Lighting device

Abstract

To provide a lighting device that is capable of obtaining a metallic tone or a rainbow color in the form of a translucent member, has a good appearance without being monotonous as a whole, and is rich in color variation.SOLUTION: A lighting device 2 includes a light source unit and a translucent member 3 which can transmit light of the light source from a back-surface side to a design surface or a front surface. The translucent member 3 includes: a substantially plate-shaped base portion 30; a protruding portion 35 integrated with the base portion 30 and protruding toward a side opposite to the light source portion; and a fine uneven portion 38 provided on a back surface of the base portion 30 opposite to the light source portion, and configured to reflect external light in a predetermined direction made incident on from a protruding-end surface side of the protruding portion 35 and to emit the external light from the protruding-end surface, thereby causing the external light to shine in a metallic tone or rainbow color. In addition, an end of the protruding-end surface of the protruding portion 35 is formed into a curved surface or an inclined surface.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[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 and rich color variation, without being monotonous as a whole, particularly when viewed from the design surface or the front. [Background technology]

[0002] FIG. 9 shows an in-vehicle lighting device disclosed in Patent Document 1, specifically, a single lighting device capable of simultaneously illuminating multiple areas with multiple light beams. Specifically, the lighting device 5 includes a light source 50 and an optical unit 6. The light source 50 is an LED, and emits light from the front, 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 output side. The prism array 61 refracts the 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 the 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 the second area. Furthermore, in this lighting device 5, by forming the curvature of the first lens portion 64 to be greater than the curvature of the second lens portion 65, 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] 10 shows a light-transmitting member disclosed in Patent Document 2. In particular, the light-transmitting member includes prism portions that are shiny (plated or exhibit metallic or iridescent colors), allowing the light-transmitting member to have a shiny appearance simply through its shape, without the need for decoration with a metallized film or the formation of a non-metallic paint layer or metal layer. Specifically, 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 portions 22 reflect light incident from the front of the light-transmitting member 20 in a predetermined direction toward the front and emit it from the front, thereby creating a metallic or iridescent shine. The prism portions 22 are formed on the bottom surface of the recess 21 on the back surface of the light-transmitting member 20, or on other surfaces. The prism portions 22 have a substantially triangular cross section and are made up of a repeating array of multiple protrusions 23, each shaped like a lying triangular prism. The prism portions 22 totally reflect external light from a predetermined direction and emit it from the front, creating a metallic or iridescent shine. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6806358 [Patent Document 2] Patent No. 5202602 Summary of the Invention [Problem to be solved by the invention]

[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 can illuminate a first area, which is a distant location, with the first split beam and a second area with the second split beam, eliminating the need to provide different light sources for different areas and reducing the number of parts. However, with this lighting device, it is impossible to produce a metallic or rainbow-colored glow when viewed from the front, as in Patent Document 2. Furthermore, while Patent Document 2 uses technology to produce a metallic or rainbow-colored effect, the overall result is limited to a monotonous metallic appearance.

[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 good overall appearance without monotony, and particularly to provide color variation or originality. Other objects will become clear in the following description. [Means for solving the problem]

[0007] In order to achieve the above object, the invention of claim 1, when specified with reference to the drawings, is an illumination device 2 including a light source unit and a light-transmitting member 3 that allows light from the light source unit to pass from the back side to the design surface or the front side, wherein the light-transmitting member 3 has a substantially plate-shaped base 30, a protruding portion 35 that is integrated with the base and protrudes on the side opposite the light source unit, and a fine uneven portion 38 that is provided on the back side of the base 30 facing the light source unit and that reflects external light that has entered and reached the protruding end face side of the protruding portion in a predetermined direction and causes it to exit 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 35 is formed into a curved surface 36 or an inclined surface 37.

[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, it is more preferable that the present invention be embodied as follows. (1) The light source section is a light guide 4 that introduces light from a light source (claim 2). (2) The fine irregularities 38 are formed over a relatively wider area than the protruding end surface of the protruding portion 35 (claim 3). (3) The light guide 4 has a size equal to or larger than the area of the fine concave-convex portion 38 (claim 4).

[0010] (4) The fine concave-convex portion 38 is an array of a plurality of convex portions or concave portions, and the pitch L is 0.5 μm or more and 500 μm or less (claim 5). (5) The configuration has a housing 20 that forms a storage groove 21 in which the light guide 4 can be positioned, a recess 22 in which the light source can be positioned on one end side of the storage groove 21, and a step 23 in which the light-transmitting member 3 can be positioned on the groove edge side of the storage groove 21 (Claim 6). [Effects of the Invention]

[0011] In the invention of claim 1, the protruding portion of the light-transmitting member totally reflects external light incident from the front side due to 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, making it difficult for the light from the light source to be emitted to the front (weak light), and the reflected external light appears metallic or rainbow-colored, i.e., plated, when viewed from the front. Furthermore, at the end of the protruding end surface of the protruding portion, i.e., a curved or inclined surface of a predetermined size, external light is refracted and reflected by the fine irregularities, so less external light is reflected. This makes the light from the light source (light guide) more visible, and the end of the protruding end surface appears the 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 rainbow-colored, 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 the brightest in light from the light source (light guide), resulting in a pleasing appearance and a beautiful color scheme.

[0012] In the invention of claim 2, since the light source section is a light guide that transmits light from the light source, it is easy to irradiate the entire surface with light even if, for example, the fine unevenness of the light-transmitting member is formed over a wide range.

[0013] In the invention of claim 3, the fine irregularities are formed over a range wider than the protruding end face of the protruding portion of the translucent member, so that the end of the protruding end face of the protruding portion appears brighter than other areas.

[0014] In the invention of claim 4, the light guide has an area equal to or larger than the area of the fine concave-convex portion, so there is no need to strictly control the processing area of the fine concave-convex portion, which makes manufacturing easier.

[0015] In the invention of claim 5, when the fine unevenness is an arrangement of multiple convex or concave portions with a pitch of 0.5 μm or more and 500 μm or less, the above-mentioned totally reflected emitted light can reliably shine metallic or rainbow-colored.

[0016] In the invention of claim 6, the housing is formed with an accommodating 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 accommodating groove, and a step in which the light-transmitting member can be positioned on the groove edge side of the accommodating groove, thereby enabling the light guide, light source, and light-transmitting member to be positioned with high precision and making manufacturing easy. [Brief explanation of the drawings]

[0017] [Figure 1] 1A is a perspective view showing a lighting device of the present invention incorporated into a vehicle interior panel, and FIG. 1B is an exploded view showing the lighting device removed from the vehicle interior panel. [Figure 2] 1(a) is a front view of the vehicle interior panel, FIG. 1(b) is an enlarged cross-sectional view taken along line AA in FIG. 1(a), and FIG. 1(c) is an enlarged cross-sectional view taken along line BB in FIG. [Figure 3] 2(c) is an enlarged schematic cross-sectional view showing only the lighting device in the embodiment of FIG. 2(c), (b) is an enlarged view of part C in (a), and (c) is an enlarged view of part D in (b). [Figure 4] FIG. 2 is an exploded perspective view of the lighting device. [Figure 5] 1A is a front view of the lighting device, FIG. 1B is a cross-sectional view taken along line DD in FIG. 1A, and FIG. 1C is an enlarged cross-sectional view taken along line EE in FIG. 1A. [Figure 6] 1A is a front view of a single light-transmitting member constituting the lighting device, FIG. 1B is a rear view, and FIG. 1C is a top view. [Figure 7] The principle of the above-mentioned lighting device is shown in (a), where the light guide is not irradiated and external light incident from the front side is totally reflected by the fine unevenness and emitted from the surface, and (b) shows the state where the light from the light guide is further refracted by the fine unevenness and enters the translucent member, making the end of the protruding end face of the protrusion appear the brightest. [Figure 8] 3(a) shows modified example 1 corresponding to FIG. 3(b), and FIG. 3(b) shows modified example 2 corresponding to FIG. 3(c). [Figure 9] This is a conventional lighting device disclosed in Japanese Patent No. 6806358, where (a) shows FIG. 2 of the same publication and (b) shows FIG. 3 of the same publication. [Figure 10] This is a conventional configuration in which the light-transmitting member disclosed in Japanese Patent No. 5202602 appears plated (metallic or rainbow-colored) when exposed to external light. (a) shows Figure 2 from the same publication, and (b) shows Figure 4 from the same publication. DETAILED DESCRIPTION OF THE INVENTION

[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 1 to 6 will be explained, and then the main operational features will be clarified with reference to Figure 7, followed by a modified example shown in Figure 8. Note that hatching of the light-transmitting member and light guide body has been omitted in Figures 3, 7, and 8 to avoid cluttering the drawings.

[0019] As is clear from the drawings, the lighting device 2 has a structure in which a light-transmitting member 3 that transmits light and a light guide 4 that receives light from a light source such as an LED 28 are incorporated into a housing 20. Here, as shown in Figures 4 and 5, the housing 20 integrally comprises a horizontally grooved accommodation groove 21 that is elongated from side to side and can position and arrange the light guide 4, a recess 22 that is provided on one end of the accommodation groove 21 and can position and arrange 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 and arrange 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 arrangement section 22 from the opening side. The LED 28 is then positioned in a state in which an emission section 29 that emits light is fitted into a window 27 provided in the U-shaped partition wall, and the LED 28 abuts against 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 irradiated range is equal to or larger than the range of the fine concave-convex portion 38 of the light-transmitting member 3, which will be described later.

[0022] Although there are no particular restrictions on the material of the light guide 4, 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 Fig. 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] 4 and 6, the light-transmitting member 3 is composed of a base 30 in the shape of a long, narrow 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 claws 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 claws 23a into the recesses 34 and the protrusions 26 into the slits 33. In this state, a gap S, i.e., an air layer, is disposed between the light-transmitting member 3 and the light guide 4, as shown in FIG. This point is due to the air layer of the gap S, which is independent of the materials of the light-transmitting member and the light guide, as shown in Figure 7(b), and the refractive index of the light-transmitting member is greater than the refractive index on the light-entering side from the light guide, so total reflection does not occur and the irradiated light from the light guide passes through the light-transmitting member while being refracted.

[0024] As shown in FIG. 6(b), a 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 recesses 39 provided at predetermined intervals. As shown in FIG. 7, the fine irregularities 38 are arranged in a pattern with a substantially triangular cross section. Similar to the prism portion of Patent Document 2, the fine irregularities 38 are configured to totally reflect external light from a predetermined direction and emit it from the front, producing a metallic or rainbow-like sheen similar to plating. Specifically, the fine irregularities 38 are formed by repeatedly arranging convex or concave portions, with each convex portion forming a triangle with a base of approximately 10 to 50 μm and a height of approximately 25 to 50 μm. Various prototype tests have shown that it is preferable for the fine irregularities 38 to be formed by repeatedly arranging convex or concave portions at a pitch of 0.5 μm or more and 500 μm or less, and that the area of the fine irregularities 38 be wider than the protruding end faces of the protrusions 35 (described later).

[0025] A protrusion 35 is integrally formed on the front surface of the base 30. The protrusion 35 is provided so as to fit inside a number of minute concave-convex portions 38, and the upper and lower ends of the protrusion end face are formed as curved surfaces 36, while the left and right ends 37 are formed as inclined surfaces. In other words, of the protrusion end face, which is the front or design surface of the protrusion 35, the end of the protrusion end face is formed as a curved surface 36. This configuration allows the curved surface 36 forming the end of the protrusion end face 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 face 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 housing groove 21, the LEDs 28, which are light sources that introduce light into the light guide 4, are positioned in the recesses 22, and the light-transmitting member 3 is positioned in the steps 23, so that the light guide 4, the LEDs 28, and the light-transmitting member 3 can be accurately and easily assembled into the housing 2 to produce a commercial product. In addition, in this embodiment, the lighting device 2 is attached to a predetermined location that constitutes the instrument panel 1, as shown in Fig. 1. That is, in this example, a window 14 is provided between the upper portion 12 and the lower portion 13 that constitute the instrument panel 1, and the lighting device 2 is fixed to the panel 1 from the back side of the window 14 by means of screws or the like, with the protrusions 35 of the light-transmitting member inserted into the left and right groove-shaped window portions 14.

[0027] (Operation) FIG. 7 is a schematic diagram illustrating the operation of the above-described lighting device. First, FIG. 7(a) shows a state in which external light, such as sunlight or indoor light, is incident on the protruding end surface 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 unevenness 38 provided on the back surface of the base 30. Furthermore, 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 unevenness 38 and emitted toward the light guide 4. Then, as shown in FIG. 7(b), when the light guide 4 is turned on by the LED 28, the light from the light guide 4 is refracted into the light-transmitting member 3 by the fine unevenness 38 and enters, making it difficult for the light to be emitted from the front of the protruding portion 35 (weak light). When viewed from the front, the light appears metallic or iridescent, i.e., plated, like the reflected external light. Furthermore, as described above, external light is refracted and incident on the curved surface 36 around the protrusion 35, and as a result, reflection at the fine unevenness 38 is reduced, making the light from the light guide 4 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, light can be reliably irradiated to 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, strict control over the processing area of the fine unevenness 38 is not required, 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 metallic or rainbow-like. 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 shapes appear to float.

[0031] (Variation 1) Fig. 8(a) shows Variation 1 corresponding to Fig. 3(b). 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 enters the end around the protruding portion 35 while being refracted, which reduces reflection at the fine unevenness 38, making the light from the light guide 4 more visible, and making the inclined surface 37 appear the brightest. Note that the inclined surface 37 as described above may be inclined greatly from the protruding end face of the protruding portion 35 to the upper surface of the base 30.

[0032] (Variation 2) Fig. 8(b) shows Variation 2 corresponding to Fig. 3(c). In this variation, 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 larger 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. [Explanation of symbols]

[0034] 1. Part of the instrument panel (vehicle interior panel) 2. Lighting equipment 3...Translucent member (30 is a base, 35 is a protrusion) 4. Light guide 20... Housing (21 is a receiving groove, 25 is a recess, 23 is a step) 28: LED (light source, 29: emission part) 36... Curved surface (end of protruding end surface of protruding part) 37. Inclined surface (end of protruding end surface of protruding part) 38... Fine unevenness (L is the pitch of the concave or convex parts) S...Gap

Claims

1. A lighting device comprising a light source unit and a light-transmitting member that allows light from the light source unit to pass from a rear surface side to a design surface or a front surface, the light-transmitting member has a substantially plate-shaped base, a protruding portion that is integrated with the base and protrudes toward the opposite side to the light source portion, and a fine concave-convex portion that is provided on the back surface of the base facing the light source portion and that reflects external light that has entered from the protruding end surface side of the protruding portion and arrived in a predetermined direction, and causes the light to exit from the protruding end surface, thereby enabling the light to shine metallically or in rainbow colors; The lighting device is also characterized in that the end of the protruding end face of the protruding portion is formed into a curved surface or an inclined surface.

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

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

4. 3. The lighting device according to claim 2, wherein the light guide has an area equal to or larger than the area of the fine concave-convex portion.

5. 2. The lighting device according to claim 1, wherein the minute concave-convex portion is 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. 6. The lighting device according to claim 2, further comprising a housing that defines 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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