Mini COB module and manufacturing method thereof

Abstract

The present application relates to a kind of Mini COB module and its manufacturing method, in the method by making lens, and the lens has cavity inside, lens cover is set on light emitting chip, so that light emitting chip is located in cavity.By the production of the manufacturing method of the present application, the light emitted by light emitting chip passes through lens, can realize large-angle light emitting.The lens produced by the manufacturing method of the present application can be realized by mold forming its hollow design, i.e.the lens has cavity inside, then lens is attached to circuit board above, compared with the conventional mini COB manufacturing method, the spot of single light emitting chip in the mini COB produced by the above-mentioned mode is larger, so that the distance between chip on circuit board can be increased, the amount of light emitting chip and glue is reduced, and cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of Mini COB modules, in particular to a Mini COB module and a manufacturing method thereof. BACKGROUND

[0002] Mini COB modules are micro LED display modules using chip on board (COB) technology.

[0003] Most existing Mini COB modules usually use glue to cover the circuit board of the Mini COB module, and then a point ball lens is arranged at the position of the light-emitting chip. In order to have a larger brightness range, the existing Mini COB module needs to design a smaller spacing between two adjacent light-emitting chips, which requires a large number of light-emitting chips and glue, resulting in a large amount of raw materials and increased production costs. At the same time, too small spacing between two adjacent light-emitting chips will cause too many lines on the circuit board, increasing the design difficulty. SUMMARY

[0004] Therefore, it is necessary to provide a Mini COB module and a manufacturing method thereof.

[0005] The technical solution of the present application to solve the above technical problems is as follows: a Mini COB module manufacturing method, comprising:

[0006] A carrier plate is provided, the surface of the carrier plate is processed to form a convex block, and a mold is obtained;

[0007] A release material is coated on the convex block of the mold to obtain a release layer;

[0008] Transparent glue is sprayed on the release layer on the surface of the mold to obtain a transparent glue layer;

[0009] After the transparent glue layer is heat-cured, it is demolded from the mold to obtain a lens with a cavity;

[0010] Solder paste is brushed on a circuit board, a light-emitting chip is placed on the solder paste, and the light-emitting chip is fixed on the circuit board by soldering with the solder paste to obtain a first COB lamp plate;

[0011] Adhesive is applied around the light-emitting chip on the first COB lamp plate to obtain a second COB lamp plate;

[0012] The lens is connected with the second COB lamp plate through the adhesive, the light emitting chip on the second COB lamp plate is located in the cavity of the lens, and a third COB lamp plate is obtained.

[0013] The third COB lamp plate is placed into a back plate, and an optical film is combined to cover the back plate, so that a Mini COB module is obtained.

[0014] In one embodiment, the carrier plate is any one of a copper plate, an aluminum alloy plate and a steel plate.

[0015] In one embodiment, in the step of providing the carrier plate and processing the surface of the carrier plate to form convex blocks to obtain a mold,

[0016] The surface of the carrier plate is processed by a numerical control machine tool to form convex blocks to obtain a mold.

[0017] In one embodiment, the material of the release layer is a mold release agent or a release film.

[0018] In one embodiment, in the step of spraying transparent glue on the release layer on the surface of the mold to obtain a transparent glue layer,

[0019] The transparent glue is sprayed onto the mold by a piezoelectric valve jet dispensing machine or a screw type dispensing machine.

[0020] In one embodiment, the viscosity of the transparent glue is 7000-40000 mPa·s.

[0021] In one embodiment, the thixotropy coefficient of the transparent glue is equal to the thixotropy coefficient of the silicone glue 4-6 (1S -1 / 10S -1 ).

[0022] In one embodiment, in the step of brushing printed solder paste on the circuit board, placing a light emitting chip on the printed solder paste, and fixing the light emitting chip on the circuit board by welding to obtain a first COB lamp plate,

[0023] The light emitting chip is placed upside down on the printed solder paste.

[0024] In one embodiment, in the step of coating adhesive around the light emitting chip on the first COB lamp plate to obtain a second COB lamp plate,

[0025] The adhesive is spot-coated around the light emitting chip on the first COB lamp plate by a piezoelectric valve jet dispensing machine or a screw type dispensing machine.

[0026] A Mini COB module comprises a circuit board, a plurality of light emitting chips, a plurality of lenses, a back plate and an optical film combination; the back plate has a recess, the circuit board is arranged at the bottom of the recess, the light emitting chips are arranged on the circuit board in a flip-chip manner, and each light emitting chip is provided with a lens, the lens has a cavity, each lens covers a light emitting chip, the light emitting chip is located in the cavity, the lens is connected with the circuit board through an adhesive layer, and the optical film combination is arranged on the back plate and used for sealing the recess.

[0027] The Mini COB module manufacturing method provided by the application has the following beneficial effects: in the method, a lens is manufactured, the lens has a cavity inside, the lens covers a light emitting chip, and the light emitting chip is located in the cavity. The Mini COB module manufactured by the manufacturing method has the following advantages: the light emitted by the light emitting chip can be emitted at a large angle through the lens. The lens manufactured by the manufacturing method is formed by a mold and has a hollow design inside, that is, the lens has a cavity inside, and then the lens is attached to the circuit board. Compared with the conventional Mini COB manufacturing method, the light spot of each light emitting chip in the manufactured Mini COB is larger, the distance between the chips on the circuit board is increased, the amount of light emitting chips and glue is reduced, and the cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the application, and therefore should not be regarded as a limitation to the scope. Other related drawings can also be obtained by those skilled in the art without creative labor.

[0029] Figure 1 It is a flowchart of a Mini COB module manufacturing method of an embodiment;

[0030] Figure 2 It is a schematic diagram of the plane structure of the mold in one direction of an embodiment;

[0031] Figure 3 It is a schematic diagram of the plane structure of the mold and the lens in one direction of an embodiment;

[0032] Figure 4 It is a schematic diagram of the plane structure of the third COB lamp plate in one direction of an embodiment;

[0033] Figure 5 It is a light emitting brightness condition diagram of a single light emitting chip in a lens of an embodiment;

[0034] Figure 6 Light intensity of a single light emitting chip at different angles of the lens for an embodiment;

[0035] Figure 7 Light intensity of a single light emitting chip at different radii of the lens for an embodiment;

[0036] Figure 8 Light intensity of a single light emitting chip at different color coordinates for an embodiment;

[0037] Figure 9 Light intensity of a single light emitting chip at different radial angles of the lens for an embodiment;

[0038] Figure 10 A schematic diagram of a planar structure of a Mini COB module in one direction for an embodiment;

[0039] Figure 11 A schematic diagram of a partial enlarged structure of the A part in the middle. Figure 10

[0040] In the drawings, 20, mold; 210, carrier plate; 220, convex block; 230, lens; 231, cavity; 240, third COB lamp plate; 250, light emitting chip; 260, circuit board; 30, Mini COB module; 310, back plate; 320, optical film combination; 330, groove. DETAILED DESCRIPTION

[0041] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the present application can be more thoroughly and completely understood.

[0042] It should be noted that when an element is referred to as being "fixed" to another element, it can be directly on the other element or there can be an intervening element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or there can be an intervening element. The terms "vertical", "horizontal", "left", "right", and similar expressions used herein are for illustrative purposes only and are not intended to be limiting.

[0043] ​Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0044] In one embodiment, such as Figure 1 As shown, a method for creating a Mini COB module includes the following steps:

[0045] Step 110: Provide a carrier plate, process the surface of the carrier plate to form a convex block, and obtain a mold.

[0046] The mold 20 obtained by the above steps is as follows Figure 2 As shown. It should be noted that the convex block 220 is obtained by machining the surface of the carrier plate 210. The shape of the convex block 220 is made according to the cavity shape of the lens to be produced later. The shape of the lens cavity will affect the angle at which the light-emitting chip emits light inside the lens. Therefore, in this step, the convex block 220 on the mold 20 can be machined into any desired shape as needed. The shape of the convex block 220 is usually hemispherical, and lenses made from hemispherical convex blocks 220 of different heights and curvatures will affect the light emitted.

[0047] In one embodiment, the carrier plate 210 is any one of a copper plate, an aluminum alloy plate, and a steel plate. Specifically, the copper plate has good ductility, so its surface can be more easily processed to produce protrusions 220. The aluminum alloy plate has good casting and plastic processing properties, and can be more easily processed into any shape. The steel plate has higher structural strength, and the protrusions 220 processed on its surface are less likely to break.

[0048] In one embodiment, a CNC machine tool is used to process the surface of the carrier plate 210 to form a convex block 220, thus obtaining the mold 20. Specifically, since the convex block 220 is relatively small, and CNC machine tools effectively solve the problem of processing complex, precise, small-batch, and multi-variety parts, a CNC machine tool is chosen to process the surface of the carrier plate 210. The CNC machine tool can accurately and quickly process the convex block 220 on the surface of the carrier plate 210. Simultaneously, the CNC machine tool can more precisely process the hemispherical convex block 220, and precisely carve the height and curvature of the hemispherical convex block 220.

[0049] Step 120: Apply release material to the convex block of the mold to obtain a release layer.

[0050] It is to be noted that the release layer is attached to the surface of the convex block and around the convex block on the mold. The release layer is used to facilitate the demolding of the lens from the mold.

[0051] In an embodiment, the material of the release layer is a mold release agent or a release film. Specifically, the mold release agent, also known as a demolding agent, is a functional substance applied between the mold and the product, which is designed to prevent the molded composite product from sticking to the mold, so that the product can be easily demolded from the mold, while ensuring the surface quality of the product and the integrity of the mold. In this embodiment, the mold release agent is an oily mold release agent or a water-based mold release agent. The oily mold release agent is made of high-load, extreme-pressure-resistant, and high-wear-resistant composite raw materials. The finished product has good surface finish and is not greasy. It has the advantages of good effect, multiple demolding times, rust prevention, lubrication, no damage to the mold, and increased silicone surface finish. The water-based mold release agent is environmentally friendly, non-toxic, and odorless, harmless to the human body, and easy to clean without polluting the mold and product surface.

[0052] Step 130: Spraying transparent glue on the release layer on the surface of the mold to obtain a transparent glue layer.

[0053] In an embodiment, the transparent glue is sprayed onto the mold by using a piezoelectric valve jet dispensing machine or a screw type dispensing machine.

[0054] In this embodiment, the piezoelectric valve jet dispensing machine is a high-precision dispensing equipment that uses the deformation of piezoelectric ceramic to control the glue flow and the accurate position of dispensing. The piezoelectric valve jet dispensing machine is mainly based on the characteristics of piezoelectric ceramic. The piezoelectric ceramic valve is the core component, which controls the opening and closing of the valve through the change of voltage, thereby controlling the flow of glue and the position of dispensing. The control system is responsible for accurately controlling the opening and closing time of the valve and the flow of glue to ensure the accuracy of dispensing. The dispensing head is responsible for dispensing glue at the designated position. Therefore, by using the piezoelectric valve jet dispensing machine, the transparent glue can be uniformly sprayed on the release layer, and the amount of transparent glue sprayed is appropriate, which can completely cover the convex block of the mold.

[0055] In the embodiment, the screw type glue dispenser is an automatic glue dispensing equipment which extracts glue from a glue barrel and delivers it to a glue dispensing head through the rotary motion of a screw, and then dispenses the glue on the position where glue is needed through the motion of the glue dispensing head. The screw type glue dispenser mainly involves the rotary motion of the screw and the motion of the glue dispensing head, and the specific process of glue dispensing is as follows: first, glue is filled into the screw pump, and the screw is rotated by the motor. Then, the screw rotation sucks the glue from the feed pipe and delivers it to the nozzle through the action of compressed air or electromagnetic valve. Next, through the adjustment of the control system, the nozzle and needle can move according to the set trajectory, and the glue is sprayed to the area where it is needed to be coated. Finally, after the glue dispensing is completed, the equipment is automatically cleaned, preparing for the next work. The screw type glue dispenser has the following characteristics: 1. High precision: the screw type glue dispenser adopts precise screw transmission, which can realize high-precision glue dispensing operation and improve product quality. 2. Wide application range: suitable for various glues and fluids, different glues and coating methods can be selected according to different needs. 3. High efficiency and stability: the high-efficiency glue supply system ensures stable glue supply and improves production efficiency. 4. Simple operation: simple structure, easy to operate and easy to use. 5. Programmable control: the glue dispensing trajectory and parameters can be controlled through programming to realize automatic production. 6. Easy maintenance: simple structure, easy to disassemble and clean, convenient for maintenance. 7. High reliability: high-quality parts and materials are used, with high reliability, and can run stably for a long time. Therefore, by using the screw type glue dispenser to spray transparent glue on the release layer, the transparent glue can be uniformly coated on the release layer, and the amount of sprayed transparent glue is appropriate, which can completely cover the convex blocks of the mold.

[0056] In an embodiment, the viscosity of the transparent glue is 7000-40000 mPa·s. Specifically, the transparent glue with a viscosity of 7000-40000 mPa·s can ensure that the transparent glue can be firmly adsorbed on the convex blocks of the mold, and it is convenient for the transparent glue to be solidified and molded subsequently.

[0057] In an embodiment, the thixotropy coefficient of the transparent glue is equal to the thixotropy coefficient of the silica gel, which is 4-6 (1S -1 / 10S -1 ). Specifically, the thixotropy coefficient of the glue, also known as the thixotropy index of the glue, is a parameter reflecting the degree of change of the viscosity of a fluid material when it is subjected to shear force. In the embodiment, the thixotropy coefficient of the silica gel is 4-6 (1S -1 / 10S -1) refers to the degree of viscosity change of the silica gel in the process of changing the shear rate from 1 S to 10 S, which is between 4 and 6. The transparent glue with the above degree of thixotropy coefficient can better flow from the glue dispenser to the convex block and better adhere to the convex block, thereby better forming the lens.

[0058] Step 140, after the transparent glue layer is heat-cured, it is demolded from the mold to obtain a lens with a cavity.

[0059] The lens 230 obtained by the above steps is as shown in Figure 3 It should be noted that the transparent glue layer forms the lens 230 after complete curing, and the lens 230 is a transparent lens 230. The internal cavity 231 of the lens 230 is the same in shape and size as the convex block 220 on the carrier plate 210 of the mold 20.

[0060] Step 150, tin paste is brushed on the circuit board, the light-emitting chip is placed on the tin paste, and the light-emitting chip is fixed on the circuit board by soldering with the tin paste to obtain a first COB lamp plate.

[0061] In an embodiment, the light-emitting chip is placed upside down on the tin paste. Specifically, by placing the light-emitting chip upside down on the tin paste, the light-emitting chip can be placed upside down on the circuit board after soldering. Through the above arrangement, when the lens covers the light-emitting chip, the light spot of the light-emitting chip can be increased when it emits light, i.e., the light-emitting area of each light-emitting chip is increased, thereby increasing the spacing between each light-emitting chip on the circuit board and ensuring uniform light emission of the Mini COB module.

[0062] In an embodiment, the material of the circuit board is any one of glass, aluminum substrate, BT (Bismaleimide Triazine) board, and FR4 epoxy glass cloth laminated board.

[0063] Step 160, the adhesive is applied around the light-emitting chip on the first COB lamp plate to obtain a second COB lamp plate.

[0064] In an embodiment, the adhesive is applied around the light-emitting chip on the first COB lamp plate by a piezoelectric valve jet dispenser or a screw type dispenser. The piezoelectric valve jet dispenser or the screw type dispenser can quickly and uniformly apply the adhesive to the first COB lamp plate.

[0065] Step 170, connecting the lens to the second COB lamp plate through the adhesive, the light emitting chip on the second COB lamp plate is located in the cavity of the lens, obtaining a third COB lamp plate.

[0066] The third COB lamp plate 240 obtained by the above steps is shown in Figure 4 . It should be noted that the lens 230 is placed on the adhesive, and after the adhesive cools to form an adhesive layer, the lens 230 can be fixed on the circuit board 260. At this time, the lens 230 covers the light emitting chip 250, and the light emitting chip 250 is located in the cavity 231 of the lens 230, thereby obtaining the third COB lamp plate 240.

[0067] Step 180, placing the third COB lamp plate into the back plate, and covering the back plate with an optical film combination, obtaining a Mini COB module.

[0068] It should be noted that the optical film combination is completely sealed on the back plate, which can prevent light leakage between the back plate and the optical film combination. The optical film combination is composed of various optical films, such as diffusion film, brightness enhancement film, lens film, and composite film. In this embodiment, the optical film combination is composed of diffusion film and brightness enhancement film. By providing the optical film combination on the back plate, the luminous brightness of the Mini COB module can be further increased, and the uniformity of the light emission can be improved.

[0069] In one embodiment, as shown in Figure 5 , Figure 6 , Figure 7 , Figure 8 and Figure 9 , through the above Mini COB module manufacturing method, the luminous intensity of a single light emitting chip under various conditions is obtained in the Mini COB module manufactured. Figure 6 It can be seen that the luminous brightness of the light emitting chip is larger when the lens spherical angle is between 60°-80°. Through Figure 7 , it can be seen that the luminous brightness of a single light emitting chip under different radii of the lens. Through Figure 8 , it can be seen that the luminous brightness of a single light emitting chip under different color coordinates. Through Figure 9 , it can be seen that the luminous brightness of a single light emitting chip under different radial angles of the lens. The specific light emitting conditions of a single light emitting chip are shown in Table 1.

[0070] Table 1 Comparison table of light emitting conditions of light emitting chip

[0071]

[0072]

[0073] In the above table, Phi represents the azimuth angle for describing the inclination angle of the light relative to the plane where the light emitting chip is located. As shown in No. 1 of the table, Phi is 0, which means the azimuth angle is 0°, and at this time, the azimuth represented by Phi is parallel to the plane where the light emitting chip is located. θ represents the angle between the measuring point and Phi. As shown in No. 1 of the table, Phi is 0 and θ is -90°, and at this time, the angle between the measuring point and the plane where the light emitting chip is located is -90°. As can be seen from the above table, the light emitting brightness of each light emitting chip in the Mini COB module made by the Mini COB module manufacturing method is uniform and the light spot is large, so in the entire Mini COB module, there is no need to use too many light emitting chips and glue, thereby reducing the cost.

[0074] In one embodiment, as shown in Figure 10 and Figure 11 A Mini COB module 30 includes a circuit board 260, a plurality of light emitting chips 250, a plurality of lenses 230, a back plate 310 and an optical film combination 320. The back plate 310 has a recess 330, the circuit board 260 is arranged at the bottom of the recess 330, the light emitting chips 250 are flip-chip arranged on the circuit board 260, and each light emitting chip 250 is provided with a lens 230, the lens 230 has a cavity 231, each lens 230 covers a light emitting chip 250, the light emitting chip 250 is located in the cavity 231, the lens 230 is connected with the circuit board 260 through an adhesive layer, and the optical film combination 320 is arranged on the back plate 310, and the optical film combination 320 is used for sealing the recess 330.

[0075] Specifically, the Mini COB module 30 is used to provide light brightness for LED lighting tubes, panel lights, special lighting, light box lights, television backlights, etc. The light emitting chip 250 in the Mini COB module 30 is flip-chip mounted on the circuit board 260, and the lens 230 is arranged on the light emitting chip 250. Therefore, the light emitted by the light emitting chip 250 can be refracted after passing through the lens 230, so that the light spot of a single light emitting chip 250 is larger. Therefore, the light emitting chip 250 inside the Mini COB module 30 uses fewer light emitting chips 250 and glue compared to the traditional Mini COB module 30, thereby saving costs. Moreover, different sizes and shapes of lenses 230 can be produced according to requirements, and the angles of light refracted by different lenses 230 are different. Therefore, the manufacturing method of the Mini COB module 30 can produce Mini COB modules 30 with different light emitting brightness and uniformity according to different requirements. Meanwhile, in the present application, the recess 330 on the back plate 310 is sealed by the optical film combination 320, which can further increase the light emitting brightness of the Mini COB module 30 and improve the uniformity of light emission. Moreover, the optical film combination 320 is closely attached to the back plate 310, preventing light leakage between the back plate 310 and the optical film combination 320.

[0076] In one embodiment, each of the light emitting chips 250 is arranged in a matrix on the circuit board 260. Specifically, the distances between each of the light emitting chips 250 are equal, and arranged in a matrix. By arranging in this way, the light emitted by the Mini COB module 30 is uniform.

[0077] Each of the technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present application.

[0078] The above embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of the patent of the present application should be subject to the appended claims.

Claims

1. A manufacturing method of a Mini COB module, characterized in that, The application relates to a Mini COB module and a manufacturing method thereof. A carrier plate is provided, the surface of the carrier plate is processed to form convex blocks, and a mold is obtained; A release material is coated on the convex blocks of the mold to obtain a release layer; Transparent glue is sprayed on the release layer on the surface of the mold to obtain a transparent glue layer; After the transparent glue layer is heat-cured, the transparent glue layer is demolded from the mold to obtain a lens with a cavity; Solder paste is brushed on a circuit board, a light-emitting chip is placed on the solder paste, and the light-emitting chip is fixed on the circuit board by soldering with the solder paste to obtain a first COB lamp plate; Bonding glue is coated around the light-emitting chip on the first COB lamp plate to obtain a second COB lamp plate; The lens is connected with the second COB lamp plate through the bonding glue, the light-emitting chip on the second COB lamp plate is located in the cavity of the lens, and a third COB lamp plate is obtained; The third COB lamp plate is placed into a back plate, and an optical film piece is combined to cover the back plate to obtain a Mini COB module.

2. The method of claim 1, wherein, The carrier plate is any one of a copper plate, an aluminum alloy plate and a steel plate.

3. The method of claim 1, wherein, In the step of providing the carrier plate, the surface of the carrier plate is processed to form convex blocks, and a mold is obtained, A numerical control machine tool is used to process the surface of the carrier plate to form convex blocks, and a mold is obtained.

4. The method of claim 1, wherein, The material of the release layer is a release agent or a release film.

5. The method of claim 1, wherein, In the step of spraying transparent glue on the release layer on the surface of the mold to obtain a transparent glue layer, The transparent glue is sprayed on the mold by using a piezoelectric valve jet dispensing machine or a screw type dispensing machine.

6. The method of claim 1, wherein, The viscosity of the transparent glue is 7000-40000 mPa.s.

7. The method of claim 1, wherein, The transparent glue has a thixotropy coefficient of 4-6 , which is equal to the thixotropy coefficient of 4-6 of the silica gel. The thixotropy coefficient of 4-6 of the silica gel means that the viscosity of the silica gel changes by 4-6 times during the change of the shear rate from 1 S to 10 S.

8. The method of claim 1, wherein, In the step of brushing solder paste on a circuit board, placing a light-emitting chip on the solder paste, and fixing the light-emitting chip on the circuit board by soldering to obtain a first COB lamp plate, The light-emitting chip is placed on the solder paste in an inverted manner.

9. The method of claim 1, wherein, In the step of coating bonding glue around the light-emitting chip on the first COB lamp plate to obtain a second COB lamp plate, Bonding glue is point-coated around the light-emitting chip on the first COB lamp plate by using a piezoelectric valve jet dispensing machine or a screw type dispensing machine.

Images