CN109994459B - Method and structure for full-color light distribution of high-integration LED chip module - Google Patents

Abstract

The invention discloses a full-color light distribution method and a full-color light distribution structure of a high-integration LED chip module, wherein the chip module has a length and width or a diameter of less than 50mm or an area of less than 2500mm ² Preparing a thick film power bus on a printed board; and preparing a thin film circuit in the light-emitting region; the invention mixes and adheres the LED devices to the design position according to the white, red, green and blue light of the LED chip manufactured by the membrane bonding process; the invention adopts a method of driving different color LED chips by different voltage and current, so that the invention can emit light rays with any color temperature and color coordinate point within the range of 2000K-6000K according to the requirement. More importantly, the invention realizes the same power on the area of only 1/10 of the prior art, and provides an ideal light-emitting device for the spotlight with compact structure.

Description

A method and structure for full-color light distribution of highly integrated LED chip modules

Technical field

The invention relates to an LED device, in particular to a method and structure for full-color light distribution of a highly integrated LED chip module.

Background technique

Existing LED lamps, especially LED lamps with higher power, such as LED spotlights, are used in offices with large areas. Different situations have different requirements for the irradiation light. The color temperature of the light is required to be whiter or whiter. Warmer, and the color temperature of the light can be adjusted according to the user's preferences.

For example, the Chinese invention patent application, application number 200810214411.5, is called: Adjustable color temperature integrated high-power LED medical lighting chip. The technical solution is: The lighting chip applied for this patent can be used for surgical lighting, examination lighting, and overall operating room lighting in medical treatment. Illumination is used as a light source with adjustable color temperature, which mainly includes LED tube cores, substrates, heat sinks, power adapters, and LED drive controllers; LED tube cores of different colors are integrated on a substrate with a circuit board in a certain array, and the substrate Connected to the heat sink; the integrated chip is divided into multiple groups for power supply according to the different colors of the LED tubes. The brightness of LED tube cores of various colors can be adjusted individually, and any color temperature and brightness of the integrated high-power LED chip in the range of 3500K to 6500K can be adjusted through the color mixing ratio of LED tube strings of different colors.

Analysis of the application document shows that the diameter of the LED light chip of this technology should be about 100 mm. Since its LED chip should belong to the wafer bonding process, wafer bonding technology refers to the production and packaging of wafer structures and circuits. They are all performed on a wafer, and after packaging is completed, it is cut to form a single wafer (Chip); due to process limitations, it will be difficult to solve the heat dissipation problem if the size is further reduced.

This kind of larger COB lighting chip cannot be used on smaller spotlights. Therefore, reducing the diameter to less than 50mm is the key to spotlight application.

People expect the advent of a highly integrated, small-sized, high-power, color-temperature-adjustable LED lamp device.

Contents of the invention

In order to solve the heat dissipation problem that is difficult to solve when the diameter of LED lamp chips in the existing technology is further reduced from 100 mm. The present invention adopts die bonding and adopts thick film and thin film hybrid integration technology to greatly reduce the size of the LED lamp chip under the same power.

Die bonding chip means that after the chip structure and circuit are completed on the wafer, it is cut to form a die, and then a single die is packaged. Obviously, die bonding packaging is more efficient and of higher quality.

The present invention adopts the following technical solutions to achieve:

Design a method and structure for full-color light distribution of a highly integrated LED chip module. The structure of the highly integrated LED chip module includes: polytetrafluoroethylene with a length, width or diameter less than 50mm or an area less than 2500mm ² On the printed board, a thick film integrated circuit power bus printed with conductive paste is prepared and sintered to shape;

Preparing a thin film circuit diagram in the form of a conductive film in the light-emitting area surrounded by the power bus;

At the chip position in the film circuit diagram, the LED chips manufactured by the diaphragm bonding process are bonded at the designed position in a mixed arrangement of white LED, red LED, green LED, and blue LED;

There is a gold or aluminum wire bonding connection between the LED chip and the thin film circuit;

A package crystal containing phosphor is poured on the light-emitting area. The thickness of the package crystal is 0.5 mm to 1.5 mm higher than the top surface of the LED chip.

The light-emitting area is a circular area with a diameter of 14 mm, on which white LEDs, red LEDs, green LEDs, and blue LEDs are mixed and packaged, with a total power of 40W.

Or the light-emitting area is a circular area with a diameter of 6 mm, and the total power of white LED, red LED, green LED and blue LED mixed and packaged on it is 15W.

Or the light-emitting area is a circular area with a diameter of 20 mm, and the total power of white LED, red LED, green LED and blue LED mixed and packaged on it is 60W.

Each of the four color LEDs accounts for 1/4.

A method for full-color light distribution of highly integrated LED chip modules to achieve full-color light distribution at any color coordinate. The method includes the following steps:

The first step: On a PTFE printed board with a length, width or diameter less than 50mm or an area less than ^2500mm2 , first use the thick film integrated circuit method to print the power bus with conductive paste, and then sinter and shape it;

Step 2: In the light-emitting area surrounded by the power bus, prepare a conductive film using electroplating or PVD method, and then photoetch the film circuit pattern according to the design pattern;

Step 3: Bond the LED chips manufactured by the diaphragm bonding process at the designed position in a mixed arrangement of white LEDs, red LEDs, green LEDs, and blue LEDs;

Step 4: Bond the LED chip and the thin film circuit with gold or aluminum wire;

Step 5: Pour the encapsulated crystal containing phosphor in the light-emitting area.

As mentioned in the first step, the conductive paste is printed and sintered into the positive electrode of the external power supply, the negative electrode of the red LED, and the negative electrode of the white LED at the four corners of the polytetrafluoroethylene printed board using the thick film integrated circuit method. electrode, green LED positive electrode, green LED negative electrode; blue LED negative electrode and connected to the power bus.

The power bus and the thin film circuit pattern are connected by welding.

Different colors of LED chips are driven with different voltages and currents by adjusting the positive electrode voltage of the external power supply between 30 and 38V; the red LED current is 0 to 0.45A, the white LED current is 0 to 1.2A, and the blue LED current is 0 to 1.2A. The green LED current can be adjusted from 0 to 0.45A.

The light-emitting area is a circular area with a diameter of 14mm, and the total power of white LED, red LED, green LED and blue LED mixed and packaged on it is 40W.

Or the light-emitting area is a circular area with a diameter of 6 mm, and the total power of white LED, red LED, green LED and blue LED mixed and packaged on it is 15W.

Or the light-emitting area is a circular area with a diameter of 20 mm, and the total power of white LED, red LED, green LED and blue LED mixed and packaged on it is 60W.

Compared with the existing technology, the area of the 40W device in the existing technology: diameter 100mm, area = πr ² , is 7850 square millimeters.

If reduced to 28*28 millimeters, the area would be 784 square millimeters, which is only 1/10 of the existing technology.

If reduced to 18*18 millimeters, the area would be 324 square millimeters, which is only 1/20 of the existing technology.

The advantage of the present invention is that: due to the use of thick film and thin film hybrid integration technology and die bonding chips on the polytetrafluoroethylene printed board, red, green and white LED chips are bonded in a mixed arrangement, and different types of LED chips are bonded. The method of driving the color LED chips with different voltages allows the LED chip of the present invention to emit light with any color temperature and brightness at any color coordinate within the range of 2000K to 6500K as needed. The packaged crystal containing phosphor will better convert the various colors of LED chips. The light is mixed, and the emitted light is more even and soft. More importantly, the present invention achieves the same power in only about 1/10 to 1/20 of the area of the prior art, providing an ideal light-emitting device for compact spotlights.

Description of the drawings

Figure 1 is a schematic plan view of Embodiment 1 of a full-color light distribution method and structure of a highly integrated LED chip module according to the present invention; the back of the substrate 1 in the figure is a heat sink, and the long side 2 of Embodiment 1 is 28mm, width 3 is 28mm;

Figure 2 is a schematic diagram of a method and structure for full-color light distribution of a highly integrated LED chip module according to the present invention, encapsulating a packaging crystal 9 containing phosphor.

Figure 3 is a schematic diagram of a large-sized prior art COB lighting chip. The ordinary substrate 21 is arranged within the frame 20. External heat dissipation fins 23 are required outside the frame 20. The distance between ordinary chips 22 is relatively large, so There are nine 8W ordinary chips installed inside.

Figure 4 is a schematic diagram of another large-sized prior art COB lighting chip. The circular ordinary substrate 30 has a diameter of 100 mm, and 40 1W low-power ordinary chips 31 are distributed on it.

Detailed ways

The present invention will be described below in conjunction with specific embodiments.

Example 1:

As shown in Figures 1 and 2, the structure of a highly integrated LED chip module is designed, including:

On a ^{polytetrafluoroethylene} printed board 5 with a length, width or diameter less than 50mm or an area less than 2500mm, prepare a thick film integrated circuit power bus printed with conductive paste, and sinter and shape it;

Prepare a thin film circuit diagram in the form of a conductive film in the light-emitting area 4 surrounded by the power bus;

At the chip position in the film circuit diagram, the LED chips manufactured by the diaphragm bonding process are bonded at the designed position in a mixed arrangement of white LED62, red LED61, green LED63, and blue LED64;

There is a gold or aluminum wire bonding connection between the LED chip and the thin film circuit;

A package crystal 9 containing phosphor is poured on the light-emitting area 4. The thickness of the package crystal 9 is 0.5 mm to 1.5 mm higher than the top surface of the LED chip.

In the first embodiment, the light-emitting area 4 is a circular area with a diameter of 14 mm, on which the white LED 62, the red LED 61, the green LED 63, and the blue LED 64 are mixed and packaged with a total power of 40W.

In the second embodiment, the light-emitting area 4 is a circular area with a diameter of 6 mm, on which the white LED 62, the red LED 61, the green LED 63, and the blue LED 64 are mixed and packaged with a total power of 15W.

In the third embodiment, the light-emitting area 4 is a circular area with a diameter of 20 mm, on which the white LED 62, the red LED 61, the green LED 63, and the blue LED 64 are mixed and packaged with a total power of 60W.

A method for realizing full-color light distribution of the above-mentioned highly integrated LED chip module, the method includes the following steps:

The first step: On the PTFE printed board 5 whose length, width or diameter is less than 50mm or the area is less than ^2500mm2 , first use the thick film integrated circuit method to print the power bus with conductive paste, and then sinter and shape it. ;

Step 2: In the light-emitting area 4 surrounded by the power bus, prepare a conductive film by electroplating or PVD method, and then photoetch the film circuit pattern according to the design pattern;

Step 3: Bond the LED chips manufactured by the diaphragm bonding process at the designed position in a mixed arrangement of white LED62, red LED61, green LED63, and blue LED64;

Step 4: Bond the LED chip and the thin film circuit with gold or aluminum wire;

Step 5: Pour the package crystal 9 containing phosphor in the light-emitting area 4.

As mentioned in the first step, the conductive paste is printed and sintered into the external power supply positive electrode 7, the red LED negative electrode 82, and the four corners of the polytetrafluoroethylene printed board 5 using the thick film integrated circuit method. The white LED negative electrode 84; the blue LED negative electrode 83; the green LED negative electrode 85 are connected to the power bus.

The power bus and the thin film circuit pattern are connected by welding.

Different colors of LED chips are driven with different voltages and currents by adjusting the voltage of the positive electrode 7 of the external power supply between 30 and 38V; the red LED current is 0 to 0.45A, the white LED current is 0 to 1.2A, and the blue LED current is 0 to 1.2A. , the green LED current is adjusted between 0~0.45A.

As shown in Figure 1:

In the first embodiment, the light-emitting area 4 is a circular area with a diameter of 14 mm, on which the white LED 62, the red LED 61, the green LED 63, and the blue LED are mixed and packaged with a total power of 40W.

In the second embodiment, the light-emitting area 4 is a circular area with a diameter of 6 mm, and the total power of the white LED 62, the red LED 61, the green LED 63 and the blue LED mixed and packaged thereon is 15W.

In the third embodiment, the light-emitting area 4 is a circular area with a diameter of 20 mm, on which the white LED 62, the red LED 61, the green LED 63, and the blue LED are mixed and packaged with a total power of 60W.

As shown in Figure 1: Die bonding packaging can also improve the cleanliness of LED device production, prevent the dicing and slicing process before bonding from damaging the device structure, and improve the packaging yield and reliability. Therefore, it is a kind of An effective means to reduce packaging costs.

Hybrid integration technology can integrate a large number of circuit chips and small passive components on a very small substrate area.

If the standard SMT surface mount technology is used, it will inevitably occupy an area 10 to 20 times higher than that of hybrid integration technology.

Fluoroplastics (polytetrafluoroethylene) have high resistance characteristics in high-temperature environments. Polyurethane resins can adapt to particularly large temperature changes. For example, automotive electronics require extremely small thermal expansion coefficients under very high temperature conditions. At this time, fluoroplastics are most capable.

Usually, the conductor material used in COB printed boards is copper-based conductors, and the bonding pad needs to be surface treated. The copper base material is plated with 2 to 4 μm nickel, and then 0.1 to 0.2 μm gold (CuNiAu) is plated.

Use silver-containing epoxy conductive adhesive to bond the chip to the printed board mounting position and cure at 250°C. The heat dissipation problem of power devices is to form a heat path through the back of the chip and the copper layer of the bonded printed circuit board. During final assembly, the cooling plate is fixedly installed on the heat dissipation finger or package.

The circuit connection between the chip and the printed board uses aluminum or gold wire. The biggest advantage of aluminum wire bonding is that the bonding can be performed at room temperature. Aluminum wire ultrasonic bonding shows high reliability when products are subjected to high temperatures or large temperature changes. To achieve bonding reliability, gold wire requires a bonding temperature above 120°C.

Aluminum wire ultrasonic bonding is actually a grinding and sassafrasing welding process. Under a preset pressure, the ultrasonic vibration generated by the ultrasonic transducer presses and grinds two pure metals against each other until the grinding and sassafrasing bonding is completed.

The amplitude of ultrasonic vibration is 1 to 2 μm.

The coordinates of various white lights on the color coordinate diagram:

6500K daylight color X.313 Y.337

5000K Neutral White X.346 Y.359

4000K cool white X.380 Y.380

3500K white X.409 Y.394

3000K warm white X.440 Y.403

Through calculations and experiments, LED chips of different colors are driven with different voltages and currents to achieve color temperature adjustment.

The above contents are only the preferred embodiments of the present invention. For those of ordinary skill in the art, there will be changes in the specific implementation modes and application scope according to the ideas of the present invention. The contents of this description should not be understood as limiting the scope of the present invention. limits.

Claims (6)

1. A method for full-color light distribution of highly integrated LED chip modules, characterized in that: the method includes the following steps: Step 1: On the PTFE printed board (5) whose length, width or diameter is less than 50mm or the area is less than ^2500mm2 , first use the thick film integrated circuit method to print the power bus with conductive paste, and then sintering and shaping; Step 2: In the light-emitting area (4) surrounded by the power bus, prepare a conductive film using electroplating or PVD method, and then photoetch the film circuit pattern according to the design pattern; Step 3: Bond the LED chips manufactured by the diaphragm bonding process at the designed position in a mixed arrangement of white LED (62), red LED (61), green LED (63), and blue LED (64); Step 4: Bond the LED chip and the thin film circuit with gold or aluminum wire; Step 5: Pour the encapsulated crystal (9) containing phosphor in the light-emitting area (4). 2. The method for full-color light distribution of highly integrated LED chip modules according to claim 1, characterized in that: as described in the first step, sintering and shaping are also carried out on the polytetrafluoroethylene printed board (5) At the four corners, use the thick film integrated circuit method to print and sinter the conductive paste into the positive electrode of the external power supply (7), the negative electrode of the red LED (82), the negative electrode of the white LED (84), the negative electrode of the blue LED (83), the green The negative electrode of the light LED (85) is connected to the power bus; By using a method of driving LED chips of different colors with different voltages and currents, the present invention can emit light at any color temperature and color coordinate point within the range of 2000K to 6000K as needed. 3. The method for full-color light distribution of highly integrated LED chip modules according to claim 2, characterized in that: the method of driving LED chips of different colors with different voltages and currents is to connect the positive electrode of the external power supply (7) The voltage can be adjusted from 30 to 38V; the red LED current can be adjusted from 0 to 0.45A, the white LED current can be adjusted from 0 to 1.2A, the blue LED current can be adjusted from 0 to 1.2A, and the green LED current can be adjusted from 0 to 0.45A. 4. The method for full-color light distribution of highly integrated LED chip modules according to claim 1, characterized in that: the light-emitting area (4) is a circular area with a diameter of 14 mm, on which white light LEDs are mixed and packaged (62), red LED (61), green LED (63), and blue LED (64) with a total power of 40W. 5. The method for full-color light distribution of highly integrated LED chip modules according to claim 1, characterized in that: the light-emitting area (4) is a circular area with a diameter of 6 mm, on which white light LEDs are mixed and packaged (62), red LED (61), green LED (63) and blue LED (64) with a total power of 15W. 6. The method for full-color light distribution of highly integrated LED chip modules according to claim 1, characterized in that: the light-emitting area (4) is a circular area with a diameter of 20 mm, on which white light LEDs are mixed and packaged (62), red LED (61), green LED (63), and blue LED (64) with a total power of 60W.