Lighting device

Abstract

To provide a lighting device allowing for easily discriminating lighting states.SOLUTION: A lighting device according to an embodiment comprises: a plurality of light sources; a plurality of light distribution lenses each provided on each of the light sources; a light guide body configured to guide a part of light from the respective light distribution lenses emit a part of light which comes from the respective light distribution lenses, while emitting, from a first emission surface, a part of the light which comes from the respective light distribution lenses, wherein the first emission surface includes at least a part of a surface facing the light distribution lens in a second surface opposite to a first surface where the respective light distribution lenses are disposed separatedly from each other; and a plurality of natural lighting parts each one of which is provided on each one of the light distribution lenses, and which is configured to take in the light guided through the light guide body, and emit the light from a second emission surface.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE The present invention relates to a lighting device. [Background technology]

[0002] Various types of lighting are known for the interior of an automobile (see, for example, Patent Documents 1 and 2). Known types of lighting provided on the ceiling of the interior of the automobile include, for example, room lighting that illuminates the entire area of ​​the driver's seat and passenger seat, and spot lighting that illuminates each of the driver's seat and passenger seat.

[0003] Each seat is provided with its own spotlight and a switch to turn the spotlight on and off. The switching of each switch is performed based on the visual confirmation of the lighting status (on or off) of the lighting for each seat.

[0004] For example, spot lighting with bulb light sources has a large light emitting part (lens), and many of these light emitting parts are equipped with a switch function. In spot lighting of this type, the switching of each switch is directly operated by visually checking each light emitting part that also has the function of each switch.

[0005] In addition, in spot lighting using LED (Light Emitting Diode) light sources, the light-emitting unit and the switch are often separate components. For this reason, the driver's seat switch is operated by visually checking the light-emitting unit on the driver's seat side, and the passenger's seat switch is operated by visually checking the light-emitting unit on the passenger's seat side. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2013-237384 A [Patent Document 2] JP 2014-113828 A Summary of the Invention [Problem to be solved by the invention]

[0007] In recent years, the size of lighting devices in vehicle cabins has been reduced. As spotlights become smaller, the light-emitting unit on the driver's seat side and the light-emitting unit on the passenger seat side may be placed close to each other, or both light-emitting units may be concentrated in one place. In such cases, it becomes difficult to accurately visually confirm the lighting state of each light-emitting unit, which may lead to confusion when switching between switches. In particular, when a touch switch is used, it is difficult to determine the lighting state because the lighting state cannot be confirmed by the shape or switching position of the switch as with a physical switch.

[0008] The present invention has been made in view of the above, and has an object to provide a lighting device whose lighting state can be easily determined. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems and achieve the object, an illumination device according to one embodiment of the present invention includes a plurality of light sources, a plurality of light distribution lenses, one for each light source, a light guide on a first surface on which the light distribution lenses are spaced apart and which emits a portion of light from each light distribution lens from a first exit surface including at least a portion of a surface of a second surface opposite the first surface that faces the light distribution lens, and guides a portion of the light from each light distribution lens, and a plurality of light collecting sections, one for each light distribution lens, which collect light guided within the light guide and emit it from the second exit surface.

[0010] ADVANTAGE OF THE DRAWINGS FIG. 1 is a block diagram showing an illumination device according to an embodiment of the present invention; FIG. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view of a lighting device according to an embodiment. [Diagram 2] FIG. 2 is a perspective view of a lighting device according to an embodiment. [Diagram 3]FIG. 3 is a front view of the lighting device according to the embodiment. [Figure 4] FIG. 4 is a side view of the lighting device according to the embodiment. [Diagram 5] FIG. 5 is an enlarged view of the front view of FIG. [Figure 6] FIG. 6 is a diagram showing an example of light emission from a light source in a front view of the lighting device. [Figure 7] FIG. 7 is a perspective view of an illumination device according to the first modification. [Figure 8] FIG. 8 is an enlarged front view of an illumination device according to the second modification. [Figure 9] FIG. 9 is an enlarged front view of an illumination device according to the third modification. [Figure 10] FIG. 10 is a perspective view of an illumination device according to the fourth modification. [Figure 11] FIG. 11 is a perspective view of an illumination device according to the fifth modification. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, a lighting device according to an embodiment will be described with reference to the drawings. Note that the present invention is not limited to this embodiment. In addition, the dimensional relationship of each element in the drawings, the ratio of each element, etc. may differ from reality. Even between the drawings, there may be parts in which the dimensional relationship and ratio differ from each other. In addition, the contents described in one embodiment or modified example are, in principle, similarly applied to other embodiments or modified examples.

[0013] (Embodiment) The configuration of the lighting device 1 according to the embodiment will be described with reference to Figs. 1 to 5. Fig. 1 is a perspective view 1 of the lighting device 1 according to the embodiment, as viewed from the back side of the light-emitting surface. Fig. 2 is a perspective view 2 of the lighting device 1 according to the embodiment, as viewed from the light-emitting surface side. Fig. 3 is a front view of the lighting device 1 according to the embodiment. Fig. 4 is a side view of the lighting device 1 according to the embodiment. Fig. 5 is an enlarged view of the front view of Fig. 3. Note that in the drawings, the lighting device 1 is shown without a device housing and a board on which a light source is arranged.

[0014] Here, it is assumed that the lighting device 1 is disposed in the passenger compartment of an automobile. The automobile is assumed to be a right-hand drive vehicle with the driver's seat on the right side and the passenger seat on the left side facing the traveling direction of the automobile (positive direction of the X-axis). It is assumed that the lighting device 1 is disposed in an overhead console provided between the driver's seat and the passenger seat from the upper part of the windshield to the ceiling of the automobile, with the emission surface slightly tilted (for example, 18.5° tilted) from facing downward to the non-traveling direction (negative direction of the X-axis), but the posture during use is not limited to this. The light distribution of the lighting device 1 corresponds to spot lighting for illuminating the driver's seat, spot lighting for illuminating the passenger seat, and room lighting by both spot lighting, but the number and shape of the light distribution can be changed depending on the application.

[0015] 1 to 5, the lighting device 1 includes two light sources 2 (21, 22), two cup lenses 3 (31, 32), a light guide 4, two light collecting sections 5 (51, 52), four microlens arrays 6 (61, 62, 63, 64), and a suppression section 7.

[0016] When referring to light source 21 and light source 22 collectively without distinction, they are written as "light source 2 (21, 22)" or "light source 2". When referring to cup lens 31 and cup lens 32 collectively without distinction, they are written as "cup lens 3 (31, 32)" or "cup lens 3". When referring to light collecting section 51 and light collecting section 52 collectively without distinction, they are written as "light collecting section 5 (51, 52)" or "light collecting section 5". When referring to microlens array 61 and microlens array 62 collectively without distinction, they are written as "microlens array 6 (61, 62)" or "microlens array 6".

[0017] The light sources 2 (21, 22) are, for example, LEDs (Light Emitting Diodes) that emit blue light. Each light source 2 is disposed on the bottom side of each cup lens 3, where the area is small, and emits light toward each cup lens 3.

[0018] The cup lenses 3 (31, 32) have a substantially truncated cone shape and are light distribution lenses that distribute the light emitted from each light source 2. For example, one cup lens 3 is provided for each light source 2.

[0019] A concave portion is provided on the bottom side of the cup lens 3, which has a smaller area, and a convex lens portion is provided at approximately the center of the bottom of the concave portion. The convex lens portion is formed asymmetrically by a free-form surface designed to refract light so as to obtain a predetermined light distribution. In addition, the outer peripheral side surface of the cup lens 3 is a total reflection portion, which totally reflects light inside the lens. The cross-sectional shape of the total reflection portion is formed asymmetrically by a free-form surface designed to totally reflect light so as to obtain a predetermined light distribution. In other words, the cup lens 3 distributes the light emitted from each light source 2 by the functions of the concave portion, the convex lens portion, and the total reflection portion, and emits the light from the bottom surface, which has a larger area.

[0020] The light guide 4 guides the light distributed by each of the cup lenses 3. The light guide 4 is formed in a plate shape and has a top surface 4a and a bottom surface 4b opposite to the top surface 4a. The light guide 4 has the cup lenses 3 spaced apart on the top surface 4a. The top surface 4a is also called a first surface, and the bottom surface 4b is also called a second surface.

[0021] The light guide 4 also emits a portion of the light from each cup lens 3 from an emission surface including at least a portion of the surface of the bottom surface 4b facing each cup lens 3. Microlens arrays 61 and 62 are provided on the emission surface of the light guide 4. The light guide 4 also guides a portion of the light from each cup lens 3 to the light collecting section 5. The emission surface of the light guide 4 is also called a first emission surface.

[0022] Light collecting section 5 (51, 52) collects (captures) light that has been guided inside light guide 4 and emits it from the emission surface. Light collecting section 5 is provided on bottom surface 4b and has a cylindrical shape extending in a direction away from a surface portion different from the surface portion facing each cup lens 3, and an end surface of the cylindrical shape is the emission surface. Note that in the illustrated example, a case is described in which the cross section of light collecting section 5 in the XZ plane is circular, but the embodiment is not limited to this and may be any shape, such as a triangle or a rectangle.

[0023] One light collecting unit 5 is provided for each cup lens 3. The exit surface of light collecting unit 5 is, for example, a circle with a diameter of 4 mm. A microlens array 63 is provided on the exit surface of light collecting unit 51, and a microlens array 64 is provided on the exit surface of light collecting unit 52. The exit surface of light collecting unit 5 is also called the second exit surface.

[0024] The microlens array 6 (61, 62, 63, 64) has a structure in which hemispherical convex portions are densely arranged in a staggered pattern, for example. The radius of the hemispheres constituting the convex portions is, for example, 0.3 mm. The microlens array 6 has the effect of diffusing light, and therefore has the effect of eliminating color unevenness (yellow ring) of the LED of the light source 2 and the effect of widening the light distribution. The microlens array 6 may be realized by a resin having a fine rough surface or scattering particles mixed therein.

[0025] Here, the microlens array 61 diffuses and emits a portion of the light from the cup lens 31. The microlens array 62 diffuses and emits a portion of the light from the cup lens 32. The microlens array 61 and the microlens array 62 are also called first optical elements.

[0026] Furthermore, the microlens array 63 diffuses and emits light that is collected by the light collecting section 51 out of the light from the cup lens 31. The microlens array 64 diffuses and emits light that is collected by the light collecting section 52 out of the light from the cup lens 32. The microlens array 63 and the microlens array 64 are also referred to as second optical elements.

[0027] The suppression unit 7 suppresses the light from each cup lens 3 from being guided to a light collecting unit 5 other than the light collecting unit 5 provided for each cup lens 3. Specifically, the suppression unit 7 suppresses the light from the cup lens 31 from being guided to the light collecting unit 52, and suppresses the light from the cup lens 32 from being guided to the light collecting unit 51.

[0028] 5, the suppression portion 7 is, for example, five optical elements 7a, 7b, 7c, 7d, and 7e formed on the upper surface 4a of the light guide 4. Each of the five optical elements 7a, 7b, 7c, 7d, and 7e is a concave prism formed along the X-axis direction and having a triangular groove (space) in cross section in the YZ plane.

[0029] The multiple cup lenses 3, the light guide 4, the multiple light collecting sections 5, the multiple microlens arrays 6, and the suppression section 7 are integrally formed.

[0030] An example of light emission from the light source 21 in the front view of the lighting device 1 will be described with reference to Fig. 6. Fig. 6 is a diagram showing an example of light emission from the light source 21 in the front view of the lighting device 1. In Fig. 6, arrows indicate an example of a light path.

[0031] As shown by the solid arrows in Fig. 6, the light emitted from the light source 21 is distributed in the cup lens 31, and diffused by the microlens array 61 to be irradiated to the passenger seat, acting as a spotlight on the passenger seat side. Here, a part of the light that reaches the microlens array 61 is totally reflected and becomes unnecessary light. As shown by the dashed-dotted arrows in Fig. 6, the unnecessary light is guided inside the light guide 4, collected by the light collecting section 51, and emitted by the microlens array 63 to act as a symbolic light on the passenger seat side.

[0032] Here, some of the unnecessary light may not be collected by the light collecting section 51, and may leak out from the exit path to the passenger seat side. As shown by the dashed arrow in FIG. 6, the leaked light may head toward the exit path to the driver's seat side (light collecting section 52), but most of the light is reflected by the suppression section 7 to the exit path to the passenger seat side, or is emitted outside the light guide plate. The light emitted outside the light guide plate can be made invisible by covering the suppression section 7 with a part of the housing (light shielding plate). As a result, the lighting device 1 can suppress the leakage of light from the light source 21 to the light collecting section 52. The same applies to the other light source 22. That is, the lighting device 1 according to the embodiment can suppress the leakage of light between the driver's seat side and the passenger seat side. Therefore, the lighting device 1 according to the embodiment can easily determine the lighting state of each spotlight by visually checking the symbol lights on the driver's seat side and the passenger seat side, respectively.

[0033] As an example, when the passenger side spotlight is turned on, the luminous flux from the passenger side symbol light is approximately 0.15% of the light source, and the luminous flux from the driver side symbol light is approximately 0.01%, which translates to a ratio of approximately 15 times the amount of light between the lit and unlit sides. For this reason, it can be said that the lighting status of each spotlight can be easily determined by visually checking the two symbol lights.

[0034] As a comparative example, when the suppression unit 7 is not provided, the luminous flux from the symbol lighting on the driver's side due to the spotlight on the passenger side being turned on is about 0.08%, which is about 1.9 times the light amount ratio of the lit side to the non-lit side. In other words, in the comparative example, the symbol lighting on the non-lit side also emits light relatively brightly, suggesting the effectiveness of the suppression unit 7 according to the embodiment.

[0035] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0036] (Variation 1) In the above embodiment, the suppression portion 7 extends from one end to the other end of the light guide 4 in the X-axis direction, but is not limited thereto. For example, the suppression portion 7 does not necessarily have to extend from one end to the other end of the light guide.

[0037] 7 is a perspective view of the lighting device 1 according to the modified example 1, seen from the back side of the light output surface. As shown in FIG. 7, the lighting device 1 according to the modified example 1 includes a suppression unit 8 instead of the suppression unit 7 in FIG.

[0038] The suppression section 8 is shorter than the length of the light guide 4 in the X-axis direction. However, the length of the suppression section 8 is preferably longer than the length of the cup lens 3 in the X-axis direction. In other words, the length of the suppression section 8 in the extension direction is longer than the length of the cup lens 3 in the same direction. Note that the configuration of the lighting device 1 according to the first modification example, other than the length of the suppression section 8, is similar to the configuration of the lighting device 1 shown in the above embodiment.

[0039] (Variation 2) In the above embodiment, the suppression unit 7 is configured by a concave prism, but the present invention is not limited to this. For example, the suppression unit 7 may be configured by a convex prism.

[0040] 8 is an enlarged front view of the lighting device 1 according to the modified example 2. As shown in FIG. 8, the lighting device 1 according to the modified example 2 includes a suppression unit 10 instead of the suppression unit 7 in FIG.

[0041] 8, the suppression unit 10 is, for example, five optical elements 10a, 10b, 10c, 10d, and 10e formed on the upper surface 4a of the light guide 4. Each of the five optical elements 10a, 10b, 10c, 10d, and 10e is a convex prism that extends along the X-axis direction and has a triangular cross section in the YZ plane. Note that in the illumination device 1 according to the second modification, the configuration other than the shape of the suppression unit 10 is similar to the configuration of the illumination device 1 shown in the above embodiment.

[0042] (Variation 3) In the above embodiment, the suppression portion 7 is formed on the upper surface 4a of the light guide 4, but this is not limiting. For example, the suppression portion 7 may be formed on the bottom surface 4b of the light guide 4.

[0043] 9 is an enlarged front view of the lighting device 1 according to the modified example 3. As shown in FIG. 9, the lighting device 1 according to the modified example 3 includes a suppression unit 11 instead of the suppression unit 7 in FIG.

[0044] 9, the suppression section 11 is, for example, five optical elements 11a, 11b, 11c, 11d, and 11e formed on the bottom surface 4b of the light guide 4. Each of the five optical elements 11a, 11b, 11c, 11d, and 11e is a concave prism that extends along the X-axis direction and forms a groove (space) whose cross section in the YZ plane is triangular. Note that in the illumination device 1 according to the third modification, the configuration other than the shape of the suppression section 11 is the same as the configuration of the illumination device 1 shown in the above embodiment.

[0045] The suppression portion 7 may be formed on both the upper surface 4a and the lower surface 4b of the light guide 4, rather than on just one of the upper surface 4a and the lower surface 4b.

[0046] (Variation 4) In the above embodiment, the suppression unit 7 is described as being composed of a plurality of concave prisms, but the present invention is not limited to this. For example, the suppression unit 7 may be composed of a plurality of holes.

[0047] Fig. 10 is a perspective view of the lighting device 1 according to the modified example 4, as viewed from the back side of the light output surface. As shown in Fig. 10, the lighting device 1 according to the modified example 4 includes a suppression unit 9 instead of the suppression unit 7 in Fig. 1.

[0048] 10, the suppression portion 9 is, for example, six holes formed on the upper surface 4a of the light guide 4. The six holes extend along the X-axis direction. The six holes may or may not penetrate to the bottom surface 4b. Note that in the illumination device 1 according to the fourth modification, the configuration other than the shape of the suppression portion 9 is similar to the configuration of the illumination device 1 shown in the above embodiment.

[0049] (Variation 5) The suppression unit 7 described in the above embodiment suppresses the leakage of light between two areas on the passenger seat side and the driver seat side, but is not limited to this. For example, the suppression unit 7 can suppress the leakage of light between three or more areas.

[0050] Fig. 11 is a perspective view of the lighting device 1 according to the modified example 5, seen from the back side of the light exit surface. As shown in Fig. 11, the lighting device 1 according to the modified example 5 has a structure in which two lighting devices 1 shown in Fig. 1 are arranged in the X-axis direction, and includes a suppression unit 12 instead of the suppression unit 7 in Fig. 1.

[0051] 11, the illumination device 1 according to the fifth modification includes four light sources 2 (21, 22, 23, 24), four cup lenses 3 (31, 32, 33, 34), a light guide 4, four light collecting sections 5 (51, 52, 53, 54), eight microlens arrays 6 (61, 62, 63, 64, 65, 66, 67, 68), and a suppression section 12. For convenience, the four light collecting sections 5 (51, 52, 53, 54) and the eight microlens arrays 6 (61, 62, 63, 64, 65, 66, 67, 68) are not shown, but the basic configuration is the same as in the above embodiment.

[0052] Suppression section 12 includes optical element 12a extending in the X-axis direction and optical element 12b extending in the Y-axis direction. As a result, it is possible to suppress leakage of light from light source 21 to light collecting sections 52, 53, and 54. The same applies to the other light sources 22, 23, and 24. In other words, lighting device 1 according to the embodiment can suppress leakage of light between multiple regions.

[0053] Furthermore, the present invention is not limited to the above-mentioned embodiment. The present invention also includes a configuration in which the above-mentioned components are appropriately combined. Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the above-mentioned embodiment, and various modifications are possible. [Explanation of symbols]

[0054] 1 lighting device, 2, 21, 22, 23, 24 light source, 3, 31, 32, 33, 34 cup lens, 4 light guide, 4a upper surface, 4b bottom surface, 5, 51, 52 light collecting section, 6, 61, 62, 63, 64, 65, 66, 67, 68 microlens array, 7, 8, 9, 10, 11 suppression section, 7a, 7b, 7c, 7d, 7e, 12a, 12b optical element

Claims

1. A plurality of light sources; A plurality of light distribution lenses, each of which is provided for each light source; a light guide body in which the light distribution lenses are arranged at a distance from each other on a first surface, and a part of the light from each light distribution lens is output from a first emission surface including at least a part of a surface facing the light distribution lens among a second surface opposite to the first surface, and the light guide body guides a part of the light from each light distribution lens; a plurality of light collecting sections each provided for each light distribution lens, each collecting the light guided through the light guide body and emitting the light from a second exit surface; A lighting device comprising:

2. Further, a suppression unit is provided to suppress the light from each light distribution lens from being guided to a light collection unit other than the light collection unit provided for each light distribution lens.

10. The lighting device of claim 1.

3. The suppression portion is formed on the first surface.

3. The lighting device according to claim 2.

4. The suppression portion is formed on the second surface.

3. The lighting device according to claim 2.

5. The length of the suppression portion in the extension direction is longer than the length of the light distribution lens in the same direction.

3. The lighting device according to claim 2.

6. The suppression portion is a concave prism.

3. The lighting device according to claim 2.

7. The suppression portion is a convex prism.

3. The lighting device according to claim 2.

8. The suppression portion is a plurality of holes.

3. The lighting device according to claim 2.

9. The first exit surface has a plurality of first optical elements that diffuse and emit the light from the light distribution lens.

10. The lighting device of claim 1.

10. The second exit surface has a plurality of second optical elements that diffuse and emit the light guided within the light guide body.

10. The lighting device of claim 1.

11. The light collecting portion is provided on the second surface and has a cylindrical shape extending in a direction away from a surface different from the surface facing the light distribution lens, and an end surface of the cylindrical shape is the second emission surface.

10. The lighting device of claim 1.

12. The light distributing lens is asymmetric.

10. The lighting device of claim 1.

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