JP2018181729A - Luminaire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a luminaire which radiates light having a favorable luminance distribution from an emission surface of a light guide plate.SOLUTION: The luminaire includes the light guide plate, a first light source and a plurality of prisms. The light guide plate has a first main surface, and a second main surface positioned on the opposite side form the first main surface and including a plurality of surfaces. The first light source radiates laser light along a first radiation direction. The plurality of prisms are provided on the second main surface. The laser light travels in a first travel direction in a plan view. The second main surface has a first region and a second region arranged side by side sequentially in the first travel direction. The light emitted by the first light source enters the first region. The plurality of prisms include a plurality of first prisms in the second region. In a cross-sectional view, a distance with the first main surface of the first region is longer than that of the second region. The first radiation direction is inclined with respect to the first main surface.SELECTED DRAWING: Figure 4

Description

  Embodiments of the present invention relate to a lighting device.

  For example, a display device such as a liquid crystal display device includes a display panel having pixels and a lighting device such as a backlight for lighting the display panel. The illumination device includes a light source that emits light and a light guide plate to which light from the light source is emitted. The light from the light source enters the light guide plate from the side surface, propagates in the light guide plate, and exits from the exit surface corresponding to one main surface of the light guide plate.

  However, if the light source is disposed outside the side surface of the light guide plate, the entire lighting device becomes large, and it becomes difficult to make the display device compact.

JP 2004-38108 A JP, 2011-238484, A

  An object in one aspect of the present disclosure is to provide a lighting device with a reduced size.

  A lighting device according to an embodiment includes a light guide plate, a first light source, and a plurality of prisms. The light guide plate has a first main surface, and a second main surface opposite to the first main surface and including a plurality of surfaces. The first light source emits a laser beam along a first irradiation direction. The plurality of prisms are provided on the second major surface. The laser beam travels in a first traveling direction in plan view. The second main surface has a first region and a second region arranged in order along the first traveling direction. The light emitted by the first light source is incident on the first area. The plurality of prisms includes a plurality of first prisms in the second region. In a cross sectional view, the distance to the first major surface is longer in the order of the first region and the second region. The first irradiation direction is inclined with respect to the first main surface.

FIG. 1 is a perspective view showing a schematic configuration of the display device according to the first embodiment. FIG. 2 is a schematic cross-sectional view of the display device according to the first embodiment. FIG. 3 is a schematic plan view of the lighting device according to the first embodiment. FIG. 4 is a schematic cross-sectional view of the light guide plate according to the first embodiment. FIG. 5 is a schematic cross-sectional view of a part of the lighting device according to the first embodiment. FIG. 6 is an enlarged cross-sectional view of the first prism according to the first embodiment. FIG. 7 is an enlarged cross-sectional view of the second prism according to the first embodiment. FIG. 8 is a view showing the luminance distribution of the light guide plate according to the comparative example. FIG. 9 is a view showing a luminance distribution of a light guide plate according to another comparative example. FIG. 10 is a schematic cross-sectional view of a light guide plate according to the comparative example of FIG. FIG. 11 is a view showing an example of the luminance distribution of the light guide plate according to the first embodiment. FIG. 12 is a schematic cross-sectional view of the illumination device according to the second embodiment. FIG. 13 is a schematic cross-sectional view of a lighting device according to a third embodiment. FIG. 14 is a schematic cross-sectional view of a part of the lighting device according to the fourth embodiment. FIG. 15 is a schematic cross-sectional view of a part of the lighting device according to the fifth embodiment. FIG. 16 is a schematic cross-sectional view of a part of the lighting device according to the sixth embodiment. FIG. 17 is a schematic cross-sectional view of a part of the lighting device according to the seventh embodiment. FIG. 18 is a schematic cross-sectional view of a lighting device according to an eighth embodiment. FIG. 19 is a schematic cross-sectional view of a portion of a lighting device according to a ninth embodiment.

Several embodiments will be described with reference to the drawings.
The disclosure is merely an example, and those that can be easily conceived of as appropriate changes while maintaining the gist of the invention are naturally included in the scope of the present invention. In addition, the drawings may be schematically represented as compared to the actual embodiment in order to clarify the description, but are merely examples and do not limit the interpretation of the present invention. In each of the drawings, reference numerals may be omitted for identical or similar elements arranged in succession. In addition, in the present specification and the drawings, components having the same or similar functions as those described above with reference to the drawings already described may be denoted by the same reference symbols, and overlapping detailed descriptions may be omitted.

  In addition, in the present specification, “α includes A, B or C”, “α includes any of A, B and C”, “α is one selected from the group consisting of A, B and C The expression “including” does not exclude the case where α includes a plurality of combinations of A to C unless otherwise specified. Furthermore, these expressions do not exclude the case where α contains other elements.

  In each embodiment, a transmissive liquid crystal display device is disclosed as an example of the display device. In addition, a backlight of a liquid crystal display device is disclosed as an example of a lighting device. However, each embodiment does not prevent the application of the individual technical idea disclosed in each embodiment to other types of display devices and lighting devices. As another type of display device, for example, a liquid crystal display device having a function of reflection type that reflects external light and uses this reflected light for display in addition to the function of transmission type, Micro Electro Mechanical System (MEMS) For example, a display device having a mechanical display panel in which the shutter functions as an optical element is assumed. As another type of lighting device, for example, a front light disposed on the front of a display device is assumed. Also, the lighting device may be used in applications different from the lighting of the display device.

First Embodiment
FIG. 1 is a perspective view showing a schematic configuration of the display device 1 according to the first embodiment. The display device 1 can be used for various devices such as, for example, a smartphone, a tablet terminal, a mobile phone terminal, a personal computer, a television receiver, an in-vehicle device, a game device, and a wearable terminal.

The display device 1 includes a display panel 2, a lighting device 3 as a backlight, a drive IC chip 4 for driving the display panel 2, and flexible circuit boards FPC 1 and FPC 2 for transmitting control signals to the display panel 2 and the lighting device 3. And have. For example, the flexible circuit boards FPC1 and FPC2 are connected to a control module that controls the operation of the display panel 2 and the lighting device 3.
The display panel 2 includes a first substrate SUB1 (array substrate) and a second substrate SUB2 (opposite substrate) opposed to the first substrate SUB1. The display panel 2 has a display area DA for displaying an image. The display panel 2 includes, for example, a plurality of pixels PX arranged in a matrix in the display area DA.

  The illumination device 3 includes a first light source LS1, a second light source LS2, and a light guide plate LG facing the first substrate SUB1. The first light source LS1 faces one end of the lower surface (the surface not facing the first substrate SUB1) of the light guide plate LG, and the second light source LS2 is the lower surface (the surface not facing the first substrate SUB1) of the light guide plate LG. Opposite the other end. Although each of the light sources LS1 and LS2 is shown in FIG. 1, in actuality, a plurality of first light sources LS1 and a plurality of second light sources LS2 are provided (see FIG. 3).

  As shown in FIG. 1, a first direction X, a second direction Y, and a third direction Z are defined. The respective directions X, Y and Z are, for example, orthogonal to one another. In the present disclosure, viewing the display device 1 from a direction parallel to the third direction Z is referred to as a plan view. Also, viewing a cross section of the display device 1 parallel to the XZ plane is referred to as a cross sectional view. In the example of FIG. 1, each of the substrates SUB1 and SUB2 and the light guide plate LG have long sides along the first direction X and short sides along the second direction Y, and the shape in plan view is rectangular. . However, the shape of each of the substrates SUB1 and SUB2 and the light guide plate LG is not limited to this, and the shape in plan view may be another shape such as a square or a circle.

  FIG. 2 is a schematic cross-sectional view of the display device 1 parallel to the XZ plane. The display panel 2 further includes a sealing material SL and a liquid crystal layer LC. The substrates SUB1 and SUB2 are bonded together by a sealing material SL. The liquid crystal layer LC is sealed between the sealing material SL and each of the substrates SUB1 and SUB2.

  The first polarizing plate PL1 is attached to the lower surface (the surface facing the light guide plate LG) of the first substrate SUB1. A second polarizing plate PL2 is attached to the upper surface (the surface not facing the first substrate SUB1) of the second substrate SUB2. The polarization axes of the polarizing plates PL1 and PL2 are orthogonal to each other.

  The light guide plate LG has a first main surface 51 facing the display panel 2, a second main surface 52 opposite to the first main surface 51, a first side surface 53, and a second surface opposite to the first side surface 53. It has a side 54. The first light source LS1 faces the end of the second main surface 52 on the side of the first side 53, and the second light source LS2 faces the end of the second main surface 52 on the side of the second side 54. A lens or the like between the first light source LS1 and the end of the second main surface 52 on the first side 53 side, or between the second light source LS2 and the end of the second main surface 52 on the second side 54 An optical element may be further disposed to adjust the width and angle of the light from each of the light sources LS1 and LS2.

  The first light source LS1 emits diffused light having a spread centered on the first irradiation direction DL1 to the vicinity of the end on the first side surface 53 side of the second main surface 52. The second light source LS2 emits diffused light having a spread centered on the second irradiation direction DL2 to the vicinity of the end on the second side 54 side of the second main surface 52. The irradiation directions DL1 and DL2 are, for example, opposite directions in the first direction X, and are inclined in the third direction Z with respect to the first major surface 51, respectively. That is, in the present embodiment, the first irradiation direction DL1 does not coincide with the first direction X in a cross sectional view. However, in the case of a plan view, the first irradiation direction DL1 matches the first direction X. As a light emitting element of each light source LS1, LS2, laser light sources, such as a semiconductor laser which emits the polarized laser beam, can be used, for example.

  Each of the light sources LS1 and LS2 may include a plurality of light emitting elements that emit light of different colors. For example, when each of the light sources LS1 and LS2 includes three light emitting elements that emit red, green and blue light, light of mixed color (for example, white) of these colors can be obtained.

  The display device 1 includes a prism sheet PS between the display panel 2 and the light guide plate LG. Furthermore, the display device 1 includes a diffusion sheet DS (a diffusion layer) between the prism sheet PS and the display panel 2. For example, the prism sheet PS includes a large number of prisms extending in parallel to the second direction Y. These prisms are formed, for example, on the lower surface (the surface facing the light guide plate LG) of the prism sheet PS. However, these prisms may be formed on the upper surface of the prism sheet PS (the surface facing the display panel 2).

  In FIG. 2, an example of an optical path of light emitted by the first light source LS1 is shown by a broken line, and an example of an optical path of light emitted by the second light source LS2 is shown by a dashed dotted line. The light emitted from the first light source LS1 enters the light guide plate LG from the end on the first side surface 53 side of the second main surface 52, propagates through the light guide plate LG while being reflected by the main surfaces 51 and 52, and eventually The light is emitted from the first major surface 51 outside the total reflection condition of the one major surface 51. The light emitted from the second light source LS2 enters the light guide plate LG from the end on the second side surface 54 side of the second main surface 52, propagates through the light guide plate LG while being reflected by the respective main surfaces 51, 52, and eventually The light is emitted from the first major surface 51 outside the total reflection condition of the one major surface 51. As described above, the first major surface 51 corresponds to an emission surface from which light is emitted. In such a configuration, since the irradiation directions DL1 and DL2 are inclined with respect to the first main surface 51, the light emitted from the laser light sources LS1 and LS2 is not reflected by the main surfaces 51 and 52. Direct emission from each side surface 54, 53 can be suppressed. That is, since it is difficult for the laser beam to transmit to the outside from the vicinity of the first side surface 53 or the second side surface 54, the utilization efficiency of the laser beam is improved.

  The prism sheet PS converts the light emitted from the first major surface 51 into light substantially parallel to the third direction Z. Here, “light substantially parallel to the third direction Z” is not only light strictly parallel to the third direction Z, but also when the inclination with respect to the third direction Z is emitted from the first major surface 51 In comparison, it contains light converted sufficiently small by the prism sheet PS. From the viewpoint of maintaining the polarization of the light from the light sources LS1 and LS2, it is preferable that the prisms of the prism sheet PS be formed on the lower surface. The light passing through the prism sheet PS is diffused by the diffusion sheet DS and is irradiated to the display panel 2. Even when the viewing angle of light passing through the prism sheet PS is narrow, the viewing angle can be expanded by diffusing this light with the diffusion sheet DS.

  When the light from each of the light sources LS1 and LS2 reaches the display panel 2 in a sufficiently polarized state, the first polarizing plate PL1 may be omitted. When the first polarizing plate PL1 is omitted, for example, by increasing the light transmittance of the substrates SUB1 and SUB2, it is possible to obtain a so-called transparent liquid crystal display device in which the background of the display device 1 can be seen through.

  FIG. 3 is a schematic plan view of the lighting device 3. In the example of this figure, the eight first light sources LS1 are arranged along the end (A1 in FIG. 3) on the first side 53 side of the light guide LG, and the end on the second side 54 of the light guide LG Eight second light sources LS2 are arranged along (A5 in FIG. 3). The intensity of light emitted by the first light source LS1 is the highest at the first optical axis AX1, and the intensity of light emitted by the second light source LS2 is the highest at the second optical axis AX2. The light sources LS1 and LS2 overlap with both end portions of the light guide plate LG in the thickness direction (third direction Z) of the light guide plate LG. In the example of FIG. 2, all of the light sources LS1 and LS2 overlap the light guide plate LG, but a part of the light sources LS1 and LS2 may overlap the light guide plate LG.

  The light sources LS1 and LS2 are alternately arranged in the second direction Y as illustrated. That is, the first optical axis AX1 'of the light emitted by the first light source LS1 in the first traveling direction DL1' (the first irradiation direction DL1 in plan view) and the second light source LS2 in the second traveling direction DL2 '(plan view) The second optical axis AX2 ′ of the light emitted in the second irradiation direction DL2) is offset from each other in the second direction Y. The first optical axis AX1 'and the second optical axis AX2' may be aligned in the second direction Y.

  FIG. 4 is a schematic cross-sectional view of the light guide plate LG parallel to the XZ plane. The first major surface 51 of the light guide plate LG is a plane parallel to the first direction X and the second direction Y. The second main surface 52 includes a plurality of surfaces, and includes a first area A1, a second area A2, a third area A3, a fourth area A4, and a fifth area A5. As shown in the plan view of FIG. 3, the first region A1 is provided at an end on the first side surface 53 side from one end to the other end in the second direction Y of the light guide plate LG. The first area A1 is a light incident surface on which light emitted from the first light source LS1 is incident on the light guide plate LG. The fifth region A5 is provided at an end on the second side surface 54 side from the one end to the other end in the second direction Y of the light guide plate LG. The fifth area A5 is a light incident surface on which light emitted by the second light source LS2 is incident on the light guide plate LG. The second area A2, the third area A3, and the fourth area A4 are provided between the first area A1 and the fifth area A5 from one end to the other end in the second direction Y of the light guide plate LG. .

  The first area A1, the second area A2, the third area A3, the fourth area A4, and the fifth area A5 are arranged in this order along the first traveling direction DL1 '. As an example, in the first direction X, the width of the first area A1 is equal to the width of the fifth area A5, and the width of the second area A2 is equal to the width of the fourth area A4. Further, in the first direction X, the width of the third area A3 is smaller than the width of each of the areas A2 and A5. However, the widths of the regions A2, A4, A1, and A5 may be different, and the width of the third region A3 may be equal to or greater than the width of the regions A2 and A4.

  As shown in FIG. 4, the first area A1, the second area A2, the fourth area A4, and the fifth area A5 are inclined with respect to the first major surface 51. The second region A2 is parallel to the first major surface 51. Here, “parallel” means that the second area A2 is inclined to the first main surface 51 at an angle sufficiently smaller than the inclination angle of each of the areas A1, A2, A4 and A5 to the first main surface 51. (When substantially parallel to the first major surface 51).

  The second major surface 52 is provided with a plurality of prisms P. The plurality of prisms P includes a plurality of first prisms P1 in the second area A2, a plurality of second prisms P2 in the third area A3, and a plurality of third prisms P3 in the fourth area A4. . Each prism P1, P2, P3 extends in the second direction Y. The cross-sectional shape of the first prism P1 is, for example, uniform in the second direction Y, but may be different. The same applies to the second prism P2 and the third prism P3.

  For example, the first prism P1 and the second prism P2 have different shapes. The third prism P3 and the second prism P2 also have different shapes. The first prism P1 and the third prism P3 may have the same shape (including a symmetrical shape).

  For example, each first prism P1 and each second prism P2 are arranged at different densities. Further, the third prisms P3 and the second prisms P2 are also arranged at different densities. Each first prism P1 and each third prism P3 may be disposed at the same density.

  In a cross sectional view, a line connecting the vertices of the plurality of first prisms P1 is a first virtual line VL1, a line connecting the vertices of the plurality of second prisms P2 is a second virtual line VL2, and a vertex of the plurality of third prisms P3. The line connecting the two is called a third virtual line VL3. In the example of FIG. 4, each of the virtual lines VL1, VL2, and VL3 is a straight line. However, at least a part of each imaginary line VL1, VL2, and VL3 may be bent or curved.

  The first region A1 is inclined with respect to the first major surface 51 at a first angle θ1. The first virtual line VL1 is inclined with respect to the first major surface 51 at a second angle θ2. The third virtual line VL3 is inclined at a fourth angle θ4 with respect to the first major surface 51. The fifth region A5 is inclined at a fifth angle θ5 with respect to the first major surface 51. Each of the angles θ1, θ2, θ4, and θ5 is an acute angle. As an example, the first angle θ1 and the fifth angle θ5 are substantially equal (θ1 ≒ θ5), and the second angle θ2 and the fourth angle θ4 are substantially equal (θ2 ≒ θ4). As an example, the respective angles θ1 and θ5 are larger than the respective angles θ2 and θ4 (θ1 ≒ θ5> θ2 ≒ θ4). However, the first angle θ1 and the fifth angle θ5 may be different from the second angle θ2 and the fourth angle θ4 (θ1 ≠ θ5, θ2 ≠ θ4).

  The second virtual line VL2 is inclined with respect to each of the virtual lines VL1 and VL3. A third angle θ3 formed by the second virtual line VL2 and the first major surface 51 is smaller than the angles θ1, θ2, θ4, and θ5 (θ3 <θ1, θ2, θ4, and θ5). In the example of FIG. 4, the second virtual line VL <b> 2 is parallel to the first major surface 51. Here, “parallel” is the case where the second angle θ2 is zero, and the case where it is sufficiently smaller than the respective angles θ1, θ2, θ4, and θ5 (when substantially parallel to the first major surface 51). Including.

  Here, the thickness of the light guide plate LG in the first region A1 (the distance between the first region A1 and the first major surface 51) is D1, and the thickness of the light guide plate LG in the second region A2 (the second region A2 and the Distance to the 1st main surface 51 is D2, thickness of the light guide plate LG in the 3rd area A3 (distance between 3rd area A3 and 1st main surface 51) is D3, thickness of light guide plate LG in 4th area A4 (Distance between the fourth area A4 and the first main surface 51) is defined as D4, and thickness (distance between the fifth area A5 and the first main surface 51) in the fifth area A5 is defined as D5 . The distance D1 increases from the first side surface 53 toward the boundary between the areas A1 and A2. The distance D2 increases from the boundary of the regions A1 and A2 toward the boundary of the regions A2 and A3. The distance D5 increases from the second side surface 54 toward the boundary between the areas A4 and A5. The distance D4 increases from the boundary of the regions A4 and A5 toward the boundary of the regions A3 and A4. In the example of FIG. 4, the distance D3 is constant.

  In such a shape, the distance D3 is longer than the distance D1 at any position of the first area A1 (D3> D1) and longer than the distance D2 at any position of the second area A2 (D3> D2) . The distance D3 is longer than the distance D5 at any position of the fifth area A5 (D3> D5) and longer than the distance D4 at any position of the fourth area A4 (D3> D4).

FIG. 5 is a cross-sectional view showing the periphery of the first area A1 of the lighting device 3 in an enlarged manner. The relationship between the inclination angle of the light emitted from the first light source LS1 and the inclination angle θ1 of the first area A1 of the light guide plate LG will be described with reference to FIG. The first prism P1 of the light guide plate LG is omitted in FIG.
The intensity of light in the first irradiation direction DL1 emitted by the first light source LS1 is the highest at the first optical axis AX1, and the first optical axis AX1 is inclined at an angle に 対 し て with respect to the first major surface 51. Of the diffused light emitted by the first light source LS1, light that spreads most toward the first major surface 51 is incident on the first region A1 at the incident angle α and is refracted, and the first major surface 51 is refracted at the incident angle θ It is incident and reflected. Here, the angle Φ, the angle α, and the angle θ are all acute angles. The angle θ is preferably an angle greater than or equal to the total reflection critical angle θ _{r on} the first major surface 51. The total reflection critical angle θ _r is expressed by the following equation (1) from the refractive index n of the light guide plate LG and the refractive index 1 of air outside the light guide plate LG.
Equation (1): θ _r = sin ⁻¹ (1 / n)
From the above equation (1), the angle θ1, the angle α, and the refractive index n, the fact that the angle θ is an angle equal to or more than the total reflection critical angle θ _r is represented by the following equation (2).
Equation (2): θ = θ1 + sin ⁻¹ ((1 / n) sin α) ≧ θ _r
When equation (2) is solved for α, it is represented by the following equation (3).
Equation (3): α ≧ sin ⁻¹ (nsin (θ _r −θ1))

On the other hand, of the diffused light emitted by the first light source LS1, the light spreading to the far side from the first major surface 51 is inclined at an angle β with respect to the first major surface 51. The angle β and the angle θ1 preferably satisfy the following formula (4).
Formula (4): β <θ1

  When the relationship between the inclination angle of the light emitted by the first light source LS1 and the inclination angle θ1 of the first region A1 of the light guide plate LG satisfies the above formulas (2) to (4), the light emitted by the first light source LS1 is It is preferable because the light is efficiently propagated in the light guide plate LG. Also in the second light source LS2 and the fifth area A5, the relationship between the inclination angle of the light emitted by the second light source LS2 and the inclination angle θ5 of the fifth area A5 of the light guide plate LG is the equation (2) described above. It is preferable to have the structure which satisfies the formula similar to (4).

  FIG. 6 is an enlarged cross-sectional view of the first prism P1. The first prism P1 has a first inclined surface 11 and a second inclined surface 12, and has a triangular cross section. The angle of the apex angle formed by each of the inclined surfaces 11 and 12 is θa. An angle formed by the second major surface 52 and the first inclined surface 11 in the second region A2 is θb. An angle formed by the second major surface 52 and the second inclined surface 12 in the second region A2 is θc. The width of the first prism P1 in the first direction X is Dp1, and the distance between the adjacent first prisms P1 in the first direction X is Tp1. The height of the first prism P1 is H1.

  In the example of FIG. 6, the angle θa is an obtuse angle, the angles θb and θc are acute angles, and θa> θc> θb holds. As an example, the first inclined surface 11 is parallel to the first major surface 51. In this case, the angle θb is equal to the above-mentioned angle θ1. The shapes of all the first prisms P1 formed in the second area A2 may be the same, or the shapes of at least some of the first prisms P1 may be different.

The third prisms P3 formed in the fourth area A4 also have the same configuration as the first prism P1 described above.
The light emitted from the first major surface 51 can be increased as the area where the number of the first prism P1 and the number of the third prism P3 is large. Also, in general, the luminance of the exit surface tends to decrease at the end of the light guide plate. In view of these, as shown in FIG. 4, the density of the first prism P1 in the second region A2 may be increased from the boundary of the regions A2 and A3 toward the boundary of the regions A1 and A3. Similarly, the density of the third prism P3 in the fourth area A4 may be increased from the boundary of the areas A3 and A4 toward the boundary of the areas A4 and A5.

  Here, the density of the first prism P1 can be defined, for example, as the number of first prisms P1 per unit length. Alternatively, the density of the first prism P1 can also be represented by the ratio of the width Dp1 of the first prism P1 to the interval Tp1 of the adjacent first prism P1. The same applies to the density of the third prism P3.

Further, the angle θa and the height H1 of the apex angle of the first prism P1 may be increased from the boundary of the regions A2 and A3 toward the boundary of the regions A1 and A2. In this case, the density of the first prism P1 in the second area A2 may be constant.
Similarly, the angle and height of the apex angle of the third prism P3 may be increased from the boundary of the regions A3 and A4 toward the boundary of the regions A4 and A5. In this case, the density of the third prism P3 in the fourth area A4 may be constant.

  The adjustment of the density, the angle, and the height described above does not necessarily apply to all the first prisms P1 and the third prisms P3. For example, the density, angle, and height may be different in a portion of each first prism P1. Similarly, the density, angle, and height may be different in a portion of each third prism P3.

  FIG. 7 is an enlarged cross-sectional view of the second prism P2. The second prism P2 has a first inclined surface 21 and a second inclined surface 22 and has a triangular cross section. The angle of the apex angle formed by the inclined surfaces 21 and 22 is θd. An angle formed by the second major surface 52 and the first inclined surface 21 in the second region A2 is θe. An angle formed by the second major surface 52 and the second inclined surface 22 in the third region A3 is θf. The width of the second prism P2 in the first direction X is Dp2, and the distance between the adjacent second prisms P2 in the first direction X is Tp2. The height of the second prism P2 is H2.

  In the example of FIG. 7, the angle θd is an obtuse angle, the angles θe and θf are acute angles, and θd> θe and θf hold. The angle θe and the angle θf are, for example, the same angle (θe = θf). The angle θd and the height H2 of each second prism P2 formed in the third region A3 may be all the same or may be different in at least a part of each second prism P2. In addition, the density of each second prism P2 may be constant or may be different in at least a part of each second prism P2.

  Here, the density of the second prism P2 can be defined, for example, as the number of second prisms P2 per unit length. Alternatively, the density of the second prism P2 can also be represented by the ratio of the width Dp2 of the second prism P2 to the interval Tp2 of the adjacent second prism P2.

According to the structure of the light guide plate LG of the present embodiment, it is possible to suppress the luminance unevenness of the light emitted from the first major surface 51, and to irradiate the display panel 2 with the light having a favorable luminance distribution. Further, by arranging the first light source LS1 in the space below the light guide plate LG, it is possible to realize the miniaturization of the illumination device 3 to the display device 1 and the narrowing of the frame area. In addition, since the first irradiation direction DL1 and the second irradiation direction DX2 are inclined with respect to the first main surface 51, light is transmitted in the light guide plate LG as compared with the case where the first irradiation direction DL1 and the second irradiation direction DX2 are parallel It is hard to leak and can improve the utilization efficiency of light. The effects of the present embodiment will be described using FIG. 8 to FIG.
FIG. 8 is a view showing the luminance distribution of the exit surface of the light guide plate LGA according to the comparative example. The light guide plate LGA is a flat plate having a constant thickness from one end (left side in the drawing) to the other end (right side in the drawing) on the light source side. That is, the shape of the light guide plate LGA is a shape having the fourth area A4 in the light guide plate LG shown in FIG. 4 and not having the first area A1, the second area A2, the third area A3 and the fifth area A5. Equivalent to. Nine light sources are arranged along the left end in the figure. In this comparative example, the luminance of the exit surface increases with distance from the light source. In a region close to the light source, a stripe pattern in which high-brightness portions and low-brightness portions are repeated along the second direction Y is generated.

  FIG. 9 is a view showing the luminance distribution of the exit surface of the light guide plate LGB according to another comparative example. FIG. 10 is a schematic cross-sectional view of the light guide plate LGB. As shown in FIG. 10, the light guide plate LGB has a shape in which the thickness increases from the left end toward the center C in the first direction X, and the thickness decreases from the center C toward the right end. That is, the shape of the light guide plate LGB is a shape having the first area A1, the second area A2, the fourth area A4, and the fifth area A5 in the light guide plate LG shown in FIG. 4 and not having the third area A3. Equivalent to. A plurality of light sources LS are disposed to face each of the first area A1 and the fifth area A5. Although the same prism as the first prism P1 or the third prism P3 described above is disposed in the light guide plate LGB, it is omitted in FIG. There are five light sources at the left end and four at the right end.

  The light of the light source LS disposed at the left end of the light guide plate LGB is mainly reflected by the prism in the fourth area A4 and exits from the exit surface. In addition, the light of the light source LS disposed at the right end of the light guide plate LGB is mainly reflected by the prism in the second area A2 and exits from the exit surface. Therefore, as shown in FIG. 9, in this comparative example, the brightness reduction near the light source as shown in FIG. 8 does not occur. However, light reflected by the prism in the vicinity of the boundary between the regions A2 and A4 is difficult to emit from immediately above the vicinity of the boundary, and exits from a position distant from the vicinity of the boundary. Due to this, in the vicinity of the center C in the first direction X (near the boundary between the areas A2 and A4), the luminance of the emission surface is significantly reduced.

  FIG. 11 is a view showing the luminance distribution of the exit surface (first major surface 51) in the light guide plate LG according to the present embodiment. In the example of this figure, since the 2nd field A3 is provided between each field A2 and A4, the fall of the luminosity near the center has not arisen. That is, since the light from each of the light sources LS1 and LS2 is also emitted from the emission surface (first main surface 51) near the center by the second prism P2 of the third region A3, uneven brightness as shown in FIG. 9 is suppressed. ing.

According to the present embodiment described above, by providing the third region A3 in the light guide plate LG, it is possible to obtain a good luminance distribution of the first major surface 51. Moreover, the display quality of the display device 1 can be improved by using the lighting device 3 provided with such a light guide plate LG.
In addition, various suitable effects described above can be obtained from this embodiment.

Second Embodiment
The second embodiment will be described. The configurations and effects that are not particularly mentioned are the same as in FIG. 4 and the like of the first embodiment.
FIG. 12 is a view showing a schematic configuration of the illumination device 3 according to the second embodiment. The illumination device 3 includes a first reflection member 60 in addition to the first light source LS1, the second light source LS2, and the light guide plate LG. The first reflection member 60 is a sheet made of, for example, a metal material, and is opposed to the second major surface 52 of the light guide plate LG. The first reflection member 60 reflects the light leaked from the second major surface 52 of the light guide plate LG toward the light guide plate LG. The prism group on the second major surface 52 is omitted.

  The first reflection member 60 has a first portion 61 facing the second region A2, a second portion 62 facing the third region A3, and a third portion 63 facing the fourth region A4. . The first portion 61 is parallel to the second region A2, the second portion 62 is parallel to the third region A3, and the third portion 63 is parallel to the fourth region A4.

  As in the third embodiment shown in FIG. 12, even in the case where the first reflection member 60 is provided, it is possible to obtain a good luminance distribution as in the first embodiment. Furthermore, when the first reflection member 60 is provided, the light leaking from the second major surface 52 of the light guide plate LG can be reused, so that the brightness of the first major surface 51 can be entirely improved. The first portion 61, the second portion 62, and the third portion 63 may be formed non-parallel to the second region A2, the third region A3, and the fourth region A4, respectively.

Third Embodiment
A third embodiment will be described. The configurations and effects not particularly mentioned are similar to those of the above-described embodiments.
FIG. 13 is a schematic cross-sectional view of the lighting device 3 according to the third embodiment. The illumination device 3 includes a light guide plate LG, a first light source LS1, and a first reflection member 60. The lighting device 3 does not include the second light source LS2. The second major surface 52 of the light guide plate LG has a first area A1, a second area A2, and a third area A3. Although not shown here, a plurality of first prisms P1 are formed in the second area A2, and a plurality of second prisms P2 are formed in the third area A3.

  The distance D1 which is the thickness of the light guide plate LG in the first area A1 increases from the first side surface 53 toward the boundary between the areas A1 and A2. Similarly, the distance D2 which is the thickness of the light guide plate LG in the second area A2 increases from the boundary of the first area A1 and the second area A2 toward the boundary of the second area A2 and the third area A3. In the example of FIG. 13, the distance D3 which is the thickness of the light guide plate LG in the third region A3 is constant. As in the first embodiment, the distance D3 is longer than the distances D1 and D2 at any position of the first area A1 and the second area A2 (D3> D1 and D2).

  The first reflection member 60 has a first portion 61 facing the second region A2 and a second portion 62 facing the third region A3. The first portion 61 is parallel to the second region A2, and the second portion 62 is parallel to the third region A3. The first portion 61 and the second area A2 may not be parallel, and the second portion 62 and the third area A3 may not be parallel.

  The lighting device 3 further includes a second reflecting member 70. The second reflection member 70 is a sheet made of, for example, a metal material, and is opposed to the second side surface 54 of the light guide plate LG. The second reflective member 70 is parallel to the second side surface 54.

  In FIG. 13, an example of an optical path of light emitted by the first light source LS1 is indicated by a broken line. The light emitted from the first light source LS1 enters the light guide plate LG from the first area A1. When the second area A2 is inclined as shown in FIG. 13, this light is irradiated to the second area A2 at a shallow angle, so that the total reflection condition of each of the main surfaces 51 and 52 is not easily deviated. Therefore, the light propagates through the light guide plate LG while being reflected by the main surfaces 51 and 52 and reaches the second side surface 54. The light may exit from the second side surface 54, but is reflected by the second reflection member 70 and reenters the light guide plate LG. The light returned to the light guide plate LG is reflected by the first prism P1 of the first area A1 and the second prism P2 of the second area A2, and the total reflection condition of the first main surface 51 is deviated and the light is returned from the first main surface 51 I will emit.

  If the third region A3 is not provided, the light reflected by the second reflecting member 70 is emitted from the first major surface 51 in the vicinity of the first side surface 53 more, and the luminance unevenness is generated on the first major surface 51. Can occur. On the other hand, when the third area A3 is provided, it is possible to suppress such luminance unevenness as in the first embodiment and to improve the uniformity of the luminance distribution of the first major surface 51.

Fourth Embodiment
A fourth embodiment will be described. The configurations and effects not particularly mentioned are similar to those of the above-described embodiments.
FIG. 14 is a view showing a schematic cross section of a part of the illumination device 3 according to the fourth embodiment. The illumination device 3 includes a light guide plate LG, a first light source LS1, and a first reflection member 60. In FIG. 14, illustration of the prism P1 is omitted. As illustrated, the first region A1 of the second main surface 52 of the light guide plate LG is a curved surface that curves in a convex lens shape. The curved surface extends in parallel with the second direction Y, for example, in the cross-sectional shape illustrated. When the first area A1 is configured as described above, the first area A1 functions as a convex lens, whereby the diffusion angle of the light emitted from the first light source LS1 can be adjusted.

For example, when the first light source LS1 includes a plurality of light emitting elements that respectively emit light of different colors, the diffusion angles of light emitted from the respective light emitting elements may be different from each other. Also in that case, according to the diffusion angle of the light emitted from each light emitting element, adjusting the diffusion angle of the light emitted from each light emitting element by adjusting the curvature of the convex lens-like curved surface of the first region A1. it can. Therefore, color unevenness and luminance unevenness of the first major surface 51 can be suppressed more than in the first embodiment, and the uniformity of the luminance distribution of the first major surface 51 can be improved.
The same configuration as that of the first area A1 and the first light source LS1 disclosed in the present embodiment can be applied to the fifth area A5 and the second light source LS2.

Fifth Embodiment
A fifth embodiment will be described. The configurations and effects not particularly mentioned are similar to those of the above-described embodiments.
FIG. 15 is a view showing a schematic cross section of a part of the illumination device 3 according to the fifth embodiment. The illumination device 3 includes a light guide plate LG, a first light source LS1, and a first reflection member 60. The illustration of the prism P1 is omitted in FIG. The first light source LS1 includes a plurality of light emitting elements LS1-1 to LS1-3 that respectively emit light of different colors. The plurality of light emitting elements LS1-1, LS1-2, and LS1-3 respectively face the first area A1, and in this order from the first side surface 53 to the boundary between the first area A1 and the second area A2. It arranges along the inclined side of 1st area | region A1. A plurality of light emitting elements LS1-1 to LS1-3 are arranged in parallel with the second direction Y, for example, in the cross-sectional shape illustrated.

  In general, the shorter the wavelength of light, the larger the light absorption rate by the light guide plate LG. The wavelengths of red, green and blue light are blue <green <red. Therefore, the light absorption rate by the light guide plate LG is blue> green> red. In the shape of the light guide plate LG shown in FIG. 15, the length of the optical path passing through the light guide plate LG of the light emitted from each of the light emitting elements LS1-1 to LS1-3 is LS1-3 <LS1-2 <LS1-1. . Therefore, in consideration of the absorption of light by the light guide plate LG, it is preferable to arrange the light emitting element with a shorter wavelength of the emitted light in the second region A2 side in cross sectional view. That is, each light emitting element LS1-1, LS1-2, LS1-3 may be, for example, a red laser light source emitting red laser light, a green laser light source emitting green laser light, and a blue laser light source emitting blue laser light. preferable. When the outputs of the light emitting elements LS1-1 to LS1-3 are different, the one with the largest output is the light emitting element LS1-1, the one with the largest output is the light emitting element LS1-2, and the one with the smallest output is the one. Alternatively, the light emitting element LS1-3 may be used.

Even if it is the above composition, the same effect as each above-mentioned embodiment can be acquired. Further, as in the present embodiment, the color unevenness and the luminance unevenness of the first major surface 51 are further suppressed by changing the arrangement according to the characteristics of the light emitted from the light emitting elements LS1-1 to LS1-3. The uniformity of the luminance distribution of the first major surface 51 can be improved.
In FIG. 15, the number of the plurality of light emitting elements facing the first region A1 is not limited to three, and may be two or four, or five or more in cross section.
The same configuration as that of the first area A1 and the first light source LS1 disclosed in the present embodiment can be applied to the fifth area A5 and the second light source LS2.

Sixth Embodiment
A sixth embodiment will be described. The configurations and effects not particularly mentioned are similar to those of the above-described embodiments.
FIG. 16 is a view showing a schematic cross section of a part of the illumination device 3 according to the sixth embodiment. The illumination device 3 includes a light guide plate LG, a first light source LS1, and a first reflection member 60, and further includes a third reflection member 80 and a frame FM. In FIG. 16, illustration of the prism P1 is omitted. The frame FM is formed of, for example, a light shielding metal material. The frame FM encloses, for example, the first light source LS1, the light guide plate LG, the first light source LS1, and the back surface side (second main surface 52 side) of the first reflection member 60.

The third reflection member 80 is, for example, a mirror member. The first light source LS1 and the third reflecting member 80 overlap the first area A1 in the thickness direction of the light guide plate LG (third direction Z), and are disposed in the space surrounded by the light guide plate LG and the frame FM There is. The third reflection member 80 reflects the light emitted by the first light source LS1 and irradiates the first area A1 of the light guide plate LG.
In FIG. 16, an example of the optical path of the light emitted by the first light source LS1 is indicated by a broken line. The light emitted from the first light source LS1 is reflected by the third reflecting member 80, so that the light path is changed in the first irradiation direction DL1 and irradiated to the first area A1, and the respective main surfaces 51 of the light guide plate LG , 52 and propagates through the light guide plate LG.

  Even if it is the above composition, the same effect as each above-mentioned embodiment can be acquired. Further, by using the third reflection member 80 as in the present embodiment, there is no need to incline the first light source LS1 in the first irradiation direction DL1, and by adjusting the angle of the first reflection member MR1, the first light source LS1 can be used. The irradiation direction of the light irradiated to the area A1 can be easily adjusted. Moreover, the freedom degree of the arrangement position of 1st light source LS1 increases by using the 3rd reflective member 80 like this embodiment. Further, in the example of FIG. 10, since the first light source LS1 is disposed in contact with the frame FM, heat radiation from the first light source LS1 becomes easier.

The third reflection member 80 may have a structure in which the light from the first light source LS1 is reflected only once and irradiated to the first area A1, or it may be reflected twice or more and irradiated to the first area AR1. The structure may be
Moreover, the illuminating device 3 may be provided with the condensing lens which is opposingly arranged by 1st light source LS1, and adjusts the diffusion angle of the light which 1st light source LS1 emits. By using a condensing lens, the light emitted by the first light source LS1 can be accurately irradiated to the third reflecting member 80.
The configuration described in the vicinity of the first light source LS1 in this embodiment can be similarly applied to the side of the second light source LS2.

Seventh Embodiment
A seventh embodiment will be described. The configurations and effects not particularly mentioned are similar to those of the above-described embodiments.
FIG. 17 is a view showing a schematic cross section of a part of the illumination device 3 according to the seventh embodiment. The illumination device 3 includes a light guide plate LG, a first light source LS1, a first reflection member 60, and a frame FM, and further includes a bending member 90.

  The first light source LS1 overlaps the second region A2 in the thickness direction (third direction Z) of the light guide plate LG. The bending member 90 partially overlaps the first region A1 in the thickness direction (third direction Z) of the light guide plate LG. The first light source LS1 and the bending member 90 are disposed in a space surrounded by the light guide plate LG and the frame FM. The bending member 90 shown in FIG. 17 is a prism having a triangular shape in the XZ cross section and extending in the second direction Y. Specifically, the bending member 90 has a first surface 91, a second surface 92, and a third surface 93. As an example, one bending member 90 may be provided for each of the plurality of first light sources LS1 aligned in the second direction Y as shown in FIG. Further, one bending member 90 may be provided for each of the two or more first light sources LS1, or one bending member may be provided for all the first light sources LS1.

  The first surface 91 has an incident area 91a and an outgoing area 91b. The incident area 91a is opposed to the first light source LS1. The emission area 91b is opposed to the first area A1 of the light guide plate LG. In the example of FIG. 17, the first surface 91 is inclined with respect to the third direction Z. The second surface 92 and the third surface 93 are inclined at a predetermined angle with respect to the first surface 91. The angle formed by the second surface 92 and the first surface 91 and the angle formed by the third surface 93 and the first surface 91 may be the same or different.

  The light emitted from the first light source LS1 is incident on the bending member 90 from the incident area 91a. The incident light is reflected by the second surface 92, and further reflected by the third surface 93, and exits from the exit area 91b. The emitted light is irradiated to the first side surface 53 of the light guide plate LG along the first irradiation direction DL1 and propagates through the light guide plate LG while being reflected by the main surfaces 51 and 52 of the light guide plate LG. As described above, in the present embodiment, the optical path of the light emitted from the first light source LS1 is bent in the first irradiation direction DL1 by the bending member 90, and is incident on the light guide plate LG.

Even if it is the above composition, the same effect as each above-mentioned embodiment can be acquired. In this configuration, by using the bending member 90 as in the present embodiment, it is possible to obtain the same effect as that of the sixth embodiment.
The configuration described in the vicinity of the first light source LS1 in this embodiment can be similarly applied to the side of the second light source LS2.

Eighth Embodiment
An eighth embodiment will be described. The configurations and effects not particularly mentioned are similar to those of the above-described embodiments.
FIG. 18 is a schematic cross-sectional view of a lighting device 3 ′ according to the eighth embodiment. The illumination device 3 'includes three illumination devices 3 shown in FIG. 12 in a cross sectional view, and the plurality of illumination devices 3 are arranged adjacent to each other in the first direction X. The LG1 to LG3 provided in the three lighting devices 3 have the same structure as the LG provided in the lighting device 3 shown in FIG. The illumination device 3 ′ is configured, for example, by arranging the illumination devices 3 having the cross-sectional shape shown in the drawing, adjacent to each other in the second direction Y.

  Even if it is the above composition, the same effect as each above-mentioned embodiment can be acquired. In addition, by arranging a plurality of small lighting devices 3 adjacent to each other, a large lighting device 3 ′ can be configured without increasing the thickness of the lighting device 3 ′. Further, in the lighting device 3 ′ having such a configuration, the contrast ratio can be improved and power saving can be achieved by partially driving the lighting device 3. Further, in the lighting device 3 ′, the light can be bent at the boundary portion of the adjacent lighting devices 3, and the freedom of the shape is improved.

  Note that FIG. 18 shows an example in which three illumination devices 3 are disposed adjacent to each other in the first direction X1 in a cross sectional view, but the present invention is not limited to this, and two or four may be provided. Five or more may be sufficient. Further, the plurality of lighting devices 3 constituting the lighting device 3 'are not limited to the lighting device 3 shown in FIG. 12, and any of the lighting devices 3 according to the above-described embodiments may be used. The lighting device 3 according to the present invention may be used.

[Ninth embodiment]
A ninth embodiment will be described. The configurations and effects not particularly mentioned are similar to those of the above-described embodiments.
FIG. 19 is a schematic cross-sectional view of a portion of a lighting device according to a ninth embodiment. The illumination device 3 shown in FIG. 19 is a modified example of the illumination device 3 ′ shown in FIG. 18 and is an enlarged view of a boundary portion between the two light guide plates LG1 and LG2. The illumination device 3 'shown in FIG. 19 does not include the second light source LS2, but includes the fourth reflection member 100, as compared to the illumination device 3' shown in FIG.

  The first light source LS1 and the fourth reflection member 100 are disposed on the boundary between the two light guide plates LG1 and LG2 in the thickness direction (third direction Z) of the light guide plate LG. The fourth reflective member 100 shown in FIG. 17 is a mirror member which is V-shaped in the X-Z cross section and extends in the second direction Y. Specifically, the fourth reflection member 100 has a first surface 101 and a second surface 102. As an example, one fourth reflection member 100 may be provided for each of the plurality of first light sources LS1 aligned in the second direction Y. In addition, one fourth reflection member 100 may be provided for each of two or more first light sources LS1, or one fourth reflection member 100 may be provided for all the first light sources LS1.

  In the example of FIG. 19, the first surface 101 is inclined at a predetermined angle with respect to the third direction Z, and faces the fifth area A5 of one of the light guide plates LG1. The second surface 102 is inclined at a predetermined angle with respect to the third direction Z, and faces the first region A1 of the other light guide plate LG2. The first surface 91 and the second surface 92 also face the first light source LS1.

  In FIG. 19, an example of an optical path of light emitted by the first light source is indicated by a broken line. The light emitted from the first light source LS1 is emitted in the third direction Z in the illustrated example, and is reflected by the first surface 91 and the second surface 92 of the fourth reflecting member 100. The light reflected by the first surface 101 and deflected in the second irradiation direction DL2 is irradiated to the fifth region A5 of one light guide plate LG1, and is reflected by the main surfaces 51 and 52 of the light guide plate LG1. While propagating through the light guide plate LG1. On the other hand, the light reflected by the second surface and deflected in the first irradiation direction DL1 is irradiated to the first area A1 of the other light guide plate LG2, and reflected by the main surfaces 51 and 52 of the light guide plate LG. While propagating through the light guide plate LG2.

  Even if it is the above composition, the same effect as each above-mentioned embodiment can be acquired. In this configuration, the number of light sources LS1 and LS2 can be reduced compared to the above-described embodiments. The plurality of lighting devices 3 constituting the lighting device 3 ′ are not limited to the lighting device 3 shown in FIG. 12, and any of the lighting devices according to the above-described embodiments may be used. For example, when two lighting devices 3 having the same configuration as the lighting device 3 shown in FIG. 13 are adjacent to each other, the first side surfaces 53 of the light guide plate LG are adjacent to each other to face each other, instead of the two first light sources LS1. Alternatively, one first light source LS1 and a fourth reflecting member 100 may be provided.

  As described above, based on the lighting device and the display device described as the embodiments of the present invention, all the lighting devices and the display devices which can be appropriately designed and implemented by those skilled in the art are also included in the present invention. It belongs to the scope of the invention.

  Within the scope of the concept of the present invention, those skilled in the art can conceive of various modifications, which are considered to be within the scope of the present invention. For example, those in which a person skilled in the art appropriately adds, deletes, or changes the design of the components or adds, omits, or changes the steps of the above-described embodiments may be included in the present invention. As long as it comprises the gist, it is included in the scope of the present invention.

  In addition, with regard to the other effects brought about by the aspects described in each embodiment, what is apparent from the description of the present specification or that which can be appropriately conceived by those skilled in the art is naturally solved as the present invention. Be done.

  DESCRIPTION OF SYMBOLS 1 ... Display apparatus, 2 ... Display panel, 3 ... Lighting apparatus, SUB1 ... 1st board | substrate, SUB2 ... 2nd board | substrate, LC ... Liquid crystal layer, DA ... Display area, LG ... Light guide plate, PS ... Prism sheet, DS ... Diffusion Sheet 51: first main surface 52: second main surface 53: first side 54: second side A1 to A3 first to third regions P1 to P3 first to third prisms LS1 first light source LS2 second light source VL1 to VL3 first to third virtual lines 60 first reflecting member 61 to 63 first to third portions 70 second reflecting member FM ... frame, 80 ... third reflecting member, 90 ... bending member, 100 ... fourth reflecting member

Claims (12)

A light guide plate having a first main surface and a second main surface opposite to the first main surface and including a plurality of surfaces;
A first light source for emitting a laser beam along a first irradiation direction;
A plurality of prisms provided on the second main surface;
Equipped with
The laser beam travels in a first traveling direction in plan view,
The second main surface has a first region and a second region arranged in order along the first traveling direction,
The light emitted by the first light source is incident on the first area,
The plurality of prisms includes a plurality of first prisms in the second region, and
In the cross sectional view, the distance to the first major surface is longer in the order of the first region and the second region,
The first irradiation direction is inclined with respect to the first main surface,
Lighting device. At least a part of the first light source overlaps the first area or the second area in a plan view.
The lighting device according to claim 1. Further comprising a first reflecting member,
The light emitted from the first light source is reflected by the first reflecting member, so that the light path is deflected in the first irradiation direction and the first area is irradiated.
The lighting device according to claim 1. In a sectional view, the first region is inclined relative to the first major surface with respect to a first imaginary line connecting apexes of the plurality of first prisms.
The illuminating device of any one of Claim 1 to 3. The first light source comprises a plurality of light emitting elements,
In the cross sectional view, the plurality of light emitting elements are arranged along the inclined side of the first region,
The lighting device according to any one of claims 1 to 4. The plurality of light emitting elements emit light of different wavelengths,
In the cross sectional view, the plurality of light emitting elements are arranged closer to the second region as the wavelength of light emitted is shorter.
The lighting device according to claim 5. The first region is convexly curved,
The lighting device according to any one of claims 1 to 6. The second main surface includes the first region, the second region, and the third region arranged in order along the first traveling direction.
The plurality of prisms includes a plurality of second prisms in the third region,
In the cross sectional view, the distance to the first major surface is longer in the order of the first region, the second region, and the third region,
The lighting device according to any one of claims 1 to 7. A second imaginary line connecting vertices of the plurality of second prisms is inclined with respect to a first imaginary line connecting vertices of the plurality of first prisms.
The lighting device according to claim 8. A second reflection member facing the second main surface,
The second reflection member includes a first portion facing the second region and a second portion facing the third region.
The illuminating device of Claim 8 or 9. The second main surface includes the first region, the second region, the third region, the fourth region, and the fifth region, which are arranged in order along the first traveling direction.
The light guide plate may further include a second light source that emits light to the fifth area of the light guide plate.
The plurality of prisms includes a plurality of third prisms in the fourth region,
In the cross sectional view, the fifth area and a third imaginary line connecting the apexes of the plurality of third prisms of the fourth area are inclined with respect to the first main surface,
In the cross sectional view, the distance to the first major surface is longer in the order of the fifth region, the fourth region, and the third region,
The lighting device according to any one of claims 8 to 10. A plurality of lighting devices according to any one of claims 1 to 11,
The plurality of lighting devices are disposed adjacent to each other in a plan view.
Lighting device.

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