow f. The direction is the back side. In the following explanation, when the positional relationship and direction of each member are explained using up, down, left, and right, etc., the positional relationship and direction in the drawing are shown to the last, and the positional relationship and direction when incorporated into an actual device are shown. is not it.

As shown in FIGS. 1 to 4, the light source unit (light irradiation device) 1 according to the embodiment of the present invention is a plurality of light source units (light irradiation devices) 1 arranged side by side on a flexible printed circuit board (hereinafter, also referred to as an FPC board) (not shown). A light source 10 and a prism plate 20 arranged in contact with or close to the emission surfaces 10a of the plurality of light sources 10 are provided. The prism plate 20 is formed on a translucent base material 30 having a pair of surfaces (incident surface 30a, exit surface 30b) and an incident surface 30a as one surface of the pair of surfaces (incident surface 30a, exit surface 30b). An incident side prism surface 40 forming a prism and an emitting side prism surface 50 forming a prism on an exit surface 30b as the other surface of a pair of surfaces (incident surface 30a, exit surface 30b) are provided. The incident side prism surface 40 has a plurality of translucent incident side prism portions 41 extending side by side with each other, and the emitting side prism surface 50 has a plurality of translucent emitting side prism portions 51 extending side by side with each other. have. The shape of the incident side prism surface 40 and the shape of the outgoing side prism surface 50 are different from each other. The incident side prism surface 40 and the outgoing side prism surface 50 may be similar to each other. Hereinafter, the configuration of the light source unit 1 will be specifically described.

In the light source unit 1, a plurality of light sources 10 are provided on the surface of the FPC substrate (not shown). The prism plate 20 is arranged in contact with or close to the exit surfaces 10a of the plurality of light sources 10 so that the incident side prism surfaces 40 face each other. Specifically, the prism plates 20 are arranged on the emission surfaces 10a of the plurality of light sources 10. It is provided facing. The glass substrate 2 is provided on the upper side (arrow a direction) in the emission direction of the plurality of light sources 10 (short direction (arrow ab direction) of the light source unit 1).

As shown in FIGS. 1 to 4, the plurality of light sources 10 have a predetermined interval S1 in the arrangement direction of the plurality of light sources 10 (longitudinal direction of the light source unit 1 (arrow cd direction)) and are linear or substantially linear. They are arranged side by side. The arrangement form of the plurality of light sources 10 is not limited to this, and may be arranged in a curved or zigzag shape. The plurality of light sources 10 are electrically connected to the conductive layer (wiring) of the FPC substrate, and are connected to an external control module or the like (not shown) via the conductive layer (wiring) of the FPC substrate.

The plurality of light sources 10 irradiate light from the emission surface 10a toward the upper side (arrow a direction) in the lateral direction (arrow ab direction) of the light source unit 1 based on the instruction signal transmitted from the control module or the like. It has become. The plurality of light sources 10 are, for example, LEDs (light emitting diodes). The plurality of light sources 10 are not limited to this, and may be a known light emitting element such as an LD (laser diode), or may be a light emitting element having red, green, and blue LEDs, respectively.

In the light source unit 1, the prism plate 20 is formed in a rectangular plate shape or a substantially rectangular plate shape as shown in FIGS. 1 to 4. The prism plate 20 transmits light emitted from a plurality of light sources 10, and is formed of a translucent material, particularly a colorless and transparent synthetic resin. The prism plate 20 is made of, for example, polyethylene terephthalate, polyethylene naphthalate, acrylic resin, polycarbonate resin, polystyrene, polyolefin, cellulose acetate, weather-resistant vinyl chloride, active energy ray-curable resin and the like.

The prism plate 20 is formed on a base material 30 formed in a rectangular plate shape or a substantially rectangular plate shape, an incident side prism surface 40 formed on the incident surface 30a side of the base material 30, and an exit surface 30b side of the base material 30. It has a formed exit-side prism surface 50. The incident surface 30a of the prism plate 20 is arranged so as to face the exit surface 10a of the plurality of light sources 10. The incident surface 30a of the prism plate 20 is in contact with or close to the exit surface 10a of the plurality of light sources 10. The prism plate 20 receives the light emitted from the exit surfaces 10a of the plurality of light sources 10 on the incident surface 30a and emits the light from the exit surface 30b.

The base material 30, the incident side prism surface 40, and the exit side prism surface 50 in the prism plate 20 are integrally formed. The material of the prism plate 20 is not limited to this, and polyethylene terephthalate, polyethylene naphthalate, or a polycarbonate-based resin may be used as the base material 30, and the incident surface 30a and the exit surface 30b are made of an ultraviolet curable resin or the like. The entrance side prism surface 40 and the exit side prism surface 50 may be formed. Further, the incident side prism surface 40 is formed in the shape of one sheet, and the exit side prism surface 50 is formed in the shape of one sheet, and these sheets are formed on the incident surface 30a of the base material 30. The prism sheet 20 may be formed by sticking one or a plurality of each to the exit surface 30b.

The incident-side prism surface 40 has a plurality of light-transmitting incident-side prism portions 41, and the incident-side prism portions 41 extend side by side on the incident-side prism surface 40. The incident-side prism portion 41 is, for example, one of an incident-side prism portion 41 that is convex from the incident surface 30a and an incident-side prism portion 41 that is concave from the incident surface 30a. In the prism sheet 20 according to the present embodiment, as shown in FIGS. 3 and 4, the incident side prism portion 41 is convex from the incident surface 30a.

The emitting side prism surface 50 has a plurality of translucent emitting side prism portions 51, and the emitting side prism portions 51 extend side by side on the emitting side prism surface 50. The exit-side prism portion 51 is, for example, one of an exit-side prism portion 51 that is convex from the exit surface 30b and an exit-side prism portion 51 that is concave from the exit surface 30b. In the prism sheet 20 according to the present embodiment, as shown in FIGS. 3 and 4, the exit side prism portion 51 is convex from the exit surface 30b.

Further, on the incident side prism surface 40, the plurality of incident side prism portions 41 may have the same shape as each other, and a part of the plurality of incident side prism portions 41 and the plurality of incident side prism portions 41 may have the same shape. They may have different shapes from the rest of them. In the prism sheet 20 according to the present embodiment, as shown in FIGS. 3 and 4, the plurality of incident side prism portions 41 have the same or substantially the same shape as each other. Hereinafter, the incident side prism portion 41 of the prism sheet 20 according to the present embodiment is referred to as an incident side convex prism portion 42.

Further, on the emitting side prism surface 50, the plurality of emitting side prism portions 51 may have the same shape as each other, and a part of the plurality of emitting side prism portions 51 and the plurality of emitting side prism portions 51 may have the same shape. They may have different shapes from the rest of them. In the prism sheet 20 according to the present embodiment, as shown in FIGS. 3 and 4, a part of the plurality of emitting side prism portions 51 has a shape different from the rest of the plurality of emitting side prism portions 51. have. That is, the exit-side prism surface 50 has an emission-side convex prism portion 52 that is a part of the plurality of emission-side prism portions 51 and an emission-side pointed convex that is the rest of the plurality of emission-side prism portions 51. It has a strip prism portion 53.

In the prism plate 20, the plurality of incident-side convex prism portions 42 are located on the lower side (in the direction of arrow b) in the emission direction of the plurality of light sources 10 from the incident surface 30a (in the lateral direction of the light source unit 1 (direction of arrow ab)). The light sources 10 are arranged in parallel or substantially parallel to each other in the arrangement direction of the plurality of light sources 10 (longitudinal direction of the light source unit 1 (direction of arrow cd)). Further, the plurality of incident side convex prism portions 42 extend in a direction orthogonal to or substantially orthogonal to the arrangement direction of the plurality of light sources 10 (the depth direction of the light source unit 1 (arrow ef direction)). The plurality of incident-side convex prism portions 42 may extend obliquely with respect to the arrangement direction of the plurality of light sources 10 (longitudinal direction of the light source unit 1 (arrow cd direction)).

The incident-side convex prism portion 42 has, for example, a curved surface in a cross section facing the incident-side convex prism portion 42 in the extending direction (depth direction (arrow ef direction)). Specifically, as shown in FIGS. 3 and 4, the incident side convex prism portion 42 is an arc whose contour in the cross section facing the extending direction (depth direction (arrow ef direction)) has a constant curvature. The width of the incident side convex prism portion 42 in the longitudinal direction (arrow cd direction) is longer than the height in the lateral direction (arrow ab direction). The incident-side convex prism portion 42 is, for example, a part of a cylindrical shape or a substantially cylindrical shape, respectively, and is formed by a lenticular lens, a cylindrical lens, or the like.

The contour of the cross section of the incident side convex prism portion 42 facing the extending direction (depth direction (arrow ef direction)) is not limited to this, and may be a curved surface having a plurality of curvatures. The incident-side convex prism portion 42 is, for example, a part of an elliptical pillar shape or a substantially elliptical pillar shape, or a part of a semi-cylindrical shape or a substantially semi-cylindrical shape, and is formed by a lenticular lens or a cylindrical lens. Further, the contour of the cross section facing the extension direction (depth direction (arrow ef direction)) of the incident side convex prism portion 42 is not limited to this, and may be a part of a polygon such as a triangle, a pentagon, or a hexagon. Good. The cross section of the incident side convex prism portion 42 facing the extending direction (depth direction (arrow ef direction)) is, for example, a part of a polygon extending in an arc shape. The contour of the cross section of the incident side convex prism portion 42 in the extending direction is not limited to the above-mentioned shape, and may be another shape such that the incident side convex prism portion 42 protrudes from the incident surface 30a.

The incident side convex prism portions 42 extend side by side with each other at a predetermined interval S2. The width of the incident side convex prism portion 42 in the longitudinal direction (arrow cd direction) is longer than the width in the longitudinal direction (arrow cd direction) of the predetermined interval S2. A predetermined interval S2 may not be provided between the incident side convex prism portion 42 and the incident side convex prism portion 42 adjacent thereto. Further, the interval S2 does not have to have a constant width in the depth direction (arrow ef direction).

In the prism plate 20, the plurality of emission-side convex prism portions 52 are convex from the emission surface 30b toward the upper side (arrow a direction) in the emission direction (short direction (arrow ab direction)) of the plurality of light sources 10. There are, and they extend in parallel or substantially parallel to each other in the arrangement direction (longitudinal direction (arrow cd direction)) of the plurality of light sources 10. Further, the plurality of emitting side convex prism portions 52 extend in a direction (depth direction (arrow ef direction)) orthogonal to or substantially orthogonal to the arrangement direction of the plurality of light sources 10, and a plurality of incident side convex stripes. The prism portion 42 extends in parallel or substantially parallel to the extending direction (depth direction (arrow ef direction)). The plurality of emission-side convex prism portions 52 may extend obliquely with respect to the arrangement direction (longitudinal direction (arrow cd direction)) of the plurality of light sources 10.

The exit-side convex prism portion 52 has, for example, a curved surface in a cross section facing the extending direction (depth direction (arrow ef direction)) of the exit-side convex prism portion 52. Specifically, as shown in FIGS. 3 and 4, the exit-side convex prism portion 52 is an arc whose contour in the cross section facing the extending direction (depth direction (arrow ef direction)) has a constant curvature. The width of the exit-side convex prism portion 52 in the longitudinal direction (arrow cd direction) is longer than the height in the lateral direction (arrow ab direction). The exit-side convex prism portion 52 is, for example, a part of a cylindrical shape or a substantially cylindrical shape, respectively, and is formed by a lenticular lens, a cylindrical lens, or the like.

The contour of the cross section facing the extending direction (depth direction (arrow ef direction)) of the exit-side convex prism portion 52 is not limited to this, and may be a curved surface having a plurality of curvatures. The exit-side convex prism portion 52 is, for example, a part of an elliptical pillar shape or a substantially elliptical pillar shape, or a part of a semi-cylindrical shape or a substantially semi-cylindrical shape, and is formed by a lenticular lens or a cylindrical lens. Further, the contour of the cross section facing the extension direction (depth direction (arrow ef direction)) of the exit side convex prism portion 52 is not limited to this, and may be a part of a polygon such as a triangle, a pentagon, or a hexagon. Good. The cross section of the emitting side convex prism portion 52 facing the extending direction (depth direction (arrow ef direction)) is, for example, a part of a polygon extending in an arc shape. The emitting side convex prism portion 52 may be the same as, substantially the same as, or substantially different from the incident side convex prism portion 42. The contour of the cross section of the exit-side convex prism portion 52 in the extending direction is not limited to the above-mentioned shape, and may be another shape such that the exit-side convex prism portion 52 protrudes from the exit surface 30b.

In the prism plate 20, the plurality of exit-side pointed convex prism portions 53 are directed from the emission surface 30b toward the upper side (arrow a direction) in the emission direction (short direction (arrow ab direction)) of the plurality of light sources 10. It is convex and extends in the direction in which the plurality of light sources 10 are arranged (longitudinal direction (arrow cd direction)) alternately with the convex prism portion 52 on the exit side. That is, the exit-side pointed ridge prism portion 53 is formed between the exit-side ridge prism portions 52 adjacent to each other. Further, the plurality of emitting side pointed convex prism portions 53 extend in a direction (depth direction (arrow ef direction)) orthogonal to or substantially orthogonal to the arrangement direction of the plurality of light sources 10, respectively, and a plurality of incident sides. The ridge prism portion 42 and the exit side ridge prism portion 52 extend in parallel or substantially parallel to the extension direction (depth direction (arrow ef direction)). The plurality of emission-side pointed convex prism portions 53 may extend obliquely with respect to the arrangement direction (longitudinal direction (arrow cd direction)) of the plurality of light sources 10. There is no space between the exit-side convex ridge prism portion 52 and the exit-side pointed ridge prism portion 53. The distance between the exit-side convex ridge prism portion 52 and the exit-side pointed ridge prism portion 53 is not limited to this, and a predetermined distance may be provided.

Each of the plurality of exit-side pointed ridge prism portions 53 is formed to be sharper than the exit-side ridge prism portion 52. For example, the width of the plurality of exit-side pointed ridge prism portions 53 in the longitudinal direction (arrow cd direction) is smaller than the width of each of the plurality of exit-side ridge prism portions 52 in the longitudinal direction (arrow cd direction). There is. Further, the heights of the plurality of light sources 10 in the plurality of emitting side pointed convex prism portions 53 in the emitting direction (short direction (arrow ab direction)) are set to the heights of the plurality of light sources in the plurality of emitting side convex prism portions 52. It is higher than the height of 10 in the emission direction (short direction (arrow ab direction)).

The exit-side pointed convex prism portion 53 has, for example, a chevron-shaped contour in a cross section facing the extending direction (depth direction (arrow ef direction)) of the exit-side pointed convex prism portion 53. Specifically, as shown in FIGS. 3 and 4, each of the exit-side pointed convex prism portions 53 faces the extending direction (depth direction (arrow ef direction)) of the exit-side pointed convex prism portion 53. The top 54 in the contour in the cross section is curved. Each of the exit-side pointed convex prism portions 53 has a pair of inclinations whose contours in a cross section facing the extending direction (depth direction (arrow ef direction)) of the exit-side pointed convex prism portion 53 follow the top 54 and face each other. It has straight lines 55 and 56. The pair of inclined straight lines 55 and 56 are inclined in a direction away from each other toward the lower side (arrow b direction) in the emission direction (short direction (arrow ab direction)) of the plurality of light sources 10. The angle formed by the pair of inclined straight lines 55 and 56 is an acute angle.

The top portion 54 of the exit-side pointed convex prism portion 53 is not limited to this, and may be a straight line where a pair of inclined straight lines 55 and 56 intersect. Further, the angle formed by the pair of inclined straight lines 55 and 56 is not limited to this, and may be a right angle or an obtuse angle. Further, the contour in the cross section facing the extension direction (depth direction (arrow ef direction)) of the exit-side pointed convex prism portion 53 is not limited to this, and is a part of a polygon such as a triangle, a pentagon, or a hexagon. You may. The plurality of ejection side pointed convex prism portions 53 are formed by, for example, a prism lens having a triangular prism shape or a substantially triangular prism shape.

The glass substrate 2 is arranged to face the exit surface 30b of the prism plate 20. The exit surface 30b of the prism plate 20 is in contact with or close to the end surface 2a of the glass substrate 2. The glass substrate 2 receives the light emitted from the exit surface 30b of the prism plate 20 at the end surface 2a of the glass substrate 2 and emits the light from the exit surface 2b of the glass substrate 2. After that, the light emitted from the exit surface 2b of the glass substrate 2 is incident on the liquid crystal panel (not shown).

As described above, in the light source unit 1 according to the embodiment of the present invention, the incident side convex prism portion 42 of the incident side prism surface 40 is arranged in contact with or close to the exit surface 10a of the plurality of light sources 10. A prism plate 20 having an exit-side convex prism portion 52 and an exit-side pointed convex prism portion 53 on the exit-side prism surface 50 is provided. In the prism plate 20, the incident light from the plurality of light sources 10 is diffused by the R-shaped incident side convex prism portion 42 so that the light reaches the exit surface 30b of the prism plate 20 uniformly. Then, the emitted light of the prism plate 20 is diffused through the emitting side convex prism portion 52, and is collected (started up) through the emitting side sharp convex prism portion 53. As a result, even if the light is diffused through the emitting side convex prism portion 52 to make the light uniform, the light between the adjacent light sources 10 is weakened, but the light is collected by the emitting side sharp convex prism portion 53. The light enhances the brightness between the adjacent light sources 10. Therefore, the light incident from the plurality of light sources 10 becomes uniform light through the prism plate 20 and is emitted from the glass substrate 2.

FIG. 5 is a graph showing a simulation result of a light distribution in the light source unit 1 according to the embodiment of the present invention. In the light source unit 1 according to the embodiment of the present invention, as shown in the simulation result of the light distribution in the light source unit 1 shown in FIG. 5, the light source arranged on the emission surface 30b of the prism plate 20 is directly above the light source 10. The relative luminous intensity ratio between the luminous intensity L1 measured in 1 and the luminous intensity L2 measured immediately above the interval S1 between the light source 10 can be made substantially the same when the light distribution angle is 0 degrees or in the vicinity of 0 degrees.

Therefore, in the light source unit 1 according to the embodiment of the present invention, the luminous intensity LC1 measured directly above the light source 10 in the simulation result of the light distribution in the light source unit 1 having no prism plate 20 as a comparative example shown in FIG. Since the relative luminosity ratio can be made smaller than the relative luminosity ratio with the luminosity LC2 measured directly above the interval S1 between the light sources 10, the uneven brightness of the light emitted from the plurality of light sources 10 can be suppressed and the light can be emitted. Light can be distributed uniformly.

Further, FIG. 7 shows a simulation result of the light distribution in the light source unit 1 having another prism plate as another comparative example. The other prism plate has the same prism surface on the entrance surface and the exit surface. More specifically, the other prism plate has a prism surface similar to the incident side prism surface 40 having a plurality of incident side convex prism portions 42 of the prism plate 20 on the incident surface and the exit surface. As shown in FIG. 7, in the comparative example in which the incident surface and the exit surface have the same R-shaped prism surface, the luminous intensity LC3 measured directly above the light source 10 and the luminous intensity LC4 measured directly above the light source 10 The relative luminous intensity ratio of the light source unit 1 according to the embodiment of the present invention is larger than that of the light source unit 1 according to the embodiment of the present invention (FIG. 5). It can be seen that the light can be uniformly distributed by suppressing the uneven brightness of the light emitted from the light source.

As described above, according to the prism plate 20 and the light source unit 1 according to the first embodiment of the present invention, it is possible to suppress uneven brightness of light emitted from a plurality of light sources and uniformly distribute the light. it can.

Next, the prism plate 60 according to the second embodiment of the present invention will be described. The prism plate 60 according to the second embodiment of the present invention has a prism surface 40 on the incident side and a prism surface 50 on the exit side, respectively, with respect to the prism plate 20 according to the first embodiment of the present invention described above. It has different incident side prism surfaces 61 and outgoing side prism surfaces 62. Hereinafter, the configurations having the same or similar functions as those of the prism plate 20 according to the first embodiment of the present invention described above are designated by the same reference numerals, the description thereof will be omitted, and different configurations will be described.

FIG. 8 is a side view schematically showing the configuration of the prism plate 60 according to the second embodiment of the present invention. In the prism sheet 60, as shown in FIG. 8, the incident side prism surface 61 has a plurality of incident side concave prism portions 63 recessed from the incident surface 30a as incident side prism portions. The plurality of incident side concave prism portions 63 have the same or substantially the same shape as each other. The contour of the incident side concave prism portion 63 in the cross section facing the extending direction (depth direction (arrow ef direction)) has the same shape as the incident side convex prism portion 42 described above.

Further, in the prism sheet 60, as shown in FIG. 8, the exit-side prism surface 62 has a plurality of exit-side prism portions 64 recessed from the exit surface 30b as emission-side prism portions. In the prism sheet 60, as shown in FIG. 8, a part of the plurality of emitting side prism portions 64 has a shape different from the rest of the plurality of emitting side prism portions 64. That is, the exit-side prism surface 62 has an emission-side concave prism portion 65 that is a part of the plurality of emission-side prism portions 64 and an emission-side pointed concave that is the rest of the plurality of emission-side prism portions 64. It has a strip prism portion 66. The contour in the cross section of the exit-side concave prism portion 65 facing the extending direction (depth direction (arrow ef direction)) has the same shape as the above-mentioned exit-side convex prism portion 52, and has a pointed shape on the exit side. The contour in the cross section facing the extending direction (depth direction (arrow ef direction)) of the concave prism portion 66 has the same shape as the above-mentioned ejection side pointed convex prism portion 53.

The prism plate 60 according to the second embodiment of the present invention having the above-described configuration also operates in the same manner as the prism plate 20 according to the first embodiment of the present invention described above, and is emitted from a plurality of light sources. It is possible to suppress uneven brightness of the light and distribute the light uniformly.

Next, a modified example of the prism plate 20 according to the first embodiment of the present invention will be shown. As described above, on the emitting side prism surface 50, the plurality of emitting side prism portions 51 may have the same shape as each other. For example, as shown in FIG. 9, the exit-side prism surface 50 of the prism plate 20 may have only the exit-side pointed convex prism portion 53 as the exit-side prism portion 51. Further, as shown in FIG. 10, the emitting side prism surface 50 of the prism plate 20 has only the emitting side convex prism portion 52 as the emitting side prism portion 51, and the incident side prism surface 40 of the prism plate 20. May have an incident-side pointed ridge prism portion 43 similar to the exit-side ridged ridge prism portion 53 as the incident-side prism portion 41.

Next, a modified example of the prism plate 60 according to the second embodiment of the present invention will be shown. As described above, on the emitting side prism surface 62, the plurality of emitting side prism portions 64 may have the same shape as each other. For example, as shown in FIG. 11, the exit-side prism surface 62 of the prism plate 60 may have only the exit-side pointed concave prism portion 66 as the exit-side prism portion 64. Further, as shown in FIG. 12, the emitting side prism surface 62 of the prism plate 60 has only the emitting side concave prism portion 65 as the emitting side prism portion 64, and the incident side prism surface 61 of the prism plate 60. May have an incident side sharp concave prism portion 67 similar to the outgoing side sharp concave prism portion 66 as an incident side prism portion.

Further, as a modification of the prism plate 20 according to the first embodiment of the present invention described above, the prism plate 20 has a configuration in which the incident side prism surface 40 has the same configuration as the above-mentioned exit side prism surface 50. Often, the exit-side prism surface 50 may have the same configuration as the above-mentioned incident-side prism surface 40. Similarly, as a modification of the prism plate 60 according to the second embodiment of the present invention described above, the prism plate 60 has an incident side prism surface 61 having the same configuration as the above-mentioned emitting side prism surface 62. The emitting side prism surface 62 may have the same configuration as the incident side prism surface 61 described above.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and includes all aspects included in the concept of the present invention and the scope of claims. In addition, each configuration may be selectively combined as appropriate so as to achieve at least a part of the above-mentioned problems and effects. For example, the shape, material, arrangement, size, etc. of each component in the above embodiment can be appropriately changed depending on the specific usage mode of the present invention. Further, the light source unit 1 in the above embodiment is configured so that the emitted light is incident on the glass substrate 2, but the present invention is not limited to this. For example, it may be configured so that the emitted light is incident on a transparent substrate made of resin instead of glass, or it may be configured to irradiate the emitted light on a reflector, a diffuser, or the like instead of the transparent body. Good.

1 ... light source unit, 2 ... glass substrate, 10 ... light source, 10a ... exit surface, 20, 60 ... prism plate, 30 ... base material, 30a ... incident surface, 30b ... exit surface, 40, 61 ... incident side prism surface, 41 ... Incident side prism portion, 42 ... Incident side convex prism portion, 43 ... Incident side pointed convex prism portion, 50, 62 ... Exit side prism surface, 51, 64 ... Exit side prism portion, 52 ... Exit side convex Striped prism part, 53 ... Exiting side pointed convex prism part, 54 ... Top, 55, 56 ... Straight line, 63 ... Incident side concave prism part, 65 ... Exiting side concave prism part, 66 ... Exiting side pointed concave Striped prism portion, 67 ... Incident side pointed concave prism portion, S1, S2 ... Interval

Claims (11)

A translucent substrate with a pair of surfaces and
An incident-side prism surface having a plurality of light-transmitting incident-side prism portions extending side by side to form a prism on one surface of the pair of surfaces, and an incident-side prism surface.
It is provided with an emitting side prism surface having a plurality of translucent emitting side prism portions extending side by side, forming a prism on the other surface of the pair of surfaces.
The shape of the incident side prism surface and the outgoing side prism surface are different from each other.
On the incident side prism surface, the plurality of incident side prism portions have the same shape as each other.
On the emitting side prism surface, a part of the plurality of emitting side prism portions and the rest of the plurality of emitting side prism portions have different shapes from each other.
The incident side prism portion aims to diffuse light with respect to incident light from a plurality of light sources.
A part of the emitting side prism portion is intended to collect light with respect to incident light from the plurality of light sources diffused and incident by the incident side prism portion, and is among the emitting side prism portions. The rest of the light is diffused by the incident side prism portion to diffuse the incident light from the plurality of light sources .
A part of the emitting side prism portion is sharper than the rest of the emitting side prism portion, and the height of a part of the emitting side prism portion is the height of the emitting side prism portion. Higher than the remaining height,
The contour of a part of the exit-side prism portion facing the extending direction has a pair of straight lines facing each other that incline in the direction away from each other as the direction away from the top.
The contour in a cross section facing the rest of the extending direction of the exit-side prism section, Ri arc der having a predetermined curvature,
A prism plate characterized in that a part of the emitting side prism portion and the rest of the emitting side prism portion are repeatedly arranged in a predetermined combination. The incident-side prism portion is either one of an incident-side prism portion that is convex from one surface of the pair of surfaces and an incident-side prism portion that is concave from one surface of the pair of surfaces.
The exit-side prism portion is characterized by being either one of an exit-side prism portion that is convex from the other surface of the pair of surfaces and an exit-side prism portion that is concave from the other surface of the pair of surfaces. The prism plate according to claim 1. The prism plate according to claim 1 or 2, wherein the contour of the cross section of the incident side prism portion facing the extending direction is a curved surface, a part of a polygon, or a chevron shape. The prism plate according to any one of claims 1 to 3, wherein the top of the contour in a cross section facing the extending direction of a part of the emitting side prism portion is a curved line. The prism plate according to any one of claims 1 to 4, wherein the pair of straight lines having a contour in a cross section facing the extending direction of a part of the emitting side prism portion has an acute angle. .. The prism plate according to any one of claims 1 to 5 , wherein the prism portions on the incident side are arranged adjacent to each other or arranged at a predetermined interval. The prism plate according to any one of claims 1 to 6 , wherein the emitting side prism portions are arranged adjacent to each other or arranged at a predetermined interval. With multiple light sources arranged side by side,
The prism plate according to any one of claims 1 to 7 is provided with a prism plate according to any one of claims 1 to 7, which is arranged in contact with or close to the exit surfaces of the plurality of light sources so that the incident side prism surfaces face each other. Light irradiation device. 8. The invention according to claim 8 , wherein the plurality of emitting side prism portions extend in a direction orthogonal to the arrangement direction of the plurality of light sources, and extend in parallel with the extending directions of the plurality of incident side prism portions. Light irradiation device. The prism plate according to claim 1, wherein the rest of the emitting side prism portion has a width longer than a height. Wherein a portion of the exit-side prism portion, wherein the remaining one of the exit-side prism unit, a prism plate of claim 1, wherein the are arranged alternately.

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