Light guide member, lighting device, and display device

Abstract

The present invention provides a light guide member, a lighting device, and a display device, which emit parallel light traveling in a direction perpendicular to an emission surface having a curved surface. The light guide member (120) on one side of the present invention has: an incident surface (123) on which light from a light source (22) is incident, at least one reflection surface (121) that reflects the light incident on the incident surface (123), and an emission surface (122) formed by a curved surface and that emits the light reflected by the reflection surface (121). The reflection surface (121) reflects the light incident from the light source (22) in a direction in which the incident angle with respect to the incident emission surface (122) is constant.

Description

Technical Field

[0001] The present invention relates to a light guide member that guides incident light and emits it as parallel light, and an illumination device and a display device having the light guide member. Background Art

[0002] In Patent Document 1, a light guide member for emitting parallel light and an illumination device having the light guide member are disclosed. The light guide member has: an incident surface on which light from a light source is incident, a first reflection surface that totally reflects the light incident from the incident surface, a second reflection surface that totally reflects the light totally reflected by the first reflection surface as parallel light, and an emission surface that emits the parallel light totally reflected by the second reflection surface.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Laid-Open Gazette "(Japan) Tokkai 2018-055986" (published on April 5, 2018) Summary of the Invention

[0006] Technical Problem to be Solved by the Invention

[0007] However, in the case where the emission surface of the light guide member disclosed in Patent Document 1 is a curved surface, there is a problem that the incident angle of the light emitted from the emission surface to the emission surface is not constant and the light cannot be emitted as parallel light.

[0008] An object of one aspect of the present invention is to realize a light guide member capable of emitting light with a constant incident angle with respect to an emission surface having a curved surface.

[0009] Technical Solution for Solving the Technical Problem

[0010] To solve the above problems, a light guide member according to one aspect of the present invention has: an incident surface on which light from a light source is incident, at least one reflection surface that reflects the light incident from the incident surface, and an emission surface formed by a curved surface that emits the light reflected by the reflection surface, and the reflection surface reflects the light incident from the light source in a direction in which the incident angle to the emission surface is constant.

[0011] Effects of the Invention

[0012] According to one aspect of the present invention, it is possible to realize a light guide member capable of emitting light with a constant incident angle with respect to an emission surface having a curved surface. Brief Description of the Drawings

[0013] Figure 1 An example of the application scenario of the display device according to the first embodiment is shown.

[0014] Figure 2 It is a view when observing the light guide plate of the display device from the perspective of an observer.

[0015] Figure 3 It is a view for explaining the connection part of the display device according to the first embodiment.

[0016] Figure 4 It is a perspective view of the display device according to the first embodiment.

[0017] Figure 5 It is a top view of the lighting device included in the display device.

[0018] Figure 6 It is a view showing the traveling route of the light emitted from the lighting device of the light guide plate.

[0019] Figure 7 It is a perspective view showing a modified example of the display device.

[0020] Figure 8 It is a top view of the lighting device included in the modified example of the display device.

[0021] Figure 9 It is a perspective view of a modified example of the display device.

[0022] Figure 10 It is a perspective view of a modified example of the display device and a top view of the lighting device.

[0023] Figure 11 It is a perspective view of a modified example of the display device and a top view of the lighting device.

[0024] Figure 12 It is a perspective view showing a modified example of the display device.

[0025] Figure 13 It is a top view of the lighting device included in the modified example of the display device.

[0026] Figure 14 It is a top view showing a modified example of the light guide member.

[0027] Figure 15 It is a perspective view of the light guide plate.

[0028] Figure 16 It is a cross-sectional view showing the structure of the light guide plate.

[0029] Figure 17 It is a top view showing the structure of the light guide plate.

[0030] Figure 18 It is a perspective view showing the structure of the light path changing portion provided in the light guide plate.

[0031] Figure 19 It is a perspective view showing the arrangement of the optical path changing section.

[0032] Figure 20 It is a perspective view showing a method of forming a stereoscopic image by a light guide plate. Detailed Embodiment

[0033] Hereinafter, an embodiment of one aspect of the present invention (hereinafter also referred to as "this embodiment") will be described based on the accompanying drawings. However, the embodiment described below is merely an illustration of the present invention in all aspects. Various improvements and modifications can be made without departing from the scope of the present invention. That is, in the implementation process of the present invention, specific structures corresponding to the embodiment can also be appropriately adopted.

[0034] §1 Application Example

[0035] First, using Figures 1 to 5 , an example of the scenario to which the present invention is applicable will be described. Figure 1 An example of the applicable scenario of the display device 1 showing one embodiment of the present invention. Figure 2 It is a view of the light guide plate 11 included in the display device 1 as viewed from the perspective of an observer located outside the vehicle C. Figure 3 It is a view for explaining the connecting portion 33 of the display device 1 according to the first embodiment. Figure 4 It is a perspective view of the display device 1. Figure 5 It is a top view of the lighting device 12 included in the display device 1. The display device 1 is a device for displaying a stereoscopic image inside the light guide plate 11 or in a space outside the light guide plate 11. In this case, as Figure 4 shown, the display device 1 includes a light guide plate 11 and a lighting device 12. As Figure 1 shown, the display device 1 of this embodiment can be applied to the taillight 1A of the vehicle C.

[0036] As Figure 2 shown, the light exit surface 11B of the light guide plate 11 is formed as a curved surface. The light guide plate 11 is a component that displays the stereoscopic image I by changing the optical path of the parallel light (refer to Figure 5 ) incident from the incident surface 11A by using the optical path changing section group (optical path changing section) 113 formed inside the light guide plate 11. As Figure 3 and Figure 4 shown, the lighting device 12 includes a light source 22 and a light guide member 120. The lighting device 12 is a device for providing the parallel light required for imaging the stereoscopic image I with respect to the light guide plate 11. The light guide member 120 is a component for converting the diffused light from the light source 22 into parallel light by making the incident angle of the incident exit surface 122 constant.

[0037] The light guide member 120 of the present embodiment can convert the light from the light source 22 into parallel light traveling in a direction with a constant incident angle on the emission surface 122 formed by the curved surface. For example, the light guide member 120 can convert the light from the light source 22 into parallel light traveling in a direction perpendicular to the emission surface 122 formed by the curved surface. The lighting device 12 having the light guide member 120 can provide the parallel light required for imaging the stereoscopic image I with respect to the light guide plate 11 having a curved surface. Therefore, the display device 1 can image the stereoscopic image as expected. The specific structures of the light guide plate 11 and the lighting device 12 will be described in detail below.

[0038] §2 Structural Example

[0039] [First Embodiment]

[0040] (Structure of Display Device 1)

[0041] Using Figures 2 to 5 , the exemplary display device 1 and lighting device 12 of the present embodiment will be described. Figure 4 is a perspective view of the display device 1 of the present embodiment. As Figure 4 shown, the display device 1 includes: a lighting device 12, a connecting portion 33, and a light guide plate 11. The display device 1 is arranged such that the convex surface of the light guide plate 11 forms a part of the outer surface of the vehicle C. That is, the lighting device 12 is housed inside the vehicle C.

[0042] The lighting device 12 is a device for emitting light (hereinafter also referred to as parallel light) parallel to the direction perpendicular to the incident surface 11A (see Figure 2 ) of the light guide plate 11 described later to the light guide plate 11. The detailed structure of the lighting device 12 will be described later.

[0043] The connecting portion 33 is a part connecting the lighting device 12 and the light guide plate 11, and is formed of a transparent resin material such as polycarbonate resin and polymethyl methacrylate resin. Using the connecting portion 33, the lighting device 12 and the light guide plate 11 are connected so that the traveling direction of the light emitted from the lighting device 12 is substantially perpendicular to the traveling direction of the light in the light guide plate 11.

[0044] The connecting portion 33 has a curvature with respect to the traveling direction of the light emitted from the lighting device 12, and can change the traveling direction. Figure 3 is a diagram for explaining the connecting portion 33 of the display device 1. In Figure 3 , R is the radius of curvature of the connecting portion 33, and T is the thickness of the light guide plate 11. In Figure 3 , the difference in the degree of light leakage caused by the difference in the value of R divided by T is shown. The arrow E indicates the traveling direction of the light emitted from the lighting device 12.Figure 3 The blackened positions in the respective figures indicate the light leaking from the connecting portion 33. As Figure 3 shown, the greater the curvature of the connecting portion 33 (the smaller the radius of curvature R), the greater the light leakage from the connecting portion 33. When the value of R / T is 3 or more, the light leakage from the connecting portion 33 is sufficiently reduced. When the value of R / T is 5 or more, light does not leak from the connecting portion 33.

[0045] The light guide plate 11 is a component that deflects the parallel light emitted from the lighting device 12 and incident on the inside of the light guide plate 11 inside the light guide plate 11 and emits it from the light emitting surface 11B of the light guide plate 11. As a material for forming the light guide plate 11, for example, polycarbonate resin, polymethyl methacrylate resin, etc. can be used. As Figure 2 shown, a plurality of optical path changing portion groups 113 are formed on the back surface 11D of the light guide plate. The optical path changing portion groups 113 are continuously formed along a line where a plane parallel to the incident surface 11A intersects the back surface 11D. Each optical path changing portion included in the optical path changing portion groups 113 is formed by a part of a Fresnel lens, and the focusing points of the respective optical path changing portions are different from each other. Thus, as Figure 2 shown, a virtual image of the stereoscopic image I is formed by the set of the focusing points of the respective optical path changing portions. That is, in the display device 1, light is incident on the light guide plate 11 from the lighting device 12, and the optical path is deflected and emitted by using the optical path changing portion groups 113 formed on the light guide plate 11, whereby the stereoscopic image I can be imaged. As a result, information can be provided to an observer outside the vehicle C, and it can be used as a taillight and a brake light of the vehicle C.

[0046] In addition, the display device 1 forms the stereoscopic image I in a space closer to the inside of the vehicle C than the light guide plate 11. Thereby, the brake light and the taillight can have a sense of depth.

[0047] (Structure of the lighting device 12)

[0048] Figure 5 is a top view of the lighting device 12 included in the display device 1. As Figure 5 shown, the lighting device 12 includes a light source 22 (in the following description, in order to distinguish the light source 22, it is sometimes referred to as the light source 22A and the light source 22B), and a light guide member 120.

[0049] The light source 22 is a light source that emits light to the light guide member 120. The light source 22 is, for example, an LED (Light Emitting Diode) light source. The light source 22 can be a monochromatic LED light source, or a combination of three LED light sources that emit red, green, and blue light. When the light source 22 has a three-color LED light source, by adjusting the intensity of the light emitted from each LED light source, various colors of light can be emitted. Thereby, the color of the stereoscopic image I can be changed according to the use.

[0050] The light guide member 120 is a member for converting diffused light incident from the light source 22 into parallel light and emitting it. The light guide member 120 has: an incident surface 123 (123A and 123B), a reflection surface 121 (121A and 121B), and an emission surface 122. As the material for forming the light guide member 120, for example, a transparent resin material such as polycarbonate resin or polymethyl methacrylate resin can be used.

[0051] The incident surfaces 123A and 123B are surfaces on which light from the respective light sources 22A and 22B is incident.

[0052] The reflection surfaces 121A and 121B are surfaces for reflecting the light incident from the respective incident surfaces 123A and 123B in a direction perpendicular to the emission surface 122. The reflection surface 121 has a planar structure and can be used as a total reflection surface. In this case, at least a part of the light incident from the incident surface 123 is reflected by total reflection. That is, the reflection surface 121 can suppress the divergence of the light incident from the incident surface 123 and can make the angle of the light incident on the emission surface constant. The amount of light reflected by total reflection depends on the absolute refractive index of the light guide member 120 and the angle at which the light is incident on the reflection surface 121. When the amount of light reflected by total reflection is small, a reflection layer can also be formed on the reflection surface 121 by metal evaporation or the like. The formation of this reflection layer is not limited to metal evaporation, and can also be formed by methods such as sputtering or painting.

[0053] The emission surface 122 is a surface for emitting the light reflected by the reflection surface 121. Hereinafter, the direction parallel to the incident surface 123, the reflection surface 121, and the emission surface 122 ( Figure 5 the direction perpendicular to the paper surface in the figure) will be described as the thickness direction. In the present embodiment, in a cross section perpendicular to the thickness direction, when the light incident on the emission surface 122 extends in the direction of the reflection surface 121, a part of an arc centered on the point where the light intersects is formed. The direction perpendicular to the emission surface mentioned above is, in other words, the direction perpendicular to the tangent of the arc (the normal direction).

[0054] (The traveling route of light)

[0055] Next, with reference to Figure 5 and Figure 6 , the traveling route of the light emitted from the light source 22 will be described.

[0056] In Figure 5In the figure, the dashed line indicates the traveling route of light in the lighting device 12. The light emitted from the light source 22A is generally diffused light, which enters the light guide member 120 from the incident surface 123A and reaches the reflection surface 121A. The light reaching the reflection surface 121A is reflected by the reflection surface 121A. Here, the light source 22A is arranged such that in the cross-section perpendicular to the thickness direction, the point symmetric to the reflection surface 121A coincides with the center point of the above-mentioned circular arc. Thus, the light reflected by the reflection surface 121A travels in the direction perpendicular to the exit surface 122 in the cross-section perpendicular to the thickness direction and exits from the exit surface 122. That is, the light emitted from the light source 22 passes through the lighting device 12, is converted into parallel light, and exits. The same applies to the light emitted from the light source 22B.

[0057] Figure 6 FIG. is a diagram showing the traveling route of the light emitted from the lighting device 12 in the light guide plate 11, and is a view of the light guide plate 11 observed from the direction of the arrow shown in Figure 5 In the figure, the dashed line indicates the traveling route of the light. The light emitted from the exit surface 122 enters the light guide plate 11 via the connecting portion 33 as parallel light in the direction perpendicular to the incident surface 11A of the light guide plate 11 and travels within the light guide plate 11. Figure 6 In the figure, the dashed line indicates the traveling route of the light. The light emitted from the exit surface 122 enters the light guide plate 11 via the connecting portion 33 as parallel light in the direction perpendicular to the incident surface 11A of the light guide plate 11 and travels within the light guide plate 11.

[0058] (Effect of the First Embodiment)

[0059] As described above, the light guide member 120 of the present embodiment has: (1) an incident surface 123 on which the light from the light source 22 is incident, (2) a reflection surface 121 that reflects the light incident from the incident surface 123, and (3) an exit surface 122 formed by a curved surface that emits the light reflected by the reflection surface 121. The reflection surface 121 reflects the light incident from the light source 22 in the direction perpendicular to the exit surface 122.

[0060] According to the above structure, the light from the light source 22 becomes the light reflected by the reflection surface 121 and traveling in the direction perpendicular to the exit surface 122 having a curved surface. That is, by using the light guide member 120, the light from the light source 22 can be converted into parallel light.

[0061] In addition, in the light guide member 120 of the present embodiment, the reflection surface 121 reflects the light incident from the light source 22 in the direction perpendicular to the exit surface 122. According to the above structure, the light guide member 120 can convert the light from the light source 22 into parallel light.

[0062] In addition, in the light guide member 120 of the present embodiment, when the direction parallel to the incident surface 123, the reflection surface 121, and the exit surface 122 is defined as the thickness direction, the cross-sectional shape of the curved surface perpendicular to the thickness direction is formed as an arc. In addition, the cross-sectional shape of the reflection surface 121 perpendicular to the thickness direction is a plane in which the point that is point-symmetrical to the light source 22 with respect to the reflection surface 121 coincides with the center point of the arc. According to the above structure, since the reflection surface 121 is a plane, the light guide member 120 can be easily manufactured.

[0063] In addition, the light guide member 120 of the present embodiment includes: (1) an incident surface 123A and an incident surface 123B, and (2) reflection surfaces 121A and 121B corresponding to the incident surface 123A and the incident surface 123B, respectively. The light reflected by the reflection surfaces 121A and 121B exits from different regions of each of the exit surfaces 122.

[0064] According to the above structure, the incident surface 123A and the incident surface 123B can be arranged close to the light guide plate 11. Compared with the case where the light source is arranged to provide light perpendicular to the exit surface 122 of the light guide member 120 (for example, the case where the light source is arranged at the center point of the above arc), the depth of the light guide member 120 (the depth when viewed from the Figure 3 arrow direction) can be shortened.

[0065] In addition, the lighting device 12 of the present embodiment includes a light guide member 120 and a light source 22. According to the above structure, the lighting device 12 can provide collimated parallel light in a direction perpendicular to the incident surface 11A of the light guide plate 11.

[0066] In addition, the display device 1 of the present embodiment includes: a lighting device 12, and a light guide plate 11 that guides the light incident from the lighting device 12, reflects it by an optical path changing unit group 113 formed at a specified position, and exits from a light exit surface 11B.

[0067] According to the above structure, in the display device 1, the light guide plate 11 forms an image in the space outside the light guide plate 11 by using the light exiting from the light exit surface 11B. Thus, the display device 1 can form a stereoscopic image I as expected (in other words, can form a clear stereoscopic image I). However, in the display device 1, the light guide plate 11 can also display a planar image inside the light guide plate 11 by using the light exiting from the light exit surface 11B. In this case, the display device 1 can display a planar image.

[0068] That is, the display device 1 configured as described above is easy to manufacture, and can provide a stereoscopic image I or a planar image to an observer in a simple and miniaturized shape.

[0069] It should be noted that in one aspect of the present invention, the structure including the light guide member 130 and the connecting portion 33 may also be regarded as the light guide member. In this case, the light guide member includes: the light guide member 130, and the connecting portion 33 as the emission direction changing portion that changes the traveling direction of the light emitted from the emission surface 122 to a direction parallel to the above-mentioned thickness direction. In this case, the emission surface of the light guide member is the surface that abuts against the light guide plate 11 of the connecting portion 33. With the light guide member having the above structure, parallel light can be emitted in a direction parallel to the thickness direction.

[0070] In the present embodiment, the case where the display device 1 is applied as the tail lamp 1A of the vehicle C is illustrated, but it is not limited to this use. The display device 1 can also be applied to, for example, game machines, in-vehicle display devices, air switches, etc.

[0071] Specifically, as an application example of a game machine, for example, it can also be at least one of the multiple switches of an operation panel operated by a user, and the light guide plate 11 forms a stereoscopic image I. As an application example of an in-vehicle display device, for example, it can also be applied to a device for displaying a speedometer, etc., and the light guide plate 11 forms a stereoscopic image I. As an application example of an air switch, for example, it can also be applied to the input portion of an elevator, and the light guide plate 11 forms a stereoscopic image I.

[0072] §3 Variation

[0073] Above, the embodiments of the present invention have been described in detail, but the above description is only illustrative of the present invention in all aspects. Various improvements and deformations can be made without departing from the scope of the present invention. For example, the following changes can be made. It should be noted that hereinafter, for the main components having the same structure as those in the above embodiment, the same reference numerals are used, and the description of the same aspects as those in the above embodiment is appropriately omitted. The following variation examples can be combined as appropriate.

[0074] <3.1>

[0075] Using Figures 7 to 9 , the display device 2 as a variation of the display device 1 will be described. Figure 7 is a perspective view showing the display device 2. As Figure 7 shown, the display device 2 includes: a lighting device 13, a connecting portion 33, and a light guide plate 11.

[0076] Figure 8 is a top view of the lighting device 13 included in the display device 2. As Figure 8As shown, the lighting device 13 includes a light source 22 (light sources 22A and 22B) and a light guide member 130. The light guide member 130 has an incident surface 133 (incident surfaces 133A and 133B), a reflection surface 131 (reflection surfaces 131A and 131B), and an exit surface 132.

[0077] As Figure 8 shown, the difference between the light guide member 130 and the light guide member 120 is that the reflection surface 131 (131A and 131B) has a curved surface structure. In addition, a part of a circular arc is formed on the exit surface 132 of the lighting device 13. It should be noted that in the lighting device of this modified example, in a cross-section perpendicular to the thickness direction, the exit surface of the lighting device may also be a curved surface other than a circular arc.

[0078] The reflection surfaces 131A and 131B are curved surfaces that are recessed with respect to the exit surface 132. The reflection surface 131 can be used as a total reflection surface. In this case, at least a part of the light incident from the incident surface 133 is reflected by total reflection. The amount of light reflected by total reflection depends on the absolute refractive index of the light guide member 130 and the angle at which the light is incident on the reflection surface 121. When the amount of light reflected by total reflection is small, metal evaporation can also be performed on the reflection surface 121. The reflection surfaces 131A and 131B are formed by a plurality of surfaces that reflect the light incident from the incident surface 133 at different angles, and can be formed by a Fresnel lens, for example. As Figure 8 shown by the dashed line, the diffused light emitted from the light sources 22A and 22B enters the light guide member 130 from the incident surfaces 133A and 133B and reaches the reflection surfaces 131A and 131B. The light reaching the reflection surfaces 131A and 131B is reflected by the above-mentioned plurality of surfaces, reflected in a direction perpendicular to the exit surface 132, and exits from the exit surface 132. That is, the light emitted by the light source 22 is converted into parallel light by the light guide member 130 and exits.

[0079] Figure 9 is a perspective view of the display device 2. In Figure 9 it, the traveling routes of the light emitted from the light sources 22A and 22B in the display device 2 are indicated by dashed lines. As Figure 9 shown, the light exiting perpendicularly to the exit surface 132 of the light guide member 130 enters the light guide plate 11 via the connecting portion 33 as parallel light in a direction perpendicular to the incident surface (not shown) of the light guide plate 11.

[0080] According to the above structure, the lighting device 13 can provide collimated parallel light with respect to the light guide plate 11.

[0081] The reflecting surface 131 of the light guide member 130 has a curve in a cross section perpendicular to the thickness direction, and can provide continuous light without dark lines with respect to the light emitting surface 132. In addition, the lighting device 13 can shorten the depth for the same reason as the lighting device 12 of the first embodiment by having the reflecting surface 131.

[0082] <3.2>

[0083] Figure 10 The reference numeral 901 is a perspective view of a display device 3 which is a modified example of the display device 1 of the first embodiment. As Figure 10 shown, the display device 3 includes: a lighting device 14, a connecting portion 33, and a light guide plate 11.

[0084] Figure 10 The reference numeral 902 is a top view of the lighting device 14 included in the display device 3. As Figure 10 shown, the lighting device 14 includes two light sources 22 (light source 22A and light source 22B), and a light guide member 140. The light guide member 140 has: an incident surface 143 (143A and 143B), a reflecting surface 141 (141A and 141B), and a light emitting surface 142.

[0085] As Figure 10 shown, the difference between the light guide member 140 and the light guide member 120 is that the shape of the reflecting surface formed by the two reflecting surfaces 141A and 141B is recessed with respect to the light emitting surface 142. In addition, light restricting portions 144A and 144B are respectively formed between the incident surfaces 143A and 143B and the light guide member 140.

[0086] The light restricting portions 144A and 144B are shaped such that the ends of the light guide member 140 are elongated, and have the effect of restricting the light guiding angle of the light incident from the incident surface 143. Specifically, the light restricting portions 144A and 144B respectively restrict the range of the light emitted from the light sources 22A and 22B so that the light emitted from the light sources 22A and 22B is irradiated only onto the corresponding reflecting surfaces 141. By having the light restricting portions 144 configured in this way, it is possible to prevent the light sources 22A and 22B from irradiating reflecting surfaces other than the corresponding reflecting surfaces 141. Thereby, it is possible to prevent the generation of stray light.

[0087] The reflecting surfaces 141A and 141B are respectively planar structures and can be used as total reflection surfaces. In this case, at least a part of the light incident from the incident surface 143 is reflected by total reflection. The amount of light reflected by total reflection depends on the absolute refractive index of the light guide member 140 and the angle at which the light is incident on the reflecting surface 141. In the case where the amount of light reflected by total reflection is small, metal evaporation may be performed on the reflecting surface 121. As Figure 10As shown by the dashed lines, the diffused light emitted from the light sources 22A and 22B enters the light guide member 140 from the incident surfaces 143A and 143B, and reaches the reflection surfaces 141A and 141B. The light reaching the reflection surfaces 141A and 141B is reflected in a direction perpendicular to the emission surface 142, and is emitted from the emission surface 142. That is, the light emitted from the light source 22 is converted into parallel light by the light guide member 140 and emitted.

[0088] As described above, the light guide member 140 of the present embodiment has the light restricting portions 144A and 144B that restrict the range of the light incident from the incident surfaces 143A and 143B, so that the light incident from the incident surfaces 143A and 143B is irradiated only to the corresponding reflection surfaces 141A and 141B.

[0089] According to the above structure, the light guide member 140 can prevent the generation of stray light by having the light restricting portion 144. In addition, according to the above structure, by reflecting the light from the light source 22 once by the reflection surface 121, the light travels in a direction perpendicular to the emission surface 122 having a curved surface, and can be converted into parallel light.

[0090] <3.3>

[0091] Figure 11 The reference numeral 1001 indicates a perspective view of a display device 4 as a modified example of the display device 1. As Figure 11 shown, the display device 4 includes: an illumination device 15, a connection portion 33, and a light guide plate 11.

[0092] Figure 11 The reference numeral 1002 is a top view of the illumination device 15 included in the display device 4. As Figure 11 shown, the illumination device 15 includes a light source 22 and a light guide member 150. The light guide member 150 has: an incident surface 153, a reflection surface 151, and an emission surface 152.

[0093] As Figure 11As shown, the light guide member 150 differs from the light guide member 120 in that the light source 22 is one and the shape of the reflecting surface 151. The reflecting surface 151 is formed by a curved surface that protrudes with respect to the incident direction of light from the light source 22. The shape of this curved surface is such that the light incident from the light source 22 is reflected in a direction perpendicular to the exit surface 152. In addition, the farther the position where the light reflected by the reflecting surface 151 is reflected on the reflecting surface 151 is from the light source 22, the shorter the distance for this light to reach the exit surface 152. Further, the reflecting surface 151 is formed such that a straight line connecting any point on the reflecting surface 151 and the light source 22 intersects the reflecting surface 151 only at the above-mentioned arbitrary point. Specifically, the end portion of the reflecting surface 151 facing the light source 22 is designed to shorten the distance between the reflecting surface 151 and the exit surface 152. Thus, since all the light emitted from the light source 22 can be irradiated onto the reflecting surface 151, light can be emitted in all regions of the exit surface 152 in a cross-section perpendicular to the thickness direction.

[0094] The reflecting surface 151 can be used as a total reflection surface. In this case, at least a part of the light incident from the incident surface 153 is reflected by total reflection. The amount of light reflected by total reflection depends on the absolute refractive index of the light guide member 150 and the angle at which the light is incident on the reflecting surface 151. In the case where the amount of light reflected by total reflection is small, metal evaporation can also be performed on the reflecting surface 151.

[0095] As Figure 11 shown by the dashed line in the reference numeral 1002, the diffused light emitted from the light source 22 enters the light guide member 150 from the incident surface 153 and reaches the reflecting surface 151. The light reaching the reflecting surface 151 is reflected in a direction perpendicular to the exit surface 152 and exits from the exit surface 152. That is, the light emitted by the light source 22 is converted into parallel light by the light guide member 160 and exits.

[0096] As described above, the light guide member 150 of the present embodiment has only one incident surface 153.

[0097] According to the above structure, interference between the light guide member 150 and other light sources can be avoided. The lighting device 15 can provide parallel light that is collimated with respect to the light guide plate 11. In addition, since the lighting device 15 has the reflecting surface 151, the depth can be shortened for the same reason as the lighting device 12 of the first embodiment.

[0098] <3.4>

[0099] Figure 12 is a perspective view showing a display device 5 as a modified example of the display device 1. As Figure 12 shown, the display device 5 includes: a lighting device 16, a connecting portion 33, and a light guide plate 11.

[0100] Figure 13 is a top view of the lighting device 15 included in the display device 5. Figure 13 The reference numeral 1201 indicates an overall view of the lighting device 16, and the reference numeral 1202 is an enlarged view of the portion surrounded by the frame P in the reference numeral 1201. As Figure 13 shown, the lighting device 16 includes a light source 22 and a light guide member 160. The light guide member 160 has an incident surface 163, a first reflection surface 161A, a second reflection surface 161B, and an exit surface 162.

[0101] As Figure 13 shown, the difference between the light guide member 150 and the light guide member 120 is that the light guide member unit having one incident surface ( Figure 13 the portion shown by the reference numeral 1202) has a continuous shape. In addition, the difference between the above-described light guide member unit and the light guide member 120 is that each has a first reflection surface 161A and a second reflection surface 161B.

[0102] The first reflection surface 161A is a surface for reflecting the light incident from the incident surface 163 toward the second reflection surface 161B. The second reflection surface 161B is a surface for reflecting the light reflected by the first reflection surface 161A in a direction perpendicular to the exit surface 162.

[0103] The first reflection surface 161A can be used as a total reflection surface. In this case, at least a part of the light incident from the incident surface 163 is reflected by total reflection. The second reflection surface 161B is formed by a curved surface that is recessed with respect to the incident direction of the light reflected by the first reflection surface 161A. The shape of this curved surface is formed such that the light reflected by the first reflection surface 161A is reflected in a direction perpendicular to the exit surface in a cross section perpendicular to the thickness direction. The second reflection surface 161B can be used as a total reflection surface. In this case, at least a part of the light reflected by the first reflection surface 161A is reflected by total reflection. In the first reflection surface 161A and the second reflection surface 161B, the amount of light reflected by total reflection depends on the absolute refractive index of the light guide member 160 and the angles at which the light is incident on the first reflection surface 161A and the second reflection surface 161B. When the amount of light reflected by total reflection is small, metal evaporation can also be performed on the first reflection surface 161A and / or the second reflection surface 161B.

[0104] As Figure 13As shown by the dashed line in the marker 1202, the diffused light emitted from the light source 22 enters the light guide member 150 from the incident surface 163, reaches the first reflection surface 161A, and is reflected in the direction of the second reflection surface 161B. The light reflected by the first reflection surface 161A is reflected by the second reflection surface 161B in a direction perpendicular to the exit surface 162 and exits from the exit surface 162. That is, the light emitted from the light source 22 is converted into parallel light by the light guide member 160 and exits.

[0105] According to the above structure, the lighting device 15 can provide parallel light that is collimated with respect to the light guide plate 11.

[0106] <3.5>

[0107] Figure 14 is a top view of the lighting device 17 showing a modified example of the light guide member 120. As Figure 14 shown, the lighting device 17 has a light guide member 170 instead of the above light guide member 160. The light guide member 170 has: an incident surface 173, a reflection surface 171, and an exit surface 172.

[0108] As Figure 14 shown, the difference between the light guide member 170 and the light guide member 120 is that the light guide member unit having one incident surface 173 has a continuous shape. In addition, the difference between the above light guide member unit and the light guide member 160 is that the light is reflected in a direction perpendicular to the exit surface 172 by one reflection by each reflection surface 171.

[0109] The reflection surface 171 is formed by a curved surface that is concave with respect to the incident direction of the light emitted from the light source 22 and incident from the incident surface 173. The shape of this curved surface is such that the light reflected by the reflection surface 171 is reflected in a direction perpendicular to the exit surface 172. The reflection surface 171 can be used as a total reflection surface. In this case, at least a part of the light reflected by the reflection surface 171 is reflected by total reflection. The amount of light reflected by total reflection depends on the absolute refractive index of the light guide member 170 and the angle at which the light is incident on the reflection surface 171. In the case where the amount of light reflected by total reflection is small, metal evaporation can also be applied to the reflection surface 171.

[0110] As Figure 14 shown by the dashed line, the diffused light incident on the light guide member 170 from the incident surface 173 is reflected by the reflection surface 171 in a direction perpendicular to the exit surface 172 and exits from the exit surface 172.

[0111] According to the above structure, the light emitted from the light source 22 is converted into parallel light by the light guide member 170 and exits.

[0112] <3.6>

[0113] Refer to Figures 15 to 20 , and a light guide plate 110, which is a modified example of the display device 1, will be described.

[0114] Figure 15 is a perspective view of the light guide plate 110. Figure 16 is a cross-sectional view showing the structure of the light guide plate 110. Figure 17 is a top view showing the structure of the light guide plate 110. Figure 18 is a perspective view showing the structure of the optical path changing portion 116 provided in the light guide plate 110.

[0115] The light guide plate 110 is a component that guides the light (incident light) incident from an illumination device (not shown). The light guide plate 110 is formed of a transparent resin material having a relatively high refractive index. As the material for forming the light guide plate 110, for example, polycarbonate resin, polymethyl methacrylate resin, etc. can be used. In this modified example, the light guide plate 110 is formed of polymethyl methacrylate resin. As Figure 15 shown, the light guide plate 110 has: an emission surface 115a (light emission surface), a back surface 115b, and an incident surface 115c.

[0116] The emission surface 115a is a surface that guides the light inside the light guide plate 110 and emits the light whose optical path has been changed by the optical path changing portion 116 described later. The emission surface 115a constitutes the front surface of the light guide plate 110. The back surface 115b is a surface parallel to the emission surface 115a and is the surface on which the optical path changing portion 116 described later is disposed. The incident surface 115c is a surface that incident the light emitted from an illumination device (not shown) into the inside of the light guide plate 110.

[0117] The light incident on the light guide plate 110 from the incident surface 115c is totally reflected by the emission surface 115a or the back surface 115b and is guided inside the light guide plate 110.

[0118] As Figure 16 shown, the optical path changing portion 116 is formed on the back surface 115b inside the light guide plate 110 and is a component for changing the optical path of the light guided inside the light guide plate 110 and emitting it from the emission surface 115a. A plurality of optical path changing portions 116 are provided on the back surface 115b of the light guide plate 110.

[0119] As Figure 17 shown, the optical path changing portion 116 is provided along a direction parallel to the incident surface 115c. As Figure 18 shown, the optical path changing portion 116 has a triangular pyramid shape and has a reflection surface 116a for reflecting (total reflection) the incident light. The optical path changing portion 116 may also be, for example, a concave portion formed on the back surface 115b of the light guide plate 110. In addition, the optical path changing portion 116 is not limited to the triangular pyramid shape. As Figure 17As shown, on the back surface 115b of the light guide plate 110, a plurality of light path changing unit groups 117a, 117b, 117c... formed by a plurality of light path changing units 116 are formed.

[0120] Figure 19 is a perspective view showing the arrangement of the light path changing units 116. As Figure 19 shown, in each of the light path changing unit groups 117a, 117b, 117c..., the reflecting surfaces 116a of the plurality of light path changing units 116 are arranged on the back surface 115b of the light guide plate 110 such that the angles with respect to the incident direction of light are different from each other. Thus, each of the light path changing unit groups 117a, 117b, 117c... changes the light path of the incident light so that it exits from the exit surface 115a in various directions.

[0121] Next, with reference to Figure 20 , a method for imaging the stereoscopic image I by the light guide plate 110 will be described. Here, a case where the stereoscopic image I as a planar image is imaged on the stereoscopic image imaging surface P which is a surface perpendicular to the exit surface 115a of the light guide plate 110 using the light whose light path is changed by the light path changing unit 116 will be described.

[0122] Figure 20 is a perspective view showing the method for imaging the stereoscopic image I by the light guide plate 110. Here, a case where the inner diagonal ring mark is imaged as the stereoscopic image I on the stereoscopic image imaging surface P will be described.

[0123] As Figure 20 shown, in the light guide plate 110, for example, the light whose light path is changed by each of the light path changing units 116 in the light path changing unit group 117a intersects at lines La1 and La2 on the stereoscopic image imaging surface P. Thus, a part of the stereoscopic image I, that is, the line image LI, is imaged on the stereoscopic image imaging surface P. The line image LI is a line image parallel to the YZ plane. In this way, the line image LI of lines La1 and La2 is imaged using the light from a large number of light path changing units 116 belonging to the light path changing unit group 117a. It should be noted that the light for imaging the images of lines La1 and La2 can be provided by at least two light path changing units 116 in the light path changing unit group 117a.

[0124] Similarly, the light whose light path is changed by each of the light path changing units 116 in the light path changing unit group 117b intersects at lines Lb1, Lb2, and Lb3 on the stereoscopic image imaging surface P. Thus, a part of the stereoscopic image I, that is, the line image LI, is imaged on the stereoscopic image imaging surface P.

[0125] In addition, the light whose optical path has been changed by each optical path changing unit 116 of the optical path changing unit group 117c intersects at lines Lc1 and Lc2 on the stereoscopic image imaging surface P. As a result, a line image LI, which is a part of the stereoscopic image I, is formed on the stereoscopic image imaging surface P.

[0126] The positions of the line images LI in the X-axis direction formed by each of the optical path changing unit groups 117a, 117b, 117c... are different from each other. In the light guide plate 110, by reducing the distances between the optical path changing unit groups 117a, 117b, 117c..., the distances in the X-axis direction of the line images LI formed by each of the optical path changing unit groups 117a, 117b, 117c... can be reduced. As a result, in the light guide plate 110, by integrally using the multiple line images LI formed by the light whose optical path has been changed by each optical path changing unit 116 of the optical path changing unit groups 117a, 117b, 117c..., a surface image, that is, the stereoscopic image I, is actually formed on the stereoscopic image imaging surface P.

[0127] The stereoscopic image imaging surface P may be a plane perpendicular to the X-axis, a plane perpendicular to the Y-axis, or alternatively a plane perpendicular to the Z-axis. Additionally, the stereoscopic image imaging surface P may also be a plane that is not perpendicular to the X-axis, Y-axis, or Z-axis. Furthermore, the stereoscopic image imaging surface P may not be a plane but a curved surface. That is, the light guide plate 110 can form the stereoscopic image I on an arbitrary surface (plane and curved surface) in space by using the optical path changing unit 116. Additionally, by combining multiple surface images, a three-dimensional image can be formed.

[0128] In each of the above embodiments, as an example, the case where the light incident on the exit surface is incident perpendicularly to the exit surface has been described, but the incident angle on the incident exit surface may also be constant.

[0129] 〔Summary〕

[0130] A light guide component according to one aspect of the present invention includes: an incident surface on which light from a light source is incident, at least one reflecting surface that reflects the light incident from the incident surface, and an exit surface formed by a curved surface and that emits the light reflected by the reflecting surface, wherein the reflecting surface reflects the light incident from the light source in a direction such that the incident angle on the exit surface is constant.

[0131] According to the above structure, the light from the light source is reflected by the reflecting surface and travels in a direction having a constant incident angle with respect to the exit surface having a curved surface. That is, by using the light guide component, the light from the light source can be converted into parallel light.

[0132] In addition, based on the light guide component according to one aspect of the present invention, the reflecting surface reflects the light incident from the light source in a direction perpendicular to the exit surface.

[0133] According to the above structure, the light from the light source is the light reflected by the reflecting surface and traveling in a direction perpendicular to the exit surface having a curved surface. That is, by using the light guide member, the light from the light source can be converted into parallel light.

[0134] In addition, in the light guide member according to one aspect of the present invention, the reflecting surface is formed of a plurality of surfaces that reflect the light incident from the incident surface at mutually different angles.

[0135] According to the above structure, by reflecting the light in mutually different directions by the above-mentioned plurality of surfaces, it is possible to reflect the light incident from the light source in a direction where the incident angle to the incident exit surface is constant.

[0136] In addition, in the light guide member according to one aspect of the present invention, when the direction parallel to the incident surface, the reflecting surface, and the exit surface is taken as the thickness direction, the cross-sectional shape of the curved surface perpendicular to the thickness direction is a circular arc, and the cross-sectional shape of the reflecting surface perpendicular to the thickness direction is a plane in which the point symmetric to the light source with respect to the reflecting point coincides with the center point of the circular arc.

[0137] According to the above structure, since the reflecting surface is a plane, it is possible to easily manufacture the light guide member.

[0138] In addition, the light guide member according to one aspect of the present invention has: a plurality of the incident surfaces, and a plurality of the reflecting surfaces respectively corresponding to the plurality of light sources, and the light reflected by each reflecting surface exits from different regions of the exit surface.

[0139] According to the above structure, the incident surface can be arranged close to the light guide plate, and the depth of the light guide member can be shortened.

[0140] In addition, the light guide member according to one aspect of the present invention has a light restricting portion that restricts the range of the light incident from the incident surface so that the light incident from the plurality of incident surfaces irradiates only the corresponding reflecting surface. According to the above structure, it is possible to prevent the generation of stray light.

[0141] In addition, in the light guide member according to one aspect of the present invention, a reflective layer is formed on at least a part of the reflecting surface. According to the above structure, it is possible to form a reflecting surface having a desired function.

[0142] In addition, in the light guide member according to one aspect of the present invention, the reflecting surface is formed such that a straight line connecting an arbitrary point on the reflecting surface and the light source intersects the reflecting surface only at the arbitrary point.

[0143] According to the above structure, since all the light emitted from the light source can be irradiated onto the reflection surface, light can be emitted from all regions of the emission surface in a cross-section perpendicular to the thickness direction.

[0144] In addition, the light guide member according to one embodiment of the present invention has only one incident surface, and the farther the position where the light reflected by the reflection surface is from the light source, the shorter the distance for the light to reach the emission surface.

[0145] According to the above structure, the depth of the light guide member can be shortened.

[0146] In addition, in the light guide member according to one embodiment of the present invention, the reflection surface is formed by a first reflection surface that totally reflects at least a part of the light incident from the incident surface and a second reflection surface that totally reflects at least a part of the light totally reflected by the first reflection surface.

[0147] According to the above structure, the reflection surface does not need to form a reflection layer by metal evaporation or the like, and can reflect the incident light.

[0148] In addition, a lighting device according to one embodiment of the present invention includes: the above light guide member and at least one light source. According to the above structure, the lighting device can provide collimated parallel light in a direction having a constant incident angle with respect to the incident surface of the light guide plate.

[0149] In addition, a display device according to one embodiment of the present invention includes: the above lighting device and a light guide plate that guides the light incident from the lighting device, reflects it by an optical path changing portion formed at a specified position, and emits it from a light emission surface. According to the above structure, the display device can image a stereoscopic image or a planar image as expected.

[0150] In addition, a display device according to one embodiment of the present invention further includes a connection portion that changes the traveling direction of the light emitted from the lighting device between the lighting device and the light guide plate, and the connection portion has a curvature in the traveling direction of the light emitted from the lighting device.

[0151] According to the above structure, the direction in which the light reflected by the reflection surface is guided can be different from the direction in which the light travels in the light guide plate.

[0152] In addition, in the display device according to one embodiment of the present invention, the value obtained by dividing the radius of curvature of the curvature by the thickness of the light guide plate is 3 or more.

[0153] According to the above structure, the light whose traveling direction is changed in the connection portion can enter the light guide plate without leaking to the outside in the connection portion.

[0154] In addition, in a display device according to one aspect of the present invention, the light guide plate uses the light emitted from the light emission surface to form an image in a space outside the light guide plate. With the above-described structure, the display device can form a stereoscopic image as expected.

[0155] In addition, in a display device according to one aspect of the present invention, the light guide plate uses the light emitted from the light emission surface to display a planar image inside the light guide plate. With the above-described structure, the display device can display a planar image.

[0156] The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the technical solutions. Embodiments obtained by appropriately combining the technical methods separately disclosed in different embodiments are also included in the technical scope of the present invention.

[0157] Description of Reference Numerals

[0158] 1 to 5 display devices; 12 to 17 lighting devices; 11, 110 light guide plates; 22 light sources; 120, 130, 140, 150, 160, 170 light guiding members; 113, 116, 117 optical path changing portions (optical path changing portion groups); 116a, 121, 131, 141, 151, 161, 171 reflecting surfaces; 115a, 122, 132, 142, 152, 162, 172 emission surfaces; 11A, 115c, 123, 133, 143, 153, 163, 173 incident surfaces; 144 light restricting portion.

Claims

1. A light guide component, characterized in that, comprising: an incident surface on which light from a light source is incident; at least one reflecting surface that reflects the light incident from the incident surface; an exit surface formed of a curved surface that emits the light reflected by the reflecting surface; the light reflected by the reflecting surface is incident on the exit surface at a constant incident angle; in the case where the direction parallel to the incident surface, the reflecting surface, and the exit surface is taken as the thickness direction, the cross-sectional shape of the curved surface perpendicular to the thickness direction is a circular arc; the cross-sectional shape of the reflecting surface perpendicular to the thickness direction is a plane in which the point that is point-symmetric to the light source with respect to the reflecting point coincides with the center point of the circular arc.

2. The light guide component according to claim 1, characterized in that, the reflecting surface reflects the light incident from the light source in a direction perpendicular to the exit surface.

3. The light guide component according to claim 1 or 2, characterized in that, the reflecting surface is formed of a plurality of surfaces that reflect the light incident from the incident surface at different angles.

4. The light guide component according to claim 1 or 2, characterized in that, comprising: a plurality of the incident surfaces; a plurality of the reflecting surfaces respectively corresponding to the plurality of the incident surfaces; the light reflected by each of the reflecting surfaces exits from respective different regions of the exit surface.

5. The light guide component according to claim 4, characterized in that, comprising: a light restricting portion that restricts the range of the light incident from the incident surface so that the light incident from the plurality of incident surfaces irradiates only the corresponding reflecting surface.

6. The light guide component according to claim 1 or 2, characterized in that, a reflective layer is formed on at least a part of the reflecting surface.

7. The light guide component according to claim 1 or 2, characterized in that, the reflecting surface is formed such that a straight line connecting an arbitrary point on the reflecting surface and the light source intersects the reflecting surface only at the arbitrary point.

8. The light guide component according to claim 1 or 2, characterized in that, only one incident surface is provided, and the farther the position where the light reflected by the reflecting surface is reflected on the reflecting surface is from the light source, the shorter the distance at which the light reaches the exit surface.

9. The light guide component according to claim 1 or 2, characterized in that, the reflecting surface is formed of a first reflecting surface that totally reflects at least a part of the light incident from the incident surface and a second reflecting surface that totally reflects at least a part of the light totally reflected by the first reflecting surface.

10. A lighting device, characterized in that, comprising: a light guiding member according to any one of claims 1 to 9; at least one light source.

11. A display device, characterized in that, comprising: a lighting device according to claim 10; a light guide plate that guides the light incident from the lighting device, reflects the light by an optical path changing portion formed at a specified position, and emits the light from a light exit surface.

12. The display device according to claim 11, characterized in that, a connecting portion that changes the traveling direction of the light emitted from the lighting device is further provided between the lighting device and the light guide plate, the connecting portion has a curvature in the traveling direction of the light emitted from the lighting device.

13. The display device according to claim 12, wherein, the value obtained by dividing the radius of curvature of the curvature by the thickness of the light guide plate is 3 or more.

14. The display device according to any one of claims 11 to 13, wherein, the light guide plate forms an image in a space outside the light guide plate by using the light emitted from the light exit surface.

15. The display device according to any one of claims 11 to 13, wherein, the light guide plate displays a planar image inside the light guide plate by using the light emitted from the light exit surface.

Images