Light guide plate and display device

Abstract

To realize a light guide plate that can reduce distortion of an outline of a displayed image.SOLUTION: A light guide plate comprises: an incident surface on which light is incident; an emission surface from which light is emitted; and a light deflecting portion that reflects light and emits it from the emission surface. Cell regions (17A) provided with one or more light deflecting portions are provided in a matrix. Outlines of the cell regions have an inclined outline portion that is inclined with respect to a direction of an optical axis of the light incident from the incident surface and a direction perpendicular to the optical axis, as viewed from a direction perpendicular to the emission surface.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a light guide plate and a display device including the light guide plate.

Background Art

[0002] Patent Document 1 discloses a stereoscopic light device. The light device includes a light guide plate and a plurality of light deflecting portions that deflect light propagating in the light guide plate and emit light that forms an image in space from an emission surface.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a light device as disclosed in Patent Document 1, a region (pixel) of a certain size in the displayed image is displayed by a cell region in which one or more light deflecting portions are provided. Since the light deflecting portions included in this cell region need to reflect light over a wide range, it is necessary to provide a large number of light deflecting portions in the cell region or to provide light deflecting portions having surfaces with different reflection directions. Therefore, the cell region requires a certain amount of area.

[0005] However, depending on the area of the cell region, the size of the pixels in the displayed image also increases. Therefore, depending on the direction of the contour of the displayed image, there is a problem that distortion of the contour line due to the pixel size occurs.

[0006] One aspect of the present invention aims to realize a light guide plate capable of reducing distortion of the contour of a displayed image.

Means for Solving the Problems

[0007] To solve the above problems, a light guide plate according to one aspect of the present invention is a light guide plate that displays a display image which is a predetermined planar image or a three-dimensional image using a plurality of pixels, comprising: an incident surface into which light from a light source is incident; an exit surface from which the light is emitted; and a plurality of light deflection parts that reflect the light incident from the incident surface and guided, causing the light to be emitted from the exit surface, wherein a plurality of cell regions, each having one or more of the light deflection parts, are arranged in a matrix, and at least one of the following is true: (1) At least one of the row-direction arrangement direction and the column-direction arrangement direction of the cell regions has an inclined arrangement portion composed of a plurality of cell regions that, when viewed from a direction perpendicular to the exit surface, is inclined with respect to the direction of the optical axis of the light incident from the incident surface and a direction perpendicular to the optical axis; and (2) The contour of the cell region has an inclined contour portion that, when viewed from a direction perpendicular to the exit surface, is inclined with respect to the direction of the optical axis of the light incident from the incident surface and a direction perpendicular to the optical axis.

[0008] In conventional light guide plates, the cell regions are arranged in a matrix along the direction of the optical axis of the light incident from the incident surface and in a direction perpendicular to the optical axis. In this case, if an attempt is made to display a straight line or curve using cell regions arranged in a direction inclined with respect to the direction of the optical axis and the direction perpendicular to the optical axis, distortion of the contour line may occur due to the size of the pixels. In contrast, the above configuration makes it possible to provide inclined arrangement portions or inclined contour portions according to the direction of the contour of the image to be displayed. Therefore, distortion of the image contour can be reduced.

[0009] Furthermore, in a light guide plate according to one aspect of the present invention, the cell region is provided with a plurality of light deflection portions that reflect the light in different directions from each other.

[0010] In the above configuration, by providing multiple light deflection sections in the cell region, the direction of light reflected from the cell region can be broadened. Therefore, since each light deflection section can have a relatively simple shape, a light guide plate can be provided in which the light deflection sections are easy to form.

[0011] Furthermore, in a light guide plate according to one aspect of the present invention, at least a portion of the outline of the display image is displayed by the cell region constituting the inclined arrangement portion.

[0012] According to the above configuration, distortion of the contour displayed by the cell regions constituting the slanted arrangement portion can be reduced.

[0013] Furthermore, in a light guide plate according to one aspect of the present invention, at least a portion of the outline of the display image is displayed by the cell region having the inclined contour portion.

[0014] According to the above configuration, distortion of the contour displayed by the cell regions that constitute the sloping contour portion can be reduced.

[0015] Furthermore, in a light guide plate according to one aspect of the present invention, the relationship between the length of the sides of the contour parallel to the row direction of the cell region and the length of the sides of the contour parallel to the column direction is the same as the relationship between the size of the display image in the row direction and the size of the display image in the column direction.

[0016] According to the above configuration, the number of cell region boundaries is reduced in the direction of increasing display image size, thereby reducing distortion of the display image's contour.

[0017] Furthermore, in a light guide plate according to one aspect of the present invention, at least one of the arrangement of the plurality of cell regions constituting the inclined arrangement portion and the inclined contour portion is curved.

[0018] According to the above configuration, distortion of the contours of images with curved contours can be reduced.

[0019] Further, the light guide plate according to one aspect of the present invention has a first region including a plurality of the cell regions and a second region including a plurality of the cell regions, which is disposed at a position different from the first region, and at least one of the arrangement direction of the plurality of cell regions constituting the inclined arrangement portion and the direction of the inclined contour portion is different between the first region and the second region.

[0020] According to the above configuration, each of a plurality of display images having different contour directions can be displayed with reduced distortion.

[0021] Further, a display device according to one aspect of the present invention includes the light guide plate according to any of the above aspects and the light source.

Advantages of the Invention

[0022] According to one aspect of the present invention, a light guide plate capable of reducing the distortion of the contour of the displayed image can be realized.

Brief Description of the Drawings

[0023] [Figure 1] It is a perspective view of a display device according to an application example of the present invention. [Figure 2] It is a cross-sectional view of a display device according to an application example of the present invention. [Figure 3] It is a perspective view schematically showing a display device according to an application example of the present invention together with an image formed in space. [Figure 4] It is a diagram schematically showing a cell region that provides light toward a specific observation position. [Figure 5] It is a perspective view showing an example of the configuration of a light deflection unit. [Figure 6] It is a diagram schematically showing an example of the configuration of a cell region. [Figure 7] In the light guide plate according to the first configuration example, it is a plan view showing an example of a light guide plate region in which a plurality of cell regions are provided. [Figure 8] In the light guide plate according to the first configuration example, it is a plan view showing another example of a light guide plate region in which a plurality of cell regions are provided. [Figure 9]This is a plan view showing an example of a light guide plate region in the second configuration example, in which multiple cell regions are provided. [Figure 10] This is a plan view showing an example of a light guide plate region in the third configuration example, in which multiple cell regions are provided. [Figure 11] This is a plan view showing another example of a light guide plate region in the third configuration example, in which multiple cell regions are provided. [Figure 12] This is a plan view showing the configuration of the light guide plate region according to the first modified example. [Figure 13] This is a plan view showing the configuration of the light guide plate region according to the second modified example. [Figure 14] This is a plan view showing a specific example of the light guide plate region according to the second modified example. [Figure 15] This is a plan view of a light guide plate according to a third modified example. [Figure 16] This is a perspective view showing the arrangement of the light deflection elements according to the third modified example. [Figure 17] This is a perspective view showing a method for forming a three-dimensional image using a light guide plate according to a third modified example. [Modes for carrying out the invention]

[0024] Hereinafter, an embodiment relating to one aspect of the present invention (hereinafter also referred to as "this embodiment") will be described based on the drawings.

[0025] §1 Examples of Application Figure 1 is a perspective view of a display device 10 according to an application example of the present invention. Figure 2 is a cross-sectional view of the display device 10. As shown in Figures 1 and 2, the display device 10 comprises a light guide plate 11 and a light source 12.

[0026] The light guide plate 11 displays a display image, which is a predetermined planar or three-dimensional image, using multiple pixels. The light guide plate 11 has a rectangular parallelepiped shape and is molded from a resin material that is transparent and has a relatively high refractive index. For example, polycarbonate resin or polymethyl methacrylate resin can be used as the material for forming the light guide plate 11. In this application example, the light guide plate 11 is molded from polymethyl methacrylate resin. As shown in Figure 2, the light guide plate 11 has an exit surface 11a, a back surface 11b, and an incident surface 11c.

[0027] The emission surface 11a is the surface from which light guided through the interior of the light guide plate 11 is emitted, and whose optical path has been altered by the light deflection unit 13, which will be described later. The emission surface 11a constitutes the front surface of the light guide plate 11. The back surface 11b is a surface parallel to the emission surface 11a, and is the surface on which the light deflection unit 13, which will be described later, is located. The incidence surface 11c is the surface on which light emitted from the light source 12 is incident inside the light guide plate 11.

[0028] The light source 12 causes light to enter the interior of the light guide plate 11 from the incident surface 11c. The light emitted from the light source 12 and incident on the light guide plate 11 from the incident surface 11c is totally reflected at the exit surface 11a or the back surface 11b and guided through the light guide plate 11. The light source 12 is, for example, an LED (Light Emitting diode) light source.

[0029] Each drawing shows the XYZ coordinate axes. The exit surface 11a and the back surface 11b are planes parallel to the XY plane. In particular, the optical axis direction of the light incident on the light guide plate 11 from the light source 12 is the Y axis direction. The direction parallel to the exit surface 11a and the back surface 11b and perpendicular to the Y axis direction is the X axis direction. Furthermore, the direction perpendicular to both the X axis direction and the Y axis direction is the Z axis direction.

[0030] As shown in Figure 2, multiple light deflection sections 13 are formed on the back surface 11b of the light guide plate 11. The light deflection sections 13 change the optical path of the light guided through the light guide plate 11 and cause it to be emitted from the emission surface 11a.

[0031] Figure 3 is a schematic perspective view showing the display device 10 along with the image formed in space. In the example shown in Figure 3, the display device 10 displays an image I (display image) in space by light emitted from the emission surface 11a. Image I is an image of the letter "A" located on the positive Z-axis side of the emission surface 11a.

[0032] As shown in Figure 3, the light guide plate 11 of the display device 10 has multiple cell regions 15 arranged in a matrix. Each cell region 15 is a region where one or more light deflection units 13 are provided. Each cell region displays an image I by changing the light propagating within the light guide plate 11 and emitting it from the emission surface 11a.

[0033] Figure 3 shows cell regions 15a, 15b, and 15c as examples of cell regions 15. Figure 3 shows how light from cell region 15a spreads out toward several locations in image I. The same is true for cell regions 15b, 15c, and the other cell regions 15.

[0034] Each of the cell regions 15 occupies a small area within the back surface 11b. Each of the cell regions 15 is smaller than the area occupied when image I is projected onto the XY plane. Image I is formed by light from numerous cell regions 15, each spreading light toward various positions within the image. In other words, the light from numerous cell regions 15 forms light diverging from image I.

[0035] Figure 4 schematically shows a light deflection unit 13 that provides light directed towards a specific observation position. Figure 4 shows cell regions 15d, 15e, 15f, and 15g as examples of cell regions 15. For example, the light that forms the lower end of the left hypotenuse of the "A" shape in image I is provided by light from a specific reflective surface within cell region 15e and light from a specific reflective surface within cell region 15f, and not by light from cell regions 15d and 15g. Thus, when viewed from a specific observation position, a specific part of image I is formed by light from a specific cell region 15 among the multiple cell regions 15.

[0036] Figure 5 is a perspective view showing an example of the configuration of the light deflection section 13. In the example shown in Figure 5, the light deflection section 13 is triangular pyramidal in shape and has a single reflective surface 14 that reflects (total internal reflection) the incident light. The light deflection section 13 may be, for example, a recess formed on the back surface 11b of the light guide plate 11. Note that the light deflection section 13 is not limited to a triangular pyramidal shape.

[0037] Furthermore, the reflective surface 14 in the example shown in Figure 5 is a flat surface. However, the shape of the reflective surface 14 is not limited to a flat surface; it may also be a curved surface.

[0038] Figure 6 is a schematic diagram showing an example of the configuration of a cell region 15. In the example shown in Figure 6, the cell region 15 has a configuration in which multiple light deflection sections 13 are provided that reflect light in different directions from each other. By providing multiple light deflection sections 13 in each cell region 15, the direction of light reflected from the cell region 15 can be broadened. Therefore, each light deflection section 13 can have a relatively simple shape, making it possible to provide a light guide plate 11 in which the light deflection sections 13 are easy to form.

[0039] The light deflection sections 13 may all be provided separately, or some may be provided in contact with each other. Furthermore, the arrangement pattern of the light deflection sections 13 may differ depending on the position where the cell region 15 is provided. The shape of the light deflection sections 13 is not particularly limited as long as they have a reflective surface capable of changing the optical path of light.

[0040] Furthermore, one light deflection unit 13 may have multiple reflective surfaces. In that case, one cell region 15 may have only one light deflection unit 13.

[0041] The display device according to the present invention comprises a light guide plate 11 and a light source 12, according to the configuration examples and modifications described below. As described above, the light guide plate 11 may project an image into a space other than the emission surface 11a. Alternatively, the light guide plate 11 may be a light guide plate for displaying planar images, projecting an image onto the surface of the emission surface 11a. Furthermore, the light guide plate 11 may project an image onto both the surface of the emission surface 11a and a space other than the emission surface 11a. When the light guide plate 11 projects an image onto the emission surface 11a, each light deflection section 13 may have a concave reflective surface to widen the angle at which the image can be viewed. Such a display device 10 can be applied to various applications such as amusement equipment, in-vehicle devices, home appliances, or the operation section of other switches.

[0042] §2 Example Configuration (Configuration Example 1) Figure 7 is a plan view showing an example of a light guide plate region in the light guide plate 11 according to the first configuration example, in which multiple cell regions 17A are provided. As shown in Figure 7, the light guide plate region 16A is provided with multiple cell regions 17A for displaying an annular image IA (display image), which is the region between a first circle C1 centered at the center point C0 and a second circle C2 having a larger diameter than the first circle C1.

[0043] The light guide plate region 16A is divided circumferentially at predetermined central angles and also divided at predetermined radial intervals, thereby providing each cell region 17A. That is, each cell region 17A is arranged in a matrix in the radial and circumferential directions. In other words, if the radial direction is considered as the column direction and the circumferential direction as the row direction in the matrix, at least one of the row direction and column direction of the cell region 17A has an inclined arrangement portion that, when viewed from a direction perpendicular to the output surface 11a, is inclined with respect to the direction of the optical axis of the light incident from the incident surface 11c and the direction perpendicular to the optical axis.

[0044] Furthermore, the contour of the cell region 17A has an inclined contour portion that, when viewed from a direction perpendicular to the exit surface 11a, is inclined with respect to the direction of the optical axis of the light incident from the incident surface 11c and a direction perpendicular to said optical axis. Specifically, the contour of the cell region 17A has a portion that runs along the circumferential direction centered on the center point C0 and a portion that runs along the radial direction. The portion that runs along the circumferential direction and the portion that runs along the radial direction and is inclined with respect to the direction of the optical axis of the light incident from the incident surface 11c and a direction perpendicular to said optical axis are the inclined contour portions.

[0045] The shape of each cell region 17A is not limited to the shape shown in Figure 6; for example, it may be rectangular. Alternatively, the shape of each cell region 17A may be changed according to the shape of the light deflection section 13 included in the cell region 17A.

[0046] Figure 8 is a plan view showing another example of a light guide plate region in the light guide plate 11 according to the first configuration example, in which multiple cell regions 17B are provided. As shown in Figure 8, the light guide plate region 16B is provided with multiple cell regions 17B for displaying a parallelogram-shaped image IB (display image). The image IB has sides IB1 and IB2 that are parallel to each other, and sides IB3 and IB4 that are parallel to each other but not parallel to sides IB1 and IB2. When viewed from a direction perpendicular to the output surface 11a, sides IB1 and IB2 are inclined with respect to the optical axis of light incident from the incident surface 11c and the direction perpendicular to that optical axis. When viewed from a direction perpendicular to the output surface 11a, sides IB3 and IB4 are perpendicular to the optical axis of light incident from the incident surface 11c. Also, sides IB1 and IB2 are longer than sides IB3 and IB4.

[0047] The light guide plate region 16B has multiple cell regions 17B. The contour of each cell region 17B has a sloping contour portion that is different from that of the cell region 17A. Specifically, the portion of the contour of the cell region 17B that follows sides IB1 and IB2 is the sloping contour portion.

[0048] In the light guide plate region 16A, the outline of an annular image is displayed by the cell region 17A having an inclined contour portion. In the light guide plate region 16B, the outline of a parallelogram-shaped image is displayed by the cell region 17B having an inclined contour portion. Therefore, in the light guide plate regions 16A and 16B, the shape of the pixels that display the outline of the image follows the outline of the image. Consequently, the light guide plate regions 16A and 16B according to this configuration example can reduce distortion in the outline of the displayed image.

[0049] The term "contour" here may refer to the contour of a linear sub-image when images IA and IB are displayed in two or three dimensions. Furthermore, the direction of the contour in the sloping contour portion of cell regions 17A and 17B, or the direction of the array in the sloping array portion, does not need to perfectly match the direction of the image contour; even if there is some deviation, it can reduce distortion in the contour of the displayed image.

[0050] However, the light guide plate according to this example configuration may further include cell regions that do not have inclined contours. In that case, it is not necessary for the entire contour of the image to be displayed by the cell regions that have inclined contours. That is, in the light guide plate according to this example configuration, it is sufficient for at least a portion of the contour of the image to be displayed by the cell regions that have inclined contours. This reduces distortion in the contour of the image compared to the case where the entire contour of the image is displayed by cell regions that do not have inclined contours.

[0051] Furthermore, in the light guide plate region 16A, the inclined contour portion of the cell region 17A is an arc. That is, the inclined contour portion of the cell region 17A is curved. This reduces image distortion where the contour is curved. The inclined contour portion of the cell region 17A may be a curve other than an arc.

[0052] In the light guide plate region 16B, the arrangement direction of the cell region 17B is aligned with the direction of the inclined contour portion. However, the arrangement direction of the cell region 17B does not necessarily have to be aligned with the direction of the inclined contour portion. Even in that case, having an inclined contour portion in the cell region 17B reduces distortion in the image contour compared to a case where there is no inclined contour portion.

[0053] (Configuration example 2) Figure 9 is a plan view showing an example of a light guide plate region in the light guide plate 11 according to the second configuration example, in which multiple cell regions are provided. In Figure 9, reference numeral 901 denotes a plan view showing the configuration of the light guide plate region 16Z in a conventional light guide plate. Reference numeral 902 denotes a plan view showing the configuration of the light guide plate region 16C in the light guide plate of this configuration example.

[0054] In the example shown in Figure 9, the light guide plate region 16Z is provided with multiple cell regions 17Z for displaying a parallelogram-shaped image IB. The light guide plate region 16C is also provided with multiple cell regions 17C for displaying a parallelogram-shaped image IB. As described above, the image IB has two parallel sides IB1 and IB2, and two parallel sides IB3 and IB4 that are not parallel to sides IB1 and IB2. Sides IB1 and IB2 are inclined with respect to the optical axis of light incident from the incident surface 11c, and the direction perpendicular to that optical axis, when viewed from a direction perpendicular to the output surface 11a. Sides IB3 and IB4 are perpendicular to the optical axis of light incident from the incident surface 11c, when viewed from a direction perpendicular to the output surface 11a. Sides IB1 and IB2 are longer than sides IB3 and IB4.

[0055] The light guide plate region 16Z has multiple cell regions 17Z. Furthermore, the light guide plate region 16Z, like the light guide plate 11, includes an exit surface 11a, a back surface 11b, and an incident surface 11c.

[0056] The cell region 17Z has a roughly square shape. The row and column alignment directions of the cell region 17Z are, when viewed from a direction perpendicular to the output surface 11a, the direction of the optical axis of the light incident from the incident surface 11c and the direction perpendicular to said optical axis, respectively. Therefore, the alignment direction of the cell region 17Z coincides with the direction of sides IB3 and IB4, but does not coincide with the direction of sides IB1 and IB2. Consequently, in the image displayed by the light guide plate region 16Z, distortion does not occur in the parts corresponding to sides IB3 and IB4, but distortion occurs in the parts corresponding to sides IB1 and IB2.

[0057] On the other hand, the light guide plate region 16C has a plurality of cell regions 17C. The cell regions 17C, like the cell region 17Z, have a substantially square shape. However, the row and column arrangement directions of the cell regions 17C are inclined with respect to the direction of the optical axis of the light incident from the incident surface 11c and the direction perpendicular to the optical axis, when viewed from a direction perpendicular to the output surface 11a. In other words, the light guide plate region 16C has an inclined arrangement portion composed of a plurality of cell regions 17C that are inclined with respect to the direction of the optical axis of the light incident from the incident surface 11c and the direction perpendicular to the optical axis. In the light guide plate region 16C, the contour of the image is displayed by the cell regions 17C having the inclined contour portion. The magnitude of the inclination may be greater than 0° and less than 90°. In particular, the magnitude of the inclination may be 10° or more and 80° or less.

[0058] Generally, in the case of an image contour, the shorter the distance of the region where the arrangement direction of the cell region is inclined with respect to the contour, and the smaller the inclination, the less noticeable the distortion becomes. In the light guide plate region 16C, the inclination of the arrangement direction of the cell region 17C with respect to sides IB1 and IB2, which are longer than sides IB3 and IB4, is smaller compared to the light guide plate region 16Z. Therefore, the light guide plate region 16C can reduce image distortion compared to the light guide plate region 16Z.

[0059] In particular, in the example shown in Figure 9, the alignment direction of the cell region 17C is aligned with the direction of edges IB1 and IB2, and the direction perpendicular to edges IB1 and IB2. Therefore, the alignment direction of the cell region 17C does not coincide with the direction of edges IB3 and IB4, but it does coincide with the direction of edges IB1 and IB2. Consequently, in the image displayed by the light guide plate region 16C, distortion occurs in the parts corresponding to edges IB3 and IB4, but no distortion occurs in the parts corresponding to edges IB1 and IB2.

[0060] Furthermore, in the example shown by reference numeral 902 in Figure 9, the contours of the individual cell regions 17C are also inclined with respect to the direction of the optical axis of the light incident from the incident surface 11c and the direction perpendicular to the optical axis. Therefore, in the light guide plate region 16C, the entire collection of cell regions 17C is inclined with respect to the direction of the optical axis of the light incident from the incident surface 11c and the direction perpendicular to the optical axis. Such a light guide plate region 16C can be easily manufactured by simply inclining the entire collection of cell regions 17Z in the conventional light guide plate region 16Z.

[0061] In addition, in the light guide plate region 16C, the contours of individual cell regions 17C do not necessarily have to be inclined with respect to the direction of the optical axis of the light incident from the incident surface 11c and the direction perpendicular to said optical axis. Even in that case, if the arrangement direction of the cell regions 17C is inclined with respect to the direction of the optical axis of the light incident from the incident surface 11c and the direction perpendicular to said optical axis, the distortion of the image contour can be reduced more than when the arrangement direction of the cell regions 17C is not inclined with respect to said direction.

[0062] Furthermore, the light guide plate according to this example configuration may also include cell regions that do not constitute the inclined arrangement portion. In that case, it is not necessary for the entire contour of the image to be displayed by the cell regions that constitute the inclined arrangement portion. That is, in the light guide plate according to this example configuration, it is sufficient for at least a portion of the contour of the image to be displayed by the cell regions that constitute the inclined arrangement portion. This reduces distortion of the image contour compared to the case where the entire contour of the image is displayed by cell regions that do not constitute the inclined contour portion.

[0063] (Configuration Example 3) Figure 10 is a plan view showing an example of a light guide plate region in a light guide plate 11 according to the third configuration example, in which multiple cell regions are provided. Multiple cell regions 17D are provided in the light guide plate region 16D shown in Figure 10. In Figure 10, reference numeral 1001 indicates a state in which a parallelogram-shaped image IC (display image) is displayed by the cell regions 17D provided in the light guide plate region 16D. Reference numeral 1002 indicates a state in which a trapezoidal image ID (display image) is displayed by the cell regions 17D provided in the light guide plate region 16D.

[0064] Both the image IC and ID have a shape in which the size in the X-axis direction is larger than the size in the Y-axis direction. The relationship between the size in the X-axis direction and the Y-axis direction of cell region 17D is the same as the relationship between the size in the X-axis direction and the Y-axis direction of the image IC and ID.

[0065] Figure 11 is a plan view showing another example of a light guide plate region in the third configuration example, in which multiple cell regions are provided. The light guide plate region 16E shown in Figure 11 is provided with multiple cell regions 17E. In Figure 11, reference numeral 1101 indicates a state in which a parallelogram-shaped image IE (display image) is displayed by the cell regions 17E provided in the light guide plate region 16E. Reference numeral 1102 indicates a state in which a trapezoidal image IF (display image) is displayed by the cell regions 17E provided in the light guide plate region 16E.

[0066] Both images in images IE and IF have a shape where the size in the Y-axis direction is larger than the size in the X-axis direction. The relationship between the size in the X-axis direction and the Y-axis direction of cell region 17E matches the relationship between the size in the X-axis direction and the Y-axis direction of images IE and IF.

[0067] In Figures 10 and 11, the X-axis direction is referred to as the row direction, and the Y-axis direction as the column direction. In this case, as described above, in the light guide plate regions 16D and 16E, the relationship between the length of the sides of the contours parallel to the row direction and the length of the sides of the contours parallel to the column direction corresponds to the relationship between the size of the displayed image in the row direction and the size of the displayed image in the column direction. As a result, the number of cell regions 17D and 17E increases in the direction in which the displayed image size is larger. That is, the resolution in that direction is improved, and the distortion of the displayed image can be reduced. This configuration example is particularly effective when displaying images that have multiple long contours with different directions, such as the trapezoidal display image shown by reference numerals 1002 and 1102.

[0068] In Figures 10 and 11, cell regions 17D and 17E did not have a slanted contour portion and did not constitute a slanted arrangement portion. However, in the light guide plate according to this configuration example, the aspect ratio of cell regions having a slanted contour portion or constituting a slanted arrangement portion may be made to match the aspect ratio of the image. This further reduces distortion of the outline of the displayed image compared to the case where the aspect ratio of cell regions that do not have a slanted contour portion and do not constitute a slanted arrangement portion is made to match the aspect ratio of the image.

[0069] §3 Variant Example <3.1> Figure 12 is a plan view showing the configuration of the light guide plate region 16F according to the first modified example. The light guide plate region 16F has a first region RA and a second region RB located at a different position from the first region RA. In Figure 12, the first region RA includes multiple cell regions 17A. The second region RB includes multiple cell regions 17B. In the light guide plate region 16F, no cell regions are formed between the first region RA and the second region RB.

[0070] The first region RA and the second region RB have different orientations for the inclined contour portions of the cell regions 17A and 17B contained within them. As a result, the light guide plate region 16F can display both annular and parallelogram-shaped images with reduced distortion.

[0071] Furthermore, in the light guide plate region 16F, the cell regions included in the first region RA and the second region RB may constitute a tilted arrangement portion. In this case, the arrangement directions of the cell regions constituting the tilted arrangement portion in the first region RA and the second region RB may be different from each other. Even in this case, the light guide plate region 16F can display each of the multiple images with reduced distortion.

[0072] <3.2> Figure 13 is a plan view showing the configuration of the light guide plate region 16G according to the second modified example. The light guide plate region 16G displays three annular images and one parallelogram-shaped image. Therefore, the light guide plate region 16G has three first regions RA and one second region RB.

[0073] Furthermore, in the light guide plate region 16G, transition regions RC exist between the first regions RA and between the first region RA and the second region RB. The transition regions RC are regions where cell regions are provided between the first regions RA and between the first region RA and the second region RB, with the arrangement direction and shape gradually changing. In the light guide plate region 16G, cells included in the transition regions RC can also be used for image display.

[0074] Figure 14 is a plan view showing a specific example of the light guide plate region 16G. In Figure 14, two examples of the configuration of the light guide plate region 16H, which is a specific example of the light guide plate region 16G, are shown by reference numerals 1401 and 1402, respectively.

[0075] The light guide plate region 16H displays two parallelogram-shaped images IG and IH (display images) with different degrees of inclination. Image IG includes image IG1 displayed on the emission surface 11a and image IG2 displayed behind the emission surface 11a. Similarly, image IH includes image IH1 displayed on the emission surface 11a and image IH2 displayed behind the emission surface 11a. In the example of reference numeral 1401 and the example of reference numeral 1402, the positions in which images IG2 and IH2 are displayed relative to images IG1 and IH1 are different.

[0076] In both examples, the light guide plate region 16H contains a first region RD where a cell region for displaying image IG1 is formed, and a second region RE where a cell region for displaying image IH1 is formed. A transition region RF exists between the first region RD and the second region RE.

[0077] In reference numeral 1401, image IG2 is displayed between image IG1 and image IH1. In this case, the cell area for displaying image IG2 is located in the transition area RF. On the other hand, image IH2 is displayed on the opposite side of image IH1 from image IG1. Therefore, the cell area for displaying image IH2 is located in the second area RE.

[0078] In reference numeral 1402, image IH2 is displayed between image IG1 and image IH2. Therefore, the cell area for displaying image IH2 is located in the transition area RF. On the other hand, image IG2 is displayed on the opposite side of image IG1 from image IH1. Therefore, the cell area for displaying image IG2 is located in the first area RD.

[0079] As described above, in the light guide plate region 16H, a cell region for displaying image IG2 or image IH2 is arranged in the transition region RF. Since images IG2 and IH2 give a sense of depth to images IG and IH, they do not need to strictly match the contours of image IG1 or image IH1. For this reason, the shape of image IG2 or image IH2 may be appropriately changed so that distortion caused by the shape of the cell region provided in the transition region RF is not noticeable. Thus, the light guide plate region 16H reduces distortion in the contours of the images and makes effective use of the transition region RF.

[0080] <3.3> As a third modification, a light guide plate 18 different from the light guide plate 11 in the above application example will be described below.

[0081] Figure 15 is a plan view of a light guide plate 18 according to a third modified example. The light guide plate 18, like the light guide plate 11, has an exit surface 11a, a back surface 11b, and an incident surface 11c. As shown in Figure 15, the back surface 11b of the light guide plate 18 has multiple cell regions 19a, 19b, 19c… each provided with multiple light deflection sections 13. Each of the light deflection sections 13 in cell region 19a reflects light in a different direction from each other. Each of the light deflection sections 13 in cell region 19b reflects light in a different direction from each other. Each of the light deflection sections 13 in cell region 19c reflects light in a different direction from each other. In the example shown in Figure 15, the light deflection sections 13 in each of the cell regions 19a, 19b, 19c… are provided in a straight line along a direction parallel to the incident surface 11c.

[0082] Figure 16 is a perspective view showing the arrangement of the light deflection units 13. As shown in Figure 16, in each cell region 19a, 19b, 19c..., the reflective surfaces 14 of the multiple light deflection units 13 are arranged on the back surface 11b of the light guide plate 18 such that their angles with respect to the direction of light incidence are different from each other. As a result, each cell region 19a, 19b, 19c... reflects the incident light and emits it from the emission surface 11a in various directions.

[0083] Next, the method of imaging image II (display image) using the light guide plate 18 will be explained with reference to Figure 17. Here, we will explain the case in which image II as a surface image is formed on the three-dimensional image imaging surface P, which is a surface perpendicular to the emission surface 11a of the light guide plate 18, by light whose optical path has been changed by the light deflection unit 13.

[0084] Figure 17 is a perspective view showing the imaging method of Image II using the light guide plate 18. Here, we will explain how to image a ring mark with diagonal lines as Image II on the three-dimensional image imaging surface P.

[0085] In the light guide plate 18, as shown in Figure 17, for example, the light whose optical path has been changed by each light deflection unit 13 in the cell region 19a intersects the stereoscopic image imaging plane P with lines La1 and La2. This causes the line image LI, which is part of image II, to be imaged on the stereoscopic image imaging plane P. The line image LI is a line image parallel to the XZ plane. In this way, the line images LI of lines La1 and La2 are imaged by light from a number of light deflection units 13 belonging to the cell region 19a. Note that the light that images the lines La1 and La2 only needs to be provided by at least two light deflection units 13 in the cell region 19a.

[0086] Similarly, the light whose optical path has been altered by each light deflection unit 13 in the cell region 19b intersects the stereoscopic image imaging plane P with lines Lb1, Lb2, and Lb3. This causes the line image LI, which is part of image II, to be imaged onto the stereoscopic image imaging plane P.

[0087] Furthermore, the light whose optical path has been altered by each light deflection unit 13 in the cell region 19c intersects the stereoscopic image imaging plane P with lines Lc1 and Lc2. This causes the line image LI, which is part of image II, to be imaged onto the stereoscopic image imaging plane P.

[0088] The line images LI formed by each cell region 19a, 19b, 19c… are positioned differently in the X-axis direction. The light guide plate 18 can reduce the distance in the X-axis direction of the line images LI formed by each cell region 19a, 19b, 19c… by reducing the distance between the cell regions 19a, 19b, 19c…. As a result, the light guide plate 18 integrates the multiple line images LI formed by the light whose optical path has been changed by the light deflection sections 13 of each cell region 19a, 19b, 19c…, thereby forming an image II, which is essentially a planar image, on the stereoscopic image imaging plane P.

[0089] 〔summary〕 This invention can also be expressed as follows.

[0090] A light guide plate according to Embodiment 1 of the present invention is a light guide plate that displays a display image which is a predetermined planar image or a three-dimensional image using a plurality of pixels, comprising: an incident surface into which light from a light source is incident; an exit surface from which the light is emitted; and a plurality of light deflection portions that reflect the light incident from the incident surface and guided, causing the light to be emitted from the exit surface, wherein a plurality of cell regions, each having one or more of the light deflection portions, are arranged in a matrix, and at least one of the following is true: (1) At least one of the row-direction arrangement direction and the column-direction arrangement direction of the cell regions has an inclined arrangement portion composed of a plurality of cell regions that, when viewed from a direction perpendicular to the exit surface, is inclined with respect to the direction of the optical axis of the light incident from the incident surface and a direction perpendicular to the optical axis; and (2) The contour of the cell region has an inclined contour portion that, when viewed from a direction perpendicular to the exit surface, is inclined with respect to the direction of the optical axis of the light incident from the incident surface and a direction perpendicular to the optical axis.

[0091] In the light guide plate according to embodiment 2 of the present invention, in embodiment 1, the cell region is provided with a plurality of light deflection portions that reflect the light in different directions from each other.

[0092] In the light guide plate according to embodiment 3 of the present invention, in embodiment 1 or 2, at least a portion of the outline of the display image is displayed by the cell region constituting the inclined arrangement portion.

[0093] In the light guide plate according to embodiment 4 of the present invention, in embodiment 1 or 2, at least a portion of the outline of the display image is displayed by the cell region having the inclined contour portion.

[0094] In the light guide plate according to embodiment 5 of the present invention, in any of embodiments 1 to 4, the relationship between the length of the side of the contour parallel to the row direction of the cell region and the length of the side of the contour parallel to the column direction is the same as the relationship between the size of the display image in the row direction and the size of the display image in the column direction.

[0095] In the light guide plate according to embodiment 6 of the present invention, in any of embodiments 1 to 5, at least one of the arrangement of the plurality of cell regions constituting the inclined arrangement portion and the inclined contour portion is curved.

[0096] A light guide plate according to embodiment 7 of the present invention has, in any of embodiments 1 to 6, a first region including a plurality of cell regions and a second region including a plurality of cell regions located at a different position from the first region, wherein at least one of the arrangement direction of the plurality of cell regions constituting the inclined arrangement portion and the direction of the inclined contour portion are different between the first region and the second region.

[0097] A display device according to embodiment 8 of the present invention comprises a light guide plate according to any of embodiments 1 to 7 and the light source.

[0098] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of Symbols]

[0099] 10 Display device 11, 18 Light guide plate 11a Output surface 11b Back 11c Incidence plane 13 Light deflection section Cell areas 15, 15a, 15b, 15c, 15d, 15e, 15f, 15g, 17A, 17B, 17C, 17D, 17E, 19a, 19b, 19c

Claims

1. A light guide plate that displays a display image, which is a predetermined planar or three-dimensional image, using multiple pixels, The incident surface into which light from the light source enters, The light is emitted from the emission surface, The system comprises a plurality of light deflection units that reflect the light incident on the incident surface and guided by light, thereby causing the light to be emitted from the exit surface, Multiple cell regions, each having one or more of the aforementioned light deflection sections, are arranged in a matrix. (1) At least one of the row-direction and column-direction arrangement directions of the cell regions has an inclined arrangement portion composed of a plurality of cell regions, which, when viewed from a direction perpendicular to the output surface, is inclined with respect to the direction of the optical axis of the light incident from the incident surface and a direction perpendicular to said optical axis, and, (2) The contour of the cell region has at least one of the following: the contour of the cell region is inclined with respect to the direction of the optical axis of the light incident from the incident surface and the direction perpendicular to the optical axis, when viewed from a direction perpendicular to the exit surface, and the contour of the cell region is inclined with respect to the direction of the optical axis. A light guide plate in which at least a portion of the outline of the display image is displayed by at least one of the cell regions constituting the inclined arrangement portion and the cell regions having the inclined contour portion.

2. The light guide plate according to claim 1, wherein the cell region is provided with a plurality of light deflection portions that reflect the light in different directions from each other.

3. The light guide plate according to claim 1, wherein the relationship between the length of the side of the contour parallel to the row direction of the cell region and the length of the side of the contour parallel to the column direction is such that the relationship between the size of the display image in the row direction and the size of the display image in the column direction is the same.

4. The light guide plate according to claim 1, wherein at least one of the arrangement of the plurality of cell regions constituting the inclined arrangement portion and the inclined contour portion is curved.

5. It comprises a first region containing a plurality of the aforementioned cell regions, and a second region containing a plurality of the aforementioned cell regions, which is located at a different position from the first region. The light guide plate according to claim 1, wherein in the first region and the second region, at least one of the arrangement directions of the plurality of cell regions constituting the inclined arrangement portion and the direction of the inclined contour portion are different from each other.

6. A light guide plate according to any one of claims 1 to 5, A display device comprising the aforementioned light source.

Images