Indication device

Abstract

This display device comprises: a light source; and a transparent and flat plate-shaped light guide, into which light emitted from the light source enters from a first side surface of the light guide. The light guide has, at each of a plurality of positions corresponding to a plurality of symbols, a reflective part formed by a plurality of reflective surfaces inclined relative to a bottom surface. Each of the plurality of reflective parts reflects, by means of the plurality of reflective surfaces, the light that has entered from the first side surface to thereby display a plurality of symbols on a display surface. The reflective parts are configured so that the angle of inclination of the reflective surfaces is smaller relative to the bottom surface, the closer the reflective parts are to the light source.

Description

[Technical Field]

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

[0002] The following Patent Document 1 relates to a light guide plate display device that can display a pattern on the display surface of a light guide by reflecting light that is irradiated from a light source device onto the side of the light guide and enters the inside of the light guide at the reflective slope of a prism, and discloses a technology in which, in order to balance the brightness of the pattern display, the area of ​​the reflective slope of the prism farther from the light source device is made larger than the area of ​​the reflective slope of the prism closer to the light source device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-53605 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technology of Patent Document 1, the areas of the individual prisms are displayed differently among the multiple pattern displays, which may cause a user viewing the multiple pattern displays to feel uncomfortable. [Means for solving the problem]

[0005] A display device according to one embodiment includes a light source and a transparent, flat light guide into which light emitted from the light source is incident from a first side surface. The light guide has a reflective portion consisting of a plurality of reflective surfaces inclined with respect to a bottom surface at each of a plurality of positions corresponding to a plurality of symbols. Each of the plurality of reflective portions reflects the light incident from the first side surface by the plurality of reflective surfaces, thereby displaying a plurality of symbols on the display surface. The closer the reflective portion is to the light source, the smaller the inclination angle of the reflective surface with respect to the bottom surface. [Effects of the Invention]

[0006] According to one embodiment, a plurality of symbols can be displayed on the display surface of the light guide body so as to have uniform brightness without adjusting the area of ​​the reflecting portion. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a plan view of a display device according to an embodiment; [Figure 2] 1 is a side view of a display device according to an embodiment; [Figure 3A] FIG. 1 is an enlarged view of a reflective surface included in a display device according to an embodiment; [Figure 3B] FIG. 1 is an enlarged view of a reflective surface included in a display device according to an embodiment; [Figure 4A] FIG. 10 is a diagram showing the relationship between the inclination angle of the reflective surface and the brightness of the symbol in a display device according to an embodiment. [Figure 4B] FIG. 10 is a diagram showing the relationship between the inclination angle of the reflective surface and the brightness of the symbol in a display device according to an embodiment. [Figure 5] 1 is a side view of a display device according to a first modified example; [Figure 6] 10 is a side view of a display device according to a second modified example; DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment will be described below with reference to the drawings. For convenience, in the following description, the Z-axis direction in the drawings is the up-down direction, the Y-axis direction in the drawings is the left-right direction, and the X-axis direction in the drawings is the front-rear direction. However, the positive Z-axis direction is the up direction, the positive Y-axis direction is the right direction, and the positive X-axis direction is the front.

[0009] (Configuration of display device 100) Fig. 1 is a plan view of a display device 100 according to an embodiment. Fig. 2 is a side view of the display device 100 according to an embodiment. As shown in Figs. 1 and 2, the display device 100 includes a light guide 110 and a light source 120.

[0010] The light guide 110 is a transparent, flat member. The light guide 110 is made of a transparent resin material. As shown in FIG. 1, the light guide 110 has a rectangular shape with its longitudinal direction in the left-right direction (Y-axis direction) when viewed from above (positive Z-axis direction). As shown in FIG. 2, the light guide 110 is flat and has a constant thickness in the up-down direction (Z-axis direction). The light guide 110 has a display surface 111, a bottom surface 112, a first side surface 113, and a plurality of reflective portions 130.

[0011] Display surface 111 is the upper surface (horizontal surface on the positive side of the Z axis) of light guide 110. A plurality of symbols are displayed on display surface 111 when light source 120 emits light. In the example shown in FIG. 1, when light source 120 emits light, symbol S1 and symbol S2 are displayed side by side in the left-right direction (Y axis direction) on display surface 111. Symbol S1 is displayed in an area to the left of the center of display surface 111 (negative side of the Y axis). Symbol S2 is displayed in an area to the right of the center of display surface 111 (positive side of the Y axis). In FIG. 1, as an example, symbol S1 is the letter "X." Symbol S2 is the letter "Y."

[0012] The bottom surface 112 is the bottom surface (horizontal surface on the negative side of the Z axis) of the light guide 110. The bottom surface 112 is parallel to the display surface 111. The bottom surface 112 has a plurality of reflecting portions 130 provided thereon.

[0013] The first side surface 113 is the left side surface (the side surface (vertical surface) on the negative side of the Y axis) 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.

[0014] The plurality of reflecting portions 130 are provided on the bottom surface 112 of the light guide 110 at positions corresponding to the plurality of symbols. In the example shown in Fig. 2, two reflecting portions 130-1 and 130-2 are provided on the bottom surface 112 of the light guide 110, aligned in the left-right direction (Y-axis direction), corresponding to the two symbols S1 and S2 displayed on the display surface 111. The reflecting portion 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 reflecting portion 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).

[0015] Each of the reflecting portions 130-1 and 130-2 has a plurality of reflecting surfaces 131 inclined with respect to the bottom surface 112. Each of the plurality of reflecting surfaces 131 is inclined toward the first side surface 113, and is capable of reflecting light propagating through the light guide 110 from the first side surface 113 upward (positive direction of the Z axis).

[0016] The multiple reflective surfaces 131 are arranged side by side on the bottom surface 112 so that their overall shape is the same as the shape of the corresponding symbol when viewed in a plan view from above (positive direction of the Z axis). In other words, the multiple reflective surfaces 131 are arranged densely within an area surrounded by the outer shape of the symbol. As a result, the multiple reflective surfaces 131 are able to reflect reflected light whose overall shape is the same as the shape of the corresponding symbol when viewed in a plan view from above (positive direction of the Z axis) upward (positive direction of the Z axis), and therefore are visually recognized as the shape of the symbol.

[0017] For example, each of the multiple reflective surfaces 131 is formed on the bottom surface 112 of the light guide 110 by forming a recess 133 that is recessed upward (positive Z-axis direction) and has a triangular cross section when viewed from the front-to-back direction (X-axis direction).

[0018] The light source 120 is disposed on the left side (negative side of the Y axis) of the first side surface 113 of the light guide 110, facing the first side surface 113. The light source 120 is driven by a drive 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. As a result, the light source 120 causes light to enter 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.

[0019] (Display function of the display device 100) In the display device 100 configured as described above, when the light source 120 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 that enters the light guide 110 propagates within the light guide 110 while being totally reflected.

[0020] A portion of the light propagating within light guide 110 is reflected upward (in the positive direction of the Z axis) by multiple reflecting surfaces 131 provided in reflecting section 130-1, and is thereby emitted upward (in the positive direction of the Z axis) from display surface 111 of light guide 110 while maintaining the same overall shape as that of symbol S1 in a plan view from above (in the positive direction of the Z axis). As a result, symbol S1 is displayed on display surface 111 of light guide 110, and therefore symbol S1 becomes visible from above (in the positive direction of the Z axis).

[0021] Another portion of the light propagating within the light guide 110 is reflected upward (in the positive direction of the Z axis) by the multiple reflecting surfaces 131 of the reflecting section 130-2, and is thereby 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 S2 in a plan view 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, and therefore the symbol S2 becomes visible from above (in the positive direction of the Z axis).

[0022] (Inclination angle of reflecting surface 131) 3A and 3B are enlarged views of reflective surfaces 131 included in a display device 100 according to an embodiment. Fig. 3A shows one of the reflective surfaces 131 included in a reflector 130-1. Fig. 3B shows one of the reflective surfaces 131 included in a reflector 130-2.

[0023] In the display device 100 according to one embodiment, the closer the reflecting section 130 is to the light source 120, the smaller the inclination angle of the reflecting surface 131 with respect to the bottom surface 112 becomes.

[0024] 2, the reflecting portion 130-1 is closer to the light source 120 than the reflecting portion 130-2. For this reason, as shown in FIG. 3, the inclination angle θ1 of the multiple reflecting surfaces 131 of the reflecting portion 130-1 is set smaller than the inclination angle θ2 of the multiple reflecting surfaces 131 of the reflecting portion 130-2.

[0025] As a result, the direction of the reflected light with the maximum light intensity is shifted from the vertical direction, and in one embodiment of the display device 100, the component of the light intensity that is reflected by the multiple reflecting surfaces 131 toward the direction of the symbol S1 (upward and vertical) (i.e., the light that is emitted from the display surface 111 and displays the symbol S1) out of the light irradiated to the reflecting section 130-1 can be made smaller than when the direction of the reflected light with the maximum light intensity is vertical.

[0026] On the other hand, in the display device 100 according to one embodiment, the direction of the reflected light with the greatest light intensity is vertical in the reflecting section 130-2 farthest from the light source 120, and therefore, the component of the light intensity that is reflected by the multiple reflecting surfaces 131 toward the direction of the symbol S2 (upward and vertical) (i.e., the light that is emitted from the display surface 111 and displays the symbol S2) can be increased among the light irradiated to the reflecting section 130-2.

[0027] The amount of light tends to be greatest in a specific direction and to decrease when the direction deviates from the specific direction. In the reflecting section 130-2, the direction in which the amount of light is greatest is the vertical direction, but in the reflecting section 130-1, the tilt angle θ1 is set smaller than the tilt angle θ2 so that the direction in which the amount of light is greatest is shifted in the direction opposite to the light source.

[0028] Here, in the display device 100 according to one embodiment, the amount of light irradiated onto the reflecting section 130-1 closer to the light source 120 is relatively large because of its proximity to the light source 120 (the amount of attenuation is small due to the small number of total reflections), and as is, the brightness of the symbol S1 would be relatively high. However, by setting the inclination angle θ1 of the reflecting surface 131 as described above and making the amount of light reflected by the reflecting surface 131 relatively small, the brightness of the symbol S1 can be reduced to an appropriate level.

[0029] On the other hand, in the display device 100 according to one embodiment, the amount of light irradiated onto the reflecting section 130-2 farther from the light source 120 is relatively small because of its distance from the light source 120 (the amount of attenuation is large due to the large number of total reflections), and as is, the brightness of the symbol S2 becomes relatively low. However, by setting the inclination angle θ2 of the reflecting surface 131 as described above and maximizing the amount of light reflected by the reflecting surface 131, the brightness of the symbol S2 can be increased.

[0030] Therefore, the display device 100 according to the embodiment can suppress the difference in brightness between the symbol S1 and the symbol S2 displayed on the display surface 111 of the light guide 110. Therefore, the display device 100 according to the embodiment can display a plurality of symbols on the display surface 111 of the light guide 110 with uniform brightness without adjusting the area of ​​the reflective portion 130.

[0031] In this embodiment, as an example, the multiple reflective surfaces 131 provided on each of the reflective portions 130-1 and 130-2 have the same inclination angle, but this is not limited to this, and the multiple reflective surfaces 131 provided on any one of the reflective portions 130-1 and 130-2 may have different inclination angles depending on the distance from the light source 120.

[0032] (Projected area of ​​reflecting surface 131) In the display device 100 according to the embodiment, the projected areas of the individual reflecting surfaces 131 of the plurality of reflecting sections 130 are equal to each other in plan view from the display surface 111 side of the light guide 110.

[0033] 3, the reflective surface 131 of the reflecting unit 130-1 and the reflective surface 131 of the reflecting unit 130-2 have different inclination angles, but the width Y1 of the reflective surface 131 of the reflecting unit 130-1 in the left-right direction (Y-axis direction) and the width Y2 of the reflective surface 131 of the reflecting unit 130-2 in the left-right direction (Y-axis direction) are equal to each other. Note that, although not shown in the figure, the width of the reflective surface 131 of the reflecting unit 130-1 in the front-back direction (X-axis direction) and the width of the reflective surface 131 of the reflecting unit 130-2 in the front-back direction (X-axis direction) are equal to each other.

[0034] Therefore, the individual projected areas of the reflective surfaces 131 of the reflective units 130-1 and 130-2 are equal to each other in plan view from the display surface 111 side (positive side along the Z axis) of the light guide 110. Furthermore, the multiple reflective surfaces 131 of the reflective units 130-1 and the multiple reflective surfaces 131 of the reflective units 130-2 are arranged at equal intervals and with equal arrangement density in plan view from the display surface 111 side (positive side along the Z axis) of the light guide 110.

[0035] Therefore, according to the display device 100 of one embodiment, when the light source 120 is off, it is possible to suppress the apparent brightness difference caused by the projected area of ​​the reflective surface 131 of the symbol S1 and the symbol S2 displayed on the display surface 111 of the light guide 110. That is, when the light source 120 is off, the reflective surface 131 reflects external light, and the surface of the reflective surface 131 may appear whitish. If the projected area of ​​the reflective surface 131 is different in a plan view from the display surface 111 side (the positive side of the Z axis), the individual reflective surfaces 131 themselves are very small and are hardly visible to the naked eye, but when the symbols are viewed as a whole, the apparent brightness will appear different. However, according to the display device 100 of one embodiment, the projected area of ​​each reflective surface 131 is equal among the multiple symbols displayed on the display surface 111 of the light guide 110, so a user viewing the multiple symbols will not feel uncomfortable.

[0036] In this embodiment, the projected areas of the reflecting surfaces 131 of the reflecting units 130-1 and 130-2 are set equal, but instead, the actual areas of the reflecting surfaces 131 of the reflecting units 130-1 and 130-2 may be set equal. In this case, the projected areas of the reflecting surfaces 131 of the reflecting units 130-1 and 130-2 will be different, but for example, a smaller projected area can provide an effect such as allowing the reflecting surfaces 131 to be arranged more closely together.

[0037] (Example of setting the inclination angle of the reflecting surface 131) FIG. 4 is a diagram showing the relationship between the tilt angle of the reflective surface 131 and the brightness of the symbol in the positive Z-axis direction (above and vertical to the symbol) in the display device 100 according to one embodiment, and shows the results obtained by simulation.

[0038] In one embodiment of the display device 100, the inclination angle of the reflective surface 131 is set for each of the multiple reflective portions 130-1, 130-2 so that the brightness is equal among the multiple symbols displayed on the display surface 111 of the light guide 110.

[0039] Fig. 4A is a graph showing the relationship between the inclination angle of reflecting surface 131 provided in reflecting unit 130-1 and the brightness of symbol S1 displayed on display surface 111. Fig. 4B is a graph showing the relationship between the inclination angle of reflecting surface 131 provided in reflecting unit 130-2 and the brightness of symbol S2 displayed on display surface 111.

[0040] In the graph shown in FIG. 4, the inclination angle on the horizontal axis means the inclination angle of the reflecting surface 131 with respect to the bottom surface 112.

[0041] As shown in FIG. 4B, in the reflecting portion 130-2 farther from the light source 120, the inclination angle θ2 of the plurality of reflecting surfaces 131 is set to be the inclination angle D21 at which the luminance of the symbol S2 is at its maximum.

[0042] As a result, the inclination angle of the multiple reflective surfaces 131 of the reflective portion 130-2 (i.e., the reflective portion 130 farthest from the light source 120) is set so that maximum brightness is obtained when the symbol S2 corresponding to the reflective portion 130-2 is viewed from the display surface 111 side.

[0043] On the other hand, as shown in FIG. 4A, in reflecting section 130-1 closer to light source 120, inclination angle D13 at which the luminance of symbol S1 becomes equal to the luminance of symbol S2 is set as inclination angle θ1 of multiple reflecting surfaces 131.

[0044] However, as shown in Fig. 4A, on the reflecting surface 131 of the reflecting unit 130-1, there are two inclination angles at which the luminance of the symbol S1 is equal to the luminance of the symbol S2: inclination angle D11 and inclination angle D13, with inclination angle D12 at which the luminance of the symbol S1 is at its maximum value sandwiched between them. In this case, as shown in Fig. 4A, the smaller inclination angle D13 is set as the inclination angle θ1 of the multiple reflecting surfaces 131.

[0045] This is to minimize the effect of dimensional errors in the inclination angle. Specifically, as shown in FIG. 4A , the slope of the curve showing the relationship between the inclination angle of the reflecting surface 131 and the brightness of the symbol S1 is larger for inclination angle D11 than for inclination angle D13. Therefore, even if the inclination angle deviates from the reference angle due to processing or installation, the effect of inclination angle D13 on the brightness change is smaller. This is because light emitted from the light source 120 travels toward the positive side of the Y axis. Therefore, as the inclination angle of the reflecting surface increases, the angle of incidence (reflection angle) of the light with respect to the reflecting surface tends to decrease. With a small angle of incidence, the light exits the reflecting surface without being totally reflected, resulting in a significant change in brightness. On the other hand, as the angle of the reflecting surface decreases, the angle of reflection of the light with respect to the reflecting surface tends to increase, resulting in a significant change in brightness, since the totally reflected light remains in a totally reflected state.

[0046] As described above, the display device 100 according to one embodiment can easily make the luminance of the symbol S1 and the luminance of the symbol S2 displayed on the display surface 111 of the light guide 110 equal to each other.

[0047] The suitable inclination angles θ1 and θ2 of the reflecting surface 131 can be determined by a predetermined calculation formula, simulation, or the like.

[0048] (First Modification) A first modified example of the display device 100 according to an embodiment will be described below with reference to Fig. 5. Fig. 5 is a side view of a display device 100-2 according to the first modified example.

[0049] As shown in FIG. 5, a display device 100-2 according to a first modification includes, as an example of the plurality of reflectors 130, a reflector 130-1, a reflector 130-2, and a reflector 130-3 in this order from the light source 120 side (negative side of the Y axis).

[0050] The reflecting portion 130-1 displays a symbol S1 on the display surface 111 of the light guide 110. The reflecting portion 130-2 displays a symbol S2 on the display surface 111 of the light guide 110. The reflecting portion 130-3 displays a symbol S3 on the display surface 111 of the light guide 110.

[0051] Each of the reflecting portions 130-1, 130-2, and 130-3 has a plurality of reflecting surfaces 131 facing the first side surface 113 (negative side of the Y axis) on the bottom surface 112 of the light guide 110. For convenience, Fig. 5 shows one representative of the plurality of reflecting surfaces 131 provided on the reflecting portions 130-1, 130-2, and 130-3.

[0052] 5, in the display device 100-2 according to the first modification, the light guide 110 has a side reflector 115 on a second side surface 114, which is the surface opposite to the first side surface 113. The side reflector 115 is provided so as to cover the entire second side surface 114. The side reflector 115 reflects, among the light propagating inside the light guide 110, light that is irradiated onto the second side surface 114, back into the light guide 110. This allows the display device 100-2 according to the first modification to irradiate the reflectors 130-1, 130-2, and 130-3 with light also from the second side surface 114 side (the positive side of the Y axis), thereby improving the brightness of each symbol on the display surface 111. Note that the side reflector 115 may be, for example, an aluminum reflective sheet, a white reflective sheet, or white paint.

[0053] Also, as shown in Figure 5, in the display device 100-2 of the first modified example, each of the reflecting sections 130-1, 130-2, and 130-3 has a second reflecting surface 132 formed integrally with each of the multiple reflecting surfaces 131, the second reflecting surface 132 facing the side reflecting section 115 (positive side of the Y axis).

[0054] In the display device 100-2 according to the first modification, the angle of inclination of the reflecting surface 131 of the reflecting section 130 relative to the bottom surface 112 of the light guide 110 decreases as the reflecting surface 131 approaches the first side surface 113.

[0055] As a result, in the display device 100-2 of the first variant, the reflecting portion 130 closer to the first side surface 113 is closer to the light source 120 and therefore the amount of light irradiated from the first side surface 113 side (negative side of the Y axis) is greater, but the amount of light reflected by the multiple reflecting surfaces 131 toward the direction of the symbol (upward and vertically) (i.e., light emitted from the display surface 111 to display the symbol) of the light irradiated from the first side surface 113 side (negative side of the Y axis) can be made relatively small.

[0056] In the display device 100-2 according to the first modification, the angle of inclination of the second reflecting surface 132 of the reflecting portion 130 relative to the bottom surface 112 of the light guide 110 decreases as the reflecting portion 130 approaches the side reflecting portion 115.

[0057] As a result, 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) because it is closer to the side reflecting portion 115, but the amount of light reflected by the multiple second reflecting surfaces 132 toward the direction of the symbol (upward and vertically) (i.e., light emitted from the display surface 111 to display the symbol) can be relatively reduced among the light irradiated from the side reflecting portion 115 side (positive side of the Y axis).

[0058] For example, since the distance L1 from the first side surface 113 to the reflective section 130-1 is short, the amount of light irradiated from the first side surface 113 side (negative side of the Y axis) is relatively large, but since the inclination angle of the reflective surface 131 with respect to the bottom surface 112 is relatively small, the amount of light reflected by the reflective surface 131 in the direction of the symbol S1 (upward and vertically) can be relatively small, and therefore the brightness of the symbol S1 displayed on the display surface 111 can be made appropriate.

[0059] Furthermore, since the distance L3' from the side reflecting portion 115 to the reflecting portion 130-1 is long, the amount of light irradiated from the side reflecting portion 115 side (positive side of the Y axis) is relatively small, but since the inclination angle of the second reflecting surface 132 is relatively large, the amount of light reflected by the second reflecting surface 132 in the direction of the symbol S1 (upward and vertically) can be relatively large, and therefore the brightness of the symbol S1 displayed on the display surface 111 can be made appropriate.

[0060] Furthermore, for example, the reflective section 130-2 has a medium distance L2 from the first side surface 113, and therefore the amount of light irradiated from the first side surface 113 (negative side of the Y-axis) is medium, but the inclination angle of the reflective surface 131 relative to the bottom surface 112 is medium, and therefore the amount of light reflected by the reflective surface 131 in the direction of the symbol S2 (upward and vertically) can be medium, and therefore the brightness of the symbol S2 displayed on the display surface 111 can be appropriate.

[0061] Furthermore, since the distance L2' from the side reflecting portion 115 to the reflecting portion 130-2 is medium, the amount of light irradiated from the side reflecting portion 115 side (positive side of the Y axis) is relatively medium, but since the inclination angle of the second reflecting surface 132 is medium, the amount of light reflected by the second reflecting surface 132 in the direction of the symbol S2 (upward and vertical) can be made medium, and therefore the brightness of the symbol S2 displayed on the display surface 111 can be made appropriate.

[0062] Furthermore, for example, since the distance L3 from the first side surface 113 to the reflective portion 130-3 is long, the amount of light irradiated from the first side surface 113 side (negative side of the Y axis) is relatively small, but since the inclination angle of the reflective surface 131 with respect to the bottom surface 112 is relatively large, the amount of light reflected by the reflective surface 131 in the direction of the symbol S1 (upward and vertically) can be relatively large, and therefore the brightness of the symbol S3 displayed on the display surface 111 can be made appropriate.

[0063] Furthermore, since the distance L1' from the side reflecting portion 115 to the reflecting portion 130-3 is short, the amount of light irradiated from the side reflecting portion 115 side (positive side of the Y axis) is relatively large, but since the inclination angle of the second reflecting surface 132 is relatively small, the amount of light reflected by the second reflecting surface 132 in the direction of the symbol S1 (upward and vertically) can be relatively small, and therefore the brightness of the symbol S3 displayed on the display surface 111 can be made appropriate.

[0064] As described above, the display device 100 according to the first modification can easily make the luminance of the symbol S1, the luminance of the symbol S2, and the luminance of the symbol S3 displayed on the display surface 111 of the light guide 110 equal.

[0065] In addition, in the display device 100 according to the first variant, the light guide 110 has a symmetrical structure in the left-right direction (Y-axis direction) in order to make the brightness of the symbols on the display surface 111 uniform when the light source 120 is not lit.

[0066] Specifically, distance L1 from first side surface 113 of reflecting unit 130-1 is equal to distance L1' from side surface reflecting unit 115 of reflecting unit 130-3. The inclination angle of reflecting surface 131 of reflecting unit 130-1 is equal to the inclination angle of second reflecting surface 132 of reflecting unit 130-3. The inclination angle of second reflecting surface 132 of reflecting unit 130-1 is equal to the inclination angle of reflecting surface 131 of reflecting unit 130-3.

[0067] Furthermore, distance L2 from first side surface 113 of reflecting portion 130-2 is equal to distance L2' from side surface reflecting portion 115 of reflecting portion 130-2. Furthermore, the inclination angle of reflecting surface 131 of reflecting portion 130-2 is equal to the inclination angle of second reflecting surface 132 of reflecting portion 130-2.

[0068] Therefore, the width W of recesses 133 formed by adjacent reflective surfaces 131 and second reflective surfaces 132 is equal for reflective portions 130-1, 130-2, and 130-3. This allows the projection area of ​​recesses 133 onto the XY plane to be the same. Therefore, the size of recesses 133 can be made the same for all symbols, and the arrangement intervals (arrangement density) can be made constant, so that the brightness of each symbol can be made constant when light source 120 is not lit.

[0069] In the example shown in Figure 5, the reflecting surface 131 and the second reflecting surface 132 are configured to form a triangular shape (prism shape), but this is not limited to this, and the reflecting surface 131 and the second reflecting surface 132 may be configured to form other shapes (for example, a moon-cut shape, etc.).

[0070] Furthermore, in the display device 100 according to the first modification, a second light source (for example, an LED) may be provided instead of the side surface reflector 115. In this case, the display device 100-2 according to the first modification can also irradiate the reflectors 130-1, 130-2, and 130-3 with light from the second side surface 114 side (the positive side of the Y axis), thereby improving the brightness of each symbol on the display surface 111. Furthermore, the symbol S2 may be omitted, or a symbol may be added.

[0071] (Second Modification) A second modified example of the display device 100 according to the embodiment will be described below with reference to Fig. 6. Fig. 6 is a side view of a display device 100-3 according to the second modified example.

[0072] As shown in Figure 6, the display device 100-3 of the second variant differs from the display device 100-2 of the first variant in that an upper extension 115A is provided at the upper end of the side reflector 115, extending toward the first side surface 113 (negative side of the Y-axis) so as to cover part of the display surface 111, and a lower extension 115B is provided at the lower end of the side reflector 115, extending toward the first side surface 113 (negative side of the Y-axis) so as to cover part of the bottom surface 112.

[0073] The display device 100-3 of the second variant is configured so that the light reflected by the side reflecting portion 115 can be further reflected by the upper extension portion 115A and the lower extension portion 115B, thereby suppressing leakage of light from the display surface 111 and the bottom surface 112.

[0074] Although one embodiment of the present invention has been described in detail above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

[0075] For example, the reflective surface may be formed not by forming an upwardly recessed recess on the bottom surface of the light guide, but by forming a downwardly protruding convex portion on the bottom surface of the light guide.

[0076] The reflective surface may be formed by forming a concave portion that is recessed downward on the display surface (upper surface) of the light guide, or by forming a convex portion that protrudes upward on the display surface (upper surface) of the light guide.

[0077] This international application claims priority to Japanese Patent Application No. 2022-165543, filed on October 14, 2022, the entire contents of which are incorporated herein by reference. [Explanation of symbols]

[0078] 100,100-2,100-3 Display device 110 Light guide 111 Display surface 112 bottom 113 First Aspect 114 The Second Aspect 115 Side reflector 115A Upper extension 115B Lower extension 120 light source 130,130-1,130-2,130-3 Reflector 131 Reflective surface 132 Second reflective surface 133 Recess S1,S2,S3 symbols

Claims

1. A light source and a transparent, flat light guide into which light emitted from the light source is incident from a first side surface; Equipped with The light guide is a reflecting portion having a plurality of reflecting surfaces inclined with respect to a bottom surface at each of a plurality of positions corresponding to a plurality of symbols; each of the plurality of reflecting portions reflects the light incident from the first side surface by the plurality of reflecting surfaces, thereby displaying the plurality of symbols on a display surface; the reflecting portion is closer to the light source, the smaller the inclination angle of the reflecting surface with respect to the bottom surface, The reflecting portion farthest from the light source is The inclination angles of the plurality of reflective surfaces are set so that maximum brightness can be obtained when the symbol corresponding to the reflective portion is viewed from the display surface side. A display device characterized by:

2. The inclination angles of the plurality of reflective surfaces are set for each of the plurality of reflective portions so that the luminance of the plurality of symbols displayed on the display surface is equal.

2. The display device according to claim 1.

3. The projected areas of the individual reflecting surfaces of the plurality of reflecting sections are equal in plan view from the display surface side.

2. The display device according to claim 1.

4. The light guide is a side surface reflecting portion on a second side surface opposite to the first side surface; Each of the plurality of reflecting portions is a second reflecting surface facing the side reflecting portion is integrally formed with each of the plurality of reflecting surfaces, The reflecting portion is The closer to the side reflecting portion, the smaller the inclination angle of the second reflecting surface with respect to the bottom surface.

2. The display device according to claim 1.

5. The side surface reflecting portion is 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; a lower extension portion extending from a lower end portion toward the first side surface so as to cover a portion of the bottom surface; 5. The display device according to claim 4, further comprising:

Images