TWI648885B - Light emitting device - Google Patents

Abstract

The light emitting device comprises a light source, a light source carrier and a circuit board. The circuit board supplies power to the light source via the light source carrier. The circuit board comprises a metal substrate, the upper surface of which comprises a first electrode region, a second electrode region and a heat conducting region; a first metal electrode is formed on the first electrode region; a first insulating layer is formed on the a first metal electrode and the metal substrate; a second metal electrode formed on the second electrode region; a second insulating layer formed between the second metal electrode and the metal substrate; and a solder resist layer covering On the upper surface of the metal substrate; wherein the heat conduction region is exposed to the solder resist layer, and the heat conduction region is connected to the light source carrier.

Description

Illuminating device

The present invention relates to a light-emitting device, and more particularly to a light-emitting device capable of improving heat dissipation efficiency.

Light-emitting diodes (LEDs) have been widely used in various lighting devices because of their long life, small size, and low power consumption. In general, when the temperature of the light-emitting diode is increased, the luminous efficiency of the light-emitting diode is significantly lowered, and the service life of the light-emitting diode is shortened. As light-emitting diodes are increasingly being used in a variety of lighting applications, the heat dissipation problem of light-emitting diodes is even more important.

In the prior art, the substrate carrying the light-emitting diode is formed of aluminum oxide (Al ₂ O ₃ ) or other materials having insulating and high thermal conductivity to dissipate heat from the light-emitting diode. However, the thermal conductivity of the alumina material is still lower than that of the metal material, so the prior art cannot further improve the heat dissipation efficiency of the LED illumination device.

SUMMARY OF THE INVENTION An object of the present invention is to provide a light-emitting device which can improve heat dissipation efficiency to solve the problems of the prior art.

The light emitting device of the present invention comprises a light source, a light source carrier and a circuit board. The light source has a first electrode and a second electrode. The light source carrier comprises an insulating substrate, a first through hole and a second through hole are formed on the insulating substrate; a first upper metal pad is disposed on the insulating base The upper surface of the board is electrically connected to the first electrode; a second upper metal pad is disposed on the upper surface of the insulating substrate and electrically connected to the second electrode; a first conductor is disposed on the first surface a second conductor disposed in the second through hole; a first lower metal pad disposed on the lower surface of the insulating substrate and electrically connected to the first upper metal pad via the first conductor; a second lower metal pad is disposed on the lower surface of the insulating substrate, and is electrically connected to the second upper metal pad via the second conductor; and a third lower metal pad is disposed under the insulating substrate The surface is not electrically connected to the first metal electrode and the second metal electrode. The circuit board comprises a metal substrate having an upper surface and a lower surface, the upper surface comprising a first electrode region, a second electrode region and a heat conducting region; a first metal electrode formed in the first electrode region And a first metal layer is formed between the first metal electrode and the metal substrate; a second metal electrode is formed on the second electrode. And a second insulating layer is formed between the second metal electrode and the metal substrate; and an And a solder layer covering the upper surface of the metal substrate; wherein the heat conducting region is exposed to the solder resist layer, and the heat conducting region is connected to the third lower metal pad.

Compared with the prior art, the present invention utilizes a metal substrate as a circuit substrate of a light-emitting device, and the metal substrate has an exposed lower heat conduction region connected to the third lower metal pad of the light source carrier. The light-emitting device of the invention can use the light source carrier to quickly guide the heat generated by the light source during the light-emitting to the metal substrate via the heat-conducting region, and then dissipate the heat by the metal substrate. Therefore, the light-emitting device of the present invention has better heat dissipation efficiency.

10‧‧‧Lighting device

100‧‧‧Light source

110‧‧‧First electrode

120‧‧‧second electrode

200‧‧‧Light source carrier

202‧‧‧ solder paste

204‧‧‧heating materials

205‧‧‧Insert substrate

206‧‧‧First perforation

208‧‧‧Second perforation

210‧‧‧First lower metal pad

220‧‧‧Second lower metal pad

230‧‧‧ Third metal pad

240‧‧‧First upper metal pad

250‧‧‧Second upper metal pad

260‧‧‧First conductor

270‧‧‧second conductor

300‧‧‧ boards

310‧‧‧Metal substrate

320‧‧‧First metal electrode

322‧‧‧First oxidation resistant metal layer

330‧‧‧First insulation

340‧‧‧Second metal electrode

342‧‧‧Second antioxidant metal layer

350‧‧‧Second insulation

360‧‧‧ solder mask

370‧‧‧ board surface

372‧‧‧First electrode area

374‧‧‧Second electrode zone

376‧‧‧heat conduction zone

380‧‧‧Lower surface of the board

392‧‧‧First power electrode

394‧‧‧second power electrode

V1‧‧‧ first voltage

V2‧‧‧second voltage

Fig. 1 is a schematic view of a light-emitting device of the present invention.

Fig. 2 is a schematic view showing the lower surface of the light source carrier of Fig. 1.

Figure 3 is a schematic view of the upper surface of the circuit board of Figure 1.

Figure 4 is a schematic illustration of another embodiment of the lower surface of the light source carrier of the present invention.

Fig. 5 is a schematic view showing another embodiment of the upper surface of the circuit board of the present invention.

Please also refer to Figures 1 to 3. Fig. 1 is a schematic view of a light-emitting device of the present invention. Fig. 2 is a schematic view showing a first embodiment of the lower surface of the light source carrier of the present invention. Fig. 3 is a schematic view showing the first embodiment of the upper surface of the circuit board of Fig. 1. As shown, the light-emitting device 10 of the present invention comprises a light source 100, a light source carrier 200 and a circuit board 300. The light source 100 has a first electrode 110 and a second electrode 120. The light source carrier 200 is used to carry the light source 100. The light source carrier 200 includes an insulating substrate 205, a first upper metal pad 240, a second upper metal pad 250, a first conductor 260, and a second conductor 270. a first lower metal pad 210, a second lower metal pad 220, and a third lower metal pad 230. A first through hole 206 and a second through hole 208 are formed on the insulating substrate 205. The first upper metal pad 240 is disposed on the upper surface of the insulating substrate 205 and electrically connected to the first electrode 110. The second upper metal pad 250 is disposed on the upper surface of the insulating substrate 205 and electrically connected to the second electrode 120. The first conductor 260 is disposed within the first through hole 206. The second conductor 270 is disposed within the second through hole 208. The first lower metal pad 210 is disposed on the lower surface of the insulating substrate 205 and is electrically connected to the first upper metal pad 240 via the first conductor 260. The second lower metal pad 220 is disposed on the lower surface of the insulating substrate 205 and electrically connected to the second upper metal pad 250 via the second conductor 270. The third lower metal pad 230 is disposed on the lower surface of the insulating substrate 205 and is not electrically connected to the first lower metal pad 210 and the second lower metal pad 220.

The circuit board 300 includes a metal substrate 310, a first metal electrode 320, a first insulating layer 330, a second metal electrode 340, a second insulating layer 350, and a solder resist layer 360. The metal substrate 310 has an upper surface 370 and a lower surface 380. The upper surface 370 includes a first electrode region 372, a second electrode region 374, and a heat transfer region 376. The first electrode region 372 and the second electrode region 374 may be recessed regions formed by etching on the upper surface 370, but the invention is not limited thereto. The first metal electrode 320 is formed on the first electrode region 372. The first insulating layer 330 is formed Between the first metal electrode 320 and the metal substrate 310, the first metal electrode 320 and the metal substrate 310 are prevented from being turned on. The second metal electrode 340 is formed on the second electrode region 374. The second insulating layer 350 is formed between the second metal electrode 340 and the metal substrate 310 to prevent the second metal electrode 340 and the metal substrate 310 from being turned on. Due to the arrangement of the first insulating layer 330 and the second insulating layer 350, the heat conducting region 376 is not electrically connected to the first metal electrode 320 and the second metal electrode 340. The solder resist layer 360 is overlaid on the upper surface 370 of the metal substrate 310. The solder resist layer 360 can prevent the solder from flowing around and has an insulating function. The thermally conductive region 376 is exposed to the solder mask 360 and the thermally conductive region 376 can be directly or indirectly connected to the third lower metal pad 230. For example, the thermally conductive region 376 can be indirectly connected to the third lower metal pad 230 via a heat dissipating material 204 (eg, solder paste or thermal grease), and the thermal conductivity of the heat dissipating material is greater than 50 W/mK. In other embodiments of the invention, the thermally conductive region 376 can also be directly connected to the third lower metal pad 230, that is, the thermally conductive region 376 and the third lower metal pad 230 can be in direct contact.

In addition, as shown in FIG. 3, the circuit board of the present invention may further include a first power electrode 392 and a second power electrode 394. The first power electrode 392 can be electrically connected to the first metal electrode 320 for receiving a first voltage V1 (eg, a positive voltage), and the second power electrode 394 can be electrically connected to the second metal electrode 340 for receiving the phase. Different from the second voltage V2 of the first voltage V1 (for example, a ground voltage), the first metal electrode 320 can provide the first voltage V1 to the first lower metal pad 210 and further to the first electrode of the light source 100. 110, and the second metal electrode 340 can provide the second voltage V2 to the second lower metal pad 220 and further to the second electrode 120 of the light source 100 to drive the light source 100 to emit light.

According to the above configuration, when the light source 100 emits light, the heat energy generated by the light source 100 is transmitted to the light source carrier 200, and further transmitted to the heat conduction region 376 of the circuit board 300 via the third lower metal pad 230, so that the heat energy generated when the light source 100 emits light The heat conduction zone 376 can be quickly guided to the metal substrate 310, and the heat is dissipated by the metal substrate 310. In an embodiment of the invention, gold The substrate 310 may be a copper substrate. Since the thermal conductivity of the copper material is higher than the thermal conductivity of the alumina material, the circuit board 300 of the present invention can improve heat dissipation efficiency. Furthermore, since the light source 100, the light source carrier 200, and the circuit board 300 are electrically connected to each other by electrodes, the light-emitting device 10 of the present invention does not need to be wire bonded.

On the other hand, the solder resist layer 360 may be formed of a reflective material for reflecting the light emitted by the light source 100, so that the luminous efficiency of the light emitting device 10 can be improved. In an embodiment of the invention, the light source 100 can be a flip-chip light-emitting chip or a packaged light source component, such as a light source package component, but the invention is not limited thereto. Furthermore, the circuit board 300 of the present invention may further include a first oxidation resistant metal layer 322 formed on the first metal electrode 320 and a second oxidation resistant metal layer 342 formed on the second metal electrode 340. The first oxidation resistant metal layer 322 and the second oxidation resistant metal layer 342 may be formed of a material such as gold or silver to prevent oxidation of the first metal electrode 320 and the second metal electrode 340.

In the above embodiment, the light-emitting device 10 of the present invention includes only one light source 100. However, in other embodiments of the present invention, the light-emitting device of the present invention may include a plurality of light sources disposed on the light source carrier and connected in series and/or in parallel. Electrically connected to each other.

Please refer to FIG. 4, which is a schematic view of another embodiment of the lower surface of the light source carrier of the present invention. As shown in FIG. 4, the light source carrier 200' of the present invention may include a plurality of first lower metal pads 210, a plurality of second lower metal pads 220, and a plurality of third lower metal pads 230. The plurality of first lower metal pads 210 can be electrically connected to the first upper metal pads via the plurality of first conductors respectively to increase electrical connection reliability between the first lower metal pads and the first upper metal pads. The plurality of second lower metal pads 220 can be electrically connected to the second upper metal pads via the plurality of second conductors respectively to increase electrical connection reliability between the second lower metal pads and the second upper metal pads. A plurality of third lower metal pads 230 may be connected to the heat conduction region 376 of the circuit board 300 according to a heat dissipation design.

Please refer to FIG. 5, which is a schematic view of another embodiment of the upper surface of the circuit board of the present invention. As shown in Fig. 5, the circuit board 300' of the present invention may include a plurality of first metal electrodes 320 and a plurality of second metal electrodes 340. The plurality of first metal electrodes 320 can be electrically connected to the corresponding first lower metal pads, respectively, to increase electrical connection reliability between the first metal electrodes and the first lower metal pads. The plurality of second metal electrodes 340 can be electrically connected to the corresponding second lower metal pads respectively to increase electrical connection reliability between the second metal electrodes and the second lower metal pads.

In addition, the layout of the light source carrier and the circuit board of the present invention is not limited to the above embodiments, and the layout of the light source carrier and the circuit board of the present invention may be changed according to design requirements.

Compared with the prior art, the present invention utilizes a metal substrate as a circuit substrate of a light-emitting device, and the metal substrate has an exposed lower heat conduction region connected to the third lower metal pad of the light source carrier. The light-emitting device of the invention can use the light source carrier to quickly guide the heat generated by the light source during the light-emitting to the metal substrate via the heat-conducting region, and then dissipate the heat by the metal substrate. Therefore, the light-emitting device of the present invention has better heat dissipation efficiency.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

Claims (9)

A light-emitting device comprising: a light-emitting unit comprising a light source and a carrier, the light source being electrically connected to the carrier; and a circuit board comprising a metal substrate and a circuit layer, the circuit layer being disposed on the metal substrate Electrically isolating from the metal substrate, the metal substrate has a first upper surface and a second upper surface, the second upper surface surrounding the first upper surface and extending to an edge of the metal substrate, and the circuit layer is located at the Between the first upper surface and the second upper surface, wherein the carrier is electrically connected to the circuit layer, and the carrier is thermally conductively connected to the first upper surface of the metal substrate, wherein an entire lower surface of the metal substrate The outer surface is completely exposed, and the first upper surface of the metal substrate and the second upper surface are coplanar. A light-emitting device comprising: a light-emitting unit comprising a light source and a carrier, the carrier comprising an insulating substrate and a conductive layer disposed on the insulating substrate, the light source being electrically connected to the conductive layer; a circuit board comprising a metal substrate and a circuit layer, the metal substrate includes a first upper surface and a second upper surface, the second upper surface surrounding the first upper surface and extending to an edge of the metal substrate, and the circuit layer is located at the Between the first upper surface and the second upper surface, the first upper surface includes a heat conducting region, the circuit layer is disposed on the metal substrate and exposes the heat conducting region, and the circuit layer is electrically isolated from the metal substrate The light emitting unit is disposed on the circuit board and the conductive layer is electrically connected to the circuit layer; and a heat dissipating material is thermally conductively connected to the insulating substrate and the heat conducting region of the metal substrate, wherein one of the metal substrates The entire lower surface is completely exposed to the outside, and the first upper surface of the metal substrate and the second upper surface are coplanar. A light-emitting device comprising: a light-emitting unit comprising a light source and a carrier, the carrier comprising an insulating substrate and a conductive layer disposed on the insulating substrate, the light source being disposed on the insulating substrate and electrically connected to the conductive layer a circuit board comprising a metal substrate and a circuit layer, the metal substrate having a first upper surface, a second upper surface, and a recessed portion, the second upper surface surrounding the first upper surface and extending to the An edge of the metal substrate, and the recessed portion is located between the first upper surface and the second upper surface, the circuit layer is disposed in the recess and electrically isolated from the metal substrate, wherein the light emitting unit is disposed at the The conductive layer is electrically connected to the circuit layer; and a metal heat dissipating material is thermally conductively connected to the insulating substrate and the first upper surface of the metal substrate, wherein an entire lower surface of the metal substrate is completely opposite The outside is exposed, and the first upper surface of the metal substrate and the second upper surface are coplanar. The light-emitting device according to any one of claims 1 to 3, further comprising an insulating layer disposed between the circuit layer and the metal substrate. The light-emitting device according to claim 1 or 2, wherein the metal substrate has a depressed portion, and the wiring layer is disposed in the depressed portion. The illuminating device of claim 1, further comprising a metal heat dissipating material that thermally connects the carrier and the metal substrate. The illuminating device of claim 2, wherein the heat dissipating material comprises a metal heat dissipating material. The illuminating device of claim 1, wherein the circuit board further comprises a solder mask covering the metal substrate and exposing at least a portion of the wiring layer. The illuminating device of any one of claims 1 to 3, wherein the surface of the wiring layer further comprises an electrode protective layer.