Lighting devices and display devices

Abstract

To provide a lighting device with improved light extraction efficiency. [Solution] The lighting device comprises a first light guide plate and a second light guide plate. The cross-sectional shape of the first light guide plate is a trapezoid with a lower side longer than the upper side. The second light guide plate includes an integrally formed third light guide plate and a first protrusion. The cross-sectional shape of the third light guide plate is a trapezoid with a lower side longer than the upper side. The cross-sectional shape of the first protrusion is a trapezoid with a upper side longer than the lower side. The fourth side of the second light guide plate and the sixth side of the first protrusion, and the integrally formed seventh side, are inclined with respect to the thickness direction, and a reflective member is provided in contact with the seventh side.

Description

【Technical Field】 【0001】 Embodiments of the present invention relate to a lighting device and a display device. 【Background Art】 【0002】 In a laser backlight using an element that emits laser light as a light source, a backlight capable of equalizing the in-plane luminance distribution has been developed. 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 International Publication No. 2013 / 161811 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 This embodiment provides a lighting device with improved light extraction efficiency. By providing such a lighting device, a display device with improved luminance is provided. 【Means for Solving the Problems】 【0005】 A lighting device according to an embodiment includes: a first light guide plate having a first side and a second side provided on the opposite side of the first side, and having a first surface and a second surface provided on the opposite side of the first surface; a second light guide plate provided on the first light guide plate; a light source element provided facing the second light guide plate; a reflector provided facing the first surface of the first light guide plate; an optical sheet provided on the second light guide plate; and the cross-sectional shape of the first light guide plate is a trapezoidal shape with the lower side longer than the upper side, the second light guide plate includes an integrally formed third light guide plate and a first convex portion, The cross-sectional shape of the third light guide plate is a trapezoidal shape in which the lower side is longer than the upper side. The cross-sectional shape of the first protrusion is a trapezoidal shape in which the upper side is longer than the lower side. The third light guide plate has a third side and a fourth side provided on the opposite side of the third side, and a third surface and a fourth surface provided on the opposite side of the third surface. The first protrusion has a fifth side parallel to the second side and a sixth side provided on the opposite side of the fifth side. The second surface of the first light guide plate and the third surface of the third light guide plate face each other. Multiple second protrusions are provided in the first region of the first surface of the first light guide plate. The fourth side of the second light guide plate and the sixth side of the first protrusion form a seventh side that is integrally formed. The seventh edge is inclined with respect to the thickness direction, A reflective member is provided in contact with the seventh side. 【0006】 Furthermore, the lighting device according to one embodiment is A first light guide plate having a first side and a second side on the opposite side of the first side, and a first surface and a second surface on the opposite side of the first surface, A second light guide plate is provided on the first light guide plate, A light source element is provided opposite the second light guide plate, A reflector is provided opposite the first surface of the first light guide plate, Equipped with, The cross-sectional shape of the first light guide plate is a trapezoidal shape in which the lower side is longer than the upper side. The second light guide plate has an integrally formed third light guide plate and a first protrusion, The cross-sectional shape of the third light guide plate is a trapezoidal shape in which the lower side is longer than the upper side. The third light guide plate has a third surface and a fourth surface provided on the opposite side of the third surface, and has a third side and a fourth side provided on the opposite side of the third side, The first protrusion has a second and a third protrusion that are integrally formed with it. The cross-sectional shape of the second protrusion is a trapezoidal shape in which the upper side is longer than the lower side. The second protrusion has a fifth side parallel to the third side and a sixth side provided on the opposite side of the fifth side. The cross-sectional shape of the third protrusion is triangular, The third protrusion has a seventh side parallel to the second side and an eighth side separate from the seventh side. The sixth side of the second protrusion and the eighth side of the third protrusion form a ninth side that is integrally formed. The light source element is provided facing the third side of the third light guide plate, The second surface of the first light guide plate and the third surface of the third light guide plate face each other. Multiple fourth protrusions are provided in the first region of the first surface of the first light guide plate. The fourth and ninth sides form a V-shaped edge. 【0007】 Furthermore, the lighting device according to one embodiment is A light guide plate having a first light guide plate and a second light guide plate, which are integrally formed, A light source element is provided opposite the second light guide plate, A reflector is provided opposite the first light guide plate, Equipped with, The first light guide plate has a first side and a second side provided on the opposite side of the first side, and a first surface and a second surface provided on the opposite side of the first surface, The cross-sectional shape of the first light guide plate is a trapezoidal shape in which the lower side is longer than the upper side. The second light guide plate is provided on the first light guide plate, The second light guide plate has an integrally formed third light guide plate and a first protrusion, The cross-sectional shape of the third light guide plate is a trapezoidal shape in which the lower side is longer than the upper side. The third light guide plate has a third surface and a fourth surface provided on the opposite side of the third surface, and has a third side and a fourth side provided on the opposite side of the third side, The first protrusion has a second and a third protrusion that are integrally formed with it. The cross-sectional shape of the second protrusion is a trapezoid, where the upper side is longer than the lower side. The second convex portion has a fifth side parallel to the third side and a sixth side provided on the side opposite to the fifth side. The cross-sectional shape of the third convex portion is triangular. The third convex portion has a seventh side in contact with the second side and an eighth side different from the seventh side. The sixth side of the second convex portion and the eighth side of the third convex portion constitute a ninth side formed integrally. The light source element is provided facing the third side of the third light guide plate. The reflector is provided facing the first surface of the first light guide plate. The second surface of the first light guide plate and the third surface of the third light guide plate face each other. A plurality of fourth convex portions are provided in a first region of the first surface of the first light guide plate. The fourth side and the ninth side constitute a side in a "く" shape. 【Brief Description of Drawings】 【0008】 [Figure 1] FIG. 1 is a perspective view showing an example of the appearance of a display device according to an embodiment. [Figure 2] FIG. 2 is a perspective view showing a schematic configuration of a display device provided in a display device according to an embodiment. [Figure 3] FIG. 3 is a cross-sectional view showing a schematic configuration of the display device. [Figure 4] FIG. 4 is a cross-sectional view showing a schematic configuration of the display device. [Figure 5] FIG. 5 is a cross-sectional view showing an example of a more detailed configuration of the lighting device. [Figure 6] FIG. 6 is a cross-sectional view showing another configuration example of the lighting device in Embodiment 1. [Figure 7] FIG. 7 is a cross-sectional view showing an example of the lighting device in Embodiment 2. [Figure 8] FIG. 8 is a partially enlarged view of FIG. 7. [Figure 9] FIG. 9 is a cross-sectional view showing an example of a schematic configuration of the display device in Embodiment 2. [Figure 10]Figure 10 is a cross-sectional view showing an example of a display device in Embodiment 2. [Figure 11] Figure 11 is a cross-sectional view showing an example of a schematic configuration of the display device according to Embodiment 2. [Figure 12] Figure 12 is a cross-sectional view showing an example of a lighting device in Embodiment 3. [Figure 13] Figure 13 is a cross-sectional view showing an example of a schematic configuration of the display device according to Embodiment 3. [Figure 14] Figure 14 is a cross-sectional view showing an example of a display device in Embodiment 3. [Figure 15] Figure 15 is a cross-sectional view showing an example of a schematic configuration of the display device according to Embodiment 3. [Modes for carrying out the invention] 【0009】 The embodiments of the present invention will be described below with reference to the drawings. Note that the disclosure is merely an example, and modifications that can be easily conceived by those skilled in the art while maintaining the spirit of the invention are naturally included within the scope of the present invention. Furthermore, in order to clarify the explanation, the drawings may schematically represent the width, thickness, shape, etc., of each part compared to the actual embodiment, but these are merely examples and do not limit the interpretation of the present invention. In addition, in this specification and in each drawing, elements similar to those described above in previously shown drawings are denoted by the same reference numerals, and detailed explanations may be omitted as appropriate. 【0010】 The embodiments described herein are not general in nature, but rather embodiments that illustrate the same or corresponding specific technical features of the present invention. A display device according to one embodiment will be described in detail below with reference to the drawings. 【0011】 In this embodiment, the first direction X, the second direction Y, and the third direction Z are orthogonal to each other, but they may intersect at angles other than 90 degrees. The direction toward the tip of the arrow in the third direction Z is defined as up or upward, and the direction opposite to the direction toward the tip of the arrow in the third direction Z is defined as down or downward. The first direction X, the second direction Y, and the third direction Z may also be referred to as the X direction, the Y direction, and the Z direction, respectively. 【0012】 Furthermore, when referring to "the second member above the first member" and "the second member below the first member," the second member may be in contact with the first member or may be located away from the first member. In the latter case, a third member may be interposed between the first member and the second member. On the other hand, when referring to "the second member above the first member" and "the second member below the first member," the second member is in contact with the first member. 【0013】 Furthermore, assuming that there is an observation position for observing the display device on the tip side of the arrow in the third direction Z, viewing from this observation position toward the XY plane defined by the first direction X and the second direction Y is called a planar view. Viewing a cross-section of the display device in the XZ plane defined by the first direction X and the third direction Z, or in the YZ plane defined by the second direction Y and the third direction Z, is called a cross-sectional view. 【0014】 [Embodiment 1] Figure 1 is a perspective view showing an example of the appearance of a display device according to an embodiment. In this embodiment, the display device includes a head-mounted display (HMD) that is worn on the user's head. Such a display device is used to provide, for example, virtual reality (VR) to a user wearing the display device on their head. 【0015】 As shown in Figure 1, the display device DSP includes a display panel PNLh for the left eye and a display panel PNLm for the right eye. Display panels PNLh and PNLm are sometimes referred to as the first display panel and the second display panel, respectively. Display panels PNLh and PNLm are independent display panels. 【0016】 Display panel PNLh and display panel PNLm are positioned in front of the left and right eyes of the user USR when the user USR is wearing the display device DSP on their head. In this embodiment, display panel PNLh and display panel PNLm are liquid crystal display panels having a liquid crystal layer. 【0017】 Figure 2 is a perspective view showing a schematic configuration of the display device provided in the display device according to the embodiment. Here, the configuration of the display panel PNLh will be mainly described. 【0018】 The display panel PNLh shown in Figure 2 comprises a first substrate SUB1 and a second substrate SUB2 facing the first substrate SUB1. The display panel PNLh also has a display area DA for displaying images. Furthermore, the display panel PNLh includes, for example, a plurality of pixels PX arranged in a matrix within the display area DA. 【0019】 Furthermore, the display panel PNLh includes a drive IC chip IC1 that drives the display panel PNLh, and a flexible circuit board FPC1 that transmits control signals to the display panel PNLh. The flexible circuit board FPC1 is connected to a control module (host computer) that controls the operation of the display device DSP. 【0020】 In the example shown in Figure 2, the first substrate SUB1 and the second substrate SUB2 each have a longer side along the first direction X and a shorter side along the second direction Y. Both the first substrate SUB1 and the second substrate SUB2 have an octagonal shape in plan view. This shape can also be described as a rectangle with its corners cut off. The display panel PNLh also has an octagonal shape in plan view. 【0021】 However, the shape of the display panel PNLh is not limited to this, and it may have a polygonal shape. The shape of the display panel may be such that it does not come into contact with the nose of the user USR, as described later, and it may have a shape in which the corners close to the nose of the user USR are cut out. 【0022】 In the example shown in Figure 2, the shape of the display panel PNLh was described. The display panel PNLm has a shape that is symmetrical to the display panel PNLh with respect to the second direction Y. The configuration of the display panel PNLm is the same as that of the display panel PNLh, except that it is symmetrical with respect to the second direction Y. 【0023】 Below the display panel PNLh, an illumination device ILDh is provided. In the example shown in Figure 2, only the light guide plate LGh of the illumination device ILDh is shown. The light guide plate LGh has a rectangular shape that extends along the first direction X and the second direction Y. 【0024】 Figure 3 is a cross-sectional view showing the schematic configuration of a display device. The display device DSP shown in Figure 3 comprises an illumination device ILDh and a display panel PNLh. The illumination device ILDh comprises a reflector REFh, a light guide plate LGLh, a light guide plate LGUh, an optical sheet OPSh, and a light source element LS1h. The reflector REFh, light guide plate LGLh, light guide plate LGUh, and optical sheet OPSh are stacked in this order. 【0025】 The light guide plates LGLh and LGUh constitute the light guide plate LGh shown in Figure 2. A display panel PNLh is provided on the lighting device ILDh. 【0026】 In Figure 3, of the light guide plate LGUh, the left-hand side is designated as edge GVU1h and the right-hand side as edge GVU2h. Of the light guide plate LGLh, the left-hand side is designated as edge GVL1h and the right-hand side as edge DFL. In other words, edge DFL is located on the opposite side of edge GVL1h. 【0027】 The light guide plate LGLh has a trapezoidal cross-sectional shape, with the lower side being longer than the upper side. The left side of this trapezoidal shape, side GVL1h, extends along the third direction Z. The right side of this trapezoidal shape, side DFL, extends at an angle with respect to the third direction Z. 【0028】 The light guide plate LGUh has a light guide plate LGUAh and a protrusion LGUBh. The light guide plate LGUAh and the protrusion LGUBh are integrally formed and constitute the light guide plate LGUh. The light guide plate LGUAh has a trapezoidal cross-sectional shape in which the lower side is longer than the upper side. The left side of the trapezoidal shape, side GVU1h, extends along the third direction Z. The right side of the trapezoidal shape, side GVA2h, extends at an angle with respect to the third direction Z. In other words, side GVA2h is located on the opposite side of the plane of the paper from side GVU1h. In Embodiment 1, the third direction Z is also referred to as the thickness direction. 【0029】 The convex portion LGUBh has a trapezoidal cross-sectional shape, with its upper side longer than its lower side. The left side of the convex portion LGUBh, side DFU, extends at an angle with respect to the third direction Z. Side DFU is a diagonal line sloping downwards to the right. 【0030】 The right-hand side of the convex portion LGUBh, edge GVB2h, extends at an angle with respect to the third direction Z. Edge GVB2h is a downward-sloping diagonal line. In other words, edge GVB2h is located on the opposite side of the plane from edge DFU. 【0031】 The edges DFU of the convex portion LGUBh and DFL of the light guide plate LGLh are approximately parallel. The edges GVB2h of the convex portion LGUBh and GVA2h of the light guide plate LGUAh are integrally formed to constitute edge GVU2h. Edge GVU2h is a diagonal line sloping downwards to the right. 【0032】 The light source element LS1h is positioned opposite the edge GVU1h of the light guide plate LGUh. Light emitted from the light source element LS1h is incident on the edge GVU1h of the light guide plate LGUh. 【0033】 The light source element LS1h can use a laser light source (laser diode) such as a semiconductor laser that emits laser light. The laser light may be diffuse light with a spread centered on the irradiation direction, or it may be polarized laser light. 【0034】 Although edges GVU1h and GVL1h are referred to as edges, they are actually planes parallel to the YZ plane. Edges GVU2h, DFU, and DFL are actually planes inclined at an angle to the YZ plane. The angles of inclination of edge GVU2h, and the angles of inclination of edges DFU and DFL are different in Figure 3, but they may be the same. 【0035】 The main surfaces of the reflector REFh, light guide plate LGLh, light guide plate LGUh, and optical sheet OPSh are provided with multiple protrusions (also called prisms). 【0036】 Figure 4 is a cross-sectional view showing the schematic configuration of the display device. The display device DSP shown in Figure 4 comprises an illumination device ILDh for the left eye, a display panel PNLh for the left eye, an illumination device ILDm for the right eye, and a display panel PNLm for the right eye. The display panel PNLh is mounted on the illumination device ILDh. The display panel PNLm is mounted on the illumination device ILDm. 【0037】 The lighting device ILDh and display panel PNLh have the same configuration as the lighting device ILDh and display panel PNLh shown in Figure 3. The lighting device ILDm and display panel PNLm are positioned symmetrically to the lighting device ILDh and display panel PNLh with respect to the YZ plane. 【0038】 The ILDm lighting device comprises a reflector REFm, a light guide plate LGLm, a light guide plate LGUm, an optical sheet OPSm, and a light source element LS1m. The reflector REFm, light guide plate LGLm, light guide plate LGUm, and optical sheet OPSm are stacked in this order. 【0039】 The light guide plate LGUm has sides GVU1m and GVU2m. Side GVU1m is located on the right side of the paper and faces the light source element LS1m. Side GVU2m is located on the left side of the paper and faces side GVU2h of the light guide plate LGUh. 【0040】 The light guide plate LGLm has sides GVL1m and GVL2m. Side GVL1m is located on the right side of the paper and is positioned to coincide with side GVU1m of light guide plate LGUm along the third direction Z. Side GVL2m is located on the left side of the paper and is opposite side GVL2h of light guide plate LGLh. 【0041】 The cross-sectional shapes of the light guide plates LGLh and LGLm are trapezoidal, with the lower side being longer than the upper side. As described above, the light guide plate LGUh has a trapezoidal cross-sectional shape, a light guide plate LGUAh, and a trapezoidal convex portion LGUBh. The light guide plate LGUm, similar to the light guide plate LGUh, has a trapezoidal cross-sectional shape, a light guide plate LGUAm, and a trapezoidal convex portion LGUBm. 【0042】 Figure 5 is a cross-sectional view showing an example of a more detailed configuration of the lighting device. The lighting device ILDh shown in Figure 5 has, in addition to the configuration of the lighting device shown in Figure 3, a mirror, which is a reflective member, in contact with sides GVU2h and GVL2h. 【0043】 Of the main surfaces of the light guide plate LGUAh, the main surface facing the optical sheet OPSh is defined as surface UUS. The main surface opposite to surface UUS, which is the lower surface of the light guide plate LGUAh, is defined as surface UBS. The lower surface of the convex portion LGUBh is defined as surface UBSb. The upper surface of the convex portion LGUBh is defined as surface VLL. The left side of the convex portion LGUBh is defined as side DFU, as described above. In the region where the light guide plate LGUAh and the convex portion LGUBh are integrally formed, surfaces UBS and VLL are in contact. Alternatively, in the region where the light guide plate LGUAh and the convex portion LGUBh are integrally formed, surfaces UBS and VLL can be said to be the same. 【0044】 Let LUS be the main surface of light guide plate LGLh that is opposite surface UBS of light guide plate LGUAh. Let LBS be the main surface opposite surface LUS. Let DFL be the right-hand side of light guide plate LGLh, as described above. 【0045】 Multiple protrusions PR (also called prisms or grooves) are provided in a portion of area APRh on the surface LBS of the light guide plate LGLh. 【0046】 Let the thickness of the light guide plate LGLh (length along the third direction Z) be thickness d0. Let the thickness of the light guide plate LGUAh be thickness d1. 【0047】 The light LT emitted from the light source element LS1h includes a principal ray ML and diffuse light DL. The light LT emitted from the light source element LS1h is incident on the light guide plate LGUAh from edge GVU1h. The width dd of the diffuse light DL is the same as the thickness d1 of the light guide plate LGUAh. The light LT incident on the light guide plate LGUAh from edge GVU1h propagates along the first direction X. 【0048】 The light LT that reaches edge GVA2h is reflected downward by mirror MRRh. The reflected light LT then proceeds from light guide plate LGUAh on light guide plate LGUh to convex portion LGUBh. The light LT then exits from edge DFU on convex portion LGUBh and enters the interior of light guide plate LGLh from edge DFL on light guide plate LGLh. 【0049】 Light LT incident on the light guide plate LGLh propagates in the opposite direction to the first direction X, undergoing repeated total internal reflection between surfaces LBS and LUS within the light guide plate LGLh. During this time, the condition that the width dd of the diffuse light DL is equal to the thickness d1 (dd=d1) is maintained. 【0050】 When light LT propagating within the light guide plate LGLh in the opposite direction to the first direction X is incident on the convex portion PR, it is reflected by the convex portion PR and emitted upward. It is emitted from the surface LUS to the light guide plate LGUh, and further emitted from the surface UUS of the light guide plate LGUh to the optical sheet OPSh. The light LT emitted to the optical sheet OPSh is further emitted upward along the third direction Z by the convex portion provided on the optical sheet OPSh. 【0051】 When the principal ray ML of the light LT reflected by mirror MRRh enters the surface LBS of the light guide plate LGLh at an angle A0 of 26.5° (A0=26.5°), the light LT, including the diffuse ray DL, strikes the region APRh evenly. When the light strikes the region APRh evenly, all of the light LT is emitted upward. In other words, the extraction efficiency of the light LT increases. 【0052】 To satisfy the condition that angle A0 is 26.5° (A0 = 26.5°), it is preferable that the thickness d1 of the light guide plate LGUh is 1.8 times or more the thickness d0 of the light guide plate LGLh (d1 ≥ 1.8d0). However, the refractive index n of the light guide plates LGLh and LGUh should be 1.4 or more and 1.6 (1.4 ≤ n ≤ 1.6). Examples of such materials include transparent resin materials. 【0053】 Furthermore, under the above conditions, the angle between the surface LBS and the edge DFL of the light guide plate LGLh is also defined as angle A0. In this case, the angle A1 between the principal ray ML and the edge DFU is preferably 48° or greater (A1≧48°). For example, when angle A0 is 26.5° (A0=26.5°), angle A1 is 53° (A1=53°). If angle A1 is less than 48°, the light LT incident on the light guide plate LGLh undergoes repeated total internal reflection and propagates through the light guide plate LGLh without hitting the convex PR. If the light LT does not hit the convex PR, it is not emitted upward, and the extraction efficiency decreases. 【0054】 Furthermore, to satisfy the above conditions, the angle Ab between face UUS and edge GVU2h is preferably 76.75° (Ab = 76.75°). It should also be noted that angle Ab is the angle formed by the mirror MRRh with respect to the first direction X. 【0055】 According to this embodiment, it is possible to obtain a lighting device with increased light extraction efficiency. By equipping such a lighting device, it is possible to obtain a display device with improved brightness. 【0056】 <Configuration Example 1 of Embodiment 1> Figure 6 is a cross-sectional view showing another configuration example of the lighting device in Embodiment 1. The configuration example shown in Figure 6 differs from the configuration example shown in Figure 5 in that it has a mirror-finished support member. 【0057】 The lighting device ILDh shown in Figure 6 replaces the mirror MRRh in Figure 5 with a support member SPTh having a mirror-finished surface MRF as a reflective element. The support member SPTh may be made of a synthetic resin such as plastic. The mirror-finished surface MRF may be formed by vapor deposition of a metal such as aluminum. Configuration Example 1 also achieves the same effects as Embodiment 1. 【0058】 [Embodiment 2] Figure 7 is a cross-sectional view showing an example of a lighting device in Embodiment 2. The configuration example shown in Figure 7 differs from the configuration example shown in Figure 5 in that it performs total internal reflection at the edge of the light guide plate without using mirrors. 【0059】 Figure 8 is a magnified view of a portion of Figure 7. Figure 8 shows the principal ray ML and diffuse light DL between the light source element LS1h and the side GVU1h of the light guide plate LGUh. Of the light LT emitted from the light source element LS1h, the principal ray ML propagates along the first direction X. 【0060】 The diffusion angle dA represents the angle of inclination of the diffuse light DL relative to the principal ray ML. The diffuse light DL spreads clockwise and counterclockwise with a diffusion angle dA relative to the first direction X, which is the direction of extension of the principal ray ML. 【0061】 Returning to Figure 7, the lighting device ILDh will be described in more detail. The lighting device ILDh has a light guide plate LGh which has a roughly U-shape, or roughly the shape of the letter U turned on its side. The light guide plate LGh has a light guide plate LGUh and a light guide plate LGLh. The light guide plate LGUh has an integrally formed light guide plate LGUAh and a convex portion LGUBh. The convex portion LGUBh further has an integrally formed convex portion LGUCh and a convex portion LGUDh. 【0062】 The light guide plate LGLh shown in Figure 7 has the same configuration as the light guide plate LGLh shown in Figure 5. The explanation of the light guide plate LGLh shown in Figure 7 will be omitted, as it follows the explanation in Figure 5. 【0063】 The cross-sectional shape of the light guide plate LGUAh is a trapezoid with the bottom side longer than the top side. The cross-sectional shape of the convex part LGUCh is a trapezoid with the top side longer than the bottom side. The cross-sectional shape of the convex part LGUDh is triangular. The cross-sectional shape of the light guide plate LGLh is a trapezoid with the top side longer than the bottom side. 【0064】 The trapezoidal cross-sectional shape of the light guide plate LGUAh has, as described above, an upper side that is shorter than the lower side and a lower side that is longer than the upper side. The surface corresponding to the upper side is denoted as surface UUS, and the surface corresponding to the lower side is denoted as surface UBS. 【0065】 Let GVU1h be the left side of the trapezoidal cross-section of the light guide plate LGUAh. Let GVA2h be the right side of the trapezoidal cross-section of the light guide plate LGUAh. GVA2h extends at an angle with respect to the third direction Z. GVA2h is a sloping hypotenuse with respect to the plane of the paper. GVA2h is located on the opposite side of the plane of the paper from GVU1h. 【0066】 The trapezoidal cross-sectional shape of the convex portion LGUCh has, as described above, an upper side that is longer than the lower side and a lower side that is shorter than the upper side. The surface corresponding to the upper side is called surface CUS, and the surface corresponding to the lower side is called surface CBS. In the region where the light guide plate LGUAh and the convex portion LGUCh are integrally formed, surfaces UBS and CUS are in contact. Alternatively, in the region where the light guide plate LGUAh and the convex portion LGUCh are integrally formed, surfaces UBS and CUS can be said to be the same. 【0067】 Let GVC1h be the left side of the trapezoidal cross-section of the convex portion LGUCh. Side GVC1h extends along the third direction Z. It can also be said that side GVC1h is parallel to side GVU1h. Let GVC2h be the right side of the trapezoidal cross-section of the convex portion LGUCh. Side GVC2h extends at an angle to the third direction Z. 【0068】 The triangular cross-sectional shape of the convex portion LGUDh has three sides. One of these sides, surface DUS, is in contact with surface CBS. Alternatively, surface DUS and surface CBS can be considered the same. 【0069】 The edge DFU, which is one of the three edges of the convex portion LGUDh, extends at an angle with respect to the third direction Z. Edge DFU is approximately parallel to edge DFL of the light guide plate LGLh. 【0070】 GVD2h, another side of the three sides of the convex LGUDh, is integrally formed with GVC2h and constitutes GVB2h. Sides GVC2h, GVD2h, and GVB2h are sloping downwards to the left with respect to the plane of the paper. 【0071】 Edges GVA2h and GVB2h form a V-shaped edge. In other words, edges GVA2h and GVB2h form a shape that is like a mountain shape turned on its side. Alternatively, edges GVA2h and GVB2h can be said to form a shape similar to the inequality sign ">". 【0072】 Although the edge GVL1h of the light guide plate LGLh is called an edge, it is actually a plane parallel to the YZ plane. The edge DFL of the light guide plate LGLh is actually a plane that is inclined at an angle to the YZ plane. 【0073】 The edges GVU1h of the light guide plate LGUAh and GVC1h of the convex part LGUCh are referred to as edges, but are actually planes parallel to the YZ plane. The edge GVA2h of the light guide plate LGUAh is referred to as an edge, but is actually a plane that is inclined at an angle to the YZ plane. The edges GVC2h of the convex part LGUCh and GVD2h of the convex part LGUDh are referred to as edges, but are actually planes that are inclined at an angle to the YZ plane. The edge DFU of the convex part LGUDh is referred to as an edge, but is actually a plane that is inclined at an angle to the YZ plane. 【0074】 The integrally formed edges GVC2h and GVD2h, i.e., edge GVB2h, are referred to as edges, but are actually surfaces that are inclined at an angle with respect to the YZ plane. The surface referred to as edge GVA2h and the surface referred to as edge GVB2h are inclined with respect to the YZ plane at different angles. 【0075】 A space exists between the light guide plates LGUAh and LGLh, in the region where the protrusion LGUBh is not provided. The distance between the surface UBS of light guide plate LGUAh and the surface LUS of light guide plate LGLh in the region where the protrusion LGUBh is not provided (the region where the space exists) is defined as length dg. Details of length dg will be described later. 【0076】 The light LT emitted from the light source element LS1h includes a principal ray ML and diffuse light DL. The light LT emitted from the light source element LS1h is incident on the light guide plate LGUAh of the light guide plate LGUh from edge GVU1h. The width dd of the diffuse light DL is the same as the thickness d1 of the light guide plate LGUh. The light LT incident on the light guide plate LGUAh from edge GVU1h propagates along the first direction X. 【0077】 The light LT that reaches edge GVA2h undergoes total internal reflection downwards at edge GVA2h. The light LT that has undergone total internal reflection at edge GVA2h reaches edge GVB2h and undergoes total internal reflection at edge GVB2h. The light LT that has undergone total internal reflection at edge GVB2h exits the light guide plate LGUh from edge DFU. The light that exits from edge DFU enters the interior of the light guide plate LGLh from edge DFL of the light guide plate LGLh. 【0078】 Light LT incident inside the light guide plate LGLh undergoes further total internal reflection at the surface LBS of the light guide plate LGLh. The light that undergoes total internal reflection at the surface LBS propagates in the opposite direction to the first direction X while repeatedly undergoing total internal reflection between the surface LBS and the surface LUS within the light guide plate LGLh. At this time, the condition that the width dd of the diffuse light DL is the same as the thickness d1 (dd=d1) is maintained. 【0079】 When light LT propagating within the light guide plate LGLh in the opposite direction to the first direction X is incident on the convex portion PR, it is reflected by the convex portion PR and emitted upward. It is emitted from the surface LUS to the light guide plate LGUh, and then further emitted upward along the third direction Z from the surface UUS of the light guide plate LGUh. 【0080】 When the angle A0 of incidence on the surface LBS of the light guide plate LGLh is 26.5° (A0=26.5°), the light LT, including diffuse light DL, strikes the region APRh evenly. When the light strikes the region APRh evenly, all of the light LT is emitted upward. In other words, the extraction efficiency of the light LT increases. 【0081】 Angle A2 is defined as the angle at which the principal ray ML of the light LT, which has undergone total internal reflection at edge GVA2h, enters edge GVB2h. Angle A2 is preferably 48° or less (A2 ≤ 48°). If the light source element LS1h is a laser light source element and the diffusion angle dA of the diffuse light DL is 6.5°, then angle A2 is preferably 41.5° or less (A2 ≤ 41.5°). 【0082】 Furthermore, it is preferable that the angle Ab of the side GVA2h of the light guide plate LGUAh with respect to the first direction X (the angle between side GVA2h and face UUS) be 41.5° or less (Ab ≤ 41.5°). 【0083】 By setting angles A2 and Ab to the above conditions, optical LT undergoes total internal reflection at edges GVA2h, GVB2h, and plane LBS while maintaining the conditions for total internal reflection. 【0084】 Similar to Figure 5, in Figure 7, the angle A1 between the principal ray ML incident on the surface LBS and the edge is preferably 48° or greater (A1 ≥ 48°). For example, angle A1 is 53° (A1 = 53°). 【0085】 Let Aa be the angle of edge GVB2h with respect to the first direction X, or the angle formed by face LBS and edge GVB2h. For example, angle Aa can be 68° (Aa=68°). 【0086】 Let dg be the length between the surface UBS of light guide plate LGUAh and the surface LUS of light guide plate LGLh. The angle F, which is the total reflection angle, is given by F = cos -1 It is expressed as (1 / n) (where n is the refractive index). Since angles Ab and A2 are due to total internal reflection, they must be less than or equal to angle F. 【0087】 Let dA be the diffusion angle of the diffuse light DL. Considering the diffusion angle dA, for the diffuse light DL to satisfy the total internal reflection condition, it must be less than or equal to (F-dA). Here, A2 = π - Aa - 2Ab (Equation 1). π is 180° (π = 180°). 【0088】 Between angles Aa, Ab, and A0, the equation Aa + Ab = (A0 + π) / 2 (Equation 2) holds. 【0089】 The length dg is expressed by (Equation 3). 【number】 【0090】 As described above, using (Equation 3), an appropriate interval dg can be obtained based on angles Aa, A0, diffusion angle dA, length d0, and length d1. 【0091】 Figure 9 is a cross-sectional view showing an example of a schematic configuration of the display device of Embodiment 2. An optical sheet OPSh and a display panel PNLh are provided on the illumination device ILDh. 【0092】 The display device DSP, as shown in Figure 4, comprises an illumination device ILDh, an optical sheet OPSh, and a display panel PNLh, and an illumination device ILDm, an optical sheet OPSm, and a display panel PNLm arranged symmetrically with respect to the second direction Y. The reference numerals assigned to the components of illumination device ILDm are the same as those of the components of the corresponding illumination device ILDh, but with the "h" at the end replaced by "m". 【0093】 In Embodiment 2, it is also possible to efficiently extract the light LT emitted from the light source element LS1h. 【0094】 <Configuration Example 1 of Embodiment 2> Figure 10 is a cross-sectional view showing an example of a display device in Embodiment 2. The configuration example shown in Figure 10 differs from the configuration example shown in Figure 9 in that a display panel PNLh is provided between the light guide plate LGUh and the light guide plate LGLh. 【0095】 In the display device DSP shown in Figure 10, an optical sheet OPSh and a display panel PNLh are provided between the surface LUS of the light guide plate LGLh and the surface UBS of the light guide plate LGUAh. The optical sheet OPSh and the display panel PNLh are arranged superimposed on the region APRh of the light guide plate LGLh, where multiple protrusions PR are provided. The length dg between the surface LUS and the surface UBS is given by (Equation 3) as described above. If the sum of the thickness of the optical sheet OPSh and the thickness of the display panel PNLh is less than the length dg, then it is possible to provide the thickness of the optical sheet OPSh and the display panel PNLh between the surface LUS of the light guide plate LGLh and the surface UBS of the light guide plate LGUh. 【0096】 Figure 11 is a cross-sectional view showing an example of a schematic configuration of the display device of Embodiment 2. The display device DSP, as in Figures 4 and 9, comprises an illumination device ILDh, an optical sheet OPSh, and a display panel PNLh, and an illumination device ILDm, an optical sheet OPSm, and a display panel PNLm arranged symmetrically with respect to the second direction Y. The reference numerals assigned to the components of illumination device ILDm are the same as those of the components of the corresponding illumination device ILDh, but with the "h" at the end replaced by "m". 【0097】 By placing the optical sheet OPSh and display panel PNLh between the light guide plates LGUh and LGLh, and the optical sheet OPSm and display panel PNLm between the light guide plates LGUm and LGLm, the thickness of the display device DSP can be reduced. Configuration Example 1 also achieves the same effects as Embodiment 2. 【0098】 [Embodiment 3] Figure 12 is a cross-sectional view showing an example of a lighting device in Embodiment 2. The configuration example shown in Figure 12 differs from the configuration example shown in Figure 7 in that the lighting device has a single, integrally formed light guide plate. 【0099】 The lighting device ILDh shown in Figure 12 has a light guide plate LGh which has a roughly U-shape or a roughly horizontal U-shape. The light guide plate LGh has an integrally formed light guide plate LGUh and a light guide plate LGLh. The light guide plate LGUh has an integrally formed light guide plate LGUAh and a convex portion LGUBh. The convex portion LGUBh has an integrally formed convex portion LGUCh and a convex portion LGUDh. 【0100】 The cross-sectional shape of the light guide plate LGh shown in Figure 12 differs from that of the light guide plate LGh shown in Figure 7 in that the light guide plate LGUh (light guide plate LGUAh and protrusion LGUBh) and the light guide plate LGLh are integrally formed. The edge DFU of the protrusion LGUDh of the light guide plate LGUh and the edge DFL of the light guide plate LGLh shown in Figure 12 are in contact with each other. Alternatively, it can be said that the edges DFU and DFL are the same. 【0101】 The shapes of the light guide plate LGUAh, the protrusion LGUCh, and the protrusion LGUDh shown in Figure 12 are the same as those in Figure 7. In the light guide plate LGh shown in Figure 12, as described above, the light guide plate LGUAh, the protrusion LGUCh, the protrusion LGUDh, and the light guide plate LGLh are integrally formed. 【0102】 Similar to Figure 7, the hypotenuse of the convex LGUCh, side GVC2h, is integrated with side GVD2h of the convex LGUch to form a single side GVB2h. Side GVB2h is a hypotenuse that slopes downward to the left with respect to the plane of the paper. 【0103】 Edges GVA2h and GVB2h form a V-shaped edge. In other words, edges GVA2h and GVB2h form a shape that is like a mountain shape turned on its side. Alternatively, edges GVA2h and GVB2h can be said to form a shape similar to the inequality sign ">". 【0104】 A space exists between the light guide plates LGUAh and LGLh, in the region where the protrusion LGUBh is not provided. The length dg, which is the distance between the surface UBS of the light guide plate LGUh and the surface LUS of the light guide plate LGLh in the region where the protrusion LGUBh is not provided (the region where the space exists), satisfies (Equation 3) described in Embodiment 2. 【0105】 The propagation of light LT emitted from the light source element LS1h within the light guide plate LGh is substantially the same as in Embodiment 2. However, in Embodiment 2, the light LT is emitted from the edge DFU of the protrusion LGUDh of the light guide plate LGUh. The emitted light LT is then incident into the interior of the light guide plate LGLh from the edge DFL of the light guide plate LGLh. That is, in Embodiment 2, the light LT is first emitted outside the light guide plate LGUh and the light guide plate LGLh. On the other hand, in Embodiment 3, the light guide plate LGh is integrally formed. The light LT that propagates from the edge DFU of the protrusion LGUDh to the edge DFL of the light guide plate LGLh propagates within the interior of the light guide plate LGh. Therefore, in Embodiment 3, the light LT can be propagated more efficiently, and the light LT can be extracted more efficiently. 【0106】 Figure 13 is a cross-sectional view showing an example of a schematic configuration of the display device of Embodiment 3. An optical sheet OPSh and a display panel PNLh are provided on the illumination device ILDh. 【0107】 The display device DSP, as in Figures 4 and 9, comprises an illumination device ILDh, an optical sheet OPSh, and a display panel PNLh, and an illumination device ILDm, an optical sheet OPSm, and a display panel PNLm arranged symmetrically with respect to the second direction Y. The reference numerals assigned to the components of illumination device ILDm are the same as those of the components of the corresponding illumination device ILDh, but with the "h" at the end replaced by "m". 【0108】 In Embodiment 3, it is also possible to efficiently extract the light LT emitted from the light source element LS1h. 【0109】 <Configuration Example 1 of Embodiment 3> Figure 14 is a cross-sectional view showing an example of a display device in Embodiment 3. The configuration example shown in Figure 14 differs from the configuration example shown in Figure 12 in that a display panel PNLh is provided between the light guide plate LGUh and the light guide plate LGLh. 【0110】 In the display device DSP shown in Figure 14, an optical sheet OPSh and a display panel PNLh are provided between the surface LUS of the light guide plate LGLh and the surface UBS of the light guide plate LGUh. The optical sheet OPSh and the display panel PNLh are arranged superimposed on region APRh of the light guide plate LGLh, where multiple protrusions PR are provided. The length dg between the surface LUS and the surface UBS is given by (Equation 3) as described above. If the sum of the thickness of the optical sheet OPSh and the thickness of the display panel PNLh is less than the length dg, it is possible to provide the thickness of the optical sheet OPSh and the display panel PNLh between the surface LUS of the light guide plate LGLh and the surface UBS of the light guide plate LGUh. 【0111】 Figure 15 is a cross-sectional view showing an example of a schematic configuration of the display device of Embodiment 2. The display device DSP, as in Figure 4, includes an illumination device ILDh, an optical sheet OPSh, and a display panel PNLh, and an illumination device ILDm, an optical sheet OPSm, and a display panel PNLm arranged symmetrically with respect to the second direction Y. The reference numerals assigned to the components of illumination device ILDm are the same as those of the components of the corresponding illumination device ILDh, but with the "h" at the end replaced by "m". 【0112】 By placing the optical sheet OPSh and display panel PNLh between the light guide plates LGUh and LGLh, and the optical sheet OPSm and display panel PNLm between the light guide plates LGUm and LGLm, the thickness of the display device DSP can be reduced. Configuration Example 1 also achieves the same effects as Embodiment 2. 【0113】 In this disclosure, it is possible to obtain an illumination device with increased light extraction efficiency. Furthermore, by incorporating such an illumination device, it is possible to obtain a display device with improved brightness. 【0114】 In this disclosure, light guide plates LGLh and LGUh are also referred to as the first light guide plate and the second light guide plate. Light guide plate LGUAh of light guide plate LGUh is also referred to as the third light guide plate. 【0115】 In this disclosure, surfaces LBS and LUS of the light guide plate LGLh are also referred to as the first surface and the second surface, respectively. Surfaces UBS and UUS of the light guide plate LGUAh are also referred to as the third surface and the fourth surface, respectively. The thickness d0 of the light guide plate LGLh is also referred to as the first thickness, and the thickness d1 of the light guide plate LGUAh is also referred to as the second thickness. In this disclosure, the third direction Z is also referred to as the thickness direction. 【0116】 In this disclosure, the region APRh of the surface LBS of the light guide plate LGLh, in which multiple protrusions PR are provided, is also referred to as the first region. 【0117】 In Figure 5, the edges GVL1h and DFL of the light guide plate LGLh are also referred to as the first and second edges, respectively. The edges GVU1h and GVA2h of the light guide plate LGUAh are also referred to as the third and fourth edges, respectively. The edge DFU of the protrusion LGUBh is also referred to as the fifth edge, and the edge GVB2h is also referred to as the sixth edge. The integrally formed edge GVA2h of the light guide plate LGUAh and the edge GVB2h of the protrusion LGUBh, which is edge GVU2h, are also referred to as the seventh edge. 【0118】 In Figure 5, when the principal ray ML of light LT reflected by mirror MRRh is incident on the surface LBS of light guide plate LGLh, the angle A0 formed by the principal ray ML and surface LBS is also called the first angle. 【0119】 In Figure 5, convex LGUBh is referred to as the first convex part, and convex PR is referred to as the second convex part. 【0120】 In Figure 7, convex LGUBh is called the first convex part. Convex LGUCh is called the second convex part, and convex LGUDh is called the third convex part. Convex PR is called the fourth convex part. 【0121】 In Figure 7, the surfaces CUS and CBS of the convex LGUCh are also referred to as the fifth and sixth surfaces, respectively. 【0122】 In Figure 7, the edges GVL1h and DFL of the light guide plate LGLh are also referred to as the first and second edges, respectively. The edges GVU1h and GVA2h of the light guide plate LGUAh are also referred to as the third and fourth edges, respectively. The edges DFU and GVC2h of the convex portion LGUCh are also referred to as the fifth and sixth edges, respectively. The edges DFU and GVD2h of the convex portion LGUDh are also referred to as the seventh and eighth edges, respectively. The edge GVB2h, which is integrally formed with the edges GVC2h of the convex portion LGUCh and GVD2h of the convex portion LGUDh, is also referred to as the ninth edge. 【0123】 In Figure 7, when the principal ray ML of light LT reflected by mirror MRRh is incident on the surface LBS of light guide plate LGLh, the angle A0 between the principal ray ML and surface LBS is also called the first angle. 【0124】 In Figure 12, the ordinal numbers of the light guide plate, protrusions, faces, edges, and angles are the same as in Figure 7. 【0125】 While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols] 【0126】 A0...angle, A1...angle, A2...angle, Aa...angle, Ab...angle, DL...diffuse light, GVL1h...side, GVL2h...side, GVU1h...side, GVU2h...side, ILDh...lighting device, LGBh...protrusion, LGLh...light guide plate, LGUh...light guide plate, LGh...light guide plate, LS1h...light source element, LT...light, ML...main ray, PNLh...display panel, PR...protrusion, dA...diffuse angle, dd...width, dg...interval.

Claims

[Claim 1] A first light guide plate having a first side and a second side provided on the opposite side of the first side, and a first surface and a second surface provided on the opposite side of the first surface, A second light guide plate is provided on the first light guide plate, A light source element is provided opposite the second light guide plate, A reflector is provided opposite the first surface of the first light guide plate, An optical sheet provided on the second light guide plate, Equipped with, The cross-sectional shape of the first light guide plate is a trapezoidal shape in which the lower side is longer than the upper side. The second light guide plate comprises an integrally formed third light guide plate and a first protrusion, The cross-sectional shape of the third light guide plate is a trapezoidal shape in which the lower side is longer than the upper side. The cross-sectional shape of the first protrusion is a trapezoidal shape in which the upper side is longer than the lower side. The third light guide plate has a third side and a fourth side provided on the opposite side of the third side, and a third surface and a fourth surface provided on the opposite side of the third surface. The first protrusion has a fifth side parallel to the second side and a sixth side provided on the opposite side of the fifth side. The second surface of the first light guide plate and the third surface of the third light guide plate face each other. Multiple second protrusions are provided in the first region of the first surface of the first light guide plate. The fourth side of the second light guide plate and the sixth side of the first protrusion form a seventh side that is integrally formed. The seventh side is inclined with respect to the thickness direction, A lighting device in which a reflective member is provided in contact with the seventh side. [Claim 2] The light emitted from the aforementioned light source element includes a principal ray and diffuse light. The light emitted from the light source element is incident on the third side of the third light guide plate. The light incident on the third side is reflected downward by the reflective member in contact with the seventh side. The light reflected by the reflective member exits from the fifth side of the first protrusion and enters the first light guide plate from the second side of the first light guide plate. The light incident on the second edge is reflected by the first surface. The light reflected by the first surface is reflected by the second surface, The light incident on the plurality of second protrusions provided in the first region of the first surface is emitted upward by the plurality of second protrusions. The lighting device according to claim 1, wherein the principal ray of the light incident on the first surface of the first light guide plate and the first angle it makes with the first surface are 26.5°. [Claim 3] The thickness of the first light guide plate is defined as the first thickness, and the thickness of the third light guide plate is defined as the second thickness. The lighting device according to claim 1, wherein the second thickness is 1.8 times or more the first thickness. [Claim 4] The lighting device according to claim 1, wherein the reflective member is a mirror. [Claim 5] The lighting device according to claim 1, wherein the reflective member is a support member with a mirror finish. [Claim 6] The lighting device according to claim 1, A display panel is provided on the aforementioned lighting device, A display device equipped with the following features. [Claim 7] A first light guide plate having a first side and a second side provided on the opposite side of the first side, and a first surface and a second surface provided on the opposite side of the first surface, A second light guide plate is provided on the first light guide plate, A light source element is provided opposite the second light guide plate, A reflector is provided opposite the first surface of the first light guide plate, Equipped with, The cross-sectional shape of the first light guide plate is a trapezoidal shape in which the lower side is longer than the upper side. The second light guide plate has an integrally formed third light guide plate and a first protrusion, The cross-sectional shape of the third light guide plate is a trapezoidal shape in which the lower side is longer than the upper side. The third light guide plate has a third surface and a fourth surface provided on the opposite side of the third surface, and has a third side and a fourth side provided on the opposite side of the third side, The first protrusion has a second and a third protrusion that are integrally formed with it. The cross-sectional shape of the second protrusion is a trapezoidal shape in which the upper side is longer than the lower side. The second protrusion has a fifth side parallel to the third side and a sixth side provided on the opposite side of the fifth side. The cross-sectional shape of the third protrusion is triangular, The third protrusion has a seventh side parallel to the second side and an eighth side separate from the seventh side. The sixth side of the second protrusion and the eighth side of the third protrusion form a ninth side that is integrally formed. The light source element is provided opposite the third side of the third light guide plate, The second surface of the first light guide plate and the third surface of the third light guide plate face each other. Multiple fourth protrusions are provided in the first region of the first surface of the first light guide plate. The fourth and ninth sides of the lighting device form a V-shaped side. [Claim 8] The light emitted from the aforementioned light source element includes a principal ray and diffuse light. The light emitted from the light source element is incident on the third side of the third light guide plate. The light incident on the third side is totally reflected downwards by the fourth side. The light that was totally reflected downward at the fourth edge is totally reflected downward at the ninth edge, The light that is totally reflected downward at the ninth edge exits from the seventh edge of the first protrusion and enters the first light guide plate from the second edge of the first light guide plate. The light incident on the second edge is reflected by the first surface. The light incident on the first surface is reflected by the first surface, The light reflected by the first surface is reflected by the second surface, The light incident on the plurality of fourth protrusions provided in the first region of the first surface is emitted upward by the plurality of fourth protrusions. The lighting device according to claim 7, wherein the principal ray of the light incident on the first surface of the first light guide plate and the first angle it makes with the first surface are 26.5°. [Claim 9] The thickness of the first light guide plate is defined as the first thickness, and the thickness of the third light guide plate is defined as the second thickness. The lighting device according to claim 7, wherein the second thickness is 1.8 times or more the first thickness. [Claim 10] The lighting device according to claim 7, An optical sheet provided on the aforementioned lighting device, A display panel provided on the optical sheet, A display device equipped with the following features. [Claim 11] The lighting device according to claim 7, An optical sheet is positioned between the first light guide plate and the third light guide plate, superimposed on the first region, A display panel is located between the first light guide plate and the third light guide plate, and is arranged superimposed on the first region. Equipped with, The display panel is a display device provided between the optical sheet and the third light guide plate. [Claim 12] A light guide plate having a first light guide plate and a second light guide plate formed integrally, A light source element is provided opposite the second light guide plate, A reflector is provided opposite the first light guide plate, Equipped with, The first light guide plate has a first side and a second side provided on the opposite side of the first side, and a first surface and a second surface provided on the opposite side of the first surface. The cross-sectional shape of the first light guide plate is a trapezoidal shape in which the lower side is longer than the upper side. The second light guide plate is provided on the first light guide plate, The second light guide plate has an integrally formed third light guide plate and a first protrusion, The cross-sectional shape of the third light guide plate is a trapezoidal shape in which the lower side is longer than the upper side. The third light guide plate has a third surface and a fourth surface provided on the opposite side of the third surface, and has a third side and a fourth side provided on the opposite side of the third side, The first protrusion has a second and a third protrusion that are integrally formed with it. The cross-sectional shape of the second protrusion is a trapezoidal shape in which the upper side is longer than the lower side. The second protrusion has a fifth side parallel to the third side and a sixth side provided on the opposite side of the fifth side. The cross-sectional shape of the third protrusion is triangular, The third protrusion has a seventh side that is in contact with the second side and an eighth side that is separate from the seventh side. The sixth side of the second protrusion and the eighth side of the third protrusion form a ninth side that is integrally formed. The light source element is provided opposite the third side of the third light guide plate, The reflector is provided facing the first surface of the first light guide plate, The second surface of the first light guide plate and the third surface of the third light guide plate face each other. Multiple fourth protrusions are provided in the first region of the first surface of the first light guide plate. The fourth and ninth sides of the lighting device form a V-shaped side. [Claim 13] The light emitted from the aforementioned light source element includes a principal ray and diffuse light. The light emitted from the light source element is incident on the third side of the third light guide plate. The light incident on the third side is totally reflected downwards by the fourth side. The light that was totally reflected downward at the fourth edge is totally reflected downward at the ninth edge, The light that is totally reflected downward at the ninth edge propagates from the seventh edge of the first protrusion to the second edge of the first light guide plate. The light incident on the second edge is reflected by the first surface. The light incident on the first surface is reflected by the first surface, The light reflected by the first surface is reflected by the second surface, The light incident on the plurality of fourth protrusions provided in the first region of the first surface is emitted upward by the plurality of fourth protrusions. The lighting device according to claim 12, wherein the principal ray of the light incident on the first surface of the first light guide plate and the first angle it makes with the first surface are 26.5°. [Claim 14] The thickness of the first light guide plate is defined as the first thickness, and the thickness of the third light guide plate is defined as the second thickness. The lighting device according to claim 12, wherein the second thickness is 1.8 times or more the first thickness. [Claim 15] The lighting device according to claim 12, An optical sheet provided on the aforementioned lighting device, A display panel provided on the optical sheet, A display device equipped with the following features. [Claim 16] The lighting device according to claim 12, An optical sheet is positioned between the first light guide plate and the third light guide plate, superimposed on the first region, A display panel is located between the first light guide plate and the third light guide plate, and is arranged superimposed on the first region. Equipped with, The display panel is a display device provided between the optical sheet and the third light guide plate.

Images