Light guide body, light source device, illuminating device, and moving body

Abstract

To restrain light from a light source from leaking to the side of a first surface of a light guide body.SOLUTION: A light guide plate 1 comprises: an incidence surface 10 on which light emitted from a light source 2 is incident; a first surface 11 for reflecting the light incident from the incidence surface 10; a second surface 12 provided so as to be opposed to the first surface 11, and emitting the light incident from the first surface 11; a first polarization part provided on the incidence surface 10, and allowing the light in a first polarization direction to pass, and preventing the light in a second polarization direction from passing; a second polarization part provided on the first surface 11, and allowing the light in the second polarization direction to pass, and preventing the light in the first polarization direction from passing; and a plurality of prisms 3 provided in at least one of the first surface 11 and the second surface 12, and reflecting the incident light toward the second surface 12.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a light guide, a light source device, an illumination device, and a moving object. [Background technology]

[0002] 2. Description of the Related Art Illumination devices that illuminate a sunroof of a vehicle have been known.

[0003] The lighting device of Patent Document 1 has a light guide layer provided on the surface of a sunroof glass. A pattern is formed on a first surface (surface facing the outside of the vehicle) of the light guide layer. Light from a light source is reflected by the pattern formed on the first surface of the light guide layer toward a second surface (surface facing the inside of the vehicle). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 1,108,419 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the configuration of Patent Document 1, the pattern does not cover the entire first surface, so there is a risk that light from the light source may leak onto the first surface side.

[0006] Therefore, an object of the present disclosure is to provide a light guide, a light source device, an illumination device, and a moving body that can prevent light from a light source from leaking to the first surface side of the light guide. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, a light guide according to one embodiment of the present disclosure comprises an incident surface onto which light emitted from a light source is incident, a reflecting surface that reflects the light incident from the incident surface, an exit surface that is arranged opposite the reflecting surface and that emits the light incident from the incident surface, a first polarization section that is arranged on the incident surface and transmits light of a first polarization direction and does not transmit light of a second polarization direction, a second polarization section that is arranged on the reflecting surface and transmits light of the second polarization direction and does not transmit light of the first polarization direction, and a plurality of prisms that are arranged on at least one of the reflecting surface and the exit surface and reflect the incident light toward the exit surface. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to prevent light from the light source from leaking to the first surface side of the light guide. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a plan view of an illumination device according to a first embodiment. [Figure 2] FIG. 1 is a side view of an illumination device according to a first embodiment. [Figure 3] FIG. 10 is a side view of a lighting device according to a modified example of the first embodiment. [Figure 4] FIG. 10 is a side view of the lighting device according to the second embodiment. [Figure 5] FIG. 10 is a side view of the lighting device according to the third embodiment. [Figure 6] FIG. 11 is a side view of an illumination device according to a modified example of the third embodiment. [Figure 7] FIG. 10 is a side view of a lighting device according to a fourth embodiment. [Figure 8] FIG. 11 is a side view of an illumination device according to a fifth embodiment. [Figure 9] FIG. 13 is a side view of the lighting device according to the sixth embodiment. [Figure 10] FIG. 13 is a side view of an illumination device according to a seventh embodiment. [Figure 11] FIG. 13 is a side view of an illumination device according to a modified example of the seventh embodiment. [Figure 12] FIG. 10 is a side view of a lighting device according to another embodiment. [Figure 13] FIG. 10 is a side view of a lighting device according to another embodiment. [Figure 14] FIG. 10 is a side view of a lighting device according to another embodiment. [Figure 15] 1 is a schematic diagram of a moving body equipped with a lighting device. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiment is essentially merely illustrative and is not intended to limit the present invention, its applications, or its uses. In the following description, the same parts will be designated by the same reference numerals, and detailed description will be omitted as appropriate.

[0011] (First embodiment) FIG. 1 is a plan view of the lighting device according to the first embodiment, and FIG. 2 is a side view of the lighting device according to the first embodiment. As shown in FIGS. 1 and 2, the lighting device 100 includes a light guide plate 1 (light guide) and a plurality of light sources 2. In the following description, the optical axis direction of the light source 2 is defined as the X direction, the direction in which the plurality of light sources 2 are arranged as the Y direction, and the thickness direction of the light guide plate 1 as the Z direction. In FIG. 2 and other figures, the light emitted from the light source 2 is indicated by a dashed arrow. The light guide 1 and the plurality of light sources 2 correspond to a light source device.

[0012] The light guide plate 1 is a generally plate-shaped member made of a light-transmitting material such as resin or glass. Examples of resin materials that make up the light guide plate 1 include polypropylene, polyethylene, polyethylene terephthalate, polyvinyl chloride, ABS resin, acrylic, polyamide, polycarbonate, and Teflon (registered trademark). Examples of glass materials that make up the light guide plate 1 include BK7, synthetic quartz for excimer lasers, synthetic quartz, and anhydrous synthetic quartz.

[0013] The light source 2 is, for example, a solid-state light-emitting element such as a light-emitting diode (LED) element or an organic electro-luminescence (OEL) element. In this embodiment, the light source 2 is, for example, a chip-shaped light-emitting diode element. The light source 2 is arranged on the incident surface 10 side (the surface on the right side in the drawing) of the light guide plate 1, and irradiates the light guide plate 1 with light.

[0014] 2, the light guide plate 1 has a first surface 11 and a second surface 12. The first surface 11 and the second surface 12 are flat surfaces that face each other.

[0015] A plurality of prisms 3 are formed on the first surface 11 of the light guide plate 1. The prisms 3 are formed in a concave shape on the first surface 11 and are hollow inside. Each prism 3 is formed to extend in the Y direction (see FIG. 1).

[0016] Each prism 3 reflects incident light from the light source 2 toward the second surface 12. Therefore, the incident light that enters the light guide plate 1 from the light source 2 is emitted from the second surface 12. In other words, the light guide plate 1 includes a so-called direct optical path in which the incident light that enters the incident surface 10 from the light source 2 is directly reflected by the prisms formed on the first surface 11 and emitted from the second surface.

[0017] A polarizing plate 4 (first polarizing portion) is provided on the incident surface 10 of the light guide plate 1. The polarizing plate 4 transmits only P-polarized light (light in a first polarization direction) and does not transmit (absorbs) S-polarized light (light in a second polarization direction). Because the polarizing plate 4 absorbs S-polarized light, only P-polarized light enters the light guide plate 1 out of the light that has entered the incident surface 10 of the light guide plate 1 from the light source 2.

[0018] A polarizing plate 5 (second polarizing section) is provided on the first surface 11 of the light guide plate 1. The polarizing plate 5 transmits only S-polarized light and does not transmit (absorbs) P-polarized light. As described above, the polarizing plate 4 allows only P-polarized light to enter the light guide plate 1 from the light source 2. Therefore, the P-polarized light that is not reflected by the prism 3 on the first surface 11 of the light guide plate 1 is absorbed by the polarizing plate 5. This makes it possible to prevent light from the light source from leaking outside the first surface 11 of the light guide plate 1 (to the upper side of the drawing in FIG. 2).

[0019] Furthermore, by forming an air layer between the first surface 11 of the light guide plate 1 and the polarizing plate 5, the P-polarized light incident on the polarizing plate 5 can be reflected to the second surface 12 side (the lower side in the drawing), thereby improving the optical efficiency of the light guide plate 1.

[0020] Furthermore, because polarizing plate 5 transmits S-polarized light, a portion of the light that enters first surface 11 from the outside of light guide plate 1 (upper side in the drawing) is not absorbed by polarizing plate 5 and is transmitted through light guide plate 1. For this reason, when looking from the inside of light guide plate 1 (second surface 12 side, lower side in the drawing) to the outside (first surface 11 side, upper side in the drawing), the outside scenery can be seen. In particular, if prism 3 is a fine prism with a hollow interior, prism 3 is less likely to block the outside scenery when viewed.

[0021] (Variation) Fig. 3 is a side view of an illumination device according to a modification of the first embodiment. In Fig. 3, the prism 3 is formed on the second surface 12 side.

[0022] As shown in Fig. 3, polarizing plate 5 reflects P-polarized light incident from polarizing plate 4 (incident surface 10 of light guide plate 1) toward second surface 12. As described above, by forming an air layer between first surface 11 of light guide plate 1 and polarizing plate 5, P-polarized light incident on polarizing plate 5 can be reflected toward second surface 12. The P-polarized light reflected by polarizing plate 5 is emitted from second surface 12 of light guide plate 1 by prism 3 formed on the second surface 12 side.

[0023] The configuration of FIG. 3 also provides the same effects as those of FIG.

[0024] Alternatively, the P-polarized light incident on the light guide plate 1 through the incident surface 10 may be incident directly on the prism 3 without passing through the polarizing plate 5, and may be emitted from the second surface 12 of the light guide plate 1.

[0025] (Second embodiment) 4 is a side view of an illumination device according to Embodiment 2. In the second embodiment, an illumination device 100 includes a sheet member 6. As shown in FIG.

[0026] As shown in FIG. 4, a sheet member 6 is provided on the first surface 11 side of the light guide plate 1. The sheet member 6 is a member made of a light-transmitting material such as resin or glass, and is formed so as to become thinner in the thickness direction. The sheet member 6 includes those formed in a thin shape, such as a flat plate, sheet, or film. In the second embodiment, a plurality of prisms 3 are formed on the sheet member 6.

[0027] In Figure 4, by forming multiple prisms 3 on a sheet member 6 that is a separate member from the light guide plate 1, there is no need to form prisms 3 on the light guide plate 1 itself, so it is possible to make the light guide plate 1 from a material other than resin.

[0028] The sheet member 6 may be provided on the second surface 12 of the light guide plate 1.

[0029] (Third embodiment) 5 is a side view of an illumination device according to Embodiment 3. In the third embodiment, an illumination device 100 includes a collimator lens 7 (first polarization unit) and a polarizing converter 8 (first polarization unit).

[0030] As shown in Figure 5, the collimating lens 7 is positioned between the light source 2 and the incident surface 10 of the light guide plate 1, and is a lens that collects light incident from the light source 2 and makes it incident on the incident surface 10 of the light guide plate 1.

[0031] The polarizing converter 8 is provided on the incident surface 10 of the light guide plate 1, and converts S-polarized light into P-polarized light among the light incident from the collimator lens 7 (light source 2), and transmits the P-polarized light.

[0032] 5, by providing the illumination device 100 with a collimating lens 7, the light incident from the light source 2 can be focused onto the incident surface 10 of the light guide plate 1, thereby improving the light utilization efficiency of the illumination device. Furthermore, by providing the illumination device 100 with a polarizing converter 8, the P-polarized light of the light incident from the light source 2 can be converted into S-polarized light, thereby improving the light utilization efficiency of the illumination device.

[0033] As shown in FIG. 6, a polarizing plate 4 may be provided between the polarizing converter 8 and the incident surface 10 of the light guide plate 1.

[0034] (Fourth embodiment) 7 is a side view of an illumination device according to Embodiment 4. In the fourth embodiment, an illumination device 100 includes a liquid crystal member 9. As shown in FIG.

[0035] The liquid crystal member 9 is a member containing liquid crystal whose optical properties change when a voltage is applied. The liquid crystal member 9 is formed in the shape of, for example, a flat plate, a sheet, or a film so as to be thin in the thickness direction.

[0036] 7, the liquid crystal member 9 is provided on the second surface 12 side of the light guide plate 1. The liquid crystal member 9 is controlled by a control device (not shown), and displays an image by partially blocking or transmitting light incident from the second surface 12 side of the light guide plate 1.

[0037] In FIG. 7, by providing the lighting device 100 with a liquid crystal member 9, the light incident on the light guide plate 1 from the light source 2 can be used as a backlight, and therefore the lighting device 100 can be used as a display device.

[0038] (Fifth embodiment) 8 is a side view of an illumination device according to Embodiment 5. In the fifth embodiment, an illumination device 100 includes a light control member 21. As shown in FIG.

[0039] The light adjusting member 21 is a member that switches between transparent and opaque when a voltage is applied to it. The light adjusting member 21 is formed in the shape of, for example, a flat plate, a sheet, or a film so as to become thinner in the thickness direction.

[0040] 8, the light adjusting member 21 is provided on the first surface 11 side of the light guide plate 1. The light adjusting member 21 is controlled by a control device (not shown), and blocks light from reaching the outside of the light guide plate 1 (the first surface 11 side, the upper side of the drawing) when the light source 2 is turned on.

[0041] In FIG. 8, the lighting device 100 is provided with the light control member 21, which can further prevent light from the light source 2 from leaking outside the first surface 11 of the light guide plate 1.

[0042] (Sixth embodiment) 9 is a plan view of an illumination device according to a sixth embodiment. The sixth embodiment differs from the first embodiment in the arrangement of the prisms 3.

[0043] 9, the multiple prisms 3 are arranged to form the letter "A" in a plan view. When the light source 2 is turned on, the light from the light source 2 is reflected by the multiple prisms 3, and the letter "A" is displayed on the light guide plate 1. In other words, by arranging the multiple prisms 3 in a desired letter, design, shape, etc., it is possible to display a desired letter, etc. on the light guide plate 1.

[0044] (Seventh embodiment) FIG. 10 is a plan view showing the lighting device according to the seventh embodiment, and FIG. 11 is a side view showing the lighting device according to the seventh embodiment.

[0045] 10 and 11, the light guide plate 1 is provided with two incident surfaces (incident surfaces 10a and 10b), and a plurality of light sources 2a and 2b are provided corresponding to the incident surfaces 10a and 10b, respectively.

[0046] The plurality of prisms 3 also includes a plurality of prisms 3a and a plurality of prisms 3b.

[0047] The multiple prisms 3a are arranged so as to form the letter "A" in a plan view. The angle and direction of the prisms 3a are set so as to reflect light that has entered the light guide plate 1 through the incident surface 10a.

[0048] The multiple prisms 3b are arranged so as to form the letter "B" in a plan view. The angle and direction of the prisms 3b are set so as to reflect light that has entered the light guide plate 1 through the incident surface 10b.

[0049] As a result, when light source 2a is turned on, light emitted from light source 2a enters light guide plate 1 through incident surface 10a and is reflected by prism 3a, thereby displaying the letter "A" on light guide plate 1. When light source 2b is turned on, light emitted from light source 2b enters light guide plate 1 through incident surface 10b and is reflected by prism 3b, thereby displaying the letter "B" on light guide plate 1. Therefore, when multiple incident surfaces are formed on light guide plate 1, multiple desired characters can be displayed on light guide plate 1 by appropriately setting the orientation and angle of each prism 3. Note that in FIGS. 10 and 11, up to four desired characters can be displayed on light guide plate 1. In this case, light sources and incident surfaces can be disposed and formed at the top and bottom of the drawing, respectively, and prisms corresponding to the light sources and incident surfaces can be formed.

[0050] (Other embodiments) As described above, the embodiments have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to these, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate.

[0051] Fig. 12 is a side view of an illumination device according to another embodiment. In Fig. 12, a resin with a predetermined refractive index (low refractive index) is filled inside all or part of the multiple prisms 3. This increases the strength of the light guide plate 1.

[0052] Fig. 13 is a side view of an illumination device according to another embodiment. In Fig. 13, the first surface 11 and the second surface 12 of the light guide plate 1 are curved. Even with this light guide plate 1, the configurations of the above-described embodiments are applicable.

[0053] Fig. 14 is a plan view of an illumination device according to another embodiment. In Fig. 14, a plurality of prisms 3 are arranged in an arc shape. That is, some of the plurality of prisms 3 may have different arrangement directions or angles. Furthermore, some of the plurality of prisms 3 may have different sizes (depths) in the Z direction.

[0054] FIG. 15 is a schematic diagram of a moving body equipped with an illumination device. As shown in FIG. 15, the illumination device 100 is disposed in a moving body 200 (here, a vehicle). Specifically, the light guide plate 1 in the illumination device 100 is provided as a sunroof for the moving body 200. By providing the illumination device 100 in the moving body 200, it is possible to illuminate the sunroof of the moving body 200 while suppressing leakage of light from the light source 2 of the illumination device 100 to the outside of the moving body 200, and it is also possible to view the scenery outside the moving body 200 from inside the moving body 200. Note that the moving body 200 is not limited to a vehicle, and may be, for example, a large vehicle such as a truck or a bus, a motorcycle, a train, an electric cart, construction machinery, an aircraft, a ship, or the like. Furthermore, the illumination device 100 may be any of the illumination devices in the above-described embodiments and modified examples.

[0055] In the above embodiments and modifications, the polarizing plate 4 and the polarizing converter 8 are polarizing plates that transmit only P-polarized light and do not transmit (absorb) S-polarized light, and the polarizing plate 5 is a polarizing plate that transmits only S-polarized light and does not transmit (absorb) P-polarized light, but this is not limiting. The polarizing plate 4 and the polarizing converter 8 may be polarizing plates that transmit only S-polarized light and do not transmit (absorb) P-polarized light, and the polarizing plate 5 may be a polarizing plate that transmits only P-polarized light and does not transmit (absorb) S-polarized light.

[0056] Furthermore, in the above embodiment and modified examples, the polarizing plate 4 and the polarizing converter 8 have been described as examples of the first polarization section, but this is not limiting, and the first polarization section may include an optical element or the like that transmits only light in the first polarization direction and does not transmit (absorbs) light in the second polarization direction. Similarly, in the above embodiment and modified examples, the polarizing plate 5 has been described as an example of the second polarization section, but this is not limiting, and the second polarization section may include an optical element or the like that transmits only light in the second polarization direction and does not transmit (absorbs) light in the first polarization direction.

[0057] Furthermore, in the above-described embodiments and modifications, the light guide plate 1 is described as an example of a light guide, but the light guide is not limited to the light guide plate 1. The light guide may be any optical element having optical properties corresponding to the above-described embodiments and modifications. [Industrial Applicability]

[0058] The light guide plate of the present disclosure can be applied to, for example, the sunroof of a vehicle. [Explanation of symbols]

[0059] 1 Light guide plate (light guide, light source device) 2,2a,2b Light source (light source device) 3,3a,3b Prism 4 Polarizing plate (first polarizing part) 5 Polarizing plate (second polarizing part) 6 Sheet material 7 Collimating Lens 8 Polarizing converter (first polarization section) 9 Liquid crystal components 10,10a,10b entrance plane 11 1st surface (reflective surface) 12 Second surface (exit surface) 21 Light control components 100 lighting equipment 200 Mobile

Claims

1. an incident surface onto which light emitted from the light source is incident; a reflecting surface that reflects light incident from the incident surface; an exit surface that is provided opposite the reflecting surface and that emits light that has entered through the incident surface; a first polarization unit provided on the incident surface, the first polarization unit transmitting light having a first polarization direction and not transmitting light having a second polarization direction; a second polarization unit provided on the reflecting surface, the second polarization unit transmitting light in the second polarization direction and not transmitting light in the first polarization direction; a plurality of prisms provided on at least one of the reflecting surface and the emitting surface, which reflect incident light toward the emitting surface.

2. The light guide according to claim 1 , wherein the plurality of prisms are formed on a sheet member.

3. The light guide according to claim 1 , wherein the first polarizing section includes a polarizing converter that converts incident light in the second polarization direction into light in the first polarization direction.

4. The light guide according to claim 1 , further comprising a liquid crystal member provided on the light exit surface.

5. The light guide according to claim 1 , further comprising a light control member provided on the reflecting surface side.

6. The light guide according to claim 1 ; a light source device comprising the light source.

7. The first polarization unit a collimating lens that condenses light from the light source; 7. The light source device according to claim 6, further comprising a polarizing converter that converts the light in the second polarization direction incident from the collimator lens into light in the first polarization direction.

8. An illumination device comprising the light source device according to claim 6.

9. The light guide according to claim 1 ; and the light source.

Images