Patent Application
20150103552
1. Technical Field
The present invention relates to a light source device of a lamp installed in a vehicle such as an automobile and more particularly to a light source device of which heat dissipation effect has been increased and to a vehicular lamp including the light source device.
2. Related Art
There has been proposed, as a light source of a vehicular lamp, a light source device including a semiconductor light-emitting element such as an LED. In this type of light source device, particularly a light source device including an LED, thermal run-away is caused when the LED itself overheats due to heat generated by the LED. Accordingly, the light-emitting characteristics of the LED are deteriorated, or lifetime of the LED is shortened. Patent Document 1 describes a technology in which a heat dissipation member is accommodated in a lamp boss of the light source module structured including an LED, and the lamp boss facing the heat dissipation member is provided with heat dissipation holes. According to this technology, the heat generated by the LED is transferred to the heat dissipation member, and dissipated to the outside air through the heat dissipation holes of the heat dissipation member.
It is assumed that the light source module according to the technology of Patent Document 1 is mounted on the socket that is separately provided. Therefore, the light source module is disposed inside the lamp housing isolated from the outside air when the light source module is mounted on the vehicular lamp having a sealed lamp housing structured by a lamp body and a front lens. Accordingly, when light is emitted from the light source module, air is circulated only inside the lamp housing even though the heat is dissipated from the heat dissipation member with the air flowing through the heat dissipation holes provided in the lamp boss. As the time elapses, temperature of the air inside the lamp housing increases, and the heat dissipation effect gradually decreases. As described above, in the light source module described in Patent Document 1, the heat dissipation effect is insufficient even though it includes the heat dissipation member and the heat dissipation holes. Therefore, it is difficult to effectively prevent the LED from overheating.
One or more embodiments of the present invention provides a light source device and a vehicular lamp that enable heat to be dissipated by air at a low temperature while the light source device is mounted on the lamp and that have excellent heat dissipation effect.
According to one or more embodiments of the present invention, a light source device includes a light-emitting element structure body including a light-emitting element, a base member fitted in a lamp, and an installation portion which is provided in the base member and on which the light-emitting element structure body is installed. The light source device is characterized in that a heat dissipation chamber communicating with an outside of the light source device in the base member is formed inside the installation portion.
In one or more embodiments of the present invention, a high thermal conductive member partially exposed at the outside the device is provided or disposed in the heat dissipation chamber. In one or more embodiments of the present invention, a heat dissipation hole is provided in the base member so that the heat dissipation chamber communicates with the outside of the device. Particularly, in one or more embodiments of the present invention, the base member is mounted on a part of a member that separates the lamp chamber into a front side chamber and a rear side chamber, and in a state where the base member is mounted on the part of the member, the light-emitting element is positioned in the front side chamber of the lamp, and the heat dissipation chamber communicate with the rear side chamber of the lamp.
A vehicular lamp according to one or more embodiments of the present invention is comprises the light source device according to one or more embodiments of the present invention.
According to one or more embodiments of the present invention, the heat generated when the light-emitting element emits light is transferred from the light-emitting element structure body to the installation portion. The heat dissipation chamber is formed inside the installation portion. The heat dissipation chamber communicates with the outside of the light source device in the base member. Therefore, in the installation portion having an inner surface in contact with the heat dissipation chamber, the heat is dissipated by an air flowing through the heat dissipation chamber, that is, the air in an area at a lower temperature than the area where the light-emitting element is present. Even though a temperature inside the lamp chamber increases due to light emitted from the light source device, the heat is dissipated at the installation portion by the air of a lower temperature than that in the installation portion. Therefore, the light dissipation effect of the light-emitting element is enhanced.
Also, according to one or more embodiments of the present invention, the high thermal conductive member is provided or disposed in the heat dissipation chamber so that the high thermal conductive member dissipates the heat at the installation portion to the outside of the device. Therefore, the heat dissipation effect can be enhanced compared to the case where the heat dissipation chamber is hollow. Further, the heat dissipation hole communicating with the heat dissipation chamber is provided so that the circulation of the air in the heat dissipation chamber is promoted by the air flowing through the heat dissipation hole. Accordingly, the heat dissipation effect can be enhanced.
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In embodiments of the invention, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid obscuring the invention.
Commonly known bayonet pieces 51 are formed on the front end of the outer peripheral surface of the base member 2. A flange 52 is formed in a circular shape on the outer peripheral surface of the base member 2 separated by a predetermined dimension in the axial direction from the bayonet pieces 51. The bayonet portion 5 is formed of the bayonet pieces 51 and the flange 52, and allows the light source device 1 to be attached and detached to and from the light source attachment hole 106 provided in the reflector 105. For such attachment and detachment, a waterproof ring 53 is fitted to the front surface of the flange 52. The waterproof ring 53 makes it possible to achieve waterproof and airtightness effects at the light source attachment hole 106 when the light source device 1 is attached to the light source attachment hole 106.
A connector cylinder 41 is integrally formed with the connector portion 4 at a position close to the rear end of the outer peripheral surface of the base member 2, that is, a position corresponding to the left groove 21L, so that the cylinder axis heads in a direction orthogonal to the axis of the base member 2. The connector cylinder 41 has an inner portion communicating with the left groove 21L. A plurality of connector terminals 42 (three terminals) are arranged in parallel along the cylinder axis inside the connector cylinder 41 and supported by an insulating panel member 43 so as to be accommodated in the connector cylinder 41. The connector terminals 42 are formed of a conductive member, in this case, formed by bending a thin and long metal plate. Each of distal ends 42a is structured as a connecting end portion for connecting the external connector 6 shown by the chain line in
As shown in
The LED structure body 3 includes a printed circuit board bended generally in a U shape in the thickness direction, in this case a flexible printed circuit (FPC) board 31, as shown in
The LED structure body 3 is installed on the installation portion 22 from the front surface side of the base member 2. For this installation, the left piece 31L and the right piece 31R of the FPC board 31 is inserted to the left groove 21L and the right groove 21R, respectively. The back surface of the center piece 31C is in contact with the front surface of the installation portion 22. The positioning recesses 33 of the center piece 31C are fitted to the positioning pins 23 of the installation portion 22, and the LED structure body 3 is positioned to the installation portion 22. Then, the back surface of the LED structure body 3 is fixed to the installation portion 22 by adhesion, etc. By installing the LED structure body 3 as described above, the distal end of the left piece 31L is fitted in the base ends 42b of the connector terminals 42 of the connector portion 4 as shown in
The light source device 1 having the above configuration is fitted in the light source attachment hole 106 of the clearance lamp CLL provided in the reflector 105 with the bayonet portion 5 as shown in
The rear portion of the base member 2 is exposed at the rear side chamber 103r of the lamp chamber 103 as shown in
In addition, the air in the rear side chamber 103r, which is at a relatively low temperature, passes through the inside of the heat dissipation holes 25 communicating with the heat dissipation chamber 24. Accordingly, the outside air in the heat dissipation chamber 24 is circulated without stagnation as shown by the arrow in broken line in
As described above, in the light source device 1 according to one or more embodiments of the present invention, the heat can be dissipated from the light source device 1, particularly from the LED structure body 3, by the air in the rear side chamber 103r, which is at a relatively low temperature because the heat is insulated by the reflector 105, that is, by the extension 104, even though the temperature in the front side chamber 103f of the lamp chamber 103 increases due to the heat generated in the light source device 1. Therefore, the heat dissipation effect is enhanced, enabling a temperature increase in the LED structure body 3 to be suppressed.
In addition, the connector terminals 42 are inserted from the front surface side of the base member 2 when the connector terminals 42 are accommodated in the connector portion 4. Therefore, connector insertion grooves 26 are formed in the installation portion 22 so as to extend in the axial direction in order to insert the connector terminals 42 from the front surface toward the rear surface. The connector insertion grooves 26 provided correspond to the number of the connector terminals 42. Here, three connector terminals 42 are disposed. Therefore, three connector insertion grooves 26 are provided aligned in a direction perpendicular to the paper of
According to one or more embodiments of the present invention, inside the installation portion 22, the heat dissipation chamber 24 is opened in an area so as not to interfere with the left groove 21L, the right groove 21R, and the connector insertion grooves 26 along the axial direction from the front surface of the installation portion 22. The heat dissipation chamber 24 is extended to a portion close to the rear surface of the base member 2, and closed and ended in the vicinity of the connection portion with the connector portion 4. The heat dissipation holes 25 penetrating the base member 2 in the radial direction are provided in a part of the outer peripheral surface of the base member 2, and the heat dissipation holes 25 communicate with the heat dissipation chamber 24.
Further, according to one or more embodiments of the present invention, a space to form the heat dissipation chamber 24 is restricted due to the connector insertion grooves 26 formed on the installation portion 22. Therefore, it is difficult to increase the volume of the heat dissipation chamber 24 and enlarge the area of the installation portion 22 contacting the heat dissipation chamber 24. Consequently, a high thermal conductive member 27, such as metal powder, metal particle, or metal plate, and high thermal conductive resin, is disposed in the heat dissipation chamber 24 from the opening formed on the front surface of the installation portion 22. In addition, for example, a lid element 28 formed of another member is adhered to the opening of the heat dissipation chamber 24 so as to close the opening. As a method for charging the high thermal conductive member 27 in the heat dissipation chamber 24, for example, the high thermal conductive resin that is melting is disposed in the heat dissipation chamber 24, and the high thermal conductive resin may be cooled and hardened. The high thermal conductive member 27 may be disposed in the heat dissipation chamber 24 excluding the heat dissipation holes 25. Here, the high thermal conductive member 27 is disposed in the area extending from the heat dissipation chamber 24 to the heat dissipation holes 25, and as shown in
In the light source device 1A according to one or more embodiments of the present invention, excluding that the external connector 6 (see
Here, the opening of the heat dissipation chamber 24 that opens in the front surface of the installation portion 22 is closed with the lid element 28 after the high thermal conductive member 27 is disposed in the heat dissipation chamber 24. However, the opening is closed by hardening when the high thermal conductive resin is used for the high thermal conductive member 27. Therefore, the lid element 28 is not required. In addition, even though the high thermal conductive member 27 other than resin is disposed, and the opening is kept open, the opening can be airtightly sealed by closely contacting the back surface of the FPC board 31 when the LED structure body 3 is installed on the installation portion thereafter. Therefore, in this case as well, the lid element 28 may not be required.
The structure in which the high thermal conductive member 27 is disposed in the heat dissipation chamber 24 to enhance the heat dissipation effect may be similarly applied to the light source device 1 in any of the embodiments of the present invention, even if not shown in the drawings. In the case where the high thermal conductive member 27 is disposed in the heat dissipation chamber 24 according to one or more embodiments of the present invention, the heat transferred from the LED structure body 3 to the installation portion 22 is transferred from the installation portion 22 up to the rear surface of the base member 2 at which the high thermal conductive member 27 is exposed. The heat is dissipated by the air in the rear side chamber 103r from the rear surface. Note that the heat dissipation holes 25 communicating with the heat dissipation chamber 24 may not be particularly provided because heat conductive efficiency up to the rear surface of the base member 2 is enhanced by the high thermal conductive member 27.
One or more of the above embodiments describe the example of the structure in which the light source attachment hole 106 is provided in the reflector 105, that is, the extension 104, accommodated in the lamp housing 100, and the light source device 1 is fitted in the light source attachment hole 106. However, one or more embodiments of the present invention may be applied to a lamp having a structure in which the light source device 1 is fitted to a support member provided separately from the reflector and disposed inside the lamp housing, for example, a support frame or a support portion provided integrally with an inner lens. In this case as well, when the reflector or the support member separates the lamp chamber 103 into the front side chamber 103f in which the LED is positioned and the rear side chamber 103r isolated from the front side chamber 103f by the reflector or the support member, the heat dissipation effect of the light source device 1 can be enhanced by adopting a structure in which the heat dissipation chamber provided in the light source device is exposed at the rear side chamber.
In addition, one or more embodiments of the present invention may be applied to a lamp having a structure in which the light source attachment hole is provided in the rear surface of the lamp body 101, and the light source device is fitted in the light source attachment hole. In this case, the front side chamber in the light source device 1 corresponds to the inside of the lamp housing 100, that is, the lamp chamber 103, and the rear side chamber corresponds to the outside of the lamp housing 100, that is, the outside air area. Accordingly, the heat in the heat dissipation chamber in the light source device 1 is dissipated by the outside air outside the lamp housing 100.
In one or more of the embodiments described above, the example including the bayonet portion 5 for fitting the light source device 1 or 1A in the light source attachment hole 106 is shown. However, as long as the light source device is fitted in the light source attachment hole 106, installation structures using screws or other methods may be adopted. In addition, in one or more of the above embodiments, the bayonet portion 5 is disposed on a position close to the front end of the base member 2. However, the bayonet portion 5 may be disposed on the center position in the front-rear direction or a position close to the rear end. Further, the connector portion 4 is not limited to a structure in which the external connector 6 is fitted to the connector portion 4, and may be a cable connector directly running the electric cable from the LED structure body 3.
One or more of the embodiments described above shows an example in which the chip based LED is installed to the FPC board in the LED structure body as the light-emitting element structure body. However, a discrete LED may be used, or a light source device on which a semiconductor limit-emitting element is installed may be used. Further, the FPC board is not limited to a metal base FPC or a FPC having a reinforcement plate on its back surface but may be configured with the normal printed circuit board (PCB).
Above, one or more embodiments of the present invention is applied to a light source device of a clearance lamp. However, for the light source device of the lamp that adopts the semiconductor light-emitting element including LED as a light source, one or more embodiments of the present invention may be configured as a light source device of other lamps such as a tail lamp (including a stop lamp, back-up lamp), a daytime running lamp (DRL) or a turn signal lamp (TSL).
In one or more embodiments of the present invention, the semiconductor light-emitting element is used as a light source, and the light source may be adopted for a lamp and its light source device which are accommodated in the lamp chamber.
While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013-215155 | Oct 2013 | JP | national |
