High power LED substrate structure and high power LED lamp

Abstract

The present invention relates to a high-power LED substrate architecture, including an aluminum nitride ceramic substrate for fixing an LED chip, and also including a lower substrate fixed under the aluminum nitride ceramic substrate, and the aluminum nitride ceramic substrate also includes a blind hole filled with a low-melting-point metal for transferring heat to the lower substrate. The present invention uses aluminum nitride ceramic as an upper substrate, and injects a low-melting-point metal into the blind hole on the aluminum nitride ceramic substrate, adopts a large-area double-sided copper-clad plate as a lower substrate, and arranges a low-melting-point metal layer between the double-layer substrates, and at the same time, a heat-conducting copper column is provided at the position of the lower substrate corresponding to the chip. The present invention isolates the heat conduction channel and the electrical conduction channel, and uses a high thermal conductivity material to open a maximum heat sink channel for the heat dissipation of the LED chip, and the thermal conductivity coefficient is maintained at about 200W / m·K, thereby avoiding the brightness attenuation of the LED chip due to temperature rise and improving the working efficiency of the chip.

Description

Technical Field

[0001] The invention relates to a high-power LED substrate structure and a lamp having the LED substrate structure. Background Art

[0002] The power of LED lighting can only be increased if the heat dissipation of LED chips is done well. Currently, most LED lighting lamps use single-layer substrates. The heat dissipation of the chip is often blocked by the insulation layer. The thermal conductivity of the insulation layer is only a few percent of the thermal conductivity of the metal. Poor heat dissipation has become the main reason for the decline in LED light efficiency and insufficient service life. Therefore, improving light efficiency and extending the service life of devices requires solving the problem of heat conduction.

[0003] The materials currently used for LED substrates are mainly aluminum nitride ceramics, alumina ceramics, fiberglass boards, copper, aluminum and other metals. Aluminum nitride ceramics have the best thermal conductivity, which can reach 210W / m·K, while the thermal conductivity of alumina is 30W / m·K and the thermal conductivity of fiberglass boards is 0.2W / m·K.

[0004] When using insulating materials as substrates, copper-clad circuit boards are also required for electrical conduction. When using metal materials such as copper and aluminum as LED substrates, an insulating layer must be made, and then a conductive circuit must be printed on the insulating layer, and then an insulating heat-insulating layer must be applied. Although copper and aluminum are both good conductors of heat (copper 400W / m·K, aluminum 220W / m·K), the thermal conductivity drops directly to 3W / m·K after applying the insulating layer. The traditional single-layer substrate structure inevitably has an insulating layer on the heat conduction channel, that is, it inevitably has a thermal barrier layer. The heat generated when the chip is working accumulates on the thermal barrier layer, causing the chip temperature to rise. Summary of the invention

[0005] In order to solve the problem of temperature rise caused by poor heat dissipation of the existing LED substrate, the present invention provides a high-power LED substrate structure and a lamp.

[0006] The technical solution adopted by the present invention is as follows: a high-power LED substrate architecture, including an aluminum nitride ceramic substrate for fixing an LED chip, and a lower substrate fixed under the aluminum nitride ceramic substrate, and the aluminum nitride ceramic substrate also includes a blind hole filled with a low-melting-point metal for transferring heat to the lower substrate.

[0007] Preferably, a low melting point metal layer for mutual wetting and welding is further included between the aluminum nitride ceramic and the lower substrate.

[0008] Preferably, the area of ​​the lower substrate is larger than that of the aluminum nitride ceramic substrate.

[0009] Preferably, the area of ​​the lower substrate is 8 times the area of ​​the aluminum nitride ceramic substrate.

[0010] Preferably, the surface adjacent to the upper substrate of the lower substrate is a conductive and heat-conductive metal layer, which is divided into independent conductive areas and thermal conductive areas, wherein the thermal conductive areas correspond to the position of the chip of the upper substrate, and the conductive areas correspond to the peripheral circuits of the chip.

[0011] Preferably, the lower substrate is a double-sided printed circuit board.

[0012] Preferably, the low melting point metal is copper.

[0013] Preferably, the lower substrate is a copper-clad laminate, or an aluminum-based copper-clad laminate.

[0014] In one embodiment of the present invention, the lower substrate has a through hole at a position corresponding to the chip on the aluminum nitride ceramic substrate, and the through hole is filled with a heat-conducting round copper column. Preferably, the heat-conducting round copper column is wettably welded to the conductor layer on the upper and lower surfaces of the lower substrate.

[0015] The present invention also provides a high-power LED lamp, which uses any one of the high-power LED substrate structures described in the present invention.

[0016] The beneficial effects of the present invention are as follows: aluminum nitride ceramic is used as the upper substrate, and a low melting point metal is injected into the blind hole on the aluminum nitride ceramic substrate, a large area double-sided copper clad plate is used as the lower substrate, a low melting point metal layer is arranged between the double-layer substrates, and a heat-conducting copper column is provided at the position of the lower substrate corresponding to the chip. The present invention isolates the heat conduction channel and the electrical conduction channel, and uses high thermal conductivity materials to open a maximum heat sink channel for the heat dissipation of the LED chip, and the thermal conductivity coefficient is maintained at about 200W / m·K, thereby avoiding the brightness attenuation of the LED chip due to temperature rise and improving the working efficiency of the chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the LED substrate architecture of the present invention.

[0018] Figure 2 It is a schematic diagram of the structure of two chips on the LED substrate of the present invention.

[0019] Figure 3 It is a structural schematic diagram of an embodiment of the LED substrate architecture of the present invention.

[0020] Figure 4 FIG. 1 is a top view of an embodiment of an LED substrate structure of the present invention. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings. The implementation of the present invention is not limited to the embodiments described below, and can also be implemented in many different forms. The purpose of providing the following embodiments is to facilitate a more thorough and comprehensive understanding of the content disclosed in the present invention.

[0022] It should be noted that, when the present specification describes an original being "fixed" to another original, it means that the original is directly on the other original, or there are other intermediate originals in between; when the present specification describes an element being "connected" to another element, it means that the original is directly connected to the other element, or there are intermediate elements in between.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. The terms used herein are only for describing specific embodiments and are not intended to limit the present invention.

[0024] The high-power LED substrate architecture of the present invention adopts an LED chip flip-chip structure, and uses aluminum nitride ceramics as the upper substrate. Heavy ion bombardment is used to form a multi-blind hole structure in the heat dissipation area, and then the holes are expanded by cleaning and filled with low-melting-point thermal conductive metal to form a high thermal conductivity channel. In order to reduce costs, the area of ​​the upper substrate can be equivalent to the chip distribution area, improve the use efficiency of aluminum nitride ceramics, and construct an unobstructed thermal channel. The lower substrate adopts a copper-based copper-clad plate or an aluminum-based copper-clad plate, and its area is 9 times that of the upper substrate. In addition to the conductive function, the lower substrate mainly serves as an effective heat sink for the upper substrate to quickly disperse the heat generated by the chip horizontally. Low-melting-point metal materials are filled between the upper and lower substrates to further improve the thermal conduction channel, and the thermal conduction channel is separated from the conductive channel.

[0025] like Figure 1 The figure shows a composite structure diagram of an LED light board 100 of the present invention. The chip 1 is flipped and fixed on an upper substrate 2 made of aluminum nitride ceramic material, the upper substrate 2 is fixed on a lower substrate 3, a low melting point metal material 4 is filled between the upper substrate 2 and the lower substrate 3, a blind hole 21 is provided inside the upper substrate 2, and a low melting point metal material is filled inside the blind hole 21. The material of the lower substrate 3 is a copper clad plate or an aluminum-based copper clad plate.

[0026] like Figure 2 , which is a schematic diagram of the structure of two chips on the LED substrate of the present invention. The light board 100 includes two chips 1, each chip 1 further includes two chip pins 105, the chip pins 105 are respectively connected to the copper pins 307 on the lower substrate 3, and the copper pins 307 on the lower substrate 3 are connected to the circuit of the PVC board. There is a blind hole 21 in the upper substrate 2 corresponding to each chip, and there is a low melting point heat dissipation material 4 in the lower substrate 3 corresponding to the blind hole 21.

[0027] Each LED chip has two positive and negative pins 105. A flip chip is used here. Since the volume of its pins is relatively large, its heat dissipation effect is much better than that of a face-mounted chip. A blind hole 21 is opened in the aluminum nitride ceramic of the upper substrate 2, and a heat-conducting metal is filled in the blind hole 21. The heat-conducting metal is connected to the lower substrate 3, ensuring that the heat of the upper substrate 2 is quickly transferred to the lower substrate 3.

[0028] It can be seen that the upper substrate is divided into a heat conduction area and a conductive area. The portion where the blind hole 21 is located is the heat conduction area, and the portion where the chip pin 105 is connected to the copper pin 307 is the conductive area.

[0029] The lower substrate is also divided into a heat conduction area and a conductive area. The heat conduction area at the bottom of the upper substrate corresponds to the heat conduction area on the upper surface of the lower substrate. The low-melting-point metal filled in the blind hole inside the upper substrate is infiltrated and welded with the metal filled in the heat conduction partition of the lower substrate, and they fuse together to form a heat conduction channel.

[0030] like Figure 3 The figure shows an embodiment of a double-layer substrate of the present invention. The aluminum nitride upper substrate 2 after die bonding has multiple blind holes 21. The LED chip 1 is located on the upper substrate 2. The upper surface of the upper substrate 2 is engraved with the chip layout (including the chip and its pins, and the perforations corresponding to the pin connections, Figure 3 The lower surface of the upper substrate 2 (the surface adjacent to the lower substrate 3) is provided with a heat dissipation area and a conductive circuit. The pattern and area of ​​the heat dissipation area are consistent with the pattern of the heat dissipation area on the upper surface of the lower substrate 3.

[0031] The lower substrate 3 is a double-sided copper-clad glass fiber board, on whose upper surface a conductive circuit area 33 and a heat-conducting area 31 are engraved. The upper area 32 is connected to the chip pins and also includes a conductive circuit area 33. The heat-conducting area 31 is a copper-clad layer. Since the core of the glass fiber board of the lower substrate 3 is glass fiber material with low thermal conductivity, a copper column 34 is embedded in the heat-conducting area to improve the heat conduction from the upper surface to the lower surface of the lower substrate. Areas 32 and 33 are separate, 32 represents the connecting part of the upper and lower substrate conductive electrodes, and 33 represents the unwashed copper-clad part of the upper surface of the lower substrate. The chip distribution area on the upper surface of the upper substrate is designed as a heat channel area. Corresponding to the chip distribution area, the same pattern is planned on the lower surface of the upper substrate and the upper surface of the lower substrate as a heat sink channel. The conductive channels of the LED chips are respectively led out on the upper substrate, corresponding to the conductive area of ​​the lower substrate, connected by welding, and finally connected and led out on the upper surface of the lower substrate. The lower surface of the lower substrate is completely used as a heat dissipation surface and will be completely fitted with the heat sink.

[0032] Figure 3 The illustrated embodiment establishes a longitudinal heat path from the chip, the upper substrate, to the upper and lower surfaces of the lower substrate.

[0033] The copper-clad layer 35 on the lower surface of the lower substrate is the lower surface of the entire lamp panel component and is the main radiating surface for dissipating heat to the outside, so its area is 9 times that of the upper substrate.

[0034] 34 is a heat-conducting copper column that penetrates and fills the lower substrate. The upper surface of the lower substrate and the lower surface of the upper substrate can also be melted and connected with a low-melting-point metal to make heat conduction more reliable.

[0035] The small area of ​​the upper substrate 2 can reduce the amount of aluminum nitride material used, thereby reducing material costs, and also help to compactly arrange workpieces during solid crystal production, thereby improving production efficiency.

[0036] like Figure 4 The figure shows a top view of an embodiment of the double-layer substrate structure of the present invention, where the upper substrate 2 is located on the lower substrate 3, and the upper substrate 2 includes a heat conduction area 22 and a conductive area 23. The heat conduction area 22 is located in the middle of the upper substrate 2 and is used to connect the chip 1 (the chip is not shown in the figure), and the conductive area 23 includes two independent areas corresponding to the positive and negative electrodes. The lower substrate 3 has a larger area than the upper substrate 2.

[0037] In one embodiment of the present invention, the flip-chip structure of the LED chip has a double-layer substrate, and a low-melting-point metal is used between the upper substrate and the lower substrate to improve the thermal conductivity. In addition, a blind hole is opened in the aluminum nitride ceramic of the upper substrate, and the blind hole is filled with a thermally conductive metal, which is connected to the lower substrate by infiltration welding, further improving the thermal conductivity.

[0038] In one embodiment of the present invention, through holes are formed in the upper substrate to achieve connection between the chip pins and the circuit wires on the copper clad board.

[0039] The present invention makes full use of the excellent thermal conductivity of aluminum nitride to construct an efficient thermal conductive channel to transfer heat to the lower substrate. The lower substrate can use copper or aluminum as the substrate material, and the heat dissipation channel and the conductive channel are respectively connected by welding.

[0040] When there are multiple chips, the upper substrate has multiple chips. No matter how many chips there are, the upper substrate of the current design can carry them. Just change the area and pattern, and the layout structure of the upper substrate can be adjusted according to the Figure 4 The same arrangement as shown is distributed on the lower substrate.

[0041] The conductive electrodes on the upper surface of the lower substrate are the result of the arrangement of all chips, and the input voltage can be designed according to the needs of the user.

[0042] The heat dissipation pattern is mainly designed based on the chip distribution to ensure maximum vertical heat conduction.

[0043] The LED substrate structure of the present invention avoids the heat resistance of the electrical insulation layer on the substrate heat channel, and maintains the thermal conductivity of the heat dissipation channel at about 200W / m·K, which is 8 times higher than the 25W / m·K of the existing product. This means that the power density of LED lighting will likely increase by 8 times, greatly improving the quality of lighting products with concentrated light intensity.

[0044] The projector floodlight using the LED substrate architecture of the present invention was tested under the working state of the projector. It worked continuously for 24 hours without a black screen under the condition of doubling the power, while the lamp board using the traditional substrate would have a black screen after 2 hours. This shows that the high-power LED substrate architecture of the present invention can effectively reduce the light output temperature for high-power density floodlights, greatly expanding the application scenarios of high-power LEDs.

[0045] The LED substrate structure of the present invention can be used in high-power projectors, street lamps, and marine lamps.

[0046] The technical features of the above-mentioned embodiments can also be combined in other ways. For the sake of brevity, all possible combinations of technical features are not fully described here. It is hereby declared that as long as there is no contradiction in the combination of these technical features, they all fall within the scope of this specification.

[0047] The above embodiments specifically and in detail describe several implementation methods of the present invention, which is not a limitation on the scope of the invention patent. For those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention shall belong to the protection scope of the present invention, and the protection scope of the patent of the present invention shall be subject to its claims.

Claims

1. A high-power LED substrate structure, comprising an aluminum nitride ceramic substrate for fixing an LED chip, characterized in that: It also includes a lower substrate fixed under the aluminum nitride ceramic substrate, and the aluminum nitride ceramic substrate also includes a blind hole filled with a low melting point metal for transferring heat to the lower substrate; The lower substrate is a double-sided printed circuit board; The surface of the lower substrate adjacent to the aluminum nitride ceramic substrate is a conductive and thermally conductive metal layer, which is divided into a conductive area and a thermally conductive area independent of each other, wherein the thermally conductive area corresponds to the position of the chip on the aluminum nitride ceramic substrate, and the conductive area corresponds to the peripheral circuit of the chip; The blind hole on the aluminum nitride ceramic substrate corresponds to the heat conduction area of ​​the lower substrate; The lower substrate has a through hole at a position corresponding to the chip on the aluminum nitride ceramic substrate, and the through hole is filled with a heat-conducting round copper column.

2. The high power LED substrate structure according to claim 1, wherein: A low melting point metal layer for mutual wetting and welding is also included between the aluminum nitride ceramic substrate and the lower substrate.

3. The high-power LED substrate structure according to claim 1 or 2, characterized in that: The area of ​​the lower substrate is larger than that of the aluminum nitride ceramic substrate.

4. The high-power LED substrate structure according to claim 3, characterized in that: The area of ​​the lower substrate is 8 times that of the aluminum nitride ceramic substrate.

5. The high-power LED substrate structure according to claim 3, wherein: The low melting point metal is copper.

6. A high power LED lamp, characterized in that: A high-power LED substrate structure as claimed in any one of claims 1 to 5 is used.

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