Dimmable inverted COB light source

Abstract

The invention relates to a light-adjustable flip COB light source which comprises an aluminum substrate, a normal white flip COB unit, a warm white flip COB unit and a control circuit. The control circuit comprises a power input end, a dimming control end and a dual-channel LED constant-current driving module, the dual-channel LED constant-current driving module is connected with the power input end, the dimming control end, the normal white flip COB unit and the warm white flip COB unit, and the normal white flip COB unit and the warm white flip COB unit each comprise a chip bonding pad set and a flip chip. The flip chips are connected with the chip bonding pads in a one-to-one correspondence mode through the eutectic technology, the head ends of the chip bonding pad sets are all connected to the constant-current driving module, and the tail ends of the chip bonding pad sets are all connected to the power input end. The dimming control end is provided with an interface for inputting two paths of dimming signals, the dual-channel LED constant-current driving module converts the two paths of dimming control signals into constant-current signals and drives the normal white flip COB unit and the warm white flip COB unit to emit light, and the flip chip technology is adopted to realize gold-thread-free COB packaging, so that the risk of fracture of a normal COB gold thread is avoided; and the reliability of the product is obviously improved.

Description

Technical Field

[0001] The invention relates to the field of LED light source manufacturing, and in particular to a dimmable flip-chip COB light source. Background Art

[0002] With the development of LED technology, it is widely used in the lighting industry. At the same time, the market has put forward higher requirements for the brightness, reliability, and installation convenience of LEDs. In this way, the COB (Chip On Board, chip integrated into the substrate) packaging form came into being. At present, the more mature is the COB with a positive structure. The positive chip is fixed on the substrate, and the electrical connection between the chips and the chip and the substrate circuit is completed using gold wire (or alloy wire). Then the fluorescent glue containing phosphors is coated to synthesize the required light color and protect the internal devices. The disadvantages of this structure of COB are very obvious: it is easy to break the line and die, low temperature resistance, low power density, and the solid crystal (mounting the chip on the substrate) process takes a long time. The traditional COB packaging structure also has some disadvantages, such as low thermal conductivity of the substrate insulation layer, uneven power of each chip in the COB, high void rate after chip welding, thick welding layer between the chip and the substrate, and high junction temperature when the chip is working normally. In addition, the traditional COB can only provide a light source with fixed color temperature and brightness, which cannot meet the personalized dimming needs of customers. Summary of the invention

[0003] In view of the above problems, the present invention discloses a dimmable flip-chip COB light source, which adopts a flip-chip structure to achieve gold-wire-free COB packaging and has the characteristics of adjustable color temperature and brightness, thus avoiding the risk of gold wire breakage in the traditional COB packaging structure.

[0004] The specific technical solutions are as follows:

[0005] A dimmable flip-chip COB light source comprises an aluminum substrate, a white flip-chip COB unit, a warm white flip-chip COB unit and a control circuit; the control circuit is located in the middle of the aluminum substrate, the control circuit comprises a power input terminal, a dimming control terminal and a dual-channel LED constant current drive module, the dual-channel LED constant current drive module is respectively connected to the power input terminal, the dimming control terminal, the white flip-chip COB unit and the warm white flip-chip COB unit, the white flip-chip COB unit and the warm white flip-chip COB unit are both arranged in a ring shape and are located at the periphery of the control circuit, the white flip-chip COB unit and the warm white flip-chip COB unit are respectively connected to the power input terminal, the dimming control terminal ... dimming control terminal, the dimming control terminal, the dimming control terminal, the dimming control terminal, the dimming control terminal, the dimming control terminal, the dimming control terminal, the dimming control terminal, the dimming control terminal, the dimming control terminal, the dimming control terminal, the dimming control terminal, the dimming control terminal, the dimming control terminal, the dimming control terminal, the dimming control terminal, the dimming control terminal, the dimming control terminal, the dimming control terminal, the dimming control terminal, the dim The COB units each include a chip pad group and a flip chip distributed in a ring shape, the chip pad group is composed of a number of chip pads connected end to end in sequence, and a number of the flip chips are connected to the chip pads one by one through a eutectic process, the head ends of the two chip pad groups are connected to a constant current drive module, and the ends of the two chip pad groups are connected to a power input end; the dimming control end is provided with an interface for inputting two dimming signals, and the dual-channel LED constant current drive module converts the two dimming control signals into constant current signals and drives the positive white flip-chip COB unit and the warm white flip-chip COB unit to emit light.

[0006] As a further optimization solution of the present invention, the power input terminal includes power input terminal 1 and power input terminal 2, and the power input terminal 1 and power input terminal 2 are two connectors with buckles.

[0007] As a further optimization scheme of the present invention, three circular dams are provided in sequence from the outside to the inside on the periphery of the aluminum substrate, and annular areas are formed between adjacent dams, wherein the normal white flip-chip COB unit is arranged in one of the annular areas, and the warm white flip-chip COB unit is arranged in the other annular area, and the annular areas between adjacent dams are filled with mixed fluorescent glue to cover the normal white flip-chip COB unit and the warm white flip-chip COB unit.

[0008] As a further optimization solution of the present invention, the dual-channel LED constant current driver module model is SM2612EN-LED lighting driver chip.

[0009] As a further optimization scheme of the present invention, the control circuit also includes resistors R1, R2, R3, R4, R5, R6, R7, and R8. The second power input terminal is respectively connected to one end of the resistors R1 and R7, the positive electrode of the positive white flip-chip COB unit, and the positive electrode of the warm white flip-chip COB unit. The first port of the dimming control terminal is respectively connected to the resistors R3 and R6, and the second port of the dimming control terminal is respectively connected to the resistors R2 and R4; the 1st, 2nd, 3rd, and 4th pins of the dual-channel LED constant current drive module are respectively connected to the resistors R2, R5, R3, and R8, the 5th pin of the dual-channel LED constant current drive module is connected to the negative electrode of the positive white flip-chip COB unit, the 6th pin of the dual-channel LED constant current drive module is connected to the negative electrode of the warm white flip-chip COB unit, and the 8th pin of the dual-channel LED constant current drive module is connected to the resistor R1; the first power input terminal is respectively connected to the resistors R4, R5, R6, R7, R8 and the 9th pin of the dual-channel LED constant current drive module.

[0010] The present invention also provides a method for manufacturing a dimmable flip-chip COB light source, which specifically comprises the following steps:

[0011] Step 1: Take the pre-made aluminum substrate and evenly spray flux on the chip pad surface of the positive white flip-chip COB unit and the warm white flip-chip COB unit;

[0012] Step 2: Complete flip chip eutectic on a fully automatic eutectic machine;

[0013] Step 3: Take the aluminum substrate with eutectic completed as above, and print solder paste on the pads of the components to be mounted on the top layer of the PCB;

[0014] Step 4: Place the power input terminal 1 connector, power input terminal 2 connector, dimming control terminal interface, dual-channel LED constant current driver module, and resistors R1, R2, R3, R4, R5, R6, R7, and R8 on the corresponding pads printed with solder paste;

[0015] Step 5: Place the aluminum substrate into a reflow oven to complete the welding of components and PCB;

[0016] Step 6: Use a dispensing machine with white silicone to make three circular dams with different radii according to the silk-screen frame on the aluminum substrate;

[0017] Step 7: Place the aluminum substrate into an oven to cure the silicone;

[0018] Step 8: Fill the pre-configured pure white fluorescent glue at the pure white flip-chip COB unit, and fill the pre-configured warm white fluorescent glue at the warm white flip-chip COB unit;

[0019] Step 9: Place the aluminum substrate into an oven to cure the fluorescent glue in sections;

[0020] Step 10: Complete the photoelectric parameter test on the photoelectric testing machine and retain qualified products.

[0021] As a further optimization scheme of the present invention, in step 2, the eutectic conditions are eutectic temperature 320-330°C, vacuum degree 10 -3 ~10 -5 Torr.

[0022] As a further optimization solution of the present invention, in step six, the spacing between adjacent dams is equal.

[0023] As a further optimization scheme of the present invention, in step seven, the curing temperature is 130° C. and the curing time is 30 minutes.

[0024] As a further optimization scheme of the present invention, in step nine, the first stage curing temperature is 100°C, and the curing time is 30 minutes; the second stage curing temperature is 130°C, and the curing time is 60 minutes; the third stage curing temperature is 150°C, and the curing time is 180 minutes.

[0025] The beneficial effects of the present invention are embodied in:

[0026] (1) The present invention adopts flip chip technology to achieve gold wire-free COB packaging, thereby effectively avoiding the risk of product failure caused by breakage of conventional COB gold wires, and significantly improving product reliability;

[0027] (2) The present invention adopts the eutectic process to realize the mounting of flip chips. Compared with the traditional die bonding and wire bonding process, the manufacturing process is simpler and the production efficiency is higher;

[0028] (3) At the same time, the present invention has the characteristics of adjustable color temperature and brightness, which is more in line with the personalized and differentiated needs of customers and has obvious advantages over traditional light sources. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the present invention.

[0030] Figure 2 It is a schematic diagram of the present invention.

[0031] Explanation of the accompanying drawings: 1-power input terminal 1, 2-power input terminal 2, 3-dimming control terminal, 4-dual-channel LED constant current drive module, 5-normal white flip-chip COB unit, 6-warm white flip-chip COB unit, 7-aluminum substrate, 8-dam, 9-chip pad group, 10-flip chip. DETAILED DESCRIPTION

[0032] In order to make the technical solution of the present invention clearer, the present invention is further described below in conjunction with the accompanying drawings. Any equivalent replacement of the technical features of the technical solution of the present invention and any solution derived from conventional reasoning shall fall within the protection scope of the present invention. The fixed connection and fixed setting mentioned in the present invention are all common connection methods in the mechanical field, including welding, bolt and nut connection, and screw connection.

[0033] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0034] Please refer to the attached Figure 1 The present embodiment provides a dimmable flip-chip COB light source, including an aluminum substrate 7, a white flip-chip COB unit 5, a warm white flip-chip COB unit 6, and a control circuit; the control circuit is located in the middle of the aluminum substrate, the control circuit includes a power input terminal, a dimming control terminal 3, and a dual-channel LED constant current drive module 4, the power input terminal includes a power input terminal 1 and a power input terminal 2, the dual-channel LED constant current drive module 4 is respectively connected to the power input terminal 1, the power input terminal 2, the dimming control terminal 3, the white flip-chip COB unit 5, and the warm white flip-chip COB unit 6, the white flip-chip COB unit 5 is connected to the warm white flip-chip COB unit 6, and the white flip-chip COB unit 6 is connected to the dimming control terminal 3. The OB unit and the warm white flip-chip COB unit are both arranged in a ring shape and are located at the periphery of the control circuit. The normal white flip-chip COB unit 5 and the warm white flip-chip COB unit 6 each include a chip pad group 9 and a flip chip 10. The chip pad group 9 is composed of a number of chip pads connected in sequence from head to tail, and the several chip pads are distributed in a ring shape. The several flip chips 10 are connected to the chip pads one by one through the eutectic process. The head ends of the two chip pad groups 9 are respectively connected to the 5th and 6th pins of the dual-channel LED constant current drive module, and the ends of the two chip pad groups 9 are connected to the power input terminal 2. The dimming control terminal 3 is provided with an interface X3 for inputting two dimming signals. The dual-channel LED constant current drive module 4 converts the two dimming control signals into constant current signals and drives the normal white flip-chip COB unit and the warm white flip-chip COB unit 6 to emit light.

[0035] In this embodiment, the power input terminal 1 and the power input terminal 2 are two connectors X2 and X1 with buckles.

[0036] In this embodiment, three circular dams 8 are provided in sequence from the outside to the inside on the periphery of the aluminum substrate 7, and annular areas are formed between adjacent dams. A normal white flip-chip COB unit 5 is provided in one of the annular areas, and a warm white flip-chip COB unit 6 is provided in the other annular area. Moreover, the annular areas between adjacent dams 8 are filled with mixed fluorescent glue to cover the normal white flip-chip COB units and the warm white flip-chip COB units.

[0037] In this embodiment, the dual-channel LED constant current driver module model is the SM2612EN-LED lighting driver chip produced by Shenzhen Mingwei Electronics.

[0038] like Figure 2 As shown, in this embodiment, the control circuit also includes resistors R1, R2, R3, R4, R5, R6, R7, and R8. The power input terminal 2 is respectively connected to one end of the resistors R1 and R7, the positive electrode of the positive white flip-chip COB unit 5, and the positive electrode of the warm white flip-chip COB unit 6. The first port of the dimming control terminal 3 is respectively connected to the resistors R3 and R6, and the second port of the dimming control terminal 3 is respectively connected to the resistors R2 and R4. The 1st, 2nd, 3rd and 4th pins of the dual-channel LED constant current drive module 4 are connected to the resistors R2, R5, R3 and R8 respectively, the 5th pin of the dual-channel LED constant current drive module is connected to the negative pole of the positive white flip-chip COB unit 5, the 6th pin of the dual-channel LED constant current drive module is connected to the negative pole of the warm white flip-chip COB unit 6, and the 8th pin of the dual-channel LED constant current drive module 4 is connected to the resistor R1; the power input terminal 1 is respectively connected to the resistors R4, R5, R6, R7, R8 and the 9th pin of the dual-channel LED constant current drive module 4.

[0039] The working principle of the present invention is as follows: two PWM dimming signals are input through the interface X3, and after impedance matching, they are sent to the dimming signal input end of the dual-channel LED constant current driving module 4. The dual-channel LED constant current driving module dynamically adjusts the current value output to the pure white / warm white flip-chip COB unit according to the input PWM signal, so that the pure white / warm white flip-chip COB unit emits light of different brightness, and finally obtains the required color temperature\brightness after mixing.

[0040] The present invention also provides a method for manufacturing a dimmable flip-chip COB light source, which specifically comprises the following steps:

[0041] Step 1: Take the prefabricated aluminum substrate 7 and evenly spray flux on the chip pad surfaces of the positive white flip-chip COB unit 5 and the warm white flip-chip COB unit 6.

[0042] Step 2: Complete the flip chip 10 eutectic on the fully automatic eutectic machine. Eutectic conditions: eutectic temperature 320-330℃, vacuum degree 10 -3 ~10 -5 Torr.

[0043] Step 3: Take the aluminum substrate 7 that has completed the eutectic, and print solder paste on the pads of the components to be mounted on the top layer of the PCB;

[0044] Step 4: Place the power input terminal 1 connector X2, the power input terminal 2 connector X1, the dimming control terminal interface X3, the dual-channel LED constant current driver module, and the resistors R1, R2, R3, R4, R5, R6, R7, and R8 on the corresponding pads printed with solder paste;

[0045] Step 5: Place the above aluminum substrate into the reflow oven to complete the welding of components and PCB.

[0046] Step 6: Use a dispensing machine with white silicone to make three circular dams 8 with different radii in sequence according to the silk-screen frame on the aluminum substrate 7, and the spacing between adjacent dams is equal.

[0047] Step 7: Place the aluminum substrate in an oven to cure the silicone at a temperature of 130°C for 30 minutes.

[0048] Step 8: Fill the pre-configured pure white fluorescent glue at the pure white flip-chip COB unit 5, and fill the pre-configured warm white fluorescent glue at the warm white flip-chip COB unit 6.

[0049] Step nine: Place the aluminum substrate in an oven and cure the fluorescent glue in sections. The first section has a curing temperature of 100°C and a curing time of 30 minutes; the second section has a curing temperature of 130°C and a curing time of 60 minutes; the third section has a curing temperature of 150°C and a curing time of 180 minutes.

[0050] Step 10: Complete the photoelectric parameter test on the photoelectric testing machine and retain qualified products.

[0051] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A dimmable flip-chip COB light source, characterized in that: The invention comprises an aluminum substrate, a normal white flip-chip COB unit, a warm white flip-chip COB unit and a control circuit; the control circuit is located in the middle of the aluminum substrate, the control circuit comprises a power input terminal, a dimming control terminal and a dual-channel LED constant current drive module, the dual-channel LED constant current drive module is respectively connected to the power input terminal, the dimming control terminal, the normal white flip-chip COB unit and the warm white flip-chip COB unit, the normal white flip-chip COB unit and the warm white flip-chip COB unit are both arranged in a ring shape and are located at the periphery of the control circuit, the normal white flip-chip COB unit and the warm white flip-chip COB unit are evenly divided into The invention specifically comprises a chip pad group and a flip chip distributed in a ring shape, wherein the chip pad group is composed of a plurality of chip pads connected in sequence head to tail, and a plurality of flip chips are connected to the chip pads one by one through a eutectic process, the head ends of the two chip pad groups are connected to a constant current drive module, and the tail ends of the two chip pad groups are connected to a power input end; the dimming control end is provided with an interface for inputting two dimming signals, and the dual-channel LED constant current drive module converts the two dimming control signals into constant current signals and drives the positive white flip-chip COB unit and the warm white flip-chip COB unit to emit light.

2. The dimmable flip-chip COB light source according to claim 1, characterized in that: The power input terminal includes a first power input terminal and a second power input terminal, and the first power input terminal and the second power input terminal are two connectors with buckles.

3. The dimmable flip-chip COB light source according to claim 1, characterized in that: The aluminum substrate is provided with three circular dams from the outside to the inside, and annular areas are formed between adjacent dams. The normal white flip-chip COB unit is arranged in one of the annular areas, and the warm white flip-chip COB unit is arranged in the other annular area. The annular areas between adjacent dams are filled with mixed fluorescent glue to cover the normal white flip-chip COB unit and the warm white flip-chip COB unit.

4. The dimmable flip-chip COB light source according to claim 1, characterized in that: The dual-channel LED constant current driver module model is SM2612EN-LED lighting driver chip.

5. The dimmable flip-chip COB light source according to claim 2, characterized in that: The control circuit also includes resistors R1, R2, R3, R4, R5, R6, R7, and R8. The second power input terminal is respectively connected to one end of the resistors R1 and R7, the positive electrode of the positive white flip-chip COB unit, and the positive electrode of the warm white flip-chip COB unit. The first port of the dimming control terminal is respectively connected to the resistors R3 and R6, and the second port of the dimming control terminal is respectively connected to the resistors R2 and R4; the first, second, third, and fourth pins of the dual-channel LED constant current drive module are respectively connected to the resistors R2, R5, R3, and R8, the fifth pin of the dual-channel LED constant current drive module is connected to the negative electrode of the positive white flip-chip COB unit, the sixth pin of the dual-channel LED constant current drive module is connected to the negative electrode of the warm white flip-chip COB unit, and the eighth pin of the dual-channel LED constant current drive module is connected to the resistor R1; the first power input terminal is respectively connected to the resistors R4, R5, R6, R7, R8 and the ninth pin of the dual-channel LED constant current drive module.

6. The method for manufacturing a dimmable flip-chip COB light source according to claim 1, characterized in that: The specific steps include: Step 1: Take the pre-made aluminum substrate and evenly spray flux on the chip pad surface of the positive white flip-chip COB unit and the warm white flip-chip COB unit; Step 2: Complete flip chip eutectic on a fully automatic eutectic machine; Step 3: Take the aluminum substrate with eutectic completed as above, and print solder paste on the pads of the components to be mounted on the top layer of the PCB; Step 4: Place the power input terminal 1 connector, power input terminal 2 connector, dimming control terminal interface, dual-channel LED constant current driver module, and resistors R1, R2, R3, R4, R5, R6, R7, and R8 on the corresponding pads printed with solder paste; Step 5: Place the aluminum substrate in step 4 into the reflow oven to complete the welding of components and PCB; Step 6: Use a dispensing machine with white silicone to make three circular dams with different radii according to the silk-screen frame on the aluminum substrate; Step 7: Place the aluminum substrate in step 6 into the oven to cure the silicone; Step 8: Fill the pre-configured pure white fluorescent glue at the pure white flip-chip COB unit, and fill the pre-configured warm white fluorescent glue at the warm white flip-chip COB unit; Step 9: Place the aluminum substrate in step 8 into the oven to cure the fluorescent glue in sections; Step 10: Complete the photoelectric parameter test on the photoelectric testing machine and retain qualified products.

7. The method for manufacturing a dimmable flip-chip COB light source according to claim 6, characterized in that: In step 2, the eutectic conditions are as follows: the eutectic temperature is 320-330°C, the vacuum degree is 10 -3 ~10 -5 Torr.

8. The method for manufacturing a dimmable flip-chip COB light source according to claim 6, characterized in that: In step six, the spacing between adjacent dams is equal.

9. The method for manufacturing a dimmable flip-chip COB light source according to claim 6, characterized in that: In the step seven, the curing temperature is 130° C. and the curing time is 30 minutes.

10. The method for manufacturing a dimmable flip-chip COB light source according to claim 6, characterized in that: In step nine, the curing temperature of the first stage is 100° C., and the curing time is 30 minutes; the curing temperature of the second stage is 130° C., and the curing time is 60 minutes; the curing temperature of the third stage is 150° C., and the curing time is 180 minutes.

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