Light source device

Abstract

To provide a light source device which emits light in two different directions with a simple structure.SOLUTION: Light source device 1 includes optical element 20 and light source 10 that emits emission light L toward optical element 20. The optical device 20 integrally includes a plate-shaped main body portion 21 having a first plate surface 21a facing the light sources 10 and inclined with respect to the optical axis of the emission light L, and a plurality of prism portions 22 having a triangular cross-sectional shape and disposed on the first plate surface 21a in a state of being separated from each other. The prism portion 22 has an arrangement surface 21a disposed on the first plate surface 22a, an incident surface 22b on which the emission light L is incident, and a reflecting surface 22b that reflects the emission light L incident from the incident surface 21a toward the first plate surface 22c. An incident angle θ I of the emission light L with respect to the reflecting surface 22c is equal to or larger than a threshold angle.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a light source device. [Background technology]

[0002] Patent Document 1 discloses a headlight with controllable light distribution. The headlight in Patent Document 1 reflects light from a light source using a mirror, and then focuses the reflected light using a lens to irradiate it ahead of the vehicle. The direction of the light irradiation can be adjusted by adjusting the angle of the mirror.

[0003] Patent Document 2 discloses an illumination device including a lamp unit including a light source and an arm connected to the lamp unit. The arm includes a first arm and a second arm connected to be rotatable relative to each other. The lamp unit and the second arm are connected to be rotatable relative to each other. The angle between the first arm and the second arm and the angle between the lamp unit and the second arm are adjusted to adjust the direction in which light from the light source is emitted. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-52584 [Patent Document 2] Japanese Patent Publication No. 2023-63255 Summary of the Invention [Problem to be solved by the invention]

[0005] In the devices disclosed in Patent Documents 1 and 2, the light emission direction is adjustable. On the other hand, there is a demand for a simple structure that can simultaneously emit light in two different directions.

[0006] An object of the present disclosure is to provide a light source device that has a simple structure and that simultaneously emits light in two different directions. [Means for solving the problem]

[0007] The light source device of the present disclosure comprises an optical element and a light source that emits output light toward the optical element, wherein the optical element integrally comprises a plate-shaped main body portion having a first plate surface that faces the light source and is inclined with respect to the optical axis of the output light, and a plurality of prism portions with a triangular cross section that are arranged parallel to and spaced apart from each other on the first plate surface, wherein the prism portions have an arrangement surface that is arranged on the first plate surface, an incident surface onto which the output light is incident, and a reflecting surface that reflects the output light incident from the incident surface toward the first plate surface, and wherein the incident angle of the output light with respect to the reflecting surface is equal to or greater than a critical angle. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a conceptual diagram of a light source device according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a partially enlarged cross-sectional view of the optical element. [Figure 3] FIG. 3 is a partially enlarged view of the optical element shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the components described below can be combined as appropriate.

[0010] It should be noted that the disclosure is merely an example, and appropriate modifications that a person skilled in the art can easily conceive of while maintaining the gist of the present disclosure are naturally included within the scope of the present disclosure. Furthermore, in order to clarify the explanation, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual embodiment, but these are merely examples and do not limit the interpretation of the present disclosure. Furthermore, in this specification and each drawing, elements similar to those described above with respect to the previous drawings may be given the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0011] The X, Y, and Z directions shown in the drawings are perpendicular to one another. The X direction is the depth direction of the light source device 1, the Y direction is the width direction of the light source device 1, and the Z direction is the height direction of the light source device 1. Note that the X, Y, and Z directions are merely examples, and the present disclosure is not limited to these directions. Note that the symbols in parentheses attached to the lines shown in the drawings indicate the direction in which the lines extend.

[0012] 1 is a conceptual diagram of a light source device 1 according to an embodiment of the present disclosure. The light source device 1 simultaneously emits light in two different directions. The light source device 1 is applied, for example, to a backlight for a dual-viewpoint display 2 mounted on a vehicle.

[0013] The dual-viewpoint display 2 is, for example, a liquid crystal display, and displays a first image in a first direction D1 and a second image in a second direction D2. The first direction D1 is a direction from the dual-viewpoint display 2 toward the light-transmitting body 3 (for example, the windshield), and in this embodiment, is the same direction as the Z direction. The first image is projected onto the light-transmitting body 3 and is visually recognized as a virtual image by a passenger M in the driver's seat. The first image is, for example, a symbol indicating the speed and direction of travel of the vehicle.

[0014] The second direction D2 is a direction from the dual-viewpoint display 2 toward the passenger M in the driver's seat. Specifically, the second direction D2 is a direction perpendicular to the Y direction and inclined with respect to the first direction D1. The second image is directly viewed by the passenger M in the driver's seat. The second image is, for example, an image of a map.

[0015] The light source device 1 simultaneously emits light along the first direction D1 and the second direction D2 toward the dual-viewpoint display 2. The first direction D1 and the second direction D2 are different directions as described above. The light source device 1 includes a light source 10 and an optical element 20.

[0016] The light source 10 emits output light L toward the optical element 20. The light source 10 emits the output light L along a first direction D1. That is, the optical axis of the output light L is along the first direction D1 (Z direction). The light source 10 includes, for example, a plurality of light-emitting elements (not shown) such as LEDs (Light Emitting Diodes) that emit light along the first direction D1.

[0017] The optical element 20 splits the traveling direction of the light L emitted from the light source 10 into a first direction D1 and a second direction D2. The light emitted from the optical element 20 corresponds to the light emitted from the light source device 1. The optical element 20 is translucent. The optical element 20 is made of, for example, a thermoplastic resin or glass.

[0018] 2 is a partially enlarged cross-sectional view of the optical element 20. The optical element 20 integrally includes a main body 21 and a plurality of prism portions 22.

[0019] The main body 21 is plate-shaped and has a first plate surface 21a facing the light source 10 and a second plate surface 21b opposite the first plate surface 21a. The first plate surface 21a is a flat surface inclined with respect to the optical axis of the emitted light L. In this embodiment, the first plate surface 21a is parallel to the Y direction and inclined with respect to the X direction and the first direction D1 (Z direction). The inclination angle θt formed between the first plate surface 21a and the X direction is, for example, not less than 10° and not more than 70°. It goes without saying that the inclination angle θt is not limited to this angle.

[0020] The second plate surface 21b is a plane parallel to the first plate surface 21a.

[0021] The prism portion 22 has a triangular prism shape extending along the central axis Ax. The prism portion 22 has a triangular cross section. The multiple prism portions 22 are arranged apart from each other on the first plate surface 21a. The central axes Ax of the multiple prism portions 22 extend along the Y direction and are parallel to each other. The multiple prism portions 22 are lined up in a parallel state to each other.

[0022] The prism portion 22 has an arrangement surface 22a, an incident surface 22b, and a reflecting surface 22c, which are all parallel to the Y direction.

[0023] The arrangement surface 22a is arranged on the first plate surface 21a. That is, the arrangement surface 22a and the first plate surface 21a are arranged on the same plane.

[0024] The incident surface 22b faces the light source 10. The light L emitted from the light source 10 is incident on the incident surface 22b.

[0025] The reflecting surface 22c reflects the output light L incident from the incident surface 22b toward the first plate surface 21a. The incident angle θi of the output light L with respect to the reflecting surface 22c is equal to or greater than the critical angle of the reflecting surface 22c. In other words, the reflecting surface 22c totally reflects the output light L.

[0026] The prism portions 22 are arranged at equal intervals in an arrangement direction D3 that is perpendicular to the Y direction and parallel to the first plate surface 21a.

[0027] In the arrangement direction D3, the interval P between two adjacent prism portions 22 corresponds to the distance between the central axes Ax of the two prism portions 22. The light L emitted from the light source 10 is directly incident on the first plate surface 21a from between the two adjacent prism portions 22.

[0028] Next, a description will be given of the separation of the light L emitted from the light source 10 in the optical element 20. First, the light L emitted from the light source 10 that is directly incident on the first plate surface 21a of the main body portion 21 will be described.

[0029] The emitted light L from the light source 10 is directly incident on the main body 21 from a first region R1 on the first plate surface 21a. When the main body 21 is viewed along the first direction D1, the first region R1 corresponds to a region on the first plate surface 21a between a first side S1 between the incident surface 22b and the reflecting surface 22c of one of the two adjacent prism portions 22 and a second side S2 between the incident surface 22b of the other prism portion 22 and the first plate surface 21a. Hereinafter, the emitted light L from the light source 10 that is directly incident on the main body 21 from the first region R1 on the first plate surface 21a will be referred to as the "first emitted light L1."

[0030] The first outgoing light L1 is refracted at the first plate surface 21a in accordance with the refractive index of the optical element 20, and travels inside the main body 21. Furthermore, the first outgoing light L1 is refracted at the second plate surface 21b, and is emitted from the main body 21 along the first direction D1.

[0031] Next, the output light L from the light source 10 that enters through the incident surface 22b of the prism section 22 will be described. The output light L that enters through the incident surface 22b is refracted according to the refractive index of the optical element 20 and travels through the prism section 22. A portion of the output light L that enters through the incident surface 22b is reflected by the reflecting surface 22c. Hereinafter, the output light L from the light source 10 that enters through the incident surface 22b and is reflected by the reflecting surface 22c will be referred to as the "second output light L2."

[0032] That is, the second outgoing light L2 enters the prism portion 22 from the second region R2 of the incident surface 22b. The second region R2 is a region where the outgoing light L (second outgoing light L2) incident from the incident surface 22b travels toward the reflecting surface 22c.

[0033] As described above, the second outgoing light L2 is totally reflected by the reflecting surface 22c. The totally reflected second outgoing light L2 travels through the prism portion 22 and the main body portion 21, is refracted at the second plate surface 21b, and is emitted from the main body portion 21. The second outgoing light L2 is emitted along the second direction D2.

[0034] Fig. 3 is a partially enlarged view of the optical element 20 shown in Fig. 2. The separation angle θs between the first direction D1 in which the first output light L1 emitted from the light source device 1 travels and the second direction D2 in which the second output light L2 emitted from the light source device 1 travels is expressed by the following equations (1), (2), (3), (4), and (5). In other words, the desired separation angle θs can be determined based on equations (1), (2), (3), (4), and (5).

[0035] φ1=θ1-θt (1) sinφ1=n×sinφ2 (2) φ3=θ1+θ2-φ2-90° ···(3) φ4=φ3+θ2-90° (4) θs=θt+sin -1 (n×sinφ4) (5)

[0036] In equations (1), (2), (3), (4), and (5), φ1 is the angle of incidence of the second output light L2 with respect to the incident surface 22b, φ2 is the angle of refraction of the second output light L2 with respect to the incident surface 22b, φ3 is the angle between the direction in which the second output light L2 incident on the reflecting surface 22c travels and the reflecting surface 22c, and φ4 is the angle of incidence of the second output light L2 with respect to the second plate surface 21b. Also, n is the refractive index of the optical element 20, θ1 is the angle between the incident surface 22b and the arrangement surface 22a (hereinafter referred to as the first prism angle θ1: equivalent to the "second angle"), and θ2 is the angle between the reflecting surface 22c and the arrangement surface 22a (hereinafter referred to as the second prism angle θ2).

[0037] Furthermore, the light intensity of the first output light L1 and the light intensity of the second output light L2 can be adjusted by the interval P between two adjacent prism portions 22 in the arrangement direction D3. As shown in Fig. 1, when the first image is viewed as a virtual image and the second image is viewed directly, it is desirable that the first image be brighter than the second image.

[0038] 2, the larger the distance P between the two prism portions 22, the larger the first region R1 becomes, and the greater the amount of light of the first output light L1 becomes. On the other hand, as the distance P between the two prism portions 22 and the length w of the arrangement surface 22a in the arrangement direction D3 increase, the first output light L1 becomes more easily visible in a divided state. Therefore, it is desirable that the distance P between the two prism portions 22 and the length w of the arrangement surface 22a in the arrangement direction D3 be small.

[0039] Therefore, in this case, the ratio of the length w of the arrangement surface 22a to the interval P between two adjacent prism portions 22 in the arrangement direction D3 is set to be equal to or greater than 0.50 and equal to or less than 0.95. This prevents the first output light L1 from being perceived as being split, while making the amount of light of the first output light L1 greater than the amount of light of the second output light L2. It goes without saying that the ratio of the length w of the arrangement surface 22a to the interval P between two adjacent prism portions 22 in the arrangement direction D3 is not limited to be equal to or greater than 0.50 and equal to or less than 0.95. It goes without saying that, in this embodiment, the interval P between two adjacent prism portions 22 is approximately 20 μm to 1000 μm, and the length w of the arrangement surface 22a is approximately 5 μm to 100 μm, but is not limited to these values.

[0040] Although preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to such embodiments. The contents disclosed in the embodiments are merely examples, and various modifications are possible within the scope of the present disclosure. Appropriate modifications made within the scope of the present disclosure also naturally fall within the technical scope of the present disclosure.

[0041] For example, the intervals between the multiple prism portions 22 are not limited to being equal intervals.

[0042] Alternatively, the first prism angle θ1 and the second prism angle θ2 may be determined so that the ray angle θr (corresponding to the "first angle") between the direction in which the second output light L2 reflected by the reflecting surface 22c shown in FIG. 3 travels and the first plate surface 21a is equal to or greater than the first prism angle θ1 between the incident surface 22b and the first plate surface 21a. In this case, the second output light L2 reflected by the reflecting surface 22c is emitted from the second plate surface 21b without traveling toward the incident surface 22b. On the other hand, if the ray angle θr is smaller than the first prism angle θ1, a portion of the second output light L2 reflected by the reflecting surface 22c is incident on the incident surface 22b and emitted in a direction different from the second direction D2. In other words, when the ray angle θr is equal to or greater than the first prism angle θ1, the second output light L2 can be effectively utilized. The first prism angle θ1 is approximately 50° to 90°, and the second prism angle θ2 is approximately 50° to 80°, but needless to say, they are not limited to these values.

[0043] Alternatively, the first prism angle θ1 and the second prism angle θ2 may be determined so that the light ray angle θr is equal to the first prism angle θ1. Note that the light ray angle θr shown in FIG. 3 is equal to the first prism angle θ1.

[0044] 3, when the inclination of the reflecting surface 22c is changed by rotating the reflecting surface 22c around the first side S1 so as to increase the second prism angle θ2 without changing the first prism angle θ1, the light ray angle θr increases and the second region R2 becomes smaller. On the other hand, when the light ray angle θr is equal to or greater than the first prism angle θ1, the second region R2 becomes larger as the light ray angle θr decreases. In other words, when the light ray angle θr is equal to or greater than the first prism angle θ1, the second region R2 is maximized when the light ray angle θr is equal to the first prism angle θ1. Therefore, by making the light ray angle θr equal to the first prism angle θ1, the output light L from the light source 10 can be effectively utilized.

[0045] Furthermore, it goes without saying that light source device 1 may be applied to devices other than the dual-viewpoint display 2 shown in FIG. 1. For example, it may be applied to a dual-viewpoint display that is mounted in a vehicle and displays a first image toward a passenger in the driver's seat and a second image toward a passenger in the front passenger's seat. In this case, light source device 1 emits light in two directions: one from the dual-viewpoint display toward the passenger in the driver's seat, and the other from the dual-viewpoint display toward the passenger in the front passenger's seat. Furthermore, light source device 1 may be a lighting device that emits light in two different directions.

[0046] Furthermore, other effects and advantages brought about by the aspects described in this embodiment that are clear from the description in this specification or that can be appropriately thought of by a person skilled in the art are naturally understood to be brought about by the present disclosure. [Explanation of symbols]

[0047] 1 Light source device 10 light source 20 Optical Elements 21 Main body 21a 1st plate surface 21b 2nd plate surface 22 Prism section 22a Placement surface 22b Incidence plane 22c reflective surface D1 1st direction D2 2nd direction D3 Array Direction L Output light P is the distance between two adjacent prisms w is the length of the prism arrangement surface in the arrangement direction θ1 First prism angle (second angle) θ2 Second prism angle θi Incident angle of the emitted light to the reflecting surface θr Ray angle (first angle) θs separation angle θt Tilt angle

Claims

1. an optical element; a light source that emits output light toward the optical element, The optical element is a plate-shaped main body having a first plate surface facing the light source and inclined with respect to the optical axis of the emitted light; a plurality of prism portions each having a triangular cross section and arranged apart from one another on the first plate surface, The prism portion is an arrangement surface disposed on the first plate surface; an incident surface onto which the emitted light is incident; a reflecting surface that reflects the outgoing light incident from the incident surface toward the first plate surface, an incident angle of the emitted light with respect to the reflecting surface is equal to or greater than a critical angle of the reflecting surface; Light source device.

2. the main body portion has a second plate surface opposite to the first plate surface, The second plate surface is a plane parallel to the first plate surface. The light source device according to claim 1 .

3. In an arrangement direction in which the plurality of prism portions are arranged, a ratio of a length of the arrangement surface of the prism portion to a distance between two adjacent prism portions is 0.50 or more and 0.95 or less. The light source device according to claim 1 .

4. a first angle formed between the direction in which the emitted light reflected by the reflecting surface travels and the first plate surface is equal to or greater than a second angle formed between the incident surface and the first plate surface; The light source device according to claim 1 .

5. The first angle is equal to the second angle. The light source device according to claim 4 .

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