Light source device with high heat-dissipation efficiency

A light source device includes a circuit board, a solid state lighting element, and a hollow cylindrical metal reflector. The circuit board has a circuit layer formed thereon. The solid state lighting element is placed on the circuit board and electrically connected to the circuit layer. The hollow cylindrical metal reflector is placed on the circuit board and insulated from the circuit layer. An inner surface of the reflector surrounds the solid state lighting element to reflect and direct light from the solid state lighting element towards an opposite side of the reflector to the solid state lighting element.

BACKGROUND

1. Technical Field

The disclosure relates to light source devices with high heat-dissipation efficiency.

2. Description of Related Art

Light emitting diodes, and specifically the electrical and optical characteristics and lifespan thereof, are easily influenced by temperature. High working temperatures can deteriorate internal quantum efficiency of the LED and shorten the lifespan thereof. Furthermore, resistance of the semiconductor generates a negative temperature coefficient and tends to be reduced with an increase in the working temperature. Such reduced resistance correspondingly results in stronger current at given voltages as well as the generation of excessive heat. If the excessive heat is not effectively dissipated, heat accumulation can lead to deterioration of the LED.

Referring toFIG. 4, a typical light source device10includes a shell11, a light source module12, and a cover13. The light source module12is received in the shell11. The cover13is located on and protects the light source module12. The light source module12includes a printed circuit board121, a circuit layer122, a number of lighting elements123(such as light emitting diodes), and an encapsulant124. The circuit layer122and lighting elements123are mounted on the printed circuit board121. The lighting elements123are electrically connected to the circuit layer122. The encapsulant124is positioned on the printed circuit board121to package the lighting elements123. While excessive heat from the light source module12is dissipated through the shell11, thermal conductivity thereof is less than optimal, such that the excessive heat is not effectively dissipated.

Therefore, there is room for improvement within the art.

DETAILED DESCRIPTION

Referring toFIG. 1, a first embodiment of a light source device20is provided. The light source device20includes a circuit board21, a solid state lighting element22, a reflector23, and an encapsulant24.

The circuit board21includes a first surface210and a second surface212opposite to the first surface210. A circuit layer214is formed on the first surface210of the circuit board21. The circuit board21may be made of Al2O3, AlN, BeO, or other ceramic materials. Alternatively, the circuit board21may be a silicon substrate, metal core printed circuit board (MCPCB), etc.

In the illustrated embodiment, the solid state lighting element22is a light emitting diode chip (LED chip), which is placed on the first surface210of the circuit board21and electrically connected to the circuit layer214.

Also referring toFIG. 5, the reflector23has a hollow column structure, such as a hollow cylinder. The reflector23can be made of metal such as copper, aluminum or other, thus the reflector23has good heat-dissipation efficiency. The reflector23is placed on the first surface210of the circuit board21and surrounds the solid state lighting element,22. An inner surface231of the reflector23surrounding the solid state lighting element22reflects and directs light60from the solid state lighting element22towards an opposite side of the reflector23to the solid state lighting element22, to change view angle of the solid state lighting element22. The reflector23may be connected to the circuit layer214via an insulating thermal conductivity of plastic50, so as to improve electrical insulation between the reflector23and the circuit board21. Because the reflector23has good heat-dissipation efficiency, heat from the solid state lighting element22is effectively dissipated by the reflector23away from the solid state lighting element22, thereby heat-dissipation efficiency of the light source device20is optimized.

The encapsulant24is received in the hollow reflector23to cover the solid state lighting element22for protection from mechanical damage, moisture, and atmospheric exposure. The encapsulant24may be a condenser lens to collect light from the solid state lighting element22and redirects it upwards, such that the light path of the light source device20can be altered. The encapsulant24may be epoxy resin, silicone resin, or other electrically insulating transparent materials. The encapsulant24may further include a plurality of phosphor particles doped therein. For example, the solid state lighting element22may be a blue LED chip and the phosphor particles a yellow phosphor, whereby the yellow phosphor, excited by blue light from the solid state lighting element22, emit yellow light, with white light formed by the combination of yellow and original blue light emits out from the lampshade traverse the encapsulant24. The phosphor particles may be YAG phosphor, TAG phosphor, silicate phosphor, nitride phosphor, etc.

Referring toFIG. 2, a second exemplary embodiment of a light source device30is similar to the first embodiment of the light source device20, except that a plurality of fins333radially extends from an outer surface332of a reflector33, to increase heat radiating area of the reflector33, the heat-dissipation efficiency of the light source device30may be further improved. The fins333may be connected to the circuit layer214via an insulating thermal conductivity of plastic50a, so as to form a thermally connection between the tins333and the circuit layer214. Alternatively, the tins333may be isolated to the circuit layer214.

Referring toFIG. 3, a third exemplary embodiment of a light source device40is similar to the first embodiment of the light source device20, except that light source device40includes a reflector43and a heat conductor45.

The reflector43differs from reflector23of the first embodiment in that an outer surface432of a reflector43has outer threads thereon.

The heat conductor45differs from reflector23of the first embodiment in that an inner surface451of a heat conductor45has inner threads thereon, and a plurality of fins453radially extends from an outer surface452of the reflector43, so that the heat conductor45can be threadingly engaged with the reflector43, the assembly flexibility of the light source device40may be improved. Because the heat conductor45and the reflector43have good heat-dissipation efficiency as the reflector23of the first embodiment, heat from a solid state lighting element42is effectively dissipated by the reflector43and the heat conductor45away from the solid state lighting element42, thereby heat-dissipation efficiency of the light source device40is optimized. It can be understood that, the heat conductor45may be mechanically engaged with the reflector43in other fashion, such as concave and convex matching, so long as the heat conductor45can be detachably mounted to the reflector43. In addition, the solid state lighting element42is a light emitting diode in the illustrated embodiment.