WO2012137762A1 - Display device and electronic apparatus provided with display device - Google Patents

Abstract

A light guide element (300A) mounted to a liquid crystal display device (100A) that is one embodiment of the present invention has a plurality of light guide sections (310). Also, each light guide section (310) is provided with: a transparent section comprising a transparent layer (324); and a reflective section comprising a metal layer (321). In the liquid crystal display device (100A), a polarizing plate is disposed in a manner so that, in a plan view (in other words, when looking at the liquid crystal display device (100A) from above), the direction of the border surface (303) of the light guide element (300A) and the direction (arrow α in the figure) of the light transmission axis of the polarizing plate are parallel to each other. Consequently, the direction of extension of the border surface (303) in the planar direction and the direction of the light transmission axis of the polarizing plate match.

Description

Display device and electronic apparatus including the display device

The present invention relates to a display device capable of reducing a decrease in transmittance of a light guide element, and an electronic apparatus including the display device.

In recent years, there has been an increasing demand for larger display screens. However, there are many technical limitations in increasing the size of a display device, and it takes time to develop a large display device. For this reason, in order to meet the demand for a larger display device, for example, a plurality of display panels are tiled (tiled), and the display screens are simulated by joining the display screens together. Attempts have been made to achieve this.

However, the display panel has a display area composed of a plurality of pixels and a frame area formed outside the display area. The frame region is provided with a seal portion for sealing and holding a display medium (electro-optical element) such as a liquid crystal material, a drive circuit mounting portion for driving the pixels, and the like, and does not contribute to display. .

For this reason, there is a problem that when a tiling technique for tiling a plurality of display panels and joining the display screens is used, a joint between the plurality of display panels can be seen. Note that such a problem occurs in a direct-view display device regardless of the display method (display medium) such as a liquid crystal display device (LCD), a plasma display device (PDP), and an organic electroluminescence (EL) display device. It is a common problem. Therefore, in recent years, in a tiling technique, a display device provided with a light guide element on a display surface has been proposed in order to make it difficult to see the joint, to make it difficult to see the frame area in the display panel and to enlarge the display area. Proposed.

For example, Patent Document 1 discloses a liquid crystal display device that has an optical fiber face plate that covers the entire surface of the display panel and guides part of light emitted from the display area to the frame area by the optical fiber face plate. ing. Patent Document 2 discloses a display unit and a composite type in which an optical fiber face plate composite is provided on the entire surface of the display panel, and the light emitted from the display area is enlarged and displayed on the outer size of the display panel by the optical fiber face plate. A display is disclosed.

Further, Patent Document 3 has light compensation means comprising a large number of inclined thin films and a transparent body filled between the inclined thin films over almost the entire surface of the display panel. A display device is disclosed in which the light is guided to the frame region by light compensation means. Further, Patent Document 4 discloses a display device in which a diffusion member including a large number of optical fibers is disposed only in a region near the frame region, and light emitted from the display region is guided to the frame region by the optical fiber. Is disclosed. By the techniques disclosed in these patent documents 1 to 4, seamless display can be realized.

Japanese Patent Publication “Japanese Patent Laid-Open No. 7-128652 (published May 19, 1995)” Japanese Patent Publication “Japanese Patent Laid-Open No. 2000-56713 (published on February 25, 2000)” Japanese Patent Publication “Japanese Patent Laid-Open No. 2001-5414 (published on January 12, 2001)” US Pat. No. 5,129,028 (registered July 7, 1992)

However, the light guide element generally includes a metal layer and a transmission layer, and light incident on the metal layer is guided while being reflected many times in the metal layer. The loss greatly affects the transmittance of the light guide element. Hereinafter, a decrease in the transmittance of the light guide element will be described in detail with reference to FIG. FIG. 16 is a cross-sectional view schematically showing a configuration of a main part of a liquid crystal display device including a conventional light guide element.

As shown in FIG. 16, when light from the backlight 400A enters the liquid crystal display device 100 ', the light enters the light guide element 300' through the liquid crystal panel 200 '. Here, the light guide element 300 ′ has a plurality of light guide portions, and each light guide portion includes a metal layer and a transmission layer. The light guide element 300 ′ has a structure in which each light guide is inclined with respect to the light incident surface 301 and the light emitting surface 302.

Therefore, the light incident perpendicularly to the incident surface 301 of the light guide element 300 'is emitted from the emission surface 302 by repeating reflection in the light guide (arrow R in the figure). Here, it is assumed that the light guide element 300 ′ has an inclination angle θ of 45 degrees, a stacking pitch p of the light guide parts of 0.1 mm, and a thickness d of the light guide element 300 ′ of 1 mm. . For example, assuming that the transmittance T of the light guide per thickness d is 100% and the reflectance R of the metal layer is 98% (silver), the transmittance of the light guide element 300 ′ is approximately 67%. Become. On the other hand, assuming that the transmittance T is 100% and the reflectance R of the metal layer is 90% (aluminum layer), the transmittance of the light guide element 300 ′ is approximately 13%, and there is a large difference in the transmittance. Arise.

As described above, the loss of light amount due to the light reflection in the metal layer of the light guide portion leads to a large decrease in the transmittance of the light guide element 300 '. If the transmittance of the light guide element 300 ′ is low, it is necessary to compensate for a decrease in the luminance of the liquid crystal display device 100 ′ by increasing the luminance of the backlight device 400. As a result, there is a problem that the power consumption of the liquid crystal display device 100 ′ increases.

Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a display device capable of reducing a decrease in transmittance of a light guide element, and an electronic apparatus including the display device. There is.

In addition, a display device according to one embodiment of the present invention is a display device including a display panel and a light guide element provided on a display surface side of the display panel in order to solve the above problem. The light guide element is configured by repeatedly laminating a reflective layer made of metal and a translucent layer in parallel with each other, and includes a polarizing plate on the display surface side of the display panel, and the reflective layer and the translucent layer. The direction in which the boundary surface with the optical layer extends in the plane direction of the display surface and the direction of the light transmission axis of the polarizing plate are parallel to each other.

According to the above configuration, the boundary surface between the light transmissive layer and the reflective layer is aligned with the direction in which the surface of the display surface extends and the direction of the light transmission axis of the polarizing plate. Since S-polarized light is incident, it is possible to suppress a decrease in reflectance in the reflective layer. That is, a decrease in the reflectance in the reflective layer is suppressed, and the light utilization efficiency can be increased. As a result, the transmittance of the light guide element is improved. Therefore, since the transmittance of the light guide element is low, it is not necessary to compensate for the decrease in luminance of the display device by increasing the luminance of the backlight, thereby eliminating the problem of increasing the power consumption of the display device. be able to.

In order to solve the above problems, an electronic device according to one embodiment of the present invention includes a plurality of any of the display devices described above, and the plurality of display devices are arranged side by side on the same plane. It is characterized by that.

According to the above configuration, since display can be performed without any image shift between display devices adjacent to each other, it is possible to make it difficult to see the region at the boundary portion of each display device.

Other objects, features, and superior points of the present invention will be fully understood from the following description. The advantages of the present invention will become apparent from the following description with reference to the accompanying drawings.

In the display device according to one embodiment of the present invention, the direction in which the boundary surface between the light-transmitting layer and the reflective layer extends in the surface direction of the display surface matches the direction of the light transmission axis of the polarizing plate, Since S-polarized light is incident on the light guide element, it is possible to suppress a decrease in reflectance in the reflective layer. That is, a decrease in the reflectance in the reflective layer is suppressed, and the light utilization efficiency can be increased. As a result, the transmittance of the light guide element is improved. Therefore, since the transmittance of the light guide element is low, it is not necessary to compensate for the decrease in luminance of the display device by increasing the luminance of the backlight, thereby eliminating the problem of increasing the power consumption of the display device. be able to.

(A) in a figure is a top view which shows the liquid crystal display device which concerns on one Embodiment of this invention, (b) in a figure is a boundary surface in the liquid crystal display device shown in (a) in the figure It is sectional drawing which shows an inclination direction. (A) in a figure is a top view which shows the liquid crystal display device which concerns on one Embodiment of this invention, (b) in a figure is a boundary surface in the liquid crystal display device shown in (a) in the figure It is sectional drawing which shows an inclination direction. (A) to (c) in the figure are schematic configuration diagrams showing an example of an external appearance of an electronic apparatus according to an embodiment of the present invention. (A) in a figure is a top view which shows schematic structure of the principal part of the liquid crystal display device based on one Embodiment of this invention, (b) in a figure is the liquid crystal shown to (a) in a figure It is AA arrow directional cross-sectional view of a display apparatus. (A) in a figure is the inclination direction of the boundary line of the light guide parts adjacent in the output surface of each light guide element, when the liquid crystal display device which concerns on one Embodiment of this invention is arrange | positioned adjacent to a horizontal direction. Is a plan view showing the relationship between the image displayed on each liquid crystal panel when the light guide element and the light guide element are line-symmetric, the image actually visible through the light guide element, and the boundary surface of the light guide unit (B) in the figure is a cross-sectional view showing the inclination direction of the boundary surface of the light guide section in the liquid crystal display device shown in (a) in the figure. It is sectional drawing which shows the light guide element which concerns on one Embodiment of this invention. It is sectional drawing which shows an example of the structure of the sheet | seat laminated body used for the light guide element which concerns on one Embodiment of this invention. (A)-(c) in the figure is a diagram showing a method of manufacturing a light guide element using the sheet laminate shown in FIG. 7 in the order of steps. It is a figure which shows roughly the incident light to a metal layer. It is a figure which shows the angle characteristic of the polarization | polarized-light reflectance of a metal layer. It is sectional drawing which shows the light guide element produced as a comparative example of this invention. (A) in a figure is a top view which shows the liquid crystal display device produced as a comparative example of this invention, (b) in the figure is the inclination of the boundary surface in the liquid crystal display device shown in (a) in the figure It is sectional drawing which shows a direction. It is a figure which shows the result of having measured the brightness | luminance from the normal line direction of the liquid crystal display device produced as a comparative example of this invention. (A) in a figure is a top view which shows the liquid crystal display device which concerns on one Embodiment of this invention, (b) in a figure is a boundary surface in the liquid crystal display device shown in (a) in the figure It is sectional drawing which shows an inclination direction. (A) in a figure is a top view which shows the liquid crystal display device which concerns on one Embodiment of this invention, (b) in a figure is a boundary surface in the liquid crystal display device shown in (a) in the figure It is sectional drawing which shows an inclination direction. It is sectional drawing which shows schematically the structure of the principal part of a liquid crystal display device provided with the conventional light guide element.

Hereinafter, embodiments of the present invention will be described in detail.

[Embodiment 1]
An embodiment of the present invention will be described below with reference to the drawings. Examples of electronic devices provided with the display device according to this embodiment include various electronic devices having a display unit such as a mobile phone, an electronic book, a game machine, a TV (television), or a public bulletin board for outdoor use. Can be mentioned. In the following description, an electronic book, a game machine, and a mobile phone will be described as an example of an electronic device including the display device according to this embodiment, but this embodiment is not limited thereto. It is not something. Similarly, in the following description, a liquid crystal display device will be described as an example of the display device according to the present embodiment, but the present embodiment is not limited to this.

(Overview of electronic equipment with display device)
(A) to (c) in FIG. 3 are schematic configuration diagrams showing an example of the external appearance of an electronic apparatus provided with the display device according to the present embodiment. The electronic devices shown in FIGS. 3A to 3C are foldable devices having two display portions. Examples of such an electronic device 1 include an electronic book, a game machine, and a mobile phone as described above, but the present embodiment is not limited to this.

As shown in FIGS. 3A to 3C, the electronic apparatus 1 includes two liquid crystal display devices 100A and 100B provided adjacent to each other as a first display unit and a second display unit. I have. The electronic device 1 is a tiling type device in which two liquid crystal display devices 100A and 100B are arranged (tiled) in a tile shape. In this way, a large screen can be displayed by tiling a plurality of liquid crystal display devices. Tiling can be performed by a known method. Further, in the following description, the case where the electronic apparatus 1 includes two liquid crystal display devices 100A and 100B will be described as an example. However, the number of liquid crystal display devices is not particularly limited, and one or There may be three or more.

The liquid crystal display device 100A includes a liquid crystal panel 200A (display panel) and a light guide element 300A provided on the liquid crystal panel 200A. Similarly, the liquid crystal display device 100B includes a liquid crystal panel 200B (display panel) and a light guide element 300B provided on the liquid crystal panel 200B. The light guide element 300A may be provided on the entire display surface of the liquid crystal panel 200A. As shown by the two-dot chain lines in FIGS. 3A to 3C, one of the adjacent liquid crystal panels 200A and 200B is provided. It may be provided only in the part. Similarly, the light guide element 300B may be provided on the entire display surface of the liquid crystal panel 200B, and as shown by two-dot chain lines in FIGS. 3A to 3C, adjacent liquid crystal panels 200A. It may be provided only in a part of 200B.

The liquid crystal panels 200A and 200B may be provided so that the ends thereof are close to each other, or may be provided in contact with each other. The liquid crystal display devices 100A and 100B are rotatably connected by a movable mechanism such as a hinge 2, for example. Thereby, in the electronic device 1, it can fold in the boundary part 3 of each liquid crystal display device 100A * 100B, and can change the relative angle of the display surface of these liquid crystal display devices 100A * 100B. . Such a movable mechanism is an example, and may be omitted, and the angle formed by the two display surfaces may be fixed. The configurations of the liquid crystal panels 200A and 200B and the light guide elements 300A and 300B will be described later.

(Configuration of liquid crystal display device)
Next, the configuration of the liquid crystal display devices 100A and 100B will be described with reference to FIG. (A) in FIG. 4 is a plan view showing a schematic configuration of a main part of the liquid crystal display device 100A according to the present embodiment, and (b) in FIG. 4 is shown in (a) in FIG. FIG. 6 is a cross-sectional view taken along line AA of the liquid crystal display device 100A. In the following description, the configuration of the liquid crystal display devices 100A and 100B will be described using the liquid crystal display device 100A as an example.

The liquid crystal display device 100A is a direct-view type display device, and includes a liquid crystal panel 200A and a light guide element 300A stacked on the liquid crystal panel 200A, as shown in FIG. The liquid crystal display device 100A is a transmissive liquid crystal display device, and a backlight 400A is provided on the back side of the liquid crystal display device 100A. The liquid crystal display device 100A performs display by modulating light emitted from the backlight 400A in the liquid crystal panel 200A.

First, the configuration of the liquid crystal panel 200A will be described. Various known liquid crystal panels can be used as the liquid crystal panel 200A. An example of the liquid crystal panel 200A is, for example, a TFT type VA mode liquid crystal panel, but is not limited thereto.

As shown in FIG. 4B, the liquid crystal panel 200A has a configuration in which a liquid crystal layer 230 is provided as an electro-optical element between the array substrate 210 and the counter substrate 220. The array substrate 210 has a configuration in which a switching element such as a thin film transistor (TFT) and a pixel electrode 212 are formed on an insulating substrate 211 such as glass. Further, optical film portions 240 and 250 including a polarizing plate and a retardation plate are respectively provided on the surfaces of the array substrate 210 and the counter substrate 220 opposite to the liquid crystal layer 230 as necessary.

As shown in FIGS. 4A and 4B, the liquid crystal panel 200A includes a display area 202 and a frame area 203 (non-display area) formed on the periphery of the liquid crystal panel that is outside the display area 202. ). In the display area 202 of the liquid crystal panel 200A, a plurality of pixels 201 are arranged in a matrix along the x-axis direction and the y-axis direction that are parallel to the display surface and orthogonal to each other. The pixels 201 are arranged at an equal pitch in each of the x-axis direction and the y-axis direction. In the present embodiment, the horizontal direction of the display surface of liquid crystal panel 200A is the x-axis direction, and the vertical direction of the display surface of liquid crystal panel 200A is the y-axis direction.

The color filter layer 222 is formed corresponding to each pixel 201. In this embodiment, the color filter layer 222 of each color of RGB (R: red, G: green, B: blue) is used as the color filter layer 222 as shown in FIG. The case where it is provided along the y-axis direction of the panel 200A will be described as an example. However, the present embodiment is not limited to this. The type of the color filter layer 222 is not limited to three types of RGB, and a plurality of types are arbitrarily selected from RGBYCM (R: red, G: green, B: blue, Y: yellow, C: cyan, M: magenta). It may be a thing.

(Configuration of light guide element)
Next, the configuration of the light guide element 300A will be described. The light guide element 300 </ b> A has a plurality of light guide portions 310. Each light guide unit 310 includes a light transmitting layer as a light transmitting unit, and includes a metal layer (reflection layer) as a reflecting unit. The light transmitting part and the reflecting part are stacked in parallel with each other. Therefore, in other words, the light guide unit 310A is configured by repeatedly stacking the light transmitting unit and the reflecting unit in parallel with each other.

The light incident from the incident surface 301 of the light guide element 300 </ b> A propagates through the light transmitting portion and is emitted from the emission surface 302. At this time, the light incident on the light transmitting part propagates in the light transmitting part while being reflected by the reflecting part provided between the light transmitting parts. For this reason, a translucent layer functions as a light guide path (light guide layer). Note that the reflection part of the light guide element 300A does not need to be provided on the entire boundary surface of the light transmission part, and is provided so that light incident on the light transmission part can be reflected and propagated by the reflection part. It only has to be.

The light guide unit 310 includes a light-transmitting layer as described above, and is provided in parallel to each other in the thickness direction. Therefore, the boundary surface 303 (layer surface, contact surface) of each light guide unit 310 with another light guide unit 310 is provided in parallel with each other. Further, the boundary surfaces (layer surfaces, contact surfaces) of the layers constituting each light guide unit 310 are also provided in parallel to each other.

The light guide element 300A has a structure in which a boundary surface 303 is inclined with respect to an incident surface 301 on which light emitted from the liquid crystal panel 200A is incident and an output surface 302 that emits the light. . In the light guide element 300A, the incident surface 311 of at least a part of the light guide unit 310 among the plurality of light guide units 310 overlaps a part of the display area 202 of the liquid crystal panel 200A, and the emission surface 312 of the light guide unit 310 is formed. The liquid crystal panel 200 </ b> A is disposed so as to overlap at least a part of the frame region 203. The inclination angle of the boundary surface 303, in other words, the inclination angle of the boundary surface (layer surface) of each layer constituting the light guide unit 310 is set to an angle that results in the above arrangement.

The light guide element 300A is stacked on the liquid crystal panel 200A so that the incident surface 301 and the display surface of the liquid crystal panel 200A are in close contact with each other. The light guide element 300A and the liquid crystal panel 200A may be bonded together via a light-transmitting adhesive (not shown). By doing so, there is an effect that the light guide element 300A can be prevented from being displaced and the light reflection at the interface between the light guide element 300A is reduced and light can be efficiently incident on the light guide element.

The light guide element 300A used in the present embodiment has a flat plate shape as shown in FIG. The incident surface 301 and the emission surface 302 of the light guide element 300A are provided in parallel to the display surface of the liquid crystal panel 200A. Therefore, the light guide part 310 of the light guide element 300A is formed so as to extend obliquely from the normal line direction rather than the normal line direction with respect to the display surface of the liquid crystal panel 200A.

The light that has entered the light guide element 300A from one end face of each light-transmitting part is reflected by the reflecting part, propagates through the light-transmitting part, and is emitted from the other end face of the light-transmitting part. In the light guide element 300A, a part of the light emitted from the display area 202 of the liquid crystal panel 200A by the light guide part 310 provided so as to be inclined with respect to the display surface of the liquid crystal panel 200A in this way is placed on the frame area 203. Lead. Accordingly, when the liquid crystal display device 100A is viewed from above the light guide element 300A, an image can be visually recognized in the areas on the display area 202 and the frame area 203 of the liquid crystal panel 200A.

(Arrangement of light guide element)
Next, the arrangement of the light guide elements 300A and 300B in the liquid crystal display devices 100A and 100B will be described with reference to FIG. (A) and (b) in FIG. 5 are the boundaries between the light guide portions 310 adjacent to each other on the emission surface 302 of each light guide element 300A / 300B when the liquid crystal display devices 100A / 100B are arranged adjacent to each other in the horizontal direction. In the example, the line tilt direction (in other words, the line tilt direction formed by the boundary surface 303 in plan view) is symmetrical with respect to the light guide element 300A and the light guide element 300B. FIG. 5A is a plan view showing the relationship between the images displayed on the liquid crystal panels 200A and 200B at this time and the images actually visible through the light guide elements 300A and 300B. (B) in FIG. 5 is a cross-sectional view showing the inclination direction of the boundary surface 303 in the liquid crystal display device 100A shown in (a) in FIG.

In the present embodiment, as shown in FIG. 5A, the inclination direction of the boundary surface 303 of each of the light guide elements 300A and 300B in the plan view is the boundary portion 3 of the liquid crystal display devices 100A and 100B (that is, The light guide elements 300A and 300B are arranged so as to be line-symmetric with respect to the boundary 3) of the two screens. In addition, as shown in FIG. 5B, in order to display an image in the frame region 203 adjacent to the liquid crystal display device 100A / 100B with the boundary portion 3 therebetween, in the cross section of each light guide element 300A / 300B. The boundary surface 303 is provided to be inclined toward the boundary portion 3 so as to be line symmetric at the boundary portion 3.

As a result, in any of the liquid crystal display devices 100A and 100B, images that are actually visible with respect to the images displayed on the liquid crystal panels 200A and 200B are Δx in the same direction (upward) in the vertical direction. Shift uniformly. Accordingly, the vertical shift amounts of the liquid crystal display devices 100A and 100B coincide with each other, and when the display image is viewed through the light guide elements 300A and 300B, the display image shift (display shift, image shift) that occurs between the liquid crystal display devices 100A and 100B. Offset) is offset. Therefore, since it is possible to display between the liquid crystal display devices 100A and 100B without image displacement, it is difficult to see the frame at the boundary 3. Here, in the present embodiment, in a plan view (that is, when the liquid crystal display device 100A is viewed from above), the direction of the boundary line between the adjacent light guide units 310 and the length of the frame region 203 for displaying an image are displayed. The angle θ formed by the pixel rows parallel to the direction is preferably 5 ° <θ <85 °.

In the present embodiment, the case where the liquid crystal display devices 100A and 100B are arranged adjacent to each other in the horizontal direction has been described as an example, and thus the shift direction of the display image is set to the vertical direction. Is not limited to this. The shift of the display image is adjacent to the frame region 203 for displaying the image (that is, the frame region 203 at the boundary portion 3 between the liquid crystal display devices 100A and 100B adjacent to each other when tiling is performed as described above). It occurs along the arrangement pattern of the pixels 201. For this reason, when the liquid crystal display devices 100A and 100B are arranged in the vertical direction (vertical direction) when the liquid crystal display devices 100A and 100B are adjacent in the horizontal direction (that is, arranged side by side on the same plane), The direction of shift along the direction is the horizontal direction. This is because the arrangement direction of the pixels 201 adjacent to the frame region 203 is the horizontal direction. Therefore, when the liquid crystal display devices 100A and 100B are arranged in the vertical direction, the shift direction only changes from the horizontal direction to the vertical direction, and the same can be said as in the case where the liquid crystal display devices 100A and 100B are arranged in the horizontal direction. Therefore, in this case, “vertical direction” and “vertical direction” may be read as “lateral direction” and “horizontal direction”, respectively.

(Structure of light guide element)
Below, the detailed structure of light guide element 300A * 300B which concerns on this Embodiment is demonstrated with reference to FIG. FIG. 6 is a cross-sectional view showing a light guide element 300A according to the present embodiment. In the following description, the structure of the light guide elements 300A and 300B will be described using the light guide element 300A as an example.

As shown in FIG. 6, the light guide part 310 of the light guide element 300 </ b> A has a multilayer structure, and includes a light transmissive part made of a light transmissive layer 324 such as a polymer film and a reflective part made of a metal layer 321. ing. Adjacent light guides 310 are bonded to each other by an adhesive layer 323.

As the light guide element 300A, for example, a light guide element made of an optical fiber face plate as used in Patent Documents 1 and 2 can be used, but from the sheet laminate 320 having the laminated structure shown in FIG. It is preferable to use a light guide element. FIG. 7 is a cross-sectional view showing an example of the structure of the sheet laminate 320 used in the light guide element 300A.

7 is a laminated body in which a metal layer 321 and a light transmitting layer 324 are repeatedly laminated in this order in parallel. When the light guide element 300 </ b> A includes the sheet laminate 320, each light guide unit 310 of the light guide element 300 </ b> A includes a metal layer 321, a light transmissive layer 324, and an adhesive layer 323 as illustrated in FIG. 7. . The sheet laminate 320 includes the metal layer 321, the translucent layer 324, and the adhesive layer 323 in the thickness direction (that is, the thickness of the light guides 310 (thickness in the stacking direction) becomes a desired pitch (that is, The layers are stacked repeatedly in this order in parallel with each other in a direction perpendicular to the light propagation direction.

When the sheet laminate 320 is used as the light guide element 300A, the light that has entered the light guide element 300A from the incident surface 301 propagates through the light-transmitting layer 324 and is emitted from the emission surface 302 toward the viewer. At this time, the light incident on the light transmitting layer 324 propagates in the light transmitting layer 324 while being reflected by the adjacent metal layer 321. That is, in the sheet laminate 320, the light-transmitting layer 324 functions as a light guide path (light-transmitting portion), while the boundary surface (layer surface) between the light-transmitting layer 324 and the metal layer 321 functions as a reflecting surface (reflecting portion). To do. Although light is incident on the incident surface 311 from various angles, all light can be guided regardless of the incident angle because the sheet laminate 320 uses metal reflection in the metal layer 321.

(Production method of light guide element using sheet laminate)
Next, a method of manufacturing the light guide element 300A using the sheet laminate 320 will be described with reference to (a) to (c) in FIG. (A) to (c) in FIG. 8 are diagrams showing a method of manufacturing the light guide element 300A using the sheet laminate in the order of steps. In the following description, the manufacturing method of the light guide element 300A will be described using specific numerical values and materials, but these numerical values and materials are examples. Therefore, the present embodiment is not limited to the following specific examples.

First, as shown in FIG. 8A, a sheet laminate 320 in which a plurality of sheets are laminated is prepared. First, as a transparent polymer film (transparent film) to be the light-transmitting layer 324, for example, an acrylic film having a thickness of 75 μm, a TAC (triacetylcellulose) film, or a COP (cyclo-olefin polymer) is used. Resin) film etc. are prepared. In addition, it is preferable that these films are not extended | stretched for the reason mentioned later.

Next, for example, a silver layer having a thickness of 100 nm is formed on the polymer film as the metal layer 321. The metal layer 321 can be formed by, for example, a vacuum deposition method or the like.

Subsequently, an adhesive layer 323 having a thickness of 3 μm is formed on the silver layer using, for example, a hot-melt adhesive (thermoplastic resin). A plurality of sheets (polymer film, metal layer, and hot melt adhesive) obtained in this manner are stacked and pressure bonded. Thereafter, the plurality of sheets are bonded to each other, for example, by melting the hot melt adhesive in an oven at 140 ° C. Note that the adhesive layer 323 is only required to be a material that is at least light transmissive and that allows films to adhere to each other. In addition to a hot melt adhesive, a thermosetting adhesive, a photocurable adhesive, or an adhesive. A sheet or the like can be substituted.

Next, as shown in (b) of FIG. 8, the sheet laminate 320 shown in (a) of FIG. 8 is cut along a cutting line (cut plane) that forms a predetermined angle with respect to the boundary surface of the sheet laminate 320. ) Cut along CL1 and CL2 to cut out a flat sheet laminate 320 having a predetermined thickness from the sheet laminate 320. The sheet laminate 320 can be cut using various known cutting methods. For example, a laser cutting method or the like can be used, but it is particularly preferable to use a multi-wire saw. Since the multi-wire saw is cut using a plurality of wires arranged in parallel to each other, a plurality of flat sheet laminates 320 can be cut out simultaneously. In addition, when a wire saw is used, there is an advantage that costs associated with cutting can be reduced as compared with the case of using a rotary blade or a belt-like blade. In addition, as a multi-wire saw, a loose abrasive grain type may be used and a fixed abrasive grain type may be used.

Subsequently, the cut surface of the sheet laminate 320 is subjected to processing such as polishing as necessary, and the surface of the cut sheet laminate 320 is washed and dried as necessary. Thereby, as shown to (c) in FIG. 8, 300 A of light guide elements which consist of the sheet | seat laminated body 320 can be obtained. The surface on which processing such as polishing is performed is appropriately selected as necessary.

(Reduction in reduction of transmittance in light guide element)
As described above, conventionally, there has been a problem that loss of light amount due to light reflection in the metal layer of the light guide portion of the light guide element leads to a decrease in transmittance of the light guide element. As a cause of lowering the reflectance in the metal layer, there is a polarization characteristic of reflectance. Therefore, in the light guide elements 300A and 300B according to the present embodiment, a contrivance is made with respect to the polarization characteristics of the reflectance in order to reduce the decrease in the reflectance of the metal layer 321. The device will be described below.

It is generally known that metal reflection has polarization dependency. This polarization dependency will be described with reference to FIG. 9 and FIG. FIG. 9 is a diagram schematically showing incident light on the metal layer. FIG. 10 is a diagram showing the angle characteristics of the polarization reflectance of the metal layer. In addition, angle (phi) shown in FIG. 9 is an incident angle of the incident light to a metal layer.

As shown in FIG. 9, S-polarized light is light polarized parallel to the reflecting surface (metal layer), and P-polarized light is light polarized perpendicular to the reflecting surface (metal layer). It is. As shown in FIG. 10, at the normal incidence (φ = 0 °), the reflectance of both S-polarized light and P-polarized light is approximately 98%, but as φ increases, the reflectance of S-polarized light increases. On the other hand, the reflectance of P-polarized light decreases as φ increases, becomes minimum near φ = 70 °, and increases again after φ = 70 °.

For example, when the inclination angle θ of the light guide element is 45 °, the light emitted in the normal direction from the display surface of the liquid crystal display device enters the metal layer at an angle of 45 °. Therefore, φ = 45 °. According to the graph shown in FIG. 10, there is a difference of 1% or more in the reflectance between the S-polarized light and the P-polarized light when φ = 45 °. This corresponds to a difference of about 15% or more when converted to the transmittance of the light guide element. In the range of φ = 50 ° to 80 ° where the difference in reflectance between S-polarized light and P-polarized light is particularly large, the difference in transmittance is further increased.

Since the liquid crystal display device emits light in various directions, there is much light incident on the metal layer at an incident angle of 50 ° to 80 °. Therefore, it can be seen that the polarization state of the light incident on the metal layer has a great influence on the transmittance of the light guide element. Here, in the liquid crystal display device, since the polarizing plate is disposed on the outermost surface, the emitted light is basically polarized light. Therefore, it is considered that the transmittance of the light guide element can be improved by adjusting the direction of the polarizing plate so that the polarized light incident on the reflection surface of the light guide element becomes S-polarized light. There is no literature that clearly defines the proper arrangement method.

Therefore, in the present embodiment, the arrangement of the polarizing plates of the liquid crystal panels 200A and 200B is adjusted so that the highly polarized S-polarized light is incident on the light guide elements 300A and 300B. The arrangement adjustment of the polarizing plate will be described with reference to FIG. 1 and FIG. 1A is a plan view showing the liquid crystal display device 100A, and FIG. 1B shows the inclination direction of the boundary surface 303 in the liquid crystal display device 100A shown in FIG. It is sectional drawing shown. 2A is a plan view showing the liquid crystal display device 100A, and FIG. 2B is an inclination of the boundary surface 303 in the liquid crystal display device 100A shown in FIG. It is sectional drawing which shows a direction. Below, taking the liquid crystal display device 100A as an example, the arrangement of the polarizing plates of the liquid crystal display devices 100A and 100B will be described.

As shown in FIG. 1A, in the liquid crystal display device 100A, in the plan view (that is, when the liquid crystal display device 100A is viewed from above), the direction of the boundary surface 303 of the light guide element 300A and the polarizing plate The polarizing plates are arranged so that the directions of the light transmission axis (arrow α in the figure) are parallel to each other. Therefore, the direction in which the boundary surface 303 extends in the plane direction coincides with the direction of the light transmission axis of the polarizing plate. Accordingly, since S-polarized light is incident on the light guide element 300A, it is possible to suppress a decrease in reflectance in the metal layer 321. That is, a decrease in reflectance in the metal layer 321 can be suppressed and the light utilization efficiency can be increased. As a result, the transmittance of the light guide elements 300A and 300B is improved. Therefore, since the transmittance of the light guide elements 300A and 300B is low, it is not necessary to compensate for the decrease in the luminance of the liquid crystal display devices 100A and 100B by increasing the luminance of the backlight device 400, and thus the liquid crystal display devices 100A and 100B. It is possible to solve the problem that the power consumption increases.

In addition, like the liquid crystal display device 100A shown in FIG. 2A, the direction of the boundary surface 303 between the light guide portions 310 adjacent to each other in plan view (that is, when the liquid crystal display device 100A is viewed from above). And a pixel row parallel to the longitudinal direction of the frame region 203 for displaying an image is inclined at an angle θ with respect to the longitudinal direction of the frame region 203, It is preferable to set the direction of the light transmission axis. That is, also in this case, the direction in which the boundary surface 303 extends in the surface direction coincides with the direction of the light transmission axis of the polarizing plate. Accordingly, since S-polarized light is incident on the light guide element 300A, it is possible to suppress a decrease in reflectance in the metal layer 321.

By the way, if the material used for the translucent layer 324 has a characteristic (birefringence) that changes the polarization state of light, the polarization state of the light changes as light is guided through the translucent layer 324 (that is, However, the reflectivity of the metal layer also decreases. Therefore, it is preferable to use a material with little birefringence for the light-transmitting layer 324, and it is more preferable to use a material with little birefringence (non-birefringent material). A PET film generally used industrially has a relatively large birefringence, and therefore has a great influence on the reflectance. On the other hand, an acrylic film, a TAC film, a COP film, or the like is preferably used as the light-transmitting layer 324 because of low birefringence and high transmittance. Alternatively, a glass substrate may be used for the light-transmitting layer 324 as a non-birefringent material. In addition, when extending | stretching with respect to said film, since there exists a possibility that birefringence may arise in an extending | stretching direction, it is more preferable not to perform an extending | stretching process.

Here, birefringence is often discussed using retardation (= birefringence × thickness) in general. A PET film and a PC (polycarbonate) film having a relatively large birefringence have a retardation of about 20 nm or more in a general thickness (for example, 100 μm). On the other hand, an acrylic film, a TAC film, and a COP film having relatively small birefringence have a retardation of about 10 nm or less at a general thickness (for example, 80 to 100 μm). In particular, the retardation of the TAC film and the COP film is 5 nm or less. Since the glass substrate is basically isotropic, birefringence is zero. From the above, it can be said that the preferable condition for the material used for the light-transmitting layer 324 is a retardation of 10 nm or less, more preferably 5 nm or less.

(Example 1 and Comparative Example 1)
The liquid crystal display device 100A including the light guide element 300A manufactured based on the first embodiment described above is referred to as Example 1, and a liquid crystal display device including the following light guide element is manufactured as Comparative Example 1, and Example 1 is performed. And Comparative Example 1 was examined. FIG. 11 is a cross-sectional view showing a light guide element manufactured as Comparative Example 1.

First, as Example 1, a liquid crystal display device 100A including a light guide element 300A as shown in FIG. A light guide element 300A using a silver layer as the metal layer 321 and an acrylic film as the light-transmitting layer 324 was manufactured.

On the other hand, as Comparative Example 1, as shown in FIG. 11, a liquid crystal display device including a light guide element 300E using a PET film as the light-transmitting layer 324 was produced. A light guide element 300E using a silver layer as the metal layer 321 was manufactured in the same manner as in Example 1 except that a PET film was used as the light transmissive layer 324.

The luminance of each liquid crystal display device of Example 1 and Comparative Example 1 was measured using a luminance meter (MB-5A manufactured by Topcon Corporation). When the luminance before and after the light guide element was measured and the ratio was determined as the transmittance, it was as shown in Table 1.

As shown in Table 1, in Example 1, a very high transmittance was obtained. On the other hand, in Comparative Example 1, the decrease in luminance was remarkably large. Hereinafter, each Example 1 and Comparative Example 1 will be described in detail.

First, from the results of Example 1 and Comparative Example 1, it was found that the transmittance was lowered by using a PET film as the light-transmitting layer. As described above, this is because the PET film has a relatively large birefringence and changes the polarization state of light. If the polarization state of the light changes, the light incident on the light guide element is not S-polarized light, which greatly affects the reflectance. Therefore, it was found that the transmittance can be improved by using an acrylic film, a TAC film, a COP film or the like having a small birefringence as the light transmitting layer.

(Comparative Example 2)
Then, the liquid crystal display device provided with the following structures as another comparative example 2 was examined. (A) in FIG. 12 is a plan view showing liquid crystal display devices 100C and 100D manufactured as Comparative Example 2, and (b) in FIG. 12 is a liquid crystal display device 100C shown in (a) in FIG. -It is sectional drawing which shows the inclination direction of the boundary surface 303 in 100D.

In Comparative Example 2, the direction of the boundary surface 303 of the light guide elements 300C and 300D and the direction of the light transmission axis of the polarizing plate are parallel to each other in plan view (that is, when the liquid crystal display devices 100C and 100D are viewed from above). The polarizing plate is arranged so as not to become. Therefore, the direction in which the boundary surface 303 extends in the surface direction does not match the direction of the light transmission axis of the polarizing plate.

As shown in FIG. 12A, when the angle between the direction of the boundary surface 303 of the light guide element 300D and the direction of the light transmission axis of the polarizing plate (arrow γ in the figure) is θ ′, the comparison is made. In Example 2, θ ′ ≠ 0 ° (θ ′ = 0 ° in Example 1). The same applies to the light guide element 300C. In addition, it was set as the structure similar to Example 1 except the point which has different arrangement | positioning of a polarizing plate.

FIG. 13 shows data of transmittance corresponding to the angle θ ′ in the configuration of Comparative Example 2. FIG. 13 is a diagram showing the results of luminance measurement using a luminance meter (MB-5A manufactured by Topcon) from the normal direction of the liquid crystal display devices 100C and 100D.

As shown in FIG. 13, it was found that the transmittance was highest in the case of Example 1 (that is, when θ ′ = 0 ° (θ ′ = 180 °)). On the other hand, in the case of Comparative Example 2 (that is, in the case of θ ′ ≠ 0 ° (θ ′ ≠ 180 °)), the transmittance is low, and in particular, the transmittance is the lowest near θ ′ = 90 °. I understand. That is, it can be said that the transmittance decreases as the direction of the boundary surface 303 of the light guide elements 300C and 300D and the direction of the light transmission axis of the polarizing plate approach an orthogonal state. Therefore, it is most preferable to dispose the polarizing plate so that the direction of the boundary surface 303 of the light guide elements 300C and 300D is parallel to the direction of the light transmission axis of the polarizing plate. However, in the range of θ ′ = 0 ± 30 °, the amount of decrease in transmittance is in the range of about 10%.

[Embodiment 2]
This embodiment will be described as follows based on (a) and (b) in FIG. Note that in this embodiment, differences from Embodiment 1 are described, and description of the same configuration is omitted. Moreover, the same number is attached | subjected to the component which has a function similar to Embodiment 1, and the description is abbreviate | omitted. (A) in FIG. 14 is a plan view showing liquid crystal display devices 100A and 100B according to the present embodiment, and (b) in FIG. 14 is liquid crystal display device 100A shown in (a) in FIG. It is sectional drawing which shows the inclination direction of the boundary surface 303 in FIG.

In the first embodiment, the case where the flat light guide elements 300A and 300B are provided on the entire display surface of the liquid crystal panels 200A and 200B has been described as an example. The case where the light guide elements 300 </ b> A and 300 </ b> B are provided only in the part area will be described as an example. In the present embodiment, as in the first embodiment, an image is displayed on the frame region 203 adjacent to each other with the boundary 3 between the liquid crystal display devices 100A and 100B. In the present embodiment, as shown in FIG. 14A, the light guide elements 300A and 300B are provided only in the frame regions 203 at the ends adjacent to each other in the liquid crystal display devices 100A and 100B and in the vicinity thereof. Is provided. Accordingly, the area where the light guide elements 300A and 300B are provided can be reduced, and the manufacturing cost of the liquid crystal display devices 100A and 100B can be reduced.

In the present embodiment, light guide elements 300A and 300B can be provided as in the liquid crystal display devices 100A and 100B shown in FIG. (A) in FIG. 15 is a plan view showing the liquid crystal display devices 100A and 100B according to the present embodiment, and (b) in FIG. 15 is a liquid crystal display device 100A shown in (a) in FIG. It is sectional drawing which shows the inclination direction of the boundary surface 303 in FIG.

As shown to (a) in FIG. 15, you may provide a light guide element also in the frame region 203 of the edge part which opposes the edge part mutually adjacent in liquid crystal display device 100A * 100B, and its vicinity. . By arranging in this manner, a tile display in which liquid crystal display devices having three or more screens are arranged can be configured.

(Configuration of light guide element)
In the light guide elements 300 </ b> A and 300 </ b> B, a cross section perpendicular to the longitudinal direction of the frame region 203 is a triangular prism having a right triangle shape. Therefore, the light guide elements 300A and 300B used in the present embodiment have the incident surfaces 301 parallel to the display surfaces of the liquid crystal panels 200A and 200B, but the exit surfaces 302 are in relation to the display surfaces of the liquid crystal panels 200A and 200B. Is inclined. More specifically, the exit surfaces of the light guide elements 300A and 300B have a thickness that increases toward the end facing the adjacent ends of the liquid crystal panels 200A and 200B. It is inclined with respect to the display surface of 200B. However, the light guide elements 300A and 300B have a rectangular shape (square shape or rectangular shape) in plan view. In addition, the incident surfaces 301 of the light guide elements 300A and 300B are formed flat (that is, flat).

Note that the liquid crystal display devices 100A and 100B emit light from the display regions 202 of the liquid crystal panels 200A and 200B and the light guide elements 300A and 300B, as indicated by dotted lines in FIG. 14B and FIG. 15B. You may have the translucent cover sheet 350A * 350B which covers the surface 302. FIG. The translucent cover sheets 350A and 350B are formed, for example, along the shapes of the emission surfaces 302 of the light guide elements 300A and 300B and the display surfaces of the liquid crystal panels 200A and 200B. The light guide elements 300A and 300B and the translucent cover sheets 350A and 350B are bonded to each other through, for example, an adhesive layer. However, the adhesive layer is not necessarily required, and the light guide elements 300A and 300B and the translucent cover sheets 350A and 350B may be fixed via an air layer. The display surfaces of the light guide elements 300A and 300B and the liquid crystal panels 200A and 200B are protected by bonding the light-transmitting cover sheets 350A and 350B to the light guide elements 300A and 300B to form a flat sheet. can do. In addition, since the surfaces of the liquid crystal display devices 100A and 100B are flattened, the uncomfortable appearance is reduced. Furthermore, there is an advantage that the dirt on the surface can be easily wiped off. The translucent cover sheets 350A and 350B are formed of a transparent resin such as an acrylic resin, for example. By providing the translucent cover sheets 350A and 350B, the display quality of the liquid crystal display devices 100A and 100B can be improved.

(Advantages of using a triangular light guide element)
The translucent cover sheets 350A and 350B are not always necessary. That is, according to the present embodiment, it is not necessary to use a light guide element having the same size as the liquid crystal panels 200A and 200B. Therefore, it is possible to reduce the weight of the liquid crystal display devices 100A and 100B and the electronic devices using the liquid crystal display devices 100A and 100B, and to manufacture these devices or devices at low cost.

In addition, the light guide element 300A as described above can be provided, for example, in two opposing frame regions 203 in one liquid crystal panel, and the inclination angle and the inclination direction of the boundary surface 303 of the light guide unit 310. Can be set for each light guide element 300A. Therefore, for example, by providing a light guide element in each of two opposing frame regions 203 in one liquid crystal panel, whether or not a plurality of liquid crystal display devices are used, or a boundary portion between the liquid crystal display devices An image can be displayed in each frame area 203 regardless of whether or not. For this reason, a much larger display screen can be realized.

(Improvement of light guide element transmittance)
Also in the present embodiment, in the liquid crystal display device 100A, in plan view (that is, when the liquid crystal display device 100A is viewed from above), the direction of the boundary surface 303 of the light guide element 300A and the direction of the light transmission axis of the polarizing plate The polarizing plates are arranged so that are parallel to each other. Therefore, the direction in which the boundary surface 303 extends in the plane direction coincides with the direction of the light transmission axis of the polarizing plate. Accordingly, since S-polarized light is incident on the light guide element 300A, it is possible to suppress a decrease in reflectance in the metal layer 321. That is, a decrease in reflectance in the metal layer 321 can be suppressed and the light utilization efficiency can be increased. As a result, the transmittance of the light guide elements 300A and 300B is improved. Therefore, since the transmittance of the light guide elements 300A and 300B is low, it is not necessary to compensate for the decrease in the luminance of the liquid crystal display devices 100A and 100B by increasing the luminance of the backlight device 400, and thus the liquid crystal display devices 100A and 100B. It is possible to solve the problem that the power consumption increases.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and can be obtained by appropriately combining technical means disclosed in different embodiments. Embodiments are also included in the technical scope of the present invention.

[Summary of Embodiment]
As described above, the display device according to one embodiment of the present invention is characterized in that the retardation of the light-transmitting layer is 10 nm or less.

The display device according to one embodiment of the present invention is characterized in that the retardation of the light transmitting layer is 5 nm or less.

According to the above configuration, the polarization state of incident light can be prevented from changing due to the characteristics (birefringence) of the light transmitting layer. Therefore, by using a material with low birefringence for the light-transmitting layer, the polarization state of the light incident on the light guide element does not change, and S-polarized light is incident. Therefore, it is possible to suppress a decrease in reflectance in the reflective layer. .

The display device according to one embodiment of the present invention is characterized in that the light-transmitting layer is any one of an acrylic film, a triacetyl cellulose film, a cycloolefin resin film, and a glass substrate.

Since acrylic film, triacetyl cellulose film, cycloolefin resin film, and glass substrate are materials with relatively little birefringence, according to the above configuration, the change in the polarization state of light incident on the light guide element can be suppressed. Can do.

In the display device according to one embodiment of the present invention, an incident surface of the light guide element is parallel to the display surface of the display panel, and an output surface of the light guide element is at an end of the display panel. The display panel is inclined with respect to the display surface so as to increase in thickness, and the light guide element has a triangular triangular cross section in a direction perpendicular to the end of the display panel. It is characterized by.

According to the above configuration, the light guide element is provided only in the display area and the vicinity thereof. Accordingly, the area where the light guide element is provided can be reduced, so that the manufacturing cost of the display device can be reduced. Moreover, since it is possible to make it difficult to see the regions on the left and right sides of the display device, a tile display in which display devices having three or more screens are arranged can be configured.

Further, the electronic device according to one embodiment of the present invention is characterized in that it can be folded at a boundary portion between the adjacent display devices.

According to the above configuration, the display device can be folded at the boundary between the display devices, and the relative angle of the display surfaces of these display devices can be changed.

The specific embodiments or examples made in the detailed description section of the invention are merely to clarify the technical contents of the present invention, and are limited to such specific examples and are interpreted in a narrow sense. It should be understood that various modifications may be made within the spirit of the invention and the scope of the following claims.

The present invention can be used for various electronic devices having a display unit such as a mobile phone, an electronic book, a game machine, a TV (television), or a public bulletin board for outdoor use.

DESCRIPTION OF SYMBOLS 1 Electronic device 2 Hinge 3 Boundary part 100A-100D, 100 'Liquid crystal display device (display device)
200A to 200D, 200 'liquid crystal panel (display panel)
201 Pixel 202 Display area 203 Frame area 210 Array substrate 211 Insulating substrate 212 Pixel electrode 220 Counter substrate 222 Color filter layer 230 Liquid crystal layer 240, 250 Optical film portions 300A to 300E, 300 ′ Light guide elements 301, 311 Incident surfaces 302, 312 Outgoing surface 303 Boundary surfaces 310, 310A, 310B Light guide 320 Sheet laminate 321 Metal layer 323 Adhesive layer 324 Translucent layer 350 Translucent sheet 350A Translucent cover sheet 350B Translucent cover sheet 400 Backlight device 400A Back Light

Claims (7)

1. A display panel;
   A display device comprising a light guide element provided on the display surface side of the display panel,
   The light guide element is configured by repeatedly laminating a reflective layer made of metal and a light transmitting layer in parallel with each other,
   A polarizing plate is provided on the display surface side of the display panel,
   A display device characterized in that a direction in which a boundary surface between the reflective layer and the light transmitting layer extends in a plane direction of the display surface and a direction of a light transmission axis of the polarizing plate are parallel to each other.
2. The display device according to claim 1, wherein the retardation of the light transmitting layer is 10 nm or less.
3. The display device according to claim 2, wherein the retardation of the light transmitting layer is 5 nm or less.
4. The display device according to any one of claims 1 to 3, wherein the light transmitting layer is any one of an acrylic film, a triacetyl cellulose film, a cycloolefin resin film, and a glass substrate.
5. The incident surface of the light guide element is parallel to the display surface of the display panel,
   The exit surface of the light guide element is inclined with respect to the display surface of the display panel so that the thickness increases toward the end of the display panel,
   5. The display device according to claim 1, wherein in the light guide element, a cross section in a direction orthogonal to the end portion of the display panel is a triangular prism.
6. A plurality of display devices according to any one of claims 1 to 5,
   An electronic apparatus, wherein the plurality of display devices are arranged side by side on the same plane.
7. The electronic device according to claim 6, wherein the electronic device can be folded at a boundary portion between the adjacent display devices.

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