Display device

Abstract

The display device includes: a light source; and a transparent and flat-plate-shaped light guide body on which light emitted from the light source is incident from the first side surface, the light guide body having, at each of a plurality of positions corresponding to the plurality of symbols, a reflection section comprising a plurality of reflection surfaces inclined with respect to the bottom surface, the light guide body reflecting the light incident from the first side surface by means of each of the plurality of reflection sections by means of the plurality of reflection surfaces, the closer the reflection part is to the light source, the smaller the inclination angle of the reflection surface relative to the bottom surface is.

Description

Technical Field

[0001] The present invention relates to a display device. Background Art

[0002] In the following Patent Document 1, a technology is disclosed regarding a light guide plate display device that is capable of displaying a pattern on a display surface of a light guide by utilizing the reflective slope of a prism to reflect light that is irradiated from a light source device toward the side of the light guide and incident into the interior of the light guide, namely, in order to balance the brightness of the pattern display, the area of ​​the reflective slope of the prism at a position farther from the light source device is made larger than the area of ​​the reflective slope of the prism at a position closer to the light source device.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-53605 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, the technology of Patent Document 1 displays a plurality of pattern displays with different areas of each prism, which may give a user who visually recognizes the plurality of pattern displays a sense of discomfort.

[0008] Solutions to Solve Problems

[0009] A display device in one embodiment comprises: a light source; and a transparent and flat light guide, on which light emitted from the light source is incident from a first side surface, the light guide having a reflecting portion composed of a plurality of reflecting surfaces inclined relative to a bottom surface at a plurality of positions corresponding to a plurality of symbols, the light guide reflects the light incident from the first side surface using the plurality of reflecting surfaces through the plurality of reflecting portions, thereby displaying a plurality of symbols on a display surface, and the closer the reflecting portion is to the light source, the smaller the inclination angle of the reflecting surface relative to the bottom surface.

[0010] Effects of the Invention

[0011] According to one embodiment, a plurality of symbols can be displayed on the display surface of the light guide with uniform brightness without adjusting the area of ​​the reflection portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a top view of a display device according to one embodiment.

[0013] Figure 2 This is a side view of a display device according to one embodiment.

[0014] Figure 3A This is an enlarged view of a reflective surface included in a display device according to an embodiment.

[0015] Figure 3B This is an enlarged view of a reflective surface included in a display device according to an embodiment.

[0016] Figure 4A This is a diagram showing the relationship between the inclination angle of the reflection surface and the brightness of the symbol in the display device according to one embodiment.

[0017] Figure 4B This is a diagram showing the relationship between the inclination angle of the reflection surface and the brightness of the symbol in the display device according to one embodiment.

[0018] Figure 5 It is a side view of the display device of the first modification example.

[0019] Figure 6 It is a side view of a display device according to a second modification. DETAILED DESCRIPTION

[0020] Hereinafter, an embodiment is described with reference to the accompanying drawings. It should be noted that, in the following description, for convenience, the Z-axis direction in the figure is set as the up-down direction, the Y-axis direction in the figure is set as the left-right direction, and the X-axis direction in the figure is set as the front-back direction. Among them, the positive direction of the Z-axis is set as the top, the positive direction of the Y-axis is set as the right, and the positive direction of the X-axis is set as the front.

[0021] (Structure of Display Device 100 )

[0022] Figure 1 It is a top view of a display device 100 according to an embodiment. Figure 2 FIG. 1 is a side view of a display device 100 according to an embodiment. Figure 1 as well as Figure 2 As shown, the display device 100 includes a light guide 110 and a light source 120 .

[0023] The light guide 110 is a transparent, flat member. The light guide 110 is formed by using a transparent resin raw material. Figure 1 As shown, the light guide 110 has a rectangular shape with the left-right direction (Y-axis direction) as the length direction when viewed from above (Z-axis positive direction). Figure 2 As shown, the light guide 110 is a flat plate having a constant thickness in the vertical direction (Z-axis direction). The light guide 110 includes a display surface 111 , a bottom surface 112 , a first side surface 113 , and a plurality of reflection portions 130 .

[0024] The display surface 111 is the upper surface of the light guide 110 (the horizontal surface on the positive side of the Z axis). When the light source 120 emits light, a plurality of symbols are displayed on the display surface 111. Figure 1In the example shown, when the light source 120 emits light, the symbol S1 and the symbol S2 are displayed in the left-right direction (Y-axis direction) on the display surface 111. The symbol S1 is displayed in the area to the left of the center (the negative side of the Y axis) of the display surface 111. The symbol S2 is displayed in the area to the right of the center (the positive side of the Y axis) of the display surface 111. Figure 1 In the example, symbol S1 is a character "X". Also, symbol S2 is a character "Y".

[0025] The bottom surface 112 is the bottom surface of the light guide 110 (a horizontal surface on the negative side of the Z axis). The bottom surface 112 is parallel to the display surface 111. A plurality of reflection parts 130 are provided on the bottom surface 112.

[0026] The first side surface 113 is the left side surface (the side surface on the negative side of the Y axis (vertical surface)) of the light guide 110 . The first side surface 113 faces the light source 120 and allows light emitted from the light source 120 to enter the light guide 110 .

[0027] The plurality of reflective portions 130 are respectively disposed on the bottom surface 112 of the light guide 110 and at positions corresponding to the plurality of symbols. Figure 2 In the example shown, two reflection parts 130-1 and 130-2 are arranged in the left-right direction (Y-axis direction) on the bottom surface 112 of the light guide 110 in correspondence with the two symbols S1 and S2 displayed on the display surface 111. The reflection part 130-1 is provided on the bottom surface 112 of the light guide 110 at a position corresponding to the symbol S1 (directly below the symbol S1). The reflection part 130-2 is provided on the bottom surface 112 of the light guide 110 at a position corresponding to the symbol S2 (directly below the symbol S2).

[0028] Each of the reflection parts 130-1 and 130-2 has a plurality of reflection surfaces 131 inclined relative to the bottom surface 112. Each of the plurality of reflection surfaces 131 is inclined toward the first side surface 113 and can reflect light propagating from the first side surface 113 in the light guide 110 upward (in the positive direction of the Z axis).

[0029] The plurality of reflecting surfaces 131 are arranged on the bottom surface 112 so that the overall shape is the same as the shape of the corresponding symbol when viewed from above (in the positive direction of the Z axis). In other words, the plurality of reflecting surfaces 131 are densely arranged within the range surrounded by the outer shape of the symbol. Thus, the plurality of reflecting surfaces 131 can reflect the reflected light whose overall shape is the same as the shape of the corresponding symbol when viewed from above (in the positive direction of the Z axis) upward (in the positive direction of the Z axis), so that it is visually recognized as the shape of the symbol.

[0030] For example, each of the plurality of reflective surfaces 131 is formed on the bottom surface 112 by forming a recess 133 that is recessed upward (in the positive direction of the Z axis) relative to the bottom surface 112 of the light guide 110 and has a triangular cross-section when viewed from the front-to-back direction (in the X axis direction).

[0031] The light source 120 is arranged on the left side (the side on the negative side of the Y axis) of the first side surface 113 of the light guide 110 so as to face the first side surface 113. The light source 120 is driven by a driving circuit (not shown) to emit light toward the right (positive direction of the Y axis), thereby irradiating the light toward the first side surface 113 of the light guide 110. Thus, the light source 120 injects light into the light guide 110 from the first side surface 113 of the light guide 110. For example, an LED (Light Emitting Diode) is used as the light source 120.

[0032] (Display Function of Display Device 100)

[0033] When the light source 120 of the display device 100 configured as above is driven to emit light, the light emitted from the light source 120 enters the light guide 110 from the first side surface 113 of the light guide 110. Most of the light entering the light guide 110 propagates while being totally reflected in the light guide 110.

[0034] A portion of the light propagating in the light guide 110 is reflected upward (in the positive direction of the Z axis) by the plurality of reflection surfaces 131 provided in the reflection unit 130-1, and is emitted upward (in the positive direction of the Z axis) from the display surface 111 of the light guide 110 while maintaining the same overall shape as the shape of the symbol S1 when viewed from above (in the positive direction of the Z axis). As a result, the symbol S1 is displayed on the display surface 111 of the light guide 110, and the symbol S1 can be visually confirmed from above (in the positive direction of the Z axis).

[0035] In addition, another part of the light propagating in the light guide 110 is reflected upward (in the positive direction of the Z axis) by the multiple reflection surfaces 131 provided in the reflection part 130-2, and is emitted upward (in the positive direction of the Z axis) from the display surface 111 of the light guide 110 while maintaining the overall shape that is the same as the shape of the symbol S2 when viewed from above (in the positive direction of the Z axis). As a result, the symbol S2 is displayed on the display surface 111 of the light guide 110, so that the symbol S2 can be visually confirmed from above (in the positive direction of the Z axis).

[0036] (Inclination angle of the reflecting surface 131)

[0037] FIG. 3 is an enlarged view of a reflective surface 131 included in the display device 100 according to an embodiment. Figure 3A One of the plurality of reflecting surfaces 131 included in the reflecting unit 130 - 1 is representatively shown. Figure 3B One of the plurality of reflecting surfaces 131 included in the reflecting unit 130 - 2 is representatively shown.

[0038] In the display device 100 according to one embodiment, the closer the reflective portion 130 is to the light source 120 , the smaller the inclination angle of the reflective surface 131 with respect to the bottom surface 112 .

[0039] For example, in Figure 2 In the example shown, the reflection part 130 - 1 is closer to the light source 120 than the reflection part 130 - 2. Therefore, as shown in FIG. 3 , the inclination angle θ1 of the plurality of reflection surfaces 131 of the reflection part 130 - 1 is smaller than the inclination angle θ2 of the plurality of reflection surfaces 131 of the reflection part 130 - 2.

[0040] As a result, the direction of the reflected light with the maximum light amount is offset from the vertical direction. In one embodiment of the display device 100, the component of the light amount reflected by the multiple reflecting surfaces 131 toward the direction of the symbol S1 (upward and vertical direction) in the light irradiated to the reflecting portion 130-1 (that is, the light emitted from the display surface 111 to display the symbol S1) can be less than the case where the direction of the reflected light with the maximum light amount is set to the vertical direction.

[0041] On the other hand, in a display device 100 according to one embodiment, the direction of the reflected light with the largest amount of light in the reflecting portion 130-2 farther from the light source 120 is set to a vertical direction, thereby increasing the component of the amount of light reflected by the plurality of reflecting surfaces 131 in the direction of the symbol S2 (upward and vertical direction) in the light irradiated to the reflecting portion 130-2 (i.e., light emitted from the display surface 111 to display the symbol S2).

[0042] It should be noted that, with respect to the amount of light, the amount of light that is maximum in a prescribed direction tends to decrease when it is deviated from the prescribed direction, and the direction in which the amount of light will be maximum in the reflecting portion 130-2 is set to a vertical direction, but the direction in which the amount of light will be maximum in the reflecting portion 130-1 is deviated toward the direction opposite to the light source, so that the inclination angle θ1 is smaller than the inclination angle θ2.

[0043] Here, in a display device 100 of one embodiment, in the reflection portion 130-1 that is closer to the light source 120, the amount of light irradiated to the reflection portion 130-1 is relatively large because it is closer to the light source 120 (the attenuation is small because the number of total reflections is small). In this state, the brightness of the symbol S1 is relatively high, but the inclination angle θ1 of the reflection surface 131 is set as described above so that the amount of reflected light reflected by the reflection surface 131 is relatively small, thereby enabling the brightness of the symbol S1 to be reduced to an appropriate amount.

[0044] On the other hand, in the display device 100 of one embodiment, in the reflection part 130-2 farther from the light source 120, the amount of light irradiated to the reflection part 130-2 is relatively small due to the farther distance from the light source 120 (the attenuation is greater due to the greater number of total reflections). In this state, the brightness of the symbol S2 is relatively low, but the inclination angle θ2 of the reflection surface 131 is set as described above to maximize the amount of light reflected by the reflection surface 131, thereby increasing the brightness of the symbol S2.

[0045] Therefore, according to the display device 100 of one embodiment, it is possible to suppress the brightness difference between the brightness of the symbol S1 and the brightness of the symbol S2 displayed on the display surface 111 of the light guide 110. Therefore, according to the display device 100 of one embodiment, it is possible to display a plurality of symbols on the display surface 111 of the light guide 110 in a manner that the brightness becomes uniform without adjusting the area of ​​the reflection part 130.

[0046] It should be noted that in this embodiment, as an example, the multiple reflection surfaces 131 of each reflection portion 130 - 1 and 130 - 2 have the same inclination angle, but this is not limited to this. The multiple reflection surfaces 131 of any reflection portion 130 - 1 and 130 - 2 can also be set to have different inclination angles according to the distance from the light source 120.

[0047] (Projection area of ​​the reflecting surface 131)

[0048] In the display device 100 according to one embodiment, the projection areas of the respective reflection surfaces 131 are equal among the plurality of reflection portions 130 when viewed from above the display surface 111 side of the light guide 110 .

[0049] For example, as shown in FIG3 , the reflection surface 131 of the reflection unit 130-1 and the reflection surface 131 of the reflection unit 130-2 have different inclination angles, but the width Y1 of the reflection surface 131 of the reflection unit 130-1 in the left-right direction (Y-axis direction) and the width Y2 of the reflection surface 131 of the reflection unit 130-2 in the left-right direction (Y-axis direction) are equal to each other. It should be noted that, although not shown in the figure, the width of the reflection surface 131 of the reflection unit 130-1 in the front-back direction (X-axis direction) and the width of the reflection surface 131 of the reflection unit 130-2 in the front-back direction (X-axis direction) are equal to each other.

[0050] Therefore, the projection areas of the reflection surface 131 of the reflection unit 130-1 and the reflection surface 131 of the reflection unit 130-2 are equal when viewed from the display surface 111 side (Z-axis positive side) of the light guide 110. In addition, the multiple reflection surfaces 131 of the reflection unit 130-1 and the multiple reflection surfaces 131 of the reflection unit 130-2 are formed at equal intervals and at equal density when viewed from the display surface 111 side (Z-axis positive side) of the light guide 110.

[0051] Therefore, according to the display device 100 of one embodiment, when the light source 120 is not lit, the difference in apparent brightness between the symbol S1 and the symbol S2 displayed on the display surface 111 of the light guide 110 caused by the projection area of ​​the reflective surface 131 can be suppressed. That is, when the light source 120 is not lit, there is a case where the reflective surface 131 reflects external light and the surface of the reflective surface 131 looks whitish. When the projection areas when viewed from the display surface 111 side (Z-axis positive side) of the reflective surface 131 are different, each reflective surface 131 itself is very fine, so there is almost no direct visual confirmation, but when observing the symbol as a whole, the difference in apparent brightness can be seen. However, according to the display device 100 of one embodiment, the projection areas of each reflective surface 131 are equal among the multiple symbols displayed on the display surface 111 of the light guide 110, so that the user who visually confirms the multiple symbols will not feel uncoordinated.

[0052] It should be noted that, in the present embodiment, the reflection surface 131 of the reflection unit 130-1 and the reflection surface 131 of the reflection unit 130-2 are made equal in projected area, but instead of this, the reflection surface 131 of the reflection unit 130-1 and the reflection surface 131 of the reflection unit 130-2 may be made equal in actual area. In this case, although the reflection surface 131 of the reflection unit 130-1 and the reflection surface 131 of the reflection unit 130-2 have different projected areas, for example, the reflection surfaces 131 can be arranged more densely by reducing the projected areas.

[0053] (Setting Example of the Inclination Angle of the Reflection Surface 131)

[0054] 4 is a diagram showing the relationship between the tilt angle of the reflection surface 131 and the brightness in the positive Z-axis direction (upward and vertical direction) of the symbol in the display device 100 according to one embodiment, and shows the results obtained by simulation.

[0055] In the display device 100 of one embodiment, the inclination angle of the reflection surface 131 of each of the plurality of reflection portions 130 - 1 and 130 - 2 is set so that the brightness of the plurality of symbols displayed on the display surface 111 of the light guide 110 is equal.

[0056] Figure 4A It is a graph showing the relationship between the inclination angle of the reflection surface 131 included in the reflection unit 130 - 1 and the brightness of the symbol S1 displayed on the display surface 111 . Figure 4B : is a graph showing the relationship between the inclination angle of the reflection surface 131 included in the reflection unit 130 - 2 and the brightness of the symbol S2 displayed on the display surface 111 .

[0057] It should be noted that, in the graph shown in FIG. 4 , the inclination angle of the horizontal axis means the inclination angle of the reflection surface 131 with respect to the bottom surface 112 .

[0058] like Figure 4B As shown, in the reflection portion 130 - 2 which is far from the light source 120 , an inclination angle D21 at which the brightness of the symbol S2 becomes maximum is set as the inclination angle θ2 of the plurality of reflection surfaces 131 .

[0059] Thus, the inclination angles of the plurality of reflection surfaces 131 are set so that the maximum brightness is obtained when the symbol S2 corresponding to the reflection portion 130 - 2 (ie, the reflection portion 130 farthest from the light source 120 ) is visually recognized from the display surface 111 side.

[0060] On the other hand, Figure 4A As shown, in the reflection portion 130 - 1 closer to the light source 120 , an inclination angle D13 at which the brightness of the symbol S1 is equal to the brightness of the symbol S2 is set as the inclination angle θ1 of the plurality of reflection surfaces 131 .

[0061] However, if Figure 4A As shown, in the reflection surface 131 of the reflection unit 130-1, there are two inclination angles D11 and D13, with the inclination angle D12 at which the brightness of the symbol S1 is the maximum being sandwiched between the inclination angles at which the brightness of the symbol S1 is equal to the brightness of the symbol S2. Figure 4A As shown, a smaller inclination angle D13 is set as the inclination angle θ1 of the plurality of reflection surfaces 131 .

[0062] This is to minimize the effect of the dimensional error of the tilt angle. Figure 4AAs shown, for the slope of the curve showing the relationship between the inclination angle of the reflecting surface 131 and the brightness of the symbol S1, the slope of the inclination angle D11 is larger than the slope of the inclination angle D13. Therefore, even if the inclination angle deviates from the reference angle due to processing and setting, the influence of the inclination angle D13 on the change in brightness is small. It is expected that this is because the light emitted from the light source 120 is light toward the positive side of the Y axis. When the inclination angle of the reflecting surface increases, the incident angle (reflection angle) of the light relative to the reflecting surface tends to become smaller. If the incident angle is small, the light is not totally reflected and emitted, so the brightness changes significantly. On the other hand, when the angle of the reflecting surface is small, the reflection angle of the light relative to the reflecting surface tends to become larger, and the light that is totally reflected remains in a totally reflected state, so the brightness does not change significantly.

[0063] As described above, the display device 100 according to one embodiment can easily make the brightness of the symbol S1 and the brightness of the symbol S2 displayed on the display surface 111 of the light guide 110 equal.

[0064] It should be noted that the preferred inclination angles θ1 and θ2 of the reflection surface 131 can be obtained by a predetermined calculation formula, simulation, or the like.

[0065] (First Modification)

[0066] Below, refer to Figure 5 A first modified example of the display device 100 according to the embodiment will be described. Figure 5 It is a side view of a display device 100 - 2 according to a first modification.

[0067] like Figure 5 As shown, the display device 100 - 2 of the first modification example includes a reflection section 130 - 1 , a reflection section 130 - 2 , and a reflection section 130 - 3 in order from the light source 120 side (Y-axis negative side) as an example of a plurality of reflection sections 130 .

[0068] The reflecting unit 130 - 1 causes the display surface 111 of the light guide 110 to display a symbol S1. The reflecting unit 130 - 2 causes the display surface 111 of the light guide 110 to display a symbol S2. The reflecting unit 130 - 3 causes the display surface 111 of the light guide 110 to display a symbol S3.

[0069] Each of the reflection parts 130 - 1 , 130 - 2 , and 130 - 3 has a plurality of reflection surfaces 131 on the bottom surface 112 of the light guide 110 and faces the first side surface 113 (the negative side of the Y axis). Figure 5 In FIG. 1 , for convenience, one of the plurality of reflection surfaces 131 included in the reflection units 130 - 1 , 130 - 2 , and 130 - 3 is representatively shown.

[0070] In addition, if Figure 5 As shown, in the display device 100-2 of the first modified example, the light guide 110 has a side reflector 115 on the second side surface 114 which is the surface on the side opposite to the first side surface 113. The side reflector 115 is provided in a manner covering the entire area of ​​the second side surface 114. The side reflector 115 reflects the light irradiated to the second side surface 114 of the light propagating inside the light guide 110 toward the inside of the light guide 110. Thus, the display device 100-2 of the first modified example can also irradiate the reflectors 130-1, 130-2, and 130-3 from the second side surface 114 side (positive side of the Y axis), and can improve the brightness of each symbol on the display surface 111. It should be noted that as the side reflector 115, for example, an aluminum reflector sheet, a white reflector sheet, a white paint, etc. are used.

[0071] In addition, if Figure 5 As shown, in the display device 100 - 2 of the first modification, each of the reflection parts 130 - 1 , 130 - 2 , and 130 - 3 is integrally formed with the plurality of reflection surfaces 131 and has a second reflection surface 132 facing the side reflection part 115 side (Y-axis positive side).

[0072] Here, in the display device 100 - 2 of the first modification example, the closer the reflective portion 130 is to the first side surface 113 , the smaller the inclination angle of the reflective surface 131 with respect to the bottom surface 112 of the light guide 110 .

[0073] Therefore, in the display device 100-2 of the first variant example, the closer the reflecting portion 130 is to the first side surface 113, the greater the amount of light irradiated from the first side surface 113 side (negative side of the Y axis) due to its proximity to the light source 120, but the amount of light reflected by the multiple reflecting surfaces 131 in the direction of the symbol (upward and vertical direction) among the light irradiated from the first side surface 113 side (negative side of the Y axis) (i.e., light emitted from the display surface 111 to display the symbol) can be relatively small.

[0074] In the display device 100 - 2 of the first modification, the closer the reflection portion 130 is to the side reflection portion 115 , the smaller the inclination angle of the second reflection surface 132 with respect to the bottom surface 112 of the light guide 110 .

[0075] Thus, in the display device 100-2 of the first variant, the closer the reflecting portion 130 is to the side reflecting portion 115, the greater the amount of light irradiated from the side reflecting portion 115 side (positive side of the Y axis) due to its proximity to the side reflecting portion 115, but the amount of light reflected by the plurality of second reflecting surfaces 132 toward the direction of the symbol (upward and vertical direction) among the light irradiated from the side reflecting portion 115 side (positive side of the Y axis) (i.e., light emitted from the display surface 111 to display the symbol) can be made relatively small.

[0076] For example, since the distance L1 between the reflecting portion 130-1 and the first side surface 113 is short, the amount of light irradiated from the first side surface 113 side (the negative side of the Y axis) is relatively large, but the inclination angle of the reflecting surface 131 relative to the bottom surface 112 is relatively small, so the amount of reflected light reflected by the reflecting surface 131 in the direction of the symbol S1 (upward and vertical direction) is relatively small, so the brightness of the symbol S1 displayed on the display surface 111 can be made appropriate.

[0077] In addition, since the distance L3' between the reflecting portion 130-1 and the side reflecting portion 115 is long, the amount of light irradiated from the side reflecting portion 115 side (positive side of the Y axis) is relatively small, but the inclination angle of the second reflecting surface 132 is relatively large, so the amount of reflected light reflected by the second reflecting surface 132 in the direction of the symbol S1 (upward and vertical direction) is relatively large, and therefore the brightness of the symbol S1 displayed on the display surface 111 is appropriate.

[0078] In addition, for example, since the distance L2 between the reflecting portion 130-2 and the first side surface 113 is medium, the amount of light irradiated from the first side surface 113 side (negative side of the Y axis) is medium, but the inclination angle of the reflecting surface 131 relative to the bottom surface 112 is medium, the amount of reflected light reflected by the reflecting surface 131 in the direction of the symbol S2 (upward and vertical direction) can be set to medium, and thus the brightness of the symbol S2 displayed on the display surface 111 can be set to an appropriate amount.

[0079] In addition, since the distance L2' between the reflecting portion 130-2 and the side reflecting portion 115 is medium, the amount of light irradiated from the side reflecting portion 115 side (positive side of the Y axis) is medium, but the inclination angle of the second reflecting surface 132 is medium, so the amount of light reflected by the second reflecting surface 132 in the direction of the symbol S2 (upward and vertical direction) can be set to medium, and thus the brightness of the symbol S2 displayed on the display surface 111 can be set to an appropriate amount.

[0080] In addition, for example, since the distance L3 between the reflecting portion 130-3 and the first side surface 113 is long, the amount of light irradiated from the first side surface 113 side (the negative side of the Y axis) is relatively small, but the inclination angle of the reflecting surface 131 relative to the bottom surface 112 is relatively large, so the amount of reflected light reflected by the reflecting surface 131 in the direction of the symbol S1 (upward and vertical direction) can be relatively large, so the brightness of the symbol S3 displayed on the display surface 111 can be set to an appropriate level.

[0081] In addition, since the distance L1' between the reflection part 130-3 and the side reflection part 115 is short, the amount of light irradiated from the side reflection part 115 side (positive side of the Y axis) is relatively large, but since the inclination angle of the second reflection surface 132 is relatively small, the amount of reflected light reflected by the second reflection surface 132 in the direction of the symbol S1 (upward and vertical direction) can be relatively small, so the brightness of the symbol S3 displayed on the display surface 111 can be set to an appropriate amount.

[0082] As described above, the display device 100 according to the first modification example can easily make the brightness of the symbol S1 , the brightness of the symbol S2 , and the brightness of the symbol S3 displayed on the display surface 111 of the light guide 110 equal.

[0083] It should be noted that the display device 100 of the first modification example has a symmetrical structure of the light guide 110 in the left-right direction (Y-axis direction) in order to achieve uniform brightness of symbols on the display surface 111 when the light source 120 is not turned on.

[0084] Specifically, the distance L1 between the reflector 130-1 and the first side surface 113 is equal to the distance L1' between the reflector 130-3 and the side reflector 115. In addition, the inclination angle of the reflective surface 131 of the reflector 130-1 is equal to the inclination angle of the second reflective surface 132 of the reflector 130-3. In addition, the inclination angle of the second reflective surface 132 of the reflector 130-1 is equal to the inclination angle of the reflective surface 131 of the reflector 130-3.

[0085] In addition, the distance L2 between the reflector 130-2 and the first side surface 113 is equal to the distance L2' between the reflector 130-2 and the side reflector 115. In addition, the inclination angle of the reflective surface 131 of the reflector 130-2 is equal to the inclination angle of the second reflective surface 132 of the reflector 130-2.

[0086] Therefore, the width W of the concave portion 133 formed by the adjacent reflecting surface 131 and the second reflecting surface 132 is equal in the reflecting portions 130-1, 130-2, and 130-3. Therefore, the projection area of ​​the concave portion 133 onto the XY plane can be made the same. Therefore, the size of the concave portion 133 can be made the same in all symbols, and the spacing (configuration density) of the configuration can be made constant, so the brightness of each symbol when the light source 120 is not lit can be made constant.

[0087] It should be noted that in Figure 5 In the example shown, the reflecting surface 131 and the second reflecting surface 132 are configured to be triangular (prism) shaped, but the present invention is not limited thereto. The reflecting surface 131 and the second reflecting surface 132 may be configured to be other shapes (eg, a crescent cut shape, etc.).

[0088] In addition, in the display device 100 of the first modification, a second light source (for example, LED) may be provided instead of the side reflection unit 115. In this case, the display device 100-2 of the first modification can also irradiate the reflection units 130-1, 130-2, and 130-3 with light from the second side surface 114 side (the positive side of the Y axis), and the brightness of each symbol on the display surface 111 can be improved. In addition, the symbol S2 may be omitted or a symbol may be added.

[0089] (Second Modification)

[0090] Below, refer to Figure 6 A second modification example of the display device 100 according to the embodiment will be described. Figure 6 It is a side view of a display device 100 - 3 according to a second modification.

[0091] like Figure 6 As shown, the display device 100-3 of the second variant example differs from the display device 100-2 of the first variant example in the following points: an upper extension portion 115A is provided at the upper end portion of the side reflection portion 115, which is extended toward the first side surface 113 side (the negative side of the Y axis) in a manner that covers a portion of the display surface 111, and a lower extension portion 115B is provided at the lower end portion of the side reflection portion 115, which is extended toward the first side surface 113 side (the negative side of the Y axis) in a manner that covers a portion of the bottom surface 112.

[0092] The display device 100 - 3 according to the second modification example can further reflect the light reflected by the side reflective portion 115 by the upper extension portion 115A and the lower extension portion 115B, thereby suppressing the leakage of light from the display surface 111 and the bottom surface 112 .

[0093] As mentioned above, although one embodiment of the present invention has been described, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims.

[0094] For example, the reflecting surface may be formed by forming a convex portion in a shape protruding downward on the bottom surface of the light guide instead of a concave portion in a shape recessed upward on the bottom surface of the light guide.

[0095] In addition, the reflective surface may be a structure formed by forming a concave portion in a downwardly recessed shape on the display surface (upper surface) of the light guide, or a structure formed by forming a convex portion in a shape protruding upward on the display surface (upper surface) of the light guide.

[0096] The present international application claims the priority based on Japanese Patent Application No. 2022-165543 filed on October 14, 2022, the entire contents of which are hereby incorporated by reference.

[0097] Description of Reference Numerals

[0098] 100, 100-2, 100-3 Display device

[0099] 110 Light guide

[0100] 111 Display surface

[0101] 112 Bottom

[0102] 113 First side

[0103] 114 Second side

[0104] 115 side reflector

[0105] 115A Upper extension

[0106] 115B Lower extension

[0107] 120 Light Source

[0108] 130, 130-1, 130-2, 130-3 Reflection part

[0109] 131 Reflective surface

[0110] 132 Second reflection surface

[0111] 133 recess

[0112] S1, S2, S3 symbols.

Claims

1. A display device, characterized in that: The display device comprises: Light source; and a transparent and flat light guide for receiving light emitted from the light source from a first side surface; The light guide has a reflecting portion composed of a plurality of reflecting surfaces inclined relative to a bottom surface at a plurality of positions corresponding to a plurality of symbols. The light guide body reflects the light incident from the first side surface by using the plurality of reflection surfaces through the plurality of reflection parts, thereby displaying the plurality of symbols on the display surface. The closer the reflecting portion is to the light source, the smaller the inclination angle of the reflecting surface relative to the bottom surface.

2. The display device according to claim 1, characterized in that The inclination angles of the plurality of reflection surfaces are set so that the maximum brightness is obtained when the symbol corresponding to the reflection portion farthest from the light source is visually recognized from the display surface side.

3. The display device according to claim 1, characterized in that The inclination angle of the plurality of reflection surfaces is set for each of the plurality of reflection portions so that the plurality of symbols displayed on the display surface have equal brightness.

4. The display device according to claim 1, characterized in that Among the plurality of reflection portions, projection areas of the reflection surfaces when viewed from above the display surface side are equal.

5. The display device according to claim 1, characterized in that The light guide has a side reflective portion on a second side surface opposite to the first side surface. Each of the plurality of reflection parts is integrally formed with a second reflection surface facing the side reflection part relative to the plurality of reflection surfaces. The closer the reflecting portion is to the side reflecting portion, the smaller the inclination angle of the second reflecting surface relative to the bottom surface.

6. The display device according to claim 5, characterized in that: The side reflection part has: an upper extension portion extending from an upper end portion toward the first side surface so as to cover a portion of the display surface; and A lower side extension portion extends from a lower end portion toward the first side surface so as to cover a portion of the bottom surface.

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