Patent Application
20140293649
1. Field of the Invention
The present invention relates to an illumination device and an automotive lamp and, in particular, an illumination device and an automotive lamp using light control members such as a light guide and a lens.
2. Description of the Related Art
In the conventional practice, known as an automotive lamp used for a tail lamp and a stop lamp is a lamp configured such that the light emitted from a light source, such as LEDs, is incident on one end surface of a rod-like light guide and is then emitted from the peripheral surface of the light guide toward a front area (see Patent Document 1, for instance).
[Patent Document 1] Japanese Unexamined Patent Application Publication (Kokai) No. 2011-003281.
The light control members, such as the light guide and lens, used for the automotive lamp are generally formed of a transparent resin such as acrylic or polycarbonate. Thus the peripheral surfaces of the light guide and the lens have transparent appearances and there is still room for improvement in their textures. As a method for improving the texture on the appearance of resin molding products, the surface texturing (embossment) is conventionally known where the asperities are formed on the resin molding products.
If, however, the surface texturing is done on the peripheral surface of the light guide, the light is not totally reflected on emboss-finished surfaces and part of the light passes through outside and therefore the light cannot be sufficiently guided up to a part of the light guide located away from the light source. This makes it hard for the light guide to be controlled so that the light is desirably distributed through the light guide. Also, if the surface texturing is done on the lens, a desired light distribution may not be achieved.
The present invention has been made in view of the foregoing circumstances, and a purpose thereof is to provide an illumination device and an automotive lamp using light control members capable of improving the texture on the appearance thereof while the light distribution is appropriately controlled by the light control members.
In order to resolve the above-described problems, an illumination device includes: a light source mounting part for mounting a light source thereon; and a light control member configured to emit light frontward by controlling the light emitted from the light source. The light control member includes a plurality of steps with which the light emitted from the light source is controlled. A pitch of the plurality of steps is less than or equal to 0.5 mm.
By employing this embodiment, the pitch between the plurality of steps formed in the light control member is set to 0.5 mm or below. Thus, a viewer can be given an impression as if the light control member were subjected to the surface texturing. As a result, the texture on the appearance of the illumination device can be improved. Also, the embossed appearance thereof is achieved by adjusting the pitch of the steps, so that a desired light distribution can be achieved unlike in the case where the surface texturing is actually done on the light control member.
The light control member may be a light guide that has the light, emitted from the light source, enter from one end surface thereof and that emits the light frontward from an emission surface along an extending direction by guiding the light inside the light guide. The plurality of steps of the light guide may reflect the light traveling inside the light guide toward the emission surface. The plurality of steps may include a plurality of triangle-shaped steps.
The light control member may be a lens where a plurality of steps are formed in order to emit the light, emitted from the light source, as light having a required light distribution characteristic. The plurality of steps formed in the lens may include a plurality of fish-eye steps arranged in grids. The plurality of steps formed in the lens may include a plurality of cylindrical steps arranged side by side in a predetermined direction.
A radius of curvature R of each of the plurality of steps formed in the lens may be set such that R≦1 mm. When a pitch between each of the plurality of steps formed in the lens is denoted by P, the radius of curvature R of each step may be set such that R≦P×2.
Another embodiment of the present invention is an automotive lamp including the above-described illumination device.
Embodiments will now be described by way of examples only, with reference to the accompanying drawings which are meant to be exemplary, not limiting and wherein like elements are numbered alike in several Figures in which:
Hereinafter, a detailed description is given of embodiments of the present invention with reference to drawings. In the following embodiments, first to third embodiments each shows an automotive lamp, which is an illumination device, applied to a vehicle. A fourth embodiment shows a ceiling lamp, which is also an illumination device, used mainly for interior illumination. A fifth embodiment shows a street lamp, which is also an illumination device, used mainly for outdoor illumination.
The automotive lamp 10 includes a lamp body 14 and a transparent cover 12, which covers an opening in front of the lamp body 14. The lamp body 14 and the cover 12 form a lamp chamber 16. And an LED 18 and a light guide 20 are provided inside the lamp chamber 16.
The light guide 20 is a rod-like member produced through the injection molding of a transparent resin such as acrylic or polycarbonate. Although, in
One of end surfaces of the light guide 20 functions as an incident surface 20a that receives light emitted from the LED 18. A front side on the peripheral surface of the light guide 20 functions as an emission surface 20b that emits the light. A plurality of steps, with which the light traveling inside the light guide 20 is reflected toward the emission surface 20b, are formed, on a rear face 20c on the peripheral surface of the light guide 20, along an extending direction of the light guide 20. The “steps” will be discussed later.
The LED 18 is a light source that provides light into the light guide 20. The LED 18 is mounted on a light source mounting part 19 fixed to a side of the lamp body 14 such that the LED 18 faces the incident surface 20a of the light guide 20.
A description is now given of an operation of the automotive lamp 10 configured as described above. Light rays emitted from the automotive lamp 10 are shown in
A detailed description is now given of the steps formed in the light guide 20.
The paths of light entering inside the light guide 20 from the incident surface 20a are shown in the cross-sectional view of
In the present embodiment, a plurality of steps 24 are arranged so that a pitch P is in a range of 0.3 mm to 0.5 mm (both inclusive). Arranging the steps 24 such that the pitch P is set between 0.3 mm and 0.5 mm allows the viewer to see, when the light guide 20 is viewed from an emission surface 20b side, as if the emission surface 20b underwent the surface texturing. As a result, the texture of the light guide 20 can be improved.
As shown in
It is evident from
As described above, by employing the automotive lamp 10 according to the first embodiment, the pitch between the plurality of steps 24 formed on a rear face 20c side of the light guide 20 is set in a range of 0.3 mm to 0.5 mm (both inclusive). Thus, the viewer can be given an impression as if the light guide were subjected to the surface texturing. As a result, the texture on the appearance of the automotive lamp 10 can be improved. Also, in the first embodiment, the embossed appearance thereof is achieved by adjusting the pitch of the steps 24, so that the light can be sufficiently guided up to a part of the light guide 20 located away from the LED 18 and therefore the light guide 20 can be controlled to produce a desired light distribution, unlike in the case where the surface texturing is actually done on the light guide.
Although, in the automotive lamp 10 according to the present embodiment, the LED is used as the light source, other light sources such as a bulb may be used instead.
The automotive lamp 60 includes a lamp body 64 and a transparent outer lens 62, which covers an opening in front of the lamp body 64. The outer lens 62 is so formed as to be curved from a front area of the lamp toward the right and left sides. The lamp body 64 and the outer lens 62 form a lamp chamber 66. And provided inside the lamp chamber 66 are a bulb 68 functioning as a light source, a bulb socket 67 serving as a light source mounting part, a reflector 69 reflecting the light emitted from the bulb 68, and an inner lens 70 that controls the direct light from the bulb 68 and the light reflected from the reflector 69 and then emits them toward the outer lens 62.
The bulb 68 is supported by the bulb socket 67, which is mounted to the lamp body 64, so as to be electrically connected thereto. The reflector 69 is so provided as to surround the bulb 68 from a back side of the bulb 68 and is supported by the lamp body 64.
The inner lens 70 is formed along the outer lens 62 and is supported by the lamp body 64. An emission surface 70b of the inner lens 70 (i.e., a surface of the inner lens 70 on an outer lens 62 side) is spaced apart by a predetermined distance from the outer lens 62. A plurality of steps, which is used to control the direct light from the bulb 68 and the light reflected from the reflector 69, are formed on an incident surface 70a (i.e., a surface of the inner lens 70 on a bulb 68 side).
A detailed description is now given of the steps formed in the inner lens 70.
As shown in
In the present embodiment, a plurality of fish-eye steps 72 are arranged so that the pitch P is in a range of 0.3 mm to 0.5 mm (both inclusive). Although the pitches in two array directions of steps, which are perpendicular to each other, are identical, they may differ from each other instead. Arranging a plurality of fish-eye steps 72 such that the pitch P is set between 0.3 mm and 0.5 mm allows the viewer to see, when the inner lens 70 is viewed from an emission surface 70b side, as if the inner lens 70 underwent the surface texturing. As a result, the texture of the inner lens 70 can be improved.
The fish-eye steps 72 may be formed such that a radius of curvature R thereof satisfies P/2≦R≦1 mm. Or alternatively, the fish-eye steps 72 may be formed such that the radius of curvature R thereof satisfies P/2≦R≦P×2. Where these conditions are met, the incident light can be extensively diffused. Further, where these conditions are met, the radius of curvature R is relatively small and thus an angular aperture becomes larger or a magnifying power becomes larger. As a result, the depth of focus becomes narrower and an object looks blurry. This can suppress the components built in the lamp chamber (e.g., electric circuits) from being seen through and can improve designability of lamps.
As shown in
As described above, by employing the automotive lamp 60 according to the second embodiment, the pitch of fish-eye steps formed on the incident surface 70a of the inner lens 70 is set in a range of 0.3 mm to 0.5 mm (both inclusive). Thus, the viewer can be given an impression as if the inner lens were subjected to the surface texturing. As a result, the texture on the appearance of the automotive lamp 60 can be improved. Also, in the second embodiment, the embossed appearance thereof is achieved by adjusting the pitch of the fish-eye steps, so that the direct light from the bulb 68 and the light reflected from the reflector 69 can be controlled as designed in the first place so as to produce a desired light distribution, unlike in the case where the surface texturing is actually done on the light guide.
In the above-described second embodiment, the convex-shape fish-eye steps 72 are formed on the incident surface 70a of the inner lens 70. In substitution for or in addition to these convex-shape fish-eye steps, concave-shape fish-eye steps may be formed. Also, the fish-eye steps 72 may be provided over approximately entire region of the incident surface 70a of the inner lens 70 or may be provided on a partial region thereof. Also, in the above-described second embodiment, the fish-eye steps 72 are formed on the incident surface 70a of the inner lens 70. In substitution for or in addition to these fish-eye steps, the fish-eye steps may be formed on the emission surface 70b of the inner lens 70.
The automotive lamp 100 includes a lamp body 104 and a lens 102, which covers an opening in front of the lamp body 104.
In the automotive lamp 100 according to the present embodiment, a plurality of steps are formed on an internal surface of the lens 102 (an incident surface of the lens 102 receiving the light from the light bulb 108). These steps may be similar to the fish-eye steps 72 formed in grids shown in
A plurality of steps formed on the internal surface of the lens 102 are arranged so that the pitch P is in a range of 0.3 mm to 0.5 mm (both inclusive). Arranging a plurality of steps such that the pitch P is set between 0.3 mm and 0.5 mm allows the viewer to see, when the lens 102 is viewed from an emission surface side, as if the lens 102 underwent the surface texturing. As a result, the texture of the lens 102 can be improved.
The steps formed on the internal surface of the lens 102 may be formed such that the radius of curvature R thereof satisfies P/2≦R≦1 mm. Or alternatively, these steps may be formed such that the radius of curvature R thereof satisfies P/2≦R≦P×2. Where these conditions are met, the incident light from the light bulb 108 can be extensively diffused. Further, where these conditions are met, the radius of curvature R is relatively small and thus the angular aperture becomes larger or the magnifying power becomes larger. As a result, the depth of focus becomes narrower and an object looks blurry. This can suppress the components built in the lamp chamber 106 (e.g., the electric circuit 110) from being seen through and can improve designability of lamps.
As shown in
In the ceiling lamp 120 according to the present embodiment, a plurality of steps are formed on an internal surface 122a of the cover 122 (an incident surface of the cover 122 receiving the light from the lamp 124). These steps may be similar to the fish-eye steps 72 formed in grids shown in
A plurality of steps formed on the internal surface 122a of the cover 122 are arranged so that the pitch P is in a range of 0.3 mm to 0.5 mm (both inclusive). Arranging a plurality of steps such that the pitch P is set between 0.3 mm and 0.5 mm allows the viewer to see, when the cover 122 is viewed from an emission surface 122b side, as if the cover 122 underwent the surface texturing. As a result, the texture of the cover 122 can be improved.
The steps formed on the internal surface 122a of the cover 122 may be formed such that the radius of curvature R thereof satisfies P/2≦R≦1 mm. Or alternatively, these steps may be formed such that the radius of curvature R thereof satisfies P/2≦R≦P×2. Where these conditions are met, the incident light from the lamp 124 can be extensively diffused. Further, where these conditions are met, the radius of curvature R is relatively small and thus the angular aperture becomes larger or the magnifying power becomes larger. As a result, the depth of focus becomes narrower and an object looks blurry. This can suppress the components built in the lamp chamber 123 (e.g., the lamp mounting part 125 and the electric circuit 126) from being seen through and can improve designability of the ceiling lamp 120.
In the present embodiment, the lamp 124 may be a lamp using the LED and the light guide used in the automotive lamp 10 described and shown in the first embodiment. In such a case, in substitution for or in addition to the formation of the aforementioned plurality of steps on the internal surface 122a of the cover 122, a plurality of steps having the pitch ranging from 0.3 mm to 0.5 mm may be formed on the light guide, similarly to the automotive lamp 10 according to the first embodiment. This can allow a viewer to be given an impression as if the light guide were subjected to the surface texturing. As a result, the texture on the appearance of the ceiling lamp 120 can be improved.
Although, in the present embodiment, the ceiling lamp 120 is exemplified as an illumination device for indoor use, the illumination device for indoor use is not limited thereto and it may be, for example, a pendant lamp hung from the ceiling using chains or the like.
As shown in
In the street lamp 130 according to the present embodiment, a plurality of steps are formed on an internal surface 132a of the cover 132 (an incident surface of the cover 132 receiving the light from the lamp 134). These steps may be similar to the fish-eye steps 72 formed in grids shown in
A plurality of steps formed on the internal surface 132a of the cover 132 are arranged so that the pitch P is in a range of 0.3 mm to 0.5 mm (both inclusive). Arranging a plurality of steps such that the pitch P is set between 0.3 mm and 0.5 mm allows the viewer to see, when the cover 132 is viewed from an emission surface 132b side, as if the cover 132 underwent the surface texturing. As a result, the texture of the street lamp 130 can be improved.
The steps formed on the internal surface 132a of the cover 132 may be formed such that the radius of curvature R thereof satisfies P/2≦R≦1 mm. Or alternatively, these steps may be formed such that the radius of curvature R thereof satisfies P/2≦R≦P×2. Where these conditions are met, the incident light from the lamp 134 can be extensively diffused. Further, where these conditions are met, the radius of curvature R is relatively small and thus the angular aperture becomes larger or the magnifying power becomes larger. As a result, the depth of focus becomes narrower and an object looks blurry. This can suppress the components built in the lamp chamber 133 (e.g., the lamp mounting part 135 and an electric circuit (not shown)) from being seen through and can improve designability of the street lamp 130.
In the present embodiment, the lamp 134 may be a lamp using the LED and the light guide used in the automotive lamp 10 described and shown in the first embodiment. In such a case, in substitution for or in addition to the formation of the aforementioned plurality of steps on the internal surface 132a of the cover 132, a plurality of steps having the pitch ranging from 0.3 mm to 0.5 mm may be formed on the light guide, similarly to the automotive lamp 10 according to the first embodiment. This can allow a viewer to be given an impression as if the light guide were subjected to the surface texturing. As a result, the texture on the appearance of the street lamp 130 can be improved.
Although, in the present embodiment, the street lamp 130 is exemplified as an illumination device for outdoor use, the illumination device for outdoor use is not limited thereto and it may be, for example, an outdoor light mounted on a house's external wall or the like.
The present invention has been described based upon illustrative embodiments. These embodiments are intended to be illustrative only and it will be obvious to those skilled in the art that various modifications to constituting elements and processes could be developed and that such modifications are also within the scope of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-004097 | Jan 2012 | JP | national |
| 2012-145692 | Jun 2012 | JP | national |
| 2012-188321 | Aug 2012 | JP | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2012/008079 | Dec 2012 | US |
| Child | 14306799 | US |
