Vehicular lighting structure
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- HAYASHI TELEMPU CO LTD
- Filing Date
- 2023-07-04
- Publication Date
- 2026-06-09
AI Technical Summary
Existing lighting structures for vehicle windows, such as those described in Patent Document 1, suffer from low light emission efficiency and energy inefficiency when using light-emitting diodes or optical fibers.
A laminated glass structure with a stepped portion and integrated lighting units, including a light guide and reflective surfaces, is used to efficiently distribute light across a wide area of the window glass, enhancing luminous efficiency by guiding light from the light sources through a sealed housing.
The proposed structure allows for higher luminous efficiency and wider illumination of the window glass, utilizing at least 40% of the total luminous flux at an incident angle of 20° or less, thereby improving light utilization and protecting the light sources.
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Abstract
Description
[Technical field]
[0001] The present invention relates to a lighting structure for a vehicle, and more particularly to a lighting structure for illuminating a window glass (e.g., a roof glass) of a vehicle. [Background technology]
[0002] Various lighting structures are installed on vehicles such as automobiles for the purpose of improving practicality and / or design. A window glass (glazing) may be installed on the roof of a vehicle to be used as a sunroof. As an example, Patent Document 1 describes a light-emitting vehicle glazing that uses a light-emitting diode or an optical fiber as a light source to make the window glass of the vehicle emit light. [Prior art documents] [Patent documents]
[0003] [Patent Document 1] Patent No. 5802684 Summary of the Invention [Problem to be solved by the invention]
[0004] In Patent Document 1, light-emitting diodes or optical fibers are installed on the end face or surface of window glass (glazing) to make the window glass emit light. However, the inventors have found that such a configuration has low efficiency in using light emitted from the light source, and low energy efficiency for lighting effects. In view of the above circumstances, the present invention aims to provide an illumination structure that efficiently uses emitted light and can make the window glass emit light over a wide range. [Means for solving the problem]
[0005] A first aspect of the present invention is a lighting structure for a vehicle that illuminates a window glass of the vehicle, A window pane and at least one lighting unit, the window glass is a laminated glass in which a first glass plate, an interlayer film, and a second glass plate are laminated in this order; The window glass has a main body having a laminated glass structure and a step portion including only the first glass plate out of the first glass plate and the second glass plate when viewed in a thickness direction, the lighting unit includes a plurality of light sources, a support body for supporting the light sources, and a light guide for guiding light emitted from the light sources and causing the light to enter an end surface of the second glass plate at a boundary between the main body and the step portion; This is a lighting structure in which the light guide comprises a storage section that stores the light source and has a light receiving surface that receives light emitted from the light source, a light emitting surface that is opposed to the end face of the second glass plate at the boundary between the main body and the step section, and a light guide section that is arranged between the light receiving surface and the light emitting surface and guides the light received at the light receiving surface to a position away from the light source in the thickness direction of the window glass, and the light source is sealed between the light guide and the support body.
[0006] According to the lighting structure having the above configuration, the light emitted from the multiple light sources is introduced through the light guide, so that the window glass (e.g., roof glass) can be efficiently illuminated. In this case, by appropriately designing the shape of the light guide portion, the light emitted from the multiple light sources can be mixed to increase the luminous efficiency, and the light source can be protected by the sealed structure.
[0007] In the above vehicle lighting structure, the light guide portion of the light guide body includes a first reflecting surface that reflects light incident on the light guide body from the light receiving surface, and a second reflecting surface that reflects the light reflected by the first reflecting surface toward the light emitting surface, The first reflection surface is a curved surface in which an angle θ1 between a surface tangent to the first reflection surface and the light-emitting surface in a cross section of the light guide decreases toward the light-emitting surface, The lighting structure may be characterized in that the second reflective surface is a curved surface in which an angle θ2 that a surface tangent to the second reflective surface makes with respect to the light-emitting surface in a cross section of the light guide increases toward the light-emitting surface.
[0008] According to the above vehicle lighting structure, light that has entered the window glass can be guided to a location away from the end face, making it possible to illuminate a wide area.
[0009] In the vehicle lighting structure, the step may be partially provided on a peripheral portion of the window glass, and the lighting unit may be at least partially housed in the step. By disposing the lighting structure on the peripheral portion of the window glass, the window glass can be made to emit light over a wide range.
[0010] The lighting structure may be such that, in a cross section perpendicular to the surface of the window glass, light that enters the window glass at an incident angle of 20° or less accounts for 40% or more of the total luminous flux of the light source 1. This can increase the light utilization efficiency. Effect of the Invention
[0011] According to the lighting structure of the present invention, it is possible to cause the window glass to emit light with higher luminous efficiency than when a light source is disposed directly on the end face of the window glass. [Brief description of the drawings]
[0012] [Figure 1] 1A is a bottom view from the rear side, and FIG. 1B is a schematic side view showing a vehicle lighting structure according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged view of a portion indicated by II in FIG. [Diagram 3] FIG. 2 is an enlarged view of a portion indicated by III in FIG. [Figure 4] 2 is a perspective view showing the configuration of each part of a lighting unit included in the lighting structure of FIG. 1. [Diagram 5] 5 is a plan view showing a state in which the lighting unit shown in FIG. 4 is assembled. [Figure 6] 5 is a front view showing a state in which the lighting unit shown in FIG. 4 is assembled. [Figure 7] 6 is a cross-sectional view of a portion shown by line VII-VII in FIG. 5. [Figure 8]8 is a cross-sectional view of a portion shown by line VIII-VIII in FIG. 5. [Figure 9] 4 is a cross-sectional view showing the cross-sectional structure of a step portion of a window glass. FIG. [Figure 10] 10 is a diagram showing the results of a simulation of the optical path of light emitted from a light source of the illumination control unit and incident on the end face of the stepped portion in FIG. 9. [Figure 11] FIG. 4 is a cross-sectional view of an end portion of the lighting unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1(A) is a bottom view of a vehicle lighting structure 1 according to an embodiment of the present invention seen from the back side, and FIG. 1(B) is a schematic side view of the same lighting structure 1. As shown in FIGS. 1(A) and 1(B), the lighting structure 1 is composed of a window glass 10 and lighting units 20 arranged in step portions (cutout portions) 10b partially provided in a peripheral portion 10a of the window glass 10. In the embodiment of FIG. 1, four lighting units 20 are arranged in four step portions 10b, but the number of step portions 10b and lighting units 20 can be appropriately selected depending on the size and shape of the window glass, the design of the lighting, and the like. In addition, in order to make the window glass 10 emit light effectively, a known scattering layer (not shown) may be provided on the window glass 10.
[0014] Fig. 2 is an enlarged view of the part indicated by II in Fig. 1(A), and Fig. 3 is an enlarged view of the part indicated by III in Fig. 1(B). The main body 10c of the window glass 10 has a laminated glass structure consisting of a first glass sheet (outer glass sheet) 11, a second glass sheet (inner glass sheet) 12, and an intermediate film 13, and in a part of the peripheral portion 10a, the second glass sheet 12 and the intermediate film 13 are cut out to provide a step portion 10b including only the first glass sheet. The lighting unit 20 is disposed in the step portion 10b and fixed to the first glass sheet 11, and is connected to a power source (not shown) via a harness 21.
[0015] 4 is a perspective view showing the components of the lighting unit 20. The lighting unit 20 is connected to a harness 21 via a power socket 22 and includes a support (LED board) 24 supporting a plurality of light sources 23 (10 in the illustrated example) made of LEDs, a light guide 25 arranged on the support 24, and a case member 26 housing the support 24. The support 24 is fixed to the light guide 25 by a screw 27, and the case member 26 is also fitted to the light guide 25. The lighting unit 20 is fixed to the window glass 10 via a double-sided adhesive tape 29 attached to an upper surface 25a of the light guide. The case member 26 is provided with an opening 26a for ventilation, and the opening 26a is sealed with a breathable film 28 having waterproof properties.
[0016] Fig. 5 is a plan view of the assembled lighting unit, and Fig. 6 is a front view. Fig. 7 is a cross-sectional view of the portion indicated by VII-VII in Fig. 5, and Fig. 8 is a cross-sectional view of the portion indicated by VIII-VIII in Fig. 5. The length D (the dimension along the edge 10a of the window glass 10 in Fig. 1) and width W of the lighting unit 20 shown in Fig. 5 are set according to the number of light sources 23 to be mounted. 8, the light guide 25 includes a storage section 25c that stores the light source 23 and has a light-receiving surface 25b that receives light emitted from the light source 23, a light-emitting surface 25d that is opposed to an end face (10d in FIG. 10) of the window glass main body 10c that faces the step portion 10b, and a light guide section 25e that is disposed between the light-receiving surface 25b and the light-emitting surface 25d and guides the light received by the light-receiving surface 25b to a position separated from the light source in the thickness direction of the window glass, and the light source 23 is sealed between the light guide 25 and the support body 24. The light-receiving surface 25b, the light guide section 25e, and the light-emitting surface 25d may hereinafter be referred to as a lens section 25f.
[0017] FIG. 9 is a diagram showing a cross-sectional structure of the window glass 10 near the step portion 10b. Laminated glass for automobiles usually has a structure in which a first glass sheet (outer glass sheet) 11 and a second glass sheet (inner glass sheet) 12 made of a highly transparent material such as soda glass sandwich an intermediate film 13 made of polyvinyl butyral (PVB) or the like. In the present embodiment, the main body 10c of the window glass 10 also has a laminated glass structure, but the second glass sheet 12 and the intermediate film 13 are cut out in a part of the peripheral portion 10a of the window glass 10 to form the step portion 10b. Only the first glass sheet 11 is present in the step portion 10b, and the lighting unit 20 is at least partially housed in a space (step portion space) 14 surrounded by the surface 11a of the first glass sheet 11 and the edge surface 10d of the window glass 10 at the boundary between the step portion 10b and the main body 10c, i.e., the edge surface 13a of the intermediate film 13 and the edge surface 12a of the second glass sheet 12. In order to use the window glass 10 as an illumination body, it is necessary to guide the light L1 incident on the second glass plate 12 while reflecting it at the surface 12b of the second glass plate 12 and the interface 12c between the second glass plate 12 and the intermediate film 13. As a result of the inventors' study of the optical structure, it was found that in order to guide the light as described above, the incident angle θ of the light incident on the window glass 10 should be adjusted to preferably 30 degrees or less, more preferably 20 degrees or less, in a cross section perpendicular to the surface 12b of the second glass plate 12 and the end face 10d of the window glass 10 facing the step portion 10b. When the incident angle θ is set to a high angle, the incident light L2 enters the intermediate film 13 and is scattered by transmitting through the first glass plate depending on the angle, or even if the incident light L3 is reflected at the interface 13a between the intermediate film 13 and the first glass plate 11, a proportion of the light is absorbed by the intermediate film 13. Therefore, an optical structure in which as much of the light flux emitted from the light source as possible has an incident angle of 20 degrees or less was studied.
[0018] 10 is a diagram showing the results of simulating the optical path of light emitted from a light source, incident on lens portion 25f of light guide 25, guided thereto, and incident on window glass 10. Light incident from light receiving surface 25b of light guide 25 is first reflected by lower surface (first reflecting surface) 25g of light guide portion 25e, and then reflected once or twice by upper surface (second reflecting surface) 25h of light guide portion 25e, and then incident on end surface 10c of window glass 10 facing step portion 10b, i.e., end surface 12a of the second glass plate or end surface 13a of the intermediate film. When viewed from the contour of the cross-sectional structure, light receiving surface 25b and light emitting surface 25d are parallel to each other and straight, while first reflecting surface 25g is a downwardly convex curve, and second reflecting surface 25h is an upwardly convex curve. However, the angle between the tangent of the first reflecting surface 25g and the light emitting surface 25d, and the angle between the second reflecting surface 25h and the light emitting surface 25d are both 90 degrees or less.
[0019] In other words, the first reflective surface 25g is a curved surface in which the angle θ1 that a surface tangent to the first reflective surface 25g makes with respect to the light-emitting surface 25d on the cross section of the light guide 25 becomes smaller toward the light-emitting surface 25d, and the second reflective surface 25h is a curved surface in which the angle θ2 that a surface tangent to the second reflective surface 25h makes with respect to the light-emitting surface 25d on the cross section of the light guide 25 becomes larger toward the light-emitting surface 25d.
[0020] In the light guide 25 in which the lens portion 25f has the above-mentioned shape, a shape that further enhances the light emission efficiency of the window glass 10 was studied. FIG. 11 is a diagram showing a cross-sectional structure of the end portion of the light-emitting unit 20, and shows a cross section perpendicular to the light-emitting surface 25d of the light guide 25 and the upper surface 25a of the storage portion 25c. In the cross section, the distance T1 between the lowermost part of the upper surface of the light guide portion 25e of the light guide 25 and the first reflecting surface 25g is preferably smaller than the distance T2 between the uppermost part of the lower surface of the light guide portion 25e and the uppermost part of the second reflecting surface 25h, and the curvature radius R1 of the first reflecting surface 25g is preferably smaller than the curvature radius R2 of the second reflecting surface 25h. For example, T1 / T2 may be 0.5 to 1, preferably 0.7 to 0.9, and R1 / R2 may be 0.1 to 1.0, preferably 0.3 to 0.8. In the configuration shown in FIG. 11, it is preferable that the width of light-guiding section 25e, i.e., the shortest distance w from light-receiving surface 25b to light-emitting surface 25d, is 3.0 to 15.0 mm, the radius of curvature R1 is 1.0 to 8.0 mm, the radius of curvature R2 is 2.0 to 10.0 mm, T1 is 1.0 to 5.0 mm, and T2 is approximately 1.0 to 5.0 mm.
[0021] With the above configuration, light that enters the window glass at an incident angle θ of 20° or less in a cross section perpendicular to the surface of the window glass 10 in FIG. 9 can account for 40% or more of the total luminous flux of the light source (LED).
[0022] In the vehicle lighting structure 1 having the above configuration, a normal LED can be used as the light source. The color of the LED light is not particularly limited, and a single-color LED of red, blue, or green, a white LED, or a full-color LED can be used. A normal glass epoxy board (FR4) with wiring for LED light emission can be used as the support (LED board). The case member can be made of engineering plastics such as polycarbonate and ABS resin. An acrylic resin such as PMMA can be used as the light guide.
[0023] The first glass plate 11 and the second glass plate 12 constituting the window glass 10 may be inorganic glass or organic glass. As inorganic glass, for example, soda lime glass, aluminosilicate glass, borosilicate glass, alkali-free glass, quartz glass, etc. may be used. As organic glass, polycarbonate glass, acrylic glass, etc. may be used. As the intermediate film 13, thermoplastic polyvinyl butyral (PVB), ethylene vinyl acetate copolymer (EVA), etc. may be used.
[0024] The window glass 10 may be flat, or may be curved to be slightly convex toward the vehicle interior. The second glass plate 12 and the first glass plate 11 may each have a thickness of about 1.0 to 6.0 mm, and the interlayer film 13 may have a thickness of about 0.1 to 1.2 mm. An optical pattern may be provided at the interface between the interlayer film 13 and the second glass plate 12. For example, the interlayer film 13 may have a two-layer structure, with the optical pattern provided on one of the layers.
[0025] 5 is not particularly limited in size and shape, but from the viewpoint of effective use of the window glass, the width W from the edge of the window glass to the inside is preferably about 5 mm to 20 mm. From the viewpoint of light emission efficiency, the light guide 25 of the light emitting unit 20 preferably has a curved surface that is convex toward the inside of the window glass in a plan view. Each light emitting unit may have about 1 to 30 LEDs installed at intervals of about 1.5 mm to 50 mm. The lighting structure of the present invention can be used, for example, in the roof glass of an automobile. The vehicle in which the lighting structure is used is not limited to a four-wheeled vehicle, and the lighting structure can also be used in the window glass of a railway vehicle. EXAMPLES
[0026] In order to verify the effect of the present invention, a lighting structure as shown in Fig. 1 was created. The window glass used was a 1500mm x 1000mm, 2mm-thick soda lime glass sandwiched between an interlayer. The interlayer had a two-layer structure of 0.8mm-thick polyvinyl butyral and 0.025mm-thick patterned polyvinyl butyral, the latter of which had circular scattering patterns with a diameter of 3mm at 20mm intervals as a scattering layer. At four locations on the long edge of the window glass, the second glass plate and the interlayer were cut out in an approximately arc shape, and a light-emitting unit with 10 full-color LEDs was installed in each cutout, measuring 158.3mm in width and 18.5mm in depth in the longitudinal direction.
[0027] Using the above prototype, the light emission state of red, green, and blue light was investigated at a current of 20 mA. The light emission luminance versus distance from the window glass edge 10a (see FIG. 1) was as shown in the table below. For red light, the light emission attenuated at a distance of more than 300 mm from the window glass edge 10a, but for green and blue light, a light emission state in which the luminance could be measured was observed even at a location about 500 mm from the window glass edge 10a. It was observed that the configuration of the present invention can cause almost the entire surface of the window glass to emit light. It was also confirmed that by using a mixture of red light, green light, and / or blue light, it is possible to produce a change in color tone by taking advantage of the difference in the attenuation of light emission luminance depending on the wavelength. The light emission luminance was measured using a spectrophotometer (CS-2000 manufactured by Konica Minolta).
[0028] [Table 1] [Explanation of symbols]
[0029] 1 Vehicle lighting structure 10. Window Glass 10a Periphery 10b Step 10c Main unit 10d end face 11 First glass plate 12 Second Glass Pane 13 Interlayer 20 Lighting Unit 21 Harness 22 Power socket 23 Light source (LED) 24 Support (LED board) 25 Light guide 25a Top side 25b Photosensitive surface 25c Storage section 25d Light-emitting surface 25e Light guide 25g First reflective surface 25h Second reflective surface 26 Case material 27 Screw 28 Film 29 Adhesive Tape
Claims
1. A lighting structure for a vehicle that illuminates a window glass of the vehicle, A window pane and at least one lighting unit, the window glass is a laminated glass in which a first glass plate, an interlayer film, and a second glass plate are laminated in this order; The window glass has a main body having a laminated glass structure and a step portion including only the first glass plate out of the first glass plate and the second glass plate when viewed in a thickness direction, the lighting unit includes a plurality of light sources, a support body for supporting the light sources, and a light guide for guiding light emitted from the light sources and causing the light to enter an end face of the second glass plate at a boundary between the main body and the step portion; an illumination structure in which the light guide comprises a storage section that stores the light source and has a light receiving surface that receives light emitted from the light source, a light emitting surface that is opposed to an end face of the second glass plate at the boundary between the main body and the step section, and a light guide section that is arranged between the light receiving surface and the light emitting surface and guides the light received at the light receiving surface to a position separated from the light source in the thickness direction of the window glass, and the light source is sealed between the light guide and the support.
2. 2. The lighting structure according to claim 1, wherein the light guide portion of the light guide body includes a first reflecting surface that reflects light incident on the light guide body from the light receiving surface, and a second reflecting surface that reflects the light reflected by the first reflecting surface toward the light emitting surface, The first reflection surface is a curved surface in which an angle θ1 between a surface tangent to the first reflection surface and the light-emitting surface in a cross section of the light guide becomes smaller toward the light-emitting surface, The second reflective surface is a curved surface in which an angle θ2 between a surface tangent to the second reflective surface and the light-emitting surface in a cross section of the light guide increases toward the light-emitting surface.
3. 3. The lighting arrangement according to claim 1, The step portion is partially provided on a peripheral portion of the window glass, The lighting unit is at least partially housed in the stepped portion.
4. 3. The lighting structure according to claim 1, wherein in a cross section perpendicular to a surface of the window glass, light that enters the window glass at an angle of incidence of 20° or less accounts for 40% or more of a total luminous flux of the light source.