Illumination device and display device

Abstract

An exit angle range is limited for a portion of the exit light. The lighting device (12) comprises: a first light source (26); a first light guide plate (27) having a second main surface (27C); a second light source (20); a second light guide plate (21) having a fourth main surface (21C); a third light source (13); the main surfaces of the optical member (14), the first sheet (18), the first light guide plate (27), and the second light guide plate (21) overlap with each other and are disposed on the opposite side of the optical member (14) side with respect to the first sheet (18), the first sheet (18) has two first light shielding portions (18C) and a first light transmitting portion (18D), a second main surface (27C) is provided with a first light reflecting portion (35), and a fourth main surface (21C) is provided with a second light reflecting portion (36). The first light reflecting section (35) is selectively provided in the first region (A1) on the second main surface (27C), and the second light reflecting section (36) is provided in at least the fourth region (A4) on the fourth main surface (21C).

Description

Technical Field

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

[0002] Conventionally, as an example of a lighting device, there is known a lighting device described in the following patent document 1. The lighting device described in patent document 1 operates in at least two operation modes, namely, a free view mode and a restricted view mode. The lighting device includes a backlight system. A light guide plate is arranged in front of the backlight system, and a light source is arranged along the side of the light guide plate. The light guide plate has diffusion particles composed of a polymer dispersed in a resin matrix 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 restricted view mode, the light source is turned on and the backlight system is turned off. Prior art literature Patent Literature

[0003] Patent Document 1: U.S. Patent Application Publication No. 2017 / 0069236 Summary of the invention Problem that the invention aims to solve

[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 restricted view mode, and the emission angle range of all emitted light is not limited in the free view mode. However, in patent document 1, there is the following problem: it is impossible to cope with the situation where the emission angle range is required to be limited for a part of the emitted light, and the emission angle range is not limited for the remaining part of the emitted light.

[0005] The technology described in this specification is a technology completed based on the above situation, and its purpose is to limit the emission angle range of a part of the emitted light. Solutions to the problem

[0006] (1) The lighting device involved in the technology described in this specification includes: a first light source; a first light guide plate, at least a portion of its outer peripheral end surface is set as a first end surface that is opposite to the first light source and for light to be incident, and one principal surface of the first light guide plate is set as a first principal surface from which light is emitted, and the other principal surface is set as a second principal surface; a second light source; a second light guide plate, at least a portion of its outer peripheral end surface is set as a second end surface that is opposite to the second light source and for light to be incident, and one principal surface of the second light guide plate is set as a third principal surface from which light is emitted, and the other principal surface is set as a fourth principal surface; a third light source; an optical component having a light incident surface and a fifth principal surface, the light incident surface being opposite to the third light source and for light to be incident, and the fifth principal surface for light to be emitted; and a first sheet material, one principal surface of which is set as a sixth principal surface and the other principal surface of which is set as a seventh principal surface arranged toward the fifth principal surface, the principal surfaces of the first light guide plate and the second light guide plate overlap with each other, and the optical component is arranged on the side relative to the first sheet material. On the opposite side of the first sheet, the first sheet at least has: two first shading portions, the two first shading portions are arranged at intervals in a first direction including a direction from the first light source toward the first light guide plate, and block light; and a first light-transmitting portion, which is arranged between the two first shading portions and transmits light, a first light reflecting portion is provided on the second main surface, the first light reflecting portion reflects light to promote the light output from the first main surface, and a second light reflecting portion is provided on the fourth main surface, the second light reflecting portion reflects light to promote the light output from the third main surface, when the second main surface is divided into a first area and a second area adjacent to the first area in the first direction, the first light reflecting portion is selectively arranged in the first area on the second main surface, and when the fourth main surface is divided into a third area overlapping with the first area and a fourth area overlapping with the second area, the second light reflecting portion is at least arranged in the fourth area on the fourth main surface.

[0007] (2) In addition, the lighting device described above may be configured as described in (1) above, wherein the second light reflecting portion is provided on the fourth main surface over the third region and the fourth region.

[0008] (3) In addition, the above-mentioned lighting device can also be based on the above-mentioned (2), wherein the first light reflecting part is composed of a plurality of first lenses, and the plurality of first lenses are arranged along the first direction on the second principal surface; the second light reflecting part is composed of a plurality of second lenses, and the plurality of second lenses are arranged along the first direction on the fourth principal surface; the second lenses arranged in at least the fourth area among the plurality of second lenses have an inclined first slope, and the inclination of the first slope is to rise from the side opposite to the second light source toward the second light source side in the first direction.

[0009] (4) In addition, the above-mentioned lighting device can also be based on the above-mentioned (3), wherein the second lens arranged in the third area among the plurality of second lenses has an inclined second slope, and the inclination of the second slope is to rise from the side opposite to the second light source toward the second light source side in the first direction.

[0010] (5) In addition, the lighting device described above may be configured as described in (4) above, wherein the first inclined surface and the second inclined surface have the same inclination angle relative to the first direction.

[0011] (6) In addition, the above-mentioned lighting device can also be based on any one of the above-mentioned (3) to (5), wherein the position relationship of the first light source relative to the first light guide plate in the first direction is the same as the position relationship of the second light source relative to the second light guide plate in the first direction, and the plurality of first lenses have an inclined third slope, and the inclination of the third slope is to rise from the side opposite to the first light source toward the first light source side in the first direction.

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

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

[0015] (10) In addition, the above-mentioned lighting device can also be based on any one of the above-mentioned (1) to (9), wherein in the optical component, the light incident surface is composed of at least a portion of the outer peripheral end surface, and the light incident surface is composed of a third light guide plate arranged opposite to the third light source.

[0016] (11) In addition, the above-mentioned lighting device can also be based on the above-mentioned (10), and the lighting device includes a light source control unit, and the light source control unit controls the driving of the first light source, the second light source and the third light source, the light incident surface is composed of a portion of the outer peripheral end surface of the third light guide plate extending along the first direction, and a plurality of third light sources are arranged along the first direction, and the plurality of third light sources include: a fourth light source, which is arranged opposite to the portion of the third light guide plate overlapping the first area and the third area; and a fifth light source, which is arranged opposite to the portion of the third light guide plate overlapping the second area and the fourth area, and the light source control unit makes the light emission per unit time of the fourth light source greater than the light emission per unit time of the fifth light source.

[0017] (12) In addition, the above-mentioned lighting device can also be based on any one of the above-mentioned (1) to (9), and the lighting device includes a light source control unit, and the light source control unit controls the driving of the first light source, the second light source and the third light source, and the third light source is arranged in a plane in a manner overlapping with the fifth main surface. In the optical component, the light incident surface is composed of a main surface on the side opposite to the fifth main surface, and the light incident surface is arranged opposite to the plurality of third light sources.

[0018] (13) In addition, the above-mentioned lighting device can also be based on the above-mentioned (12), wherein the multiple third light sources include: a fourth light source, which is arranged to overlap with the first area and the third area; and a fifth light source, which is arranged to overlap with the second area and the fourth area, and the light source control unit makes the light emission of the fourth light source per unit time greater than the light emission of the fifth light source per unit time.

[0019] (14) In addition, the above-mentioned lighting device can also be based on any one of the above-mentioned (1) to (13), and the lighting device has a second sheet, one principal surface of the second sheet is set as the eighth principal surface, and the other principal surface is set as the ninth principal surface arranged toward the first principal surface, and the second sheet has at least: two second light-shielding portions, the two second light-shielding portions are arranged at intervals in the first direction and block light; and a second light-transmitting portion, which is arranged between the two second light-shielding portions and transmits light.

[0020] (15) A display device according to the technology described in this specification includes: a lighting device described in any one of (1) to (14) above; and a display panel that performs display using light from the lighting device. Effects of the Invention

[0021] According to the technology described in this specification, it is possible to limit the emission angle range of a part of the emitted light. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a side cross-sectional view of the liquid crystal display device according to Embodiment 1. Figure 2 In the liquid crystal display device according to Embodiment 1 Figure 1 Sectional view along line ii-ii. Figure 3 It is a plan view of a backlight device included in the liquid crystal display device according to Embodiment 1. Figure 4 The backlight device according to the first embodiment Figure 2 Section views with the same cutting position. Figure 5 The backlight device according to the first embodiment Figure 1 Section views with the same cutting position. Figure 6 This is a perspective view of a third light guide plate constituting the backlight device according to Embodiment 1, as viewed from the third opposite principal surface side. Figure 7 This is a bottom view showing the structure of the third opposite main surface of the third light guide plate according to the first embodiment. Figure 8 It is a side cross-sectional view of a second light guide plate constituting the backlight device according to the first embodiment. Fig. 9 This is a bottom view showing the structure of the second opposite main surface of the second light guide plate according to the first embodiment. Fig.10 In the liquid crystal display device according to Embodiment 1 Figure 1 xx line cross-sectional view. Fig.11 The backlight device according to the first embodiment Fig.10 Section views with the same cutting position. Fig.12 This is a block diagram showing the electrical configuration of the liquid crystal display device according to Embodiment 1. Fig.13 It is a graph showing the experimental results of the demonstration experiment 1 involved in the embodiment 1, that is, the light distribution in the second display mode or the light distribution of the light emitted from the portion overlapping the first area and the third area in the backlight device in the first display mode. Fig.14 1 is a graph showing the experimental results of the demonstration experiment 1 according to the first embodiment, that is, the light distribution of the light emitted from the portion overlapping the second area and the fourth area in the backlight device in the first display mode. Fig.15 These are diagrams for explaining the light shielding range and the visual recognition range of the first display unit and the second display unit provided in the liquid crystal display device of the passenger car according to the first embodiment. Fig.16 This is a diagram related to brightness distribution, which is an experimental result obtained when the brightness of light emitted from the backlight device at an angle of 0° in the second display mode was measured in the demonstration experiment 2 according to the first embodiment. Fig.17 This is a graph related to brightness distribution, which is an experimental result obtained when the brightness of light emitted from the backlight device at an angle of 0° in the second display mode was measured in the demonstration experiment 2 according to the first embodiment. Fig.18 This is a diagram related to brightness distribution, which is an experimental result obtained when the brightness of light emitted from the backlight device at an angle of −45° in the second display mode was measured in the demonstration experiment 2 according to the first embodiment. Fig.19 This is a graph related to brightness distribution, which is an experimental result obtained when the brightness of light emitted from the backlight device at an angle of −45° in the second display mode was measured in the demonstration experiment 2 according to the first embodiment. Fig. 20 This is a diagram related to brightness distribution, which is an experimental result obtained when the brightness of light emitted from the backlight device at an angle of 0° in the first display mode was measured in the demonstration experiment 2 according to the first embodiment. Fig.21 This is a graph related to brightness distribution, which is an experimental result obtained when the brightness of light emitted from the backlight device at an angle of 0° in the first display mode was measured in the demonstration experiment 2 according to the first embodiment. Fig. 22 This is a diagram related to brightness distribution, which is an experimental result obtained when the brightness 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. Fig.23 This is a graph related to brightness distribution, which is an experimental result obtained when the brightness 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. Fig.24 In the liquid crystal display device according to Embodiment 2 Figure 1 Section views with the same cutting position. Fig.25 The backlight device according to the second embodiment Figure 1 Section views with the same cutting position. Fig.26 In the liquid crystal display device according to Embodiment 3 Figure 1 Section views with the same cutting position. Fig. 27 This is a plan view showing an LED substrate constituting the backlight device according to the third embodiment. Fig.28 In the liquid crystal display device according to Embodiment 4 Figure 1 Section views with the same cutting position. Fig.29 In the liquid crystal display device according to Embodiment 5 Figure 1 Section views with the same cutting position. Fig.30 This is a side sectional view of a liquid crystal display device according to Embodiment 6. Fig.31 is a backlight device according to Embodiment 6. Fig.30 Section views with the same cutting position. Fig.32 In a liquid crystal display device according to another embodiment Figure 1 Section views with the same cutting position. DETAILED DESCRIPTION

[0023] <Implementation Method 1> according to Figures 1 to 23 Embodiment 1 is described. In this embodiment, a liquid crystal display device (display device) 10 is exemplified. In some drawings, the X-axis, Y-axis, and Z-axis are shown, and the directions of the axes are drawn in the directions shown in the drawings. In addition, the up and down directions are shown in FIG. Figure 1 , Figure 2 , Figure 4 , Figure 5 , Figure 8 , Fig.10 as well as Fig.11 As a reference, the upper side of the figure is set as the front side, and the lower side of the figure is set as the back side.

[0024] In this embodiment, if Figure 1 As shown, an example of a vehicle-mounted liquid crystal display device 10 is shown. The vehicle-mounted liquid crystal display device 10 is mounted on, for example, a car navigation system that displays a map as an image, a multi-function display that displays the operating status of equipment such as an air conditioner in addition to a map as an image, an instrument panel that displays instruments, warnings, etc. as an image, an information system that displays television images, audio information, etc. in addition to a map as an image, and is generally in a horizontally long shape. The liquid crystal display device 10 involved in this embodiment has a length close to the width of the vehicle in the vehicle interior from the front of the co-pilot seat to the front of the driver's seat. In addition, the passenger car equipped with the liquid crystal display device 10 involved in this embodiment is a vehicle with a driver's seat located in the front. Figure 1 The left side of the front passenger seat is Figure 1 In addition, in the present embodiment, the liquid crystal display device 10 is arranged in a posture where the X-axis direction is substantially consistent with the horizontal direction and the Y-axis direction is parallel to the vertical direction.

[0025] The liquid crystal display device 10 as a whole is in the shape of a horizontally long strip. Figures 1 to 3 As shown in the figure, its short side direction is consistent with the Y-axis direction, its long side direction is consistent with the X-axis direction, and its thickness direction is consistent with the Z-axis direction. Figure 1 and Figure 2 As shown, the liquid crystal display device 10 includes a liquid crystal panel (display panel) 11 for displaying images and a backlight device (illumination device) 12 that is arranged on the back side of the liquid crystal panel 11 and irradiates light for display toward the liquid crystal panel 11. First, the structure of the liquid crystal panel 11 is described. The liquid crystal panel 11 is in the shape of a plate whose main surface is parallel to the X-axis direction and the Y-axis direction, and the normal direction (thickness direction) of the main surface is consistent with the Z-axis direction. The central side portion of the main surface of the liquid crystal panel 11 is set as a display area AA capable of displaying images, and the frame-shaped peripheral end side portion surrounding the display area AA is set as a non-display area NAA. As shown Figure 1 As shown, the display area AA is divided into two parts located on one side ( Figure 1 The first display portion AA1 on the left side of the X-axis direction and the other side ( Figure 1 The first display unit AA1 is located in front of the driver's seat in the vehicle. The second display unit AA2 is located in front of the passenger seat in the vehicle. The area ratio of the first display unit AA1 and the second display unit AA2 is, for example, 1:1.

[0026] The liquid crystal panel 11 is in the shape of a horizontally long strip as a whole, similarly to the liquid crystal display device 10, and has a pair of substrates and a liquid crystal layer sealed between the pair of substrates. The substrate arranged on the surface side of the pair of substrates constituting the liquid crystal panel 11 is a CF substrate (opposing substrate), and the substrate arranged on the back side is an array substrate (TFT substrate). Color filters such as R (red), G (green), and B (blue), a shading portion (black matrix) separating adjacent color filters, etc. are provided on the CF substrate. The array substrate (TFT substrate) is provided with at least mutually orthogonal gate wiring and source wiring, a switching element (such as TFT) connected to the gate wiring and the source wiring, and a pixel electrode connected to the switching element to form a pixel. In addition, an alignment film is provided on each inner surface of the array substrate and the CF substrate constituting the liquid crystal panel 11. In addition, a polarizing plate is installed on each outer surface of the array substrate and the CF substrate constituting the liquid crystal panel 11.

[0027] As described above, the vehicle-mounted liquid crystal display device 10 according to the present embodiment has a length close to the width of the vehicle, and accordingly, the display area AA of the liquid crystal panel 11 is configured to include a first display unit AA1 located in front of the driver's seat and a second display unit AA2 located in front of the front passenger seat. Therefore, for example, 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 can be visually recognized from the front passenger seat while the passenger car is traveling, and on the other hand, the display image of the first display unit AA1 can be visually recognized from the driver's seat, and the display image of the second display unit AA2 cannot be visually recognized. On the other hand, for example, when the passenger car 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 can be visually recognized from both the front passenger seat and the driver's seat.

[0028] In order to meet such a requirement, the backlight device 12 according to the present embodiment is Figure 1 as well as Figure 2 As shown, there are a diffusion sheet 12S, a second backlight device 12U2 arranged on the back side of the diffusion sheet 12S, a first backlight device 12U1 arranged on the back side of the second backlight device 12U2, and a third backlight device 12U3 arranged on the back side of the first backlight device 12U1. The diffusion sheet 12S is located at the position closest to the light emitting side (the side close to the liquid crystal panel 11) in the backlight device 12, and diffuses the light incident from the back side so that it is emitted toward the liquid crystal panel 11. In the present embodiment, the first backlight device 12U1, the second backlight device 12U2, and the third backlight device 12U3 are all configured as so-called edge-light types. In addition, the backlight device 12 is in the shape of a horizontally long strip as a whole, similar to the liquid crystal display device 10.

[0029] First, the structure of the third backlight device 12U3 is described. Figure 1 and Figure 2 As shown, the third backlight device 12U3 comprises at least: a third LED (third light source) 13; a third light guide plate (optical component) 14, which guides the light from the third LED 13; a reflective sheet 15, which is arranged on the back side of the third light guide plate 14 (the opposite side of the light emitting side); a first prism sheet 16, which is arranged on the surface side (light emitting side) of the third light guide plate 14; a second prism sheet 17, which is arranged on the surface side of the first prism sheet 16; and a first grid (first sheet) 18, which is arranged on the surface side of the second prism sheet 17.

[0030] like Figure 2 As shown, the third LED 13 is substantially block-shaped, and one of the pairs of faces along the X-axis direction and the Z-axis direction becomes the third light-emitting face 13A for emitting light. Figure 3As shown, a plurality of third LEDs 13 are arranged at intervals along the X-axis direction (the first direction described later). The third LED 13 is mounted on an LED substrate. The third LED 13 is configured such that an LED chip is sealed using a sealing material on a substrate portion mounted on the LED substrate. The LED chip provided by the third LED 13 emits, for example, monochromatic blue light. Phosphors are dispersed in the sealing material provided by the third LED 13. The phosphors contained in the sealing material include yellow phosphors, green phosphors, red phosphors, and the like. The third LED 13 having such an LED chip and a sealing material emits white light as a whole.

[0031] The third light guide plate 14 is made of a synthetic resin material (such as acrylic resin such as PMMA) having a refractive index sufficiently higher than that of air and being substantially transparent. Figure 1 as well as Figure 2 As shown, the main surface of the third light guide plate 14 is formed into a plate shape parallel to the main surface of the liquid crystal panel 11. In addition, 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 is consistent with the Z-axis direction. The third light guide plate 14 is configured to overlap at least the entire area of ​​the display area AA when viewed from above. The third light guide plate 14 is arranged along the Y-axis direction relative to the third LED 13, and is arranged along the Z-axis direction relative to the liquid crystal panel 11 and each prism sheet 16, 17. Figure 2 and Figure 3 As shown, the third light guide plate 14 is arranged on one side of the Y-axis direction relative to the third LED 13 ( Figure 3 The third light guide plate 14 has an outer peripheral end surface, and one end surface (portion) extending along the X-axis direction (first direction) is set as a third light incident end surface (light incident surface) 14A opposite to 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 third light incident end surface 14A is incident with light emitted from the third light emitting surface 13A. In this way, in the third light guide plate 14, the third LED 13 is arranged only on one side in the Y-axis direction. Therefore, the third backlight source unit 12U3 is a single-side incident edge light type.

[0032] like Figure 2 As shown, the main surface of the pair of main surfaces of the third light guide plate 14, which is opposite to the first prism sheet 16, becomes the third light guide plate light emitting main surface (fifth main surface) from which the light guided inside is emitted. 14B. The main surface on the back side opposite to the reflective sheet 15 among the pair of main surfaces of the third light guide plate 14 becomes the third opposite main surface (second main surface) 14C located on the side opposite to the light emitting main surface 14B of the third light guide plate. In addition, the third light guide plate 14 has the function of introducing the light emitted from the third LED 13 toward the third light guide plate 14 from the third light incident end surface 14A and emitting the light upward in the Z-axis direction toward the surface side (light emitting side) after the light propagates inside. The detailed structure of the third light guide plate 14 will be described later. In addition, the normal direction of the third light incident end surface 14A is consistent with the Y-axis direction (the arrangement direction of the third LED 13 and the third light guide plate 14).

[0033] like Figure 1 and Figure 2 As shown, the reflective sheet 15 is arranged in such a manner that its main surface is parallel to the main surfaces of the liquid crystal panel 11 and the third light guide plate 14 and covers the third opposite main surface 14C of the third light guide plate 14. The reflective sheet 15 has excellent light reflectivity and can efficiently direct the light leaking from the third opposite main surface 14C of the third light guide plate 14 toward the surface side, that is, the light emitting main surface 14B of the third light guide plate. The reflective sheet 15 has an outer shape that is one size larger than the third light guide plate 14 and is arranged to overlap with the third opposite main surface 14C in substantially the entire area.

[0034] like Figure 1 and Figure 2 As shown, the first prism sheet 16 and the second prism sheet 17 are formed in a sheet shape, and their respective main surfaces are parallel to the main surfaces of the liquid crystal panel 11 and the third light guide plate 14. In addition, the main surfaces of the first prism sheet 16 and the second prism sheet 17 are parallel to the X-axis direction and the Y-axis direction, and the normal direction (thickness direction) of the main surface is consistent with the Z-axis direction. The first prism sheet 16 and the second prism sheet 17 are stacked on the surface side of the third light guide plate 14, and have the function of giving a predetermined optical effect to the light emitted from the third light guide plate light emitting main surface 14B of the third light guide plate 14 so that it can be emitted. The first prism sheet 16 and the second prism sheet 17 are arranged to overlap at least the entire area of ​​the display area AA when viewed from above.

[0035] like Figure 2As shown, the first prism sheet 16 has a first substrate 16A and a first prism 16B. The first substrate 16A is in sheet form, and the first prism 16B is arranged on the main surface (light emitting main surface) of the surface side (light emitting side) of the first substrate 16A. The first substrate 16A is made of a substantially transparent synthetic resin, specifically, a crystalline transparent resin material such as PET (polyethylene terephthalate). During the manufacture, the first substrate 16A is formed into a sheet by stretching the crystalline transparent resin material as the raw material by a biaxial stretching process, which is preferred from the perspective of achieving a reduction in manufacturing costs. The first prism 16B is made of a substantially transparent ultraviolet curing resin material, which is a type of photocurable resin material. When manufacturing the first prism sheet 16, for example, an uncured ultraviolet curable resin material is filled into a molding mold, and the first substrate 16A is attached to the open end of the mold, so that the uncured ultraviolet curable resin material is arranged in contact with the main surface on the surface side. If ultraviolet rays are irradiated to the ultraviolet curable resin material through the first substrate 16A in this state, the ultraviolet curable resin material is cured, and the first prism 16B is integrated with the first substrate 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 set in the range of 1.49 to 1.52, and most preferably set to 1.49.

[0036] like Figure 4 As shown, the first prism 16B is arranged in a manner that protrudes from the main surface of the first substrate 16A along the Z-axis direction toward the surface side (the opposite side of the third light guide plate 14 side). The cross-sectional shape of the first prism 16B cut along the Y-axis direction (the second direction orthogonal to the first direction) is formed into a roughly triangular shape (roughly mountain-shaped) and extends straightly along the X-axis direction, and a plurality of first prisms 16B are arranged continuously and substantially without intervals along the Y-axis direction in the main surface of the first substrate 16A. The first prism 16B has a pair of inclined surfaces 16B1 and 16B2. Among the pair of inclined surfaces 16B1 and 16B2 of the first prism 16B, the inclined surface located on the third LED 13 side in the Y-axis direction is set as the first prism inclined surface 16B1, and the inclined surface on the opposite side is set as the second prism inclined surface 16B2. The first prism inclined surface 16B1 has a protruding portion extending from the third LED 13 side ( Figure 4 ) to the opposite side ( Figure 4 The light incident on the first prism 16B, which mainly travels in the direction close to the third LED 13 in the Y-axis direction, is refracted by the first prism inclined surface 16B1. The second prism inclined surface 16B2 has a first prism sheet 16 on the opposite side from the third LED 13 in the Y-axis direction ( Figure 4The right side of the LED 13 is toward the third LED 13 ( Figure 4 The light incident on the first prism 16B that mainly travels in the direction away from the third LED 13 in the Y-axis direction is refracted by the second prism inclined surface 16B2. Most of the light refracted by the pair of inclined surfaces 16B1 and 16B2 in the first prism 16B is selectively focused upward in the Y-axis direction.

[0037] Moreover, if Figure 4 As shown, in the first prism 16B, when the inclination angle θ1 of the first prism bevel 16B1 relative to the Y-axis direction is compared with the inclination angle θ2 of the second prism bevel 16B2 relative to the Y-axis direction, the former is larger than the latter. That is to say, the first prism 16B is an unequal-sided triangle with an asymmetric cross-sectional shape. Specifically, the inclination angle θ1 of the first prism bevel 16B1 relative to the Y-axis direction is preferably in the range of 50° to 60°, with 55° being the most preferred. In contrast, the inclination angle θ2 of the second prism bevel 16B2 relative to the Y-axis direction is preferably in the range of 35° to 50°, with 55° being the most preferred. 45°. In addition, in the first prism 16B, the angle θ3 formed by a pair of inclined surfaces 16B1 and 16B2 is preferably set in the range of 70° to 95°, and is most preferably set to 80°. In addition, for the multiple first prisms 16B arranged along the Y-axis direction, their height dimensions, width dimensions, inclination angles of each inclined surface 16B1 and 16B2 relative to the Y-axis direction, etc. are all approximately the same, and the arrangement intervals between adjacent first prisms 16B are also approximately fixed and arranged at equal intervals.

[0038] like Figure 2 As shown, the second prism sheet 17 has a second substrate 17A and a second prism 17B, the second substrate 17A is in sheet form, and the second prism 17B is arranged on the main surface (light emitting main surface) of the surface side (light emitting side) of the second substrate 17A. The second substrate 17A is made of a substantially transparent synthetic resin, specifically, a crystalline transparent resin material such as PET, which is the same as the first substrate 16A. The second prism 17B is made of a substantially transparent ultraviolet curing 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 curing resin material constituting the second prism 17B is an acrylic resin such as PMMA, and its refractive index is higher than the refractive index of the material of the first prism 16B, for example, set to about 1.61.

[0039] like Figure 4As shown, the second prism 17B is arranged in a manner that protrudes from the main surface of the second substrate 17A along the Z-axis direction toward the surface side (the opposite side of the first prism sheet 16). The cross-sectional shape of the second prism 17B cut along the Y-axis direction is formed into a roughly triangular shape (roughly mountain-shaped) and extends straightly along the X-axis direction, and a plurality of second prisms 17B are arranged continuously and substantially without intervals along the Y-axis direction in the main surface of the second substrate 17A. The second prism 17B has a pair of inclined surfaces 17B1 and 17B2. Among the pair of inclined surfaces 17B1 and 17B2 of the second prism 17B, the inclined surface located on the third LED 13 side in the Y-axis direction is set as the third prism inclined surface (fifth inclined surface) 17B1, and the inclined surface on the opposite side is set as the fourth prism inclined surface (sixth inclined surface) 17B2. The third prism inclined surface 17B1 has a shape that protrudes from the third LED 13 side ( Figure 4 ) to the opposite side ( Figure 4 The light incident on the second prism 17B, which mainly travels in the direction close to the third LED 13 in the Y-axis direction, is refracted by the third prism inclined surface 17B1. The fourth prism inclined surface 17B2 has a side opposite to the third LED 13 side in the Y-axis direction of the second prism sheet 17 ( Figure 4 The right side of the LED 13 is toward the third LED 13 ( Figure 4 The light incident on the second prism 17B that mainly travels in the direction away from the third LED 13 in the Y-axis direction is refracted by the fourth prism inclined surface 17B2. Most of the light refracted by the pair of inclined surfaces 17B1 and 17B2 in the second prism 17B is selectively focused upward in the Y-axis direction.

[0040] Moreover, if Figure 4As shown, in the second prism 17B, the inclination angle θ4 formed by the third prism inclined surface 17B1 relative to the Y-axis direction is set to be the same as the inclination angle θ5 formed by the fourth prism inclined surface 17B2 relative to the Y-axis direction. In other words, the second prism 17B is an isosceles triangle with a symmetrical cross-sectional shape. On this basis, the inclination angles θ4 and θ5 of the third prism inclined surface 17B1 and the fourth prism inclined surface 17B2 relative to the Y-axis direction are smaller than the inclination angle θ1 of the first prism inclined surface 16B1 relative to the Y-axis direction. Specifically, the inclination angles θ4 and θ5 of the third prism inclined surface 17B1 and the fourth prism inclined surface 17B2 relative to the Y-axis direction are preferably in the range of 40° to 50°, and 45° is most preferred. In contrast, the angle θ6 formed by a pair of inclined surfaces 17B1 and 17B2 of the second prism 17B is preferably set in the range of 80° to 100°, and 90°, i.e., a right angle, is most preferred. In addition, for the plurality of second prisms 17B arranged along the Y-axis direction, the height dimension, width dimension, inclination angle of each inclined surface 17B1 and 17B2 relative to the Y-axis direction, etc. are all substantially the same, and the arrangement intervals between adjacent second prisms 17B are also substantially fixed and arranged at equal intervals. In addition, the height dimension and arrangement interval of the second prisms 17B are different from the height dimension and arrangement interval of the first prisms 16B, but this is preferred from the perspective of suppressing the generation of interference fringes called moiré.

[0041] According to the first prism sheet 16 and the second prism sheet 17 constructed as described above, the following functions and effects can be obtained. That is, for the light emitted from the third light guide plate light emitting main surface 14B of the third light guide plate 14 and incident on the first prism sheet 16, most of it is irradiated to the second prism bevel 16B2 of the first prism 16B and refracted, and is emitted while rising, or is directed to the first prism bevel 16B1. Here, since the inclination angle θ1 formed by the first prism bevel 16B1 with respect to the Y-axis direction in the first prism 16B is greater than the inclination angle θ2 formed by the second prism bevel 16B2 with respect to the Y-axis direction, the light incident on the first prism sheet 16 is less likely to be irradiated to the first prism bevel 16B1 than in the case where the same angle or the size of the angle is set to an opposite relationship. If the incident light of the first prism 16 is irradiated to the first prism bevel 16B1 of the first prism 16B, it will not rise when emitted from the first prism 16B, but tends to be easily emitted as side lobe light (stray light). Therefore, if the incident light of the first prism sheet 16 is less likely to directly hit the first prism slope 16B1 of the first prism 16B, the generation of side lobe light can be suppressed, and as a result, the light utilization efficiency is improved.

[0042] Most of the light emitted from the first prism sheet 16 and incident on the second prism sheet 17 is refracted by the fourth prism inclined surface 17B2 of the second prism 17B, and is emitted while rising, or is directed toward the third prism inclined surface 17B1. Here, since the inclination angle θ5 formed by the fourth prism inclined surface 17B2 with respect to the Y-axis direction in the second prism 17B is smaller than the inclination angle θ4 formed by the third prism inclined surface 17B1 with respect to the Y-axis direction, the light refracted by the fourth prism inclined surface 17B2 and directed toward the third prism inclined surface 17B1 is more likely to return to the first prism sheet 16 side through the third prism inclined surface 17B1 than when the same angle or the size of the angle is assumed to be in an opposite relationship. As a result, the amount of light (hereinafter referred to as returning light) returning from the second prism sheet 17 to the first prism sheet 16 side increases. The returning light reaches the second prism sheet 17 again by reflection in the backlight device 12, and rises and exits through any one of a pair of inclined surfaces 17B1 and 17B2 in the second prism 17B, thereby improving the light utilization efficiency. Since the optical path of the returning light from the second prism sheet 17 to the return becomes complicated, the rising angle given by the second prism 17B also becomes diversified, thereby improving the viewing angle characteristics. As described above, it is possible to achieve an improvement in the viewing angle characteristics and brightness.

[0043] Next, the detailed structure of the third light guide plate 14 is described. Figure 4 and Figure 5 As shown, 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. Figure 5 As shown, the first light guide plate lens 32 is arranged on the third light guide plate light emitting 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 them are arranged along the X-axis direction. In the present embodiment, the first light guide plate lens 32 is a so-called double convex lens. The first light guide plate lens 32 is convex and protrudes from the third light guide plate light emitting main surface 14B to the surface side. Specifically, the first light guide plate lens 32 is formed into a semi-cylindrical shape whose cross-sectional shape cut along the X-axis direction is semicircular and extends linearly along the Y-axis direction, and its surface is a first arc-shaped surface 32A. When the angle formed by the tangent at the base end of the first arc-shaped surface 32A and the X-axis direction is set as the "contact angle", the contact angle of the first light guide plate lens 32 is set to, for example, about 62°. The contact angles, width dimensions (arrangement intervals) and height dimensions of the plurality of first light guide plate lenses 32 arranged along the X-axis direction are all substantially the same. To integrally set the first light guide plate lens 32 of this structure on the third light guide plate 14, for example, the third light guide plate 14 can be manufactured by injection molding, and a transfer shape for transferring the first light guide plate lens 32 can be formed in advance on the molding surface of the molding mold for molding the third light guide plate light emitting main surface 14B.

[0044] like Figure 5 As shown, the second light guide plate lens 33 is arranged on the third opposite main 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 the second light guide plate lenses 33 are arranged along the X-axis direction. In the present embodiment, the second light guide plate lens 33 is a convex prism protruding from the third opposite main surface 14C to the back side. Specifically, the second light guide plate lens 33 is formed so that the cross-sectional shape cut along the X-axis direction is roughly triangular (roughly mountain-shaped) and extends straight along the Y-axis direction. The width dimension (dimension in the X-axis direction) of the second light guide plate lens 33 is fixed over the entire length range in the Y-axis direction. The cross-sectional shape of the second light guide plate lens 33 is roughly an isosceles triangle, and the second light guide plate lens 33 has a pair of first light guide plate inclined surfaces 33A. The vertex angle of the second light guide plate lens 33 is preferably set to an obtuse angle (an angle exceeding 90°), specifically, in the range of 100° to 150°, and most preferably 140°. The vertex angles, width dimensions (arrangement intervals) and height dimensions of the plurality of second light guide plate lenses 33 arranged along the X-axis direction are all substantially the same. In this embodiment, the arrangement intervals of the second light guide plate lenses 33 are greater than the arrangement intervals of the first light guide plate lenses 32. To integrally set the second light guide plate lenses 33 of such a configuration on the third light guide plate 14, for example, the third light guide plate 14 can be manufactured by injection molding, and a transfer shape for transferring the second light guide plate lenses 33 is preliminarily formed on the molding surface for molding the third light guide plate light emitting main surface 14B in the molding mold.

[0045] According to the third light guide plate 14 constructed in this way, Figure 5 As shown, the light propagating in the third light guide plate 14 is repeatedly reflected by irradiating the first arc-shaped surface 32A of each first light guide plate lens 32 on the side of the light emitting main surface 14B of the third light guide plate in the Z-axis direction, and moves roughly in a zigzag shape along the X-axis direction. On the other hand, the light propagating in the third light guide plate 14 is repeatedly reflected by irradiating the first light guide plate inclined surface 33A of a pair of second light guide plate lenses 33 on the side of the third opposite main surface 14C in the Z-axis direction, and moves roughly in a zigzag shape along the Y-axis direction. As a result, the expansion of the light propagating in the third light guide plate 14 in the X-axis direction is limited, so it is not easy to produce uneven brightness between the vicinity of the third LED 13 and its surroundings in the X-axis direction.

[0046] like Figure 4 As shown, the third light guide plate lens 34 is arranged on the third opposite main surface 14C of the third light guide plate 14. A plurality of third light guide plate lenses 34 are arranged at intervals along the Y-axis direction. The third light guide plate lens 34 protrudes from the third opposite main surface 14C toward the back side along the Z-axis direction. The third light guide plate lens 34 has: a second light guide plate inclined surface 34A, which is arranged on the opposite side of the third LED 13 side in the Y-axis direction ( Figure 4The third light guide plate inclined surface 34B is arranged on the side of the third LED 13 in the Y-axis direction ( Figure 4 and a fourth light guide plate inclined surface 34C, which is 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 a Y-axis direction from the third LED 13 side ( Figure 4 to the left side) to the opposite side ( Figure 4 The third light guide plate inclined surface 34B has an inclination rising from the opposite side of the third LED 13 side in the Y-axis direction of the third light guide plate 14 ( Figure 4 The right side) to the third LED13 side ( Figure 4 The fourth light guide plate inclined surface 34C has a slope rising from the third LED 13 side ( Figure 4 to the left side) to the opposite side ( Figure 4 right side) with an ascending slope.

[0047] like Figure 4 As shown, the second light guide plate inclined surface 34A and the third light guide plate inclined surface 34B reflect the light propagating in the third light guide plate 14, and make it rise toward the surface side in a manner close to the Z-axis direction, thereby promoting the emission from the third light guide plate main light emitting surface 14B. Therefore, it can be said that the plurality of 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", which reflects the light existing in the third light guide plate 14 to promote the light emission. Specifically, the second light guide plate inclined surface 34A mainly plays the role of reflecting the light traveling in the Y-axis direction away from the third LED 13 to make it rise. On the other hand, the third light guide plate inclined surface 34B mainly plays the role of reflecting the light traveling in the Y-axis direction close to the third LED 13 to make it rise. The second light guide plate inclined surface 34A has a slope such that the further away from the third LED 13 in the Y-axis direction, the smaller the distance from the third light guide plate main light emitting surface 14B (the portion where the third light guide plate lens 34 is not provided). The inclination angle of the second light guide plate inclined surface 34A relative to the Y-axis direction is, for example, about 8°. The third light guide plate inclined surface 34B has a slope such that the further away from the third LED 13 in the Y-axis direction, the larger the distance from the third light guide plate main light emitting surface 14B, that is, the opposite slope to the second light guide plate inclined surface 34A. The third light guide plate inclined surface 34B is formed to have an inclination angle relative to the Y-axis direction of, for example, about 80°, which is close to a vertical slope and is larger than the inclination angle of the second light guide plate inclined surface 34A.

[0048] In addition, if Figure 4 , Figure 6 and Figure 7As shown, the plurality of third light guide plate lenses 34 arranged along the Y-axis direction are designed so that the further away from the third LED 13 in the Y-axis direction, the greater the height dimension (dimension in the Z-axis direction) and the length dimension (dimension in the Y-axis direction) are. In more detail, when the third light guide plate lens 34 close to the third LED 13 in the Y-axis direction is compared with the third light guide plate lens 34 far away from the third LED 13 in the Y-axis direction, the latter has a larger area of ​​the second light guide plate inclined surface 34A and the third light guide plate inclined surface 34B than the former. Thus, although the light is difficult to be irradiated on 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 on the side close to the third LED 13 in the Y-axis direction and the light emission is suppressed, the light is easily irradiated on 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 on the side far away from the third LED 13 in the Y-axis direction to promote the light emission. As a result, the amount of light emitted from the light emitting main surface 14B of the third light guide plate is made uniform on the third LED 13 side and the opposite side thereof in the Y-axis direction.

[0049] like Figure 4 As shown, in the fourth light guide plate inclined surface 34C, the side opposite to the third LED 13 side in the Y-axis direction ( Figure 4 The end portion on the right side of the LED 13 in the Y-axis direction is connected to the second light guide plate inclined surface 34A. Figure 4The end of the fourth light guide plate inclined surface 34C (on the left side) is connected to the third light guide plate inclined surface 34B. The fourth light guide plate inclined surface 34C has a slope in which the distance from the third light guide plate light emitting main surface 14B (the portion where the third light guide plate lens 34 is not provided) increases as it is further away from the third LED 13 in the Y-axis direction. In other words, the fourth light guide plate inclined surface 34C is formed to have the same slope as the third light guide plate inclined surface 34B. The inclination angle of the fourth light guide plate inclined surface 34C relative to the Y-axis direction is, for example, set to 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 constructed in this way reflects the light traveling in the third light guide plate 14 in a manner away from the third LED 13, thereby directing the light toward the third light guide plate light emitting main surface 14B side, but the incident angle of the light relative to the third light guide plate light emitting main surface 14B does not exceed the critical angle. Therefore, the light is totally reflected by the main light emitting surface 14B of the third light guide plate, and is guided to be further away from the third LED 13. As a result, the outgoing light from the main light emitting surface 14B of the third light guide plate is not easily deflected to the side of the third LED 13 in the Y-axis direction. As described above, the third light guide plate 14 is constructed in such a way that the inclination angle relative 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. In addition, the plurality of fourth light guide plate inclined surfaces 34C arranged along the Y-axis direction are designed so that the length dimension becomes smaller as they are away from the third LED 13 in the Y-axis direction. This is because the length dimension of the third light guide plate lens 34 becomes larger as it is farther away from the third LED 13 in the Y-axis direction, and the occupied range of the third light guide plate lens 34 becomes larger.

[0050] like Figure 4 , Figure 6 and Figure 7 As shown, the third light guide plate lens 34 of the above-mentioned structure is configured to be sandwiched between two adjacent second light guide plate lenses 33 in the X-axis direction. Therefore, the third light guide plate lens 34 is configured to be alternately and repeatedly arranged with the second light guide plate lenses 33 in the X-axis direction. The maximum value of the protruding dimension (height dimension) of the third light guide plate lens 34 protruding from the third opposite main surface 14C is smaller than the protruding dimension of the second light guide plate lens 33 also protruding from the third opposite main surface 14C. Therefore, even if the third light guide plate lens 34 is located on the side farthest from the third LED 13 in the Y-axis direction, it will not protrude to the back side more than the second light guide plate lens 33.

[0051] Next, the structure of the first grid 18 will be described. Figure 1As shown, the main surface of the first grid 18 is parallel to the main surfaces of the liquid crystal panel 11 and the third light guide plate 14, and is in a sheet shape. In addition, the main surface of the first grid 18 is parallel to the X-axis direction and the Y-axis direction, and the normal direction (thickness direction) of the main surface is consistent with the Z-axis direction. The first grid 18 has the function of limiting the range of the emission angle of light in the X-axis direction. The top view size of the first grid 18 is the same as the top view size of the third light guide plate 14, the first prism sheet 16 and the second prism sheet 17. The first grid 18 is configured to overlap at least the entire area of ​​the display area AA when viewed from above. The first grid 18 has a first grid light incident main surface (seventh main surface) 18A on the back side and a first grid light emitting main surface (sixth main surface) 18B on the surface side. The first grid light incident main surface 18A is configured toward the third light guide plate light emitting main surface 14B of the third light guide plate 14, and is opposite to the main surface on the surface side (light emitting side) of the second prism sheet 17. The first grid light output main surface 18B is opposed to a first light guide plate opposite main surface 27C of a first light guide plate 27 to be described later.

[0052] like Figure 5As shown, the first grille 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, for example, a light-shielding resin material (light-shielding material) that is black and blocks light. The first light-shielding portion 18C is in the form of a layer extending along the Y-axis direction and the Z-axis direction, and a plurality of the first light-transmitting portions 18D are arranged 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 substantially transparent and transmits light. The first light-transmitting portion 18D is in the form of a layer extending along the Y-axis direction and the Z-axis direction, and a plurality of the first light-transmitting portions 18D are arranged at intervals in the X-axis direction. A plurality of the first light-shielding portions 18C and the first light-transmitting portions 18D are arranged alternately and repeatedly in the X-axis direction. Therefore, the first light-transmitting portion 18D is between two first light-shielding portions 18C that are adjacent to each other at intervals in the X-axis direction, and the first light-shielding portion 18C is between two first light-transmitting portions 18D that are adjacent to each other at intervals in the X-axis direction. Light incident on the first grille light incident main surface 18A of the first grille 18 is transmitted through the first light-transmitting portion 18D disposed between two first light-shielding portions 18C adjacent in the X-axis direction, and is emitted from the first grille light-emitting main surface 18B. The emission angle of the light emitted from the first grille light-emitting main surface 18B in the X-axis direction is limited by the two first light-shielding portions 18C adjacent in the X-axis direction. In addition, the emission angle of the light emitted from the first grille light-emitting main surface 18B in the Y-axis direction is not limited by the first grille 18. The emission angle range of the light emitted from the first grille light-emitting main surface 18B in the X-axis direction is defined by two straight lines that obliquely connect the ends of the two first light-shielding portions 18C sandwiching the first light-transmitting portion 18D in the Z-axis direction. The emission angle range of the light transmitted from the first light-transmitting portion 18D in the X-axis direction varies according to the ratio of the width W1 to the height H1 of the first light-transmitting portion 18D. In addition, the first grid 18 has a pair of sheet carriers that sandwich and carry the plurality of first light shielding portions 18C and the plurality of first light transmitting portions 18D from the front side and the back side. The sheet carriers are made of a substantially transparent light-transmitting resin material. The sheet carriers extend over the entire area of ​​the first grid 18 and hold the plurality of first light shielding portions 18C and the plurality of first light transmitting portions 18D together.

[0053] Specifically, if Figure 5As shown, the ratio of the width W1 of the first light-transmitting portion 18D in the first grille 18 divided by the height H1 is equal to "tan10°". In this way, the absolute value of the maximum value of the angle formed by the light transmitted through the first light-transmitting portion 18D relative to the Z-axis direction is, for example, 10°. Assuming that the range of the emission angle of the emitted light of the backlight device 12 is sufficiently narrowed compared to the case where the ratio of the width of the first light-transmitting portion 18D divided by the height is greater than "tan10°". As a result, the display image of the second display portion AA2 located in front of the passenger seat in the display area AA cannot be visually recognized at least from the driver's seat, which is preferred in terms of limiting the viewing angle. In addition, assuming that the amount of light shielded by the first light-shielding portion 18C is reduced compared to the case where the ratio of the width of the first light-transmitting portion 18D divided by the height is less than "tan10°", the light utilization efficiency is improved.

[0054] Next, the structure of the second backlight device 12U2 is described. Figure 1 and Figure 2 As shown, the second backlight unit 12U2 includes at least a second LED (second light source) 20 and a second light guide plate 21 for guiding light from the second LED 20 .

[0055] like Figure 1 As shown, the second LED 20 is substantially block-shaped, and one of the pair of faces along the Y-axis direction and the Z-axis direction becomes the second light-emitting face 20A. Figure 3 As shown, a plurality of second LEDs 20 are arranged 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 with a sealing material on a substrate portion mounted on the LED substrate. The LED chip provided by the second LED 20 emits, for example, monochromatic blue light. Phosphors are dispersed in the sealing material provided by the second LED 20. The phosphors contained in the sealing material include yellow phosphors, green phosphors, red phosphors, and the like. The second LED 20 provided with such an LED chip and a sealing material emits white light as a whole.

[0056] The second light guide plate 21 is made of a synthetic resin material (such as acrylic resin such as PMMA) having a refractive index sufficiently higher than that of air and being substantially transparent. Figure 1As shown, the second light guide plate 21 is formed in a plate shape, and its main surface is parallel to and overlaps with the main surface of the liquid crystal panel 11. In addition, 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 is consistent with the Z-axis direction. The second light guide plate 21 is configured to overlap with at least the entire area of ​​the display area AA when viewed from above. The second light guide plate 21 is arranged along the X-axis direction (first direction) relative to the second LED 20, and is arranged along the Z-axis direction relative to the liquid crystal panel 11, the third light guide plate 14 and the first grid 18. The second light guide plate 21 is configured on the other side of the X-axis direction (the first direction) relative to the second LED 20. Figure 1 ). That is, if Figure 3 As shown, the positional relationship between the second light guide plate 21 and the second LED 20 (positional relationship arranged along the X-axis direction) and the positional relationship between the third light guide plate 14 and the third LED 13 (positional relationship arranged along the Y-axis direction) are orthogonal. In this way, the third LED 13 and the second LED 20 are dispersedly arranged when viewed from above, so even if the third LED 13 and the second LED 20 are lit separately, heat is difficult to accumulate.

[0057] like Figure 1As shown, one of the outer peripheral end faces of the second light guide plate 21 is set as a second light incident end face (second end face) 21A opposite to the second light emitting surface 20A of the second LED 20. The second light incident end face 21A is a face parallel to the second light emitting surface 20A of the second LED 20, and the second light incident end face 21A is incident with light emitted from the second light emitting surface 20A. In this way, in the second light guide plate 21, the second LED 20 is arranged only on a single side in the X-axis direction. Therefore, the second backlight source unit 12U2 is an edge light type with single-side light input. The main surface on the surface side opposite to the diffuser 12S in a pair of main surfaces of the second light guide plate 21 becomes the second light guide plate output main surface (third main surface) 21B from which the light guided inside is output. The main surface on the back side opposite to the first light guide plate light emitting main surface 27B of the first light guide plate 27 described later among the pair of main surfaces of the second light guide plate 21 is a second opposite main surface (fourth main surface) 21C located on the opposite side to the second light guide plate light emitting main surface 21B. The second opposite main surface 21C of the second light guide plate 21 is arranged toward the first light guide plate 27 in the Z-axis direction. Moreover, the second light guide plate 21 can introduce light emitted from the second LED 20 toward the second light guide plate 21 from the second light incident end surface 21A, and after the light propagates inside, it is emitted upwardly from the second light guide plate light emitting main surface 21B along the Z-axis direction toward the diffuser 12S (liquid crystal panel 11) on the surface side (light emitting side). In addition, the second light guide plate 21 can introduce the emitted light from the first light guide plate 27 from the second opposite main surface 21C, and emit the light from the second light guide plate light emitting main surface 21B toward the diffuser 12S on the surface side. In addition, the normal direction of the second light incident end surface 21A coincides with the X-axis direction (the arrangement direction of the second LEDs 20 and the second light guide plate 21 ).

[0058] like Figure 4 and Figure 5 As shown, a fourth light guide plate lens 22, a fifth light guide plate lens 23 and a sixth light guide plate lens (second lens) 24 are provided on the second light guide plate 21. Figure 4As shown, the fourth light guide plate lens 22 is arranged on the second light guide plate light emitting 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 them are arranged along the Y-axis direction. In the present embodiment, the fourth light guide plate lens 22 is a so-called double convex lens. The fourth light guide plate lens 22 is convex and protrudes from the second light guide plate light emitting main surface 21B to the surface side. Specifically, the fourth light guide plate lens 22 is formed into a semi-cylindrical shape whose cross-sectional shape cut along the Y-axis direction is semicircular and extends straight along the X-axis direction, and its surface is a second arc-shaped surface 22A. When the angle formed by the tangent at the base end of the second arc-shaped surface 22A and the Y-axis direction is set as the "contact angle", the contact angle θc1 of the fourth light guide plate lens 22 is set to, for example, about 30°. The contact angle θc1, width dimension (arrangement interval) and height dimension of the plurality of fourth light guide plate lenses 22 arranged along the Y-axis direction are all substantially the same. To integrally set the fourth light guide plate lens 22 of this structure on the second light guide plate 21, for example, the second light guide plate 21 can be manufactured by injection molding, and a transfer shape for transferring the fourth light guide plate lens 22 can be formed in advance on the molding surface of the molding mold for molding the second light guide plate light emitting main surface 21B.

[0059] like Figure 4 As shown, the fifth light guide plate lens 23 is arranged 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 lenses are arranged along the Y-axis direction. In the present embodiment, the fifth light guide plate lens 23 is a convex prism protruding from the second opposite principal surface 21C to the back side. Specifically, the fifth light guide plate lens 23 is formed so that the cross-sectional shape cut along the Y-axis direction is roughly triangular (roughly mountain-shaped) and extends straight along the X-axis direction. The width dimension (dimension in the Y-axis direction) of the fifth light guide plate lens 23 is fixed over the entire length range in the X-axis direction. The cross-sectional shape of the fifth light guide plate lens 23 is roughly an isosceles triangle, and the fifth light guide plate lens 23 has a pair of fifth light guide plate inclined surfaces 23A. The vertex angle θ7 of the fifth light guide plate lens 23 is preferably set to an obtuse angle (an angle exceeding 90°), specifically, in the range of 100° to 150°, and most preferably 140°. The vertex angle θ7, width dimension (arrangement interval) and height dimension of the plurality of fifth light guide plate lenses 23 arranged along the Y-axis direction are all substantially the same. In the present embodiment, the arrangement interval of the fifth light guide plate lenses 23 is greater than the arrangement interval of the fourth light guide plate lenses 22. To integrally set the fifth light guide plate lenses 23 of such a configuration on the second light guide plate 21, for example, the second light guide plate 21 can be manufactured by injection molding, and a transfer shape for transferring the fifth light guide plate lenses 23 can be pre-formed on a molding surface for molding the second opposite main surface 21C in a molding mold.

[0060] like Figure 5As shown, the sixth light guide plate lens 24 is disposed on the second opposite main surface 21C of the second light guide plate 21. A plurality of the sixth light guide plate lenses 24 are arranged at intervals along the X-axis direction. The sixth light guide plate lens 24 protrudes from the second opposite main surface 21C toward the back side along the Z-axis direction. The sixth light guide plate lens 24 has: a sixth light guide plate inclined surface 24A, which is disposed on the opposite side of the second LED 20 side in the X-axis direction ( Figure 5 The left side of the seventh light guide plate is disposed on the side of the second LED 20 in the X-axis direction ( Figure 5 and a first plane 24C, which is 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 a second light guide plate 21 in the X-axis direction from the second LED 20 side ( Figure 5 to the right side) to the opposite side ( Figure 5 The seventh light guide plate inclined surface 24B has an inclination rising from the side opposite to the second LED 20 side in the X-axis direction of the second light guide plate 21 ( Figure 5 left side) toward the second LED 20 side ( Figure 5 The first plane 24C is a plane parallel to the X-axis direction and the Y-axis direction. In addition, the second plane 25 is provided between two adjacent sixth light guide plate lenses 24 in the X-axis direction. Therefore, the sixth light guide plate lenses 24 and the second plane 25 are arranged alternately and repeatedly along the X-axis direction.

[0061] like Figure 5 As shown, the sixth light guide plate inclined surface 24A reflects the light propagating in the second light guide plate 21 and rises toward the surface side, thereby promoting the emission from the second light guide plate main light emitting surface 21B. Therefore, it can be said that the multiple sixth light guide plate lenses 24 having the sixth light guide plate inclined surface 24A constitute a "second light reflecting portion 36", and the "second light reflecting portion 36" reflects the light existing in the second light guide plate 21 to promote the light emission. Specifically, the sixth light guide plate inclined surface 24A mainly plays the role of reflecting the light traveling in the X-axis direction in the second light guide plate 21 in a manner away from the second LED 20 to make it rise. Specifically, as Figure 8As shown, the inclination angle (angle) θ8 of the sixth light guide plate inclined surface 24A relative to the X-axis direction is set to, for example, less than 40°, preferably about 27°. If the inclination angle θ8 of the sixth light guide plate inclined surface 24A relative to the X-axis direction is set to less than 40°, the light can be made to rise in a direction inclined to the opposite side of the second LED 20 side in the X-axis direction relative to the front direction. Therefore, in the outgoing light from the second light guide plate light-emitting main surface 21B, the light on the opposite side of the second LED 20 side in the X-axis direction relative to the Z-axis direction (the normal direction of the second light guide plate light-emitting main surface 21B) is contained more than the light on the second LED 20 side in the X-axis direction. Therefore, if the second LED 20 is turned on, the outgoing light with a brightness angle distribution in which the peak brightness associated with the outgoing light is biased toward the opposite side of the second LED 20 side in the X-axis direction can be provided. In the vehicle-mounted liquid crystal display device 10 involved in this embodiment, it is preferred that the second LED 20 is arranged on the opposite side of the driver's seat side, that is, the passenger seat side, in the X-axis direction.

[0062] On the other hand, Figure 5 As shown, the seventh light guide plate inclined surface 24B can reflect the light traveling in the X-axis direction in a manner close to the second LED 20 to make it rise, or reflect the light traveling in the second light guide plate 21 in a manner away from the second LED 20 in the X-axis direction and guide it further away from the second LED 20. Specifically, as Figure 8 As shown, the inclination angle (angle) θ9 of the seventh light guide plate inclined surface 24B relative to the X-axis direction is set, for example, in the range of 3° to 10°, preferably at 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 constructed in this way, for light that travels in the second light guide plate 21 in a manner close to the second LED 20 in the X-axis direction, if it is irradiated by the seventh light guide plate inclined surface 24B and refracted, it will travel toward the opposite side of the second LED 20 side in the X-axis direction relative to the front direction. As a result, the brightness of the emitted light in the direction inclined relative to the front direction can be further improved. In addition, for light that travels in the second light guide plate 21 in a manner away from the second LED 20 in the X-axis direction, if it is irradiated by the seventh light guide plate inclined surface 24B and refracted, it will be guided in a manner further away from the second LED 20. Thus, the light emitted from the light emitting main surface 21B of the second light guide plate is less likely to deviate toward the second LED 20 side in the X-axis direction.

[0063] like Figure 5As shown, the first plane 24C and the second plane 25 are parallel to the X-axis direction and the Y-axis direction, and the normal direction thereof is consistent with the Z-axis direction. Even if the light emitted from the first light guide plate 27 described later and incident on the second opposite main surface 21C of the second light guide plate 21 is irradiated on either the first plane 24C or the second plane 25, it travels without being refracted. Therefore, compared with the case where 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 in between, and the case where two sixth light guide plate lenses 24 adjacent in the X-axis direction are directly connected without the second plane 25 in between, the generation of side lobe light that travels in a direction inclined toward the opposite side of the second LED 20 side in the X-axis direction relative to the front direction can be suppressed.

[0064] like Figure 8 as well as Fig. 9 As shown, the plurality of sixth light guide plate lenses 24 arranged along the X-axis direction are designed such that the height dimension (dimension in the Z-axis direction) increases as they are further away from the second LED 20 in the X-axis direction, but the arrangement pitch (arrangement interval) in the X-axis direction becomes constant. The width dimension (dimension in the X-axis direction) of the sixth light guide plate inclined surface 24A becomes larger as it is further away from the second LED 20 in the X-axis direction, although the width changes slightly. The width dimension (dimension in the X-axis direction) of the seventh light guide plate inclined surface 24B becomes larger as it is further away from the second LED 20 in the X-axis direction, and its 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 set to be constant regardless of the position in the X-axis direction. The width dimension (dimension in the X-axis direction) of the second plane 25 becomes smaller as it is further 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 of the sixth light guide plate slope 24A, the width of the seventh light guide plate slope 24B, the width of the first plane 24C and the width 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 lens 24 in the X-axis direction is, for example, constant at about 0.114 mm, and the width dimension of the first plane 24C is, for example, constant at 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 is, for example, in the range of 0.002 mm to 0.005 mm, and varies according to the position of the sixth light guide plate lens 24 in the second light guide plate 21 in the X-axis direction. 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 is, for example, in the range of 0.032 mm to 0.005 mm, and varies according to the position of the sixth light guide plate lens 24 in the second light guide plate 21 in the X-axis direction. When the length dimension of the second light guide plate 21 is set to 300 mm, for example, the width dimension of the second plane 25 varies, for example, in the 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 dimension of the sixth light guide plate lens 24 is ensured to be, for example, about 0.002 mm (2 μm) at the minimum value. Thus, the ease of manufacturing the second light guide plate 21 by resin molding can be fully ensured. In order to ensure that the minimum value of the height dimension of the sixth light guide plate lens 24 is about 0.002 mm, it is preferred to set the inclination angle θ9 of the seventh light guide plate inclined surface 24B relative to the X-axis direction to 3° or more. In addition, the inclination angle θ8 of the sixth light guide plate inclined surface 24A relative to the X-axis direction and the inclination angle θ9 of the seventh light guide plate inclined surface 24B relative to the X-axis direction are both set to be constant, regardless of the position of the second light guide plate 21 in the X-axis direction.

[0066] like Figure 4 and Fig. 9 As shown, the sixth light guide plate lens 24 of the above-mentioned structure is configured to be sandwiched between two adjacent fifth light guide plate lenses 23 in the Y-axis direction. Therefore, the sixth light guide plate lens 24 is configured to be alternately and repeatedly arranged with the fifth light guide plate lens 23 in the Y-axis direction. The maximum value of the height dimension (protrusion dimension from the second opposite main surface 21C) of the sixth light guide plate lens 24 is smaller than the height dimension of the fifth light guide plate lens 23. Therefore, even if the sixth light guide plate lens 24 is located on the side farthest from the second LED 20 in the X-axis direction, it will not protrude to the back side more than the fifth light guide plate lens 23.

[0067] Next, the structure of the first backlight device 12U1 is described. Figure 1 and Figure 2 As shown, the first backlight unit 12U1 includes at least a first LED (first light source) 26 and a first light guide plate 27 that guides light from the first LED 26 .

[0068] like Figure 1 As shown, 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 becomes a first light-emitting surface 26A that emits light. Figure 3 As shown, a plurality of first LEDs 26 are arranged at intervals along the Y-axis direction. The first LED 26 is mounted on an LED substrate. The first LED 26 is configured such that an LED chip is sealed using a sealing material on a substrate portion mounted on the LED substrate. The LED chip provided by the first LED 26 emits, for example, monochromatic blue light. Phosphors are dispersed in the sealing material provided by the first LED 26. The phosphors contained in the sealing material include yellow phosphors, green phosphors, red phosphors, and the like. The first LED 26 provided with such an LED chip and a sealing material emits white light as a whole.

[0069] The first light guide plate 27 is made of a synthetic resin material (such as acrylic resin such as PMMA) having a refractive index sufficiently higher than that of air and being substantially transparent. Figure 1 As shown, the first light guide plate 27 is formed in a plate shape, and its main surface is parallel to the main surface of the liquid crystal panel 11. In addition, 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 is consistent with the Z-axis direction. The first light guide plate 27 is configured to overlap at least the entire area of ​​the display area AA when viewed from above. The main surfaces of the first light guide plate 27 and the second light guide plate 21 overlap with each other. The overlapping first light guide plate 27 and the second light guide plate 21 are arranged on the opposite side (surface side) of the third light guide plate 14 side relative to the first grid 18. The first light guide plate 27 is arranged along the X-axis direction (first direction) relative to the first LED 26, and is arranged along the Z-axis direction relative to the liquid crystal panel 11 and the first grid 18. The first light guide plate 27 is arranged on the other side of the X-axis direction ( Figure 1 ). That is, if Figure 3 As shown, the positional relationship between the first light guide plate 27 and the first LED 26 (positional relationship arranged along the X-axis direction) is the same as the positional relationship between the second light guide plate 21 and the second LED 20 (positional relationship arranged along the X-axis direction), and is orthogonal to the positional relationship between the third light guide plate 14 and the third LED 13 (positional relationship arranged along the Y-axis direction). In this way, the third LED 13 and the first LED 26 are dispersedly arranged when viewed from above, so even if the third LED 13 and the first LED 26 are lit separately, heat is difficult to accumulate.

[0070] like Figure 1As shown, one of the outer peripheral end faces of the first light guide plate 27 is set as a first light incident end face (first end face) 27A opposite to the first light emitting surface 26A of the first LED 26. The first light incident end face 27A is a face parallel to the first light emitting surface 26A of the first LED 26, and the first light incident end face 27A is incident with the light emitted from the first light emitting surface 26A. In this way, in the first light guide plate 27, the first LED 26 is arranged only on one side in the X-axis direction. Therefore, the first backlight unit 12U1 is a single-side light incident edge light type. The main surface on the surface side opposite to the second light guide plate 21 of the pair of main surfaces of the first light guide plate 27 becomes the first light guide plate light emitting main surface (first main surface) 27B from which the light guided inside is emitted. The main surface on the back side opposite to the first grille 18 of the pair of main surfaces of the first light guide plate 27 becomes the first opposite main surface (second main surface) 27C located on the side opposite to the first light guide plate light emitting main surface 27B. The first opposite principal surface 27C of the first light guide plate 27 is arranged toward the first grille light emitting principal surface 18B of the first grille 18 in the Z-axis direction. Moreover, the first light guide plate 27 is capable of introducing light emitted from the first LED 26 toward the first light guide plate 27 from the first light incident end surface 27A, and after the light propagates inside, the light is emitted upwardly from the first light guide plate light emitting principal surface 27B toward the second light guide plate 21 (liquid crystal panel 11) on the surface side (light emitting side) along the Z-axis direction. In addition, the first light guide plate 27 is capable of introducing the emitted light from the first grille 18 from the first opposite principal surface 27C, and emitting the light from the first light guide plate light emitting principal surface 27B toward the second light guide plate 21 on the surface side. In addition, the normal direction of the first light incident end surface 27A is consistent with the X-axis direction (the arrangement direction of the first LED 26 and the first light guide plate 27).

[0071] like Figure 4 and Figure 5 As shown, a seventh light guide plate lens 28, an eighth light guide plate lens 29 and a ninth light guide plate lens (first lens) 30 are provided on the first light guide plate 27. Figure 4As shown, the seventh light guide plate lens 28 is arranged on the first light guide plate light emitting 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 them are arranged along the Y-axis direction. In the present embodiment, the seventh light guide plate lens 28 is a so-called double convex lens. The seventh light guide plate lens 28 is convex and protrudes from the second light guide plate light emitting main surface 27B to the surface side. Specifically, the seventh light guide plate lens 28 is formed into a semi-cylindrical shape whose cross-sectional shape cut along the Y-axis direction is semicircular and extends straight along the X-axis direction, and its surface is the third arc-shaped surface 28A. When the angle formed by the tangent at the base end of the third arc-shaped surface 28A and the Y-axis direction is set as the "contact angle", the contact angle θc2 of the seventh light guide plate lens 28 is set to, for example, about 30°. The contact angle θc2, width dimension (arrangement interval) and height dimension of the plurality of seventh light guide plate lenses 28 arranged along the Y-axis direction are all substantially the same. To integrally set the seventh light guide plate lens 28 of this structure on the first light guide plate 27, for example, the first light guide plate 27 can be manufactured by injection molding, and a transfer shape for transferring the seventh light guide plate lens 28 can be pre-formed on the molding surface of the molding mold for molding the second light guide plate main light emitting surface 27B.

[0072] like Figure 4 As shown, the eighth light guide plate lens 29 is arranged 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 them are arranged along the Y-axis direction. In the present embodiment, the eighth light guide plate lens 29 is a convex prism protruding from the first opposite principal surface 27C to the back side. Specifically, the eighth light guide plate lens 29 is formed so that the cross-sectional shape cut along the Y-axis direction is roughly triangular (roughly mountain-shaped) and extends straight along the X-axis direction. The width dimension (dimension in the Y-axis direction) of the eighth light guide plate lens 29 is fixed over the entire length range in the X-axis direction. The cross-sectional shape of the eighth light guide plate lens 29 is roughly an isosceles triangle, and the eighth light guide plate lens 29 has a pair of eighth light guide plate inclined surfaces 29A. The vertex angle θ10 of the eighth light guide plate lens 29 is preferably set to an obtuse angle (an angle exceeding 90°), specifically, set to a range of 100° to 150°, and most preferably set to 140°. The vertex angle θ10, width dimension (arrangement interval) and height dimension of the plurality of eighth light guide plate lenses 29 arranged along the Y-axis direction are all substantially the same. In the present embodiment, the arrangement interval of the eighth light guide plate lenses 29 is greater than the arrangement interval of the seventh light guide plate lenses 28. To integrally set the eighth light guide plate lenses 29 of such a configuration on the first light guide plate 27, for example, the first light guide plate 27 can be manufactured by injection molding, and a transfer shape for transferring the eighth light guide plate lenses 29 can be pre-formed on the molding surface for molding the first opposite main surface 27C in the molding mold.

[0073] like Figure 5As shown, the ninth light guide plate lens 30 is disposed on the first opposite main surface 27C of the first light guide plate 27. A plurality of the ninth light guide plate lenses 30 are arranged at intervals along the X-axis direction. The ninth light guide plate lens 30 protrudes from the first opposite main surface 27C toward the back 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, which is disposed on the opposite side of the first LED 26 side in the X-axis direction ( Figure 5 tenth light guide plate inclined surface 30B, which is arranged on the side of the first LED26 in the X-axis direction ( Figure 5 and a third plane 30C, which is 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 a first light guide plate 27 in the X-axis direction from the first LED 26 side ( Figure 5 to the right side) to the opposite side ( Figure 5 The tenth light guide plate inclined surface 30B has an inclination rising from the side opposite to the first LED 26 side in the X-axis direction of the first light guide plate 27 ( Figure 5 left side) toward the first LED 26 side ( Figure 5 The third plane 30C is a plane parallel to the Y-axis direction and the Y-axis direction. In addition, a fourth plane 31 is provided between two adjacent ninth light guide plate lenses 30 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] like Figure 5As shown, the ninth light guide plate inclined surface 30A reflects the light propagating in the first light guide plate 27 and rises toward the surface side, thereby promoting the emission from the first light guide plate light emitting main surface 27B. Therefore, it can be said that the plurality of ninth light guide plate lenses 30 having the ninth light guide plate inclined surface 30A constitute a "first light reflecting portion 35", which reflects the light existing in the first light guide plate 27 to promote the light emission. Specifically, the ninth light guide plate inclined surface 30A mainly plays a role in reflecting the light traveling in the X-axis direction in the first light guide plate 27 in a manner away from the first LED 26 to make it rise. Specifically, the inclination angle (angle) θ11 of the ninth light guide plate inclined surface 30A with respect to the X-axis direction is set to 40° or less, 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 made to rise in a direction inclined to the opposite side of the first LED 26 side in the X-axis direction relative to the front direction. Therefore, in the outgoing light from the main light emitting surface 27B of the first light guide plate, the light on the opposite side of the first LED 26 side in the X-axis direction relative to the Z-axis direction (the normal direction of the main light emitting surface 27B of the first light guide plate) is contained more than the light on the first LED 26 side in the X-axis direction. Therefore, if the first LED 26 is turned on, it is possible to provide outgoing light with a brightness angle distribution in which the peak brightness associated with the outgoing light is biased toward the opposite side of the first LED 26 side in 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 vehicle-mounted liquid crystal display device 10 involved in this embodiment, it is preferred that the first LED 26 is arranged on the opposite side of the driver's seat side, that is, on the passenger seat side, in the X-axis direction.

[0075] On the other hand, Figure 5As shown, the tenth light guide plate inclined surface 30B can reflect the light that travels in the X-axis direction in a manner close to the first LED 26 to make it rise, or reflect the light that travels in the first light guide plate 27 in a manner away from the first LED 26 in the X-axis direction and guide it further away from the first LED 26. Specifically, the inclination angle (angle) θ12 of the tenth light guide plate inclined surface 30B relative to the X-axis direction is set to a range of 3° to 10°, for example, and is preferably set to 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 configured in this way, for the light that travels in the first light guide plate 27 in a manner close to the first LED 26 in the X-axis direction, if it is irradiated by the tenth light guide plate inclined surface 30B and refracted, it travels to the opposite side of the first LED 26 side in the X-axis direction relative to the front direction. As a result, the brightness of the emitted light in the direction inclined relative to the front direction can be further improved. In addition, if the light traveling in the first light guide plate 27 in a manner away from the first LED 26 in the X-axis direction is refracted by the tenth light guide plate inclined surface 30B, it is guided in a manner further away from the first LED 26. As a result, the light emitted from the first light guide plate light emitting main surface 27B is not easily deflected toward the first LED 26 side 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] like Figure 5 As shown, the third plane 30C and the fourth plane 31 are parallel to the X-axis direction and the Y-axis direction, and the normal direction thereof is consistent with the Z-axis direction. Even if the light emitted from the first grid 18 and incident on the first opposite main surface 27C of the first light guide plate 27 is irradiated on any one of the third plane 30C and the fourth plane 31, it travels without being refracted. Therefore, compared with the case where the ninth light guide plate inclined surface 30A and the tenth light guide plate inclined surface 30B are directly connected without the third plane 30C in between, and the case where the two ninth light guide plate lenses 30 adjacent in the X-axis direction are directly connected without the fourth plane 31 in between, the generation of side lobe light that travels in a direction inclined toward the opposite side of the first LED 26 side in the X-axis direction relative to the front direction can be suppressed.

[0077] like Figure 5 As shown in FIG. 1 , the plurality of ninth light guide plate lenses 30 arranged along the X-axis direction are designed such that the height dimension (dimension in the Z-axis direction) increases as the distance from the first LED 26 in the X-axis direction, but the arrangement pitch (arrangement interval) in the X-axis direction is constant. Figure 8 and Fig. 9The structure of the sixth light guide plate lens 24 shown is roughly the same. The farther away from the first LED 26 the width dimension (dimension in the X-axis direction) of the ninth light guide plate inclined surface 30A is in the X-axis direction, the larger the width becomes, although the width changes slightly. The farther away from the first LED 26 the width dimension (dimension in the X-axis direction) of the tenth light guide plate inclined surface 30B is in the X-axis direction, the larger the width dimension (dimension in the X-axis direction) is, and the increase rate is higher than the increase rate of the ninth light guide plate inclined surface 30A. The width dimension (dimension in the X-axis direction) of the third plane 30C is set to be constant regardless of the position in the X-axis direction. The width dimension (dimension in the X-axis direction) of the fourth plane 31 is farther away from the first LED 26 in the X-axis direction. The arrangement pitch of the ninth light guide plate lens 30 in the X-axis direction 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, for example, constant at about 0.114 mm, and the width dimension of the third plane 30C is, for example, constant at 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 is, for example, in the range of 0.002 mm to 0.005 mm, and varies according to the position of the ninth light guide plate lens 30 in the first light guide plate 27 in the X-axis direction. 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 is, for example, in the range of 0.032 mm to 0.005 mm, and varies according to the position of the ninth light guide plate lens 30 in the first light guide plate 27 in the X-axis direction. When the length dimension of the first light guide plate 27 is set to 300 mm, for example, the width dimension of the fourth plane 31 varies, for example, in the 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 dimension of the ninth light guide plate lens 30 is ensured to be, for example, about 0.002 mm (2 μm) at a minimum value. Thus, the ease of manufacturing the first light guide plate 27 by resin molding can be fully ensured. In order to ensure that the minimum value of the height dimension of the ninth light guide plate lens 30 is about 0.002 mm, it is preferred to set the inclination angle θ12 of the tenth light guide plate inclined surface 30B relative to the X-axis direction to 3° or more. In addition, the inclination angle θ11 of the ninth light guide plate inclined surface 30A relative to the X-axis direction and the inclination angle θ12 of the tenth light guide plate inclined surface 30B relative to the X-axis direction are both set to be constant, regardless of the position of the first light guide plate 27 in the X-axis direction.

[0079] like Figure 4As shown, the ninth light guide plate lens 30 of the above-mentioned structure is configured to be sandwiched between two eighth light guide plate lenses 29 adjacent in the Y-axis direction. Therefore, the ninth light guide plate lens 30 is configured to be alternately and repeatedly arranged with the eighth light guide plate lens 29 in the Y-axis direction. The maximum value of the height dimension (protrusion dimension from the first opposite main 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 if the ninth light guide plate lens 30 is located on the side farthest from the first LED 26 in the X-axis direction, it will not protrude to the back side more than the eighth light guide plate lens 29.

[0080] In addition, if Figure 1 , Figure 2 and Fig.10 As shown, in the first light guide plate 27 and the second light guide plate 21 involved in this embodiment, the formation range of the first light reflecting portion 35 and the second light reflecting portion 36 is set as follows. That is, when the first opposite main surface 27C is divided into a first area A1 overlapping with the first display portion AA1 in the display area AA, and a second area A2 overlapping with the second display portion AA2 in the display area AA and adjacent to the first area A1 in the X-axis direction, the first light reflecting portion 35 is selectively provided in the first area A1 on the first opposite main surface 27C. In other words, the first light reflecting portion 35 is selectively not formed in the second area A2 on the first opposite main surface 27C (especially referring to Figure 1 as well as Fig.10 ). In contrast, when the second opposite main surface 21C is divided into a third area A3 overlapping with the first area A1 (first display portion AA1) and a fourth area A4 overlapping with the second area A2 (second display portion AA2), the second light reflecting portion 36 is provided at least in the fourth area A4 on the second opposite main surface 21C. Specifically, the second light reflecting portion 36 is provided over the third area A3 and the fourth area A4 on the second opposite main surface 21C, and is provided over substantially the entire area of ​​the second opposite main surface 21C. In addition, the area ratio of the first area A1 (third area A3) to the second area A2 (fourth area A4) is set to 1:1, for example.

[0081] In this way, the first light reflecting portion 35 is selectively provided in the first area A1 on the first opposite main surface 27C. Therefore, when the first LED 26 is turned on, Figure 5 and Fig.11 As shown in FIG. 1 , light is emitted from the portion of the first light guide plate light emitting main surface 27B that overlaps with the first area A1, but light is not emitted from the portion that overlaps with the second area A2. On the other hand, the second light reflecting portion 36 is provided on the second opposite main surface 21C over the third area A3 and the fourth area A4, so when the second LED 20 is turned on, Figure 4 and Figure 5As shown in FIG. 1 , light is emitted from the portion of the second light guide plate light emitting main surface 21B that overlaps with the third area A3 and the fourth area A4, that is, substantially the entire area. In addition, regarding the third backlight device 12U3, if the third LED 13 is turned on, as shown in FIG. Figure 5 As shown, when the light emitted from the third light guide plate 14 is emitted from the first grid light emitting main surface 18B, it passes through the first light shielding portion 18C of the first grid 18 and its angle range in the X-axis direction is limited.

[0082] Accordingly, for example, if 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 from the first grille light emitting main surface 18B of the first grille 18 to a restricted angle range; and light selectively emitted from the portion overlapping with the first area A1 in the first light guide plate light emitting main surface 27B of the first light guide plate 27. As a result, in this case, although the emitted light from the portion overlapping with the first area A1 and the third area A3 in the backlight device 12 is not restricted in the emission angle range in the X-axis direction, the emitted light from the portion overlapping with the second area A2 and the fourth area A4 in the backlight device 12 is restricted in the emission angle range in the X-axis direction. Here, in the present embodiment, the first area A1 and the third area A3 overlap with the first display portion AA1 of the display area AA, and the second area A2 and the fourth area A4 overlap with the second display portion AA2 of the display area AA. Therefore, for example, during the driving of the passenger car, the first LED 26 and the third LED 13 are turned on, and the second LED 20 is turned off. As a result, the emission angle range of the light emitted from the portion of the backlight device 12 that overlaps the second area A2 and the fourth area A4 in the X-axis direction is limited, so that the image displayed on the second display unit AA2 in front of the passenger seat is visually recognized by the passenger seat, but cannot be visually recognized from the driver's seat. On the other hand, the emission angle range of the light emitted from the portion of the backlight device 12 that overlaps the first area A1 and the third area A3 in the X-axis direction is not limited, so the image displayed on the first display unit AA1 in front of the driver's seat can be visually recognized 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 not turned on, the emitted light of the backlight device 12 includes: light emitted from the first grille light emitting main surface 18B of the first grille 18 to a restricted angle range; and light emitted from the second light guide plate light emitting main surface 21B of the second light guide plate 21 throughout the portion overlapping with the third area A3 and throughout the portion overlapping with the fourth area A4. As a result, in this case, the emitted light of the backlight device 12 is not restricted in the emission angle range in the X-axis direction. Here, assuming that the second light reflecting portion 36 is selectively provided in the fourth area A4 on the second opposite main surface 21C, in order to obtain light with an emission angle range that is not restricted in the X-axis direction, it is necessary to light both the first LED 26 and the second LED 20. However, in this case, a dark portion may be visually recognized between the light emitted from the portion of the first light guide plate light emitting main surface 27B overlapping with the first area A1 and the light emitted from the portion of the second light guide plate light emitting main surface 21B overlapping with the fourth area A4. In this regard, in order to obtain light whose emission angle range in the X-axis direction is not restricted, it is sufficient to turn off the first LED 26 and turn on the second LED 20, so it is difficult to visually recognize the dark portion as described above. In addition, in the present embodiment, the first area A1 and the third area A3 overlap with the first display portion AA1 of the display area AA, and the second area A2 and the fourth area A4 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. Therefore, the emission angle range of the light emitted by the backlight device 12 in the X-axis direction is not restricted over substantially the entire area, so any one of the images 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 visually recognized from both the driver's seat and the passenger seat.

[0084] In addition, in this embodiment, if Figure 1As shown, the second light guide plate 21 is arranged with the first light guide plate 27 sandwiched between the second light guide plate 21 and the first grid 18. Here, for example, in the case where the second area A2 in the first opposite main surface 27C of the first light guide plate 27 is damaged, the light propagating in the first light guide plate 27 may be emitted from the portion of the first light guide plate light emitting main surface 27B overlapping with the second area A2 due to the damage. Even in this case, since the second opposite main surface 21C of the second light guide plate 21 is arranged opposite to the first light guide plate light emitting main surface 27B of the first light guide plate 27, it is possible to make it difficult for the light to be emitted from the second opposite main surface 21C by using the second light guide plate 21 to reflect the light emitted from the portion of the first light guide plate light emitting main surface 27B overlapping with the second area A2. In particular, in this embodiment, a fourth light guide plate lens 22 as a double convex lens is provided on the second light guide plate light emitting main surface 21B of the second light guide plate 21, so that the light emitted from the portion overlapping the second area A2 in the first light guide plate light emitting main surface 27B can be well reflected to the back side by the fourth light guide plate lens 22. Thus, when the first LED 26 and the third LED 13 are turned on and the second LED 20 is not turned on, it is possible to prevent the light emitted from the first LED 26 from being inadvertently supplied to the second display portion AA2 of the display area AA.

[0085] like Figure 5 As shown, the plurality of sixth light guide plate lenses 24 constituting the second light reflecting portion 36 are provided in plurality in the third area A3 and the fourth area A4 in the second opposite main surface 21C. Hereinafter, when distinguishing the sixth light guide plate lens 24 and the sixth light guide plate inclined surface 24A, the reference numerals of the configuration configured in the fourth area A4 are marked with α, and the reference numerals of the configuration configured in the third area A3 are marked with β. When the sixth light guide plate lenses 24 are collectively referred to without distinction, the reference numerals are not marked. Among the plurality of sixth light guide plate lenses 24 constituting the second light reflecting portion 36, the sixth light guide plate lens 24α configured in the fourth area A4 has an inclined sixth light guide plate inclined surface (first inclined surface) 24Aα that rises from the side opposite to the second LED 20 toward the second LED 20 side in the X-axis direction. In contrast, among the plurality of sixth light guide plate lenses 24, the sixth light guide plate lens 24β arranged in the third area A3 has a sixth light guide plate inclined surface (second inclined surface) 24Aβ that rises in the X-axis direction from the side opposite to the second LED 20 toward the second LED 20. Since these sixth light guide plate lenses 24α and 24β have the same structure, the inclination angles θ8 formed by these sixth light guide plate inclined surfaces 24Aα and 24Aβ with respect to the X-axis direction are equal.

[0086] According to such a configuration, if the second LED 20 is turned on, the light incident into the second light guide plate 21 is irradiated to the sixth light guide plate inclined surface 24Aα of the sixth light guide plate lens 24α in the fourth area A4 in the second opposite main surface 21C, and is irradiated to the sixth light guide plate inclined surface 24Aβ of the sixth light guide plate lens 24β in the third area A3. The light irradiated to the sixth light guide plate inclined surface 24Aα is reflected and emitted from the portion of the second light guide plate light emitting main surface 21B that overlaps with the fourth area A4. In the emitted light, the light on the opposite side toward the second LED 20 side in the X-axis direction relative to the front direction is contained more than the light on the second LED 20 side in the X-axis direction. The light irradiated to the sixth light guide plate inclined surface 24Aβ is reflected and emitted from the portion of the second light guide plate light emitting main surface 21B that overlaps with the third area A3. In the emitted light, the light on the opposite side of the second LED 20 side in the X-axis direction relative to the front direction is included more than the light on the second LED 20 side in the X-axis direction. Therefore, it is possible to provide emitted light with a brightness angle distribution in which the peak brightness associated with the emitted light from the portion overlapping with the fourth area A4 in the light emitting main surface 21B of the second light guide plate and the peak brightness associated with the emitted light from the portion overlapping with the third area A3 are both biased toward the opposite side of the second LED 20 side in the X-axis direction. Thus, it is possible to fully ensure the brightness of the emitted light in the direction inclined toward the opposite side of the second LED 20 side in the X-axis direction relative to the front direction.

[0087] Moreover, if Figure 5 As shown, the sixth light guide plate inclined surface 24Aβ is set to the same inclination as the sixth light guide plate inclined surface 24Aα. Therefore, when the second LED 20 is turned on, the brightness angle distribution related to the outgoing light from the second light guide plate main light emitting surface 21B shows the same tendency. As a result, it is not easy to produce a local dark part near the boundary between the part overlapping with the third area A3 and the part overlapping with the fourth area A4 in the second light guide plate main light emitting surface 21B. Moreover, the inclination angle θ8 of the sixth light guide plate inclined surface 24Aα and the sixth light guide plate inclined surface 24Aβ relative to the X-axis direction is equal, so that the uniformity of the brightness angle distribution related to the outgoing light from the second light guide plate main light emitting surface 21B when the second LED 20 is turned on becomes higher. As a result, it is less likely to produce a local dark part near the boundary between the part overlapping with the third area A3 and the part overlapping with the fourth area A4 in the second light guide plate main light emitting surface 21B.

[0088] In addition, if Figure 5As shown, 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 which rises in the X-axis direction from the side opposite to the first LED 26 to the first LED 26 side. In this way, the ninth light guide plate inclined surface 30A is set to have the same inclination as the sixth light guide plate inclined surface 24Aα and the sixth light guide plate inclined surface 24Aβ. Therefore, the angular distribution of brightness related to the outgoing light from the first light guide plate light emitting main surface 27B when the second LED 20 is not lit and the first LED 26 is lit has the same tendency as the angular distribution of brightness related to the outgoing light from the second light guide plate light emitting main surface 21B when the first LED 26 is not lit and the second LED 20 is lit. As a result, in the case where the second LED 20 is not lit and the first LED 26 is lit, and in the case where the first LED 26 is not lit and the second LED 20 is lit, the visual effect of the outgoing light of the backlight device 12 is not easy to produce a sense of harmony.

[0089] Next, refer to Fig.12 The block diagram shown in FIG. 1 is used to explain the circuit structure for controlling the driving of the liquid crystal panel 11 and the backlight device 12. Fig.12 As shown, the liquid crystal display device 10 has a control unit 50 that controls the driving of the liquid crystal panel 11 and the backlight device 12. The control unit 50 includes an image signal processing circuit 51, a panel control circuit 52, and a backlight control circuit (light source control unit) 53. The image signal processing circuit 51 processes the image signal provided from the external host system and outputs the processed image signal. The panel control circuit 52 writes an image based on the processed image signal output from the image signal processing circuit 51 to the liquid crystal panel 11. In the case where the liquid crystal display device 10 has 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 adjusts the light emission of the first LED 26, the second LED 20, and the third LED 13 by controlling the first LED 26, the second LED 20, and the third LED 13. When the backlight control circuit 53 controls the first LED 26, the second LED 20, and the third LED 13, for example, PWM (Pulse Width Modulation) dimming can be performed. 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] like Fig.12As shown, the control unit 50 involved in the present embodiment can switch the display in the first display mode (first mode) and the display in the second display mode (second mode) according to the display mode switching signal supplied from the external host system. In the first display mode, the display image of the first display unit AA1 in the display area AA is allowed to be visually recognized from both the driver's seat and the co-driver's seat, while the display image of the second display unit AA2 in the display area AA is allowed to be visually recognized from the co-driver's seat, but the visual recognition from the driver's seat is restricted, which can be said to be a "partial privacy mode". In the second display mode, the display image of the first display unit AA1 and the display image of the second display unit AA2 in the display area AA are allowed to be visually recognized from either the driver's seat or the co-driver's seat, which can be said to be a "full screen public mode". As a trigger for inputting the display mode switching signal, the driving speed of the passenger car equipped with the liquid crystal display device 10 can be used. For example, at the time point when the driving speed of the passenger car is higher than the threshold and at the time point when it is lower than the threshold, the external host system can supply the display mode switching signal to the control unit 50.

[0091] Specifically, when the speed of the passenger car exceeds the threshold, the control unit 50 performs display in the first display mode based on the display mode switching signal supplied from the external host system. When displaying in the first display mode, the backlight control circuit 53 included in the control unit 50 performs display in the first display mode. Figure 1 and Figure 5 As shown, the control is performed so that the first LED 26 and the third LED 13 are turned on and the second LED 20 is not turned on. As a result, the emission angle range of the portion of the backlight device 12 that overlaps the first area A1 and the third area A3 is not limited in the X-axis direction. As a result, the image displayed in the first display unit AA1 that is located in front of the driver's seat and overlaps the first area A1 and the third area A3 can be visually recognized from both the driver's seat and the co-pilot seat. The emission angle range of the portion of the backlight device 12 that overlaps the second area A2 and the fourth area A4 is limited in the X-axis direction. As a result, although the image displayed in the second display unit AA2 that is located in front of the co-pilot seat and overlaps the second area A2 and the fourth area A4 can be visually recognized from the co-pilot seat, it cannot be visually recognized from the driver's seat.

[0092] On the other hand, at a time point when the driving speed of the passenger car is lower than the threshold value, the control unit 50 performs display in the second display mode based on the display mode switching signal supplied from the external host system. When displaying in the second display mode, the backlight control circuit 53 included in the control unit 50 controls the second LED 20 and the third LED 13 to light up and the first LED 26 to not light up. In this way, the emitted light of the backlight device 12 is not restricted in the emission angle range in the X-axis direction throughout substantially the entire area. Thus, any one of the images displayed in the first display unit AA1 located in front of the driver's seat and overlapping the first area A1 and the third area A3 and the images displayed in the second display unit AA2 located in front of the co-pilot seat and overlapping the second area A2 and the fourth area A4 can be visually recognized from both the driver's seat and the co-pilot seat.

[0093] In either the first display mode or the second display mode, the backlight control circuit 53 included in the control unit 50 divides the plurality of third LEDs 13 into the following two groups for driving. Specifically, Figure 1 as well as Figure 3 As shown, the plurality of third LEDs 13 arranged along the X-axis direction (first direction) are grouped into: a plurality of fourth LEDs (fourth light sources) 13α, which are arranged opposite to the portion of the third light guide plate 14 overlapping the first area A1 and the third area A3; and a plurality of fifth LEDs (fifth light sources) 13α, which are arranged opposite to the portion of the third light guide plate 14 overlapping the second area A2 and the fourth area A4. Hereinafter, in the case of distinguishing the third LEDs 13, the reference numeral of the "fourth LED" is marked with a suffix α, and the reference numeral of the "fifth LED" is marked with a suffix β. In the case of collectively referring to the third LEDs 13 without distinction, no suffix is ​​marked on the reference numeral.

[0094] Moreover, if Figure 1 , Figure 3 and Fig.12As shown, even if the display grayscale in the first display portion AA1 is the same as the display grayscale in the second display portion AA2, the backlight control circuit 53 controls in such a way that the light emission per unit time of the fourth LED 13α is greater than the light emission per unit time of the fifth LED 13β. The "display grayscale in the first display portion AA1" mentioned here is the same as the amount of emitted light from the portion overlapping with the first area A1 and the third area A3 in the backlight device 12. Similarly, the "display grayscale in the second display portion AA2" mentioned here is the same as the amount of emitted light from the portion overlapping with the second area A2 and the fourth area A4 in the backlight device 12. In addition, in the case where the display grayscale in the second display portion AA2 is lower than the display grayscale in the first display portion AA1, there may be a case where the backlight control circuit 53 controls so that the light emission per unit time of the fourth LED 13α is equal to the light emission per unit time of the fifth LED 13β.

[0095] like Figure 1 and Figure 3As shown, the light emitted from the plurality of third LEDs 13, when emitted from the third light guide plate light emitting main surface 14B of the third light guide plate 14, is transmitted through the first light guide plate 27 and the second light guide plate 21 to be emitted to the outside. Here, the light emitted from the portion of the third light guide plate light emitting main surface 14B overlapping with the second area A2 and the fourth area A4, when incident on the fourth area A4 in the second opposite main surface 21C of the second light guide plate 21, may be refracted by the second light reflecting portion 36. However, when the above-mentioned emitted light is incident on the second area A2 in 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 area A2, and the second area A2 is almost flat, so that almost no refraction occurs. In contrast, light emitted from the portion of the third light guide plate light emitting main surface 14B overlapping with the first area A1 and the third area A3 may be refracted by the first light reflecting portion 35 when incident on the second area A2 of the first opposite main surface 27C of the first light guide plate 27, and may be refracted by the second light reflecting portion 36 when incident on the fourth area A4 of the second opposite main surface 21C of the second light guide plate 21. Therefore, light emitted from the portion of the third light guide plate light emitting main surface 14B overlapping with the first area A1 and the third area A3 tends to be more easily diffused than light emitted from the portion of the third light guide plate light emitting main surface 14B overlapping with the second area A2 and the fourth area A4, and the amount of light emitted from the portion of the backlight device 12 overlapping with the first area A1 and the third area A3 tends to be less than the amount of light emitted from the portion of the backlight device 12 overlapping with the second area A2 and the fourth area A4. In this regard, even if the display grayscale in the first display portion AA1 is the same as the display grayscale in the second display portion AA2, the backlight control circuit 53 makes the light emission per unit time of the fourth LED 13α that supplies light to the portion of the third light guide plate light emitting main surface 14B that overlaps the first area A1 and the third area A3 greater than the light emission per unit time of the fifth LED 13β that supplies light to the portion of the third light guide plate light emitting main surface 14B that overlaps the second area A2 and the fourth area A4. As a result, it is difficult to produce a difference in the amount of light emitted from the portion of the backlight device 12 that overlaps the first area A1 and the third area A3 and the amount of light emitted from the portion that overlaps the second area A2 and the fourth area A4.

[0096] Next, in order to obtain insights into how the light distribution of the backlight device 12 changes when displaying in the first display mode and when displaying in the second display mode in the liquid crystal display device 10 configured as described above, an empirical experiment 1 was conducted. In the empirical experiment 1, the liquid crystal display device 10 described previously in this paragraph was used, and the brightness of the outgoing light of the backlight device 12 was measured in each case where the backlight control circuit 53 was used to control the first LED 26 and the third LED 13 to be turned on and the second LED 20 to be turned off for displaying in the first display mode, and the backlight control circuit 53 was used to control the second LED 20 and the third LED 13 to be turned on and the first LED 26 to be turned off for displaying in the second display mode, and a graph related to the light distribution (brightness angle distribution) in the X-axis direction was prepared. The brightness measurement was performed on the portion of the backlight device 12 overlapping with the first area A1 and the third area A3 and the portion overlapping with the second area A2 and the fourth area A4.

[0097] The experimental results related to light distribution in empirical experiment 1 are as follows: Fig.13 and Fig.14 As shown. Fig.13 and Fig.14 In the graph related to light distribution shown in the figure, the horizontal axis is the angle of the X-axis direction relative to the front direction (Z-axis direction) (unit: "°"), and the vertical axis is the brightness (unit: "cd / m 2 ”). Fig.13 and Fig.14 The positive and negative signs marked on the angle of the horizontal axis are as follows: “- (negative)” indicates the left side in the X-axis direction relative to the reference 0° (front direction) when the backlight device 12 is observed from the front, and “+ (positive)” indicates the right side in the X-axis direction relative to the reference 0° (front direction) when the backlight device 12 is observed from the front. Fig.13 The light distribution in the case where the first LED 26 and the third LED 13 are turned on and the second LED 20 is not turned on (second display mode) is shown. Fig.13 This is also the light distribution of the emitted light from the portion overlapping the first area A1 and the third area A3 in the backlight device 12 when the second LED 20 and the third LED 13 are turned on and the first LED 26 is not turned on (the first display mode). Fig.14 The luminous intensity distribution of the light emitted from the portion overlapping the second area A2 and the fourth area A4 in the backlight device 12 is shown 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 empirical experiment 1 are described. Fig.13It can be said that the peak brightness is approximately 0°, and the emitted light is mostly biased towards the "-" side, which is an asymmetric light distribution. Specifically, Fig.13 The light distribution is such that the emitted light is deflected to the left side in the X-axis direction, that is, the side opposite to the second LED 20 side, and the emission angle range is about -80° to +20°. Fig.14 It can be said that the peak brightness is approximately 0°, and the light distribution is approximately bilaterally symmetrical. Fig.14 The emission angle range of the light distribution is approximately ±10°. This result can be said to reflect that the light emitted from the third light guide plate 14 as the third LED 13 is turned on passes through the first grid 18, and the emission angle range is limited to approximately ±10°. Fig.14 and Fig.13 In comparison, the emission angle range is extremely narrow. Fig.13 and Fig.14 In comparison, it can be said that the emission angle range is relatively wide, and the emission angle range is not so limited.

[0099] use Fig.15 , the viewing angle characteristics of the first display portion AA1 and the second display portion AA2 in the display area AA of the liquid crystal display device 10 are described. Fig.15 The visual recognition range and light shielding range based on the light emission angle range of the first display unit AA1 and the second display unit AA2 are shown in FIG. In the first display unit AA1, in either the first display mode or the second display mode, the visual recognition range is set to about -80° to +20°, which is similar to Fig.13 In the second display unit AA2, the visual recognition range in the second display mode is about -80° to +20°, which is consistent with Fig.13 The light distribution is consistent with that shown in FIG. 1 , but in the first display mode it is about -10° to +10°, which is different from Fig.14 The light distribution shown is consistent. Therefore, when the display in the second display mode is performed in the liquid crystal display device 10, the image displayed on the first display unit AA1 and the image displayed on the second display unit AA2 can be visually recognized respectively regardless of whether it is in the driver's seat or the front passenger seat. On the other hand, when the display in the first display mode is performed in the liquid crystal display device 10, the image displayed on the first display unit AA1 and the image displayed on the second display unit AA2 can be visually recognized respectively from the front passenger seat, while, although the image displayed on the first display unit AA1 can be visually recognized from the driver's seat, the image displayed on the second display unit AA2 can hardly be visually recognized.

[0100] Next, in order to obtain insights into how the brightness distribution of the backlight device 12 changes when displaying in the first display mode and when displaying in the second display mode in the liquid crystal display device 10 having the above configuration, an empirical experiment 2 was conducted. In this empirical experiment 2, the liquid crystal display device 10 described in the paragraphs before the empirical experiment 1 was used, and the brightness of the outgoing light of the backlight device 12 was measured in each of the cases where the backlight control circuit 53 controlled the first LED 26 and the third LED 13 to be turned on and the second LED 20 not to be turned on for displaying in the first display mode, and the case where the backlight control circuit 53 controlled the second LED 20 and the third LED 13 to be turned on and the first LED 26 not to be turned on for displaying in the second display mode. Specifically, the brightness is measured at predetermined intervals from the left end position in the X-axis direction of the backlight device 12 through the central position to the right end position, and at each position, the brightness of the light emitted from the backlight device 12 at an angle of 0° (front direction) and the brightness of the light emitted from the backlight device 12 at an angle of -45° (diagonally to the left in the X-axis direction) are measured. Based on the measurement results, graphs representing the brightness distribution by shades are prepared for the brightness of the light emitted from the backlight device 12 at an angle of 0° and the brightness of the light emitted from the backlight device 12 at an angle of -45°, and a graph showing the brightness distribution in the X-axis direction is prepared.

[0101] The experimental results of empirical experiment 2 are as follows Figures 16 to 23 shown. Fig.16 , Fig.18 , Fig. 20 and Fig. 22 A graph related to brightness distribution is shown in . Fig.16 , Fig.18 , Fig. 20 and Fig. 22 In the figure, brightness is expressed by shades, and a legend related to the brightness shades is shown (in the legend, the brightness is higher as it is toward the upper side, and the brightness is lower as it is toward the lower side). Fig.17 , Fig.19 , Fig.21 and Fig.23 A graph related to brightness distribution is shown in FIG. Fig.17 , Fig.19 , Fig.21 and Fig.23 In the figure, the horizontal axis is the position in the X-axis direction (unit is "mm"), and the vertical axis is the brightness (unit is "cd / m 2 ”). Fig.17 , Fig.19 , Fig.21 and Fig.23The “position in the X-axis direction” of the horizontal axis takes the central position of the backlight device 12 in the X-axis direction as a reference position (0 mm). Fig.17 , Fig.19 , Fig.21 and Fig.23 The positive and negative signs in the "position in the X-axis direction" of the horizontal axis of the display device indicate the left side in the X-axis direction relative to the reference position, i.e., the first display unit AA1, and the positive and negative signs in the "-(negative)" indicate the right side in the X-axis direction relative to the reference position, i.e., the second display unit AA2. Fig.17 , Fig.19 , Fig.21 and Fig.23 In the horizontal axis of , the position of "-150mm" coincides with the left end position in the X-axis direction, and the position of "+150mm" coincides with the right end position in the X-axis direction.

[0102] Figures 16 to 19 This is the experimental result when the second LED 20 and the third LED 13 are turned on and the first LED 26 is not turned on (second display mode). Fig.16 and Fig.17 is an experimental result of measuring the brightness of light emitted from the backlight device 12 at an angle of 0°. Fig.18 and Fig.19 These are experimental results in which the brightness of light emitted from the backlight device 12 at an angle of −45° was measured. Figure 20 to Figure 23 These are experimental results when the first LED 26 and the third LED 13 are turned on and the second LED 20 is not turned on (first display mode). Fig. 20 and Fig.21 is an experimental result of measuring the brightness of light emitted from the backlight device 12 at an angle of 0°. Fig. 22 and Fig.23 These are experimental results in which the brightness of light emitted from the backlight device 12 at an angle of −45° was measured.

[0103] Explain the experimental results of empirical experiment 2. Figures 16 to 19 It can be seen that when displaying in the second display mode, the brightness distribution of the light emitted from the backlight device 12 at an angle of 0° and the brightness distribution of the light emitted from the backlight device 12 at an angle of -45° both have a substantially high brightness uniformity. Therefore, when displaying in the second display mode, the image displayed by the first display portion AA1 and the image displayed by the second display portion AA2 can be visually recognized from the driver's seat with sufficiently high brightness, and the image displayed by the second display portion AA2 can be visually recognized from the passenger seat with sufficiently high brightness.

[0104] according to Fig. 20 and Fig.21 It can be seen that the brightness distribution of light emitted from the backlight device 12 at an angle of 0° in the case of displaying in the first display mode has the same degree of high brightness uniformity as in the case of displaying in the second display mode. Fig. 22 and Fig.23 It can be seen that when displaying in the first display mode, the brightness distribution of the light emitted from the backlight device 12 at an angle of -45° is biased. Therefore, when displaying in the first display mode, although the image displayed by the first display unit AA1 can be visually recognized from the driver's seat with a sufficiently high brightness, and the image displayed by the second display unit AA2 can be visually recognized from the passenger seat with a sufficiently high brightness, the image displayed by the second display unit AA2 can hardly be visually recognized from the driver's seat side.

[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, at least a portion of its outer peripheral end surface is set as a first light incident end surface (first end surface) 27A that is opposite to the first LED 26 and for light to be incident, and one principal surface of the first light guide plate 27 is set as a first light guide plate light emitting principal surface (first principal surface) 27B from which light is emitted, and the other principal surface is set as a first opposite principal surface (second principal surface) 27C; a second LED (second light source) 20; a second light guide plate 21, at least a portion of its outer peripheral end surface is set as a second light incident end surface (second end surface) 21A that is opposite to the second LED 20 and for light to be incident, and one principal surface of the second light guide plate 21 is set as a second light guide plate light emitting principal surface (third principal surface) 21B from which light is emitted, and the other principal surface is set as a second opposite principal surface (fourth principal surface) 21C; a third LED (third light source) 13; a third light guide plate (optical component) 14, which has a third light incident end face (light incident face) 14A opposite to the third LED (third light source) 13 and for light incidence, and a third light guide plate light emitting main face (fifth main face) 14B for emitting light; and a first grid (first sheet) 18, one main face of which is set as a first grid light emitting main face (sixth main face) 18B, and the other main face is set as a first grid light incident main face (seventh main face) 18A arranged toward the third light guide plate light emitting main face 14B, the main faces of the first light guide plate 27 and the second light guide plate 21 overlap with each other, and are arranged on the opposite side of the third light guide plate 14 relative to the first grid 18, the first grid 18 has at least: two first light shielding portions 18C, the two first light shielding portions 18C are arranged at intervals in a first direction including a direction from the first LED 26 toward the first light guide plate 27, and Blocking light; and a first light-transmitting portion 18D, which is arranged between the two first light-blocking portions 18C and transmits light, and a first light reflecting portion 35 is provided on the first opposite principal surface 27C, the first light reflecting portion 35 reflects light to promote the light output from the light-emitting principal surface 27B of the first light guide plate, and a second light reflecting portion 36 is provided on the second opposite principal surface 21C, the second light reflecting portion 36 reflects light to promote the light output from the light-emitting principal surface 21B of the second light guide plate, when the first opposite principal surface 27C is divided into a first area A1 and a second area A2 adjacent to the first area A1 in the first direction, the first light reflecting portion 35 is selectively arranged in the first area A1 on the first opposite principal surface 27C, and when the second opposite principal surface 21C is divided into a third area A3 overlapping with the first area A1 and a fourth area A4 overlapping with the second area A2, the second light reflecting portion 36 is at least arranged in the fourth area A4 on the second opposite principal surface 21C.

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

[0107] 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 propagates in the second light guide plate 21, is reflected by the second light reflecting portion 36 disposed on the second opposite main surface 21C, and is emitted from the second light guide plate light emitting main surface 21B. The second light reflecting portion 36 is disposed at least in the fourth area A4 on the second opposite main surface 21C, so the light emitted from the second LED 20 is emitted from at least the portion overlapping with the fourth area A4 on the second light guide plate light emitting main surface 21B.

[0108] If the light emitted from the third LED 13 is incident on the third light incident end surface 14A of the third light guide plate 14, it is emitted from the light emitting main surface 14B of the third light guide plate and is incident on the first grille light incident main surface 18A of the first grille 18. The light incident on the first grille light incident main surface 18A of the first grille 18 is transmitted through the first light-transmitting portion 18D arranged between the two first light shielding portions 18C, and is emitted from the first grille light emitting main surface 18B. The emission angle of the light emitted from the first grille light emitting main surface 18B is limited by the two first light shielding portions 18C. The light emitted from the first grille light emitting main surface 18B is transmitted through the first light guide plate 27 and the second light guide plate 21 whose main surfaces overlap each other. The angle range of the light emitted from the first grille light emitting main surface 18B is limited by the first light shielding portion 18C of the first grille 18, so it is difficult to be emitted outside the limited angle range. In this way, if the third LED 13 is turned on, the light can be selectively emitted to the limited angle range.

[0109] For example, if 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 from the first grille light emitting main surface 18B of the first grille 18 to a restricted angle range; and light selectively emitted from the portion of the first light guide plate light emitting main surface 27B of the first light guide plate 27 that overlaps with the first area A1. As a result, in this case, although the emitted light from the portion of the backlight device 12 that overlaps with the first area A1 and the third area A3 is not so restricted in the emission angle range in the first direction, the emitted light from the portion of the backlight device 12 that overlaps with the second area A2 and the fourth area A4 is restricted in the emission angle range in the first direction.

[0110] In addition, the second light reflecting portion 36 is provided on the second opposite main surface 21C throughout the third area A3 and the fourth area A4. Light emitted from the second LED 20 and incident on the second light incident end surface 21A of the second light guide plate 21 propagates within the second light guide plate 21, is reflected by the second light reflecting portion 36 provided on the second opposite main surface 21C, and is emitted from the second light guide plate light emitting main surface 21B. The second light reflecting portion 36 is provided on the second opposite main surface 21C throughout the third area A3 and the fourth area A4 in the first direction, so that the light emitted from the second LED 20 is emitted throughout the portion of the second light guide plate light emitting main surface 21B overlapping with the third area A3 and the portion overlapping with the fourth area A4. For example, if the second LED 20 and the third LED 13 are turned on and the first LED 26 is not turned on, the emitted light of the backlight device 12 includes: light emitted from the first grille light emitting main surface 18B of the first grille 18 to a restricted angle range; and light emitted from the second light guide plate light emitting main surface 21B of the second light guide plate 21 throughout the portion overlapping with the third area A3 and throughout the portion overlapping with the fourth area A4. As a result, in this case, in the first direction, the emission angle range is not so limited by the emission angle range of the emitted light of the backlight device 12. Here, assuming that the second light reflecting portion 36 is selectively provided in the fourth area A4 in the second opposite main surface 21C, in order to obtain light whose emission angle range in the first direction is almost not restricted, it is necessary to light both the first LED 26 and the second LED 20. However, in this case, a dark portion may be visually recognized between the light emitted from the portion of the first light guide plate light emitting main surface 27B overlapping with the first area A1 and the light emitted from the portion of the second light guide plate light emitting main surface 21B overlapping with the fourth area A4. In this regard, in order to obtain light with an emission angle range that is almost unlimited in the first direction, it is sufficient to turn off the first LED 26 and turn on the second LED 20, so it is difficult to visually recognize the dark portion as described above.

[0111] In addition, the first light reflecting portion 35 is composed of a plurality of ninth light guide plate lenses (first lenses) 30 arranged along the first direction on the first opposite main surface 27C, and the second light reflecting portion 36 is composed of a plurality of sixth light guide plate lenses (second lenses) 24 arranged along the first direction on the second opposite main surface 21C, and the sixth light guide plate lens 24α arranged in at least the fourth area A4 among the plurality of sixth light guide plate lenses 24 has a sixth light guide plate inclined surface (first inclined surface) 24Aα inclined in the first direction from the side opposite to the second LED 20 toward the second LED 20 side. Light emitted from the second LED 20 and incident on the second light incident end surface 21A of the second light guide plate 21 is irradiated on the sixth light guide plate inclined surface 24Aα of the sixth light guide plate lens 24α arranged in at least the fourth area A4 on the second opposite main surface 21C during propagation in the second light guide plate 21. Light irradiated to the inclined sixth light guide plate 24Aα having an inclination rising from the side of the second light guide plate 21 opposite to the second LED 20 in the first direction toward the second LED 20 side is reflected and emitted from the portion of the second light guide plate light emitting main surface 21B overlapping at least the fourth area A4. In the emitted light from the portion of the second light guide plate light emitting main surface 21B overlapping at least the fourth area A4, more light on the opposite side of the first direction toward the second LED 20 side relative to the normal direction of the second light guide plate light emitting main surface 21B, that is, the front direction, is included than light on the first direction toward the second LED 20 side. Therefore, when the second LED 20 is turned on, it is possible to provide emitted light with a brightness angle distribution whose peak brightness associated with the emitted light from the portion of the second light guide plate light emitting main surface 21B overlapping at least the fourth area A4 is biased toward the opposite side of the second LED 20 side in the first direction. Thus, the brightness of the emitted light in the direction inclined relative to the front direction can be fully ensured.

[0112] In addition, the sixth light guide plate lens 24β arranged in the third area A3 among the plurality of sixth light guide plate lenses 24 has an inclined sixth light guide plate slope (second slope) 24Aβ that rises in the first direction from the side opposite to the second LED 20 toward the second LED 20 side. In this way, the sixth light guide plate slope 24Aβ is formed to have the same inclination as the sixth light guide plate slope 24Aα. Therefore, when the second LED 20 is turned on, the brightness angle distribution related to the outgoing light from the second light guide plate light emitting main surface 21B shows the same tendency. As a result, it is not easy to produce a local dark portion near the boundary between the portion overlapping with the third area A3 and the portion overlapping with the fourth area A4 in the second light guide plate light emitting main surface 21B.

[0113] In addition, the inclination angles θ8 of the sixth light guide plate inclined surface 24Aα and the sixth light guide plate inclined surface 24Aβ relative to the first direction are equal. This makes the uniformity of the angular distribution of the brightness related to the outgoing light from the second light guide plate light-emitting main surface 21B when the second LED 20 is turned on higher. As a result, it is less likely to produce a local dark portion near the boundary between the portion overlapping with the third area A3 and the portion overlapping with the fourth area A4 in the second light guide plate light-emitting main surface 21B.

[0114] In addition, the positional relationship of the first LED 26 relative to the first light guide plate 27 in the first direction is the same as the positional relationship of the second LED 20 relative to the second light guide plate 21 in the first direction, and the plurality of ninth light guide plate lenses 30 have a ninth light guide plate slope (third slope) 30A that rises in the first direction from the side opposite to the first LED 26 toward the first LED 26 side. In this way, the ninth light guide plate slope 30A is formed to have the same inclination as the sixth light guide plate slope 24Aα. Therefore, the angular distribution of brightness associated with the outgoing light from the first light guide plate main light emitting surface 27B when the second LED 20 is not lit and the first LED 26 is lit has the same tendency as the angular distribution of brightness associated with the outgoing light from the second light guide plate main light emitting surface 21B when the first LED 26 is not lit and the second LED 20 is lit. Thus, when the second LED 20 is not turned on and the first LED 26 is turned on, or when the first LED 26 is not turned on and the second LED 20 is turned on, the visual effect of the light emitted from the backlight device 12 is unlikely to feel unnatural.

[0115] In addition, a backlight control circuit (light source control unit) 53 is provided for controlling the driving of the first LED 26, the second LED 20, and the third LED 13. The backlight control circuit 53 switches, based on the input of a switching signal, between control in 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 control in 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. If the backlight control circuit 53 performs control in the first mode, the first LED 26 and the third LED 13 are turned on and the second LED 20 is turned off. Therefore, although the emission angle range of the emitted light from the portion of the backlight device 12 overlapping the first area A1 and the third area A3 is not so limited in the first direction, the emission angle range of the emitted light from the portion of the backlight device 12 overlapping the second area A2 and the fourth area 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. Therefore, the emission angle range of the light emitted from the backlight device 12 in the first direction is not so limited.

[0116] Furthermore, the second light guide plate 21 is arranged with the first light guide plate 27 sandwiched between the second light guide plate 21 and the first grid 18. In the case where the second area A2 in the first opposite main surface 27C of the first light guide plate 27 is damaged, the light propagating in the first light guide plate 27 may be emitted from the first light guide plate light emitting main surface 27B due to the damage. Even in this case, since the second opposite main surface 21C of the second light guide plate 21 is arranged opposite to the first light guide plate light emitting main surface 27B of the first light guide plate 27, the light emitted from the portion of the first light guide plate light emitting main surface 27B overlapping with the second area A2 can be reflected by the second light guide plate 21, so that it is difficult for the light to be emitted from the second opposite main surface 21C. Thus, the emission of unintentional light can be suppressed.

[0117] In addition, in the optical component, the third light incident end face 14A is composed of a third light guide plate 14 arranged opposite to the third LED 13, and the third light incident end face 14A is composed of at least a portion of the outer peripheral end face of the third light guide plate 14. When the third LED 13 is turned on, light is incident on the third light incident end face 14A in the outer peripheral end face of the third light guide plate 14, and after propagating in the third light guide plate 14, is emitted from the third light guide plate light emitting main surface 14B.

[0118] In addition, a backlight control circuit 53 is provided for controlling 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 extending along the first direction in the outer peripheral end surface of the third light guide plate 14. A plurality of third LEDs 13 are arranged along the first direction. The plurality of third LEDs 13 include: a fourth LED (fourth light source) 13α arranged opposite to the portion of the third light guide plate 14 overlapping the first area A1 and the third area A3; and a fifth LED (fifth light source) 13β arranged opposite to the portion of the third light guide plate 14 overlapping the second area A2 and the fourth area A4. The backlight control circuit 53 makes the light emission per unit time of the fourth LED 13α greater than the light emission per unit time of the fifth LED 13β. When the light emitted from the plurality of third LEDs 13 is emitted from the third light guide plate light emitting main surface 14B of the third light guide plate 14, it is transmitted through the first light guide plate 27 and the second light guide plate 21 to be emitted to the outside. Here, the light emitted from the portion of the third light guide plate main light emitting surface 14B overlapping with the second area A2 and the fourth area 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 main light emitting surface 14B overlapping with the first area A1 and the third area 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 area A2 and the fourth area A4. In this regard, the backlight source control circuit 53 makes the light emission per unit time of the fourth LED 13α that supplies light to the portion of the third light guide plate main light emitting surface 14B overlapping with the first area A1 and the third area A3 greater than the light emission per unit time of the fifth LED 13β that supplies light to the portion of the third light guide plate main light emitting surface 14B overlapping with the second area A2 and the fourth area A4, so that the light emission amount of the backlight source device 12 is less likely to be uneven.

[0119] In addition, the liquid crystal display device (display device) 10 involved in this embodiment includes the backlight device 12 described above and a liquid crystal panel (display panel) 11 that displays using the light from the backlight device 12. According to the liquid crystal display device 10 constructed in this way, in the backlight device 12, the emission angle range of a part of the emitted light is limited, which is preferable in realizing the diversification of display methods.

[0120] <Implementation Method 2> according to Fig.24 or Fig.25 Embodiment 2 of the present invention will be described. Embodiment 2 shows a case where the arrangement of the first backlight device 112U1 and the second backlight device 112U2 in the Z-axis direction is swapped. Note that duplicate descriptions of the same configurations, functions, and effects as those of Embodiment 1 will be omitted.

[0121] like Fig.24 As shown in FIG. 1 , the first backlight device 112U1 of the present embodiment is disposed on the back side of the diffuser 112S. In contrast, the second backlight device 112U2 is disposed on the back side of the first backlight device 112U1 and on the front side of the third backlight device 112U3. Fig.25 As shown, the first light guide plate 127 constituting the first backlight device 112U1 is configured to sandwich the second light guide plate 121 constituting the second backlight device 112U2 between the first light guide plate 127 and the grille 118 constituting the third backlight device 112U3. According to such a configuration, when the first LED 126 is not turned on and the second LED 120 is turned on, light is selectively emitted from the portion of the second light guide plate light emitting main surface 121B of the second light guide plate 121 that overlaps with the fourth area A4. The emitted light is emitted to the outside without passing through the first light guide plate 127, and therefore, can avoid being refracted by the first light guide plate 127.

[0122] As described above, according to the present embodiment, the first light guide plate 127 is arranged with the second light guide plate 121 sandwiched between the first light guide plate 127 and the grille 118. When the first LED 126 is not turned on and the second LED 120 is turned on, light is selectively emitted from the portion of the second light guide plate light emitting main surface 121B of the second light guide plate 121 that overlaps with the fourth area A4. The emitted light is emitted to the outside without passing through the first light guide plate 127, and thus, it is possible to avoid being refracted by the first light guide plate 127.

[0123] <Implementation Method 3> according to Fig.26 or Fig. 27 Embodiment 3 of the present invention will be described. Embodiment 3 shows a case where the configuration of the third backlight unit 212U3 is changed based on Embodiment 1. In addition, repeated descriptions of the same configuration, operation, and effects as those of Embodiment 1 will be omitted.

[0124] like Fig.26 As shown, the third backlight device 212U3 involved in this embodiment is a so-called direct-down type. The third backlight device 212U3 at least includes the same grille 218 as in Embodiment 1, a plurality of third LEDs (third light sources) 38, an LED substrate (light source substrate) 39 on which a plurality of third LEDs 38 are mounted, and an optical component 40 that imparts an optical effect to the light emitted from the third LEDs 38.

[0125] like Fig.26 and Fig. 27As shown, the third LED 38 is a so-called top-emitting type in which the third light-emitting surface 38A is mounted on the LED substrate 39 and faces the opposite side (surface side, optical component 40 side) of the LED substrate 39. The main surface of the LED substrate 39 is parallel to and overlaps with the main surfaces 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 facing the surface side of the main surface of the LED substrate 39, which becomes the mounting surface. In the main surface on the surface 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] like Fig.26 As shown, the optical component 40 includes four sheets stacked on each other in the Z-axis direction. The main surfaces of the plurality of optical components 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 components 40 are, from the back side, a diffuser plate (optical component) 40A, a diffuser sheet 40B, and two prism sheets 40C and 40D.

[0127] like Fig.26 As shown, the diffuser plate 40A is constructed as follows: a plurality of diffusion particles are dispersedly arranged in a substantially transparent resin substrate having a plate thickness thicker than that of the other optical components 40B to 40D, and has the function of diffusing the transmitted light. The main surface on the back side of the diffuser plate 40A is opposite to the third light-emitting surface 38A of the third LED 38, and becomes a light incident surface 40A1 for incident light from the third LED 38. The main surface on the front side of the diffuser plate 40A becomes a light exit surface (fifth main surface) 40A2 for causing light incident from the light incident surface 40A1 to exit toward the front side. It can be said that the plurality of third LEDs 38 are arranged in a planar manner in a manner overlapping the light incident surface 40A1 and the light exit surface 40A2 which are the main surfaces of the diffuser plate 40A. The light exit surface 40A2 of the diffuser plate 40A is arranged toward the grille 218 across the other optical components 40B to 40D. When light emitted from the third light emitting surface 38A of the third LED 38 enters the light incident surface 40A1 of the diffuser plate 40A, it is diffused by the diffusion particles and emitted from the light emitting surface 40A2 to the front side.

[0128] like Fig.26 As shown, the diffusion sheet 40B is composed of a plurality of diffusion particles for diffusing light dispersed in a substantially transparent synthetic resin substrate. The two prism sheets (40C, 40D) are composed of a plurality of prisms extending along the X-axis direction or the Y-axis direction on the main surface of the substantially transparent synthetic resin substrate arranged in a direction (Y-axis direction or X-axis direction) orthogonal to the extending direction thereof, and the two prism sheets give the incident light a function of selectively focusing in the prism arrangement direction. The two prism sheets (40C, 40D) are arranged in a manner that the extending directions of the prisms (the prism arrangement directions) are orthogonal to each other.

[0129] In this embodiment, the backlight control circuit 53 (see Fig.12 ) drives the plurality of third LEDs 38 as follows. That is, the backlight control circuit 53 can control the backlight control circuit 53 according to the display grayscale of the image displayed in the display area AA of the liquid crystal panel 211. Fig.26 and Fig. 27 The amount of light emitted by each of the plurality of third LEDs 38 shown and whether or not they are lit can be controlled. Thus, so-called local dimming control can be realized, and improvement in contrast performance can be achieved.

[0130] Furthermore, the backlight control circuit 53 (see Fig.12 ) In either the first display mode or the second display mode, the plurality of third LEDs 38 are divided into the following two groups for driving. Specifically, Fig.26 and Fig. 27 As shown, the plurality of third LEDs 38 arranged in a matrix are grouped into a plurality of fourth LEDs (fourth light sources) 38α arranged to overlap the first area A1 and the third area A3, and a plurality of fifth LEDs (fifth light sources) 38β arranged to overlap the second area A2 and the fourth area A4. Hereinafter, in the case of distinguishing the third LEDs 38, the reference numeral of the "fourth LED" is suffixed with α, and the reference numeral of the "fifth LED" is suffixed with β. In the case of collectively referring to the third LEDs 38 without distinction, no suffix is ​​added to the reference numeral.

[0131] Moreover, if Fig.26 and Fig. 27 As shown, even if the display grayscale in the first display portion AA1 and the display grayscale in the second display portion AA2 are the same, the backlight control circuit (refer to Fig.12 )53 is also controlled in such a way that the light emission per unit time of the fourth LED 38α is greater than the light emission per unit time of the fifth LED 38β. In addition, when the display grayscale in the second display portion AA2 is lower than the display grayscale in the first display portion AA1, there may also be a situation where the backlight control circuit 53 controls so that the light emission per unit time of the fourth LED 38α is equal to the light emission per unit time of the fifth LED 38β.

[0132] like Fig.26 and Fig. 27As shown, when the light emitted from the plurality of third LEDs 38 is emitted from the light emitting surface 40A2 of the diffuser plate 40A, it is transmitted through the first light guide plate 227 and the second light guide plate 221 to be emitted to the outside. Here, when the light emitted from the portion of the light emitting surface 40A2 overlapping the second area A2 and the fourth area A4 is incident on the fourth area A4 of the second opposite main surface 221C of the second light guide plate 221, it is possible that the light is refracted by the second light reflecting portion 236. However, when the above-mentioned emitted light is incident on the second area 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 area A2, and the second area A2 is almost flat, so that almost no refraction occurs. In contrast, light emitted from the portion of the light emitting surface 40A2 overlapping with the first area A1 and the third area A3 may be refracted by the first light reflecting portion 235 when incident on the second area 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 incident on the fourth area A4 of the second opposite principal surface 221C of the second light guide plate 221. Therefore, light emitted from the portion of the light emitting surface 40A2 overlapping with the first area A1 and the third area A3 tends to be diffused more easily than light emitted from the portion of the light emitting surface 40A2 overlapping with the second area A2 and the fourth area A4, and the amount of light emitted from the portion of the backlight device 212 overlapping with the first area A1 and the third area A3 tends to be less than the amount of light emitted from the portion of the backlight device 212 overlapping with the second area A2 and the fourth area A4. In this regard, even if the display grayscale in the first display portion AA1 is the same as the display grayscale in the second display portion AA2, the backlight control circuit 53 makes the light emission per unit time of the fourth LED 38α that supplies light to the portion of the light emitting surface 40A2 that overlaps the first area A1 and the third area A3 greater than the light emission per unit time of the fifth LED 38β that supplies light to the portion of the light emitting surface 40A2 that overlaps the second area A2 and the fourth area A4. Thus, it is difficult to produce a difference between the light emission amount from the portion of the backlight device 212 that overlaps the first area A1 and the third area A3 and the light emission amount from the portion that overlaps the second area A2 and the fourth area A4.

[0133] As described above, according to the present embodiment, there is provided a backlight control circuit 53 for controlling the driving of the first LED 226, the second LED 220, and the third LED (third light source) 38. A plurality of third LEDs 38 are arranged in a plane so as to overlap with the light exit surface (fifth main surface) 40A2 of the diffuser (optical component) 40A. The light incident surface 40A1 of the diffuser 40A is composed of a main surface on the side opposite to the light exit surface 40A2. The light incident surface 40A1 and the plurality of third LEDs 38 are arranged opposite to each other. When the plurality of third LEDs 38 are lit by the backlight control circuit 53, light is incident on the light incident surface 40A1 on the side opposite to the light exit surface 40A2 of the diffuser 40A, and is given an optical effect by the diffuser 40A and then emitted from the light exit surface 40A2. By controlling the light emission amount of each of the plurality of third LEDs 38 arranged in a plane so as to overlap with the light exit surface 40A2 and whether to light up, the so-called local dimming control can be realized.

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

[0135] <Implementation Method 4> pass Fig.28Embodiment 4 of the present invention will be described. Embodiment 4 shows a case where the configuration of the third backlight unit 312U3 is changed based on Embodiment 1. In addition, repeated descriptions of the same configuration, operation, and effects as those of Embodiment 1 will be omitted.

[0136] like Fig.28 As shown, the third backlight device 312U3 according to the present embodiment is a device that converts the third backlight device 12U3 described in the first embodiment (see Figure 2 ) is rotated 90° around an axis along the Z-axis direction. Specifically, the third backlight device 312U3 is configured such that the arrangement direction of the third LED 313 and the third light guide plate 314 is consistent with the X-axis direction. The third LED 313 is arranged relative to the third light guide plate 314. Fig.28 As shown on the left side. 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 lens 332 of the third light guide plate 314 extends along the X-axis direction, and a plurality of them are arranged in the Y-axis direction. The second light guide plate lens 333 extends along the X-axis direction, and a plurality of them are arranged in the Y-axis direction. A plurality of third light guide plate lenses 334 are arranged at intervals along the X-axis direction.

[0137] like Fig.28 As shown, the first prism sheet 316 constituting the third backlight device 312U3 has a first prism 316B, the cross-sectional shape of the first prism 316B cut along the X-axis direction is roughly triangular and extends linearly along the Y-axis direction. The second prism sheet 317 constituting the third backlight device 312U3 has a second prism 317B, the cross-sectional shape of the second prism 317B cut along the X-axis direction is roughly triangular and extends linearly along the Y-axis direction. The first prism 316B and the second prism 317B can selectively apply a focusing effect to the light from the third light guide plate 314 side in the X-axis direction. In contrast, the arrangement direction of the first light shielding portion 318C and the first light-transmitting portion 318D constituting the grille 318 is consistent with the X-axis direction. Therefore, it can be said that the focusing direction generated by the first prism 316B and the second prism 317B is consistent with the direction of the light emission angle range limited by the grille 318. Thus, the amount of light emitted from the first prism 316B and the second prism 317B absorbed by the first light shielding portion 318C (light loss) while passing through the first light transmitting portion 318D of the grid 318 is reduced, thereby improving light utilization efficiency.

[0138] <Implementation method 5> pass Fig.29Embodiment 5 of the present invention will be described. Embodiment 5 shows a case where the arrangement of the first backlight device 412U1 and the second backlight device 412U2 is changed based on Embodiment 1. Note that duplicate descriptions of the same configurations, functions, and effects as those of Embodiment 1 will be omitted.

[0139] like Fig.29 As shown, the first backlight device 412U1 and the second backlight device 412U2 involved in this embodiment are the first backlight device 412U1 and the second backlight device 412U2 described in the above-mentioned embodiment 1 (see Figure 1 ) is rotated 180° around an axis along the Z-axis direction. The first LED 426 is arranged relative to the first light guide plate 427. Fig.29 The second LED 420 is arranged relative to the second light guide plate 421. Fig.29 Left side shown.

[0140] The passenger car equipped with the liquid crystal display device 410 according to the present embodiment becomes a vehicle in which the driver's seat is located. Fig.29 The passenger seat is located on the right side of Fig.29 The display area AA of the liquid crystal panel 411 is divided into two areas located on the left side of the vehicle, that is, a right-hand drive vehicle. Fig.29 The first display unit AA1 located on the right side and in front of the driver's seat and the Fig.29 The first opposite main surface 427C of the first light guide plate 427 is divided into: Fig.29 and a first area A1 located on the right side of the display unit AA1 and overlapping the first display unit AA1; and Fig.29 Similarly, the second opposite main surface 421C of the second light guide plate 421 is divided into: Fig.29 and a third area A3 located on the right side of the display unit AA1 and overlapping with the first area A1 (first display unit AA1); and Fig.29 A fourth area A4 is located on the left side of the second area A2 (second display portion AA2) and overlaps with the second area A2.

[0141] Furthermore, the first light reflecting portion 435 is selectively disposed on the first opposite main surface 427C. Fig.29 The first area A1 on the right side of the Fig.29 The light distribution related to the light emitted from the first LED 426 and then propagated in the first light guide plate 427 and then ascended by the first light reflecting portion 435 is Fig.13The light distribution shown is reversed left and right. The second light reflecting portion 436 is provided over the third area A3 and the fourth area A4 on the second opposite main surface 421C. The light distribution related to the light emitted from the second LED 420 and then propagated in the second light guide plate 421 and then raised by the second light reflecting portion 436 is similar to Fig.13 The light distribution shown is reversed left and right. Even in this configuration, the same operation and effect as in the first embodiment can be obtained.

[0142] <Implementation Method 6> according to Fig.30 or Fig.31 Embodiment 6 of the present invention will be described. Embodiment 6 shows a case where the configuration of the first backlight unit 512U1 is changed based on Embodiment 1. In addition, repeated descriptions of the same configuration, operation, and effects as those of Embodiment 1 will be omitted.

[0143] like Fig.30 As shown, the first backlight device 512U1 involved in this embodiment further includes a second grid (second sheet) 19 on the basis of the first LED 526 and the first light guide plate 527. The second grid 19 is arranged on the surface side relative to the first light guide plate 527. That is, the second grid 19 is arranged to be sandwiched between the first light guide plate 527 and the second light guide plate 521 in the Z-axis direction. The main surface of the second grid 19 is parallel to the main surfaces of the first light guide plate 527 and the like, and is in the shape of a sheet. In addition, the main surface of the second grid 19 is parallel to the X-axis direction and the Y-axis direction, and the normal direction (thickness direction) of the main surface is consistent with the Z-axis direction. The second grid 19 has the function of limiting the range of the emission angle of light in the X-axis direction. The size of the second grid 19 when viewed from above is the same as the size of the first light guide plate 527 when viewed from above, and the second grid 19 is arranged to overlap at least the entire area of ​​the display area AA when viewed from above. The second grid 19 has a second grid light incident principal surface (ninth principal surface) 19A on the back side and a second grid light emitting principal surface (eighth principal surface) 19B on the front side. The second grid light incident principal surface 19A is arranged toward the first light guide plate light emitting principal surface (first principal surface) 527B of the first light guide plate 527, and is opposite to the first light guide plate light emitting principal surface 527B. The second grid light emitting principal surface 19B is arranged toward the second light guide plate opposite principal surface 521C of the second light guide plate 521, and is opposite to the second light guide plate opposite principal surface 521C.

[0144] like Fig.31As shown, the second grating 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, for example, a light-shielding resin material (light-shielding material) that is black and blocks light. The second light-shielding portion 19C is in the form of a layer extending along the Y-axis direction and the Z-axis direction, and a plurality of the second light-transmitting portions 19D are arranged at intervals in the X-axis direction. The second light-transmitting portions 19D are made of a light-transmitting resin material (light-transmitting material) that is substantially transparent and transmits light. The second light-transmitting portions 19D are in the form of a layer extending along the Y-axis direction and the Z-axis direction, and a plurality of the second light-transmitting portions 19D are arranged at intervals in the X-axis direction. Multiple second light-shielding portions 19C and second light-transmitting portions 19D are arranged alternately and repeatedly in the X-axis direction. Therefore, the second light-transmitting portion 19D is between two second light-shielding portions 19C that are adjacent to each other at intervals in the X-axis direction, and the second light-shielding portion 19C is between two second light-transmitting portions 19D that are adjacent to each other at intervals in the X-axis direction. Light incident on the second grating light incident main surface 19A of the second grating 19 is transmitted through the second light-transmitting portion 19D disposed between two second light-shielding portions 19C adjacent in the X-axis direction, and is emitted from the second grating light-emitting main surface 19B. The emission angle of the emitted light from the second grating light-emitting main surface 19B in the X-axis direction is limited by the two second light-shielding portions 19C adjacent in the X-axis direction. In addition, the emission angle of the emitted light from the second grating light-emitting main surface 19B in the Y-axis direction is not limited by the second grating 19. The emission angle range of the emitted light from the second grating light-emitting main surface 19B in the X-axis direction is defined by two straight lines obliquely connecting the ends of the two second light-shielding portions 19C sandwiching the second light-transmitting portion 19D in the Z-axis direction. The emission angle range of the transmitted light of the second light-transmitting portion 19D in the X-axis direction varies according to the ratio of the width W2 to the height H2 of the second light-transmitting portion 19D. In addition, the second grid 19 has a pair of sheet carriers that sandwich and carry the plurality of second light shielding portions 19C and the plurality of second light-transmitting portions 19D from the front side and the back side. The sheet carriers are made of a substantially transparent light-transmitting resin material. The sheet carriers extend over the entire area of ​​the second grid 19 and hold the plurality of second light shielding portions 19C and the plurality of second light-transmitting portions 19D together.

[0145] Specifically, if Fig.31As shown, the ratio of the width W2 of the second light-transmitting portion 19D in the second grid 19 divided by the height H2 is equal to "tan45°". That is, the width W2 and the height H2 of the second light-transmitting portion 19D are the same value, and the cross-sectional shape cut along the Z-axis direction and the X-axis direction is approximately square. In this way, the absolute value of the maximum value of the angle formed by the light passing through the second light-transmitting portion 19D relative to the Z-axis direction is 45°. The ratio (tan45°) of the width W2 of the second light-transmitting portion 19D divided by the height H2 is greater than the ratio (tan10°) of the width W1 of the first light-transmitting portion 518D of the first grid 518 divided by the height H1. When the Z-axis direction is set to 0°, the emission angle range of the light that passes through the second light-transmitting portion 19D and is emitted from the second grating light-emitting main surface 19B is ±45°, which is a wider angle than the emission angle range (±10°) of the light that passes through the first light-transmitting portion 518D and is emitted from the first grating light-emitting main surface 518B.

[0146] Here, for example, in the case where the second area A2 in the first opposite main surface 527C of the first light guide plate 527 is damaged, the light propagating in the first light guide plate 527 may be scattered due to the damage and emitted from the portion of the first light guide plate main light emitting surface 527B overlapping with the second area A2. In this case, since the second grid 19 is arranged on the surface side of the first light guide plate main light emitting surface 527B, the emission angle range of the light emitted from the portion of the first light guide plate main light emitting surface 527B overlapping with the second area A2 can be limited to within the range of ±45°. Therefore, when the first LED 526 and the third LED 13 (refer to Figure 2 ) is turned on and the second LED 520 is not turned on, even if the light emitted from the first LED 526 and propagating in the first light guide plate 527 is emitted from the portion of the first light guide plate light emitting main surface 527B overlapping with the second area A2 due to the scratches etc. generated in the second area A2 in the first opposite main surface 527C, it is possible to roughly avoid the light being emitted to the angle range (+45° to +90°, -45° to -90°) with an absolute value exceeding 45°. Figure 2 ) is turned on and the second LED 520 is not turned on, it is difficult for the display image of the second display unit AA2 located in front of the passenger seat in the display area AA to be visually recognized from the driver's seat, so the display performance in the "partial privacy mode" is improved. On the other hand, when the second LED 520 and the third LED 13 (refer to Figure 2) is turned on and the first LED 526 is not turned on, the emitted light of the second light guide plate 521 will not be transmitted through the second grille 19, so the emission angle range will not be limited. In contrast, although the emitted light of the third backlight device 512U3 is transmitted through the second light-transmitting portion 19D of the second grille 19 to the outside, since the emission angle range limited by the second grille 19 is wider than that of the first grille 518, almost no light is absorbed by the second light-shielding portion 19C, and the brightness reduction caused by the second grille 19 is almost avoided.

[0147] As described above, according to the present embodiment, the second grid (second sheet) 19 is provided, one main surface of the second grid (second sheet) 19 is set as the second grid light emitting main surface (eighth main surface) 19B, and the other main surface is set as the second grid light incident main surface (ninth main surface) 19A arranged toward the first light guide plate light emitting main surface 527B, and the second grid 19 has at least two second light shielding portions 19C arranged at intervals in the first direction and shielding light, and a second light transmitting portion 19D arranged between the two second light shielding portions 19C and transmitting light. In the case where the second area A2 in the first opposite main surface 527C of the first light guide plate 527 has damage or the like, the light propagating in the first light guide plate 527 may be emitted from the first light guide plate light emitting main surface 527B due to the damage or the like. In this case, since the second grid 19 is arranged so that the second grid light incident main surface 19A faces the first light guide plate light emitting main surface 527B, a portion of the light emitted from the portion of the first light guide plate light emitting main surface 527B overlapping with the second area A2 is absorbed by the second light shielding portion 19C in the process of transmitting through the second light-transmitting portion 19D of the second grid 19. That is, even if light is scattered due to scratches or the like generated in the second area A2 of the first opposite main surface 527C, since the second grid 19 is used to limit the emission angle range, it is possible to suppress unintentional emission light.

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

[0149] (1) The second light guide plate 21-1 may also be Fig.32 The composition shown. Fig.32 In the second light guide plate 21-1 shown in FIG. 1 , the second light reflecting portion 36-1 is selectively provided in the fourth area A4 of the second opposite main surface 21C-1, and is selectively not formed in the third area A3. In such a configuration, when displaying in the second display mode, the backlight control circuit 53 (see FIG. 1 ) Fig.12 ) As long as the first LED 26-1, the second LED 20-1 and the third LED 13 (refer to Figure 3) can be controlled by turning on all lights.

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

[0151] (3) With the change in the configuration of the sixth light guide plate lens 24 as described in (2), the light distribution related to the light emitted from the second LED 20, 120, 220, 320, 420, 520 and 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 is Fig.13 The light distribution shown (asymmetric light distribution) may be different from, for example, a substantially symmetric light distribution, and the emission angle range may be different from -80° to +20°.

[0152] (4) In addition to the above (2), the inclination angles relative to the X-axis direction between the sixth light guide plate inclined surface 24Aα of the sixth light guide plate lens 24α arranged in the fourth area A4 and the sixth light guide plate inclined surface 24Aβ of the sixth light guide plate lens 24β arranged in the third area A3 may also be different from each other. Accordingly, the light distribution associated with the light emitted from the second LED 20, 120, 220, 320, 420, 520 and then propagated in the second light guide plate 21, 121, 221, 321, 421, 521 and then raised by the second light reflecting portion 36, 236, 436 may also be different in the third area A3 and the fourth area A4. For example, the light distribution associated with the light emitted from the fourth area A4 is as follows: Fig.13 As shown in FIG. 1 , on the other hand, the light distribution associated with the outgoing light from the third area A3 may also be such that Fig.13 The light distribution shown is reversed left to right.

[0153] (5) The specific structure of the ninth light guide plate lens 30 constituting the first light reflection portion 35, 235, 435 can be changed as appropriate. For example, the ninth light guide plate inclined surface 30A included in 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) With the change of the structure of the ninth light guide plate lens 30 as described in (5), the light distribution related to the light emitted from the first LED 26, 126, 226, 326, 426, 526 and propagated through the first light guide plate 27, 127, 227, 327, 427, 527 and then ascended by the first light reflecting portion 35, 235, 435 is Fig.13 The light distribution shown (asymmetric light distribution) may be different from, for example, a substantially symmetric light distribution, and the emission angle range may be different from -80° to +20°.

[0155] (7) The first light guide plate main light emitting surface 27B, 527B of the first light guide plate 27, 127, 227, 327, 427, 527 may be formed into a flat shape without forming the seventh light guide plate lens 28 as a double convex lens. Similarly, the second light guide plate main light emitting surface 21B, 121B of the second light guide plate 21, 121, 221, 321, 421, and 521 may be formed into a flat shape without forming the fourth light guide plate lens 22 as a double convex lens. In addition, the third light guide plate main light emitting surface 14B of the third light guide plate 14, 314 may be formed into a flat shape without forming the first light guide plate lens 32, 332 as a double convex lens.

[0156] (8) For example, a third grille may be provided instead of the diffusion sheet 12S disposed on the frontmost surface side. The third grille is a structure in which the first grilles 18, 118, 218, 318, and 518 are rotated 90 degrees around an axis along the Z-axis direction, and the light shielding portions and the light transmitting portions are alternately arranged along the Y-axis direction. By disposing the third grille on the frontmost surface side in the backlight device 12, 212, the emission angle range in the Y-axis direction can be limited, thereby preventing reflection into the windshield of the passenger car.

[0157] (9) In addition to 1:1, the area ratio of the first display area AA1 (first area A1 and third area A3) and the second display area AA2 (second area A2 and fourth area A4) may be changed as appropriate.

[0158] (10) In the configurations described in Embodiments 1, 2, 4, 5, and 6, 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 unit 12U3, 312U3, and 512U3. In addition, other types of optical sheets may be added to the third backlight unit 12U3, 312U3, and 512U3.

[0159] (11) The configuration described in Embodiment 2 can be appropriately combined with the configuration described in any one of Embodiments 3, 4, and 5.

[0160] (12) The number, lamination order, types, etc. of the optical components described in Embodiment 3 may be changed as appropriate.

[0161] (13) The number of display modes may be three or more. For example, a third display mode may be set in which the backlight control circuit 53 turns on the third LED 13, 313 and turns off the first LED 26, 126, 226, 326, 426, 526 and the second LED 20, 120, 220, 320, 420, 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 vertex angles of the second light guide plate lenses 33 and 333, the vertex angle θ7 of the fifth light guide plate lens 23, and the vertex angle θ10 of the eighth light guide plate lens 29 may be changed appropriately.

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

[0164] (16) The specific values ​​of the inclination angles, vertex angles, etc. of the prism slopes 16B1, 16B2, 17B1, 17B2 of the prisms 16B, 17B, 316B, 317B of the prism sheets 16, 17, 316, 317 can be changed as appropriate. The specific materials of the substrates 16A, 17A used in the prism sheets 16, 17, 316, 317 can be changed as appropriate. Similarly, the specific materials used in the prisms 16B, 17B, 316B, 317B can also be changed as appropriate.

[0165] (17) The specific cross-sectional shape of each prism 16B, 17B, 316B, 317B included in each prism sheet 16, 17, 316, 317 can be changed appropriately. In this case, for example, any one of the prism inclined surfaces 16B1, 16B2, 17B1, 17B2 of each prism 16B, 17B, 316B, 317B can be curved in a manner having a plurality of inclination angles.

[0166] (18) In the first grid 18, 118, 218, 318, 518, the specific numerical value of the ratio (tanθ) obtained by dividing the width W1 of the first light-transmitting portion 18D, 318D, 518D by the height H1 can be appropriately changed in addition to tan10°, for example, it can be set to tan12.5°, tan15°, tan17.5°, etc.

[0167] (19) Each LED 13, 20, 26, 120, 126, 220, 226, 313, 320, 326, 420, 426, 520, 526 may be a side-emitting type or a top-emitting type. In addition to LEDs, OLEDs (Organic Light Emitting Diodes) or the like may be used as light sources.

[0168] (20) Instead of the first prism sheet 16, 316 and the second prism sheet 17, 317, a prism sheet in which prisms are provided on one side of the principal surface (light incident principal surface) on the rear side may be used.

[0169] (21) The liquid crystal display device 10 or 410 can also be applied to applications other than vehicle-mounted applications.

[0170] (22) In the second grating 19 described in Embodiment 6, the specific value of the ratio (tanθ) obtained by dividing the width W2 of the second light-transmitting portion 19D by the height H2 can be appropriately changed in addition to tan45°. In this case, the ratio obtained by dividing the width W2 of the second light-transmitting portion 19D by the height H2 is preferably greater than the ratio obtained by dividing the width W1 of the first light-transmitting portion 18D, 318D, 518D by the height H1, but is not limited thereto.

[0171] (23) The structure described in Embodiment 6 (second grid 19) can be appropriately combined with the structures described in Embodiments 2 to 5. Description of Reference Numerals

[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 component), 14A...third light incident end surface (light incident surface), 14B...light emitting main surface of the third light guide plate (fifth main surface )、18, 118, 218, 318, 518…first grid (first sheet), 18A…first grid light incident principal surface (seventh principal surface), 18B, 518B…first grid light emitting principal surface (sixth principal surface), 18C, 318C…first light shielding portion, 18D, 318D, 518D…first light transmitting portion, 19…second grid (second sheet), 19A…second grid light incident principal surface (ninth principal surface), 19B…second grid light emitting principal surface (eighth principal surface), 19C…second light shielding 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 incident end surface (second end surface), 21B, 121B…second light guide plate light emitting 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, 27 A…first light incident end face (first end face), 27B, 527B…first light guide plate light emitting main face (first main face), 27C, 227C, 427C, 527C…first opposite main face (second main face), 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…diffuser plate (optical component), 40A1…light incident surface, 40A2…light emitting surface (fifth main face), 53…backlight source control circuit (light source control portion), A1…first area, A2…second area, A3…third area, A4…fourth area.

Claims

1. A lighting device, characterized in that: include: The first light source; A first light guide plate, wherein at least a portion of its outer peripheral end surface is set as a first end surface opposite to the first light source and for light incidence, and one principal surface of the first light guide plate is set as a first principal surface for light emission, and the other principal surface is set as a second principal surface; Second light source; A second light guide plate, wherein at least a portion of its outer peripheral end surface is set as a second end surface opposite to the second light source and for light incidence, and one principal surface of the second light guide plate is set as a third principal surface for light emission, and the other principal surface is set as a fourth principal surface; The third light source; an optical component having a light incident surface and a fifth main surface, wherein the light incident surface is opposite to the third light source and is for light to be incident on, and the fifth main surface is for light to be emitted; as well as The first sheet has one principal surface set as the sixth principal surface and the other principal surface set as the seventh principal surface arranged toward the fifth principal surface, The main surfaces of the first light guide plate and the second light guide plate overlap with each other, and are arranged on the opposite side of the first sheet to the optical component side. The first sheet material has at least: two first light shielding portions, which are arranged at intervals in a first direction including a direction from the first light source toward the first light guide plate and shield light; as well as a first light-transmitting portion, which is disposed between the two first light-shielding portions and transmits light; A first light reflecting portion is provided on the second main surface, and the first light reflecting portion reflects light to promote light emission from the first main surface. A second light reflecting portion is provided on the fourth main surface, and the second light reflecting portion 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. When the fourth main surface is divided into a third region overlapping the first region and a fourth region overlapping the second region, the second light reflecting portion is provided on the fourth main surface at least in the fourth region.

2. The lighting device according to claim 1, characterized in that: The second light reflecting portion is provided on the fourth main surface over the entire third region and the fourth region.

3. The lighting device according to claim 2, characterized in that: The first light reflecting portion is composed of a plurality of first lenses, and the plurality of first lenses are arranged along the first direction on the second principal surface. The second light reflecting portion is composed of a plurality of second lenses, and the plurality of second lenses are arranged along the first direction on the fourth principal surface. The second lenses arranged in at least the fourth region among the plurality of second lenses have a first inclined surface inclined so as to increase from the side opposite to the second light source toward the second light source side in the first direction.

4. The lighting device according to claim 3, characterized in that: The second lenses arranged in the third region among the plurality of second lenses have an inclined second slope, and the inclination of the second slope is such that it increases from the side opposite to the second light source toward the second light source side in the first direction.

5. The lighting device according to claim 4, characterized in that: The first inclined surface and the second inclined surface have the same inclination angle relative to the first direction.

6. The lighting device according to any one of claims 3 to 5, characterized in that: The positional relationship of the first light source relative to the first light guide plate in the first direction is the same as the positional relationship of the second light source relative to the second light guide plate in the first direction. The plurality of first lenses have an inclined third slope, and the inclination of the third slope is such that it increases from the side opposite to the first light source toward the first light source side in the first direction.

7. The lighting device according to any one of claims 2 to 5, characterized in that: The lighting device includes a light source control unit that controls driving of the first light source, the second light source, and the third light source. The light source control unit switches between control in a first mode and control in a second mode based on an input of a switching signal. In the first mode, the first light source and the third light source are turned on, while the second light source is turned off. In the second mode, the second light source and the third light source are turned on, while the first light source is turned off.

8. The lighting device according to any one of claims 2 to 5, characterized in that: The second light guide plate is arranged with the first light guide plate sandwiched between the second light guide plate and the first sheet.

9. The lighting device according to any one of claims 2 to 5, characterized in that: The first light guide plate is arranged with the second light guide plate sandwiched between the first sheet material and the first light guide plate.

10. The lighting device according to any one of claims 1 to 5, characterized in that: In the optical component, the light incident surface is constituted by at least a portion of an outer peripheral end surface, and the light incident surface is constituted by a third light guide plate disposed to face the third light source.

11. The lighting device according to claim 10, characterized in that: The lighting device includes 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 formed by a portion of the outer peripheral end surface of the third light guide plate extending along the first direction, The third light sources are arranged in a plurality along the first direction. The plurality of third light sources include: a fourth light source disposed opposite to a portion of the third light guide plate that overlaps the first region and the third region; and a fifth light source disposed opposite to a portion of the third light guide plate that overlaps the second region and the fourth region, The light source control unit makes the light emission amount of the fourth light source per unit time greater than the light emission amount of the fifth light source per unit time.

12. The lighting device according to any one of claims 1 to 5, characterized in that: The lighting device includes a light source control unit that controls driving of the first light source, the second light source, and the third light source. A plurality of third light sources are arranged in a planar manner so as to overlap with the fifth main surface. In the optical component, the light incident surface is constituted by a principal surface on the side opposite to the fifth principal surface, and the light incident surface is arranged to face the plurality of third light sources.

13. The lighting device according to claim 12, characterized in that: The plurality of third light sources include: a fourth light source arranged to overlap with the first area and the third area; and a fifth light source, which is arranged to overlap with the second area and the fourth area, The light source control unit makes the light emission amount of the fourth light source per unit time greater than the light emission amount of the fifth light source per unit time.

14. The lighting device according to any one of claims 1 to 5, characterized in that: The lighting device includes a second sheet, one principal surface of the second sheet is set as an eighth principal surface, and the other principal surface is set as a ninth principal surface arranged toward the first principal surface. The second sheet material has at least: two second light shielding portions, the two second light shielding portions are arranged at intervals in the first direction and shield light; as well as The second light-transmitting portion is disposed between the two second light-shielding portions and transmits light.

15. A display device, characterized in that: include: The lighting device according to any one of claims 1 to 5; as well as A display panel performs display using the light from the lighting device.

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