Illumination device

Abstract

The present invention provides an illumination device which makes it possible to obtain a metallic tone or rainbow colors by means of the shape of a translucent member, the entirety of which is not monotonous, which has a good appearance, and which is rich in color variation.　Provided is an illumination device comprising a light source part and a translucent member which allows light from the light source part to pass therethrough from the back surface side to a design surface or a front surface, wherein: the translucent member has a base part which is substantially plate-shaped, a projecting part which is integrated with the base part and which projects toward the opposite side of the light source part, and a fine uneven part which is provided on the back surface of the base part facing the light source part and which produces brilliance in a metallic tone or rainbow colors by reflecting external light that is in a prescribed direction and that has entered from the projecting end surface side of the projecting part and reached the projecting part, and causing the external light to exit from the projecting end surface; and an end part of the projecting end surface of the projecting part is formed in the shape of a curved surface or an inclined surface.

Description

lighting equipment

[0001] To provide an illumination device in which light from a light source (including a light guide) is emitted from the front surface, which is a design surface, through a light-transmitting member, and which has a good appearance without monotony as a whole, and is rich in color variation, particularly when viewed from the design surface or the front surface.

[0002] 9A and 9B show an in-vehicle lighting device disclosed in Patent Document 1 below, which is capable of simultaneously illuminating multiple areas with multiple light beams using a single lighting device. Specifically, the lighting device 5 includes a light source 50 and an optical unit 6. The light source 50 is an LED, and light from the LED is emitted from the front surface, which is the design surface, toward the optical unit 6. The optical unit 6 includes a prism array 61 provided on the incident side and a first lens unit 64 and a second lens unit 65 provided on the exit side. The prism array 61 refracts light emitted from the light source 50 and generates a first divided beam 52 and a second divided beam 53 by causing them to intersect with each other. The first divided beam 52 is emitted from the first lens unit 64 to illuminate the USB socket 10, which is a first area. The second divided beam 53 is emitted from the second lens unit 65 to illuminate the bottom surface 22 of the storage compartment 21, which is a second area. Furthermore, in this lighting device 5, the curvature of the first lens portion 64 is formed to be greater than the curvature of the second lens portion 65, so that the light emitted from the first lens portion 64 can illuminate a narrower range than the light emitted from the second lens portion 65.

[0003] 10A and 10B show a light-transmitting member disclosed in Patent Document 2, in particular, by providing a prism portion that is shiny (plated or exhibits metallic or iridescent colors), the shape of the light-transmitting member alone provides a shiny appearance without the need for decoration with a metallized film or the formation of a non-metallic paint layer or metal layer. That is, the light-transmitting member 20 is attached to the recess 11 of the housing 10 so that its surface is exposed from the recess. The prism portion 22 reflects light incident from the front of the light-transmitting member 20 in a predetermined direction toward the front and emits it from the front, thereby producing a metallic or iridescent shine. The prism portion 22 is formed on the bottom surface of the recess 21 provided on the back surface of the light-transmitting member 20, or the like, and has a substantially triangular cross section. The prism portion 22 is a fine irregularity formed by repeatedly arranging a plurality of protrusions 23, each of which has a reclined triangular prism shape. The prism portion 22 totally reflects external light from a predetermined direction and emits it from the front, producing a metallic or iridescent shine.

[0004] Patent No. 6806358 Patent No. 5202602

[0005] The lighting device of Patent Document 1 refracts light from a light source to emit a first split beam and a second split beam, and is capable of irradiating a first region, which is a distant location, with the first split beam and irradiating a second region with the second split beam. This eliminates the need to provide different light sources for different regions, thereby reducing the number of components. However, this lighting device is unable to produce a metallic or rainbow-colored glow when viewed from the front, as in Patent Document 2. Furthermore, Patent Document 2 discloses a technology for producing a metallic or rainbow-colored effect, but the overall metallic effect is monotonous.

[0006] Therefore, an object of the present invention is to provide a lighting device that can achieve metallic or rainbow colors in the form of a light-transmitting member, and also to provide a lighting device that is not monotonous but has a good appearance, and is particularly rich in color variation and originality. Other objects will become clear in the following description.

[0007] In order to achieve the above object, the present invention provides an illumination device comprising a light source unit and a translucent member that allows light from the light source unit to pass from the back side to the design surface or the front side, wherein the translucent member has a substantially plate-shaped base, a protruding portion that is integrated with the base and protrudes on the side opposite the light source unit, and a fine uneven portion that is provided on the back side of the base facing the light source unit and that reflects external light that enters and reaches from the protruding end face side of the protruding portion in a predetermined direction and emits it from the protruding end face, thereby allowing the light to shine in a metallic or rainbow color, and further characterized in that the end of the protruding end face of the protruding portion is formed into a curved surface or an inclined surface.

[0008] In the present invention, the light-transmitting member is a member such as a natural glass, such as silicate glass or silica glass, or a resin glass, such as an acrylic or polycarbonate, that transmits light, and is not limited to being colorless and transparent, but may be colored and transparent. The external light is sunlight or light from various lamps or light sources installed inside a room or a vehicle cabin.

[0009] Furthermore, the present invention is more preferably embodied as follows: (1) The light source section is a light guide that introduces light from a light source. (2) The fine irregularities are formed over a relatively wider area than the protruding end faces of the protrusions. (3) The light guide has an area equal to or larger than the area of ​​the fine irregularities.

[0010] (4) The fine concave-convex portion is an arrangement of a plurality of convex portions or concave portions, and the pitch L is 0.5 μm or more and 500 μm or less. (5) The lighting device has a configuration including a housing having a accommodating groove in which the light guide can be positioned and disposed, a concave portion in which the light source can be positioned and disposed on one end side of the accommodating groove, and a step in which the light-transmitting member can be positioned and disposed on a groove edge side of the accommodating groove.

[0011] According to the present invention, the protruding portion of the light-transmitting member totally reflects external light incident from the front side by the fine irregularities provided on the back surface of the base, and light from the light source (light guide) is refracted into the light-transmitting member by the fine irregularities. Therefore, the light from the light source is less likely to be emitted toward the front (it is weak), and the reflected external light appears metallic or iridescent, i.e., plated, when viewed from the front. Furthermore, external light is refracted and incident at the end of the protruding end surface of the protruding portion, i.e., a curved or inclined surface of a predetermined size. Therefore, less external light is reflected by the fine irregularities, making the light from the light source (light guide) more visible, and the end of the protruding end surface appears brightest. In other words, in the lighting device of the present invention, the protruding end surface of the protruding portion of the light-transmitting member appears metallic or iridescent, i.e., plated, and the end of the protruding end surface of the protruding portion, i.e., a curved or inclined surface of a predetermined size, appears brightest when exposed to light from the light source (light guide). Therefore, the lighting device according to the present invention has a beautiful appearance and a richly innovative color scheme.

[0012] When the lighting device according to the present invention is configured as described in (1) above, for example, even if the fine irregularities of the light-transmitting member are formed over a wide range, it becomes easy to irradiate the entire area with light.

[0013] When the lighting device according to the present invention is configured as described in (2) above, the end of the protruding end face of the protruding portion appears brighter than other portions.

[0014] When the lighting device according to the present invention is configured as described in (3) above, it becomes easy to manufacture because there is no need to strictly control the processing range of the fine concave and convex portions.

[0015] When the lighting device according to the present invention is configured as described in (4) above, the totally reflected emitted light can reliably shine metallic or rainbow-colored.

[0016] When the lighting device according to the present invention is configured as described in (5) above, the light guide, the light source, and the light-transmitting member are positioned with high precision, and the lighting device is easy to manufacture.

[0017] Figures 1A and 1B are perspective views showing a lighting device according to the present invention incorporated into a vehicle interior panel, and an exploded view showing the lighting device removed from the vehicle interior panel. Figures 2A to 2C are a front view of the vehicle interior panel, an enlarged cross-sectional view taken along line IIB-IIB in Figure 2A, and an enlarged cross-sectional view taken along line IIC-IIC in Figure 2A. Figures 3A to 3C are enlarged schematic cross-sectional views showing only the lighting device in the embodiment of Figure 2C, an enlarged view of part C in Figure 3A, and an enlarged view of part D in Figure 3B. Figure 4 is an exploded perspective view of the lighting device. Figures 5A to 5C are a front view of the lighting device, a cross-sectional view taken along line VB-VB in Figure 5A, and an enlarged cross-sectional view taken along line VC-VC in Figure 5A. Figures 6A to 6C are front, back, and top views of a single light-transmitting member constituting the lighting device. Figures 7A and 7B illustrate the principle of the above-described lighting device. Figure 7A shows a state in which external light incident from the front side is totally reflected by the fine unevenness portion and exits from the surface when the light guide is not irradiated with light. Figure 7B shows a state in which the light from the light guide is further refracted by the fine unevenness portion into the light-transmitting member and enters the light guide, causing the end of the protruding end face of the protrusion to appear brightest. Figures 8A and 8B show Variation 1 corresponding to Figure 3B and Variation 2 corresponding to Figure 3C. Figures 9A and 9B show a conventional lighting device disclosed in Japanese Patent No. 6,806,358. Figures 9A and 9B show Figure 2 and Figure 3 of the same publication. Figures 10A and 10B show a conventional configuration disclosed in Japanese Patent No. 5,202,602, in which a light-transmitting member appears plated (metallic or iridescent) when exposed to external light. Figures 10A and 10B show Figure 2 and Figure 10B show Figure 4 of the same publication.

[0018] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In this description, the structure of the lighting device shown in Figures 1A to 6C will first be described. Next, main operational features will be clarified with reference to Figures 7A and 7B. After that, reference will be made to modified examples shown in Figures 8A and 8B. Note that hatching of the light-transmitting member and light guide body has been omitted in Figures 3A to 3C, Figures 7A to 7C, and Figures 8A and 8B to avoid cluttering the drawings.

[0019] (Device Structure) As is clear from the drawings, the lighting device 2 of the preferred embodiment of the present invention has a structure in which a light-transmitting member 3 that transmits light and a light guide 4 into which light from a light source such as an LED 28 is incident are incorporated into a housing 20. Here, as shown in Figures 4 and 5A and 5B, the housing 20 integrally comprises a horizontal groove-like accommodation groove 21 that is elongated from side to side and capable of positioning the light guide 4, a recess 22 provided at one end of the accommodation groove 21 and capable of positioning the LED 28 that is the light source, a step 23 that has an L-shaped cross section at the edge of the accommodation groove 21 and can position the light-transmitting member 3, and multiple fixing portions 24 provided on the upper and lower portions. The step 23 has multiple claws 23a provided on the upper and lower portions and multiple protrusions 26 provided on the recess 25 side.

[0020] The right end of the accommodation groove 21 is continuous with a recess 25 formed one level deeper, and has a roughly U-shaped arrangement section 22 adjacent to the recess 25 in which an LED 28, a light-emitting diode serving as a light source, is disposed. The LED 28 is received in the roughly U-shape of the arrangement section 22 from the opening side. The LED 28 is then positioned with its light-emitting section 29, which emits light, fitted into a window 27 provided in the roughly U-shaped partition wall, in contact with the end surface of one end 41, which is the light-introducing end of the light guide 4.

[0021] The light guide 4 comprises a long, narrow, plate-like main body 40 and one end 41 connected to one end of the main body 40 and fitted into the recess 25. The light guide 4 is assembled into the accommodation groove 21 and the recess 25 with the other end 42 abutting the left inner end surface of the accommodation groove 21 and the one end 41 abutting the window 27. In this assembled state, the light guide 4 is positioned with the upper and lower end surfaces and both end surfaces 41, 42 abutting the corresponding partition walls of the accommodation groove 21 and the recess 25. In this structure, light emitted from the light-emitting surface of the LED 28 is introduced from the one end 41 of the light guide 4, which is the light introduction end, to the other end 42 and is irradiated toward the front of the light guide 4 corresponding to the U-shaped opening of the housing 4. In this configuration, the size of the light guide 4 is set so that the irradiation range is equal to or wider than the range of the fine unevenness 38 of the light-transmitting member 3, which will be described later.

[0022] The material of the light guide 4 is not particularly limited, but for example, thermoplastic resins such as acrylic, polycarbonate, and polyolefin polymers such as cycloolefin polymer (COP), which has excellent heat resistance, high transparency, and optical properties, or similar resins are preferred. Also, in Figure 4, reference numeral 43 denotes pressure-welding portions provided on the upper and lower surfaces of one end 41 and press-bonded to the corresponding surfaces of the recess 25.

[0023] On the other hand, as shown in Fig. 4 and Figs. 6A to 6C, the light-transmitting member 3 comprises a base 30 in the shape of an elongated rectangular plate and a protrusion 35 protruding from the front side of the base 30. The base 30 is sized to fit into the step 23 of the housing and has recesses 34 that fit with the tabs 23a on the step side and slits 33 that fit with the protrusions 26 on the step side. The light-transmitting member 3 is placed on the step 30 and assembled by fitting the tabs 23a into the recesses 34 and the protrusions 26 into the slits 33. In this state, as shown in Figs. 7A and 7B, the light-transmitting member 3 is disposed between the light-transmitting member 3 and the light guide 4 via a gap S, i.e., an air layer. This is because, due to the air layer, i.e., the gap S, the refractive index of the light-transmitting member is greater than the refractive index on the light-entering side from the light guide, as shown in Fig. 7B, regardless of the materials of the light-transmitting member and the light guide, and total reflection does not occur. Therefore, the light emitted from the light guide passes through the light-transmitting member while being refracted.

[0024] As shown in FIG. 6B , a large number of fine irregularities 38 are provided at predetermined intervals on the back surface of the base 30. The fine irregularities 38 are provided on the bottom surfaces of depressions 39 provided at predetermined intervals, and as shown in FIGS. 7A and 7B , each has a substantially triangular cross section, with many of these arranged side by side. In other words, the fine irregularities 38 are similar to the prism portion of Patent Document 2, and are configured to totally reflect external light from a predetermined direction and emit it from the front, thereby creating a metallic or rainbow-like lustre similar to plating. In other words, the fine irregularities 38 are formed by repeatedly arranging protrusions or recesses, with each protrusion forming a triangle with a base of approximately 10 to 50 μm and a height of approximately 25 to 50 μm. In various prototype tests, it was found that it is preferable to arrange the convex or concave portions as the fine uneven portion 38 repeatedly at a pitch of 0.5 μm or more and 500 μm or less, or to form the fine uneven portion 38 over a range wider than the protruding end face of the protrusion 35 described below.

[0025] A protrusion 35 is integrally formed on the front surface of the base 30. The protrusion 35 is arranged to fit inside a number of fine concave-convex portions 38. Of the protrusion end surface, the upper and lower ends are formed as curved surfaces 36, and the left and right ends 37 are formed as inclined surfaces. In other words, of the protrusion end surface, which is the front or design surface of the protrusion 35, the end of the protrusion end surface is formed as the curved surface 36. This configuration allows the curved surface 36 forming the end of the protrusion end surface to shine most brightly with light from the light guide 4, as will be described later. Note that the curved surface 36 as described above may be in a form that is greatly curved from the protrusion end surface of the protrusion 35 to the upper surface of the base 30.

[0026] In the above-described lighting device 2, the light guide 4 is positioned in the accommodation groove 21, the LED 28, which is a light source that introduces light into the light guide 4, is positioned in the recess 22, and the light-transmitting member 3 is positioned in the step 23. Therefore, the light guide 4, the LED 28, and the light-transmitting member 3 can be accurately and easily assembled into the housing 2 to produce a finished product. In this embodiment, as shown in FIGS. 1A and 1B , the lighting device 2 is attached to a predetermined location constituting the instrument panel 1. That is, in this example, a window 14 is provided between the upper portion 12 and the lower portion 13 constituting the instrument panel 1, and the lighting device 2 is secured to the panel 1 from the back side of the window 14 with the protrusions 35 of the light-transmitting member inserted into the left and right groove-shaped window portions 14, using a means such as a screw.

[0027] (Operation) Figures 7A and 7B are schematic diagrams illustrating the operation of the above-described lighting device. First, Figure 7A illustrates a state in which external light, such as sunlight or indoor light, is incident on the protruding end surface of the protruding portion of the transparent member. In this state, the external light that enters from the front side and reaches the protruding portion 35 of the light-transmitting member is totally reflected by the fine irregularities 38 provided on the back surface of the base 30. Furthermore, the external light is refracted and incident on the end of the protruding end surface of the protruding portion 35, i.e., the curved surface 36 of a predetermined size. Therefore, little external light is reflected by the fine irregularities 38, and the light is refracted by the fine irregularities 38 and exits toward the light guide 4. Then, as shown in Figure 7B, when the light guide 4 is illuminated by the LED 28, the light from the light guide 4 is refracted by the fine irregularities 38 and enters the light-transmitting member 3. Therefore, the light from the light guide 4 is difficult to emit (weak light) from the front of the protrusion 35, and when viewed from the front, it appears metallic or rainbow-colored, i.e., plated, like reflected light from outside. Also, as described above, on the curved surface 36 around the protrusion 35, outside light is refracted and incident, and reflection at the fine unevenness 38 is reduced, so that the light from the light guide 4 becomes easier to see, and the curved surface portion appears the brightest.

[0028] In addition, in this lighting device 2, when the light guide 4 is not lit, the color is metallic or rainbow-colored, i.e., plated, but when the light guide 4 is lit, the curved surface 36 around the protrusion 35 shines most brightly, giving the appearance of an edge light, and a unique illumination effect in which the light gradually changes as the line of sight moves.

[0029] Another structural feature is that by using the light guide 4 as the light source, which transmits light from a light source such as an LED 28, it is possible to reliably irradiate the entire fine unevenness 38, even in an embodiment in which the fine unevenness 38 of the light-transmitting member 3 is formed over a wide area. Furthermore, the fine unevenness 38 on the back surface of the base 30 is formed over a wider area than the protruding end surface of the protruding portion 35 of the light-transmitting member 3, so that the curved surface 36 at the end of the protruding end surface glows more brightly than other areas. Furthermore, because the light guide 4 is the same size as or larger than the area of ​​the fine unevenness 38, there is no need to strictly control the processing area of ​​the fine unevenness 38, making manufacturing easier. Meanwhile, the housing 2 includes the receiving groove 21 for positioning the light guide 4, the recess 22 for positioning the LED 28, which is the light source, on one end of the receiving groove 21, and the step 23 for positioning the light-transmitting member 3 on the groove edge side of the receiving groove 21, allowing the light guide 4, the LED 28, and the light-transmitting member 3 to be accurately and easily assembled.

[0030] Furthermore, the fine irregularities 38 provided on the light-transmitting member 3 are an array of multiple convex or concave portions, and when the pitch is 0.5 μm or more and 500 μm or less, the above-mentioned totally reflected emitted light can shine with a metallic or rainbow color. However, when the pitch is less than 0.5 μm, it becomes difficult to manufacture the fine irregularities 38, and when it is greater than 500 μm, the irregular shape appears to float.

[0031] (Variation 1) Fig. 8A shows Variation 1 corresponding to Fig. 3B. In this variation, the end of the protruding end face of the protruding portion 35 of the light-transmitting member 3 is formed as an inclined surface 37 of a predetermined size instead of the curved surface 36. In the present invention, even with such an inclined surface 37, as with the curved surface 36, external light is refracted and incident at the end around the protruding portion 35. This reduces reflection at the fine unevenness 38, making the light from the light guide 4 more visible, and the inclined surface 37 appears the brightest. Note that the inclined surface 37 may be inclined significantly from the protruding end face of the protruding portion 35 to the upper surface of the base 30.

[0032] 8B shows Modification 2 corresponding to FIG. 3C. In this modification, the light-transmitting member 3 and the light guide 4 are integrated by two-color molding, insert molding, or other joining method such as welding. This type of configuration can be adopted as long as the refractive index of the light-transmitting member 3 is greater than that of the light guide 4.

[0033] While the present invention has been described assuming that the lighting device is installed in an instrument panel, it may also be installed in various consoles, door trims, roof trims, or related locations. The light-transmitting member, light guide, and housing are changed to optimal shapes depending on the location where the lighting device is installed. While the light source unit has been described using an example of a light source and a light guide, the light guide may be omitted if light can be evenly irradiated or incident on the entire light-transmitting member.

[0034] 1. Part of instrument panel (vehicle interior panel) 2. Lighting device 3. Light-transmitting member (30 is base, 35 is protrusion) 4. Light guide 20. Housing (21 is storage groove, 25 is recess, 23 is step) 28. LED (light source, 29 is emission portion) 36. Curved surface (end of protruding end face of protruding portion) 37. Inclined surface (end of protruding end face of protruding portion) 38. Fine uneven portion (L is pitch of concave or convex portions) S. Gap The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2024-17063, filed on February 7, 2024, are hereby incorporated by reference as the disclosure of the specification of the present invention.

Claims

1. A lighting device comprising a light source unit and a translucent member that allows light from the light source unit to pass from the rear side to the design surface or the front, wherein the translucent member has a substantially plate-shaped base, a protruding portion that is integrated with the base and protrudes on the side opposite the light source unit, and a fine concave-convex portion that is provided on the rear side of the base facing the light source unit and that reflects external light that has entered from the protruding end face of the protruding portion in a predetermined direction and emits it from the protruding end face, thereby allowing it to shine in a metallic or rainbow color, and further wherein the end of the protruding end face of the protruding portion is formed into a curved or inclined surface.

2. The lighting device according to claim 1, wherein the light source section is a light guide that introduces light from the light source.

3. The lighting device according to claim 1 or 2, wherein the fine irregularities are formed over a range relatively wider than the protruding end faces of the protruding portions.

4. The lighting device according to claim 2 or 3, characterized in that the light guide has an area equal to or larger than the area of the fine irregularities.

5. The lighting device according to any one of claims 1 to 4, wherein the minute concave and convex portions are an array of a plurality of convex portions or concave portions, and the pitch is 0.5 µm or more and 500 µm or less.

6. A lighting device as described in any one of claims 2 to 5, characterized in that it has a housing that forms a storage groove in which the light guide can be positioned, a recess in which the light source can be positioned on one end side of the storage groove, and a step in which the translucent member can be positioned on the groove edge side of the storage groove.

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