JP2005310892A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device provided with a heat dissipation element that is superior in heat dissipation efficiency. <P>SOLUTION: The light emitting device is provided with a light emitting element and a block-like heat sink element that is provided with a plurality of heat dissipation walls arranged like comb teeth to radiate a heat of the light emitting element in an air and a heat transmitter to transmit the heat of the light emitting element to the heat dissipation walls, and a cavity forming a passage of air in the heat transmitter is provided along the light emitting element arranged like a row. The cavity is formed along a direction crossing orthogonally the adjacent direction of the heat dissipation walls. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to, for example, a light-emitting device that is employed as a light-emitting source of an in-vehicle display device, and more particularly to a heat dissipation structure thereof.

This type of light-emitting device is disclosed in, for example, Patent Document 1. In addition to a light emitting diode as a light emitting element, such a light emitting device includes a heat dissipation element that dissipates heat generated from the light emitting diode into the air. The heat dissipating element is made of a metal block having good thermal conductivity, and includes a heat transfer portion and a heat dissipating fin, and heat generated from the light emitting diode is combed at a predetermined interval via the heat transfer portion. A heat dissipation method is adopted in which heat is transferred to the flat heat dissipation fins arranged in a tooth shape and exposed to heat in the atmosphere. In order to further increase the heat dissipation effect, a method of dissipating heat using a fan or the like that blows air by rotating a plurality of wings is employed.
Japanese Patent Laid-Open No. 2003-104086

  In the light-emitting device having the above-described configuration, the heat transfer portion has a temperature distribution in which the temperature just below the light-emitting element is the highest and the temperature is lower toward the periphery. Thus, although it is effective to cool the high temperature region immediately below the light emitting element, there is a problem that it is difficult to cool the heat transfer portion located immediately below the light emitting element constituted by the solid part. On the other hand, a structure is conceivable in which the groove between the heat radiating fins is deepened (the heat transfer portion is thinned) to shorten the distance between the light emitting element and the heat radiating fin so that heat is easily transferred to the heat radiating fin. However, if the distance between the light emitting element and the heat radiating fin is set close, heat is easily transferred to the heat radiating fin immediately below the light emitting element, but heat is not easily transferred to the heat radiating fin located at a position away from the light emitting element. It becomes impossible to utilize the heat dissipation effect throughout.

  In view of such a problem, an object of the present invention is to improve heat dissipation efficiency in a light emitting device including a light emitting element and a heat dissipation element.

  In order to solve the above problems, the present invention provides a light emitting element, a plurality of heat dissipating wall portions arranged in a comb shape to dissipate heat of the light emitting element into the air, and heat of the light emitting element on the heat dissipating wall portion. A block-shaped heat dissipating element having a heat transfer section for transferring, and a cavity for forming an air flow path is provided in the heat transfer section.

  According to the second aspect of the present invention, a plurality of the light emitting elements are provided in a row, and the cavity is provided along the row of the light emitting elements.

  According to a third aspect of the present invention, the hollow portion is formed along a direction orthogonal to the adjacent direction of the heat radiating wall portion.

  In the present invention, as described in claim 4, irregularities are provided in the hollow portion.

  As described in claim 5, the present invention is provided with a blowing means for sending a fluid to the cavity or an introducing means for causing the fluid to flow into the cavity.

  ADVANTAGE OF THE INVENTION According to this invention, the light-emitting device excellent in heat dissipation efficiency can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  1, 2 and 3 are views showing a light emitting device 1 which is a first embodiment of the present invention.

  The light emitting device 1 includes a light emitting diode 2 which is a light emitting element, a substrate 3 to which the light emitting diode 2 is connected and fixed, and a heat radiating element 4. The heat dissipating element 4 is composed of a block-shaped heat transfer portion 5 and a heat dissipating wall portion (hereinafter referred to as a heat dissipating fin) 6, and a material having high thermal conductivity such as aluminum or copper is used for extrusion molding or the like. It is formed by.

  A substrate 3 is provided on one surface of the heat transfer section 5 by a fixing member 8 with an electric insulating member (hereinafter referred to as a heat conductive sheet) 7 interposed therebetween. The substrate 3 is a printed substrate 3 made of aluminum having high thermal conductivity, and is provided on the substrate 3 so as to form a light emitting diode row 2a in which a plurality of light emitting diodes 2 are arranged in a row.

  The heat conductive sheet 7 is a sheet-like heat conductive electrical insulating member, and improves the adhesion between the metal substrate 3 and the metal heat transfer portion 5 to increase the conduction efficiency. As the fixing member 8, a screw or a bolt is used, and the substrate 3, the heat conductive sheet 7, and the heat transfer unit 5 are fixedly disposed.

  The heat transfer part 5 is provided with a hollow part 9. The hollow portion 9 is provided in a cylindrical shape along the place where the light emitting diode rows 2a are installed, and the inner wall of the hollow portion 9 is provided with unevenness for increasing the surface area and increasing the heat dissipation effect. As a result, a fluid (air) flow path is formed in the heat transfer section 5. Thus, by providing a flow path along the light-emitting diode array 2a in the solid portion immediately below the light-emitting diode 2 that tends to be high temperature in the heat transfer section 5, and sending the fluid from the opening 9a, the high-temperature region is directly set. It is possible to dissipate heat and the heat dissipating effect is enhanced.

  The heat radiating fin 6 is formed by providing a flat plate member in a comb-teeth shape on the surface facing the surface on which the light emitting diode 2 is installed. Since the gap and the cavity 9 of each radiation fin 6 serving as an air flow path are provided with an air inlet 6a (opening 9a in the cavity) in the same direction, the cavity 9 is generated by the air flow in one direction. In addition, the heat radiation efficiency in the heat radiation fins 6 can be improved, and also in the formation of the heat radiation element 4, since the extrusion molding can be easily performed, the manufacturing cost can be suppressed.

  The heat transfer section 5 has a rectangular parallelepiped shape with a thickness. For example, when the heat transfer section 5 is thin and flat, the heat generated from the light emitting diode 2 reaches the heat radiation fin 6 via the substrate 3, the heat conductive sheet 7 and the heat transfer section 5, but is separated from the light emitting diode 2. It is difficult for heat to be transmitted to the heat dissipating fins 6 located at the place. This is because heat concentrates on the heat radiating fins 6 provided in the vicinity of the light emitting diode 2. Therefore, this embodiment has a structure in which the heat transfer section 5 is made into a block shape and has a thickness so that the heat transfer section 5 diffuses heat to the surroundings and the heat is easily transferred to all the radiation fins 6. .

  In the present embodiment, the light emitting diode 2 is provided on the substrate 3. However, the light emitting diode 2 may be used as long as it does not have to be the light emitting diode 2 and generates heat. In addition to the light emitting element, a driving circuit for the light emitting element and an IC chip, a heat generating electronic component such as a resistor and a transistor, and a driving circuit such as a constant voltage circuit and a constant current circuit for driving these electronic components are provided on the substrate. Also good.

  In addition, the inner wall of the cavity portion 9 has irregularities, but the shape of the cavity portion is arbitrary, and as shown in FIG. 9b may be provided as long as the fluid passes therethrough.

  Further, the hollow portion 9 may not be provided linearly as in the first embodiment, and may be a meandering cylindrical shape as long as it is provided along the heat generating element.

  As shown in FIG. 5, a cylindrical intake port (duct) 10 that draws fluid as an introducing means may be provided in the opening 9a. Moreover, you may provide the dedicated fan which ventilates by rotation as a ventilation means which sends a fluid in the cavity part 9 from the opening part 9a.

  As a second embodiment of the present invention, as shown in FIG. 6, an opening 9 a is provided on the surface where the heat dissipating fins 6 of the heat transfer section 5 are provided, and the cavity 9 is bent into an L shape. The position of the opening may be arbitrary.

The figure which shows 1st embodiment of this invention. The figure which shows the side surface of embodiment same as the above. Sectional drawing of embodiment same as the above. The figure which illustrates the cavity part shape of embodiment same as the above. The figure which shows embodiment same as the above provided with the inlet (duct). The figure which shows 2nd embodiment same as the above.

Explanation of symbols

1 Light Emitting Device 2 Light Emitting Element (Light Emitting Diode)
4 Heat-dissipating element 5 Heat transfer part 6 Heat-dissipating wall part (radiating fin)
9 Cavity 9a Opening 10 Inlet (duct)

Claims (5)

A light emitting element;
A block-shaped heat dissipating element having a plurality of heat dissipating wall portions arranged in a comb shape and dissipating heat of the light emitting element into the air, and a heat transfer portion transmitting heat of the light emitting element to the heat dissipating wall portion. ,
A light emitting device, wherein a cavity for forming an air flow path is provided in the heat transfer unit.   The light emitting device according to claim 1, wherein a plurality of the light emitting elements are provided in a row, and the cavity is provided along the row of the light emitting elements.   The light emitting device according to claim 1, wherein the hollow portion is formed along a direction orthogonal to an adjacent direction of the heat radiating wall portion.   The light emitting device according to claim 1, wherein unevenness is provided in the hollow portion.   The light-emitting device according to claim 1, further comprising a blowing unit that sends a fluid to the cavity or an introducing unit that causes the fluid to flow into the cavity.

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