Light-emitting device and LED full-color screen

Abstract

The utility model provides a light-emitting device and an LED full-color screen, and the light-emitting device comprises the components of a supporting substrate which is provided with a conductive circuit and a bonding pad on the surface, and is provided with a welding spot on the bonding pad; the red light LED chip, the green light LED chip and the blue light LED chip are formed on the surface of the supporting substrate in a vertical structure; and the black adhesive layer covers the surface of the supporting substrate and at least covers the conductive circuits on the surface of the supporting substrate and the welding spots on the bonding pads. The black adhesive layer is configured to effectively prevent ambient light from directly irradiating lines and welding spots to form light reflection, so that the contrast ratio of the device is improved, and meanwhile, the light emitting brightness of the chip is not lost. The full-color screen is especially suitable for applications with strict requirements on the light-emitting brightness and the contrast ratio, such as a novel through-type full-color screen of an automobile lamp.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, in particular to a light-emitting device and an LED full-color screen. Background Art

[0002] With the development of LED display technology, the requirements for pixel density, contrast and energy saving of display screens are getting higher and higher, which requires continuous innovation of light-emitting devices used in display screens. The devices used for display screens on the market mainly include CHIPLED, TOP LED and COB. Among them, CHIP LED is divided into single pixel and multi-pixel combination. The blue light chip and green light chip used are mainly five-sided sapphire top-mounted chip or flip-chip.

[0003] In order to improve the contrast of the light-emitting device, in the above packaging method, in addition to blackening the substrate or bracket, melanin is usually added to the packaging glue. Although it can improve the contrast, it greatly reduces the light output efficiency of the light-emitting device. Even if the indoor display requirements are met, the corresponding power consumption is also large due to the large number of LEDs per unit area. In some applications with high brightness requirements, such as the new full-color screen of the through-type car taillight, it is even more necessary to solve the problem of balancing the light output brightness and contrast. Utility Model Content

[0004] In order to overcome the above shortcomings, the utility model provides a light-emitting device and an LED full-color screen, which effectively solve the technical problem that the existing light-emitting devices are difficult to balance the light brightness and contrast.

[0005] The technical solution provided by the utility model is:

[0006] In one aspect, the utility model provides a light emitting device, comprising:

[0007] A supporting substrate having a conductive circuit formed on its surface, wherein the conductive circuit includes pads connected to different polarities;

[0008] The red LED chip, green LED chip and blue LED chip are all vertically structured, fixed on a pad of one polarity on the conductive circuit of the support substrate, and welded to a pad of another polarity through a welding wire to form a welding point;

[0009] A black glue layer is formed on the surface of the supporting substrate around the red LED chip, the green LED chip and the blue LED chip, wherein the black glue layer at least covers the conductive circuits on the surface of the supporting substrate and the solder joints formed on the pads, and does not exceed the upper light emitting surface of any of the red LED chip, the green LED chip and the blue LED chip.

[0010] On the other hand, the utility model provides an LED full-color screen, comprising the above-mentioned light-emitting device.

[0011] The light-emitting device and LED full-color screen provided by the utility model are configured with vertically structured red LED chips, green LED chips and blue LED chips, and a black glue layer is formed on the surface of the supporting substrate, thereby improving the contrast of the device without losing the light output brightness of the chip. It is particularly suitable for applications with strict requirements on light output brightness and contrast, such as the new through-type full-color screen for automobile lights. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic top view of an embodiment of the light emitting device of the utility model;

[0013] Figure 2 for Figure 1 A schematic diagram of a chip bonding wire structure when the structure shown is not covered with a black glue layer;

[0014] Figure 3 for Figure 1 Schematic diagram of another chip bonding wire structure when the structure shown is not covered with a black glue layer;

[0015] Figure 4 for Figure 1 The structure shown is a front view after being covered with a black glue layer;

[0016] Figure 5 This is a schematic structural diagram of another embodiment of the light emitting device of the utility model;

[0017] Figure 6 This is a schematic structural diagram of another embodiment of the light emitting device of the utility model.

[0018] Reference numerals:

[0019] 1-support substrate, 2-soldering pad, 3-soldering point, 11-red light ELD chip, 12-green light LED chip, 13-blue light LED chip, 4-black glue layer, 5-transparent protective layer. DETAILED DESCRIPTION

[0020] In order to more clearly illustrate the implementation cases of the utility model or the technical solutions in the prior art, the specific implementation methods of the utility model will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0021] An embodiment of the utility model provides a light-emitting device, comprising: a supporting substrate, a surface of which is formed with a conductive circuit, the conductive circuit comprising solder pads connected to different polarities; a red light LED chip, a green light LED chip and a blue light LED chip, all of which are vertical structures, fixed on a solder pad of one polarity on the conductive circuit of the supporting substrate, and soldered to a solder pad of another polarity through a solder wire to form a solder joint; a black glue layer formed on the surface of the supporting substrate around the red light LED chip, the green light LED chip and the blue light LED chip, the black glue layer at least covering the conductive circuit on the surface of the supporting substrate and the solder joints formed on the solder pad, and not exceeding the upper light-emitting surface of any one of the red light LED chip, the green light LED chip and the blue light LED chip.

[0022] In this embodiment, the support substrate is a base plate of any material with a conductive circuit configured on the surface, such as planar epoxy molding compound (EMC), sheet molding compound (SMC), Al2O3 ceramic, AlN ceramic, metal-based PCB, etc. In order to reduce the cost and complexity of the conductive circuit design, a PCB board can be used as the support substrate, and the conductive circuit configured on its surface is designed according to the control requirements of the light-emitting device, which is not specifically limited here.

[0023] The light emitting device is packaged with a vertically structured red LED chip, a green LED chip and a blue LED chip. The LED chip can be prepared using binary, ternary and quaternary materials of various wavelengths. The supporting substrate can be a Si substrate, a Cu substrate, etc., which are not specifically limited here. For example, in one example, a silicon substrate red LED chip, a silicon substrate green LED chip and a silicon substrate blue LED chip are packaged to obtain an electronic device.

[0024] The black glue layer is prepared by doping a certain amount of black material in the resin glue, and a black opaque glue layer is obtained after mixing. The resin glue used can be any glue with a certain fluidity, such as silicone resin, epoxy resin, polyimide resin, phenolic resin, urea resin, melamine resin, unsaturated polyester resin, etc. The doped black material and the doping ratio can be evenly mixed with the resin glue to achieve the purpose of shielding the wire lines, solder joints and ink on the surface of the supporting substrate. For example, in one example, a black glue layer is prepared by doping a certain amount of carbon black in the epoxy resin glue. For application fields with relatively high contrast requirements, this can be achieved by appropriately increasing the doping ratio of the black material.

[0025] During the packaging process, the red LED chip, green LED chip and blue LED chip are solidified on the pad of one polarity of the conductive circuit on the surface of the supporting substrate, and are simultaneously welded to the pad of the other polarity through welding wires to form solder joints of a certain thickness. Resin glue mixed with black material is injected into the surface of the packaging substrate, and is formed on the entire surface of the supporting substrate by natural flow and then baked into shape. The polarity of the two pads can be determined according to the actual application. Generally speaking, the pad welded by wire bonding is the positive pad, and the pad used to solidify the LED chip is the negative pad. Of course, the pad welded by wire bonding can also be the negative pad, and the pad used to solidify the LED chip can be the positive pad.

[0026] A solder wire is a conductive material, usually made of metal. One end of the solder wire is connected to an electrode of the LED chip, and the other end is connected to a pad on the supporting substrate. The pad is a pre-designed conductive area on the surface of the supporting substrate for soldering the solder wire. When soldering, solder is used as a solder, which is heated to an appropriate temperature to melt and contact the solder wire and pad. After the solder cools, a solid solder joint is formed, which connects the electrode of the LED chip to the pad of the supporting substrate.

[0027] The thickness of the black glue layer is sufficient as long as it can completely cover the conductive circuits on the surface of the supporting substrate and the solder joints on the pads, and does not exceed the upper light-emitting surface of any of the red LED chip, the green LED chip, and the blue LED chip, and does not affect the light emission of the LED chip. The arrangement of the three LED chips is also determined according to the application, and the corresponding wire circuits are formed on the surface of the supporting substrate. In addition, for the packaging method of the light-emitting device, in other embodiments, the LED chips can be first arranged on the surface of the supporting film, and after the black glue layer is formed around the LED chips, they are further solidified on the supporting substrate. That is, the packaging method of the light-emitting device is not specifically limited here.

[0028] The above embodiment is improved to obtain the present embodiment. In the present embodiment, the red LED chip, the green LED chip and the blue LED chip are formed on the surface of the support substrate in a row, and the circuits between the three chips are formed on the surface of the support substrate in a parallel manner. Specifically, Figure 1-Figure 5 As shown ( Figure 2 for Figure 1 A schematic diagram of a chip bonding wire structure when the structure shown is not covered with a black glue layer; Figure 3 for Figure 1 Schematic diagram of another chip bonding wire structure when the structure shown is not covered with a black glue layer; Figure 2 and Figure 3 The LED chip shown is a vertical structure LED chip with different electrode structures. Figure 2The electrodes of the vertical structure LED chip are formed on the upper surface of the chip. Figure 3 The electrodes of the vertical structure LED chip are formed on the side of the chip). The three LED chips arranged on the surface of the support substrate 1 are arranged in the order of red LED chip 11, green LED chip 12 and blue LED chip 13. The three LED chips are solid-chipped on the pads of one polarity on the conductive circuit of the support substrate 1, and are welded to the pads of the other polarity through welding wires to form welding points 3. When welding the wires, welding points 3 of a certain thickness are formed, such as Figure 2 and Figure 3 Generally speaking, the solder joint will be higher than the supporting substrate by a certain distance. Figure 4 As shown, a black glue layer 4 is formed on the surface of the supporting substrate, and the black glue layer 4 at least completely covers the conductive circuit on the surface of the supporting substrate and the solder joints on the surface of the pad. Figure 3 In the embodiment shown, when the chip electrode is formed on the side of the LED chip, the black glue layer will simultaneously cover the solder joints formed on the surface of the LED chip and the solder joints on the surface of the pad on the supporting substrate. In the above embodiment, the N electrodes and P electrodes of the three LED chips are configured in the same manner, that is, the upper surfaces of the three LED chips are all P electrodes or N electrodes. In other embodiments, the electrode configuration of the three LED chips can also be different, such as the positive electrodes of two of the LED chips facing upward or the positive electrode of one of the LED chips facing upward, etc., and the conductive circuit and the pad can be configured accordingly on the surface of the supporting substrate.

[0029] The arrangement of the chips needs to take into account the brightness of each LED chip, and the LED chip with the lowest brightness should be placed in the middle. Figure 5 As shown, the arrangement of the three LED chips may also be a green LED chip 12, a red LED chip 11, and a blue LED chip 13. In this embodiment, the LED chip electrode may be located on the upper surface of the LED chip, and the bonding wire is led out from the upper surface of the LED chip. The chip electrode may also be arranged at other positions such as the side of the LED chip, which can be selected according to actual application requirements.

[0030] The above embodiment is improved to obtain this embodiment. In this embodiment, Figure 6 As shown, the light-emitting device includes, in addition to: a supporting substrate 1, a red light ELD chip 11, a green light LED chip 12, a blue light LED chip 13, and a black glue layer 4, a transparent protective layer 5 covering the supporting substrate and formed on the surface of the red light LED chip, the green light LED chip, and the blue light LED chip.

[0031] In this embodiment, the red LED chip, the green LED chip and the blue LED chip are protected by further forming a transparent protective layer on the surface of the black glue layer (the transparent protective layer exceeds the upper light-emitting surface of the three chips, and the thickness is not specifically limited). The material of the transparent protective layer can be selected from silicone resin, epoxy resin, polyimide resin, phenolic resin, urea resin, melamine resin, unsaturated polyester resin, etc.

[0032] In the above embodiment, the red LED chip, green LED chip and blue LED chip in the light-emitting device are vertical structure chips, so a black glue layer is formed around the LED chip, which does not affect the light brightness of the LED chip, ensuring the normal light emission of the LED chip. At the same time, the black glue layer is covered on the surface of the supporting substrate, and the opaque black glue covers the conductive circuits and solder joints on the surface of the supporting substrate, preventing ambient light from directly irradiating the circuits and solder joints, avoiding these circuits and solder joints from reflecting ambient light, and enhancing the contrast during the chip lighting process, thereby effectively solving the problem of balancing the brightness and contrast of the light-emitting device. In addition, the black glue can also prevent environmental factors such as moisture and dust from eroding the circuits and solder joints, thereby improving the reliability and stability of the product. In addition, the black glue can also fix components to prevent them from being displaced or falling off during use.

[0033] Another embodiment of the utility model is a full-color LED screen, comprising the above-mentioned light-emitting device. The full-color LED screen comprises a plurality of the above-mentioned light-emitting devices arranged according to a certain rule, and the supporting substrate of each light-emitting device is a whole board, and a certain number of RGB chipsets (including the above-mentioned red LED chips, green LED chips and blue LED chips) are packaged on the surface.

[0034] It should be noted that the above embodiments can be freely combined as needed. The above are only preferred implementations of the utility model. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the utility model, and these improvements and modifications should also be regarded as the protection scope of the utility model.

Claims

1. A light emitting device, characterized in that: include: A supporting substrate having a conductive circuit formed on its surface, wherein the conductive circuit includes pads connected to different polarities; The red LED chip, green LED chip and blue LED chip are all vertically structured, fixed on a pad of one polarity on the conductive circuit of the support substrate, and welded to a pad of another polarity through a welding wire to form a welding point; A black glue layer is formed on the surface of the supporting substrate around the red LED chip, the green LED chip and the blue LED chip, wherein the black glue layer at least covers the conductive circuits on the surface of the supporting substrate and the solder joints formed on the pads, and does not extend beyond the upper light emitting surface of any of the red LED chip, the green LED chip and the blue LED chip.

2. The light emitting device according to claim 1, characterized in that: The red LED chip, the green LED chip and the blue LED chip are formed on the surface of the support substrate in a row.

3. The light emitting device according to claim 2, characterized in that: The red LED chip or the green LED chip is arranged in the middle of the three chips.

4. The light emitting device according to any one of claims 1 to 3, characterized in that: The red LED chip, the green LED chip and the blue LED chip are formed on the surface of the supporting substrate in a parallel manner.

5. The light emitting device according to any one of claims 1 to 3, characterized in that: The light emitting device further comprises a transparent protective layer, which covers the supporting substrate and is formed on the surface of the red light LED chip, the green light LED chip and the blue light LED chip.

6. A full-color LED screen, characterized in that: The light emitting device comprises the light emitting device as claimed in any one of claims 1 to 5.

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