Liquid crystal module and head-mounted display

Abstract

To provide a liquid crystal module that can deliver uniformity between the front luminance and the luminance in the periphery field of view by means of a simple structure and also to provide a head-mounted display using such a liquid crystal module.SOLUTION: A liquid crystal module comprises: a lens unit including at least a first lens; a liquid crystal panel; and a backlight unit, which are provided in a stated order, wherein the backlight unit includes: a light-guide plate; and a first light source opposite a first side face of the light-guide plate, and the light-guide plate has: the first side face; and a light-exiting face that emits light, which is incident from the first side face, toward the liquid crystal panel, the light-guide plate further having a curved face portion in a cross-section in a first direction that is perpendicular to the first side face and the light-exiting face.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The following disclosure relates to a liquid crystal module and a head mounted display using the liquid crystal module. [Background technology]

[0002] In order to view content compatible with VR (Virtual Reality) technology and AR (Augmented Reality) technology, goggle-shaped displays that can be worn on the head are used. Displays of this type are generally called head-mounted displays (HMDs). In recent years, development of liquid crystal display devices used in HMDs has progressed. Examples of the HMD include a display panel such as a liquid crystal panel and a backlight on the rear side of the display panel.

[0003] For example, Patent Document 1 discloses a display device having a display panel including a plurality of light-emitting elements, each of which includes a light-emitting section and a light-emitting direction control member through which light emitted from the light-emitting section passes, in which the light-emitting direction control member in each light-emitting element is composed of a first region and a second region surrounding the first region, and the refractive index value n1 of the material constituting the first region is different from the refractive index value n2 of the material constituting the second region, and discloses a display device having an organic EL direct backlight. Patent Document 1 discusses controlling the emission direction of an image from a display device by arranging a color filter on light-emitting elements such as organic electroluminescence elements (OLED: Electroluminescence Diode) and light-emitting diodes (LED, Light Emitting Diode) arranged in a matrix, and further arranging a light-emitting direction control member on the color filter. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2021 / 149470 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, the adoption of folded optical lens systems has been increasing in order to reduce the set size of HMDs. On the other hand, conventional backlights used in smartphones and other devices are designed to provide uniform frontal luminance, assuming that the device will be viewed from the front. Therefore, when a conventional backlight is incorporated into an HMD using a folded optical lens system, the peripheral visual field of the HMD may experience a decrease in luminance because the viewing angle becomes narrower as light entering from an oblique direction is refracted by the HMD lens.

[0006] The present invention has been made in consideration of the above-mentioned current situation, and aims to provide a liquid crystal module that has a simple configuration and can achieve uniformity in frontal luminance and peripheral visual field luminance, and a head-mounted display that uses such a liquid crystal module. [Means for solving the problem]

[0007] (1) One embodiment of the present invention is a liquid crystal module comprising, in that order, a lens unit including at least a first lens, a liquid crystal panel, and a backlight unit, the backlight unit having a light guide plate and a first light source arranged opposite a first side surface of the light guide plate, the light guide plate having the first side surface and an exit surface that outputs light incident from the first side surface to the liquid crystal panel, and having a curved portion in a cross section in a first direction perpendicular to the first side surface and the exit surface.

[0008] (2) Furthermore, one embodiment of the present invention is a liquid crystal module, in addition to the configuration of (1) above, wherein the curved portion includes a first curved portion arranged between the first side surface and the exit surface in a cross section in the first direction.

[0009] (3) Furthermore, in one embodiment of the present invention, in addition to the configuration of (2) above, the light guide plate has a second side surface opposite the first side surface in the first direction, the backlight unit has a second light source arranged opposite the second side surface of the light guide plate, and the curved surface portion includes a second curved surface portion arranged between the second side surface and the exit surface in a cross section in the first direction.

[0010] (4) Moreover, an embodiment of the present invention is a liquid crystal module having the configuration of (2) or (3) above, wherein the radius of curvature of the first curved surface portion is different from the radius of curvature of the second curved surface portion.

[0011] (5) Furthermore, in one embodiment of the present invention, in addition to any one of the configurations (2) to (4) above, the light guide plate further has a third side and a fourth side facing each other in a second direction perpendicular to the first direction, and the curved surface portion includes, in a cross section in the second direction, a third curved surface portion arranged between the third side and the exit surface, and a fourth curved surface portion arranged between the fourth side and the exit surface.

[0012] (6) Furthermore, in one embodiment of the present invention, in addition to the configuration of (1) above, the curved surface portion is disposed in the center of the exit surface and curves toward the opposite side to the liquid crystal panel.

[0013] (7) Furthermore, one embodiment of the present invention is a liquid crystal module having any one of the configurations (1) to (6) above, wherein the light guide plate has a plurality of linear portions extending in the first direction on the exit surface, and has a plurality of recesses recessed toward the exit surface on a back surface opposite the exit surface.

[0014] (8) Furthermore, in accordance with an embodiment of the present invention, in addition to any one of the configurations (1) to (7) above, the lens unit further includes a second lens disposed between the first lens and the liquid crystal panel, the first lens and the second lens each have a semi-transmissive film on the liquid crystal panel side;

[0015] (9) Another embodiment of the present invention is a head mounted display comprising a liquid crystal module for a right eye, the liquid crystal module being described in any one of (1) to (8) above, and a liquid crystal module for a left eye, the liquid crystal module being described in any one of (1) to (8) above. Effect of the Invention

[0016] According to the present invention, it is possible to provide a liquid crystal module that can obtain uniformity in the front luminance and the luminance in the peripheral field of view with a simple configuration, and a head mounted display that uses the liquid crystal module. [Brief description of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view showing an example of a liquid crystal module according to a first embodiment of the present invention. [Figure 2A] FIG. 1 is a perspective view showing an example of a light guide plate used in embodiment 1. [Figure 2B] 2B is a schematic plan view of the light guide plate shown in FIG. 2A as viewed from the light output surface side. [Figure 2C] 2B is a schematic plan view of the light guide plate shown in FIG. 2A as viewed from the rear side. [Figure 2D] 2B is a schematic cross-sectional view of the light guide plate shown in FIG. 2A in a first direction D1. [Figure 2E] 2B is a schematic cross-sectional view of the light guide plate shown in FIG. 2A in a second direction D2. [Diagram 3] 1 is a schematic plan view of a light guide plate having a plurality of recesses and a plurality of linear portions and a light source, as viewed from the light output surface side. [Figure 4] 1 is a schematic plan view of a light guide plate having a plurality of recesses and a plurality of linear portions and a light source, as viewed from the light output surface side. [Diagram 5] FIG. 5 is a schematic cross-sectional view taken along line X1-X2 in FIGS. 3 and 4. [Figure 6] FIG. 5 is a schematic cross-sectional view taken along line X3-X4 in FIGS. 3 and 4. [Figure 7] 2 is a schematic plan view illustrating an example of the planar shape of a light guide plate. FIG. [Figure 8]2 is a schematic cross-sectional view illustrating a display method of the liquid crystal module shown in FIG. [Figure 9A] FIG. 11 is a perspective view showing an example of a light guide plate used in embodiment 2. [Figure 9B] 9B is a schematic plan view of the light guide plate shown in FIG. 9A as viewed from the light output surface side. [Figure 9C] 9B is a schematic cross-sectional view of the light guide plate shown in FIG. 9A in a first direction D1. [Figure 9D] 9B is a cross-sectional schematic diagram of the light guide plate shown in FIG. 9A in a second direction D2. [Figure 10] 11 is a cross-sectional view showing an example of a liquid crystal module according to a third embodiment. FIG. [Figure 11A] FIG. 11 is a perspective view showing an example of a light guide plate used in embodiment 3. [Figure 11B] 11B is a schematic plan view of the light guide plate shown in FIG. 11A as viewed from the light output surface side. [Figure 11C] 11B is a schematic cross-sectional view of the light guide plate shown in FIG. 11A in a first direction D1. [Figure 12] 11 is a cross-sectional view illustrating a head mounted display using the liquid crystal module of embodiment 3. FIG. [Figure 13] FIG. 11 is a cross-sectional view showing an example of a liquid crystal module according to a fourth embodiment. [Figure 14A] FIG. 13 is a perspective view showing an example of a light guide plate used in embodiment 4. [Figure 14B] 14B is a schematic plan view of the light guide plate shown in FIG. 14A as viewed from the light output surface side. [Figure 14C] 14B is a cross-sectional schematic diagram of the light guide plate shown in FIG. 14A in a first direction D1. [Figure 14D] 14B is a cross-sectional schematic diagram of the light guide plate shown in FIG. 14A in a second direction D2. [Figure 15] 1 is a schematic plan view of a light guide plate having a plurality of recesses and a plurality of linear portions and a light source, as viewed from the light output surface side. [Figure 16] 1 is a schematic plan view of a light guide plate having a plurality of recesses and a plurality of linear portions and a light source as viewed from the rear side. FIG. [Figure 17] 17 is a schematic cross-sectional view taken along line X5-X6 in FIG. 15 and FIG. 16. [Figure 18] 17 is a schematic cross-sectional view taken along line X7-X8 in FIG. 15 and FIG. 16. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described. The present invention is not limited to the contents described in the following embodiment, and appropriate design changes can be made within the scope of the configuration of the present invention. In the following description, the same reference numerals are appropriately used in common between different drawings for the same parts or parts having similar functions, and repeated explanations thereof will be omitted as appropriate. Each aspect of the present invention may be appropriately combined within the scope of the gist of the present invention.

[0019] <Embodiment 1> Fig. 1 is a cross-sectional view showing an example of a liquid crystal module according to the first embodiment. Fig. 1 is also a horizontal cross-sectional view showing the liquid crystal module in use. As shown in Fig. 1, the liquid crystal module 1 according to the first embodiment includes a lens unit 100, a liquid crystal panel 200, and a backlight unit 300, in this order. The lens unit 100 and the liquid crystal panel 200 are disposed to face each other with a gap therebetween. The liquid crystal panel 200 and the backlight unit 300 may be bonded and fixed by a fixing double-sided tape 401 or the like.

[0020] (Lens unit) Lens unit 100 includes at least a first lens 101. Lens unit 100 may be configured to form an image emitted from liquid crystal panel 200 on the retina of a user so that the user can recognize the image.

[0021] 1, the lens unit 100 may further include a second lens 102 disposed between the first lens 101 and the liquid crystal panel 200. Examples of the first lens 101 and the second lens 102 include a biconvex lens, a plano-convex lens, a convex meniscus lens, a biconcave lens, a plano-concave lens, a concave meniscus lens, an aspheric lens, a free-form lens, a Fresnel lens, a gradient index lens, and the like. The number of lenses included in the lens unit 100 is not particularly limited, and other lenses may be further included.

[0022] A preferable combination of the first lens 101 and the second lens 102 in the first embodiment is a convex meniscus lens and a convex meniscus lens, or the like.

[0023] The first lens 101 and the second lens 102 preferably have semi-transmissive films 101a and 102a, respectively, on the liquid crystal panel 200 side. The semi-transmissive films are also called half mirrors, and have the function of transmitting a part of the light incident from the liquid crystal panel 200 side and reflecting the other part towards the liquid crystal panel 200 side.

[0024] The semi-transparent film may be formed on the surface of a lens. Alternatively, a member having a semi-transparent film formed on the surface of a transparent substrate may be disposed separately from the lens. The semi-transparent film may be a metal thin film, which may be obtained by, for example, metal deposition or sputtering of silver, aluminum, or an alloy thereof.

[0025] 1 illustrates an example in which the lens unit 100 includes two lenses, but the lens unit 100 may include only the first lens 101. When the lens unit 100 includes only the first lens 101, the first lens 101 may be a Fresnel lens or the like.

[0026] (Liquid crystal panel) The liquid crystal panel 200 is a display panel that displays a desired image, and is a transmissive liquid crystal panel that transmits light emitted from the backlight unit 300 to the user side.

[0027] The liquid crystal panel 200 may include a liquid crystal panel having a pair of substrates and a liquid crystal layer held between the substrates. For example, a liquid crystal layer 203 may be sandwiched between a TFT substrate 201 and a color filter substrate 202, and the liquid crystal layer 203 may be sealed with a sealant 204. At least one of the pair of substrates is provided with electrodes for applying a voltage to the liquid crystal layer, and a display driver integrated circuit (DDIC: Display Driver IC) 205 is mounted on the TFT substrate 201. The display driver integrated circuit 205 is electrically connected to a liquid crystal panel driving flexible printed circuit board (FPC) 206, and an electric signal for driving the liquid crystal panel 200 is input from the flexible printed circuit board 206 to the display driver integrated circuit 205, and the display driver integrated circuit 205 controls the application of a voltage to the electrodes. When a voltage is applied to the liquid crystal layer, the orientation of the liquid crystal molecules in the liquid crystal layer changes, and light incident on the liquid crystal panel 200 is controlled.

[0028] The liquid crystal panel 200 may have a polarizing plate on each of the lens unit 100 side and the backlight unit 300 side.

[0029] (Backlight unit) The backlight unit 300 is a device that emits light toward the liquid crystal panel 200. As shown in FIG. 1, the backlight unit 300 has a light guide plate 310 and a light source 301 arranged to face a side surface of the light guide plate 310. The backlight unit 300 may also have a reflective sheet 302 arranged on the rear surface side of the light guide plate 310 and an optical sheet 303 arranged on the front surface side (liquid crystal panel 200 side) of the light guide plate 310. The light source 301 may be mounted on, for example, a flexible printed circuit board (FPC) 304 for mounting a light source. These members are stored in a housing 305.

[0030] The light source 301 may be, for example, a light emitting diode (LED). A plurality of light sources 301 may be arranged along the side surface of the light guide plate 310. The light source 301 may be arranged to face at least one side surface of the light guide plate 310. A direction perpendicular to the first side surface 311a and the exit surface 312 of the light guide plate 310 is defined as a first direction D. 1 In the first direction D 1 where the first side surface 311a and the second side surface 311b face each other, the backlight unit 300 may have a first light source 301a arranged to face the first side surface 311a of the light guide plate 310, and a second light source 301b arranged to face the second side surface 311b of the light guide plate 310. The first light source 301a and the second light source 301b are preferably arranged parallel to each other.

[0031] The light guide plate 310 is a member that emits light incident from the light source 301 arranged opposite to the side surface 311 toward the liquid crystal panel 200. The light guide plate 310 may be made of a material that is generally used in the field of backlights. FIG. 2A is a perspective view showing an example of the light guide plate used in the first embodiment. FIG. 2B is a plan view schematic diagram of the light guide plate shown in FIG. 2A as viewed from the emission surface side. FIG. 2C is a plan view schematic diagram of the light guide plate shown in FIG. 2A as viewed from the rear surface side. In this specification, the curved surface portions are hatched in the perspective view of the light guide plate and the plan view schematic diagram of the light guide plate as viewed from the emission surface side.

[0032] As shown in FIG. 2A, the light guide plate 310 has a first side surface 311a and an exit surface 312 that outputs light incident from the first side surface 311a to the liquid crystal panel 200. The surface of the light guide plate 310 opposite to the exit surface 312 is a rear surface 313. As shown in FIGS. 2A and 2B, a direction perpendicular to the first side surface 311a is defined as a first direction D. 1 Then, the light guide plate 310 is in the first direction D 1 The light guide plate 310 has a second side surface 311b facing the first side surface 311a in the first direction D. 1 A second direction D perpendicular to 2In the case where a first light source is disposed facing the first side surface 311a and a second light source is disposed facing the second side surface 311b, the first side surface 311a and the second side surface 311b are also referred to as incident surfaces. The incident surface is preferably perpendicular to the back surface 313. The back surface 313 may be flat and not have a curved portion.

[0033] FIG. 2D illustrates the first direction D of the light guide plate shown in FIG. 1 The light guide plate 310 is oriented in a first direction D. 1 The cross section of the first direction D 1 2D, the cross section of the curved surface 311a is perpendicular to the first side surface 311a and the light exit surface 312. As shown in FIG. 1 In the cross section of the light guide plate 310, the light guide plate 310 includes a first curved surface portion 315a arranged between the first side surface 311a and the exit surface 312, and further includes a second curved surface portion 315b arranged between the second side surface 311b and the exit surface 312. By providing a curved surface portion between the entrance surface and the exit surface of the light guide plate 310, it is possible to prevent excessive light from being concentrated at the outer edge of the light guide plate 310 and to increase the amount of light emitted in an oblique direction. By increasing the amount of light emitted in an oblique direction, it is possible to improve the uniformity of the luminance in the user's field of vision, as will be described later. In the first embodiment, the first curved surface portion 315a and the second curved surface portion 315b have the same radius of curvature.

[0034] The curved surface portion may be disposed between the side surface (incident surface) on which the light source is disposed and the exit surface 312, and may extend in the second direction D of the light guide plate. 2 FIG. 2E shows the cross section of the light guide plate in the second direction D 2 1 is a schematic cross-sectional view of the light guide plate in the second direction D 2 If the cross section is not arranged in the second direction D, as shown in FIG. 2 The cross-sectional shape at may be rectangular.

[0035] FIG. 3 is a schematic plan view of a light guide plate having a plurality of recesses and a plurality of linear portions and a light source viewed from the emission surface side. FIG. 4 is a schematic plan view of a light guide plate having a plurality of recesses and a plurality of linear portions and a light source viewed from the rear surface side. FIG. 5 is a schematic cross-sectional view taken along line X1-X2 in FIG. 3 and FIG. 4. FIG. 6 is a schematic cross-sectional view taken along line X3-X4 in FIG. 3 and FIG. 4. As shown in FIG. 3, the light guide plate 310 preferably has a plurality of linear portions 312a extending in the first direction on the emission surface 312. Note that in FIG. 2A and FIG. 2C, the linear portions are omitted in order to explain the position of the curved surface portion. In addition, as shown in FIG. 2C, the light guide plate 310 preferably has a plurality of recesses 313a recessed toward the emission surface 312 on the rear surface 313 opposite to the emission surface 312. By having the above-mentioned plurality of linear portions 312a and the plurality of recessed portions 313a, the light guide plate 310 can efficiently emit light incident on the entrance surface to the liquid crystal panel 200 from the exit surface.

[0036] As shown in FIGS. 3 and 6, the linear portions 312a are aligned in a first direction D 1 The triangular prism extends in the second direction D 2 In addition, the plurality of linear portions may be arranged in the first direction D 1 A semi-cylindrical lenticular lens extending in a second direction D 2 A plurality of such sensors may be arranged in the same area.

[0037] The recesses 313a may be in a dot pattern in which each recess has a semispherical shape, as shown in Figures 4 to 6. Furthermore, each recess may have a pyramid shape, such as a cone or a pyramid.

[0038] FIG. 7 is a schematic plan view illustrating an example of the planar shape of the light guide plate. Examples of the planar shape of the light guide plate 310 as viewed from the emission surface side or the back surface side include a square (see FIGS. 2B and 2C) and a quadrangle such as a rectangle (FIG. 7(a)). An inclined surface or a curved surface may be provided between the first side surface 311a or the second side surface 311b and the third side surface 314a or the fourth side surface 314b. The length of the first side surface 311a along the second direction D2 and the length of the second side surface 311b along the second direction D2 may be the same or different. Specifically, examples include an octagon having inclined surfaces at four corners of a square or a rectangle (see FIGS. 7(b) and (c)), a hexagon having inclined surfaces at two corners of a square or a rectangle (see FIG. 7(d)), and the like. The light guide plate 310 only needs to have at least an incident surface (first side surface 311a) facing the first light source, and examples of the shape of the light guide plate 310 include a regular hexagon (see FIG. 7(e)), a hexagon whose diameter in the first direction is longer than its diameter in the second direction (see FIG. 7(f)), and a hexagon in which the length of the first side surface 311a along the second direction D2 is different from the length of the second side surface 311b along the second direction D2 (see FIG. 7(g)).

[0039] The reflective sheet 302 is disposed to improve the efficiency of light utilization, and is not particularly limited as long as it reflects light incident from the front of the light guide plate 310 (the liquid crystal panel 200 side).

[0040] The optical sheet 303 is not particularly limited as long as it controls the characteristics of the light incident on the liquid crystal panel 200, and examples thereof include a diffusion sheet, a lens sheet, a brightness improvement sheet, and a viewing angle suppression sheet.

[0041] FIG. 8 is a schematic cross-sectional view illustrating a display method of the liquid crystal module shown in FIG. 1. The liquid crystal module of this embodiment has a folded optical lens. The light L1 to L5 emitted from the backlight unit 300 passes through the liquid crystal panel 200 and is emitted to the lens unit 100 side. The light incident on the second lens 102 passes through the second lens 102 and is reflected by the semi-transmissive film 101a of the first lens 101 to the second lens 102 side. The light reflected on the second lens 102 side passes through the second lens 102 and is reflected by the semi-transmissive film 102a of the second lens 102 to the first lens 101 side. The light reflected on the first lens 101 side passes through the first lens 101 and is incident on the user's eye, and forms an image on the user's retina. In addition to the above-described light, there is also light reflected and transmitted by the semi-transmissive films 101a and 102a, but the description thereof will be omitted. The angle of light incident on the user's eye is adjusted by the lens unit 100 disposed on the user's side of the liquid crystal panel 200.

[0042] Depending on the characteristics of the eyepiece optical system, some of the light emitted in an oblique direction may be emitted further out than L1 and L5 in FIG. 8, which is far outside the viewing angle, and in this case, the effective uniformity of the luminance in the field of view perceived by the user is reduced. In the conventional backlight unit, the light guide plate is designed to increase the uniformity of the luminance in the front field of view, and the light from the light source is configured to rise in the normal direction over the entire surface. Therefore, even when the conventional backlight unit is used, the luminance in the emission directions of L2 to L4 in FIG. 8 is high, and the effective uniformity of the luminance perceived by the user remains low. On the other hand, the present invention covers the decrease in luminance near the outer edge of the liquid crystal module caused by the characteristics of the eyepiece optical system by providing a curved portion on the light guide plate 310, and expands the emission directions of L2 to L4 shown in FIG. 8 to the angles of L1 and L5, thereby improving the uniformity of the luminance in the field of view of the user. In embodiment 1, by providing a curved portion between the entrance surface and exit surface of light guide plate 310, the angle of light emitted from light guide plate 310 toward liquid crystal panel 200 can be adjusted, and the amount of light emitted in an oblique direction can be increased.

[0043] (Head-mounted display) The liquid crystal module can be suitably used in a head mounted display (HMD). A head mounted display is a display that can be worn on a user's head, and has, for example, a goggle shape, with the display positioned in front of the user's eyes when worn. Such a head mounted display is suitable for viewing content compatible with VR (virtual reality) technology and AR (augmented reality) technology.

[0044] The HMD preferably includes the liquid crystal module for the right eye and the liquid crystal module for the left eye. That is, it is preferable to have two liquid crystal modules for the right eye and the left eye. Furthermore, the HMD may have a support part for mounting on the user's head.

[0045] <Embodiment 2> Fig. 9A is a perspective view showing an example of a light guide plate used in the embodiment 2. Fig. 9B is a plan view schematic diagram of the light guide plate shown in Fig. 9A as viewed from the light output surface side. Fig. 9C is a view of the light guide plate shown in Fig. 9A in a first direction D. 1 9D is a schematic cross-sectional view of the light guide plate shown in FIG. 2 9A is a schematic cross-sectional view taken in FIG. 9A. A schematic plan view of the light guide plate shown in FIG. 9A as seen from the rear side is omitted because it is the same as FIG.

[0046] As shown in FIGS. 9A to 9C, similarly to the first embodiment, the curved surface portion is 1 In the cross section of the light emitting surface 311, the light emitting surface 311 includes a first curved surface portion 315a disposed between the first side surface 311a and the light emitting surface 312, and a second curved surface portion 315b disposed between the second side surface 311b and the light emitting surface 312. Furthermore, in the second embodiment, as shown in Figs. 9A, 9B, and 9D, the curved surface portion is oriented in a second direction D 2 In the cross section of the second direction D, the third curved surface portion 315c is disposed between the third side surface 314a and the light exit surface 312, and the fourth curved surface portion 315d is disposed between the fourth side surface 314b and the light exit surface 312. 2 The cross section is parallel to the first side surface 311 a and perpendicular to the emission surface 312 .

[0047] If the horizontal direction when the user wears the head mounted display is the left-right direction, and the direction perpendicular to the left-right direction is the up-down direction, the left-right direction of the light guide plate (first direction D 1 ) in the vertical direction of the light guide plate (second direction D 2 By forming the third curved surface portion 315c and the fourth curved surface portion 315d on the first curved surface portion 315a, the second curved surface portion 315b, the third curved surface portion 315c, and the fourth curved surface portion 315d, a decrease in brightness can be prevented not only in the left-right direction but also in the up-down direction. The radii of curvature of the first curved surface portion 315a, the second curved surface portion 315b, the third curved surface portion 315c, and the fourth curved surface portion 315d may be the same or different.

[0048] A preferred combination of the first lens 101 and the second lens 102 in the second embodiment is an aspheric lens and a convex meniscus lens.

[0049] <Embodiment 3> In the third embodiment, the radius of curvature of the first curved surface portion of the light guide plate is different from the radius of curvature of the second curved surface portion. Fig. 10 is a cross-sectional schematic diagram showing an example of a liquid crystal module of the third embodiment. Fig. 11A is a perspective view showing an example of a light guide plate used in the third embodiment. Fig. 11B is a plan schematic diagram of the light guide plate shown in Fig. 11A as viewed from the emission surface side. Fig. 11C is a cross-sectional schematic diagram of the light guide plate shown in Fig. 11A as viewed in a first direction D. 1 11A is a cross-sectional schematic diagram of the light guide plate in the second direction D 2 11A is omitted because it is the same as Fig. 2E. A plan view of the light guide plate shown in Fig. 11A as seen from the rear side is omitted because it is the same as Fig. 2C.

[0050] As shown in FIGS. 11A to 11C, similarly to the first embodiment, the curved surface portion is 1In the cross section of the light emitting element 310, the light emitting element 310 includes a first curved surface portion 315a disposed between the first side surface 311a and the light emitting surface 312, and a second curved surface portion 315b disposed between the second side surface 311b and the light emitting surface 312. In the third embodiment, the radius of curvature of the first curved surface portion 315a is different from the radius of curvature of the second curved surface portion 315b. The radius of curvature of the second curved surface portion 315b may be larger than the radius of curvature of the first curved surface portion 315a.

[0051] FIG. 12 is a schematic cross-sectional view of a head mounted display using the liquid crystal module of the third embodiment. FIG. 12 is a schematic horizontal cross-sectional view of the head mounted display. In the third embodiment, the HMD 1000 includes a liquid crystal module for a right eye and a liquid crystal module for a left eye. In the light guide plate 310 included in the liquid crystal module for the right eye and the left eye, the radius of curvature of the curved surface portion (second curved surface portion 315b in FIG. 12) close to the center (nose) of the user's face is larger than the radius of curvature of the curved surface portion (first curved surface portion 315a in FIG. 12) close to the outer side (ear) of the user's face in the use state. By changing the shape of the light guide plate in the liquid crystal module for the right eye and the liquid crystal module for the left eye in accordance with the lens apex angle in this way, the effective luminance can be increased, and low power consumption and high resolution can be expected.

[0052] A preferred combination of the first lens 101 and the second lens 102 in the third embodiment is an aspheric lens and a convex meniscus lens.

[0053] Embodiments 1 to 3 may be combined as appropriate, and in embodiments 2 and 3, light guide plate 310 preferably has a plurality of linear portions extending in the first direction on the exit surface, as in embodiment 1. Light guide plate 310 preferably has a plurality of recesses recessed toward the exit surface on the rear surface opposite the exit surface. Examples of the linear portions and recesses are the same as those in embodiment 1.

[0054] In the third embodiment, similarly to the second embodiment, the curved surface portion is 2In the cross section, it may include a third curved surface portion 315c arranged between the third side surface 314a and the exit surface 312, and a fourth curved surface portion 315d arranged between the fourth side surface 314b and the exit surface 312.

[0055] <Embodiment 4> Fig. 13 is a cross-sectional view showing an example of a liquid crystal module according to embodiment 4. Fig. 14A is a perspective view showing an example of a light guide plate used in embodiment 4. Fig. 14B is a plan view showing the light guide plate shown in Fig. 14A from the light output surface side. Fig. 14C is a cross-sectional view showing the first direction D of the light guide plate shown in Fig. 14A. 1 14D is a cross-sectional schematic diagram of the light guide plate shown in FIG. 2 14A to 14D, the liquid crystal module of the fourth embodiment has a first direction D perpendicular to the first side surface 311a and the light-emitting surface 312. 1 13, rear surface 313 may be flat without having a curved portion.

[0056] The light guide plate of the fourth embodiment is a light guide plate having a concave curved surface. By using such a shape, the angle of the light emitted toward the liquid crystal panel 200 can be adjusted and the amount of light emitted in an oblique direction can be increased, thereby improving the brightness in the peripheral vision.

[0057] A preferred combination of the first lens 101 and the second lens 102 in the fourth embodiment is an aspheric lens and a convex meniscus lens.

[0058] FIG. 15 is a schematic plan view of a light guide plate having a plurality of recesses and a plurality of linear portions and a light source viewed from the emission surface side. FIG. 16 is a schematic plan view of a light guide plate having a plurality of recesses and a plurality of linear portions and a light source viewed from the rear surface side. FIG. 17 is a schematic cross-sectional view taken along line X5-X6 in FIG. 15 and FIG. 16. FIG. 18 is a schematic cross-sectional view taken along line X7-X8 in FIG. 15 and FIG. 16. In the fourth embodiment, similarly to the first embodiment, the light guide plate 310 preferably has a plurality of linear portions extending in the first direction on the emission surface. In addition, the light guide plate 310 preferably has a plurality of recesses recessed toward the emission surface side on the rear surface opposite to the emission surface. Examples of the plurality of linear portions and the plurality of recesses are the same as those in the first embodiment. [Explanation of symbols]

[0059] 1: LCD module 100: Lens unit 101: First Lens 101a, 102a: Semi-permeable membrane 102: Second Lens 200: LCD panel 201: TFT substrate 202: Color filter substrate 203: Liquid crystal layer 204: Sealing material 205: Display Driver Integrated Circuit (DDIC) 206: Flexible printed circuit board (FPC) for driving liquid crystal panels 300: Backlight unit 301: Light source 301a: First Light Source 301b: Second Light Source 302: Reflective sheet 303: Optical sheet 304: Flexible printed circuit board (FPC) for mounting light source 305: Cabinet 310: Light guide plate 311: Side 311a: First aspect 311b: The second aspect 312: Exit surface 312a: Linear part 313: Back 313a: Recess 314a: The third aspect 314b: The fourth aspect 315a: First curved surface portion 315b: Second curved surface 315c: Third curved section 315d: Fourth curved section 316: Curved surface part 401: Double-sided tape for fixing 1000:HMD

Claims

1. a lens unit including at least a first lens, a liquid crystal panel, and a backlight unit, in this order; the backlight unit includes a light guide plate and a first light source disposed opposite a first side surface of the light guide plate; the light guide plate has the first side surface and an exit surface that outputs light incident from the first side surface toward the liquid crystal panel, and has a curved portion in a cross section in a first direction perpendicular to the first side surface and the exit surface.

2. The liquid crystal module according to claim 1 , wherein the curved surface portion includes a first curved surface portion disposed between the first side surface and the light exit surface in a cross section in the first direction.

3. the light guide plate has a second side surface facing the first side surface in the first direction, the backlight unit has a second light source disposed opposite the second side surface of the light guide plate, The liquid crystal module according to claim 2 , wherein the curved surface portion includes a second curved surface portion disposed between the second side surface and the light exit surface in a cross section in the first direction.

4. 4. The liquid crystal module according to claim 3, wherein the first curved surface portion and the second curved surface portion have different radii of curvature.

5. The light guide plate further has a third side surface and a fourth side surface opposed to each other in a second direction perpendicular to the first direction, 4. The liquid crystal module according to claim 2 or 3, wherein the curved surface portion includes, in a cross section in the second direction, a third curved surface portion arranged between the third side surface and the exit surface, and a fourth curved surface portion arranged between the fourth side surface and the exit surface.

6. The liquid crystal module according to claim 1 , wherein the curved surface portion is disposed at a center of the light exit surface and curves toward an opposite side to the liquid crystal panel.

7. The liquid crystal module according to claim 1 , wherein the light guide plate has a plurality of linear portions extending in the first direction on the exit surface, and a plurality of recesses recessed toward the exit surface on a rear surface opposite the exit surface.

8. the lens unit further includes a second lens disposed between the first lens and the liquid crystal panel; 2. The liquid crystal module according to claim 1, wherein the first lens and the second lens each have a semi-transmissive film on the liquid crystal panel side.

9. A head mounted display comprising: a liquid crystal module according to claim 1 for a right eye; and a liquid crystal module according to claim 1 for a left eye.

Images