A COB packaged LED light source and preparation method thereof

Abstract

The present invention discloses a method for preparing a COB packaged LED light source, comprising the following steps: providing a substrate, arranging electrodes and LED chips on the substrate, welding the LED chips on the electrodes, the LED chips including substrates, obtaining a first semi-finished product, fixing the first semi-finished product on a grinding machine table, thinning the substrate of the first semi-finished product, the thinned thickness being greater than or equal to 1 / 3 of the original thickness of the substrate, obtaining a second semi-finished product; covering the LED chips of the second semi-finished product with fluorescent glue, obtaining a finished product. The method for preparing a COB packaged LED light source provided by the present invention can reduce the side light emission ratio of a COB packaged LED light source.

Description

Technical Field

[0001] The present invention relates to the technical field of COB packaged LED light source preparation method, and in particular to a COB packaged LED light source and a preparation method thereof. Background Art

[0002] It is well known that the luminous efficiency of LED chips is higher than that of COB packaged LED light sources. In addition to the power density factor, the effective utilization rate of the chip side light is the biggest influencing factor. The side light of the chip lamp beads can be converted into forward light through the side wall slope of the reflective bowl, while the dam of the COB packaged LED light source is too far away from the chip. Most of the side light is lost internally after multiple reflections and attenuation. The shape of the COB packaged LED light source cannot avoid this loss. The only solution is to reduce the side light output rate of the chip itself. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for preparing a COB packaged LED light source, which can reduce the side light emission ratio of the COB packaged LED light source.

[0004] In order to solve the above technical problems, the present invention provides a method for preparing a COB packaged LED light source, comprising the following steps:

[0005] Providing a substrate, arranging electrodes and LED chips on the substrate, the LED chips being welded on the electrodes, the LED chips including a substrate, to obtain a first semi-finished product;

[0006] Fixing the first semi-finished product on a grinding machine table, thinning the substrate of the first semi-finished product to a thickness greater than or equal to 1 / 3 of the original thickness of the substrate, to obtain a second semi-finished product;

[0007] The fluorescent glue is covered on the LED chip of the second semi-finished product to obtain a finished product.

[0008] In one embodiment, fixing the first semi-finished product on a grinding machine table comprises the following steps:

[0009] A carrier is provided, and a plurality of the first semi-finished products are fixed on the carrier by heating and melting wax under vacuum and preset pressure, and then the carrier with the first semi-finished products fixed thereon is fixed on a grinding machine table.

[0010] In one embodiment, the preset pressure is 30Kpa to 150Kpa.

[0011] In one embodiment, the substrate of the first semi-finished product is thinned and then dewaxed and cleaned to obtain a second semi-finished product.

[0012] In one embodiment, in the dewaxing treatment, an organic solvent is used for heating and soaking to achieve dewaxing.

[0013] In one embodiment, the organic solvent is anhydrous ethanol or citric acid;

[0014] The temperature of the heating and soaking is 120°C to 150°C.

[0015] In one embodiment, during the cleaning, anhydrous ethanol is used for rinsing to remove contaminants.

[0016] In one embodiment, thinning the substrate of the first semi-finished product comprises the following steps:

[0017] First, low-speed rotation grinding is adopted. When the substrate of the first semi-finished product is thinned to a first thickness, high-speed rotation grinding is adopted. When the substrate of the first semi-finished product is thinned to a second thickness, medium-speed rotation grinding is adopted.

[0018] In one embodiment, the first thickness is 1 / 6 to 1 / 5 of the original thickness of the substrate, and the second thickness is 1 / 4 to 1 / 3 of the original thickness of the substrate;

[0019] The rotation speed of the low-speed rotation is 10 rpm to 20 rpm, the rotation speed of the medium-speed rotation is 30 rpm to 50 rpm, and the rotation speed of the high-speed rotation is 60 rpm to 80 rpm.

[0020] Correspondingly, the present invention further provides a COB packaged LED light source, and the COB packaged LED light source is prepared by the above-mentioned method for preparing the COB packaged LED light source.

[0021] The implementation of the present invention has the following beneficial effects:

[0022] The preparation method of the COB packaged LED light source provided by the present invention adds a substrate thinning process on the basis of the original COB packaged LED light source preparation method. Since the chip itself has been welded and the chip size becomes very small after being divided, there is no need to worry about fragmentation when thinning the substrate. The thinning thickness can be greater than or equal to 1 / 3 of the original thickness of the substrate, thereby achieving a significant reduction in the overall height of the chip, and ultimately achieving a significant reduction in the side light emission ratio. At the same time, due to the overall grinding and thinning, it not only helps to reduce the amount of fluorescent glue used, reduce the height of the fluorescent glue layer, and improve the thermal conductivity effect. It also helps to improve the consistency of the chip height, thereby improving the consistency of light color. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in further detail below.

[0024] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0025] In the present invention, “preferred” is only used to describe an implementation method or example with better effects, and it should be understood that it does not constitute a limitation on the protection scope of the present invention.

[0026] In the present invention, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0027] In the present invention, reference to a numerical range includes both endpoints of the numerical range unless otherwise specified.

[0028] To solve the above problems, the present invention provides a method for preparing a COB packaged LED light source, comprising the following steps:

[0029] S1. Providing a substrate, arranging electrodes and LED chips on the substrate, soldering the LED chips on the electrodes, and obtaining a first semi-finished product;

[0030] In one embodiment, the length of the substrate is 100 μm to 600 μm; the thickness of the substrate is 10 μm to 100 μm.

[0031] It should be noted that in the existing chip thinning process, the complete uncut substrate is often thinned first, and then the subsequent process is carried out. However, due to the large size of the substrate, it often breaks, resulting in the inability to achieve large-scale thinning. The present invention uses a finished LED chip that has been cut into small sizes, fixes it on a substrate, and then sets an electrode on the substrate. The LED chip is welded on the electrode. The LED chip includes a substrate to obtain a first semi-finished product, and then the subsequent thinning process is carried out. Since the chip itself has been welded and the chip size becomes very small after being divided, there is no need to worry about fragmentation when thinning the substrate, and the thinning thickness can be greatly increased.

[0032] S2, fixing the first semi-finished product on a grinding machine table, thinning the substrate of the first semi-finished product to a thickness greater than or equal to 1 / 3 of the original thickness of the substrate, to obtain a second semi-finished product;

[0033] In one embodiment, fixing the first semi-finished product on a grinding machine table includes the following steps: providing a carrier, fixing a plurality of the first semi-finished products on the carrier by heating and melting wax under vacuum and a preset pressure, and then fixing the carrier with the first semi-finished products fixed on the grinding machine table.

[0034] In one embodiment, the preset pressure is 30Kpa to 150Kpa. Preferably, the preset pressure is 40Kpa to 100Kpa. Within the above range, strong physical impacts can be avoided to cause defects in the substrate, thereby reducing the degree of damage to the finished chip during the thinning process.

[0035] In one embodiment, the substrate of the first semi-finished product is thinned and then dewaxed and cleaned to obtain a second semi-finished product.

[0036] In one embodiment, in the dewaxing treatment, an organic solvent is used for heating and soaking to achieve wax removal. During the dewaxing process, the process of dissolving the wax layer will cause the problem of trace wax adhesion. Therefore, it is necessary to control the type of organic solvent and the heating and soaking temperature. In one embodiment, the organic solvent is anhydrous ethanol or citric acid; the temperature of the heating and soaking is 120°C to 150°C. Preferably, the organic solvent is anhydrous ethanol; the temperature of the heating and soaking is 130°C to 140°C. The use of the above-mentioned organic solvent and heating and soaking temperature can greatly reduce wax contamination and avoid the problem of reduced chip yield due to contamination and operational damage.

[0037] In one embodiment, during the cleaning, anhydrous ethanol is used for rinsing to remove pollutants. It should be noted that the conventional surface cleaning method is to use a nylon soft brush for scrubbing, but during the scrubbing process, particle contamination and particles will scratch the substrate and the LED chip or electrode. Once the integrity of the electrode is destroyed, subsequent degradation results such as PN junction breakdown or increased dark current will be caused. The present invention uses anhydrous ethanol for rinsing, avoiding physical scrubbing, and ensuring that the surface cleanliness meets the process requirements without generating electrode scratches.

[0038] In one embodiment, thinning the substrate of the first semi-finished product comprises the following steps:

[0039] First, low-speed rotation grinding is adopted. When the substrate of the first semi-finished product is thinned to the first thickness, high-speed rotation grinding is adopted. When the substrate of the first semi-finished product is thinned to the second thickness, medium-speed rotation grinding is adopted. In one embodiment, the first thickness is 1 / 6 to 1 / 5 of the original thickness of the substrate, and the second thickness is 1 / 4 to 1 / 3 of the original thickness of the substrate; the rotation speed of the low-speed rotation is 10rpm to 20rpm, the rotation speed of the medium-speed rotation is 30rpm to 50rpm, and the rotation speed of the high-speed rotation is 60rpm to 80rpm. Preferably, the first thickness is 1 / 5 of the original thickness of the substrate, and the second thickness is 1 / 4 of the original thickness of the substrate; the rotation speed of the low-speed rotation is 13rpm to 18rpm, the rotation speed of the medium-speed rotation is 35rpm to 45rpm, and the rotation speed of the high-speed rotation is 65rpm to 75rpm. The present invention adopts a variable speed thinning method during the grinding and thinning process, which can reduce damage to the substrate during the grinding process, optimize the surface quality of the substrate after thinning, and help improve the consistency of chip height, thereby improving the consistency of light color.

[0040] S3, covering the LED chip of the second semi-finished product with fluorescent glue to obtain a finished product;

[0041] The present invention reduces the overall thickness of the semi-finished product during the grinding and thinning process, which helps to reduce the amount of fluorescent glue used and the height of the fluorescent glue layer, thereby improving the thermal conductivity effect.

[0042] In summary, the preparation method of the COB packaged LED light source provided by the present invention adds a substrate thinning process on the basis of the original COB packaged LED light source preparation method. Since the chip itself has been welded and the chip size becomes very small after being divided, there is no need to worry about breakage when thinning the substrate. The thinning thickness can be greater than or equal to 1 / 3 of the original thickness of the substrate, thereby achieving a significant reduction in the overall height of the chip, and ultimately achieving a significant reduction in the side light emission ratio. At the same time, due to the overall grinding and thinning, it not only helps to reduce the amount of fluorescent glue used, reduce the height of the fluorescent glue layer, and improve the thermal conductivity effect. It also helps to improve the consistency of the chip height, thereby improving the consistency of light color.

[0043] The present invention is further described below with specific embodiments:

[0044] Example 1

[0045] This embodiment provides a method for preparing a COB packaged LED light source, comprising the following steps:

[0046] S1. Providing a substrate, arranging electrodes and LED chips on the substrate, soldering the LED chips on the electrodes, and obtaining a first semi-finished product;

[0047] S2, fixing the first semi-finished product on a grinding machine table, thinning the substrate of the first semi-finished product to a thickness equal to half of the original thickness of the substrate, to obtain a second semi-finished product, specifically comprising the following steps:

[0048] S21, providing a carrier, fixing a plurality of the first semi-finished products on the carrier by heating and melting wax under vacuum and a preset pressure of 50 KPa, and then fixing the carrier with the first semi-finished products fixed on a grinding machine table;

[0049] S22, thinning the substrate of the first semi-finished product by firstly adopting a low-speed rotation grinding of 15 rpm, and when the substrate of the first semi-finished product is thinned to 1 / 5 of the original thickness, adopting a high-speed rotation grinding of 70 rpm, and when the substrate of the first semi-finished product is thinned to 1 / 4 of the original thickness, adopting a medium-speed rotation grinding of 40 rpm, until the thinned thickness is equal to 1 / 3 of the original thickness of the substrate;

[0050] S23, using anhydrous ethanol to heat and soak at 130° C. to remove wax, and then using anhydrous ethanol to rinse to remove pollutants.

[0051] S3. Cover the LED chip of the second semi-finished product with fluorescent glue to obtain a finished product.

[0052] Comparative Example 1

[0053] This embodiment provides a method for preparing a COB packaged LED light source, comprising the following steps:

[0054] S1. Providing a substrate, arranging electrodes and LED chips on the substrate, soldering the LED chips on the electrodes, and obtaining a first semi-finished product;

[0055] S2. Cover the LED chip of the first semi-finished product with fluorescent glue to obtain a finished product.

[0056] The luminous efficacy of the COB packaged LED light sources prepared in Example 1 and Comparative Example 1 are compared, and the specific results are shown in Table 1.

[0057] Table 1 Performance comparison results of COB packaged LED light sources prepared in Example 1 and Comparative Example 1

[0058]

[0059]

[0060] It can be seen from the above results that the preparation method of the COB packaged LED light source provided by the present invention adds a substrate thinning process on the basis of the original COB packaged LED light source preparation method. Since the chip itself has been welded and the chip size becomes very small after being divided, there is no need to worry about fragmentation when thinning the substrate. The thinning thickness can be greater than or equal to 1 / 3 of the original thickness of the substrate, thereby achieving a significant reduction in the overall height of the chip, and ultimately achieving a significant reduction in the side light emission ratio. At the same time, due to the overall grinding and thinning, it not only helps to reduce the amount of fluorescent glue used, reduce the height of the fluorescent glue layer, and improve the thermal conductivity effect. It also helps to improve the consistency of the chip height, thereby improving the consistency of light color.

[0061] The above is a preferred embodiment of the invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the invention. These improvements and modifications are also considered to be within the scope of protection of the invention.

Claims

1. A method for preparing a COB packaged LED light source, characterized in that: The following steps are involved: Providing a substrate, arranging electrodes and LED chips on the substrate, the LED chips being welded on the electrodes, the LED chips including a substrate, to obtain a first semi-finished product; Fixing the first semi-finished product on a grinding machine table, thinning the substrate of the first semi-finished product to a thickness greater than or equal to 1 / 3 of the original thickness of the substrate, to obtain a second semi-finished product; Covering the LED chip of the second semi-finished product with fluorescent glue to obtain a finished product; The step of thinning the substrate of the first semi-finished product comprises the following steps: Firstly, low-speed rotation grinding is performed, and when the substrate of the first semi-finished product is thinned to a first thickness, high-speed rotation grinding is performed, and when the substrate of the first semi-finished product is thinned to a second thickness, medium-speed rotation grinding is performed; The first thickness is 1 / 6 to 1 / 5 of the original thickness of the substrate, and the second thickness is 1 / 4 to 1 / 3 of the original thickness of the substrate; The rotation speed of the low-speed rotation is 10 rpm to 20 rpm, the rotation speed of the medium-speed rotation is 30 rpm to 50 rpm, and the rotation speed of the high-speed rotation is 60 rpm to 80 rpm.

2. The method for preparing a COB packaged LED light source according to claim 1, characterized in that: Fixing the first semi-finished product on a grinding machine table comprises the following steps: A carrier is provided, and a plurality of the first semi-finished products are fixed on the carrier by heating and melting wax under vacuum and preset pressure, and then the carrier with the first semi-finished products fixed thereon is fixed on a grinding machine table.

3. The method for preparing a COB packaged LED light source according to claim 2, characterized in that: The preset pressure is 30Kpa~150Kpa.

4. The method for preparing a COB packaged LED light source according to claim 2, characterized in that: The substrate of the first semi-finished product is thinned, dewaxed and cleaned to obtain a second semi-finished product.

5. The method for preparing a COB packaged LED light source according to claim 4, characterized in that: In the dewaxing process, the dewaxing is achieved by heating and soaking with an organic solvent.

6. The method for preparing a COB packaged LED light source according to claim 5, characterized in that: The organic solvent is anhydrous ethanol or citric acid; The temperature of the heating and soaking is 120°C to 150°C.

7. The method for preparing a COB packaged LED light source according to claim 4, characterized in that: During the cleaning, anhydrous ethanol is used for rinsing to remove pollutants.

8. A COB packaged LED light source, characterized in that: The COB packaged LED light source is prepared by the preparation method of the COB packaged LED light source according to any one of claims 1 to 7.

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