Luminaire and display device

Abstract

To limit an emission angle range regarding a part of emission light.SOLUTION: A luminaire 12 includes: a first light source 26; a first light guide plate 27 having a first main surface 27B and a second main surface 27C; a second light source 20; a second light guide plate 21 having a third main surface 21B and a fourth main surface 21C; a third light source 13; an optical member 14 having a light incident surface 14A and a fifth main surface 14B; and a first sheet 18. In the first light guide plate 27 and the second light guide plate 21, the main surfaces are overlapped with each other, and they are disposed on the opposite side from a diffusion plate side with respect to the first sheet 18. The first sheet 18 has two first light shielding parts 18C and two first light transmission parts 18D. On the first opposite main surface 27C, a first light reflection part 35 is provided, and on the second opposite main surface 21C, a second light reflection part 36 is provided. The first light reflection part 35 is selectively provided in a first region A1 on the first opposite main surface 27C. The second light reflection part 36 is provided at least in a fourth region A4 on the second opposite main surface 21C.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a lighting device and a display device. [Background technology]

[0002] Conventionally, an example of a lighting device is known, which is described in Patent Document 1 below. The lighting device described in Patent Document 1 operates in at least two operation modes, namely, a free-view mode and a limited-view mode. The lighting device includes a backlight system. A light guide plate is disposed in front of the backlight system, and a light source is disposed along the side of the light guide plate. The light guide plate has a resin matrix in which diffusing particles made of a polymer are dispersed, and has a light transmittance of at least 80%. In the free-view mode, the backlight system is turned on and the light source is turned off. In the limited-view mode, the light source is turned on and the backlight system is turned off. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2017 / 0069236 Summary of the Invention [Problem to be solved by the invention]

[0004] In the lighting device described in the above-mentioned Patent Document 1, the emission angle range of all emitted light is limited in the limited field of view mode, and the emission angle range of all emitted light is not limited in the free field of view mode. However, Patent Document 1 has a problem in that it cannot handle cases where it is required to limit the emission angle range for part of the emitted light and not limit the emission angle range for the rest of the emitted light.

[0005] The technology described in this specification was developed based on the above circumstances, and aims to limit the emission angle range for a portion of the emitted light. [Means for solving the problem]

[0006] (1) A lighting device according to the technology described in this specification includes a first light source, a first light guide plate having at least a part of an outer peripheral end face that faces the first light source and is a first end face through which light is incident, one main face being a first main face for emitting light, and the other main face being a second main face, and a second light source, and at least a part of an outer peripheral end face that faces the second light source and is a second end face through which light is incident, one main face being a third main face for emitting light, and the other main face being a second main face. a second light guide plate having a fourth main surface as a fourth main surface, a third light source, an optical member having a light incident surface facing the third light source and into which light is incident, and a fifth main surface from which light is emitted, and a first sheet having one main surface as a sixth main surface and the other main surface as a seventh main surface arranged facing the fifth main surface, wherein the first light guide plate and the second light guide plate have their main surfaces overlapping each other and are arranged on the opposite side of the first sheet to the optical member side. the first sheet has at least two first light-shielding portions that are spaced apart in a first direction including a direction from the first light source to the first light guide plate and block light, and a first light-transmitting portion that is arranged between the two first light-shielding portions and transmits light, the second main surface is provided with a first light-reflecting portion that reflects light to promote light emission from the first main surface, and the fourth main surface is provided with a second light-reflecting portion that reflects light to promote light emission from the third main surface, when the second main surface is divided into a first region and a second region adjacent to the first region in the first direction, the first light-reflecting portion is selectively provided in the first region on the second main surface, and when the fourth main surface is divided into a third region overlapping with the first region and a fourth region overlapping with the second region, the second light-reflecting portion is provided in at least the fourth region on the fourth main surface.

[0007] (2) In addition to the above-mentioned (1), in the lighting device, the second light reflecting portion may be provided across the third region and the fourth region on the fourth main surface.

[0008] (3) In addition to the above-mentioned (2), in the above lighting device, the first light reflecting portion may be composed of a plurality of first lenses arranged in a line along the first direction on the second principal surface, and the second light reflecting portion may be composed of a plurality of second lenses arranged in a line along the first direction on the fourth principal surface, and among the plurality of second lenses, at least the second lens arranged in the fourth region may have a first inclined surface that is inclined rising from an opposite side to the second light source in the first direction toward the second light source.

[0009] (4) In addition to the above (3), the lighting device may further include a second inclined surface, of the plurality of second lenses, that is arranged in the third region and that has an inclination that rises from a side opposite the second light source in the first direction toward the second light source.

[0010] (5) In addition to the above-mentioned (4), in the lighting device, the first inclined surface and the second inclined surface may have an equal inclination angle with respect to the first direction.

[0011] (6) In addition to any one of (3) to (5), the lighting device may further include a third inclined surface that is inclined from a side opposite to the first light source in the first direction toward the first light source, and a positional relationship of the first light source with respect to the first light guide plate in the first direction is the same as a positional relationship of the second light source with respect to the second light guide plate in the first direction, and the first lenses may each have a third inclined surface that is inclined from a side opposite to the first light source in the first direction toward the first light source.

[0012] (7) Furthermore, in addition to any one of (2) to (6), the lighting device may further include a light source control unit that controls driving of the first light source, the second light source, and the third light source, and the light source control unit may switch between a first mode in which the first light source and the third light source are turned on and the second light source is turned off, and a second mode in which the second light source and the third light source are turned on and the first light source is turned off, based on an input of a switching signal.

[0013] (8) In addition to any one of (2) to (7), the lighting device may be arranged such that the second light guide plate is disposed with the first light guide plate sandwiched between the second light guide plate and the first sheet.

[0014] (9) In addition to any one of (2) to (7) above, the lighting device may be arranged such that the first light guide plate is disposed with the second light guide plate sandwiched between the first sheet and the first light guide plate.

[0015] (10) In addition to any one of (1) to (9) above, the lighting device may further comprise a third light guide plate, the light incident surface of which is formed by at least a portion of an outer peripheral end surface, and the light incident surface of which is arranged opposite the third light source.

[0016] (11) In addition to the above (10), the lighting device may further include a light source control unit that controls driving of the first light source, the second light source, and the third light source, the light incident surface being formed of a portion of the outer peripheral end face of the third light guide plate that extends along the first direction, and a plurality of the third light sources being arranged side by side along the first direction, the plurality of third light sources including a fourth light source arranged opposite a portion of the third light guide plate that overlaps with the first region and the third region, and a fifth light source arranged opposite a portion of the third light guide plate that overlaps with the second region and the fourth region, and the light source control unit may cause an amount of light emitted per unit time of the fourth light source to be greater than an amount of light emitted per unit time of the fifth light source.

[0017] (12) In addition to any one of (1) to (9), the lighting device may further include a light source control unit that controls driving of the first light source, the second light source, and the third light source, wherein a plurality of the third light sources are arranged in a plane so as to overlap with the fifth principal surface, and the optical element has a light incident surface that is formed by a principal surface opposite to the fifth principal surface, and the light incident surface is arranged opposite the plurality of third light sources.

[0018] (13) In addition to the above (12), the lighting device may further include a fourth light source arranged to overlap the first region and the third region, and a fifth light source arranged to overlap the second region and the fourth region, and the light source control unit may set the amount of light emitted per unit time of the fourth light source to be greater than the amount of light emitted per unit time of the fifth light source.

[0019] (14) Furthermore, in addition to any one of (1) to (13), the lighting device may further include a second sheet having one principal surface serving as an eighth principal surface and the other principal surface serving as a ninth principal surface facing the first principal surface, the second sheet having at least two second light-shielding portions spaced apart in the first direction to block light, and a second light-transmitting portion disposed between the two second light-shielding portions to transmit light.

[0020] (15) A display device related to the technology described in this specification includes an illumination device described in any one of (1) to (14) above, and a display panel that performs display using light from the illumination device. Effect of the Invention

[0021] According to the technology described in this specification, it is possible to limit the output angle range for a portion of the output light. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a side cross-sectional view of a liquid crystal display device according to a first embodiment. [Diagram 2] 2 is a cross-sectional view of the liquid crystal display device according to the first embodiment taken along line ii-ii in FIG. [Diagram 3] FIG. 1 is a plan view of a backlight device provided in a liquid crystal display device according to a first embodiment. [Figure 4] 3 is a cross-sectional view of the backlight device according to the first embodiment taken along the same cutting line as FIG. 2 . [Diagram 5] 2 is a cross-sectional view of the backlight device according to the first embodiment taken along the same cutting line as FIG. 1 . [Figure 6]FIG. 4 is a perspective view of a third light guide plate constituting the backlight device according to the first embodiment, viewed from the third opposite principal surface side. [Figure 7] FIG. 11 is a bottom view showing the configuration of the third opposite principal surface of the third light guide plate according to the first embodiment. [Figure 8] FIG. 1 is a side cross-sectional view of a second light guide plate constituting a backlight device according to a first embodiment. [Figure 9] FIG. 1 is a bottom view showing a configuration of a second opposite principal surface of a second light guide plate according to a first embodiment; [Figure 10] 2 is a cross-sectional view of the liquid crystal display device according to the first embodiment taken along line xx in FIG. [Figure 11] 11 is a cross-sectional view of the backlight device according to the first embodiment taken along the same line as FIG. 10 . [Figure 12] FIG. 1 is a block diagram showing an electrical configuration of a liquid crystal display device according to a first embodiment. [Figure 13] 1 is a graph showing experimental results of a demonstration experiment 1 according to the first embodiment, illustrating a light distribution in the second display mode or a light distribution of emitted light from a portion of the backlight device that overlaps with the first region and the third region in the first display mode. [Figure 14] 10 is a graph showing experimental results of a demonstration experiment 1 according to the first embodiment, illustrating a light distribution of emitted light from a portion of the backlight device that overlaps with the second region and the fourth region in a first display mode. [Figure 15] FIG. 1 is a diagram for explaining a light blocking range and a visible range of a first display unit and a second display unit in a liquid crystal display device installed in a passenger vehicle according to embodiment 1. [Figure 16] FIG. 11 is a diagram showing a luminance distribution, which is an experimental result obtained when the luminance of light emitted from the backlight device at an angle of 0° in the second display mode in the demonstration experiment 2 according to the first embodiment is measured. [Figure 17] 13 is a graph showing a luminance distribution, which is an experimental result obtained when the luminance of light emitted from the backlight device at an angle of 0° in the second display mode in the demonstration experiment 2 according to the first embodiment is measured. [Figure 18] FIG. 11 is a diagram showing a luminance distribution, which is an experimental result obtained when the luminance of light emitted from the backlight device at an angle of −45° in the second display mode in the demonstration experiment 2 according to the first embodiment is measured. [Figure 19] 13 is a graph showing a luminance distribution, which is an experimental result obtained when measuring the luminance of light emitted from the backlight device at an angle of −45° in the second display mode in the demonstration experiment 2 according to the first embodiment. [Figure 20] FIG. 11 is a diagram showing a luminance distribution obtained as a result of an experiment in which the luminance of light emitted from the backlight device at an angle of 0° in the first display mode was measured in a demonstration experiment in accordance with the first embodiment. [Figure 21] 13 is a graph showing a luminance distribution obtained as a result of an experiment in which the luminance of light emitted from the backlight device at an angle of 0° in the first display mode was measured in a verification experiment 2 according to the first embodiment. [Figure 22] FIG. 11 is a diagram showing a luminance distribution, which is an experimental result obtained when the luminance of light emitted from the backlight device at an angle of −45° in the first display mode was measured in the demonstration experiment 2 according to the first embodiment. [Figure 23] 13 is a graph showing a luminance distribution obtained as a result of an experiment in which the luminance of light emitted from the backlight device at an angle of −45° in the first display mode was measured in the demonstration experiment 2 according to the first embodiment. [Figure 24] 1 is a cross-sectional view of a liquid crystal display device according to a second embodiment of the present invention taken along the same line as FIG. [Diagram 25] 1 is a cross-sectional view of a backlight device according to a second embodiment taken along the same line as FIG. [Figure 26] 1 is a cross-sectional view of a liquid crystal display device according to a third embodiment of the present invention taken along the same line as FIG. [Figure 27] FIG. 11 is a plan view showing an LED substrate constituting a backlight device according to a third embodiment. [Figure 28] 1 is a cross-sectional view of a liquid crystal display device according to a fourth embodiment taken along the same line as FIG. [Figure 29] 1 is a cross-sectional view of a liquid crystal display device according to a fifth embodiment of the present invention taken along the same line as FIG. [Diagram 30] 13 is a side cross-sectional view of a liquid crystal display device according to embodiment 6. [Diagram 31] 30 in a backlight device according to a sixth embodiment. [Diagram 32]1 is a cross-sectional view of a liquid crystal display device according to another embodiment (1) taken along the same line as FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] <Embodiment 1> The first embodiment will be described with reference to Fig. 1 to Fig. 23. In this embodiment, a liquid crystal display device (display device) 10 is illustrated. Note that the X-axis, Y-axis, and Z-axis are shown in a part of each drawing, and each axis direction is drawn to be the direction shown in each drawing. Also, the up-down direction is based on Fig. 1, Fig. 2, Fig. 4, Fig. 5, Fig. 8, Fig. 10, and Fig. 11, and the upper side of each drawing is the front side and the lower side of each drawing is the back side.

[0024] In this embodiment, as shown in FIG. 1, an in-vehicle liquid crystal display device 10 is illustrated. The in-vehicle liquid crystal display device 10 is generally installed in, for example, a car navigation system that displays a map as an image, a multifunction display that displays the operating status of an air conditioner and other devices in addition to a map as an image, an instrument panel that displays gauges and warnings as an image, an infotainment system that displays a TV image and audio information in addition to a map as an image, and has a horizontally long shape. The liquid crystal display device 10 according to this embodiment has a length close to the width of the vehicle in the passenger compartment from in front of the passenger seat to in front of the driver's seat. Note that the passenger car in which the liquid crystal display device 10 according to this embodiment is installed has a configuration in which the driver's seat is located on the left side of FIG. 1 and the passenger seat is located on the right side of FIG. 1, that is, it is a left-hand drive vehicle. In this embodiment, the liquid crystal display device 10 is installed in a position in which the X-axis direction is approximately the same as the horizontal direction and the Y-axis direction is parallel to the vertical direction.

[0025] The liquid crystal display device 10 has a horizontally long shape as a whole, and as shown in Figs. 1 to 3, the short side direction coincides with the Y-axis direction, the long side direction coincides with the X-axis direction, and the plate thickness direction coincides with the Z-axis direction. As shown in Figs. 1 and 2, the liquid crystal display device 10 includes a liquid crystal panel (display panel) 11 that displays an image, and a backlight device (illumination device) 12 that is disposed on the rear side of the liquid crystal panel 11 and irradiates light used for display toward the liquid crystal panel 11. First, the configuration of the liquid crystal panel 11 will be described. The liquid crystal panel 11 has a plate-like main surface parallel to the X-axis direction and the Y-axis direction, and the normal direction (thickness direction) of the main surface coincides with the Z-axis direction. The central part of the main surface of the liquid crystal panel 11 is a display area AA capable of displaying an image, and a frame-like peripheral end side part surrounding the display area AA is a non-display area NAA. As shown in Fig. 1, the display area AA is divided into a first display section AA1 located on one side (left side in Fig. 1) in the X-axis direction (longer side direction of the liquid crystal panel 11) and a second display section AA2 located on the other side (right side in Fig. 1) in the X-axis direction. The first display section AA1 is located in front of the driver's seat inside the vehicle cabin. The second display section AA2 is located in front of the passenger seat inside the vehicle cabin. The area ratio between the first display section AA1 and the second display section AA2 is, for example, 1:1.

[0026] The liquid crystal panel 11, like the liquid crystal display device 10, has a horizontally long, elongated shape as a whole, and includes a pair of substrates and a liquid crystal layer sealed between the pair of substrates. Of the pair of substrates constituting the liquid crystal panel 11, the one disposed on the front side is a CF substrate (opposing substrate), and the one disposed on the back side is an array substrate (TFT substrate). The CF substrate is provided with color filters exhibiting R (red), G (green), B (blue), and the like, and a light-shielding portion (black matrix) that separates adjacent color filters. The array substrate (TFT substrate) is provided with at least gate wiring and source wiring that are perpendicular to each other, switching elements (e.g., TFTs) connected to the gate wiring and source wiring, and pixel electrodes that are connected to the switching elements and form pixels. Note that an alignment film is provided on each inner surface of the array substrate and the CF substrate that form the liquid crystal panel 11. Also, a polarizing plate is attached to each outer surface of the array substrate and the CF substrate that form the liquid crystal panel 11.

[0027] As described above, the in-vehicle liquid crystal display device 10 according to this embodiment has a length close to the vehicle width, and accordingly, the display area AA of the liquid crystal panel 11 includes a first display unit AA1 located in front of the driver's seat and a second display unit AA2 located in front of the passenger seat. Therefore, for example, while the passenger seat is moving, it is required to limit the viewing angle so that the display images of the first display unit AA1 and the second display unit AA2 are visible from the passenger seat, while the display image of the first display unit AA1 is visible from the driver's seat but the display image of the second display unit AA2 is not visible. On the other hand, for example, while the passenger seat is stopped, it is required not to limit the viewing angle so that the display images of the first display unit AA1 and the second display unit AA2 are visible from both the passenger seat and the driver's seat.

[0028] In response to such demands, the backlight device 12 according to the present embodiment includes a diffusion sheet 12S, a second backlight unit 12U2 arranged on the back side of the diffusion sheet 12S, a first backlight unit 12U1 arranged on the back side of the second backlight unit 12U2, and a third backlight unit 12U3 arranged on the back side of the first backlight unit 12U1, as shown in Figs. 1 and 2. The diffusion sheet 12S is located on the light output side (the side closest to the liquid crystal panel 11) of the backlight device 12, and diffuses light incident from the back side and outputs the light toward the liquid crystal panel 11. In this embodiment, the first backlight unit 12U1, the second backlight unit 12U2, and the third backlight unit 12U3 are all so-called edge light types. The backlight device 12 is generally long horizontally, similar to the liquid crystal display device 10.

[0029] First, the configuration of the third backlight unit 12U3 will be described. As shown in Fig. 1 and Fig. 2, the third backlight unit 12U3 includes at least a third LED (third light source) 13, a third light guide plate (optical member) 14 that guides light from the third LED 13, a reflection sheet 15 arranged on the back side (opposite light output side) of the third light guide plate 14, a first prism sheet 16 arranged on the front side (light output side) of the third light guide plate 14, a second prism sheet 17 arranged on the front side of the first prism sheet 16, and a first louver (first sheet) 18 arranged on the front side of the second prism sheet 17.

[0030] As shown in FIG. 2, the third LED 13 is substantially block-shaped, and one of a pair of surfaces along the X-axis direction and the Z-axis direction is a third light-emitting surface 13A that emits light. As shown in FIG. 3, the third LED 13 is arranged in a row at intervals along the X-axis direction (a first direction described later). The third LED 13 is mounted on an LED board. The third LED 13 is configured by sealing an LED chip on a board portion mounted on the LED board with a sealing material. The LED chip provided in the third LED 13 emits a single color light, for example, blue light. A phosphor is dispersed and blended in the sealing material provided in the third LED 13. The phosphor contained in the sealing material includes a yellow phosphor, a green phosphor, a red phosphor, and the like. The third LED 13 provided with such an LED chip and sealing material emits white light as a whole.

[0031] The third light guide plate 14 is made of a synthetic resin material (e.g., acrylic resin such as PMMA) that has a refractive index sufficiently higher than that of air and is almost transparent. As shown in Figs. 1 and 2, the third light guide plate 14 has a plate shape with a main surface parallel to the main surface of the liquid crystal panel 11. The main surface of the third light guide plate 14 is parallel to the X-axis direction and the Y-axis direction, and the normal direction (thickness direction) of the main surface coincides with the Z-axis direction. The third light guide plate 14 is arranged so as to overlap at least the entire display area AA in a plan view. The third light guide plate 14 is arranged in line with the third LED 13 along the Y-axis direction, and is arranged in line with the liquid crystal panel 11 and each prism sheet 16, 17, etc. along the Z-axis direction. As shown in Figs. 2 and 3, the third light guide plate 14 is arranged on one side (upper side in Fig. 3) of the third LED 13 in the Y-axis direction. The third light guide plate 14 has one end surface (part) of its outer peripheral end surface extending along the X-axis direction (first direction) as a third light incident end surface (light entrance surface) 14A facing the third light emitting surface 13A of the third LED 13. The third light incident end surface 14A is a surface parallel to the third light emitting surface 13A of the third LED 13, and the light emitted from the third light emitting surface 13A is incident on the third light guide plate 14. In this way, the third LED 13 is arranged only on one side in the Y-axis direction. Therefore, the third backlight unit 12U3 is an edge light type with light entering from one side.

[0032] Of the pair of main surfaces in the third light guide plate 14, the front main surface facing the first prism sheet 16 is the third light guide plate light output main surface (fifth main surface) 14B that outputs light guided inside, as shown in FIG. 2. Of the pair of main surfaces in the third light guide plate 14, the rear main surface facing the reflection sheet 15 is the third opposite main surface (second main surface) 14C located on the opposite side to the third light guide plate light output main surface 14B. The third light guide plate 14 has a function of introducing light emitted from the third LED 13 toward the third light guide plate 14 from the third light input end surface 14A, and propagating the light inside, and then raising the light toward the front side (light output side) along the Z axis direction and outputting it. The detailed structure of the third light guide plate 14 will be described later. The normal direction of the third light incident end surface 14A coincides with the Y-axis direction (the arrangement direction of the third LED 13 and the third light guide plate 14).

[0033] 1 and 2, the reflection sheet 15 is disposed so that its principal surface is parallel to each principal surface of the liquid crystal panel 11 and the third light guide plate 14, and covers the third opposite principal surface 14C of the third light guide plate 14. The reflection sheet 15 has excellent light reflectivity, and can efficiently direct light leaking from the third opposite principal surface 14C of the third light guide plate 14 toward the front side, i.e., the third light guide plate light output principal surface 14B. The reflection sheet 15 has an outer shape that is slightly larger than the third light guide plate 14, and is disposed so as to overlap almost the entire area of ​​the third opposite principal surface 14C.

[0034] As shown in Fig. 1 and Fig. 2, the first prism sheet 16 and the second prism sheet 17 are in the form of a sheet, and their respective main surfaces are parallel to and overlap with the main surfaces of the liquid crystal panel 11 and the third light guide plate 14. The first prism sheet 16 and the second prism sheet 17 have their main surfaces parallel to the X-axis direction and the Y-axis direction, and the normal direction (thickness direction) of the main surfaces coincides with the Z-axis direction. The first prism sheet 16 and the second prism sheet 17 are laminated on the front side of the third light guide plate 14, and have a function of giving a predetermined optical effect to the light emitted from the third light guide plate light output main surface 14B of the third light guide plate 14 and emitting the light. The first prism sheet 16 and the second prism sheet 17 are arranged to overlap at least the entire display area AA in a plan view.

[0035] As shown in Fig. 2, the first prism sheet 16 has a sheet-like first base material 16A and a first prism 16B provided on the main surface (light output main surface) of the front side (light output side) of the first base material 16A. The first base material 16A is made of a substantially transparent synthetic resin, specifically, a crystalline transparent resin material such as PET (polyethylene terephthalate). In manufacturing the first base material 16A, the raw material crystalline transparent resin material is stretched in a biaxial stretching process to form a sheet-like shape, which is suitable for reducing manufacturing costs. The first prism 16B is made of a substantially transparent ultraviolet curable resin material, which is a type of photocurable resin material. In manufacturing the first prism sheet 16, for example, an uncured ultraviolet-curable resin material is filled in a mold for molding, and the first base material 16A is placed on the open end of the mold so that the uncured ultraviolet-curable resin material is arranged in contact with the main surface on the front side. In this state, when ultraviolet rays are irradiated onto the ultraviolet-curable resin material through the first base material 16A, the ultraviolet-curable resin material is cured, and the first prism 16B is integrally provided with the first base material 16A. The ultraviolet-curable resin material constituting the first prism 16B is, for example, an acrylic resin such as PMMA. The refractive index of the ultraviolet-curable resin material constituting the first prism 16B is preferably in the range of 1.49 to 1.52, and most preferably 1.49.

[0036] As shown in Fig. 4, the first prism 16B is provided in a shape that protrudes from the main surface of the first base material 16A toward the front side (opposite the third light guide plate 14 side) along the Z-axis direction. The first prism 16B has a cross-sectional shape cut along the Y-axis direction (a second direction perpendicular to the first direction) that is substantially triangular (substantially mountain-shaped) and extends linearly along the X-axis direction, and a plurality of the first prisms 16B are continuously arranged side by side along the Y-axis direction on the main surface of the first base material 16A with almost no space therebetween. The first prism 16B has a pair of inclined surfaces 16B1 and 16B2. Of the pair of inclined surfaces 16B1 and 16B2 of the first prism 16B, the one on the third LED 13 side in the Y-axis direction is referred to as the first prism inclined surface 16B1, and the one on the opposite side is referred to as the second prism inclined surface 16B2. The first prism slope 16B1 has an inclination that rises from the third LED 13 side (left side in FIG. 4) in the Y-axis direction of the first prism sheet 16 toward the opposite side (right side in FIG. 4). The first prism slope 16B1 is refracted by light that mainly travels toward the third LED 13 in the Y-axis direction among the light incident on the first prism 16B. The second prism slope 16B2 has an inclination that rises from the opposite side from the third LED 13 side in the Y-axis direction of the first prism sheet 16 (right side in FIG. 4) toward the third LED 13 side (left side in FIG. 4). The second prism slope 16B2 is refracted by light that mainly travels away from the third LED 13 in the Y-axis direction among the light incident on the first prism 16B. Most of the light refracted by the pair of inclined surfaces 16B1 and 16B2 of the first prism 16B is selectively tilted in the Y-axis direction and collected.

[0037] As shown in FIG. 4, the first prism 16B has a larger inclination angle θ1 of the first prism slope 16B1 with respect to the Y-axis direction than the inclination angle θ2 of the second prism slope 16B2 with respect to the Y-axis direction. That is, the first prism 16B has an asymmetrical cross-sectional shape in the form of a scalene triangle. Specifically, the inclination angle θ1 of the first prism slope 16B1 with respect to the Y-axis direction is preferably in the range of 50° to 60°, and is most preferably 55°. On the other hand, the inclination angle θ2 of the second prism slope 16B2 with respect to the Y-axis direction is preferably in the range of 35° to 50°, and is most preferably 45°. The angle θ3 between the pair of slopes 16B1 and 16B2 in the first prism 16B is preferably in the range of 70° to 95°, and is most preferably 80°. The multiple first prisms 16B lined up along the Y-axis direction all have approximately the same height dimensions, width dimensions, and inclination angles of each inclined surface 16B1, 16B2 relative to the Y-axis direction, and the arrangement spacing between adjacent first prisms 16B is also approximately constant and equally spaced.

[0038] As shown in FIG. 2, the second prism sheet 17 has a sheet-like second base material 17A and a second prism 17B provided on the main surface (light output main surface) of the front side (light output side) of the second base material 17A. The second base material 17A is made of a nearly transparent synthetic resin, specifically, for example, the same crystalline transparent resin material as the first base material 16A, such as PET. The second prism 17B is made of a nearly transparent ultraviolet curable resin material, which is a type of photocurable resin material. The manufacturing method of the second prism sheet 17 is the same as the manufacturing method of the first prism sheet 16 described above. The ultraviolet curable resin material constituting the second prism 17B is, for example, an acrylic resin such as PMMA, and its refractive index is set higher than that of the material of the first prism 16B, for example, about 1.61.

[0039] As shown in Fig. 4, the second prism 17B is provided in a shape that protrudes from the main surface of the second base material 17A toward the front side (the side opposite to the first prism sheet 16) along the Z-axis direction. The cross section of the second prism 17B cut along the Y-axis direction is substantially triangular (substantially mountain-shaped) and extends linearly along the X-axis direction, and a plurality of the second prisms 17B are continuously arranged side by side along the Y-axis direction with almost no space therebetween on the main surface of the second base material 17A. The second prism 17B has a pair of inclined surfaces 17B1 and 17B2. Of the pair of inclined surfaces 17B1 and 17B2 of the second prism 17B, the one on the third LED 13 side in the Y-axis direction is referred to as the third prism inclined surface (fifth inclined surface) 17B1, and the one on the opposite side is referred to as the fourth prism inclined surface (sixth inclined surface) 17B2. The third prism slope 17B1 has an inclination that rises from the third LED 13 side (left side in FIG. 4) in the Y-axis direction of the second prism sheet 17 toward the opposite side (right side in FIG. 4). Of the light incident on the second prism 17B, the light traveling mainly toward the third LED 13 in the Y-axis direction hits the third prism slope 17B1 and is refracted. The fourth prism slope 17B2 has an inclination that rises from the opposite side from the third LED 13 side in the Y-axis direction of the second prism sheet 17 (right side in FIG. 4) toward the third LED 13 side (left side in FIG. 4). Of the light incident on the second prism 17B, the light traveling mainly away from the third LED 13 in the Y-axis direction hits the fourth prism slope 17B2 and is refracted. Most of the light refracted by the pair of inclined surfaces 17B1 and 17B2 of the second prism 17B is selectively tilted in the Y-axis direction and collected.

[0040] As shown in FIG. 4, the second prism 17B has the same inclination angle θ4 of the third prism slope 17B1 with respect to the Y-axis direction and the same inclination angle θ5 of the fourth prism slope 17B2 with respect to the Y-axis direction. That is, the second prism 17B has a symmetrical cross-sectional shape of an isosceles triangle. In addition, the inclination angles θ4 and θ5 of the third prism slope 17B1 and the fourth prism slope 17B2 with respect to the Y-axis direction are smaller than the inclination angle θ1 of the first prism slope 16B1 with respect to the Y-axis direction. Specifically, the inclination angles θ4 and θ5 of the third prism slope 17B1 and the fourth prism slope 17B2 with respect to the Y-axis direction are preferably in the range of 40° to 50°, and most preferably 45°. In contrast, the angle θ6 between the pair of inclined surfaces 17B1, 17B2 in the second prism 17B is preferably in the range of 80° to 100°, and is most preferably 90°, i.e., a right angle. The second prisms 17B arranged along the Y-axis direction are all substantially identical in height, width, and inclination angle of each surface 17B1, 17B2 with respect to the Y-axis direction, and the arrangement intervals between adjacent second prisms 17B are also substantially constant and arranged at equal intervals. In order to suppress the occurrence of interference fringes called moire, it is preferable that the height and arrangement interval of the second prisms 17B are different from those of the first prism 16B.

[0041] The first prism sheet 16 and the second prism sheet 17 configured as described above provide the following actions and effects. That is, most of the light emitted from the third light guide plate light output main surface 14B of the third light guide plate 14 and incident on the first prism sheet 16 is refracted by hitting the second prism slope 16B2 of the first prism 16B, and is either emitted while being raised or directed toward the first prism slope 16B1. Here, the inclination angle θ1 of the first prism 16B with respect to the Y-axis direction is larger than the inclination angle θ2 of the second prism 17B, so that the light incident on the first prism sheet 16 is less likely to hit the first prism slope 16B1 compared to a hypothetical case in which the angles are the same or the magnitudes of the angles are reversed. When the incident light of the first prism sheet 16 strikes the first prism inclined surface 16B1 of the first prism 16B, it tends to be emitted as side lobe light (stray light) without being raised when it leaves the first prism 16B. Therefore, if it becomes difficult for the incident light of the first prism sheet 16 to directly strike the first prism inclined surface 16B1 of the first prism 16B, the generation of side lobe light is suppressed, and as a result, the light utilization efficiency is improved.

[0042] Most of the light that leaves the first prism sheet 16 and enters the second prism sheet 17 is refracted by the fourth prism slope 17B2 of the second prism 17B, and either leaves while rising or travels toward the third prism slope 17B1. Since the inclination angle θ2 of the second prism 17B relative to the Y-axis direction is smaller than the inclination angle θ1 of the first prism 16B, the light that is refracted by the fourth prism slope 17B2 and travels toward the third prism slope 17B1 is more likely to be returned to the first prism sheet 16 side by the third prism slope 17B1, compared to a case where the angles are the same or the magnitudes of the angles are reversed. As a result, the amount of light returned from the second prism sheet 17 to the first prism sheet 16 side (hereinafter referred to as retrolight) increases. This retroreflected light is reflected within the backlight device 12 and reaches the second prism sheet 17 again, where it is raised by one of the pair of inclined faces 17B1, 17B2 of the second prism 17B before being emitted, improving the light utilization efficiency. Since the optical path of the retroreflected light from the second prism sheet 17 to the emission is complicated, the rising angle given by the second prism 17B is also diversified, thereby improving the viewing angle characteristics. As a result, the viewing angle characteristics and brightness are improved.

[0043] Next, the detailed structure of the third light guide plate 14 will be described. As shown in FIG. 4 and FIG. 5, the third light guide plate 14 is provided with a first light guide plate lens 32, a second light guide plate lens 33, and a third light guide plate lens 34. As shown in FIG. 5, the first light guide plate lens 32 is provided on the third light guide plate light output main surface 14B of the third light guide plate 14. The first light guide plate lens 32 extends along the Y axis direction, and a plurality of first light guide plate lenses are arranged side by side along the X axis direction. In this embodiment, the first light guide plate lens 32 is a so-called lenticular lens. The first light guide plate lens 32 is a convex lens that protrudes from the third light guide plate light output main surface 14B to the front side. In detail, the first light guide plate lens 32 has a semicircular cross section cut along the X axis direction and a semicircular shape that extends linearly along the Y axis direction, and its surface is a first arc-shaped surface 32A. When the angle that the tangent at the base end of first arcuate surface 32A makes with respect to the X-axis direction is defined as the "contact angle," the contact angle of first light guide plate lens 32 is, for example, about 62°. The contact angles, width dimensions (arrangement intervals), and height dimensions of the multiple first light guide plate lenses 32 aligned along the X-axis direction are all substantially the same. To provide first light guide plate lens 32 having such a configuration integrally with third light guide plate 14, for example, third light guide plate 14 may be manufactured by injection molding, and a transfer shape for transferring first light guide plate lens 32 may be formed in advance on a molding surface of the molding die for molding third light guide plate light output main surface 14B.

[0044] As shown in FIG. 5, the second light guide plate lens 33 is provided on the third opposite principal surface 14C of the third light guide plate 14. The second light guide plate lens 33 extends along the Y-axis direction, and a plurality of second light guide plate lenses 33 are arranged side by side along the X-axis direction. In this embodiment, the second light guide plate lens 33 is a convex prism protruding from the third opposite principal surface 14C to the rear side. More specifically, the second light guide plate lens 33 has a cross-sectional shape cut along the X-axis direction that is substantially triangular (substantially mountain-shaped) and extends linearly along the Y-axis direction. The second light guide plate lens 33 has a width dimension (dimension in the X-axis direction) that is constant over the entire length in the Y-axis direction. The second light guide plate lens 33 has a cross-sectional shape that is substantially an isosceles triangle, and has a pair of first light guide plate inclined surfaces 33A. The apex angle of the second light guide plate lens 33 is preferably an obtuse angle (an angle exceeding 90°), specifically, in the range of 100° to 150°, and most preferably 140°. The second light guide plate lenses 33 arranged along the X-axis direction all have substantially the same apex angle, width (arrangement interval), and height. In this embodiment, the arrangement interval of the second light guide plate lenses 33 is greater than the arrangement interval of the first light guide plate lenses 32. To provide the second light guide plate lenses 33 configured in this manner integrally with the third light guide plate 14, for example, the third light guide plate 14 may be manufactured by injection molding, and a transfer shape for transferring the second light guide plate lenses 33 may be formed in advance on a molding surface of the molding die for molding the third light guide plate light-emitting main surface 14B.

[0045] According to the third light guide plate 14 having such a configuration, the light propagating in the third light guide plate 14 is repeatedly reflected by hitting the first arcuate surfaces 32A of the first light guide plate lenses 32 on the third light guide plate light output main surface 14B side in the Z axis direction, and proceeds in a zigzag manner approximately along the X axis direction, as shown in Fig. 5. On the other hand, the light propagating in the third light guide plate 14 is repeatedly reflected by hitting the pair of first light guide plate inclined surfaces 33A of the second light guide plate lenses 33 on the third opposite main surface 14C side in the Z axis direction, and proceeds in a zigzag manner approximately along the Y axis direction. As a result, the spread of the light propagating in the third light guide plate 14 in the X axis direction is limited, so that unevenness in brightness is less likely to occur between the vicinity of the third LED 13 and its surroundings in the X axis direction.

[0046] As shown in FIG. 4, the third light guide plate lens 34 is provided on the third opposite principal surface 14C of the third light guide plate 14. A plurality of the third light guide plate lenses 34 are arranged in a line at intervals along the Y-axis direction. The third light guide plate lens 34 protrudes from the third opposite principal surface 14C toward the rear side along the Z-axis direction. The third light guide plate lens 34 has a second light guide plate inclined surface 34A arranged on the opposite side to the third LED 13 side in the Y-axis direction (right side in FIG. 4), a third light guide plate inclined surface 34B arranged on the third LED 13 side in the Y-axis direction (left side in FIG. 4), and a fourth light guide plate inclined surface 34C located between the second light guide plate inclined surface 34A and the third light guide plate inclined surface 34B. The second light guide plate inclined surface 34A has an inclination that rises from the third LED 13 side in the Y-axis direction of the third light guide plate 14 (left side in FIG. 4) toward the opposite side (right side in FIG. 4). The third light guide plate inclined surface 34B has an inclination that rises from the side opposite to the third LED 13 side in the Y-axis direction in the third light guide plate 14 (the right side in FIG. 4) toward the third LED 13 side (the left side in FIG. 4). The fourth light guide plate inclined surface 34C has an inclination that rises from the third LED 13 side (the left side in FIG. 4) in the Y-axis direction in the third light guide plate 14 toward the opposite side (the right side in FIG. 4).

[0047] As shown in FIG. 4, the second light guide plate inclined surface 34A and the third light guide plate inclined surface 34B can reflect the light propagating in the third light guide plate 14 and raise it toward the front side at an angle close to the Z-axis direction, thereby promoting the emission from the third light guide plate light output main surface 14B. Therefore, it can be said that the third light guide plate lenses 34 having the second light guide plate inclined surface 34A and the third light guide plate inclined surface 34B constitute a "third light reflecting portion 37" that reflects the light present in the third light guide plate 14 and promotes the emission of light. In detail, the second light guide plate inclined surface 34A mainly functions to reflect and raise the light traveling away from the third LED 13 in the Y-axis direction. On the other hand, the third light guide plate inclined surface 34B mainly functions to reflect and raise the light traveling toward the third LED 13 in the Y-axis direction. The second light guide plate inclined surface 34A has a gradient such that the distance from the third light guide plate light output main surface 14B (a portion where the third light guide plate lens 34 is not installed) decreases as the second light guide plate inclined surface 34A moves away from the third LED 13 in the Y-axis direction. The second light guide plate inclined surface 34A has an inclination angle of, for example, about 8° with respect to the Y-axis direction. The third light guide plate inclined surface 34B has a gradient such that the distance from the third light guide plate light output main surface 14B increases with the distance from the third LED 13 in the Y-axis direction, that is, a gradient opposite to that of the second light guide plate inclined surface 34A. The third light guide plate inclined surface 34B has an inclination angle of, for example, about 80° with respect to the Y-axis direction, which is a steep gradient close to vertical and is larger than the inclination angle of the second light guide plate inclined surface 34A.

[0048] 4, 6 and 7, the third light guide plate lenses 34 arranged along the Y-axis direction are designed so that their height dimension (dimension in the Z-axis direction) and length dimension (dimension in the Y-axis direction) increase as they move away from the third LED 13 in the Y-axis direction. More specifically, when a third light guide plate lens 34 close to the third LED 13 in the Y-axis direction is compared with a third light guide plate lens 34 far from the third LED 13 in the Y-axis direction, the latter has larger areas of the second light guide plate inclined surface 34A and the third light guide plate inclined surface 34B than the former. As a result, on the side closer to the third LED 13 in the Y-axis direction, light is less likely to strike the second light guide plate inclined surface 34A and the third light guide plate inclined surface 34B of the third light guide plate lens 34, suppressing light output, but on the side farther from the third LED 13 in the Y-axis direction, light is more likely to strike the second light guide plate inclined surface 34A and the third light guide plate inclined surface 34B of the third light guide plate lens 34, promoting light output. As a result, the amount of light output from the third light guide plate light output main surface 14B is uniform between the third LED 13 side and the opposite side in the Y-axis direction.

[0049] As shown in Fig. 4, the end of the fourth light guide plate inclined surface 34C on the opposite side to the third LED 13 side in the Y-axis direction (the right side in Fig. 4) is connected to the second light guide plate inclined surface 34A, and the end of the fourth light guide plate inclined surface 34C on the third LED 13 side in the Y-axis direction (the left side in Fig. 4) is connected to the third light guide plate inclined surface 34B. The fourth light guide plate inclined surface 34C has a gradient such that the distance from the third light guide plate light output main surface 14B (the portion where the third light guide plate lens 34 is not installed) increases as it moves away from the third LED 13 in the Y-axis direction. In other words, the fourth light guide plate inclined surface 34C has the same gradient as the third light guide plate inclined surface 34B. The fourth light guide plate inclined surface 34C has an inclination angle with respect to the Y-axis direction of, for example, about 1.4°, which is smaller than the inclination angles of the second light guide plate inclined surface 34A and the third light guide plate inclined surface 34B. The fourth light guide plate inclined surface 34C having such a configuration reflects the light traveling in the third light guide plate 14 away from the third LED 13, and directs the light toward the third light guide plate light output main surface 14B, but the angle of incidence of the light with respect to the third light guide plate light output main surface 14B does not exceed the critical angle. Therefore, the light is totally reflected by the third light guide plate light output main surface 14B and is guided away from the third LED 13. This makes it difficult for the light emitted from the third light guide plate light output main surface 14B to be biased toward the third LED 13 in the Y-axis direction. As described above, the third light guide plate 14 is configured such that the inclination angle with respect to the Y-axis direction increases in the order of the fourth light guide plate inclined surface 34C, the second light guide plate inclined surface 34A, and the third light guide plate inclined surface 34B. Further, the multiple fourth light guide plate inclined surfaces 34C aligned along the Y axis direction are designed to have a smaller length dimension in the Y axis direction as they move away from the third LED 13. This is because the length dimension of the third light guide plate lens 34 increases as it moves away from the third LED 13 in the Y axis direction, and the range occupied by the third light guide plate lens 34 increases.

[0050] The third light guide plate lens 34 configured as above is disposed between two adjacent second light guide plate lenses 33 in the X-axis direction, as shown in Figs. 4, 6 and 7. Therefore, the third light guide plate lenses 34 are disposed so as to be alternately arranged with the second light guide plate lenses 33 in the X-axis direction. The third light guide plate lenses 34 have a maximum protruding dimension (height dimension) from the third opposite principal surface 14C that is smaller than the same protruding dimension of the second light guide plate lenses 33. Therefore, even the third light guide plate lens 34 located farthest from the third LED 13 in the Y-axis direction does not protrude further back than the second light guide plate lenses 33.

[0051] Next, the configuration of the first louver 18 will be described. As shown in FIG. 1, the first louver 18 has a sheet-like shape with its main surface parallel to the main surfaces of the liquid crystal panel 11 and the third light guide plate 14. The main surface of the first louver 18 is parallel to the X-axis direction and the Y-axis direction, and the normal direction (thickness direction) of the main surface coincides with the Z-axis direction. The first louver 18 has a function of limiting the range of the emission angle of light in the X-axis direction. The first louver 18 has a size approximately equal to that of the third light guide plate 14, the first prism sheet 16, and the second prism sheet 17 in a plan view, and is disposed so as to overlap at least the entire display area AA in a plan view. The first louver 18 has a first louver light-entering main surface (seventh main surface) 18A on the back side and a first louver light-exiting main surface (sixth main surface) 18B on the front side. First louver light entering principal surface 18A is disposed facing third light guide plate light exiting principal surface 14B of third light guide plate 14, and faces the front side (light exiting side) principal surface of second prism sheet 17. First louver light exiting principal surface 18B faces first light guide plate opposite principal surface 27C of first light guide plate 27 described later.

[0052] As shown in FIG. 5, the first louver 18 has a first light-shielding portion 18C that blocks light and a first light-transmitting portion 18D that transmits light. The first light-shielding portion 18C is made of a light-shielding resin material (light-shielding material) that is, for example, black and blocks light. The first light-shielding portion 18C is in a layered shape extending along the Y-axis direction and the Z-axis direction, and a plurality of the first light-transmitting portions 18C are arranged side by side at intervals in the X-axis direction. The first light-transmitting portion 18D is made of a light-transmitting resin material (light-transmitting material) that is almost transparent and transmits light. The first light-transmitting portion 18D is in a layered shape extending along the Y-axis direction and the Z-axis direction, and a plurality of the first light-transmitting portions 18D are arranged side by side at intervals in the X-axis direction. The plurality of first light-shielding portions 18C and first light-transmitting portions 18D are arranged side by side alternately and repeatedly in the X-axis direction. Therefore, a first light transmitting portion 18D is interposed between two adjacent first light shielding portions 18C spaced apart in the X-axis direction, and a first light shielding portion 18C is interposed between two adjacent first light transmitting portions 18D spaced apart in the X-axis direction. Light incident on the first louver light-entering main surface 18A of the first louver 18 passes through the first light transmitting portion 18D arranged between two adjacent first light shielding portions 18C in the X-axis direction, and is emitted from the first louver light-exiting main surface 18B. The emission angle in the X-axis direction of the light emitted from the first louver light-exiting main surface 18B is limited by the two adjacent first light shielding portions 18C in the X-axis direction. The emission angle of the light emitted from the first louver light-exiting main surface 18B is not limited by the first louver 18 in the Y-axis direction. The emission angle range in the X-axis direction of the light emitted from the first louver light-emitting main surface 18B is defined by two straight lines that diagonally connect the ends in the Z-axis direction of the two first light-shielding portions 18C that sandwich the first light-transmitting portion 18D. The emission angle range in the X-axis direction of the light transmitted through the first light-transmitting portion 18D changes according to the ratio of the width W1 and height H1 of the first light-transmitting portion 18D. The first louver 18 has a pair of sheet carriers that sandwich and support the first light-shielding portions 18C and the first light-transmitting portions 18D from the front and back sides. The sheet carriers are made of a translucent resin material that is almost transparent and transmits light. The sheet carriers extend over the entire area of ​​the first louver 18 and hold the first light-shielding portions 18C and the first light-transmitting portions 18D collectively.

[0053] Specifically, as shown in FIG. 5, the ratio of the width W1 of the first light-transmitting portion 18D divided by the height H1 of the first louver 18 is equal to "tan 10°". In this way, the maximum absolute value of the angle that the light passing through the first light-transmitting portion 18D makes with respect to the Z-axis direction is, for example, 10°. As compared to the case where the ratio of the width of the first light-transmitting portion 18D divided by the height is larger than "tan 10°", the emission angle range of the emitted light of the backlight device 12 is sufficiently narrowed. This is suitable for restricting the viewing angle so that the display image of the second display portion AA2 located in front of the passenger seat in the display area AA cannot be viewed at least from the driver's seat. Also, as compared to the case where the ratio of the width of the first light-transmitting portion 18D divided by the height is smaller than "tan 10°", the amount of light blocked by the first light-shielding portion 18C is reduced, and the light utilization efficiency is improved.

[0054] Next, the configuration of the second backlight unit 12U2 will be described. The second backlight unit 12U2 includes at least a second LED (second light source) 20 and a second light guide plate 21 that guides the light from the second LED 20, as shown in Fig. 1 and Fig. 2.

[0055] As shown in FIG. 1, the second LED 20 is substantially block-shaped, and one of a pair of surfaces along the Y-axis direction and the Z-axis direction is the second light-emitting surface 20A that emits light. As shown in FIG. 3, the second LED 20 is arranged in a row at intervals along the Y-axis direction. The second LED 20 is mounted on an LED substrate. The second LED 20 is configured by sealing an LED chip on a substrate portion mounted on the LED substrate with a sealing material. The LED chip in the second LED 20 emits monochromatic light, for example, blue light. The sealing material in the second LED 20 contains a phosphor dispersed therein. The phosphor contained in the sealing material includes a yellow phosphor, a green phosphor, a red phosphor, and the like. The second LED 20 including such an LED chip and sealing material emits white light as a whole.

[0056] The second light guide plate 21 is made of a synthetic resin material (e.g., acrylic resin such as PMMA) that has a refractive index sufficiently higher than that of air and is almost transparent. As shown in FIG. 1, the second light guide plate 21 is plate-shaped, and its main surface is parallel to and overlaps with the main surface of the liquid crystal panel 11, etc. The main surface of the second light guide plate 21 is parallel to the X-axis direction and the Y-axis direction, and the normal direction (thickness direction) of the main surface coincides with the Z-axis direction. The second light guide plate 21 is arranged to overlap at least the entire display area AA in a plan view. The second light guide plate 21 is arranged along the X-axis direction (first direction) with respect to the second LED 20, and is arranged along the Z-axis direction with respect to the liquid crystal panel 11, the third light guide plate 14, the first louver 18, etc. The second light guide plate 21 is arranged on the other side in the X-axis direction (left side in FIG. 1) with respect to the second LED 20. That is, the positional relationship between the second light guide plate 21 and the second LEDs 20 (positional relationship aligned along the X-axis direction) is orthogonal to the positional relationship between the third light guide plate 14 and the third LEDs 13 (positional relationship aligned along the Y-axis direction) as shown in Fig. 3. Since the third LEDs 13 and the second LEDs 20 are thus disposed in a dispersed manner in a plan view, heat is unlikely to build up even when the third LEDs 13 and the second LEDs 20 are each turned on.

[0057] As shown in FIG. 1, one end surface of the outer peripheral end surface of the second light guide plate 21 is a second light-entering end surface (second end surface) 21A facing the second light-emitting surface 20A of the second LED 20. The second light-entering end surface 21A is a surface parallel to the second light-emitting surface 20A of the second LED 20, and the light emitted from the second light-emitting surface 20A is incident on the second light guide plate 21. In this manner, the second LED 20 is disposed on only one side in the X-axis direction of the second light guide plate 21. Therefore, the second backlight unit 12U2 is a one-side light-entering edge light type. Of the pair of main surfaces of the second light guide plate 21, the front main surface facing the diffusion sheet 12S is the second light guide plate light-exiting main surface (third main surface) 21B that emits the light guided inside. Of the pair of main surfaces in the second light guide plate 21, the rear main surface facing the first light guide plate light output main surface 27B of the first light guide plate 27 described later is a second opposite main surface (fourth main surface) 21C located on the opposite side to the second light guide plate light output main surface 21B. The second light guide plate 21 is arranged such that the second opposite main surface 21C faces the first light guide plate 27 in the Z-axis direction. The second light guide plate 21 introduces light emitted from the second LED 20 toward the second light guide plate 21 from the second light input end surface 21A, and propagates the light inside, and then can emit the light by raising it from the second light guide plate light output main surface 21B along the Z-axis direction toward the diffusion sheet 12S (liquid crystal panel 11) on the front side (light output side). In addition, the second light guide plate 21 can introduce the light emitted from the first light guide plate 27 from the second opposite principal surface 21C, and can emit the light from the second light guide plate light output principal surface 21B toward the front-side diffusion sheet 12S. The normal direction of the second light incident end surface 21A coincides with the X-axis direction (the arrangement direction of the second LED 20 and the second light guide plate 21).

[0058] As shown in FIG. 4 and FIG. 5, the second light guide plate 21 is provided with a fourth light guide plate lens 22, a fifth light guide plate lens 23, and a sixth light guide plate lens (second lens) 24. As shown in FIG. 4, the fourth light guide plate lens 22 is provided on the second light guide plate light output main surface 21B of the second light guide plate 21. The fourth light guide plate lens 22 extends along the X-axis direction, and a plurality of fourth light guide plate lenses 22 are arranged side by side along the Y-axis direction. In this embodiment, the fourth light guide plate lens 22 is a so-called lenticular lens. The fourth light guide plate lens 22 is a convex lens that protrudes from the second light guide plate light output main surface 21B to the front side. In detail, the fourth light guide plate lens 22 has a semicircular cross section cut along the Y-axis direction and a semicircular shape that extends linearly along the X-axis direction, and its surface is the second arc-shaped surface 22A. When the angle that the tangent at the base end of the second arcuate surface 22A makes with respect to the Y-axis direction is defined as the "contact angle," the contact angle θc1 of the fourth light guide plate lens 22 is, for example, about 30°. The contact angles θc1, width dimensions (arrangement intervals), and height dimensions of the multiple fourth light guide plate lenses 22 aligned along the Y-axis direction are all substantially the same. To provide the fourth light guide plate lens 22 configured as described above integrally with the second light guide plate 21, for example, the second light guide plate 21 may be manufactured by injection molding, and a transfer shape for transferring the fourth light guide plate lens 22 may be formed in advance on a molding surface of the molding die for molding the second light guide plate light output main surface 21B.

[0059] As shown in FIG. 4, the fifth light guide plate lens 23 is provided on the second opposite principal surface 21C of the second light guide plate 21. The fifth light guide plate lens 23 extends along the X-axis direction, and a plurality of the fifth light guide plate lenses 23 are arranged side by side along the Y-axis direction. In this embodiment, the fifth light guide plate lens 23 is a convex prism protruding from the second opposite principal surface 21C to the rear side. More specifically, the fifth light guide plate lens 23 has a cross-sectional shape cut along the Y-axis direction that is substantially triangular (substantially mountain-shaped) and extends linearly along the X-axis direction. The fifth light guide plate lens 23 has a width dimension (dimension in the Y-axis direction) that is constant over the entire length in the X-axis direction. The fifth light guide plate lens 23 has a cross-sectional shape that is substantially an isosceles triangle, and has a pair of fifth light guide plate inclined surfaces 23A. The apex angle θ7 of the fifth light guide plate lens 23 is preferably an obtuse angle (an angle exceeding 90°), specifically, in the range of 100° to 150°, and most preferably 140°. The plurality of fifth light guide plate lenses 23 arranged along the Y-axis direction all have substantially the same apex angle θ7, width dimension (arrangement interval), and height dimension. In this embodiment, the arrangement interval of fifth light guide plate lenses 23 is greater than the arrangement interval of fourth light guide plate lenses 22. To provide fifth light guide plate lenses 23 having such a configuration integrally with second light guide plate 21, for example, second light guide plate 21 may be manufactured by injection molding, and a transfer shape for transferring fifth light guide plate lenses 23 may be formed in advance on a molding surface of a molding die for molding second opposite principal surface 21C.

[0060] The sixth light guide plate lens 24 is provided on the second opposite principal surface 21C of the second light guide plate 21, as shown in FIG. 5. The sixth light guide plate lenses 24 are arranged in a row at intervals along the X-axis direction. The sixth light guide plate lenses 24 protrude from the second opposite principal surface 21C toward the rear side along the Z-axis direction. The sixth light guide plate lens 24 has a sixth light guide plate inclined surface 24A arranged on the opposite side to the second LED 20 side in the X-axis direction (left side in FIG. 5), a seventh light guide plate inclined surface 24B arranged on the second LED 20 side in the X-axis direction (right side in FIG. 5), and a first flat surface 24C located between the sixth light guide plate inclined surface 24A and the seventh light guide plate inclined surface 24B. The sixth light guide plate inclined surface 24A has an inclination that rises from the second LED 20 side in the X-axis direction of the second light guide plate 21 (right side in FIG. 5) toward the opposite side (left side in FIG. 5). The seventh light guide plate inclined surface 24B has an inclination that rises from the side opposite to the second LED 20 side in the X-axis direction of the second light guide plate 21 (the left side in FIG. 5) toward the second LED 20 side (the right side in FIG. 5). The first flat surface 24C is a surface parallel to the X-axis direction and the Y-axis direction. In addition, a second flat surface 25 is provided between two sixth light guide plate lenses 24 adjacent to each other in the X-axis direction. Therefore, the sixth light guide plate lenses 24 and the second flat surface 25 are arranged alternately and repeatedly along the X-axis direction.

[0061] As shown in FIG. 5, the sixth light guide plate inclined surface 24A can reflect the light propagating in the second light guide plate 21 and raise it toward the front side, thereby promoting the emission from the second light guide plate light output main surface 21B. Therefore, it can be said that the sixth light guide plate lenses 24 having the sixth light guide plate inclined surface 24A constitute a "second light reflecting portion 36" that reflects the light present in the second light guide plate 21 and promotes the emission of light. In detail, the sixth light guide plate inclined surface 24A mainly functions to reflect and raise the light traveling in the second light guide plate 21 in the X-axis direction away from the second LED 20. Specifically, as shown in FIG. 8, the sixth light guide plate inclined surface 24A has an inclination angle (angle) θ8 with respect to the X-axis direction of, for example, 40° or less, preferably about 27°. If the inclination angle θ8 of the sixth light guide plate inclined surface 24A with respect to the X-axis direction is set to 40° or less, the light can be raised in a direction inclined toward the opposite side of the second LED 20 side with respect to the X-axis direction with respect to the front direction. Therefore, the light emitted from the second light guide plate light output main surface 21B contains more light toward the opposite side of the second LED 20 side with respect to the Z-axis direction (normal direction of the second light guide plate light output main surface 21B) with respect to the X-axis direction than light toward the second LED 20 side with respect to the X-axis direction. Therefore, when the second LED 20 is turned on, it is possible to supply emitted light with a luminance angle distribution in which the peak luminance of the emitted light is unevenly distributed on the opposite side of the second LED 20 side with respect to the X-axis direction. In the liquid crystal display device 10 for vehicle mounting according to this embodiment, it is preferable to arrange the second LED 20 on the opposite side of the driver's seat side with respect to the X-axis direction, that is, on the passenger seat side.

[0062] On the other hand, as shown in FIG. 5, the seventh light guide plate inclined surface 24B can reflect and raise the light traveling in the X-axis direction toward the second LED 20, or can reflect and guide the light traveling in the second light guide plate 21 away from the second LED 20 in the X-axis direction to further away from the second LED 20. Specifically, as shown in FIG. 8, the seventh light guide plate inclined surface 24B has an inclination angle (angle) θ9 with respect to the X-axis direction in the range of, for example, 3° to 10°, and preferably about 3°. The inclination angle θ9 of the seventh light guide plate inclined surface 24B is smaller than the inclination angle θ8 of the sixth light guide plate inclined surface 24A. According to the seventh light guide plate inclined surface 24B having such a configuration, when the light traveling in the second light guide plate 21 toward the second LED 20 in the X-axis direction hits the seventh light guide plate inclined surface 24B and is refracted, it travels toward the opposite side of the second LED 20 in the X-axis direction with respect to the front direction. This can further improve the brightness of the emitted light in a direction inclined with respect to the front direction. Also, when the light traveling in the second light guide plate 21 so as to move away from the second LED 20 in the X-axis direction hits the seventh light guide plate inclined surface 24B and is refracted, it is guided so as to move further away from the second LED 20. This makes it difficult for the emitted light from the second light guide plate light output main surface 21B to be biased toward the second LED 20 in the X-axis direction.

[0063] 5, the first plane 24C and the second plane 25 are parallel to the X-axis direction and the Y-axis direction, and their normal directions coincide with the Z-axis direction. The light emitted from the first light guide plate 27 described later and incident on the second opposite principal surface 21C of the second light guide plate 21 proceeds without being refracted even if it hits either the first plane 24C or the second plane 25. Therefore, compared with a configuration in which the sixth light guide plate inclined surface 24A and the seventh light guide plate inclined surface 24B are directly connected without the first plane 24C therebetween or a configuration in which two sixth light guide plate lenses 24 adjacent to each other in the X-axis direction are directly connected without the second plane 25 therebetween, it is possible to suppress the generation of side lobe light that proceeds in a direction inclined toward the opposite side to the second LED 20 side in the X-axis direction with respect to the front direction.

[0064] As shown in Figs. 8 and 9, the sixth light guide plate lenses 24 arranged along the X-axis direction are designed so that the height dimension (dimension in the Z-axis direction) increases as they move away from the second LED 20 in the X-axis direction, but the arrangement pitch (arrangement interval) in the X-axis direction is constant. The width dimension (dimension in the X-axis direction) of the sixth light guide plate inclined surface 24A increases slightly as they move away from the second LED 20 in the X-axis direction. The width dimension (dimension in the X-axis direction) of the seventh light guide plate inclined surface 24B increases as they move away from the second LED 20 in the X-axis direction, and the increase rate is higher than that of the sixth light guide plate inclined surface 24A. The width dimension (dimension in the X-axis direction) of the first plane 24C is constant regardless of the position in the X-axis direction. The width dimension (dimension in the X-axis direction) of the second plane 25 decreases as it moves away from the second LED 20 in the X-axis direction. The arrangement pitch of the sixth light guide plate lenses 24 in the X-axis direction is the sum of the width dimension of the sixth light guide plate inclined surface 24A, the width dimension of the seventh light guide plate inclined surface 24B, the width dimension of the first plane 24C, and the width dimension of the second plane 25.

[0065] When the length dimension (dimension in the X-axis direction) of the second light guide plate 21 is, for example, 300 mm, the arrangement pitch of the sixth light guide plate lenses 24 in the X-axis direction is constant, for example, about 0.114 mm, and the width dimension of the first plane 24C is constant, for example, about 0.017 mm. When the length dimension of the second light guide plate 21 is, for example, 300 mm, the width dimension of the sixth light guide plate inclined surface 24A varies depending on the position of the sixth light guide plate lens 24 in the second light guide plate 21 in the X-axis direction, for example, within a range of 0.002 mm to 0.005 mm. When the length dimension of the second light guide plate 21 is, for example, 300 mm, the width dimension of the seventh light guide plate inclined surface 24B varies depending on the position of the sixth light guide plate lens 24 in the second light guide plate 21 in the X-axis direction, for example, within a range of 0.032 mm to 0.005 mm. When the length of the second light guide plate 21 is, for example, 300 mm, the width of the second plane 25 varies, for example, within a range of 0.038 mm to 0.063 mm, depending on the position of the sixth light guide plate lens 24 in the second light guide plate 21 in the X-axis direction. The height of the sixth light guide plate lens 24 is ensured to be, for example, about 0.002 mm (2 μm) at a minimum. This allows the second light guide plate 21 to be easily manufactured by resin molding. In order to ensure that the minimum value of the height of the sixth light guide plate lens 24 is about 0.002 mm, it is preferable that the inclination angle θ9 of the seventh light guide plate inclined surface 24B with respect to the X-axis direction is 3° or more. Note that the inclination angle θ8 of the sixth light guide plate inclined surface 24A with respect to the X-axis direction and the inclination angle θ9 of the seventh light guide plate inclined surface 24B with respect to the X-axis direction are constant, regardless of the position of the second light guide plate 21 in the X-axis direction.

[0066] The sixth light guide plate lens 24 configured as above is disposed between two fifth light guide plate lenses 23 adjacent to each other in the Y-axis direction, as shown in Fig. 4 and Fig. 9. Therefore, the sixth light guide plate lenses 24 are disposed so as to be alternately arranged with the fifth light guide plate lenses 23 in the Y-axis direction. The sixth light guide plate lenses 24 have a maximum height (a protruding dimension from the second opposite principal surface 21C) smaller than the height of the fifth light guide plate lenses 23. Therefore, even the sixth light guide plate lens 24 located farthest from the second LED 20 in the X-axis direction does not protrude further back than the fifth light guide plate lens 23.

[0067] Next, the configuration of the first backlight unit 12U1 will be described. The first backlight unit 12U1 includes at least a first LED (first light source) 26 and a first light guide plate 27 that guides the light from the first LED 26, as shown in FIG.

[0068] As shown in FIG. 1, the first LED 26 is substantially block-shaped, and one of a pair of surfaces along the Y-axis direction and the Z-axis direction is the first light-emitting surface 26A that emits light. As shown in FIG. 3, the first LED 26 is arranged in a row at intervals along the Y-axis direction. The first LED 26 is mounted on an LED board. The first LED 26 is configured by sealing an LED chip on a board portion mounted on the LED board with a sealing material. The LED chip provided in the first LED 26 emits a single color light, for example, blue light. The sealing material provided in the first LED 26 has a phosphor dispersed therein. The phosphor contained in the sealing material includes a yellow phosphor, a green phosphor, a red phosphor, and the like. The first LED 26 provided with such an LED chip and sealing material emits white light as a whole.

[0069] The first light guide plate 27 is made of a synthetic resin material (e.g., acrylic resin such as PMMA) that has a refractive index sufficiently higher than that of air and is almost transparent. As shown in FIG. 1, the first light guide plate 27 is plate-shaped, and its main surface is parallel to and overlaps with the main surface of the liquid crystal panel 11, etc. The main surface of the first light guide plate 27 is parallel to the X-axis direction and the Y-axis direction, and the normal direction (thickness direction) of the main surface coincides with the Z-axis direction. The first light guide plate 27 is arranged to overlap at least the entire display area AA in a plan view. The main surfaces of the first light guide plate 27 overlap with the second light guide plate 21. The first light guide plate 27 and the second light guide plate 21 that overlap with each other are arranged on the opposite side (front side) of the first louver 18 from the third light guide plate 14 side. The first light guide plate 27 is arranged along the X-axis direction (first direction) with respect to the first LED 26, and along the Z-axis direction with respect to the liquid crystal panel 11, the third light guide plate 14, the first louver 18, etc. The first light guide plate 27 is arranged on the other side in the X-axis direction (the left side in FIG. 1) with respect to the first LED 26. That is, the positional relationship between the first light guide plate 27 and the first LED 26 (the positional relationship in the X-axis direction) is the same as the positional relationship between the second light guide plate 21 and the second LED 20 (the positional relationship in the X-axis direction), as shown in FIG. 3, and is perpendicular to the positional relationship between the third light guide plate 14 and the third LED 13 (the positional relationship in the Y-axis direction). In this way, since the third LED 13 and the first LED 26 are arranged in a dispersed manner in a plan view, heat is less likely to build up even when the third LED 13 and the first LED 26 are turned on.

[0070] As shown in FIG. 1, one end surface of the outer peripheral end surface of the first light guide plate 27 is a first light-entering end surface (first end surface) 27A facing the first light-emitting surface 26A of the first LED 26. The first light-entering end surface 27A is a surface parallel to the first light-emitting surface 26A of the first LED 26, and light emitted from the first light-emitting surface 26A is incident on the first light guide plate 27. In this manner, the first LED 26 is disposed on only one side in the X-axis direction of the first light guide plate 27. Therefore, the first backlight unit 12U1 is a one-side light-entering edge light type. Of the pair of main surfaces of the first light guide plate 27, the front main surface facing the second light guide plate 21 is a first light guide plate light-exiting main surface (first main surface) 27B that emits light guided inside. Of the pair of main surfaces in the first light guide plate 27, the main surface on the back side facing the first louver 18 is a first opposite main surface (second main surface) 27C located on the opposite side to the first light guide plate light output main surface 27B. The first light guide plate 27 is arranged such that the first opposite main surface 27C faces the first louver light output main surface 18B of the first louver 18 in the Z-axis direction. The first light guide plate 27 introduces light emitted from the first LEDs 26 toward the first light guide plate 27 from the first light entrance end surface 27A, and propagates the light inside, and then can emit the light by raising it from the first light guide plate light output main surface 27B along the Z-axis direction toward the second light guide plate 21 (liquid crystal panel 11) on the front side (light output side). In addition, first light guide plate 27 can introduce light emitted from first louver 18 from first opposite principal surface 27C, and emit the light from first light guide plate light exit principal surface 27B toward second light guide plate 21 on the front side. The normal direction of first light incident end surface 27A coincides with the X-axis direction (the arrangement direction of first LED 26 and first light guide plate 27).

[0071] As shown in FIG. 4 and FIG. 5, the first light guide plate 27 is provided with a seventh light guide plate lens 28, an eighth light guide plate lens 29, and a ninth light guide plate lens (first lens) 30. As shown in FIG. 4, the seventh light guide plate lens 28 is provided on the first light guide plate light output main surface 27B of the first light guide plate 27. The seventh light guide plate lens 28 extends along the X-axis direction, and a plurality of the seventh light guide plate lenses 28 are arranged side by side along the Y-axis direction. In this embodiment, the seventh light guide plate lens 28 is a so-called lenticular lens. The seventh light guide plate lens 28 is a convex lens that protrudes from the first light guide plate light output main surface 27B to the front side. In detail, the seventh light guide plate lens 28 has a semicircular cross section cut along the Y-axis direction and a semicircular shape that extends linearly along the X-axis direction, and its surface is a third arc-shaped surface 28A. When the angle that the tangent at the base end of the third arcuate surface 28A makes with respect to the Y-axis direction is defined as the "contact angle," the contact angle θc2 of the seventh light guide plate lens 28 is, for example, about 30°. The contact angles θc2, width dimensions (arrangement intervals), and height dimensions of the multiple seventh light guide plate lenses 28 aligned along the Y-axis direction are all substantially the same. To provide the seventh light guide plate lens 28 having such a configuration integrally with the first light guide plate 27, for example, the first light guide plate 27 may be manufactured by injection molding, and a transfer shape for transferring the seventh light guide plate lens 28 may be formed in advance on a molding surface of the molding die for molding the first light guide plate light output main surface 27B.

[0072] As shown in FIG. 4, the eighth light guide plate lens 29 is provided on the first opposite principal surface 27C of the first light guide plate 27. The eighth light guide plate lens 29 extends along the X-axis direction, and a plurality of eighth light guide plate lenses 29 are arranged side by side along the Y-axis direction. In this embodiment, the eighth light guide plate lens 29 is a convex prism protruding from the first opposite principal surface 27C to the rear side. More specifically, the eighth light guide plate lens 29 has a cross-sectional shape cut along the Y-axis direction that is substantially triangular (substantially mountain-shaped) and extends linearly along the X-axis direction. The width dimension (dimension in the Y-axis direction) of the eighth light guide plate lens 29 is constant over the entire length in the X-axis direction. The eighth light guide plate lens 29 has a cross-sectional shape that is substantially an isosceles triangle, and has a pair of eighth light guide plate inclined surfaces 29A. The apex angle θ10 of the eighth light guide plate lens 29 is preferably an obtuse angle (an angle exceeding 90°), specifically in the range of 100° to 150°, and most preferably 140°. The eighth light guide plate lenses 29 arranged along the Y-axis direction all have substantially the same apex angle θ10, width dimension (arrangement interval), and height dimension. In this embodiment, the arrangement interval of the eighth light guide plate lenses 29 is larger than the arrangement interval of the seventh light guide plate lenses 28. To provide the eighth light guide plate lens 29 having such a configuration integrally with the first light guide plate 27, for example, the first light guide plate 27 may be manufactured by injection molding, and a transfer shape for transferring the eighth light guide plate lens 29 may be formed in advance on a molding surface of the molding die for molding the first opposite principal surface 27C.

[0073] The ninth light guide plate lens 30 is provided on the first opposite principal surface 27C of the first light guide plate 27, as shown in FIG. 5. The ninth light guide plate lenses 30 are arranged in a row at intervals along the X-axis direction. The ninth light guide plate lens 30 protrudes from the first opposite principal surface 27C toward the rear side along the Z-axis direction. The ninth light guide plate lens 30 has a ninth light guide plate inclined surface (third inclined surface) 30A arranged on the opposite side to the first LED 26 side in the X-axis direction (left side in FIG. 5), a tenth light guide plate inclined surface 30B arranged on the first LED 26 side in the X-axis direction (right side in FIG. 5), and a third plane 30C located between the ninth light guide plate inclined surface 30A and the tenth light guide plate inclined surface 30B. The ninth light guide plate inclined surface 30A has an inclination that rises from the first LED 26 side (right side in FIG. 5) to the opposite side (left side in FIG. 5) in the X-axis direction of the first light guide plate 27. The tenth light guide plate inclined surface 30B has an inclination that rises from the opposite side (left side in FIG. 5) from the first LED 26 side in the X-axis direction of the first light guide plate 27 to the first LED 26 side (right side in FIG. 5). The third plane 30C is a plane parallel to the X-axis direction and the Y-axis direction. In addition, a fourth plane 31 is provided between two ninth light guide plate lenses 30 adjacent to each other in the X-axis direction. Therefore, the ninth light guide plate lenses 30 and the fourth plane 31 are arranged alternately and repeatedly along the X-axis direction.

[0074] As shown in FIG. 5, the ninth light guide plate inclined surface 30A can reflect the light propagating in the first light guide plate 27 and raise it toward the front side, thereby promoting the emission from the first light guide plate light output main surface 27B. Therefore, it can be said that the multiple ninth light guide plate lenses 30 having the ninth light guide plate inclined surface 30A constitute a "first light reflecting portion 35" that reflects the light present in the first light guide plate 27 and promotes the emission of light. In detail, the ninth light guide plate inclined surface 30A mainly functions to reflect and raise the light traveling in the first light guide plate 27 away from the first LED 26 in the X-axis direction. Specifically, the ninth light guide plate inclined surface 30A has an inclination angle (angle) θ11 with respect to the X-axis direction of, for example, 40° or less, and preferably about 27°. If the inclination angle θ11 of the ninth light guide plate inclined surface 30A with respect to the X-axis direction is set to 40° or less, the light can be raised in a direction inclined toward the opposite side of the first LED 26 side with respect to the X-axis direction with respect to the front direction. Therefore, the light emitted from the first light guide plate light output main surface 27B contains more light toward the opposite side of the first LED 26 side with respect to the Z-axis direction (normal direction of the first light guide plate light output main surface 27B) with respect to the X-axis direction than light toward the first LED 26 side with respect to the X-axis direction. Therefore, when the first LED 26 is turned on, it is possible to supply emitted light with a luminance angle distribution in which the peak luminance of the emitted light is biased toward the opposite side of the first LED 26 side with respect to the X-axis direction. The inclination angle θ11 of the ninth light guide plate inclined surface 30A with respect to the X-axis direction is equal to the inclination angle θ8 of the sixth light guide plate inclined surface 24A with respect to the X-axis direction. In the in-vehicle liquid crystal display device 10 according to this embodiment, it is preferable to arrange the first LED 26 on the opposite side to the driver's seat in the X-axis direction, that is, on the passenger seat side.

[0075] On the other hand, as shown in FIG. 5, the tenth light guide plate inclined surface 30B can reflect and raise the light traveling toward the first LED 26 in the X-axis direction, or can reflect and guide the light traveling in the first light guide plate 27 away from the first LED 26 in the X-axis direction to further away from the first LED 26. Specifically, the tenth light guide plate inclined surface 30B has an inclination angle (angle) θ12 with respect to the X-axis direction in the range of, for example, 3° to 10°, and preferably about 3°. The inclination angle θ12 of the tenth light guide plate inclined surface 30B is smaller than the inclination angle θ11 of the ninth light guide plate inclined surface 30A. According to the tenth light guide plate inclined surface 30B having such a configuration, when the light traveling in the first light guide plate 27 toward the first LED 26 in the X-axis direction hits the tenth light guide plate inclined surface 30B and is refracted, it travels toward the opposite side of the first LED 26 in the X-axis direction with respect to the front direction. This can further improve the brightness of the emitted light in the direction inclined with respect to the front direction. In addition, when the light traveling in the first light guide plate 27 so as to move away from the first LED 26 in the X-axis direction hits the tenth light guide plate inclined surface 30B and is refracted, it is guided so as to move further away from the first LED 26. This makes it difficult for the emitted light from the first light guide plate light output main surface 27B to be biased toward the first LED 26 in the X-axis direction. The inclination angle θ12 of the tenth light guide plate inclined surface 30B with respect to the X-axis direction is equal to the inclination angle θ9 of the seventh light guide plate inclined surface 24B with respect to the X-axis direction.

[0076] 5, the third plane 30C and the fourth plane 31 are parallel to the X-axis direction and the Y-axis direction, and their normal directions coincide with the Z-axis direction. The light emitted from the first louver 18 and incident on the first opposite principal surface 27C of the first light guide plate 27 proceeds without being refracted even if it hits either the third plane 30C or the fourth plane 31. Therefore, compared with a case in which the ninth light guide plate inclined surface 30A and the tenth light guide plate inclined surface 30B are directly connected to each other without the third plane 30C, or a case in which two ninth light guide plate lenses 30 adjacent to each other in the X-axis direction are directly connected to each other without the fourth plane 31, the generation of side lobe light proceeding in a direction inclined toward the opposite side to the first LED 26 in the X-axis direction with respect to the front direction can be suppressed.

[0077] As shown in FIG. 5, the height dimension (dimension in the Z-axis direction) of the multiple ninth light guide plate lenses 30 arranged along the X-axis direction increases as they move away from the first LED 26 in the X-axis direction, but the arrangement pitch (arrangement interval) in the X-axis direction is designed to be constant. The configuration of the ninth light guide plate lens 30 is almost the same as the configuration of the sixth light guide plate lens 24 shown in FIG. 8 and FIG. 9. The width dimension (dimension in the X-axis direction) of the ninth light guide plate inclined surface 30A increases slightly as it moves away from the first LED 26 in the X-axis direction. The width dimension (dimension in the X-axis direction) of the tenth light guide plate inclined surface 30B increases as it moves away from the first LED 26 in the X-axis direction, and the increase rate is higher than that of the ninth light guide plate inclined surface 30A. The width dimension (dimension in the X-axis direction) of the third plane 30C is constant regardless of the position in the X-axis direction. The width dimension (dimension in the X-axis direction) of the fourth plane 31 becomes smaller as it gets farther from the first LED 26 in the X-axis direction. The arrangement pitch in the X-axis direction of the ninth light guide plate lenses 30 is the sum of the width dimension of the ninth light guide plate inclined surface 30A, the width dimension of the tenth light guide plate inclined surface 30B, the width dimension of the third plane 30C, and the width dimension of the fourth plane 31.

[0078] When the length dimension (dimension in the X-axis direction) of the first light guide plate 27 is, for example, 300 mm, the arrangement pitch of the ninth light guide plate lens 30 in the X-axis direction is constant, for example, about 0.114 mm, and the width dimension of the third plane 30C is constant, for example, about 0.017 mm. When the length dimension of the first light guide plate 27 is, for example, 300 mm, the width dimension of the ninth light guide plate inclined surface 30A varies depending on the position of the ninth light guide plate lens 30 in the first light guide plate 27 in the X-axis direction, for example, within a range of 0.002 mm to 0.005 mm. When the length dimension of the first light guide plate 27 is, for example, 300 mm, the width dimension of the tenth light guide plate inclined surface 30B varies depending on the position of the ninth light guide plate lens 30 in the first light guide plate 27 in the X-axis direction, for example, within a range of 0.032 mm to 0.005 mm. When the length of the first light guide plate 27 is, for example, 300 mm, the width of the fourth plane 31 varies, for example, within a range of 0.038 mm to 0.063 mm, depending on the position of the ninth light guide plate lens 30 in the first light guide plate 27 in the X-axis direction. The height of the ninth light guide plate lens 30 is secured to a minimum value of, for example, about 0.002 mm (2 μm). This sufficiently ensures the ease of manufacturing the first light guide plate 27 by resin molding. In order to secure a minimum value of the height of the ninth light guide plate lens 30 of about 0.002 mm, it is preferable that the inclination angle θ12 of the tenth light guide plate inclined surface 30B with respect to the X-axis direction is 3° or more. Note that the inclination angle θ11 of the ninth light guide plate inclined surface 30A with respect to the X-axis direction and the inclination angle θ12 of the tenth light guide plate inclined surface 30B with respect to the X-axis direction are constant, regardless of the position of the first light guide plate 27 in the X-axis direction.

[0079] The ninth light guide plate lens 30 configured as described above is disposed between two eighth light guide plate lenses 29 adjacent to each other in the Y-axis direction, as shown in Fig. 4. Therefore, the ninth light guide plate lenses 30 are disposed so as to be alternately arranged with the eighth light guide plate lenses 29 in the Y-axis direction. The maximum value of the height dimension (projection dimension from the first opposite principal surface 27C) of the ninth light guide plate lens 30 is smaller than the height dimension of the eighth light guide plate lens 29. Therefore, even the ninth light guide plate lens 30 located farthest from the first LED 26 in the X-axis direction does not protrude further back than the eighth light guide plate lens 29.

[0080] 1, 2, and 10, the first light guide plate 27 and the second light guide plate 21 according to this embodiment are set to have the formation ranges of the first light reflecting portion 35 and the second light reflecting portion 36 as follows. That is, when the first opposite principal surface 27C is divided into a first region A1 overlapping the first display portion AA1 of the display area AA and a second region A2 overlapping the second display portion AA2 of the display area AA and adjacent to the first region A1 in the X-axis direction, the first light reflecting portion 35 is selectively provided in the first region A1 on the first opposite principal surface 27C. That is, the first light reflecting portion 35 is selectively not formed in the second region A2 on the first opposite principal surface 27C (see, in particular, FIGS. 1 and 10). In contrast, when the second opposite principal surface 21C is divided into a third region A3 overlapping the first region A1 (first display portion AA1) and a fourth region A4 overlapping the second region A2 (second display portion AA2), the second light reflecting portion 36 is provided in at least the fourth region A4 on the second opposite principal surface 21C. Specifically, the second light reflecting portion 36 is provided across the third region A3 and the fourth region A4 on the second opposite principal surface 21C, and is provided over almost the entire area of ​​the second opposite principal surface 21C. In addition, the area ratio of the first region A1 (third region A3) to the second region A2 (fourth region A4) is, for example, 1:1.

[0081] In this way, since the first light reflecting portion 35 is selectively provided in the first region A1 on the first opposite principal surface 27C, when the first LED 26 is turned on, light is emitted from the portion of the first light guide plate light output principal surface 27B that overlaps with the first region A1, but light is not emitted from the portion that overlaps with the second region A2, as shown in Figures 5 and 11. On the other hand, since the second light reflecting portion 36 is provided across the third region A3 and the fourth region A4 on the second opposite principal surface 21C, when the second LED 20 is turned on, light is emitted from the portion of the second light guide plate light output principal surface 21B that overlaps with the third region A3 and the fourth region A4, that is, from almost the entire region, as shown in Figures 4 and 5. Furthermore, with regard to the third backlight unit 12U3, when the third LED 13 is turned on, as shown in FIG. 5, the angle range of the light emitted from the third light guide plate 14 is limited in the X-axis direction by the first light-shielding portion 18C of the first louver 18 when it is emitted from the first louver light-emitting main surface 18B.

[0082] For this reason, for example, if the first LED 26 and the third LED 13 are turned on and the second LED 20 is turned off, the light emitted from the backlight device 12 includes light emitted in a limited angle range from the first louver light-emitting main surface 18B of the first louver 18 and light selectively emitted from a portion overlapping with the first region A1 on the first light-guiding plate light-emitting main surface 27B of the first light-guiding plate 27. As a result, in this case, the light emitted from the portion overlapping with the first region A1 and the third region A3 of the backlight device 12 is not limited in the emission angle range in the X-axis direction, but the light emitted from the portion overlapping with the second region A2 and the fourth region A4 of the backlight device 12 is limited in the emission angle range in the X-axis direction. Here, in this embodiment, the first area A1 and the third area A3 overlap with the first display section AA1 of the display area AA, and the second area A2 and the fourth area A4 overlap with the second display section AA2 of the display area AA. Therefore, for example, while the passenger car is running, the first LED 26 and the third LED 13 are turned on, and the second LED 20 is turned off. Then, the light emitted from the part of the backlight device 12 that overlaps with the second area A2 and the fourth area A4 is limited in the emission angle range in the X-axis direction, so that the image displayed on the second display section AA2 in front of the passenger seat can be viewed from the passenger seat but cannot be viewed from the driver's seat. On the other hand, the light emitted from the part of the backlight device 12 that overlaps with the first area A1 and the third area A3 is not limited in the emission angle range in the X-axis direction, so that the image displayed on the first display section AA1 in front of the driver's seat can be viewed from both the driver's seat and the passenger seat.

[0083] On the other hand, for example, if the second LED 20 and the third LED 13 are turned on and the first LED 26 is turned off, the light emitted from the backlight device 12 includes light emitted from the first louver light-emitting main surface 18B of the first louver 18 in a limited angle range and light emitted from the second light-guiding plate light-emitting main surface 21B of the second light-guiding plate 21 over a portion overlapping with the third region A3 and a portion overlapping with the fourth region A4. As a result, in this case, the light emitted from the backlight device 12 is not limited in the emission angle range in the X-axis direction. Here, if the second light reflecting portion 36 is selectively provided in the fourth region A4 on the second opposite main surface 21C, it is necessary to turn on both the first LED 26 and the second LED 20 in order to obtain light whose emission angle range is not limited in the X-axis direction. However, in that case, there is a risk that a dark portion may be visually recognized between the light emitted from the portion of the first light guide plate light output main surface 27B overlapping with the first region A1 and the light emitted from the portion of the second light guide plate light output main surface 21B overlapping with the fourth region A4. In this respect, in order to obtain light whose output angle range is not limited in the X-axis direction, the first LED 26 may be turned off and the second LED 20 may be turned on, so that the above-mentioned dark portion is less likely to be visually recognized. In addition, in this embodiment, the first region A1 and the third region A3 are arranged to overlap with the first display portion AA1 of the display area AA, and the second region A2 and the fourth region A4 are arranged to overlap with the second display portion AA2 of the display area AA. Therefore, while the passenger car is stopped, the second LED 20 and the third LED 13 are turned on and the first LED 26 is turned off. Since the light emitted from the backlight device 12 has no restriction on the emission angle range in the X-axis direction over almost the entire area, both the image displayed on the first display unit AA1 in front of the driver's seat and the image displayed on the second display unit AA2 in front of the passenger seat can be viewed from both the driver's seat and the passenger seat.

[0084] In this embodiment, the second light guide plate 21 is disposed with the first light guide plate 27 sandwiched between it and the first louver 18, as shown in FIG. 1. Here, for example, if the second region A2 of the first opposite principal surface 27C of the first light guide plate 27 is scratched, the light propagating through the first light guide plate 27 may be emitted from a portion of the first light guide plate light output principal surface 27B that overlaps with the second region A2 due to the scratch. Even in this case, since the second opposite principal surface 21C of the second light guide plate 21 is disposed facing the first light guide plate light output principal surface 27B of the first light guide plate 27, the light emitted from the portion of the first light guide plate light output principal surface 27B that overlaps with the second region A2 can be made difficult to be emitted from the second opposite principal surface 21C by being reflected by the second light guide plate 21. In particular, in this embodiment, the fourth light guide plate lens 22, which is a lenticular lens, is provided on the second light guide plate light output principal surface 21B of the second light guide plate 21, so that the light output from the portion of the first light guide plate light output principal surface 27B that overlaps with the second area A2 can be satisfactorily reflected toward the rear side by the fourth light guide plate lens 22. This makes it possible to prevent the light emitted from the first LED 26 from being inadvertently supplied to the second display section AA2 of the display area AA when the first LED 26 and the third LED 13 are turned on and the second LED 20 is turned off.

[0085] As shown in Fig. 5, the sixth light guide plate lenses 24 constituting the second light reflecting section 36 are provided in the third region A3 and the fourth region A4 on the second opposite principal surface 21C. In the following, when the sixth light guide plate lenses 24 and the sixth light guide plate inclined surface 24A are to be distinguished from each other, the subscript α is added to the reference numeral of the lens arranged in the fourth region A4, and the subscript β is added to the reference numeral of the lens arranged in the third region A3. When the sixth light guide plate lenses 24 and the sixth light guide plate inclined surface 24A are to be collectively referred to without distinction, the subscript is not added to the reference numeral. Among the sixth light guide plate lenses 24 constituting the second light reflecting section 36, the sixth light guide plate lens 24α arranged in the fourth region A4 has a sixth light guide plate inclined surface (first inclined surface) 24Aα that is inclined from the side opposite to the second LED 20 toward the second LED 20 in the X-axis direction. In contrast, among the multiple sixth light guide plate lenses 24, the sixth light guide plate lens 24β arranged in the third region A3 has a sixth light guide plate inclined surface (second inclined surface) 24Aβ that is inclined from the side opposite the second LED 20 in the X-axis direction toward the second LED 20. Since these sixth light guide plate lenses 24α, 24β have the same structure, the inclination angles θ8, θ11 that these sixth light guide plate inclined surfaces 24Aα, 24Aβ make with respect to the X-axis direction are equal.

[0086] According to this configuration, when the second LED 20 is turned on, the light incident on the second light guide plate 21 hits the sixth light guide plate inclined surface 24Aα of the sixth light guide plate lens 24α in the fourth region A4 of the second opposite principal surface 21C, and hits the sixth light guide plate inclined surface 24Aβ of the sixth light guide plate lens 24β in the third region A3. The light that hits the sixth light guide plate inclined surface 24Aα is reflected and emitted from a portion of the second light guide plate light output principal surface 21B that overlaps with the fourth region A4. The emitted light contains more light that travels in the direction opposite to the second LED 20 side in the X-axis direction with respect to the front direction than light that travels toward the second LED 20 side in the X-axis direction. The light that hits the sixth light guide plate inclined surface 24Aβ is reflected and emitted from a portion of the second light guide plate light output principal surface 21B that overlaps with the third region A3. The emitted light includes more light traveling in the direction opposite to the second LED 20 side in the X-axis direction with respect to the front direction than light traveling toward the second LED 20 side in the X-axis direction. Therefore, it is possible to supply emitted light having a luminance angle distribution in which the peak luminance of the emitted light from the portion of the second light guide plate light output main surface 21B overlapping with the fourth region A4 and the peak luminance of the emitted light from the portion overlapping with the third region A3 are both biased toward the side opposite to the second LED 20 side in the X-axis direction. This makes it possible to ensure sufficient luminance of the emitted light in the direction inclined toward the side opposite to the second LED 20 side in the X-axis direction with respect to the front direction.

[0087] Moreover, as shown in FIG. 5, the sixth light guide plate inclined surface 24Aβ has the same inclination as the sixth light guide plate inclined surface 24Aα. Therefore, when the second LED 20 is turned on, the luminance angle distribution of the light emitted from the second light guide plate light output main surface 21B tends to be the same. This makes it difficult for localized dark areas to occur near the boundary between the portion of the second light guide plate light output main surface 21B overlapping with the third region A3 and the portion of the second light guide plate light output main surface 21B overlapping with the fourth region A4. Furthermore, since the sixth light guide plate inclined surface 24Aα and the sixth light guide plate inclined surface 24Aβ have the same inclination angles θ8 and θ11 with respect to the X-axis direction, the luminance angle distribution of the light emitted from the second light guide plate light output main surface 21B when the second LED 20 is turned on is highly uniform. This makes it more difficult for localized dark areas to occur near the boundary between the portion of the second light guide plate's light-emitting main surface 21B that overlaps with the third region A3 and the portion that overlaps with the fourth region A4.

[0088] 5, the plurality of ninth light guide plate lenses 30 constituting the first light reflecting portion 35 have a ninth light guide plate inclined surface (third inclined surface) 30A that is inclined from the side opposite to the first LED 26 toward the first LED 26 in the X-axis direction. In this manner, the ninth light guide plate inclined surface 30A has the same inclination as the sixth light guide plate inclined surface 24Aα and the sixth light guide plate inclined surface 24Aβ. Therefore, the luminance angle distribution of the light emitted from the first light guide plate light output principal surface 27B when the second LED 20 is turned off and the first LED 26 is turned on tends to be the same as the luminance angle distribution of the light emitted from the second light guide plate light output principal surface 21B when the first LED 26 is turned off and the second LED 20 is turned on. This makes it less likely that an incongruity will occur in the appearance of the light emitted from the backlight device 12 when the second LED 20 is turned off and the first LED 26 is turned on, and when the first LED 26 is turned off and the second LED 20 is turned on.

[0089] Next, a circuit configuration for controlling the driving of the above-mentioned liquid crystal panel 11 and backlight device 12 will be described with reference to the block diagram shown in FIG. 12. As shown in FIG. 12, the liquid crystal display device 10 has a control unit 50 for controlling the driving of the liquid crystal panel 11 and the backlight device 12. The control unit 50 includes a video signal processing circuit 51, a panel control circuit 52, and a backlight control circuit (light source control unit) 53. The video signal processing circuit 51 processes a video signal supplied from an external host system and outputs the processed video signal. The panel control circuit 52 writes an image based on the processed video signal output from the video signal processing circuit 51 to the liquid crystal panel 11. When the liquid crystal display device 10 includes a gate driver and a source driver for writing an image to the liquid crystal panel 11, the panel control circuit 52 controls the driving of the gate driver and the source driver. The backlight control circuit 53 controls the first LED 26, the second LED 20, and the third LED 13 to adjust the amount of light emitted by the first LED 26, the second LED 20, and the third LED 13, etc. The backlight control circuit 53 can perform, for example, PWM (Pulse Width Modulation) dimming when controlling the first LED 26, the second LED 20, and the third LED 13. When the liquid crystal display device 10 includes an LED driver that drives the first LED 26, the second LED 20, and the third LED 13, the backlight control circuit 53 controls the driving of the LED driver.

[0090] As shown in FIG. 12, the control unit 50 according to the present embodiment can switch between a display in a first display mode (first mode) and a display in a second display mode (second mode) based on a display mode switching signal supplied from an external host system. In the first display mode, the display image of the first display unit AA1 in the display area AA is visible from both the driver's seat and the passenger seat, whereas the display image of the second display unit AA2 in the display area AA is visible from the passenger seat but is restricted from the driver's seat, and can be said to be a "partial privacy mode". In the second display mode, the display image of the first display unit AA1 in the display area AA and the display image of the second display unit AA2 in the display area AA are visible from both the driver's seat and the passenger seat, and can be said to be a "full screen public mode". The running speed of the passenger vehicle in which the liquid crystal display device 10 is mounted can be used as a trigger for inputting the display mode switching signal. For example, the external host system can supply a display mode switching signal to the control unit 50 at each timing when the traveling speed of the passenger vehicle exceeds a threshold value and at each timing when the traveling speed falls below the threshold value.

[0091] Specifically, when the traveling speed of the passenger vehicle exceeds a threshold value, the control unit 50 performs display in the first display mode based on a display mode switching signal supplied from an external host system. When displaying in the first display mode, the backlight control circuit 53 included in the control unit 50 performs control to turn on the first LED 26 and the third LED 13 and turn off the second LED 20, as shown in Figs. 1 and 5. In this way, the emission angle range of the light emitted from the part of the backlight device 12 that overlaps with the first area A1 and the third area A3 is not limited in the X-axis direction. As a result, the image displayed on the first display unit AA1 in front of the driver's seat and overlapping with the first area A1 and the third area A3 can be viewed from both the driver's seat and the passenger seat. The emission angle range of the light emitted from the part of the backlight device 12 that overlaps with the second area A2 and the fourth area A4 is limited in the X-axis direction. As a result, the image displayed on the second display unit AA2, which is located in front of the passenger seat and overlaps with the second area A2 and the fourth area A4, can be viewed from the passenger seat but cannot be viewed from the driver's seat.

[0092] On the other hand, when the traveling speed of the passenger vehicle falls below the threshold, the control unit 50 performs display in the second display mode based on a display mode switching signal supplied from an external host system. When displaying in the second display mode, the backlight control circuit 53 included in the control unit 50 performs control to turn on the second LED 20 and the third LED 13 and turn off the first LED 26. In this way, the emission angle range of the light emitted from the backlight device 12 is not limited in the X-axis direction over almost the entire area. As a result, both the image displayed on the first display unit AA1 in front of the driver's seat and overlapping with the first area A1 and the third area A3, and the image displayed on the second display unit AA2 in front of the passenger's seat and overlapping with the second area A2 and the fourth area A4 can be viewed from both the driver's seat and the passenger's seat.

[0093] In both the first display mode and the second display mode, the backlight control circuit 53 included in the control unit 50 drives the third LEDs 13 by dividing them into two groups as follows. Specifically, the third LEDs 13 arranged along the X-axis direction (first direction) are divided into a group of a fourth LED (fourth light source) 13α arranged to face a portion of the third light guide plate 14 overlapping with the first region A1 and the third region A3, and a group of a fifth LED (fifth light source) 13β arranged to face a portion of the third light guide plate 14 overlapping with the second region A2 and the fourth region A4, as shown in Figs. 1 and 3. In the following, when the third LEDs 13 are to be distinguished from one another, the subscript α is added to the reference numeral of the "fourth LED" and the subscript β is added to the reference numeral of the "fifth LED", and when the third LEDs 13 are to be collectively referred to without distinction, the subscript is not added to the reference numeral.

[0094] 1, 3 and 12, the backlight control circuit 53 controls the amount of light emitted per unit time of the fourth LED 13α to be greater than the amount of light emitted per unit time of the fifth LED 13β, even if the display grayscale of the first display section AA1 is the same as the display grayscale of the second display section AA2. The "display grayscale of the first display section AA1" referred to here is the same as the amount of light emitted from the portion of the backlight device 12 that overlaps with the first area A1 and the third area A3. Similarly, the "display grayscale of the second display section AA2" referred to here is the same as the amount of light emitted from the portion of the backlight device 12 that overlaps with the second area A2 and the fourth area A4. In addition, when the display gradation in the second display section AA2 is lower than the display gradation in the first display section AA1, the backlight control circuit 53 may control the amount of light emitted per unit time of the fourth LED 13α to be equal to the amount of light emitted per unit time of the fifth LED 13β.

[0095] As shown in Fig. 1 and Fig. 3, when the light emitted from the third LEDs 13 is emitted from the third light guide plate light output main surface 14B of the third light guide plate 14, it passes through the first light guide plate 27 and the second light guide plate 21 and is emitted to the outside. Here, the light emitted from the portion of the third light guide plate light output main surface 14B overlapping with the second region A2 and the fourth region A4 may be refracted by the second light reflecting portion 36 when it enters the fourth region A4 of the second opposite main surface 21C of the second light guide plate 21. However, when the above-mentioned emitted light enters the second region A2 of the first opposite main surface 27C of the first light guide plate 27, the first light reflecting portion 35 is not formed in the second region A2 and the second region A2 is substantially flat, so that the light is hardly refracted. In contrast, the light emitted from the portion of the third light guide plate light output principal surface 14B overlapping with the first region A1 and the third region A3 is refracted by the first light reflecting portion 35 when it enters the second region A2 of the first opposite principal surface 27C of the first light guide plate 27, and may be refracted by the second light reflecting portion 36 when it enters the fourth region A4 of the second opposite principal surface 21C of the second light guide plate 21. For this reason, the light emitted from the portion of the third light guide plate light output principal surface 14B overlapping with the first region A1 and the third region A3 tends to be more easily diffused than the light emitted from the portion overlapping with the second region A2 and the fourth region A4, and the amount of light emitted from the portion of the backlight device 12 overlapping with the first region A1 and the third region A3 tends to be less than the amount of light emitted from the portion overlapping with the second region A2 and the fourth region A4. In this regard, even if the display gradation in the first display section AA1 and the display gradation in the second display section AA2 are the same, the backlight control circuit 53 makes the amount of light emitted per unit time of the fourth LED 13α that supplies light to the portion of the third light guide plate light output main surface 14B that overlaps with the first region A1 and the third region A3 greater than the amount of light emitted per unit time of the fifth LED 13β that supplies light to the portion of the third light guide plate light output main surface 14B that overlaps with the second region A2 and the fourth region A4. This makes it difficult for a difference to occur between the amount of light emitted from the portion of the backlight device 12 that overlaps with the first region A1 and the third region A3 and the amount of light emitted from the portion of the backlight device 12 that overlaps with the second region A2 and the fourth region A4.

[0096] Next, in the liquid crystal display device 10 having the above-mentioned configuration, in order to obtain knowledge regarding how the light distribution of the backlight device 12 changes when the display is performed in the first display mode and when the display is performed in the second display mode, a demonstration experiment 1 was performed. In this demonstration experiment 1, the liquid crystal display device 10 described in the preceding paragraph was used, and the luminance of the light emitted from the backlight device 12 was measured in two cases: when the backlight control circuit 53 was controlled to turn on the first LED 26 and the third LED 13 and turn off the second LED 20 in order to perform display in the first display mode, and when the backlight control circuit 53 was controlled to turn on the second LED 20 and the third LED 13 and turn off the first LED 26 in order to perform display in the second display mode, and a graph was created regarding the light distribution (luminance angle distribution) in the X-axis direction. The luminance was measured in the part of the backlight device 12 overlapping with the first region A1 and the third region A3 and in the part overlapping with the second region A2 and the fourth region A4.

[0097] The experimental results of the light distribution in the demonstration experiment 1 are shown in Fig. 13 and Fig. 14. In the graphs of the light distribution shown in Fig. 13 and Fig. 14, the horizontal axis represents the angle (unit: "°") in the X-axis direction with respect to the front direction (Z-axis direction), and the vertical axis represents the luminance (unit: "cd / m 2"). Among the positive and negative symbols attached to the angles on the horizontal axis in Figs. 13 and 14, "- (minus)" means the left side in the X-axis direction with respect to the reference 0° (front direction) when the backlight device 12 is viewed from the front, and "+ (plus)" means the right side in the X-axis direction with respect to the reference 0° (front direction) when the backlight device 12 is viewed from the front. Fig. 13 shows the light distribution when the first LED 26 and the third LED 13 are turned on and the second LED 20 is turned off (second display mode). Fig. 13 also shows the light distribution of the emitted light from the portion of the backlight device 12 that overlaps with the first region A1 and the third region A3 when the second LED 20 and the third LED 13 are turned on and the first LED 26 is turned off (first display mode). FIG. 14 shows the light distribution of the emitted light from the portion of the backlight device 12 that overlaps with the second region A2 and the fourth region A4 when the second LED 20 and the third LED 13 are turned on and the first LED 26 is turned off (first display mode).

[0098] The experimental results of the demonstration experiment 1 will be described. In FIG. 13, the peak luminance is approximately 0°, and the light distribution is asymmetrical with the emitted light being biased toward the "-" side. Specifically, the light distribution in FIG. 13 has the emitted light biased toward the left side in the X-axis direction, that is, toward the opposite side to the second LED 20, and the emission angle range is approximately -80° to +20°. In FIG. 14, the peak luminance is approximately 0°, and the light distribution is approximately symmetrical. Specifically, the light distribution in FIG. 14 has an emission angle range of approximately ±10°. This result reflects that the light emitted from the third light guide plate 14 when the third LED 13 is turned on is limited to an emission angle range of approximately ±10° by the first louver 18. In FIG. 14, the emission angle range is extremely narrower than in FIG. 13. In FIG. 13, the output angle range is relatively wider than in FIG. 14, and it can be said that the output angle range is not so limited.

[0099] The viewing angle characteristics of the first display section AA1 and the second display section AA2 in the display region AA of the liquid crystal display device 10 will be described with reference to FIG. 15. FIG. 15 shows the visible range and the light blocking range based on the light emission angle range in each of the first display section AA1 and the second display section AA2. In the first display section AA1, the visible range is about -80° to +20° in both the first display mode and the second display mode, which matches the light distribution shown in FIG. 13. In the second display section AA2, the visible range is about -80° to +20° in the second display mode, which matches the light distribution shown in FIG. 13, but is about -10° to +10° in the first display mode, which matches the light distribution shown in FIG. 14. Therefore, when the liquid crystal display device 10 performs display in the second display mode, the image displayed in the first display section AA1 and the image displayed in the second display section AA2 can be viewed from both the driver's seat and the passenger's seat. On the other hand, when the liquid crystal display device 10 is displayed in the first display mode, the image displayed on the first display unit AA1 and the image displayed on the second display unit AA2 can each be seen from the passenger seat, whereas from the driver's seat, while the image displayed on the first display unit AA1 can be seen, the image displayed on the second display unit AA2 is almost impossible to see.

[0100] Next, in the liquid crystal display device 10 having the above configuration, in order to obtain knowledge regarding how the luminance distribution of the backlight device 12 changes when displaying in the first display mode and when displaying in the second display mode, a demonstration experiment 2 was performed. In this demonstration experiment 2, the liquid crystal display device 10 described in the paragraph preceding the demonstration experiment 1 was used, and the luminance of the light emitted from the backlight device 12 was measured in two cases: when the backlight control circuit 53 was controlled to turn on the first LED 26 and the third LED 13 and to turn off the second LED 20 in order to display in the first display mode, and when the backlight control circuit 53 was controlled to turn on the second LED 20 and the third LED 13 and to turn off the first LED 26 in order to display in the second display mode. Specifically, the luminance was measured at every predetermined distance from the left end position in the X-axis direction of the backlight device 12 through the center position to the right end position, and at each position, the luminance of the light emitted from the backlight device 12 at an angle of 0° (front direction) and the luminance of the light emitted from the backlight device 12 at an angle of -45° (diagonally leftward in the X-axis direction) were measured. Based on the measurement results, a diagram was created showing the luminance distribution by shading for the luminance of the light emitted from the backlight device 12 at an angle of 0° and the luminance of the light emitted from the backlight device 12 at an angle of -45°, and a graph showing the luminance distribution in the X-axis direction was created.

[0101] The experimental results of Demonstration Experiment 2 are as shown in Figures 16 to 23. Figures 16, 18, 20 and 22 show diagrams relating to luminance distribution. In Figures 16, 18, 20 and 22, the level of luminance is represented by shading, and a legend relating to the luminance shading (higher luminance at the top and lower luminance at the bottom in the legend) is shown. Figures 17, 19, 21 and 23 show graphs relating to luminance distribution. In Figures 17, 19, 21 and 23, the horizontal axis represents position in the X-axis direction (unit: mm), and the vertical axis represents luminance (unit: cd / m 2"). In the "position in the X-axis direction" of the horizontal axis in Figs. 17, 19, 21, and 23, the central position in the X-axis direction of the backlight device 12 is set as the reference position (0 mm). Among the positive and negative signs attached to the "position in the X-axis direction" of the horizontal axis in Figs. 17, 19, 21, and 23, "- (minus)" means the left side in the X-axis direction with respect to the reference position described above, that is, the first display unit AA1, and "+ (plus)" means the right side in the X-axis direction with respect to the reference position described above, that is, the second display unit AA2. In the horizontal axes in Figs. 17, 19, 21, and 23, the position of "-150 mm" coincides with the left end position in the X-axis direction, and the position of "+150 mm" coincides with the right end position in the X-axis direction.

[0102] 16 to 19 are experimental results when the second LED 20 and the third LED 13 are turned on and the first LED 26 is turned off (second display mode). Among these, FIGS. 16 and 17 are experimental results when the luminance of light emitted from the backlight device 12 at an angle of 0° is measured, and FIGS. 18 and 19 are experimental results when the luminance of light emitted from the backlight device 12 at an angle of -45° is measured. FIGS. 20 to 23 are experimental results when the first LED 26 and the third LED 13 are turned on and the second LED 20 is turned off (first display mode). FIGS. 20 and 21 are experimental results when the luminance of light emitted from the backlight device 12 at an angle of 0° is measured, and FIGS. 22 and 23 are experimental results when the luminance of light emitted from the backlight device 12 at an angle of -45° is measured.

[0103] The experimental results of the demonstration experiment 2 will be described. According to Fig. 16 to Fig. 19, when the display is performed in the second display mode, the luminance distribution of the light emitted from the backlight device 12 at an angle of 0° and the luminance distribution of the light emitted from the backlight device 12 at an angle of -45° both have a generally high luminance uniformity. Therefore, when the display is performed in the second display mode, it can be said that the image displayed on the first display unit AA1 and the image displayed on the second display unit AA2 are both visible from the driver's seat with a sufficiently high luminance, and the image displayed on the second display unit AA2 is visible from the passenger's seat with a sufficiently high luminance.

[0104] 20 and 21, it can be seen that the luminance distribution of the light emitted from the backlight device 12 at an angle of 0° in the case of display in the first display mode has a high luminance uniformity equivalent to that in the case of display in the second display mode. On the other hand, according to Fig. 22 and Fig. 23, it can be seen that the luminance distribution of the light emitted from the backlight device 12 at an angle of -45° in the case of display in the first display mode is biased. Therefore, it can be said that, in the case of display in the first display mode, the image displayed on the first display unit AA1 is visible with a sufficiently high luminance from the driver's seat, and the image displayed on the second display unit AA2 is visible with a sufficiently high luminance from the passenger's seat, but the image displayed on the second display unit AA2 is almost invisible from the driver's seat.

[0105] As described above, the backlight device (illumination device) 12 of the present embodiment includes a first LED (first light source) 26, a first light guide plate 27 having at least a part of an outer peripheral end face configured as a first light entering end face (first end face) 27A facing the first LED 26 and into which light is incident, one main face configured as a first light guide plate light exiting main face (first main face) 27B that emits light, and the other main face configured as a first opposite main face (second main face) 27C, a second LED (second light source) 20, and at least a part of an outer peripheral end face configured as a second light entering end face (second end face) 21A facing the second LED 20 and into which light is incident, and one main face configured as a first opposite main face (second main face) 27C. a second light guide plate 21 having a second opposite principal surface (fourth principal surface) 21C and a third LED (third light source) 13, a third light input end surface (light incident surface) 14A facing the third LED 13 and into which light is input, and a third light guide plate (optical member) 14 having a third light output principal surface (fifth principal surface) 14B from which light is output; and a first louver (first light guide plate) 14 having one principal surface serving as a first louver output principal surface (sixth principal surface) 18B and a first louver input principal surface (seventh principal surface) 18A arranged facing the third light guide plate light output principal surface 14B. The first light guide plate 27 and the second light guide plate 21 have their main surfaces overlapping each other and are disposed on the opposite side of the first louver 18 from the third light guide plate 14 side, and the first louver 18 has at least two first light-shielding portions 18C that are disposed at an interval in a first direction including a direction from the first LEDs 26 toward the first light guide plate 27 and that block light, and a first light-transmitting portion 18D that is disposed between the two first light-shielding portions 18C and that transmits light. A first light reflecting portion 35 that reflects light and promotes output from the first light guide plate light output main surface 27B is provided on the first opposite main surface 27C, and a second reflecting portion 35 that reflects light and promotes output from the first light guide plate light output main surface 27B is provided on the first opposite main surface 27C. A second light reflecting portion 36 that reflects light to promote emission from the second light guide plate light output main surface 21B is provided on the opposing main surface 21C, and when the first opposing main surface 27C is divided into a first region A1 and a second region A2 adjacent to the first region A1 in the first direction, the first light reflecting portion 35 is selectively provided in the first region A1 on the first opposing main surface 27C, and when the second opposing main surface 21C is divided into a third region A3 overlapping with the first region A1 and a fourth region A4 overlapping with the second region A2, the second light reflecting portion 36 is provided in at least the fourth region A4 on the second opposing main surface 21C.

[0106] The light emitted from the first LED 26 and incident on the first light entering end surface 27A of the first light guide plate 27 propagates within the first light guide plate 27 and is reflected by the first light reflecting portion 35 provided on the first opposite principal surface 27C, so that the light is emitted from the first light guide plate light exiting principal surface 27B. Since the first light reflecting portion 35 is selectively provided in the first region A1 on the first opposite principal surface 27C, the light emitted from the first LED 26 is emitted from the portion of the first light guide plate light exiting principal surface 27B that overlaps with the first region A1, but is not emitted from the portion that overlaps with the second region A2.

[0107] The light emitted from the second LED 20 and incident on the second light entering end surface 21A of the second light guide plate 21 propagates within the second light guide plate 21 and is reflected by the second light reflecting portion 36 provided on the second opposite principal surface 21C, and is emitted from the second light guide plate light exiting principal surface 21B. Since the second light reflecting portion 36 is provided in at least the fourth region A4 on the second opposite principal surface 21C, the light emitted from the second LED 20 exits from at least a portion of the second light guide plate light exiting principal surface 21B that overlaps with the fourth region A4.

[0108] When the light emitted from the third LED 13 is incident on the third light-entering end surface 14A of the third light guide plate 14, it is emitted from the third light-exiting plate light-exiting main surface 14B and is incident on the first louver light-entering main surface 18A of the first louver 18. The light incident on the first louver light-entering main surface 18A of the first louver 18 passes through the first light-transmitting portion 18D arranged between the two first light-shielding portions 18C, and is emitted from the first louver light-exiting main surface 18B. The emission angle of the light emitted from the first louver light-exiting main surface 18B is limited by the two first light-shielding portions 18C. The light emitted from the first louver light-exiting main surface 18B passes through the first light guide plate 27 and the second light guide plate 21 whose main surfaces overlap each other. The light emitted from first louver light-emitting main surface 18B is unlikely to be emitted outside the limited angular range because the angular range is limited by first light-shielding portion 18C of first louver 18. In this manner, by turning on third LED 13, it is possible to selectively emit light within the limited angular range.

[0109] For example, when the first LED 26 and the third LED 13 are turned on and the second LED 20 is turned off, the emitted light of the backlight device 12 includes light emitted in a limited angle range from the first louver light-emitting main surface 18B of the first louver 18 and light selectively emitted from a portion overlapping with the first region A1 on the first light-guiding plate light-emitting main surface 27B of the first light-guiding plate 27. As a result, in this case, the emission angle range of the light emitted from the portion overlapping with the first region A1 and the third region A3 of the backlight device 12 is not so limited in the first direction, but the emission angle range of the light emitted from the portion overlapping with the second region A2 and the fourth region A4 of the backlight device 12 is limited in the first direction.

[0110] The second light reflecting portion 36 is provided across the third region A3 and the fourth region A4 on the second opposite principal surface 21C. The light emitted from the second LED 20 and incident on the second light-entering end surface 21A of the second light guide plate 21 propagates through the second light guide plate 21 and is reflected by the second light reflecting portion 36 provided on the second opposite principal surface 21C, and is emitted from the second light guide plate light-exiting principal surface 21B. Since the second light reflecting portion 36 is provided across the third region A3 and the fourth region A4 on the second opposite principal surface 21C in the first direction, the light emitted from the second LED 20 is emitted across the portion overlapping with the third region A3 and the portion overlapping with the fourth region A4 on the second light guide plate light-exiting principal surface 21B. For example, if the second LED 20 and the third LED 13 are turned on and the first LED 26 is turned off, the emitted light of the backlight device 12 includes light emitted in a limited angle range from the first louver light-emitting main surface 18B of the first louver 18 and light emitted over a portion overlapping with the third region A3 and a portion overlapping with the fourth region A4 on the second light-guiding plate light-emitting main surface 21B of the second light-guiding plate 21. As a result, in this case, the emitted light of the backlight device 12 is not so limited in the emission angle range in the first direction. Here, if the second light reflecting portion 36 is selectively provided in the fourth region A4 on the second opposite main surface 21C, it is necessary to turn on both the first LED 26 and the second LED 20 in order to obtain light whose emission angle range in the first direction is not substantially limited. In that case, however, there is a risk that a dark area will be visually recognized between the light emitted from the portion of the first light guide plate light-emitting principal surface 27B that overlaps with the first region A1 and the light emitted from the portion of the second light guide plate light-emitting principal surface 21B that overlaps with the fourth region A4. In this regard, in order to obtain light whose emission angle range in the first direction is not substantially limited, it is sufficient to turn on the second LED 20 while turning off the first LED 26, so that such a dark area will be less likely to be visually recognized.

[0111] The first light reflecting portion 35 is composed of a plurality of ninth light guide plate lenses (first lenses) 30 arranged in a line along the first direction on the first opposite principal surface 27C, and the second light reflecting portion 36 is composed of a plurality of sixth light guide plate lenses (second lenses) 24 arranged in a line along the first direction on the second opposite principal surface 21C, and among the plurality of sixth light guide plate lenses 24, at least the sixth light guide plate lenses 24α arranged in the fourth region A4 have a sixth light guide plate inclined surface (first inclined surface) 24Aα that is inclined rising from the side opposite to the second LED 20 toward the second LED 20 side in the first direction. The light emitted from the second LED 20 and incident on the second light incident end surface 21A of the second light guide plate 21 hits the sixth light guide plate inclined surface 24Aα of the sixth light guide plate lens 24α arranged in at least the fourth region A4 of the second opposite principal surface 21C during the process of propagating through the second light guide plate 21. The light that hits the sixth light guide plate inclined surface 24Aα, which has an inclination that rises from the opposite side of the second LED 20 in the first direction in the second light guide plate 21 toward the second LED 20 side, is reflected and emitted from at least a portion of the second light guide plate light output main surface 21B that overlaps with the fourth region A4. The emitted light from at least a portion of the second light guide plate light output main surface 21B that overlaps with the fourth region A4 contains more light that travels toward the opposite side of the second LED 20 side in the first direction with respect to the normal direction of the second light guide plate light output main surface 21B, i.e., the front direction, than light that travels toward the second LED 20 side in the first direction. Therefore, when the second LED 20 is turned on, it is possible to supply emitted light with a luminance angle distribution in which the peak luminance of the emitted light from at least a portion of the second light guide plate light output main surface 21B that overlaps with the fourth region A4 is biased toward the opposite side of the second LED 20 side in the first direction. This makes it possible to ensure sufficient brightness of the emitted light in a direction inclined with respect to the front direction.

[0112] Moreover, among the sixth light guide plate lenses 24, the sixth light guide plate lens 24β arranged in the third region A3 has a sixth light guide plate inclined surface (second inclined surface) 24Aβ that is inclined from the side opposite to the second LED 20 toward the second LED 20 in the first direction. In this manner, the sixth light guide plate inclined surface 24Aβ has the same inclination as the sixth light guide plate inclined surface 24Aα. Therefore, when the second LED 20 is turned on, the luminance angle distribution of the light emitted from the second light guide plate light output principal surface 21B tends to be the same. This makes it difficult for a local dark area to occur near the boundary between the part of the second light guide plate light output principal surface 21B that overlaps with the third region A3 and the part that overlaps with the fourth region A4.

[0113] Moreover, the sixth light guide plate inclined surface 24Aα and the sixth light guide plate inclined surface 24Aβ have the same inclination angles θ8 and θ11 with respect to the first direction. The uniformity of the luminance angle distribution of the light emitted from the second light guide plate light-emitting principal surface 21B when the second LED 20 is turned on is increased. This makes it more difficult for localized dark areas to occur near the boundary between the portion of the second light guide plate light-emitting principal surface 21B that overlaps with the third region A3 and the portion that overlaps with the fourth region A4.

[0114] In addition, the positional relationship of the first LED 26 with respect to the first light guide plate 27 in the first direction is the same as the positional relationship of the second LED 20 with respect to the second light guide plate 21 in the first direction, and the multiple ninth light guide plate lenses 30 have a ninth light guide plate inclined surface (third inclined surface) 30A that is inclined from the opposite side to the first LED 26 toward the first LED 26 side in the first direction. In this manner, the ninth light guide plate inclined surface 30A has the same inclination as the sixth light guide plate inclined surface 24Aα. Therefore, the luminance angle distribution of the light emitted from the first light guide plate light output main surface 27B when the second LED 20 is turned off and the first LED 26 is turned on tends to be the same as the luminance angle distribution of the light emitted from the second light guide plate light output main surface 21B when the first LED 26 is turned off and the second LED 20 is turned on. This makes it less likely that an incongruity will arise in the appearance of the light emitted from the backlight device 12 when the second LED 20 is turned off and the first LED 26 is turned on, and when the first LED 26 is turned off and the second LED 20 is turned on.

[0115] The backlight control circuit 53 also includes a backlight control circuit (light source control unit) that controls the driving of the first LED 26, the second LED 20, and the third LED 13. The backlight control circuit 53 switches between a first mode in which the first LED 26 and the third LED 13 are turned on and the second LED 20 is turned off, and a second mode in which the second LED 20 and the third LED 13 are turned on and the first LED 26 is turned off, based on an input of a switching signal. When the backlight control circuit 53 controls in the first mode, the first LED 26 and the third LED 13 are turned on and the second LED 20 is turned off, so that the emission angle range of the light emitted from the portion of the backlight device 12 that overlaps with the first region A1 and the third region A3 is not so limited in the first direction, but the emission angle range of the light emitted from the portion of the backlight device 12 that overlaps with the second region A2 and the fourth region A4 is limited in the first direction. When the backlight control circuit 53 performs control in the second mode, the second LED 20 and the third LED 13 are turned on and the first LED 26 is turned off, so that the emission angle range of the light emitted from the backlight device 12 in the first direction is not significantly limited.

[0116] The second light guide plate 21 is disposed with the first light guide plate 27 sandwiched between it and the first louver 18. If the second region A2 of the first opposite main surface 27C of the first light guide plate 27 is scratched, the light propagating through the first light guide plate 27 may be emitted from the first light guide plate light output main surface 27B due to the scratch. Even in this case, the second light guide plate 21 is disposed so that the second opposite main surface 21C faces the first light guide plate light output main surface 27B of the first light guide plate 27. Therefore, the light emitted from the portion of the first light guide plate light output main surface 27B that overlaps with the second region A2 is reflected by the second light guide plate 21, making it difficult for the light to be emitted from the second opposite main surface 21C. This makes it possible to suppress inadvertent emission of light.

[0117] The optical member also includes a third light guide plate 14, the third light entering end surface 14A of which is formed by at least a part of the outer peripheral end surface, and the third light entering end surface 14A is disposed opposite the third LED 13. When the third LED 13 is turned on, light enters the third light entering end surface 14A of the outer peripheral end surface of the third light guide plate 14, propagates through the third light guide plate 14, and then exits from the third light exiting main surface 14B of the third light guide plate.

[0118] The light guide plate 14 also includes a backlight control circuit 53 that controls the driving of the first LED 26, the second LED 20, and the third LED 13. The third light incident end surface 14A is composed of a portion of the outer peripheral end surface of the third light guide plate 14 that extends along the first direction. The third LEDs 13 are arranged in a line along the first direction. The third LEDs 13 include a fourth LED (fourth light source) 13α arranged opposite a portion of the third light guide plate 14 that overlaps with the first region A1 and the third region A3, and a fifth LED (fifth light source) 13β arranged opposite a portion of the third light guide plate 14 that overlaps with the second region A2 and the fourth region A4. The backlight control circuit 53 makes the amount of light emitted per unit time of the fourth LED 13α greater than the amount of light emitted per unit time of the fifth LED 13β. When the light emitted from the multiple third LEDs 13 is emitted from the third light guide plate light output main surface 14B of the third light guide plate 14, it passes through the first light guide plate 27 and the second light guide plate 21 and is emitted to the outside. Here, the light emitted from the portion of the third light guide plate light output main surface 14B overlapping with the second region A2 and the fourth region A4 may be refracted by the second light reflecting portion 36. In contrast, the light emitted from the portion of the third light guide plate light output main surface 14B overlapping with the first region A1 and the third region A3 may be refracted by both the first light reflecting portion 35 and the second light reflecting portion 36, and therefore tends to be more easily diffused than the light emitted from the portion overlapping with the second region A2 and the fourth region A4. In this regard, the backlight control circuit 53 makes the amount of light emitted per unit time of the fourth LED 13α, which supplies light to a portion of the third light guide plate's light output main surface 14B that overlaps with the first region A1 and the third region A3, greater than the amount of light emitted per unit time of the fifth LED 13β, which supplies light to a portion of the third light guide plate's light output main surface 14B that overlaps with the second region A2 and the fourth region A4. This makes it less likely that unevenness will occur in the amount of light emitted by the backlight device 12.

[0119] Moreover, the liquid crystal display device (display device) 10 according to this embodiment includes the above-described backlight device 12 and a liquid crystal panel (display panel) 11 that performs display using light from the backlight device 12. According to the liquid crystal display device 10 configured as above, the outgoing angle range of a part of the outgoing light is limited in the backlight device 12, which is suitable for diversifying the display mode.

[0120] <Embodiment 2> A second embodiment will be described with reference to Fig. 24 or 25. In this second embodiment, the first backlight unit 112U1 and the second backlight unit 112U2 are interchanged in the Z-axis direction. Note that a duplicated description of the structure, operation, and effects similar to those of the first embodiment will be omitted.

[0121] The first backlight unit 112U1 according to this embodiment is disposed on the back side of the diffusion sheet 112S as shown in FIG. 24. In contrast, the second backlight unit 112U2 is disposed on the back side of the first backlight unit 112U1 and on the front side of the third backlight unit 112U3. Therefore, the first light guide plate 127 constituting the first backlight unit 112U1 is disposed to sandwich the second light guide plate 121 constituting the second backlight unit 112U2 between the louver 118 constituting the third backlight unit 112U3 as shown in FIG. 25. With this configuration, when the first LED 126 is turned off and the second LED 120 is turned on, light is selectively emitted from a portion of the second light guide plate light output main surface 121B of the second light guide plate 121 that overlaps with the fourth region A4. This outgoing light is emitted to the outside without passing through first light guide plate 127, and therefore, refraction or the like by first light guide plate 127 is avoided.

[0122] As described above, according to this embodiment, first light guide plate 127 is disposed with second light guide plate 121 sandwiched between first light guide plate 127 and louver 118. When first LED 126 is turned off and second LED 120 is turned on, light is selectively emitted from a portion of second light guide plate light output main surface 121B of second light guide plate 121 that overlaps with fourth region A4. This emitted light is emitted to the outside without passing through first light guide plate 127, and therefore refraction or the like by first light guide plate 127 is avoided.

[0123] <Embodiment 3> A third embodiment will be described with reference to Fig. 26 or 27. In this third embodiment, a configuration of the third backlight unit 212U3 is changed from that of the first embodiment. Note that a duplicated description of the structure, operation, and effects similar to those of the first embodiment will be omitted.

[0124] The third backlight unit 212U3 according to this embodiment is a so-called direct type, as shown in Fig. 26. The third backlight unit 212U3 at least includes a louver 218 similar to that of the first embodiment, a plurality of third LEDs (third light sources) 38, an LED board (light source board) 39 on which the plurality of third LEDs 38 are mounted, and an optical member 40 that imparts an optical effect to the light emitted from the third LEDs 38.

[0125] As shown in Fig. 26 and Fig. 27, the third LED 38 is a so-called top-emitting type, which is surface-mounted on the LED substrate 39 and has a third light-emitting surface 38A facing the opposite side to the LED substrate 39 side (front side, optical member 40 side). The LED substrate 39 has a main surface parallel to and overlapping with each main surface of the liquid crystal panel 211 and each light guide plate 221, 227, etc. A plurality of third LEDs 38 are mounted on the main surface of the LED substrate 39 facing the front side, which serves as a mounting surface. Within the main surface on the front side of the LED substrate 39, a plurality of third LEDs 38 are arranged in a matrix at intervals in the X-axis direction and the Y-axis direction.

[0126] The optical member 40 includes four sheets stacked on top of each other in the Z-axis direction, as shown in Fig. 26. The main surfaces of the multiple optical members 40 are parallel to and overlap the main surfaces of the liquid crystal panel 211 and the light guide plates 221, 227, etc. The four optical members 40 are, in order from the back side, a diffusion plate (optical member) 40A, a diffusion sheet 40B, and two prism sheets 40C and 40D.

[0127] As shown in FIG. 26, the diffusion plate 40A is thicker than the other optical members 40B to 40D, and is configured by dispersing a large number of diffusion particles in a substantially transparent resin base material, and has a function of diffusing light passing through. The back main surface of the diffusion plate 40A faces the third light emitting surface 38A of the third LED 38, and serves as a light incident surface 40A1 into which light from the third LED 38 is incident. The front main surface of the diffusion plate 40A is a light exit surface (fifth main surface) 40A2 that emits light incident from the light incident surface 40A1 toward the front side. It can be said that the multiple third LEDs 38 are arranged in a plane so as to overlap with the light incident surface 40A1 and the light exit surface 40A2, which are the main surfaces of the diffusion plate 40A. The light exit surface 40A2 of the diffusion plate 40A is arranged facing the louver 218 through the other optical members 40B to 40D. When the light emitted from the third light-emitting surface 38A of the third LED 38 enters the light incident surface 40A1 of the diffusion plate 40A, the light is diffused by the diffusion particles and is emitted from the light exit surface 40A2 towards the front side.

[0128] As shown in Fig. 26, the diffusion sheet 40B is configured by dispersing a large number of diffusion particles for diffusing light in a substantially transparent synthetic resin base material. The two prism sheets 40C and 40D are configured by arranging a large number of prisms extending along the X-axis direction or the Y-axis direction on the main surface of the substantially transparent synthetic resin base material in a direction perpendicular to the extending direction (Y-axis direction or X-axis direction), and selectively provide a light collecting effect to incident light in the prism arrangement direction. The two prism sheets 40C and 40D are arranged so that the extending directions of the prisms (the prism arrangement directions) are perpendicular to each other.

[0129] In this embodiment, the backlight control circuit 53 (see FIG. 12) drives the multiple third LEDs 38 as follows. That is, the backlight control circuit 53 can control the amount of light emitted by each of the multiple third LEDs 38 shown in FIG. 26 and FIG. 27 and whether or not to light them up, depending on the display gradation of the image displayed in the display area AA of the liquid crystal panel 211. This makes it possible to realize so-called local dimming control, thereby improving contrast performance, etc.

[0130] Furthermore, in both the first display mode and the second display mode, the backlight control circuit 53 (see FIG. 12) drives the multiple third LEDs 38 divided into two groups as follows. Specifically, the multiple third LEDs 38 arranged in a matrix are divided into a multiple fourth LEDs (fourth light source) 38α arranged to overlap the first region A1 and the third region A3, and a multiple fifth LEDs (fifth light source) 38β arranged to overlap the second region A2 and the fourth region A4, as shown in FIG. 26 and FIG. 27. In the following, when the third LEDs 38 are to be distinguished, the subscript α is added to the reference character of the "fourth LED" and the subscript β is added to the reference character of the "fifth LED", and when they are to be collectively referred to without distinction, the subscript is not added to the reference character.

[0131] 26 and 27, the backlight control circuit (see FIG. 12) 53 controls the amount of light emitted per unit time of the fourth LED 38α to be greater than the amount of light emitted per unit time of the fifth LED 38β, even if the display grayscale of the first display unit AA1 is the same as the display grayscale of the second display unit AA2. Note that, when the display grayscale of the second display unit AA2 is lower than the display grayscale of the first display unit AA1, the backlight control circuit 53 may control the amount of light emitted per unit time of the fourth LED 38α to be equal to the amount of light emitted per unit time of the fifth LED 38β.

[0132] As shown in Fig. 26 and Fig. 27, when the light emitted from the plurality of third LEDs 38 is emitted from the light exit surface 40A2 of the diffusion plate 40A, it passes through the first light guide plate 227 and the second light guide plate 221 and is emitted to the outside. Here, the light emitted from the portion of the light exit surface 40A2 overlapping with the second region A2 and the fourth region A4 may be refracted by the second light reflecting portion 236 when it enters the fourth region A4 of the second opposite main surface 221C of the second light guide plate 221. However, when the above-mentioned emitted light enters the second region A2 of the first opposite main surface 227C of the first light guide plate 227, the first light reflecting portion 235 is not formed in the second region A2 and the second region A2 is almost flat, so that the light is hardly refracted. On the other hand, the light emitted from the portion of the light exit surface 40A2 overlapping with the first region A1 and the third region A3 is refracted by the first light reflecting portion 235 when it enters the second region A2 of the first opposite principal surface 227C of the first light guide plate 227, and may be refracted by the second light reflecting portion 236 when it enters the fourth region A4 of the second opposite principal surface 221C of the second light guide plate 221. For this reason, the light emitted from the portion of the light exit surface 40A2 overlapping with the first region A1 and the third region A3 tends to be more easily diffused than the light emitted from the portion overlapping with the second region A2 and the fourth region A4, and the amount of light emitted from the portion of the backlight device 212 overlapping with the first region A1 and the third region A3 tends to be less than the amount of light emitted from the portion overlapping with the second region A2 and the fourth region A4. In this regard, even if the display gradation in the first display section AA1 and the display gradation in the second display section AA2 are the same, the backlight control circuit 53 makes the amount of light emitted per unit time of the fourth LED 38α that supplies light to the portion of the light emitting surface 40A2 that overlaps with the first region A1 and the third region A3 greater than the amount of light emitted per unit time of the fifth LED 38β that supplies light to the portion of the light emitting surface 40A2 that overlaps with the second region A2 and the fourth region A4. This makes it difficult for a difference to occur between the amount of light emitted from the portion of the backlight device 212 that overlaps with the first region A1 and the third region A3 and the amount of light emitted from the portion of the backlight device 212 that overlaps with the second region A2 and the fourth region A4.

[0133] As described above, according to this embodiment, the backlight control circuit 53 is provided to control the driving of the first LED 226, the second LED 220, and the third LED (third light source) 38, and the third LED 38 is arranged in a plane so as to overlap with the light exit surface (fifth main surface) 40A2 of the diffusion plate (optical member) 40A, and the light entrance surface 40A1 of the diffusion plate 40A is configured by the main surface opposite to the light exit surface 40A2, and the light entrance surface 40A1 is arranged opposite to the third LEDs 38. When the backlight control circuit 53 turns on the third LEDs 38, light enters the light entrance surface 40A1 of the diffusion plate 40A, which is opposite to the light exit surface 40A2, and is given an optical effect by the diffusion plate 40A before being emitted from the light exit surface 40A2. By controlling the light emission amount and whether or not to light up each of the multiple third LEDs 38 arranged in a plane so as to overlap with the light exit surface 40A2 by the backlight control circuit 53, so-called local dimming control can be realized.

[0134] The third LEDs 38 include a fourth LED (fourth light source) 38α arranged to overlap the first region A1 and the third region A3, and a fifth LED (fifth light source) 38β arranged to overlap the second region A2 and the fourth region A4, and the backlight control circuit 53 makes the amount of light emitted per unit time of the fourth LED 38α greater than the amount of light emitted per unit time of the fifth LED 38β. When the light emitted from the third LEDs 38 is emitted from the light exit surface 40A2 of the diffusion plate 40A, it passes through the first light guide plate 227 and the second light guide plate 221 and is emitted to the outside. Here, the light emitted from the portion of the light exit surface 40A2 overlapping with the second region A2 and the fourth region A4 may be refracted by the second light reflecting portion 236. On the other hand, the light emitted from the portion of the light emitting surface 40A2 overlapping with the first region A1 and the third region A3 tends to be more easily diffused than the light emitted from the portion of the light emitting surface 40A2 overlapping with the second region A2 and the fourth region A4 because it may be refracted by both the first light reflecting portion 235 and the second light reflecting portion 236. In this regard, the backlight control circuit 53 makes the light emission amount per unit time of the fourth LED 38α that supplies light to the portion of the light emitting surface 40A2 overlapping with the first region A1 and the third region A3 greater than the light emission amount per unit time of the fifth LED 38β that supplies light to the portion of the light emitting surface 40A2 overlapping with the second region A2 and the fourth region A4, so that the backlight device 212 is less likely to have unevenness in the amount of emitted light.

[0135] <Embodiment 4> A fourth embodiment will be described with reference to Fig. 28. In this fourth embodiment, the configuration of the third backlight unit 312U3 is changed from that of the first embodiment. Note that a duplicated description of the structure, operation, and effects similar to those of the first embodiment will be omitted.

[0136] As shown in FIG. 28, the third backlight unit 312U3 according to this embodiment is configured by rotating the third backlight unit 12U3 (see FIG. 2) described in the above-mentioned embodiment 1 by 90° around an axis along the Z-axis direction. Specifically, the third backlight unit 312U3 is configured so that the arrangement direction of the third LED 313 and the third light guide plate 314 coincides with the X-axis direction. The third LED 313 is arranged on the left side of the third light guide plate 314 as shown in FIG. 28. Therefore, the positional relationship between the third LED 313 and the third light guide plate 314 in the X-axis direction is opposite to the positional relationship between the first LED 326 and the first light guide plate 327 in the X-axis direction and the positional relationship between the second LED 320 and the second light guide plate 321 in the X-axis direction. The first light guide plate lenses 332 provided in the third light guide plate 314 extend along the X-axis direction, and a plurality of them are arranged side by side along the Y-axis direction. The second light guide plate lenses 333 extend along the X-axis direction, and a plurality of lenses are arranged side by side along the Y-axis direction. The third light guide plate lenses 334 are arranged side by side at intervals along the X-axis direction.

[0137] As shown in FIG. 28, the first prism sheet 316 constituting the third backlight unit 312U3 has a first prism 316B that has a substantially triangular cross section cut along the X-axis direction and extends linearly along the Y-axis direction. The second prism sheet 317 constituting the third backlight unit 312U3 has a second prism 317B that has a substantially triangular cross section cut along the X-axis direction and extends linearly along the Y-axis direction. The first prism 316B and the second prism 317B can selectively provide a light collecting effect in the X-axis direction to the light from the third light guide plate 314 side. In contrast, the arrangement direction of the first light-shielding portion 318C and the first light-transmitting portion 318D constituting the louver 318 coincides with the X-axis direction. Therefore, it can be said that the light collecting direction by the first prism 316B and the second prism 317B coincides with the direction in which the louver 318 limits the light output angle range. This reduces the amount of light (amount of light loss) absorbed by first light-shielding portion 318C as the light emitted from first prism 316B and second prism 317B passes through first light-transmitting portion 318D of louver 318, thereby improving the light utilization efficiency.

[0138] <Embodiment 5> The fifth embodiment will be described with reference to Fig. 29. The fifth embodiment shows a case where the arrangement of the first backlight unit 412U1 and the second backlight unit 412U2 is changed from that of the first embodiment. Note that a duplicated description of the structure, operation, and effects similar to those of the first embodiment will be omitted.

[0139] As shown in Fig. 29, the first backlight unit 412U1 and the second backlight unit 412U2 according to this embodiment are configured by rotating the first backlight unit 412U1 and the second backlight unit 412U2 (see Fig. 1) described in the above-mentioned embodiment 1 by 180° around an axis along the Z-axis direction. The first LED 426 is disposed on the left side of the first light guide plate 427 as shown in Fig. 29. The second LED 420 is disposed on the left side of the second light guide plate 421 as shown in Fig. 29.

[0140] A passenger car equipped with a liquid crystal display device 410 according to this embodiment has a configuration in which the driver's seat is located on the right side of Fig. 29 and the passenger seat is located on the left side of Fig. 29, that is, it is a right-hand drive car. Accordingly, a display area AA of a liquid crystal panel 411 is divided into a first display portion AA1 located on the right side of Fig. 29 in front of the driver's seat, and a second display portion AA2 located on the left side of Fig. 29 in front of the passenger seat. A first opposite principal surface 427C of a first light guide plate 427 is divided into a first area A1 located on the right side of Fig. 29 and overlapping with the first display portion AA1, and a second area A2 located on the left side of Fig. 29 and overlapping with the second display portion AA2. Similarly, the second opposite principal surface 421C of the second light guide plate 421 is divided into a third region A3 on the right side of FIG. 29 overlapping with the first region A1 (first display portion AA1), and a fourth region A4 on the left side of FIG. 29 overlapping with the second region A2 (second display portion AA2).

[0141] The first light reflecting portion 435 is selectively provided in the first region A1 located on the right side of FIG. 29 on the first opposite main surface 427C, and is selectively not formed in the second region A2 located on the left side of FIG. 29. The light distribution of the light emitted from the first LED 426, propagated through the first light guide plate 427, and then raised by the first light reflecting portion 435 and emitted is laterally reversed from the orientation distribution shown in FIG. 13. The second light reflecting portion 436 is provided across the third region A3 and the fourth region A4 on the second opposite main surface 421C. The light distribution of the light emitted from the second LED 420, propagated through the second light guide plate 421, and then raised by the second light reflecting portion 436 and emitted is laterally reversed from the orientation distribution shown in FIG. 13. Even with this configuration, the same action and effect as those of the above-mentioned embodiment 1 can be obtained.

[0142] <Embodiment 6> A sixth embodiment will be described with reference to Fig. 30 or 31. In this sixth embodiment, a case where the configuration of the first backlight unit 512U1 is changed from that of the first embodiment will be described. Note that a duplicated description of the structure, operation, and effects similar to those of the first embodiment will be omitted.

[0143] As shown in FIG. 30, the first backlight unit 512U1 according to this embodiment includes a second louver (second sheet) 19 in addition to the first LED 526 and the first light guide plate 527. The second louver 19 is disposed on the front side of the first light guide plate 527. That is, the second louver 19 is disposed to be sandwiched between the first light guide plate 527 and the second light guide plate 521 in the Z-axis direction. The second louver 19 has a sheet-like shape with its main surface parallel to each main surface of the first light guide plate 527, etc. Note that the main surface of the second louver 19 is parallel to the X-axis direction and the Y-axis direction, and the normal direction (thickness direction) of the main surface coincides with the Z-axis direction. The second louver 19 has a function of limiting the emission angle range of light in the X-axis direction. The second louver 19 is approximately the same size as the first light guide plate 527 in a plan view, and is disposed so as to overlap at least the entire display area AA in a plan view. The second louver 19 has a second louver light entering principal surface (ninth principal surface) 19A on the back side and a second louver light exiting principal surface (eighth principal surface) 19B on the front side. The second louver light entering principal surface 19A is arranged to face the first light guide plate light exiting principal surface (first principal surface) 527B of the first light guide plate 527 and faces the first light guide plate light exiting principal surface 527B. The second louver light exiting principal surface 19B is arranged to face the second light guide plate opposite principal surface 521C of the second light guide plate 521 and faces the second light guide plate opposite principal surface 521C.

[0144] As shown in FIG. 31, the second louver 19 has a second light-shielding portion 19C that blocks light and a second light-transmitting portion 19D that transmits light. The second light-shielding portion 19C is made of a light-shielding resin material (light-shielding material) that is, for example, black and blocks light. The second light-shielding portion 19C is layered and extends along the Y-axis direction and the Z-axis direction, and a plurality of the second light-transmitting portions 19C are arranged side by side at intervals in the X-axis direction. The second light-transmitting portion 19D is made of a light-transmitting resin material (light-transmitting material) that is almost transparent and transmits light. The second light-transmitting portion 19D is layered and extends along the Y-axis direction and the Z-axis direction, and a plurality of the second light-shielding portions 19C and the second light-transmitting portions 19D are arranged side by side at intervals in the X-axis direction. The plurality of second light-shielding portions 19C and the second light-transmitting portions 19D are arranged side by side alternately and repeatedly in the X-axis direction. Therefore, a second light transmitting portion 19D is interposed between two adjacent second light shielding portions 19C spaced apart in the X-axis direction, and a second light shielding portion 19C is interposed between two adjacent second light transmitting portions 19D spaced apart in the X-axis direction. Light incident on the second louver light-entering main surface 19A of the second louver 19 passes through the second light transmitting portion 19D arranged between two adjacent second light shielding portions 19C in the X-axis direction, and is emitted from the second louver light-exiting main surface 19B. The emission angle in the X-axis direction of the light emitted from the second louver light-exiting main surface 19B is limited by the two adjacent second light shielding portions 19C in the X-axis direction. The emission angle of the light emitted from the second louver light-exiting main surface 19B is not limited by the second louver 19 in the Y-axis direction. The range of the emission angle in the X-axis direction of the light emitted from the second louver light-emitting main surface 19B is defined by two straight lines that diagonally connect the ends in the Z-axis direction of the two second light-shielding portions 19C that sandwich the second light-transmitting portion 19D. The range of the emission angle in the X-axis direction of the light transmitted through the second light-transmitting portion 19D changes according to the ratio of the width W2 and the height H2 of the second light-transmitting portion 19D. The second louver 19 also has a pair of sheet carriers that sandwich and support the multiple second light-shielding portions 19C and the multiple second light-transmitting portions 19D from the front and back sides. The sheet carriers are made of a translucent resin material that is almost transparent and transmits light. The sheet carriers extend over the entire area of ​​the second louver 19 and hold the multiple second light-shielding portions 19C and the multiple second light-transmitting portions 19D collectively.

[0145] Specifically, as shown in FIG. 31, the ratio of the width W2 of the second light transmitting portion 19D divided by the height H2 of the second louver 19 is equal to "tan 45°". That is, the width W2 and the height H2 of the second light transmitting portion 19D are equal, and the cross-sectional shape cut along the Z-axis direction and the X-axis direction is substantially square. In this way, the maximum absolute value of the angle that the light passing through the second light transmitting portion 19D makes with respect to the Z-axis direction is, for example, 45°. The ratio (tan 45°) of the width W2 of the second light transmitting portion 19D divided by the height H2 is larger than the ratio (tan 10°) of the width W1 of the first light transmitting portion 518D of the first louver 518 divided by the height H1. The emission angle range of light that passes through the second light-transmitting portion 19D and exits the second louver light-emitting main surface 19B is ±45° when the Z-axis direction is 0°, which is wider than the emission angle range (±10°) of light that passes through the first light-transmitting portion 518D and exits the first louver light-emitting main surface 518B.

[0146] Here, for example, if the second region A2 of the first opposite principal surface 527C of the first light guide plate 527 is scratched, the light propagating within the first light guide plate 527 may be scattered by the scratch and emitted from a portion of the first light guide plate light output principal surface 527B that overlaps with the second region A2. Even in this case, since the second louver 19 is disposed on the front side of the first light guide plate light output principal surface 527B, the emission angle range of the light emitted from the portion of the first light guide plate light output principal surface 527B that overlaps with the second region A2 can be limited to within the range of ±45°. Therefore, when the first LED 526 and the third LED 13 (see FIG. 2) are turned on and the second LED 520 is turned off, even if the light emitted from the first LED 526 and propagating through the first light guide plate 527 is emitted from a portion of the first light guide plate light output main surface 527B that overlaps with the second region A2 due to a scratch or the like generated in the second region A2 of the first opposite main surface 527C, the light can be largely prevented from being emitted in an angle range exceeding 45° in absolute value (+45° to +90°, −45° to −90°). As a result, when the first LED 526 and the third LED 13 (see FIG. 2) are turned on and the second LED 520 is turned off, the display image of the second display unit AA2 located in front of the passenger seat in the display area AA is less likely to be visible from the driver's seat, improving the display performance in the "partial privacy mode". On the other hand, when the second LED 520 and the third LED 13 (see FIG. 2) are turned on and the first LED 526 is turned off, the light emitted from the second light guide plate 521 does not pass through the second louver 19, and therefore the emission angle range is not limited. In contrast, although the light emitted from the third backlight unit 512U3 passes through the second light transmitting portion 19D of the second louver 19 and is emitted to the outside, the emission angle range limited by the second louver 19 is wider than that of the first louver 518, so that almost no light is absorbed by the second light blocking portion 19C, and a decrease in brightness caused by the second louver 19 is almost avoided.

[0147] As described above, according to this embodiment, the second louver (second sheet) 19 is provided, one of whose main surfaces is the second louver light exiting main surface (eighth main surface) 19B and the other of whose main surfaces is the second louver light entering main surface (ninth main surface) 19A arranged facing the first light guide plate light exiting main surface 527B, and the second louver 19 has at least two second light blocking portions 19C arranged at an interval in the first direction to block light, and a second light transmitting portion 19D arranged between the two second light blocking portions 19C to transmit light. If the second region A2 of the first opposite main surface 527C of the first light guide plate 527 is scratched or the like, the light propagating in the first light guide plate 527 may be emitted from the first light guide plate light exiting main surface 527B due to the scratch or the like. Even in this case, because the second louver 19 is disposed with the second louver light entering principal surface 19A facing the first light guide plate light exiting principal surface 527B, the light emitted from the portion of the first light guide plate light exiting principal surface 527B that overlaps with the second region A2 is partly absorbed by the second light blocking portion 19C in the process of passing through the second light transmitting portion 19D of the second louver 19. In other words, even if the light is scattered by scratches or the like occurring in the second region A2 of the first opposite principal surface 527C, the emission angle range is limited by the second louver 19, so inadvertent emission of light can be suppressed.

[0148] <Other embodiments> The technology disclosed in this specification is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments, for example, are also included in the technical scope.

[0149] (1) The second light guide plate 21-1 may have a configuration shown in Fig. 32. In the second light guide plate 21-1 shown in Fig. 32, the second light reflecting portion 36-1 is selectively provided in the fourth region A4 of the second opposite principal surface 21C-1, and is selectively not formed in the third region A3. In such a configuration, when performing display in the second display mode, the backlight control circuit 53 (see Fig. 12) may perform control so as to light up all of the first LED 26-1, the second LED 20-1, and the third LED 13 (see Fig. 3).

[0150] (2) The specific configuration of the sixth light guide plate lens 24 constituting the second light reflecting portion 36, 236, 436 may be changed as appropriate. For example, the sixth light guide plate inclined surface 24Aα of the sixth light guide plate lens 24α arranged in the fourth region A4 may include a plurality of types having different inclination angles with respect to the X-axis direction. Similarly, the sixth light guide plate inclined surface 24Aβ of the sixth light guide plate lens 24β arranged in the third region A3 may include a plurality of types having different inclination angles with respect to the X-axis direction.

[0151] (3) As a result of changing the configuration of the sixth light guide plate lens 24 as described above in (2), the light distribution of the light emitted from the second LED 20, 120, 220, 320, 420, 520, propagating through the second light guide plate 21, 121, 221, 321, 421, 521, and then being raised and emitted by the second light reflecting portion 36, 236, 436 may be different from the orientation distribution shown in FIG. 13 (asymmetric orientation distribution) and may be, for example, an orientation distribution that is approximately symmetric, and the emission angle range may be different from -80° to +20°.

[0152] (4) In addition to the above (2), the sixth light guide plate inclined surface 24Aα of the sixth light guide plate lens 24α arranged in the fourth region A4 and the sixth light guide plate inclined surface 24Aβ of the sixth light guide plate lens 24β arranged in the third region A3 may have different inclination angles with respect to the X-axis direction. Accordingly, the light distribution of the light emitted from the second LED 20, 120, 220, 320, 420, 520, propagated through the second light guide plate 21, 121, 221, 321, 421, 521, and then raised by the second light reflecting portion 36, 236, 436 and emitted may be different between the third region A3 and the fourth region A4. For example, the light distribution of the light emitted from the fourth region A4 may be as shown in FIG. 13, whereas the light distribution of the light emitted from the third region A3 may be a light distribution that is a mirror image of the light distribution shown in FIG. 13.

[0153] (5) The specific configuration of the ninth light guide plate lens 30 constituting the first light reflecting portion 35, 235, 435 may be changed as appropriate. For example, the ninth light guide plate inclined surface 30A of the ninth light guide plate lens 30 may include a plurality of types having different inclination angles with respect to the X-axis direction.

[0154] (6) As a result of changing the configuration of the ninth light guide plate lens 30 as described in (5) above, the light distribution of the light emitted from the first LED 26, 126, 226, 326, 426, 526, propagating through the first light guide plate 27, 127, 227, 327, 427, 527, and then being raised and emitted by the first light reflecting portion 35, 235, 435 may be different from the orientation distribution shown in FIG. 13 (asymmetric orientation distribution) and may be, for example, an orientation distribution that is approximately symmetric, and the emission angle range may be different from -80° to +20°.

[0155] (7) The first light guide plate light output principal surface 27B, 527B of the first light guide plate 27, 127, 227, 327, 427, 527 may be flat without the seventh light guide plate lens 28, which is a lenticular lens. Similarly, the second light guide plate light output principal surface 21B, 121B of the second light guide plate 21, 121, 221, 321, 421, 521 may be flat without the fourth light guide plate lens 22, which is a lenticular lens. Moreover, the third light guide plate light output principal surface 14B of the third light guide plate 14, 314 may be flat without the first light guide plate lens 32, 332, which is a lenticular lens.

[0156] (8) Instead of the diffusion sheet 12S arranged on the outermost side of the backlight device 12, 212, for example, a third louver may be provided. The third louver is configured by rotating the above-mentioned first louver 18, 118, 218, 318, 518 by 90 degrees around an axis along the Z-axis direction, and is configured by repeatedly arranging light-shielding portions and light-transmitting portions alternately along the Y-axis direction. By arranging the third louver on the outermost side of the backlight device 12, 212, it is possible to limit the emission angle range in the Y-axis direction, thereby preventing reflection on the windshield of a passenger vehicle.

[0157] (9) The area ratio of the first display portion AA1 (first area A1, third area A3) to the second display portion AA2 (second area A2, fourth area A4) can be changed appropriately to a ratio other than 1:1.

[0158] (10) In the configurations described in the first, second, fourth, fifth and sixth embodiments, other types of optical sheets may be used instead of the first prism sheets 16, 316 and the second prism sheets 17, 317 included in the third backlight units 12U3, 312U3 and 512U3. Also, other types of optical sheets may be added to the third backlight units 12U3, 312U3 and 512U3.

[0159] (11) The configuration described in the second embodiment can be appropriately combined with the configuration described in any one of the third, fourth, and fifth embodiments.

[0160] (12) The number, layering order, types, and so forth of the optical members described in the third embodiment can be changed as appropriate.

[0161] (13) Three or more display modes may be set. For example, a third display mode may be set in which the backlight control circuit 53 turns on the third LEDs 13 and 313 and turns off the first LEDs 26, 126, 226, 326, 426, and 526 and the second LEDs 20, 120, 220, 320, 420, and 520.

[0162] (14) The specific values ​​of the contact angle θc1 of the fourth light guide plate lens 22, the contact angle θc2 of the seventh light guide plate lens 28, the apex angle of the second light guide plate lenses 33, 333, the apex angle θ7 of the fifth light guide plate lens 23, and the apex angle θ10 of the eighth light guide plate lens 29, etc., can be changed as appropriate.

[0163] (15) The thickness of the first light guide plate 27, 127, 227, 327, 427, 527 may be decreased as it becomes farther from the first LED 26, 126, 226, 326, 426, 526, and the first opposite principal surface 27C, 227C, 427C, 527C may be inclined. Similarly, the thickness of the second light guide plate 21, 121, 221, 321, 421, 521 may be decreased as it becomes farther from the second LED 20, 120, 220, 320, 420, 520, and the second opposite principal surface 21C, 221C, 421C, 521C may be inclined. Alternatively, the thickness of the third light guide plate 14, 314 may be decreased as it becomes farther from the third LED 13, 313, and the third opposite main surface 14C may be inclined.

[0164] (16) The specific values ​​of the inclination angle and apex angle of each prism slope 16B1, 16B2, 17B1, 17B2 of each prism 16B, 17B, 316B, 317B of each prism sheet 16, 17, 316, 317 can be changed as appropriate. The specific material used for each base material 16A, 17A of each prism sheet 16, 17, 316, 317 can be changed as appropriate. Similarly, the specific material used for each prism 16B, 17B, 316B, 317B can also be changed as appropriate.

[0165] (17) The specific cross-sectional shape of each of the prisms 16B, 17B, 316B, and 317B of each of the prism sheets 16, 17, 316, and 317 may be changed as appropriate. In this case, for example, any of the prism slopes 16B1, 16B2, 17B1, and 17B2 of each of the prisms 16B, 17B, 316B, and 317B may be curved to have a plurality of inclination angles.

[0166] (18) In the first louvers 18, 118, 218, 318, 518, the specific numerical value of the ratio (tan θ) obtained by dividing the width W1 of the first translucent portion 18D, 318D, 518D by the height H1 can be changed appropriately to a value other than tan 10°, for example, tan 12.5°, tan 15°, tan 17.5°, etc.

[0167] (19) Each of the LEDs 13, 20, 26, 120, 126, 220, 226, 313, 320, 326, 420, 426, 520, and 526 may be either a side-emitting type or a top-emitting type. Also, it is possible to use an OLED (Organic Light Emitting Diode) or the like as a light source other than an LED.

[0168] (20) Instead of the first prism sheet 16, 316 and the second prism sheet 17, 317, a prism sheet having prisms provided on the rear main surface (light incident main surface) may be used.

[0169] (21) The present invention can also be applied to liquid crystal display devices 10, 410 used for purposes other than vehicle use.

[0170] (22) In the second louver 19 described in the sixth embodiment, the specific value of the ratio (tan θ) of the width W2 of the second light transmitting portion 19D divided by the height T2 can be changed as appropriate to a value other than tan 45°. In this case, it is preferable that the ratio of the width W2 of the second light transmitting portion 19D divided by the height H2 is larger than the ratio of the width W1 of the first light transmitting portion 18D, 318D, 518D divided by the height H1, but this is not necessarily limited to the case.

[0171] (23) The configuration (second louver 19) described in the sixth embodiment may be appropriately combined with the configurations described in the second to fifth embodiments. [Explanation of symbols]

[0172] 10,410...Liquid crystal display device (display device), 11,411...Liquid crystal panel (display panel), 12,212...Backlight device (illumination device), 13,313...Third LED (third light source), 13α...Fourth LED (fourth light source), 13β...Fifth LED (fifth light source), 14,314...Third light guide plate (optical member), 14A...Third light entrance end surface (light entrance surface), 14B...Third light guide plate light exiting main surface (fifth main surface), 18,118,218,318,518...First louver (first sheet), 18A...First louver light entrance main surface (seventh main surface), 18B, 518B...first louver light exiting main surface (sixth main surface), 18C, 318C...first light blocking portion, 18D, 318D, 518D...first light transmitting portion, 19...second louver (second sheet), 19A...second louver light entering main surface (ninth main surface), 19B...second louver light exiting main surface (eighth main surface), 19C...second light blocking portion, 19D...second light transmitting portion, 20, 120, 220, 320, 420, 520...second LED (second light source), 21, 121, 221, 321, 421, 521...second light guide plate, 21A...second light entering end surface (second end surface), 21B, 121B...second 2 light guide plate light output main surface (third main surface), 21C, 221C, 421C, 521C... second opposite main surface (fourth main surface), 24... sixth light guide plate lens (second lens), 24Aα... sixth light guide plate inclined surface (first inclined surface), 24Aβ... sixth light guide plate inclined surface (second inclined surface), 26, 126, 226, 326, 426, 526... first LED (first light source), 27, 127, 227, 327, 427, 527... first light guide plate, 27A... first light input end surface (first end surface), 27B, 527B... first light guide plate light output main surface (first main surface), 27C, 227C, 427C, 527 C...first opposite principal surface (second principal surface), 30...ninth light guide plate lens (first lens), 30A...ninth light guide plate inclined surface (third inclined surface), 35,235,435...first light reflecting portion, 36,236,436...second light reflecting portion, 38...third LED (third light source), 38α...fourth LED (fourth light source), 38β...fifth LED (fifth light source), 40A...diffusion plate (optical member), 40A1...light incident surface, 40A2...light exit surface (fifth principal surface), 53...backlight control circuit (light source control portion), A1...first region, A2...second region, A3...third region, A4...fourth region

Claims

1. A first light source; a first light guide plate in which at least a part of an outer peripheral end surface is a first end surface facing the first light source and into which light is incident, one main surface is a first main surface from which light is emitted, and the other main surface is a second main surface; A second light source; a second light guide plate in which at least a part of an outer peripheral end surface is a second end surface facing the second light source and into which light is incident, one main surface is a third main surface from which light exits, and the other main surface is a fourth main surface; A third light source; an optical member having a light incident surface facing the third light source and through which light is incident, and a fifth main surface from which light is emitted; a first sheet having one principal surface as a sixth principal surface and the other principal surface as a seventh principal surface arranged facing the fifth principal surface; the first light guide plate and the second light guide plate are disposed on an opposite side to the optical member side with respect to the first sheet, and have main surfaces overlapping each other; the first sheet has at least two first light-shielding portions that are spaced apart from each other in a first direction including a direction from the first light source toward the first light guide plate and that block light, and a first light-transmitting portion that is arranged between the two first light-shielding portions and that transmits light; A first light reflecting portion that reflects light and promotes light emission from the first main surface is provided on the second main surface, a second light reflecting portion that reflects light and promotes light emission from the third main surface is provided on the fourth main surface; When the second main surface is divided into a first region and a second region adjacent to the first region in the first direction, the first light reflecting portion is selectively provided in the first region on the second main surface, a light emitting element configured to emit light from the first region and the second region and having a width that is larger than the width of the first region and a width that is larger than the width of the second region;

2. The lighting device according to claim 1 , wherein the second light reflecting portion is provided across the third region and the fourth region on the fourth main surface.

3. the first light reflecting portion includes a plurality of first lenses arranged side by side along the first direction on the second main surface, the second light reflecting portion includes a plurality of second lenses arranged side by side along the first direction on the fourth main surface, 3. The lighting device according to claim 2, wherein among the plurality of second lenses, at least the second lens arranged in the fourth region has a first inclined surface that rises from the side opposite the second light source in the first direction toward the second light source.

4. 4. The lighting device according to claim 3, wherein among the plurality of second lenses, the second lens arranged in the third region has a second inclined surface that rises from the side opposite the second light source in the first direction toward the second light source.

5. The lighting device according to claim 4 , wherein the first inclined surface and the second inclined surface have the same inclination angle with respect to the first direction.

6. a positional relationship of the first light source with respect to the first light guide plate in the first direction is the same as a positional relationship of the second light source with respect to the second light guide plate in the first direction, 6 . The lighting device according to claim 3 , wherein the first lenses each have a third inclined surface that is inclined upward from a side opposite to the first light source in the first direction toward the first light source.

7. a light source control unit that controls driving of the first light source, the second light source, and the third light source, 6. The lighting device according to claim 2, wherein the light source control unit switches between a first mode in which the first light source and the third light source are turned on and the second light source is turned off, and a second mode in which the second light source and the third light source are turned on and the first light source is turned off, based on an input of a switching signal.

8. The lighting device according to claim 2 , wherein the second light guide plate is disposed so as to sandwich the first light guide plate between the second light guide plate and the first sheet.

9. The lighting device according to claim 2 , wherein the first light guide plate is disposed so as to sandwich the second light guide plate between the first sheet and the first light guide plate.

10. 6. The lighting device according to claim 1, wherein the optical member comprises a third light guide plate, the light incident surface being formed by at least a portion of an outer peripheral end surface, and the light incident surface is arranged opposite the third light source.

11. a light source control unit that controls driving of the first light source, the second light source, and the third light source, the light incident surface is a portion of the outer peripheral end surface of the third light guide plate extending along the first direction, The third light source includes a plurality of third light sources arranged in the first direction, the third light sources include a fourth light source arranged to face a portion of the third light guide plate overlapping with the first region and the third region, and a fifth light source arranged to face a portion of the third light guide plate overlapping with the second region and the fourth region, The illumination device according to claim 10 , wherein the light source control unit controls the amount of light emitted per unit time of the fourth light source to be greater than the amount of light emitted per unit time of the fifth light source.

12. a light source control unit that controls driving of the first light source, the second light source, and the third light source, The third light source is arranged in a plane so as to overlap with the fifth main surface, The lighting device according to claim 1 , wherein the optical member has a light incident surface that is configured by a main surface opposite to the fifth main surface, and the light incident surface is arranged opposite the third light sources.

13. the third light sources include a fourth light source arranged to overlap the first region and the third region, and a fifth light source arranged to overlap the second region and the fourth region, The illumination device according to claim 12 , wherein the light source control unit controls the amount of light emitted per unit time of the fourth light source to be greater than the amount of light emitted per unit time of the fifth light source.

14. a second sheet having one principal surface serving as an eighth principal surface and the other principal surface serving as a ninth principal surface facing the first principal surface; 6. The lighting device according to claim 1, wherein the second sheet has at least two second light-shielding portions arranged at an interval in the first direction to block light, and a second light-transmitting portion arranged between the two second light-shielding portions to transmit light.

15. The lighting device according to any one of claims 1 to 5, a display panel that performs display using light from the illumination device.

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