Display device

Abstract

Provided is a display device that can switch to not displaying an infinite mirror image.　A display device according to the present invention includes a liquid crystal display unit (120), a partial transmission plate (150) that is provided on a back surface side of the liquid crystal display unit, a total reflection mirror (140) that is provided on the reverse side of the partial transmission plate from the liquid crystal display unit so as to be opposite the partial transmission plate with a gap therebetween, and a light source (160) that outputs light into the area between the partial transmission plate and the total reflection mirror, the center axis of light emission being directed toward the partial transmission plate or the total reflection mirror.

Description

display device

[0001] The present disclosure relates to a display device.

[0002] Conventionally, there has been a display device including a half mirror, a total reflection mirror, and a light source provided between the half mirror and the total reflection mirror. When a viewer looks into the display device from the display surface, images between the half mirror and the total reflection mirror overlap one another in the depth direction, and the images appear to become smaller as they go further back (see, for example, Patent Document 1).

[0003] Japanese Utility Model Application Publication No. 56-139191

[0004] Hereinafter, as described above, an image between a half mirror and a total reflection mirror is overlapped in the depth direction due to multiple reflections, and an image that appears to become smaller the further it goes is referred to as an infinite mirror image.

[0005] The infinity mirror image of a conventional display device is always displayed, and therefore the infinity mirror image cannot be hidden.

[0006] Therefore, an object of the present invention is to provide a display device that can switch between displaying and hiding an infinity mirror image.

[0007] A display device according to an embodiment of the present disclosure includes a liquid crystal display unit, a partially transmitting plate provided on the rear side of the liquid crystal display unit, a total reflection mirror provided on the opposite side of the liquid crystal display unit from the partially transmitting plate, with a gap between the partially transmitting plate and the total reflection mirror facing the partially transmitting plate, and a light source having a central axis of light emission directed toward the partially transmitting plate or the total reflection mirror, and outputting light to the area between the partially transmitting plate and the total reflection mirror.

[0008] It is possible to provide a display device that can switch between displaying and hiding infinite mirror images.

[0009] 1 is a diagram showing an example of a cross-sectional configuration of a display device of Embodiment 1. FIG. 2 is a diagram showing an example of a configuration of a glass plate of a liquid crystal display unit of the display device of Embodiment 1. FIG. 3 is a diagram showing an example of a configuration of a glass plate of a liquid crystal display unit of the display device of Embodiment 1. FIG. 4 is a diagram showing an example of a characteristic of visible light transmittance of a liquid crystal display unit with respect to a voltage applied to the liquid crystal display unit of the display device of Embodiment 1. FIG. 5 is a cross-sectional view showing an example of a configuration of a display device of a modified example of Embodiment 1. FIG. 6 is a cross-sectional view showing an example of a configuration of a display device of a modified example of Embodiment 1. FIG. 7 is a cross-sectional view showing an example of a configuration of a display device of a modified example of Embodiment 1. FIG. 8 is a cross-sectional view showing an example of a configuration of a display device of a modified example of Embodiment 1. FIG. 9 is a cross-sectional view showing an example of a configuration of a display device of a modified example of Embodiment 1. FIG. 10 is a cross-sectional view showing an example of a configuration of a display device of a modified example of Embodiment 1. FIG. 11 is a cross-sectional view showing an example of a configuration of a display device of a modified example of Embodiment 1. FIG. 12 is a cross-sectional view showing an example of a configuration of a display device of a modified example of Embodiment 1. Fig. 1 is a cross-sectional view showing an example of the configuration of a display device according to a modification of embodiment 2. Fig. 2 is a cross-sectional view showing an example of the configuration of a display device according to a modification of embodiment 2. Fig. 3 is a cross-sectional view showing an example of the configuration of a display device according to a modification of embodiment 2. Fig. 4 is a diagram showing an actual measurement example of gradation control in a display device according to a modification of embodiment 2. Fig. 5 is a diagram showing an actual measurement example of gradation control in a display device according to a modification of embodiment 2.

[0010] Hereinafter, an embodiment to which the display device of the present disclosure is applied will be described.

[0011] In the following description, the XYZ coordinate system is defined. The X axis is an example of the first axis, the Y axis is an example of the second axis, and the Z axis is an example of the third axis. The direction parallel to the X axis (X direction), the direction parallel to the Y axis (Y direction), and the direction parallel to the Z axis (Z direction) are perpendicular to each other. In addition, in the following, a planar view refers to an XY plane view. In the following description, the +Z direction is described as the upward direction and the −Z direction is described as the downward direction, as an example, but this does not represent a universal vertical relationship. In addition, in the following description, the length, width, thickness, etc. of each part may be exaggerated to make the configuration easier to understand.

[0012] 1 is a diagram showing an example of a cross-sectional configuration of a display device 100 according to embodiment 1. The display device 100 includes a case 110, a liquid crystal display unit 120, an anti-reflection layer 130, a total reflection mirror 140, a partial reflection mirror 150, and a light source 160. The partial reflection mirror 150 is an example of a partially transmitting plate.

[0013] The upper surface of the anti-reflection layer 130 is the display surface of the display device 100. A transparent plate-like member such as a cover glass may be provided between the anti-reflection layer 130 and the polarizing plate 125 of the liquid crystal display unit 120.

[0014] The display device 100 can display an image with a sense of depth because the light output from the light source 160 is repeatedly reflected between the total reflection mirror 140 and the partial reflection mirror 150, causing reflected virtual images to overlap at equal intervals and appearing to become smaller the further back they are.

[0015] Hereinafter, such an image with a sense of depth due to multiple reflections will be referred to as an “infinity mirror image.” An infinity mirror image is easier to see when viewed from a slightly oblique direction rather than from directly in front of the display device 100 in the +Z direction.

[0016] <Case 110> The case 110 is the housing of the display device 100. For example, the case 110 is box-shaped and rectangular in plan view. The case 110 has an opening at the top and an internal space that is connected to the opening and extends downward. Such an internal space is an example of a region, and more specifically, an example of a three-dimensional region. A total reflection mirror 140 is disposed at the bottom of the internal space of the case 110, and a partial reflection mirror 150 is provided at the opening at the top. The case 110 also has convex portions 111 at the center in the Z direction of each of the four inner surfaces, protruding toward the center of the internal space in plan view. Multiple light sources 160 are provided at the tips of the convex portions 111. Note that the light sources 160 may be provided on the inner wall of the case 110 without providing the convex portions 111. The internal space of the case 110 may also be sealed with, for example, a transparent resin. The portion of the internal space sealed with the transparent resin in this manner is a three-dimensional region within the case 110.

[0017] <Liquid Crystal Display Unit 120> The liquid crystal display unit 120 is provided on the case 110. The liquid crystal display unit 120 has a polarizing plate 121, a glass plate 122, a sealing seal 123, a glass plate 124, a polarizing plate 125, and a liquid crystal layer 126. The glass plate 124 is an example of a first glass plate, and the glass plate 122 is an example of a second glass plate. The liquid crystal display unit 120 is, for example, a liquid crystal display unit driven by a passive driving method.

[0018] Polarizing plate 121 is provided on the lower surface of glass plate 122, and the lower surface of polarizing plate 121 is in contact with the upper surface of partial reflection mirror 150. Polarizing plate 121 has a predetermined polarization direction corresponding to the alignment of liquid crystal in liquid crystal layer 126.

[0019] The glass plate 122 is a transparent glass plate provided on the lower side of the liquid crystal layer 126. The lower side of the liquid crystal layer 126 is an example of a second side (-Z side) opposite the first side (+Z side) of the liquid crystal layer 126 opposite the partial reflection mirror 150. Being transparent means that light passes through. Electrodes are provided on the upper surface of the glass plate 122. The position of the switchable region 120A defined by the electrodes on the upper surface of the glass plate 122 and the electrodes on the lower surface of the glass plate 124 is indicated by dashed lines. The electrodes provided on the upper surface of the glass plate 122 can be made of a transparent conductive film, and as an example, are made of an ITO (indium tin oxide) film. Details of the electrodes provided on the upper surface of the glass plate 122 will be described later using Figures 2A and 2B.

[0020] The sealing seal 123 is a frame-shaped member provided between the glass plates 122 and 124. Here, since the display device 100 is rectangular in plan view, for example, the sealing seal 123 has a rectangular ring shape in plan view. The sealing seal 123 is made of an insulating material, for example, resin. The sealing seal 123 is bonded between the glass plates 122 and 124, and seals the liquid crystal layer 126 together with the glass plates 122 and 124.

[0021] The glass plate 124 is a transparent glass plate provided above the liquid crystal layer 126. The upper surface side of the liquid crystal layer 126 is an example of a first side (+Z direction side) opposite the partial reflection mirror 150 with respect to the liquid crystal layer 126. The meaning of "transparent" is the same as that of the glass plate 122. An electrode is provided on the lower surface of the glass plate 124. The position of the switchable region 120A defined by the electrode on the lower surface of the glass plate 124 and the electrode on the upper surface of the glass plate 122 is indicated by a dashed line. The electrode provided on the lower surface of the glass plate 124 can be made of a transparent conductive film, and is made of an ITO film as an example. Details of the electrode provided on the lower surface of the glass plate 124 will be described later using Figures 2A and 2B.

[0022] The polarizing plate 125 is provided on the glass plate 124. The polarizing plate 125 has a predetermined polarization direction.

[0023] The liquid crystal layer 126 is provided in a space sealed by the glass plates 122 and 124 and the sealing seal 123. When a voltage is applied between the electrode on the upper surface of the glass plate 122 and the electrode on the lower surface of the glass plate 124, the orientation direction of the liquid crystal molecules in the liquid crystal layer 126 changes, and the light transmittance when viewed from the top changes.

[0024] The liquid crystal layer 126 is configured to become transparent and transmit light when an electric field is applied, and to become opaque and not transmit light when no electric field is applied. Control of the transmittance of the liquid crystal layer 126 will be described later with reference to FIG.

[0025] <Anti-reflection layer 130> The anti-reflection layer 130 is provided on the top surface of the display device 100. The anti-reflection layer 130 is, for example, configured with an AR (Anti-Reflection) film. The anti-reflection layer 130 may be provided on the surface of a transparent plate-like member such as a cover glass. Note that such a transparent plate-like member such as a cover glass is an example of a protective plate.

[0026] <Total Reflection Mirror 140> Total reflection mirror 140 is provided at the bottom of the internal space of case 110, and its upper surface is a reflective surface that totally reflects light. As an example, total reflection mirror 140 can be produced by polishing the upper surface of a plate-like member and evaporating aluminum thereon. Note that total reflection mirror 140 is not limited to this configuration, and may be a mirror of any configuration as long as it has a reflective surface that totally reflects light as its upper surface.

[0027] <Partial Reflection Mirror 150> The partial reflection mirror 150 is provided in the opening at the top of the case 110. The light transmittance of the partial reflection mirror 150 may be set to an appropriate value between about 20% and about 80%, for example, and more preferably between about 30% and about 70%. Here, as an example, the light transmittance of the partial reflection mirror 150 is set to 50%.

[0028] The partial reflection mirror 150 transmits a portion of the light that passes through the liquid crystal display unit 120 from the top to the bottom, and reflects the remaining light from the top surface toward the liquid crystal display unit 120. The partial reflection mirror 150 also transmits light that arrives from below from the bottom surface to the top surface, and reflects the remaining light downward from the bottom surface.

[0029] Here, a description will be given of an embodiment in which a partial reflection mirror 150 is used as an example of a partial transmission plate. However, the partial transmission plate may be any plate-shaped member that transmits a portion of incident light. Furthermore, since the surface of such a plate-shaped partially transmitting plate reflects the light that is not transmitted, the partially transmitting plate transmits a portion of the incident light and reflects the remaining light. As an example, the reflectance of the partially transmitting plate may be a very low value of 10% or less. Partial transmission plates other than the partially reflecting mirror 150 will be described later using FIG. 4A .

[0030] <Light Sources 160> A plurality of light sources 160 are provided at the tip of the convex portion 111 of the case 110. The light sources 160 are, for example, light-emitting diodes (LEDs), but may be light-emitting bodies other than LEDs. For example, the convex portion 111 extends from the four inner surfaces of the case 110 toward the center of the internal space of the case 110 in a planar view, and the light sources 160 are arranged in a rectangular ring shape at equal intervals in a planar view. The plurality of light sources 160 are disposed outside the switchable area of ​​the liquid crystal display unit 120 in a planar view. The light sources 160 output light to the space (area) between the partial reflection mirror 150 and the total reflection mirror 140.

[0031] The terminals of each light source 160 are connected to an external device of the display device 100 via wiring or the like (not shown), and the lighting of each light source 160 is controlled by the external device, for example.

[0032] The central axis of the light emission of light source 160 is inclined with respect to a line (a line parallel to the Z axis) perpendicular to the lower surface of partial reflection mirror 150 and the upper surface of total reflection mirror 140. The central axis of the light emission of light source 160 is the central axis of the three-dimensional irradiation range of the light output by light source 160. By inclining the central axis of the light emission of light source 160 with respect to a line (a line parallel to the Z axis) perpendicular to the lower surface of partial reflection mirror 150 and the upper surface of total reflection mirror 140, the light is incident obliquely on total reflection mirror 140 and partial reflection mirror 150, the number of times of multiple reflection increases, and an infinity mirror image with greater depth is obtained.

[0033] For example, the central axis of light emission of light source 160 has an angle of about 70 degrees in absolute value with respect to a line (a line parallel to the Z axis) perpendicular to the lower surface of partial reflection mirror 150 and the upper surface of total reflection mirror 140. In other words, for example, the central axis of light emission of light source 160 has an angle of about 20 degrees upward or downward with respect to the horizontal direction.

[0034] 2A and 2B are diagrams showing the configuration of the glass plates 122 and 124 of the liquid crystal display unit 120. In FIGS. 2A and 2B, an electrode 122A of the glass plate 122 and an electrode 124A of the glass plate 124 are shown in a transparent manner. The electrode 122A is provided over substantially the entire upper surface (surface on the +Z direction side) of the glass plate 122, and the electrode 124A is provided over substantially the entire lower surface (surface on the −Z direction side) of the glass plate 124. The electrodes 122A and 124A can be made of a transparent conductive film, and as an example, are made of an ITO film.

[0035] 2A shows a state in which a control voltage is applied to electrodes 122A and 124A of the liquid crystal display unit 120, and Fig. 2B shows a state in which a control voltage is not applied to electrodes 122A and 124A of the liquid crystal display unit 120. For this reason, Fig. 2A shows an AC-to-DC power supply 10.

[0036] The electrodes 122A and 124A are arranged facing each other. The electrode 122A has two electrodes 1 and one electrode 2. The electrode 124A has one electrode 1 and two electrodes 2. The electrodes 1 of the electrodes 122A and 124A are an example of a pair of first electrodes. The electrodes 2 of the electrodes 122A and 124A are an example of a pair of second electrodes.

[0037] Two electrodes 1 of electrode 122A and one electrode 1 of electrode 124A are connected via wiring or the like (not shown) and configured to be at the same potential. One electrode 2 of electrode 122A and two electrodes 2 of electrode 124A are connected via wiring or the like (not shown) and configured to be at the same potential. Also, as an example, AC-DC voltages V1 and V2 of opposite phase and equal amplitude are applied to electrode 1 of electrode 124A and electrode 2 of electrode 122A, respectively, from AC-DC power supply 10. As shown in the lower part of FIG. 2A , the AC-DC voltages V1 and V2 have a period during one frame in which VLCD (>VGND) is applied and a period in which VGND is applied. VGND is a ground voltage.

[0038] Therefore, when the AC-DC power supply 10 is outputting an AC-DC voltage, a potential difference occurs between the electrodes 1 and 2. Furthermore, when the AC-DC power supply 10 is outputting an AC-DC voltage, two electrodes 1 of the electrode 122A and one electrode 1 of the electrode 124A are at the same potential, and one electrode 2 of the electrode 122A and two electrodes 2 of the electrode 124A are at the same potential.

[0039] 2A and 2B show a switchable area 120A of the liquid crystal display unit 120 according to the configuration of the electrodes 122A and 124A.

[0040] The switchable area 120A is an area of ​​the display surface of the liquid crystal display unit 120 where the image to be displayed can be switched. The switchable area 120A is located in the central portion of the display surface of the liquid crystal display unit 120 in a plan view, excluding a rectangular ring-shaped portion along the outer edge of the display surface. The width of the rectangular ring-shaped portion along the outer edge of the display surface (the width between the outer edge of the display surface and the switchable area 120A) is, for example, approximately 1 mm to 20 mm. Note that the width of the rectangular ring-shaped portion along the outer edge of the display surface may be narrower than 1 mm or wider than 20 mm.

[0041] Within the switchable region 120A, an electrode 2 of the electrodes 122A and an electrode 1 of the electrodes 124A are provided.

[0042] <Electrode 122A> The electrode 122A is configured such that electrode 1, electrode 2, and electrode 1 are arranged in this order from the −X direction side to the +X direction side.

[0043] The electrode 1 on the −X direction side of the electrode 122A is provided closer to the −X direction than the switchable region 120A in the X direction, and extends in the Y direction from the end of the electrode 122A on the −Y direction side to the end on the +Y direction side. The electrode 1 on the +X direction side of the electrode 122A is provided closer to the +X direction than the switchable region 120A in the X direction, and extends from the end of the electrode 122A on the −Y direction side to the end on the +Y direction side.

[0044] Electrode 2 of electrode 122A extends in the X direction within a section between the −X direction end and the +X direction end of switchable region 120A, and extends in the Y direction from the −Y direction end to the +Y direction end of electrode 122A. Electrode 2 of electrode 122A that applies a voltage to switchable region 120A extends to an end in the Y direction (second direction) that intersects with the X direction (first direction) of glass plate 122 in a plan view.

[0045] Electrode 2 of electrode 122A is connected to the AC-DC power supply 10, for example, via a terminal or the like connected to the end of the glass plate 122 on the +Y direction side. This is because if electrode 2 of electrode 122A extends to the end of the glass plate 122, electrode 2 of electrode 122A can be easily connected to the AC-DC power supply 10 outside the liquid crystal display unit 120. Note that electrode 2 of electrode 122A that applies a voltage to the switchable region 120A may be connected to the AC-DC power supply 10 by connecting a terminal or the like to the end of the glass plate 122 on the −Y direction side, for example.

[0046] Furthermore, as an example, the two electrodes 1 of electrode 122A are connected to electrode 1 of electrode 124A by sandwiching a conductor between them. Furthermore, as an example, the two electrodes 1 of electrode 122A may be connected to electrode 1 of electrode 124A via wiring or the like connected to electrode 1 of electrode 124A. Furthermore, as an example, the two electrodes 1 of electrode 122A may be connected to AC-DC power supply 10 via terminals or the like connected to the ends in the −X direction and +X direction. In this way, the two electrodes 1 of electrode 122A and electrode 1 of electrode 124A are maintained at the same potential.

[0047] <Electrode 124A> The electrode 124A is composed of an H-shaped electrode 1 and two rectangular electrodes 2 that are respectively arranged in the two remaining parts of the rectangular electrode 124A excluding the H-shaped electrode 1.

[0048] The electrode 2 on the −Y direction side of the electrode 124A extends within the section between the −X direction end and the +X direction end of the switchable region 120A in the X direction, and is located on the −Y direction side of the switchable region 120A in the Y direction. The electrode 2 on the +Y direction side of the electrode 124A extends within the section between the −X direction end and the +X direction end of the switchable region 120A in the X direction, and is located on the +Y direction side of the switchable region 120A in the Y direction.

[0049] Electrode 1 of electrode 124A is provided in the remaining H-shaped portion of electrode 124A, which is rectangular overall in plan view, excluding the two electrodes 1 described above. Electrode 1 of electrode 124A, which applies a voltage to switchable region 120A, extends to the end of glass plate 124 in the X direction (first direction). Electrode 1 of electrode 124A is connected to AC-DC power supply 10, for example, via a terminal or the like connected to the end of glass plate 124 on the −X direction side.

[0050] This is because, if electrode 1 of electrode 124A extends to the edge of glass plate 124, electrode 1 of electrode 124A can be easily connected to the AC-DC power supply 10 outside liquid crystal display unit 120. Note that electrode 1 of electrode 124A that applies a voltage to switchable region 120A may be connected to the AC-DC power supply 10 by connecting a terminal or the like to the edge of glass plate 124 on the +X direction side, for example.

[0051] As an example, the two electrodes 2 of electrode 124A are connected to the electrodes 2 of electrode 122A by sandwiching a conductor between them and the electrodes 2 of the glass plate 122. Also, as an example, the two electrodes 2 of electrode 124A may be connected to the electrodes 2 of electrode 122A via wiring or the like connected to the electrodes 2 of electrode 122A. Also, as an example, the two electrodes 2 of electrode 124A may be connected to the AC-DC power supply 10 via terminals or the like connected to the ends in the −Y direction and +Y direction. In this way, the two electrodes 2 of electrode 124A and the electrodes 2 of electrode 122A are maintained at the same potential.

[0052] In such electrodes 122A and 124A, in the portion outside the switchable region 120A, within the section in the Y direction between the end on the −Y side and the end on the +Y side of the switchable region 120A, electrode 2 of electrode 122A and electrode 2 of electrode 124A face each other. Electrodes facing each other is synonymous with electrodes overlapping with a gap between them.

[0053] 2A , when an AC-DC voltage is applied between electrodes 1 and 2 from the AC-DC power supply 10, a potential difference occurs between electrodes 1 and 2, and an electric field is generated in a portion of the liquid crystal layer 126 within the switchable region 120A. Even if a potential difference occurs between electrodes 1 and 2 when an AC-DC voltage is applied between electrodes 1 and 2 from the AC-DC power supply 10, no potential difference occurs in a portion of the liquid crystal layer 126 outside the switchable region 120A, and therefore no electric field is generated.

[0054] The liquid crystal layer 126 becomes light-transmitting when an electric field is applied, and becomes light-opaque when no electric field is applied. Therefore, when an AC / DC voltage is applied between electrodes 1 and 2, the switchable region 120A becomes light-transmitting. Furthermore, in the portion of the liquid crystal display unit 120 outside the switchable region 120A, electrodes 1 face each other and electrodes 2 face each other, so even if an AC / DC voltage is applied between electrodes 1 and 2, the liquid crystal layer 126 remains in a light-opaque state.

[0055] Furthermore, when no AC / DC voltage is applied between electrodes 1 and 2, no potential difference occurs between electrodes 1 and 2 in switchable region 120A, and therefore switchable region 120A is in a non-light-transmitting state. Also, in the portion of liquid crystal display unit 120 outside switchable region 120A, opposing electrodes 1 and opposing electrodes 2 are at the same potential, so liquid crystal layer 126 is maintained in a non-light-transmitting state.

[0056] In this way, by switching between a state in which an AC-DC voltage is applied between electrodes 1 and 2 and a state in which an AC-DC voltage is not applied between electrodes 1 and 2, the transmission state of switchable region 120A of liquid crystal display unit 120 can be switched like the shutter of an imaging device. Furthermore, in the portion of liquid crystal display unit 120 outside switchable region 120A, the liquid crystal layer 126 is always maintained in a non-light-transmitting state regardless of whether an AC-DC voltage is applied between electrodes 1 and 2.

[0057] Since the display device 100 is capable of displaying an infinity mirror image, by switching the transparent state of the switchable area 120A of the liquid crystal display unit 120, it is possible to switch between a state in which an infinity mirror image is displayed and a state in which an infinity mirror image is not displayed.

[0058] Note that the space between the glass plates 122 and 124 is sealed by the sealing seal 123 along the outer edges (four sides) of the glass plates 122 and 124, and therefore the electrodes 122A and 124A may be offset inward from the outer edges (four sides) of the glass plates 122 and 124 in a plan view so as not to overlap with the sealing seal 123. However, since the electrodes 122A and 124A are connected to the AC-DC power supply 10 via terminals or the like, it is sufficient that the portions of the electrodes 122A and 124A connected to the terminals or the like extend to the outer edges of the glass plates 122 and 124. Furthermore, in this case, the portions of the glass plates 122 and 124 on which the electrodes 122A and 124A connected to the terminals or the like are formed may protrude outward from the sealing seal 123 in a plan view.

[0059] <Light transmittance in liquid crystal display unit 120> Fig. 3 is a diagram showing an example of the characteristics of the light transmittance of liquid crystal display unit 120 versus the voltage applied to liquid crystal display unit 120. The voltage applied to liquid crystal display unit 120 is an AC-DC voltage of opposite phase that is applied between electrodes 1 and 2. The voltage on the horizontal axis in Fig. 3 represents the amplitude of the AC-DC voltage of opposite phase.

[0060] Here, the solid line indicates the light transmittance characteristics when no polarizing cover is attached to light source 160 (without polarizing cover), and the dashed line indicates the light transmittance characteristics when a polarizing cover is attached to light source 160 (with polarizing cover). The polarization direction of the polarizing cover attached to light source 160 matches the polarization direction of polarizing plate 121 below liquid crystal layer 126.

[0061] When the voltage was between 0.0 V and 2.0 V, the transmittance was a very low value of about 1% to 2% for both the light source 160 with the polarizing cover and the light source 160 without the polarizing cover. This state indicates that no light was transmitted. Furthermore, when the voltage exceeded 2.0 V, the transmittance began to increase rapidly for both the light source 160 with the polarizing cover and the light source 160 without the polarizing cover. The rate at which the transmittance increased for the light source 160 with the polarizing cover was greater than the rate at which the transmittance increased for the light source 160 without the polarizing cover.

[0062] When the voltage exceeded approximately 4.0 V, the transmittance of both the light source 160 with the polarized cover and the light source 160 without the polarized cover became approximately constant. When the voltage was increased to 6.0 V, the maximum transmittance of the light source 160 with the polarized cover was approximately 73%, and the maximum transmittance of the light source 160 without the polarized cover was approximately 37%. The maximum transmittance of the light source 160 with the polarized cover was approximately twice the maximum transmittance of the light source 160 without the polarized cover.

[0063] In this way, it was confirmed that by controlling the voltage applied to electrodes 1 and 2, the transmittance of the liquid crystal display unit 120 can be switched between a very low value of approximately 1% to approximately 2% and a value that allows light to pass through, such as approximately 37% or approximately 73%.

[0064] For example, to switch switchable region 120A from an opaque state to a transmissive state in one go, the voltage applied to electrodes 1 and 2 can be increased from 0.0 V to 6.0 V in one go. Alternatively, to switch switchable region 120A from an opaque state to a transmissive state gradually, the voltage applied to electrodes 1 and 2 can be increased gradually from 2.0 V to 4.0 V.

[0065] <Display Devices 100A to 100G as Modifications of Embodiment 1> Figures 4A to 4G are cross-sectional views showing examples of the configuration of display devices 100A to 100G as modification examples of Embodiment 1. Figures 4A to 4G show cross-sectional configurations on the XZ plane corresponding to the display device 100 shown in Figure 1. Furthermore, the same components as those of the display device 100 shown in Figure 1 are given the same reference numerals, and descriptions thereof will be omitted.

[0066] <Display Device 100A> The display device 100A shown in Fig. 4A includes a hard coat 150A instead of the partially reflective mirror 150 of the display device 100 shown in Fig. 1. The hard coat 150A is an example of a partially transmissive plate.

[0067] The hard coat 150A is, for example, a semi-transparent, hard resin layer. The hard coat 150A has a reflectance lower than a transmittance. For example, the reflectance of the hard coat 150A may be approximately 10% or less than 10%. That is, the transmittance of the hard coat 150A may be approximately 90% or greater than 90%.

[0068] The hard coat 150A transmits a portion of the light that passes through the liquid crystal display unit 120 from the top to the bottom, and reflects the remaining light from the top surface toward the liquid crystal display unit 120. The hard coat 150A also transmits light that arrives from below from the bottom surface to the top surface, and reflects the remaining light downward from the bottom surface.

[0069] Therefore, in the display device 100A including the hard coat 150A, the infinity mirror image itself is displayed fainter due to the lower reflectivity compared to the partial reflection mirror 150, but the infinity mirror image itself can be displayed in the same way as the display device 100 including the partial reflection mirror 150. Therefore, even if the hard coat 150A is used instead of the partial reflection mirror 150, it is possible to provide a display device 100A that can switch the infinity mirror image on and off. Furthermore, since the hard coat 150A is cheaper than the partial reflection mirror 150, it is possible to provide a display device 100A with reduced manufacturing costs. Note that the light source 160 may be provided on the inner wall of the case 110, etc., without providing the convex portion 111.

[0070] <Display device 100B> Display device 100B shown in Fig. 4B includes a reflective polarizing plate 121B instead of polarizing plate 121 and partial reflection mirror 150 of display device 100 shown in Fig. 1. Reflective polarizing plate 121B is included in liquid crystal display unit 120B. Liquid crystal display unit 120B has a reflective polarizing plate 121B instead of polarizing plate 121 shown in Fig. 1.

[0071] The reflective polarizing plate 121B functions as a polarizing plate similar to the polarizing plate 121, and also has the same function as the partial reflection mirror 150. The reflective polarizing plate 121B is an example of a partial transmission plate. The light transmittance of the reflective polarizing plate 121B may be set to an appropriate value between about 20% and about 80%, for example, and more preferably between about 30% and about 70%. Here, as an example, the light transmittance of the reflective polarizing plate 121B is assumed to be 50%.

[0072] Reflective polarizing plate 121B polarizes a portion of the light that passes through liquid crystal display unit 120 from the top to the bottom and transmits it from the top to the bottom, and reflects the remaining light from the top surface toward liquid crystal display unit 120. Reflective polarizing plate 121B also transmits and polarizes light that arrives from below from the bottom to the top, and reflects the remaining light downward from the bottom surface.

[0073] Therefore, the display device 100B including the reflective polarizing plate 121B can operate in the same manner as the display device 100 including the polarizing plate 121 and the partial reflection mirror 150. Therefore, it is possible to provide the display device 100B that can switch the infinite mirror image to be hidden or not. Note that the light source 160 may be provided on the inner wall of the case 110 without providing the convex portion 111.

[0074] <Display device 100C> The display device 100C shown in Fig. 4C has a configuration in which the switchable region 120A of the display device 100 shown in Fig. 1 is enlarged in plan view. In the cross section of Fig. 4C, the switchable region 120A is located over the entire portion of the glass plates 122 and 124 where the sealing seal 123 does not overlap.

[0075] To realize such an enlarged switchable area 120A, for example, all of the electrodes 122A shown in Figures 2A and 2B may be configured with electrodes 1 and all of the electrodes 124A may be configured with electrodes 2. In this case, there will be no portion outside the switchable area 120A shown in Figures 2A and 2B where the electrodes 1 face each other or the electrodes 2 face each other.

[0076] In the display device 100C, the enlarged switchable area 120A can be switched between a transparent state and a non-transparent state to switch between a state in which the infinity mirror image is displayed and a state in which it is not displayed. Therefore, it is possible to provide a display device 100C that can switch between a state in which the infinity mirror image is displayed and a state in which it is not displayed. Note that the light source 160 may be provided on the inner wall of the case 110 without providing the protrusion 111.

[0077] The enlarged switchable area 120A described here may be applied to the display device 100A shown in FIG. 4A and the display device 100B shown in FIG. 4B.

[0078] <Display Device 100D> Display device 100D shown in Fig. 4D has a configuration in which multiple light sources 160 of display device 100 shown in Fig. 1 are attached to the lower surface of partial reflection mirror 150. In this configuration, convex portion 111 is not necessary. Multiple light sources 160 are arranged outside switchable region 120A along switchable region 120A in a planar view. Furthermore, multiple light sources 160 are arranged facing diagonally downward toward the center of total reflection mirror 140. In other words, the central axis of light emission of light source 160 is inclined with respect to a line (a line parallel to the Z axis) perpendicular to the lower surface of partial reflection mirror 150 and the upper surface of total reflection mirror 140.

[0079] In display device 100D including multiple light sources 160 arranged in this manner, a portion of the light output from light source 160 and reflected by total reflection mirror 140 passes through partial reflection mirror 150, and the remaining light is reflected again by total reflection mirror 140. By repeating this operation, reflected virtual images obtained between total reflection mirror 140 and partial reflection mirror 150 are overlapped at equal intervals in the depth direction while gradually becoming smaller, and an infinite mirror image is obtained, similar to display device 100 shown in FIG.

[0080] <Display Device 100E> Display device 100E shown in Fig. 4E has a configuration in which multiple light sources 160 of display device 100 shown in Fig. 1 are attached to the upper surface of total reflection mirror 140. In this configuration, convex portion 111 is not necessary. Multiple light sources 160 are arranged outside switchable region 120A along switchable region 120A in a planar view. Furthermore, multiple light sources 160 are arranged facing diagonally upward toward the center of partial reflection mirror 150. In other words, the central axis of light emission of light source 160 is inclined with respect to a line (a line parallel to the Z axis) perpendicular to the lower surface of partial reflection mirror 150 and the upper surface of total reflection mirror 140.

[0081] In display device 100E including multiple light sources 160 arranged in this manner, a portion of the light output from light source 160 passes through partial reflection mirror 150, and the remaining light is reflected by total reflection mirror 140 and again enters partial reflection mirror 150. By repeating this operation, the reflected virtual images obtained between total reflection mirror 140 and partial reflection mirror 150 are overlapped at equal intervals in the depth direction while gradually becoming smaller, and an infinite mirror image is obtained, similar to display device 100 shown in FIG.

[0082] <Display Device 100F> Display device 100F shown in Fig. 4F has a configuration in which multiple light sources 160 of display device 100 shown in Fig. 1 are attached to convex portion 111 facing diagonally upward. Convex portion 111 of display device 100F is inclined so that light sources 160 face diagonally upward. Multiple light sources 160 are arranged facing diagonally upward toward the center of partial reflection mirror 150. In other words, the central axis of light emission of light source 160 is inclined with respect to a line (a line parallel to the Z axis) perpendicular to the lower surface of partial reflection mirror 150 and the upper surface of total reflection mirror 140.

[0083] In display device 100F including multiple light sources 160 arranged in this manner, a portion of the light output from light source 160 passes through partial reflection mirror 150, and the remaining light is reflected by total reflection mirror 140 and again enters partial reflection mirror 150. By repeating this operation, the reflected virtual images obtained between total reflection mirror 140 and partial reflection mirror 150 are overlapped at equal intervals in the depth direction while gradually becoming smaller, and an infinite mirror image is obtained, similar to display device 100 shown in Fig. 1. Note that light source 160 may be provided on the inner wall of case 110 or the like without providing protrusion 111.

[0084] <Display Device 100G> Display device 100G shown in Fig. 4G has a configuration in which multiple light sources 160 of display device 100 shown in Fig. 1 are attached to convex portion 111 facing diagonally downward. Convex portion 111 of display device 100G is inclined so that light sources 160 face diagonally downward. Multiple light sources 160 are arranged facing diagonally downward toward the center of total reflection mirror 140. In other words, the central axis of light emission of light source 160 is inclined with respect to a line (a line parallel to the Z axis) perpendicular to the lower surface of partial reflection mirror 150 and the upper surface of total reflection mirror 140.

[0085] In display device 100G including multiple light sources 160 arranged in this manner, a portion of the light output from light source 160 and reflected by total reflection mirror 140 passes through partial reflection mirror 150, and the remaining light is reflected again by total reflection mirror 140. By repeating this operation, the reflected virtual images obtained between total reflection mirror 140 and partial reflection mirror 150 are overlapped at equal intervals in the depth direction while gradually becoming smaller, and an infinite mirror image is obtained, similar to display device 100 shown in Fig. 1. Note that light source 160 may be provided on the inner wall of case 110 without providing protrusion 111.

[0086] 5A and 5B are diagrams showing examples of experimental results of the display device of the embodiment. Fig. 5A shows a state in which the switchable region 120A of the liquid crystal display unit 120 is switched to a transmissive state and the anti-reflection layer 130 is viewed. Fig. 5B shows a state in which the switchable region 120A of the liquid crystal display unit 120 is switched to a non-transmissive state and the anti-reflection layer 130 is viewed.

[0087] The left half of the experimental display device has the structure of display device 100 (see FIG. 1 ), and the right half has the structure of display device 100B (see FIG. 4B ). That is, the left half of the experimental display device includes partial reflection mirror 150, and the right half includes reflective polarizer 121B.

[0088] 5A, multiple light sources 160 and other internal structures are visible along the left and right edges and the top edge. The left half of the remaining interior is the inner surface of case 110 between total reflection mirror 140 and partial reflection mirror 150, and the right half is the inner surface of case 110 between total reflection mirror 140 and reflective polarizing plate 121B. The black objects along the left and right edges and the top edge are black resin tapes used for fixing.

[0089] As shown in FIG. 5A, an infinite mirror image was obtained in which the reflected virtual images of the multiple light sources 160 and other internal structures were overlapped along the left, right, and top edges at equal intervals in the depth direction, gradually becoming smaller.

[0090] Furthermore, as shown in FIG. 5B, when the switchable region 120A is switched to the opaque state, the left half appears black with nothing reflected, and the right half appears to reflect an image of the front of the anti-reflection layer 130 like a mirror.

[0091] As described above, when the switchable area 120A is switched to the transparent state, the infinity mirror image is displayed as shown in Fig. 5A. When the switchable area 120A is switched to the non-transparent state, the infinity mirror image can be hidden as shown in Fig. 5B.

[0092] Furthermore, as shown in FIG. 5B, when a partial reflection mirror 150 is used, a black display without reflection on the anti-reflection layer 130 is obtained in the non-transmitting state, and when a reflective polarizing plate 121B is used, a display with reflection on the anti-reflection layer 130 is obtained in the non-transmitting state.

[0093] <Effects> The display device 100 includes a liquid crystal display unit 120, a partially transmissive plate provided on the rear side of the liquid crystal display unit 120, a total reflection mirror 140 provided on the opposite side of the liquid crystal display unit 120 from the partially transmissive plate and facing the partially transmissive plate with a gap between them, and a light source 160 (first light source) having a central axis of light emission directed toward the partially transmissive plate or the total reflection mirror 140 and outputting light into the region (space) between the partially transmissive plate and the total reflection mirror 140. Thus, the light output from the light source 160 is repeatedly reflected between the total reflection mirror 140 and the partially transmissive plate, and each time the light is incident on the partially transmissive plate, a portion of the light is transmitted through the partially transmissive plate from the bottom to the top, thereby forming an infinity mirror image. Then, by switching the voltage applied to the liquid crystal layer 126 of the liquid crystal display unit 120, it is possible to switch between a transmissive state in which the infinity mirror image can be displayed and a non-transmissive state in which the infinity mirror image is not displayed.

[0094] Therefore, it is possible to provide the display devices 100 and 100A to 100G that can switch between displaying and hiding the infinite mirror image.

[0095] Furthermore, in the display devices 100 and 100A to 100G, the light source 160 is disposed outside the switchable region 120A in a planar view, so the size of the region outside the switchable region 120A can be set arbitrarily to match the size of the light source 160. Since the light source 160 can be disposed inside the outer edge of the liquid crystal display unit 120 in a planar view, the display devices 100 and 100A to 100G can be made smaller.

[0096] The partially transmitting plate may also be a partially reflecting mirror 150. Depending on the reflectance of the partially reflecting mirror 150, the amount of light that is repeatedly reflected multiple times between the total reflecting mirror 140 and the partially reflecting mirror 150 can be set, and the intensity of the display of the infinite mirror image can be set.

[0097] The liquid crystal display unit 120 may also have a liquid crystal layer 126, a glass plate 124 provided on a first side (+Z direction side) of the liquid crystal layer 126 opposite the partial reflection mirror 150, a glass plate 122 provided on a second side (-Z direction side) of the liquid crystal layer 126 opposite the first side, a pair of electrodes 1 (first electrodes), and a pair of electrodes 2 (second electrodes). The pair of electrodes 1 may be connected to each other so as to have the same potential, and one electrode may be provided on each of the glass plate 124 and the glass plate 122. The pair of electrodes 2 may be connected to each other so as to have the same potential, and one electrode may be provided on each of the glass plate 124 and the glass plate 122. In the central portions of the glass plates 124 and 122 in a planar view, the electrode 1 of the glass plate 124 and the electrode 2 of the glass plate 122 overlap, and in the portions outside the central portions of the glass plates 124 and 122 in a planar view, a pair of electrodes 1 may overlap, and a pair of glass plates 122 may overlap.

[0098] When a voltage is applied to the liquid crystal layer 126, only the switchable region 120A is in a transparent state, allowing an infinite mirror image to be displayed. When no voltage is applied to the liquid crystal layer 126, the entire liquid crystal display unit 120, including the switchable region 120A, is in a non-transparent state, making it possible to hide all images and also to conceal components on the back side (-Z direction side) of the liquid crystal display unit 120. When no voltage is applied to the liquid crystal layer 126, the entire liquid crystal display unit 120 is in a non-transparent state, making it possible to hide all images.

[0099] Furthermore, electrode 1 of glass plate 124 may extend to an end of glass plate 124 in a first direction, and electrode 2 of glass plate 124 may be provided around electrode 1 of glass plate 124. Electrode 2 of glass plate 122 may extend to an end of glass plate 122 in a second direction that intersects with the first direction in a plan view, and electrode 1 of glass plate 122 may be provided around electrode 2 of glass plate 122. Extending electrode 2 of electrode 122A and electrode 1 of electrode 124A to the end of glass plate 122 makes it easier to connect electrode 2 of electrode 122A and electrode 1 of electrode 124A to an AC-DC power supply 10 outside the liquid crystal display unit 120.

[0100] The light source 160 may be provided in a region where the pair of electrodes 122A and 124A overlap in a planar view, or in a region where the pair of electrodes 122A and 124A overlap in a planar view. The region where the pair of electrodes 122A and 124A overlap in a planar view and the region where the pair of electrodes 122A and 124A overlap in a planar view are regions in the liquid crystal display unit 120 that are always opaque, regardless of whether a voltage is applied to the liquid crystal layer 126. By arranging the light source 160 in such a region that is always opaque, a more attractive infinity mirror image can be displayed, and there is no need to provide a component other than the liquid crystal display unit 120 to hide the light source 160, thereby simplifying the configuration.

[0101] Furthermore, light source 160 may be provided on the surface of partial reflection mirror 150 facing the total reflection mirror 140, or on the surface of total reflection mirror 140 facing the partial reflection mirror 150. The central axis of light emission from light source 160 may be inclined with respect to a line perpendicular to the surface of partial reflection mirror 150 facing the total reflection mirror 140 and the surface of total reflection mirror 140 facing the partial reflection mirror 150. Light source 160 can be attached to total reflection mirror 140 or partial reflection mirror 150 without providing a holder for holding light source 160. Furthermore, by having the central axis of light emission from light source 160 inclined with respect to a line parallel to the Z axis, the number of multiple reflections can be increased, thereby generating an infinite mirror image with greater depth.

[0102] The optical system may also have a case 110 (housing) that houses the liquid crystal display unit 120, the partial reflection mirror 150, the light source 160, and the total reflection mirror 140. The light source 160 may be held by a holder provided on the inner surface of the case 110 so that the central axis of light emission from the light source 160 is inclined with respect to a line perpendicular to the surface of the partial reflection mirror 150 facing the total reflection mirror 140 and the surface of the total reflection mirror 140 facing the partial reflection mirror 150. Since the light source 160 can be fixed to the case 110, the light source 160 can be provided in a location separate from the total reflection mirror 140 and the partial reflection mirror 150. Furthermore, since the central axis of light emission from the light source 160 is inclined with respect to a line parallel to the Z axis, the number of multiple reflections is increased, thereby generating an infinite mirror image with greater depth.

[0103] The device may further include a transparent protective plate disposed on the display surface side of the liquid crystal display unit 120. The protective plate may be provided with an opaque blind portion that overlaps the outer edge of the liquid crystal display unit 120, the outer edge of the partial reflection mirror 150, the outer edge of the total reflection mirror 140, and the light source 160 in a plan view. The blind portion provided on the protective plate can hide the outer edges of the liquid crystal display unit 120, the partial reflection mirror 150, and the total reflection mirror 140, and the light source 160. Note that a configuration including the protective plate will be described using Figures 6A, 6B, 7A, and 8A to 8E.

[0104] 6A is a diagram showing an example of a cross-sectional configuration of a display device 100M1 according to a modification of the embodiment. The display device 100M1 includes a case 110, a liquid crystal display unit 120, an anti-reflection layer 130, a protective plate 135, a total reflection mirror 140, a partial reflection mirror 150, a light source 160, a liquid crystal display unit 170, and a backlight 180. The liquid crystal display unit 170 is an example of a first display unit driven by an active matrix driving method. The two liquid crystal display units 120 are examples of second display units driven by a passive driving method.

[0105] 6A has infinity mirror image regions that display infinity mirror images on the −X and +X directions, and an active display region in the center in the X direction. In a plan view, the active display region is located in the center of the entire display region of the display device 100M1, and the infinity mirror image display region is located on the edge of the active display region.

[0106] Here, the configuration in the XZ cross section will be described, but the display device 100M1 may have a similar configuration in the Y direction. The display device 100M1 may also have a similar configuration in the X and Y directions. That is, the display device 100M1 may have an active display area that is arranged in the center in a plan view, and an infinity mirror image area that is arranged to surround the periphery of the active display area.

[0107] The configuration of the infinity mirror image region of the display device 100M1 is similar to that of the display device 100 shown in FIG.

[0108] The protective plate 135 is a transparent glass plate or resin plate. "Transparent" means that light can pass through it. The protective plate 135 has a decorative layer 135A on the side walls of the case 110, the outer edge of the liquid crystal display unit 120, and the underside of a portion corresponding to the boundary between the liquid crystal display unit 120 and the liquid crystal display unit 170. The decorative layer 135A is black and hides the side walls of the case 110, the outer edge of the liquid crystal display unit 120, and the boundary between the liquid crystal display unit 120 and the liquid crystal display unit 170.

[0109] Furthermore, the case 110, the polarizing plate 125, and the anti-reflection layer 130 are common to the two infinite mirror image areas and one active display area.

[0110] Each of the infinite mirror image regions is provided with a liquid crystal display unit 120, an anti-reflection layer 130, a total reflection mirror 140, a partial reflection mirror 150, and a light source 160.

[0111] The active display area is provided with a liquid crystal display unit 170 and a backlight 180. The liquid crystal display unit 170 has a polarizing plate 171, a glass plate 172 on which a TFT (Thin Film Transistor) is formed, a sealing seal 173, a glass plate 174 on which a color filter is formed, a polarizing plate 125, and a liquid crystal layer 175.

[0112] Polarizer 171, glass plate 172, sealing seal 173, glass plate 174, and polarizer 125 are arranged in this order from bottom to top, and liquid crystal layer 175 is sealed in the space surrounded by sealing seal 173, which has a rectangular ring shape in plan view, and glass plates 172 and 174.

[0113] The backlight 180 is an edge-type backlight and is attached below the polarizing plate 171. The backlight 180 has a light guide that guides light output from a light source provided at the end on the -X direction side, +X direction side, -Y direction side, or +Y direction side, in the +Z direction. The backlight 180 illuminates the liquid crystal display unit 170 from the -Z direction side.

[0114] The liquid crystal display unit 170 can display various still images, moving images, and other images in the active display area by driving the TFTs formed on the glass plate 172 in an active matrix manner.

[0115] Therefore, the display device 100M1 can display various images in the active display area, and can also display an infinity mirror image in the infinity mirror image display area.

[0116] As described above for the display device 100M1, the liquid crystal display unit has a first display unit (liquid crystal display unit 170) driven by an active matrix driving method and a second display unit (liquid crystal display unit 120) driven by a passive driving method, and the partial reflection mirror 150 may be provided on the rear side of the second display unit (liquid crystal display unit 120). The active matrix driving method makes it possible to provide a display device 100M1 that can display a variety of still images, videos, and other images, and can switch the infinity mirror image on the second display unit to be displayed or hidden. The light source 160 may be provided on the inner wall of the case 110, without providing the protrusion 111.

[0117] Instead of the liquid crystal display unit 170 and the backlight 180, liquid crystal display units 220, 220D, and 220E of the display devices 200 and 200A to 200E of the second embodiment described below, and backlights 280 and 280A may be used.

[0118] Display Device 100M2 of Modified Example of Embodiment FIG. 6B is a diagram showing an example of a cross-sectional configuration of a display device 100M2 of a modified example of the embodiment.

[0119] The display device 100M2 shown in Fig. 6B differs from the display device 100M1 shown in Fig. 6A in that it has a liquid crystal display unit 120M that integrates the two liquid crystal display units 120 shown in Fig. 6A and one liquid crystal display unit 170. For this reason, only the liquid crystal display unit 120M will be described here.

[0120] 6B has infinity mirror image regions that display infinity mirror images on the −X and +X directions, and an active display region in the center in the X direction. In a plan view, the active display region is located in the center of the entire display region of the display device 100M2, and the infinity mirror image display region is located on the edge of the active display region.

[0121] Here, the configuration in the XZ cross section will be described, but the display device 100M2 may have a similar configuration in the Y direction. The display device 100M2 may also have a similar configuration in the X and Y directions. That is, the display device 100M2 may have an active display area that is arranged in the center in a plan view, and an infinity mirror image area that is arranged to surround the periphery of the active display area.

[0122] The liquid crystal display unit 120M includes a polarizing plate 121M, a glass plate 122M, a sealing seal 123M, a glass plate 124M, a polarizing plate 125M, and a liquid crystal layer 126M. The polarizing plate 121M, the glass plate 122M, the sealing seal 123M, the glass plate 124M, the polarizing plate 125M, and the liquid crystal layer 126M are common to the active display area and the infinity mirror image area.

[0123] The glass plate 122M has a TFT formed in the portion within the active display area, and the glass plate 124M has a color filter provided in the portion within the active display area, and within the active display area, the liquid crystal layer 126M can be driven using an active matrix driving method to display various images.

[0124] Furthermore, the glass plates 122M and 124M have electrodes formed in the portions within the infinity mirror image display area that can realize the switchable region 120A, and the liquid crystal layer 126M within the infinity mirror image display area can be switched between a transmissive state and a non-transmissive state. By switching the liquid crystal layer 126M within the infinity mirror image display area to the transmissive state, an infinity mirror image can be displayed.

[0125] As described above, the liquid crystal display unit 120M has a first display area (active display area) driven by an active matrix driving method and a second display area (infinity mirror image display area) driven by a passive driving method, and the partial reflection mirror 150 may be provided on the rear side of the second display area. The active matrix driving method can provide a display device 100M2 that can display various still images, videos, and other images, and can switch the infinity mirror image on or off in the second display unit. Furthermore, the first display area (active display area) and the second display area (infinity mirror image display area) can be displayed within a single liquid crystal display unit 120M.

[0126] Note that the liquid crystal display units 220, 220D, and 220E of the display devices 200 and 200A to 200E of the second embodiment described below and the backlights 280 and 280A may be used instead of the portion of the liquid crystal display unit 120M within the active display area and the backlight 180. Furthermore, the light source 160 may be provided on the inner wall of the case 110 or the like without providing the protrusion 111.

[0127] 7A is a diagram showing an example of a cross-sectional configuration of a display device 200 according to embodiment 2. The display device 200 includes a case 210, a liquid crystal display unit 220, a protective plate 235, a total reflection sheet 240, a partial reflection sheet 250, a light diffusion sheet 255, a light source 260, a substrate 265, and a backlight 280. The partial reflection sheet 250 is an example of a partial transmission plate and also an example of a partial reflection mirror. The light source 260 is an example of a first light source.

[0128] The case 210 and the light source 260 are similar to the case 110 and the light source 160, respectively, of the display device 100 of the first embodiment (see FIG. 1).

[0129] The protective plate 235 is the same as that of the display device 100M1 (see FIG. 6A ) of the modified embodiment. The total reflection sheet 240 and the partial reflection sheet 250 are obtained by replacing the total reflection mirror 140 and the partial reflection mirror 150 of the display device 100 of the first embodiment (see FIG. 1 ) with sheet-like members. Note that the display device 200 does not include the anti-reflection layer 130 (see FIG. 1 ), but may include one. The upper surface of the protective plate 235 is the display surface of the display device 200.

[0130] The following describes each component of the display device 200 of embodiment 2, focusing on the differences from the display device 100 of embodiment 1. The display device 200 of embodiment 2 is similar to the display device 100 of embodiment 1 in that it is capable of displaying an infinite mirror image.

[0131] <Case 210> Case 210 is the housing of display device 200. For example, case 210 is box-shaped and rectangular in plan view. Case 210 has an opening at the top and an internal space that is connected to the opening and extends downward. Such an internal space is an example of a region, and more specifically, an example of a three-dimensional region. A total reflection sheet 240 is disposed at the bottom of the internal space of case 210, and a protective plate 235 is provided at the opening at the top. Furthermore, the internal space of case 210 may be sealed with, for example, a transparent resin. The portion of the internal space sealed with transparent resin in this manner is a three-dimensional region inside case 210.

[0132] <Liquid Crystal Display Unit 220> The liquid crystal display unit 220 is, for example, adhered to the lower surface of the protection plate 235 by an OCA (Optical Clear Adhesive) 228. Instead of the OCA 228, an OCR (Optical Clear Resin) may be used.

[0133] The liquid crystal display unit 220 has a polarizing plate 221, a glass plate 222, a glass plate 224, and a polarizing plate 225. In Fig. 7A, the sealing seal 123 and the liquid crystal layer 126 shown in Fig. 1 are omitted. The glass plate 224 is an example of a first glass plate, and the glass plate 222 is an example of a second glass plate.

[0134] As an example, the liquid crystal display unit 220 is a liquid crystal display unit driven by an active matrix driving method. For this purpose, TFTs are formed on the upper surface of the glass plate 222, and a color filter is provided on the lower surface of the glass plate 224. The liquid crystal display unit 220 driven by the active matrix driving method can display various images such as still images and moving images. The configuration and operation of the liquid crystal display unit 220 are similar to those of the liquid crystal display unit 170 shown in FIG. 6A, and therefore a detailed description thereof will be omitted.

[0135] The protective plate 235 is a transparent glass plate or resin plate. "Transparent" means that light passes through it. The protective plate 235 has a decorative layer 235A in a plan view at the outer edges of the OCA 228, the liquid crystal display unit 220, the light diffusion sheet 255, and the partial reflection sheet 250, and at the portions where the light source 260 and the substrate 265 are located. The decorative layer 235A is provided on the lower surface of the protective plate 235 and is a black decorative layer that conceals the outer edges of the OCA 228, the liquid crystal display unit 220, the light diffusion sheet 255, and the partial reflection sheet 250, the light source 260, and the substrate 265. The decorative layer 235A has a rectangular ring shape in a plan view, and the inner edge of the decorative layer 235A is located inside the central edge of the substrate 265, which will be described later.

[0136] <Total Reflection Sheet 240> The total reflection sheet 240 is provided at the bottom of the internal space of the case 210, and its upper surface is a reflective surface that totally reflects light. The total reflection sheet 240 is a sheet-like version of the total reflection mirror 140 of embodiment 1, and functions as a total reflection mirror. As an example, the total reflection sheet 240 can be produced by depositing aluminum on the upper surface of a sheet-like member. Note that the total reflection sheet 240 is not limited to this configuration, and may have any configuration as long as it has a reflective surface that totally reflects light as its upper surface. Furthermore, the total reflection mirror 140 of embodiment 1 may be used instead of the total reflection sheet 240.

[0137] <Partial Reflection Sheet 250> The partial reflection sheet 250 is attached to the lower surface of the liquid crystal display unit 220 via a light diffusion sheet 255. The partial reflection sheet 250 is a sheet-like version of the partial reflection mirror 150 of embodiment 1, and functions as a partial reflection mirror. The light transmittance of the partial reflection sheet 250 may be set to an appropriate value between approximately 20% and approximately 80%, for example, and more preferably between approximately 30% and approximately 70%. Here, as an example, the light transmittance of the partial reflection sheet 250 is assumed to be 50%.

[0138] The partially reflective sheet 250 transmits light coming from below from the lower surface to the upper surface, and reflects the remaining light downward from the lower surface.

[0139] Here, instead of the partial reflection sheet 250, the partial reflection mirror 150 of embodiment 1 (see Figure 1) may be used, or the hard coat 150A of the display device 100A of the modified embodiment (see Figure 4A) may be used.

[0140] <Light Diffusion Sheet 255> The light diffusion sheet 255 is a sheet that diffuses incident light, and for example, an LED diffusion sheet can be used. The light diffusion sheet 255 has adhesive properties, for example. Therefore, the partial reflection sheet 250 can be attached to the lower surface of the polarizing plate 221 of the liquid crystal display unit 220 using the light diffusion sheet 255. By providing the light diffusion sheet 255, it is possible to sufficiently scatter light below the liquid crystal display unit 220, and to display an infinite mirror image.

[0141] <Light Source 260> As an example, the light source 260 is mounted on the lower surface of a substrate 265 attached to the lower surface of the partial reflection sheet 250. As an example, the light source 260 is an LED, but it may be an illuminant other than an LED. The light source 260 outputs light to the space (area) between the partial reflection sheet 250 and the total reflection sheet 240.

[0142] Here, the arrangement of the light source 260 will be described using Fig. 7B in addition to Fig. 7A. Fig. 7B is a diagram showing an example of the positional relationship in a plan view between the light sources 260 and 282. Fig. 7B also shows the side wall of the case 210 and the inner edge of the decorative layer 235A.

[0143] A plurality of light sources 260 are provided, and are arranged at equal intervals in a plan view along three of the four side walls of case 210. As an example, the three side walls of case 210 are a side wall on the −X direction side that extends in the Y direction, a side wall on the −Y direction side that extends in the X direction, and a side wall on the +X direction side that extends in the Y direction.

[0144] The central axis of light emission of light source 260 is inclined with respect to a line (a line parallel to the Z axis) perpendicular to the lower surface of partial reflection sheet 250 and the upper surface of total reflection sheet 240. More specifically, as an example, the central axis of light emission of light source 260 is configured to face diagonally downward toward the center of light guide 281 of backlight 280. By inclining the central axis of light emission of light source 260 with respect to a line (a line parallel to the Z axis) perpendicular to the lower surface of partial reflection sheet 250 and the upper surface of total reflection sheet 240, light is incident obliquely on total reflection sheet 240 and partial reflection sheet 250, increasing the number of times of multiple reflection and resulting in an infinite mirror image with greater depth.

[0145] <Substrate 265> The substrate 265 is provided on the lower surface of the partial reflection sheet 250 along the three side walls of the case 210 described above. As an example, the substrate 265 is adhered to the lower surface of the partial reflection sheet 250 with a transparent adhesive such as OCA. When viewed in an X-Z cross section, the width of the substrate 265 in the X direction is wider than that of the light source 260, and both ends in the X direction are located outside of the light source 260. The same is true when viewed in a Y-Z cross section of the section in which the light source 260 is provided along the X direction on the -Y direction side. In other words, the width of the substrate 265 in the Y direction is wider than that of the light source 260, and both ends in the Y direction are located outside of the light source 260.

[0146] As an example, a wiring board such as a PWB (Printed Wiring Board) or an FPC (Flexible Printed Circuit) can be used as the substrate 265. Note that the terminals of each light source 260 are connected to an external device of the display device 200 via wiring or the like of the substrate 265 and further via wiring or the like not shown, and lighting control of each light source 260 is performed, for example, by the external device.

[0147] <Backlight 280> The backlight 280 is an edge-type backlight, and is attached to the upper surface of the total reflection sheet 240. The backlight 280 has a light guide 281 and a plurality of light sources 282. The light sources 282 are an example of a second light source. The backlight 280 is located on the −Z direction side of the light source 260.

[0148] Light guide 281 is provided on almost the entirety of total reflection sheet 240. A light guide pattern 281A that reflects light upward is provided in the central portion of the lower surface of light guide 281, excluding both ends in the X and Y directions. Light guide pattern 281A is, for example, minute irregularities provided on the lower surface of light guide 281, or a film coated with a light-reflecting material.

[0149] As an example, the light source 282 is an LED, but may be a light-emitting element other than an LED. As an example, as shown in FIG. 7B , the multiple light sources 282 are provided near the bottom of one of the four side walls of the case 210 that extends in the X direction on the +Y direction side, facing the -Y direction side. The multiple light sources 282 are also arranged along the side wall that extends in the X direction on the +Y direction side of the case 210, but in a section excluding the end on the -X direction side and the end on the +X direction side. This is to prevent the multiple light sources 282 from overlapping in a plan view with the light source 260 that is arranged at the end on the -Y direction side of the multiple light sources 260 on the -X direction side and the +X direction side.

[0150] The reason why the multiple light sources 282 are provided along the side wall extending in the X direction on the +Y direction side of the case 210 and arranged in a section excluding the end on the -X direction side and the end on the +X direction side is to make the infinity mirror image easier to see by arranging them in positions that do not overlap with the multiple light sources 260 in a planar view. Note that the light sources 282 of the backlight 280 may be arranged in positions that overlap with the light sources 260 in a planar view if the display of the infinity mirror image is not affected.

[0151] In such a display device 200, when the light source 260 and the light source 282 of the backlight 280 are turned on and the liquid crystal display unit 220 displays an image, the image of the liquid crystal display unit 220 is displayed in the rectangular display area surrounded by the decorative layer 235A of the protective plate 235.

[0152] Furthermore, because the central axis of light emission of light source 260 is inclined with respect to a line (a line parallel to the Z axis) perpendicular to partial reflection sheet 250 and total reflection sheet 240, light is incident obliquely on total reflection sheet 240 and partial reflection sheet 250. As a result, the number of multiple reflections between total reflection sheet 240 and partial reflection sheet 250 increases, and an infinite mirror image is displayed at the ends of the −X direction, −Y direction, and +X direction of the rectangular display area surrounded by decorative layer 235A of protective plate 235. The ends of the −X direction, −Y direction, and +X direction of the rectangular display area surrounded by decorative layer 235A are located at positions corresponding to the three side walls of case 210 on which multiple light sources 260 are provided.

[0153] As described above, the display device 200 of embodiment 2 can display an infinity mirror image. More specifically, the display device 200 of embodiment 2 can display an image of the liquid crystal display unit 220 in the center of a rectangular display area surrounded by the decorative layer 235A of the protective plate 235, and can also display an infinity mirror image around the central area.

[0154] <Display Devices 200A to 200E as Modifications of Embodiment 2> Figures 8A to 8E are cross-sectional views showing examples of the configuration of display devices 200A to 200E as modification examples of Embodiment 2. Figures 8A to 8E show cross-sectional configurations taken along the XZ plane, which corresponds to the display device 200 shown in Figure 7A. Furthermore, the same components as those of the display device 200 shown in Figure 7A are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0155] <Display Device 200A> Display device 200A shown in FIG. 8A has a configuration in which light diffusion sheet 255 of display device 200 shown in FIG. 7A is omitted, and a backlight 280A is included instead of backlight 280 shown in FIG. 7A.

[0156] The light-transmitting material of the light guide 281 of the backlight 280A contains, for example, nanoparticles (nano-scattering materials), and thus has a light-scattering function. Therefore, the display device 200A can sufficiently scatter light below the liquid crystal display unit 220 even without the light diffusion sheet 255, and can display an infinite mirror image similar to the display device 200 shown in FIG. 7A.

[0157] <Display device 200B> The display device 200B shown in FIG. 8B has a configuration in which the light source 260 and the substrate 265 of the display device 200 shown in FIG. 7A are moved to the upper surface of the light guide 281 of the backlight 280, and the light source 260 is arranged facing upward.

[0158] The central axis of light emission of light source 260 of display device 200B is directed obliquely upward so as to face the center of partial reflection sheet 250. In other words, the central axis of light emission of light source 260 is inclined with respect to a line (a line parallel to the Z axis) perpendicular to the lower surface of partial reflection sheet 250 and the upper surface of total reflection sheet 240. This is because light is incident obliquely on total reflection sheet 240 and partial reflection sheet 250, which increases the number of multiple reflections and results in an infinite mirror image with greater depth.

[0159] The display device 200B has a configuration in which the light source 260 and the substrate 265 are disposed on the upper surface of the light guide 281, and is therefore capable of displaying an infinite mirror image in the same manner as the display device 200 shown in FIG. 7A.

[0160] 8B has a configuration in which the light source 260 and the substrate 265 of the display device 200 shown in Fig. 7A are moved to the upper surface of the light guide 281 of the backlight 280, and the light source 260 is arranged facing upward. For example, the substrate 265 may be bonded to the upper surface of the light guide 281 with a transparent adhesive such as OCA.

[0161] The central axis of light emission of light source 260 of display device 200B is directed obliquely upward so as to face the center of partial reflection sheet 250. In other words, the central axis of light emission of light source 260 is inclined with respect to a line (a line parallel to the Z axis) perpendicular to the lower surface of partial reflection sheet 250 and the upper surface of total reflection sheet 240. This is because light is incident obliquely on total reflection sheet 240 and partial reflection sheet 250, which increases the number of multiple reflections and results in an infinite mirror image with greater depth.

[0162] The display device 200B has a configuration in which the light source 260 and the substrate 265 are disposed on the upper surface of the light guide 281, and is therefore capable of displaying an infinite mirror image in the same manner as the display device 200 shown in FIG. 7A.

[0163] 8C has a configuration in which the light source 260 and the substrate 265 of the display device 200 shown in Fig. 7A are moved to the inner surface of the side wall of the case 210. For example, the substrate 265 may be adhered to the side wall of the case 210 with a transparent adhesive such as OCA.

[0164] The central axis of light emission of the light source 260 of the display device 200C may be inclined with respect to a line (a line parallel to the Z axis) perpendicular to the lower surface of the partial reflection sheet 250 and the upper surface of the total reflection sheet 240, as in the display device 100 of the first embodiment (see FIG. 1). This is because light is incident obliquely on the total reflection sheet 240 and the partial reflection sheet 250, the number of multiple reflections increases, and an infinite mirror image with greater depth is obtained.

[0165] For example, the central axis of light emission of light source 260 has an angle of approximately 70 degrees in absolute value with respect to a line (a line parallel to the Z axis) perpendicular to partial reflection sheet 250 and total reflection sheet 240. In other words, for example, the central axis of light emission of light source 260 has an angle of approximately 20 degrees upward or downward with respect to the horizontal direction. Furthermore, the light output from each light source 260 propagates radially over a wide range so that the light directly reaches total reflection sheet 240 on the lower side and the light directly reaches partial reflection sheet 250 on the upper side.

[0166] The display device 200C is configured such that the light source 260 and the substrate 265 are disposed on the inner surface of the side wall of the case 210, and is therefore capable of displaying an infinite mirror image, similar to the display device 200 shown in FIG. 7A. Furthermore, since the light source 260 and the substrate 265 are disposed on the inner surface of the side wall of the case 210, the distance in the Z direction between the total reflection sheet 240 and the partial reflection sheet 250 can be shortened. Therefore, the display device 200C can be made thinner than the display device 200 (see FIG. 7A), the display device 200A (see FIG. 8A), and the display device 200B (see FIG. 8B).

[0167] <Display Device 200D> The display device 200D shown in FIG. 8D has a configuration in which the liquid crystal display unit 220 of the display device 200 shown in FIG. 7A is replaced with a liquid crystal display unit 220D.

[0168] The liquid crystal display unit 220D has a content display area 220D1, a gradation display area 220D2, and a black display area 220D3, which are arranged from the center to the outer edge of the liquid crystal display unit 220D in a planar view. In a planar view, the content display area 220D1 is rectangular, the gradation display area 220D2 is a rectangular ring-shaped area surrounding the content display area 220D1, and the black display area 220D3 is a rectangular ring-shaped area surrounding the gradation display area 220D2 and the content display area 220D1.

[0169] As an example, the liquid crystal display unit 220D of the display device 200D has a relatively low brightness, which makes it difficult to see the components located inside the case 210 relative to the protective plate 235, and therefore makes it difficult to see the light source 260 and the substrate 265 from the display surface of the display device 200D. For this reason, the light source 260 and the substrate 265 may be located inside the inner edge of the decorative layer 235A; in other words, the inner edge of the decorative layer 235A may be located further outward. The fact that the inner edge of the decorative layer 235A may be located further outward means that the width between the inner edge and outer edge of the decorative layer 235A may be narrowed.

[0170] Note that, even when the contrast of the liquid crystal display unit 220D is relatively high, as in the case where the brightness is relatively low, it is difficult to see the components located inside the case 210 relative to the protective plate 235, and it is difficult to see the light source 260 and the substrate 265 from the display surface of the display device 200D. For this reason, even when the contrast of the liquid crystal display unit 220D is relatively high, the inner edge of the decorative layer 235A may be positioned further outward, or the width between the inner edge and outer edge of the decorative layer 235A may be narrowed.

[0171] The content display area 220D1 is an area where various still images, moving images, and other images can be displayed by driving the TFTs provided on the upper surface of the glass plate 222 using an active matrix driving method.

[0172] The gradation display area 220D2 is an area in which the gradation increases in stages from the inside near the content display area 220D1 to the outside near the black display area 220D3. This type of gradation control is called stepped gradation control. Because the gradation display area 220D2 is an area in which the infinity mirror image is displayed, stepped gradation control is used to display the infinity mirror image more clearly.

[0173] The black display region 220D3 is provided so as to overlap the inner edge of the decorative layer 235A in plan view. In other words, the inner edge of the decorative layer 235A is located inside the rectangular ring-shaped black display region 220D3 in plan view.

[0174] The black display region 220D3 is a region in which the liquid crystal display unit 220 is displayed in black. When the display device 200D is viewed from the display surface side, the black display region 220D3 displays black as if it were an extension of the black decorative layer 235A inward. The black display region 220D3 also hides the substrate 265 and other components located inside the inner edge of the decorative layer 235A in a plan view. In this way, the black display region 220D3 displays black as if it were an extension of the decorative layer 235A inward, thereby hiding the substrate 265 and other components while achieving a sense of unity with the decorative layer 235A.

[0175] The display device 200D displays various images, such as still images and videos, in the content display area 220D1, while increasing the gradation of the surrounding gradation display area 220D2, thereby enabling the infinity mirror image to be displayed clearly. In other words, the display device 200D can clearly display both various images, such as still images and videos, and the infinity mirror image.

[0176] The display device 200D is also suitable when the brightness of the liquid crystal display section 220D is relatively low or when the contrast is relatively high.

[0177] <Display Device 200E> A display device 200E shown in FIG. 8E has a configuration in which the liquid crystal display unit 220 of the display device 200 shown in FIG. 7A is replaced with a liquid crystal display unit 220E.

[0178] The liquid crystal display unit 220E has a content display area 220E1, a gradation display area 220E2, and a black display area 220E3 extending from the center to the outer edge of the liquid crystal display unit 220E in a planar view. The content display area 220E1, the gradation display area 220E2, and the black display area 220E3 differ in size in a planar view from the content display area 220D1, the gradation display area 220D2, and the black display area 220D3 shown in Fig. 8D but have the same shape and arrangement.

[0179] The display device 200E shown in Fig. 8E has the inner edge of the decorative layer 235A positioned further inward than the display device 200D shown in Fig. 8D. That is, the width between the inner edge and outer edge of the rectangular annular decorative layer 235A of the display device 200E shown in Fig. 8E is wider than the width between the inner edge and outer edge of the decorative layer 235A of the display device 200D shown in Fig. 8D.

[0180] As an example, the liquid crystal display unit 220E of the display device 200E has a relatively high brightness, which makes it easier to see the components inside the case 210 than the protective plate 235, and makes it easier to see the light source 260 and the substrate 265 from the display surface of the display device 200E. For this reason, if the light source 260 or the substrate 265 is positioned inside the inner edge of the decorative layer 235A, there is a risk that they will be visible, and therefore it is preferable to position the inner edge of the decorative layer 235A further inward.

[0181] Even when the contrast of the liquid crystal display unit 220E is relatively low, the components inside the case 210 are more easily visible than the protective plate 235, and the light source 260 and the substrate 265 are more easily visible from the display surface of the display device 200E, just as when the brightness is relatively high. For this reason, even when the contrast of the liquid crystal display unit 220E is relatively low, it is preferable to position the inner edge of the decorative layer 235A more inward. For this reason, the width between the inner edge and outer edge of the rectangular annular decorative layer 235A of the display device 200E is wider than the width between the inner edge and outer edge of the decorative layer 235A of the display device 200D shown in FIG. 8D .

[0182] The roles of the content display area 220E1, the gradation display area 220E2, and the black display area 220E3 are similar to those of the content display area 220D1, the gradation display area 220D2, and the black display area 220D3 shown in Fig. 8D. However, due to differences in the width of the decorative layer 235A, the content display area 220E1, the gradation display area 220E2, and the black display area 220E3 are configured as follows.

[0183] Like content display area 220D1, content display area 220E1 is capable of displaying various still images, moving images, and other images using an active matrix driving method, but is slightly smaller than content display area 220D1.

[0184] The gradation display area 220E2, like the gradation display area 220D2, is an area that clearly displays an infinity mirror image by performing step gradation control, but the outer edge of the gradation display area 220E2 roughly coincides with the inner edge of the decorative layer 235A. In the step gradation control, it is preferable to control the gradation so that the change in value is as continuous as possible and the gradation changes smoothly.

[0185] The black display region 220E3 displays black like the black display region 220D3, but is provided at a position overlapping the decorative layer 235A.

[0186] Since the LCD display unit 220E has high brightness or low contrast, making components such as the light source 260 and the substrate 265 inside the case 210 easily visible, the positions of the gradation display area 220E2 and the black display area 220E3 and the width of the decorative layer 235A are adjusted as described above, for example, to ensure that these components are hidden.

[0187] In this example, the width of the decorative layer 235A is increased to allow the black display region 220E3 and the decorative layer 235A to overlap in order to hide the internal components. However, the positions of the gradation display region 220E2 and the black display region 220E3 and the width of the decorative layer 235A may be adjusted depending on the relationship between the gradation of the gradation display region 220E2, the gradation of the black of the black display region 220E3, the visibility of the internal components, and the like.

[0188] The display device 200E displays various images, such as still images and videos, in the content display area 220E1, while increasing the gradation of the surrounding gradation display area 220E2, thereby enabling the infinity mirror image to be displayed clearly. In other words, the display device 200E can clearly display both various images, such as still images and videos, and the infinity mirror image.

[0189] The display device 200E is also suitable when the brightness of the liquid crystal display section 220E is relatively high or the contrast is relatively low.

[0190] 9A and 9B are diagrams showing an example of measurement of gradation control in the display device 200D. 9A and 9B show the display state in the display area (inside the inner edge of the decorative layer 235A) of the protective plate 235 of the display device 200D. The gradation of the liquid crystal display unit 220D can be controlled in 256 gradations for each of RGB, for example, with the brightest (lightest) gradation being L255 and the darkest (darkest) gradation being L0.

[0191] 9A and 9B, the content display area 220D1 is indicated by a dashed line, the gradation display area 220D2 is indicated by a dashed line, and the black display area 220D3 is indicated by a two-dot chain line.

[0192] In Figures 9A and 9B, an image with the word "Welcome" placed in the center of a black background is displayed on the liquid crystal display unit 220, and the gradation of the content display area 220D1, gradation display area 220D2, and black display area 220D3 is set as follows.

[0193] 9A shows a state in which the light source 260 is turned on (lit), the backlight 280 is turned on (lit), and the gradation of the background image in the content display area 220D1 is set to L7 (eighth from L0). Also, in FIG. 9A, the gradation of the gradation display area 220D2 is set to L7 at the inner edge and L255 at the outer edge using stepped gradation control. The gradation of the black display area 220D3 is set to L0 (black).

[0194] 9B shows a state in which the light source 260 is turned off (exited), the backlight 280 is turned on (lit), and the gradation of the image in the content display area 220D1 is set to L7 (eighth from L0). Also, in FIG. 9B, the gradation in the gradation display area 220D2 is set to L7 without performing step gradation control. The gradation in the black display area 220D3 is set to L0 (black).

[0195] 9A and 9B, it can be seen that by performing stepped gradation control in the content display area 220D1 (see FIG. 9A), it is possible to display the infinity mirror image more clearly than when stepped gradation control is not performed (see FIG. 9B). It was also confirmed that the infinity mirror image can be displayed similarly clearly even when the gradation of the image in the content display area 220D1 is set to L7, the innermost gradation of the gradation display area 220D2 is set to L7, and the outermost gradation of the gradation display area 220D2 is set to L0.

[0196] <Effects> Display device 200 includes a liquid crystal display unit 220, a partial transmission plate (partial reflection sheet 250) provided on the back side of liquid crystal display unit 220, and a total reflection mirror (total reflection sheet 240) provided on the opposite side of liquid crystal display unit 220 from the partial transmission plate, with a gap between the partial transmission plate and the total reflection mirror, and facing the partial transmission plate. Display device 200 also includes an edge-type backlight (backlight 280) that has a central axis of light emission directed toward the partial transmission plate or the total reflection mirror and includes a first light source (light source 260) that outputs light to a region (space) between the partial transmission plate and the total reflection mirror, a second light source (light source 282), and a light guide 281 that guides the light output from the second light source, and is provided closer to the total reflection mirror than light source 260. As a result, multiple reflections of a reflected virtual image are obtained between the partial transmission plate and the total reflection mirror, allowing an infinite mirror image to be displayed.

[0197] Therefore, it is possible to provide a display device 200 that can display an infinite mirror image.

[0198] The partially transmitting plate may also be a partially reflecting mirror (partially reflecting sheet 250). Depending on the reflectance of the partially reflecting mirror (partially reflecting sheet 250), the amount of light that is repeatedly reflected multiple times between the total reflecting mirror and the partial reflecting mirror (partially reflecting sheet 250) can be set, and the intensity of the infinite mirror image can be set.

[0199] The liquid crystal display unit 220 also has a gradation display area 220D2 that displays a gradation image, and light output from the light source 260 may be incident on the gradation display area 220D2. When the light from the light source 260 is incident on the gradation display area 220D2, an infinite mirror image can be displayed in the gradation display area 220D2.

[0200] Furthermore, the light-transmitting material of the light guide 281 may contain a nano-scattering material, or the back surface of the light guide 281 may have minute irregularities. By using a backlight 280A having a light guide 281 containing a nano-scattering material or a backlight 280 having a light guide pattern 281A, the light of the backlight 280 can be scattered, making it possible to display a clearer infinite mirror image.

[0201] The liquid crystal display unit 220 may be driven by an active matrix driving method, and the display device 200 can display various still images, moving images, and the like, as well as displaying an infinite mirror image around the images.

[0202] The above describes a display device according to an exemplary embodiment of the present disclosure, but the present disclosure is not limited to the specifically disclosed embodiment, and various modifications and changes are possible without departing from the scope of the claims.

[0203] This international application claims priority based on Japanese Patent Application No. 2023-114745, filed on July 12, 2023, the entire contents of which are incorporated herein by reference.

[0204] 100, 100A to 100G, 100M1, 100M2 Display device 110 Case (an example of a housing) 111 Convex portion 120, 120B, 120M Liquid crystal display unit 121, 121M Polarizing plate 121B Reflective polarizing plate (an example of a partially transmitting plate) 122 Glass plate (an example of a second glass plate) 122A Electrode 1 Electrode (electrode 1 of electrode 122A) (an example of a first electrode) 2 Electrode (electrode 2 of electrode 122A) (an example of a second electrode) 123, 123M Sealing seal 124, 124M Glass plate (an example of a first glass plate) 124A Electrode 1 Electrode (electrode 1 of electrode 124A) (an example of a first electrode) 2 Electrode (electrode 2 of electrode 124A) (an example of a second electrode) 125, 125M Polarizing plate 126, 126M Liquid crystal layer 130 Anti-reflection layer 135A Decorative layer 140 Total reflection mirror 150 Partial reflection mirror (an example of a partially transmitting plate) 150A Hard coat (an example of a partially transmitting plate) 160 Light source 170 Liquid crystal display unit 171 Polarizing plate 172 Glass plate 173 Sealing seal 174 Glass plate 175 Liquid crystal layer 180 Backlight 200 Display device 210 Case (an example of a housing) 220, 220M Liquid crystal display unit 220D1, 220E1 Content display area 220D2, 220E2 Gradation display area 220D3, 220E3 Black display area 235 Protective plate 235A Decorative layer 240 Total reflection sheet 250 Partial reflection sheet 255 Light diffusion sheet 260 Light source (an example of a first light source) 265 Substrate 280 Backlight (an example of an edge-type backlight) 281 Light guide body 281A Light guide pattern 282 Light source

Claims

1. LCD display unit, A partially transparent plate provided on the back side of the liquid crystal display unit, A totally reflective mirror is provided on the side of the partial transparent plate opposite to the liquid crystal display unit, with a gap between it and the partial transparent plate, and facing the partial transparent plate. A light source having a central axis of light emission directed toward the partial transparent plate or the total reflection mirror, and outputting light in the region between the partial transparent plate and the total reflection mirror. A display device, including a display device.

2. The display device according to claim 1, wherein the partially transparent plate is a partially reflective mirror.

3. The aforementioned liquid crystal display unit is The liquid crystal layer, A first glass plate is provided on the first side opposite to the partial reflection mirror with respect to the liquid crystal layer, A second glass plate is provided on the second side opposite to the first side with respect to the liquid crystal layer, A pair of first electrodes, A pair of second electrodes, It has, The pair of first electrodes are connected to each other so as to be at the same potential, and one is provided on each of the first and second glass plates. The pair of second electrodes are connected to each other so as to be at the same potential, and one is provided on each of the first and second glass plates. In a plan view, the first electrode of the first glass plate and the second electrode of the second glass plate overlap at the central portion of the first and second glass plates. The display device according to claim 2, wherein in a plan view, the pair of first electrodes and the pair of second glass plates overlap in the portions of the first and second glass plates that are outside the central portion.

4. The first electrode of the first glass plate extends to the end of the first glass plate in the first direction, The second electrode of the first glass plate is provided around the first electrode of the first glass plate, The second electrode of the second glass plate extends to the end in a second direction that intersects with the first direction of the second glass plate in a plan view, The display device according to claim 3, wherein the first electrode of the second glass plate is provided around the second electrode of the second glass plate.

5. The display device according to claim 3 or 4, wherein the light source is provided within a region where the pair of first electrodes overlap in a plan view, or within a region where the pair of second electrodes overlap in a plan view.

6. The light source is provided on the surface of the partial reflection mirror on the total reflection mirror side, or on the surface of the total reflection mirror on the partial reflection mirror side. The display device according to claim 2, wherein the central axis of light emission of the light source is inclined with respect to a straight line perpendicular to the surface of the partial reflection mirror on the total reflection mirror side and the surface of the total reflection mirror on the partial reflection mirror side.

7. The housing comprises the liquid crystal display unit, the partially reflective mirror, the light source, and the totally reflective mirror. The display device according to claim 2, wherein the light source is held by a holding portion provided on the inner surface of the housing such that the central axis of light emission of the light source is inclined with respect to a straight line perpendicular to the surface of the partial reflection mirror on the total reflection mirror side and the surface of the total reflection mirror on the partial reflection mirror side.

8. The aforementioned liquid crystal display unit further includes a transparent protective plate disposed on the display surface side, The display device according to claim 6 or 7, wherein the protective plate is provided with an opaque covering portion that overlaps with the outer edge of the liquid crystal display portion, the outer edge of the partial reflection mirror, the outer edge of the total reflection mirror, and the light source in a plan view.

9. The aforementioned liquid crystal display unit is A first display unit driven by an active matrix drive system, The second display unit is driven by a passive drive system and It has, The display device according to claim 2, wherein the partial reflective mirror is provided on the back side of the second display unit.

10. The aforementioned liquid crystal display unit is A first display area driven by an active matrix drive system, The second display area is driven by a passive drive system and It has, The display device according to claim 2, wherein the partial reflection mirror is provided on the back side of the second display area.