A method for preparing a secondary injection-molded LED bracket

Abstract

The present invention discloses a method for preparing a secondary injection-molded LED bracket, including the steps of substrate molding, primary injection molding, secondary injection molding, degumming, and electroplating. First, a first injection molding is performed on the LED bracket substrate to form a flat plate; after the injection molding material of the first injection molding is solidified, a second injection molding is performed on the front side of the bracket substrate to form a reflective cup. The present invention can form the insulating layer on the flat plate and the cup body of the reflective cup separately by two injection molding materials through the secondary injection molding process, so that it can meet the differentiated needs. For example, the insulating layer on the flat plate can be formed by an injection molding material with lower cost, more stability or better bonding with the substrate, and the reflective cup can be formed by a rubber material with high reflectivity, so that it can meet the lighting needs, and also solve the problem of poor bonding between the rubber material and the bracket substrate in the past.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor devices, and in particular to a method for preparing a secondary injection-molded LED bracket. Background Art

[0002] LED bracket, also known as lead frame, is a frame carrier for mass production of LEDs. Existing LED brackets generally include a metal substrate and a reflector cup. The metal substrate is etched or stamped to form a plurality of spaced welding areas. An insulating layer needs to be injected between each welding area to separate the welding areas for subsequent segmentation. The reflector cup is also formed on the surface of the metal substrate by injection molding. Generally, the reflector cup and the insulating layer are both injection molded at one time. It can be understood that the reflector cup and the insulating layer are injection molded with the same thermosetting material.

[0003] Referring to the patent document with application number 2012101197520, a pre-process of a light-emitting diode lead frame is disclosed, which sequentially includes etching or punching, sealing, debonding and electroplating. The preparation method is the same as the existing preparation method, and both form the reflector cup and the insulating layer by only one injection molding.

[0004] In the actual production process, since the thermosetting material of the insulation layer and the thermosetting material of the reflective cup are formed by one-time injection molding, in order to ensure that the reflectivity of the reflective cup meets the lighting requirements, only thermosetting materials with higher reflectivity and higher cost can be used, otherwise the lighting brightness requirements cannot be met. If a thermosetting material with a higher reflectivity is selected, due to the characteristics of this type of thermosetting material, the bonding between this thermosetting material and the metal substrate is poor, resulting in the airtightness between the thermosetting material and the metal substrate failing to meet the requirements. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing an LED bracket by secondary injection molding, wherein the LED bracket is prepared by using different injection molding materials twice, thereby solving the problem of poor bonding between the rubber material and the bracket substrate.

[0006] The present invention provides a method for preparing a secondary injection-molded LED bracket, comprising the following steps:

[0007] Step A, substrate molding, forming an LED bracket substrate on a metal substrate by etching or punching, wherein the LED bracket substrate is formed with a plurality of grooves and hollow portions that are interconnected;

[0008] Step B, one-time injection molding, injecting the LED bracket substrate prepared in step A through an injection molding device, so that the injection molding material fills the groove and the hollow part, and the injection molding material is solidified to prepare a flat plate;

[0009] Step C, secondary injection molding, injecting the flat plate in step B through an injection molding device, and forming a reflective cup on the front side of the flat plate after the injection molding material is solidified, thereby preparing an LED bracket;

[0010] Step D, debonding, debonding the surface of the LED bracket prepared in step C;

[0011] Step E, electroplating, using electroplating equipment to electroplate the LED bracket in step D to form a metal reflective layer on the surface of the LED bracket; the injection molding materials used in step B and step C are two different injection molding materials.

[0012] Preferably, the injection molding materials used in step B and step C are thermosetting materials, and the metal substrate in step A is a copper substrate or an iron substrate. Preferably, after step B, a debonding step B' is added to debond the surface of the flat plate prepared in step B.

[0013] Preferably, the step further includes performing a semi-etching roughening treatment on the LED bracket substrate, including the following steps:

[0014] Step S1, washing with pure water, washing the prepared LED bracket substrate with pure water;

[0015] Step S2, degreasing, degreasing the LED bracket substrate cleaned in step S1 with sulfuric acid having a concentration of 3 to 5%;

[0016] Step S3, super roughening, spraying the roughening liquid onto the area of ​​the LED bracket substrate to be roughened, the super roughening temperature is 24-28°C, and the Cu 2+ The concentration is 15-45 g / L, and the micro-etching amount is 0.6-1 μm;

[0017] Step S4, pickling, the pickling solution is a hydrochloric acid solution, wherein the concentration of hydrochloric acid is 3-4%, Cu 2+ Content ≤2g / L, pickling temperature 80~100℃;

[0018] Step S5, drying, drying the LED bracket substrate at a drying temperature of 80-100° C.;

[0019] Step S6, water break test, the LED bracket base after acid washing is subjected to water break test, and the water hanging time is ≥30s.

[0020] The present invention has the following beneficial effects: firstly, a first injection molding is performed on the LED bracket substrate to form a flat plate; after the injection molding material of the first injection molding is solidified and formed, a second injection molding is performed on the front side of the bracket substrate to form a reflective cup. The present invention can form the insulating layer on the flat plate and the cup body of the reflective cup separately by two injection molding materials through the secondary injection molding process, so that it can meet the differentiated needs. For example, the insulating layer on the flat plate can be formed by an injection molding material with lower cost, more stability or better bonding with the substrate, and the reflective cup can be formed by a rubber material with high reflectivity, so that it can meet the lighting needs, solving the problem of poor bonding between the rubber material and the bracket substrate in the past. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic structural diagram of a metal substrate in an embodiment;

[0022] Figure 2 Schematic diagram of the structure of the metal substrate after one-time injection molding in the embodiment;

[0023] Figure 3 Schematic diagram of the structure of the metal substrate after secondary injection molding in the embodiment;

[0024] Figure 4 is a schematic diagram of the structure of the LED bracket in the embodiment;

[0025] Figure 5 is a bottom view of the LED bracket in the embodiment;

[0026] Figure 6 yes Figure 5 Sectional view at CC;

[0027] Figure 7 yes Figure 6 Enlarged view of point A in the middle. DETAILED DESCRIPTION

[0028] For better understanding and implementation, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0029] In the description of the present invention, it should be noted that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0031] The present embodiment provides a method for preparing a secondary injection-molded LED bracket, comprising the following steps:

[0032] Step A: substrate molding: etching or punching is used to form an LED bracket substrate on a metal substrate 20, wherein the LED bracket substrate is formed with a plurality of mutually conductive grooves and hollow portions. Optionally, the metal substrate 20 may be a copper substrate or an iron substrate or other metal materials.

[0033] Step B, one-time injection molding, injecting the LED bracket substrate prepared in step A through an injection molding device so that the injection molding material fills the grooves and hollow parts, and the injection molding material is solidified to prepare a flat plate.

[0034] Step C, secondary injection molding, injection molding is performed on the flat plate in step B through an injection molding device, and after the injection molding material is solidified, a reflective cup 10 is formed on the front side of the flat plate, thereby preparing an LED bracket.

[0035] Step D, debonding, debonding the surface of the LED bracket prepared in step C.

[0036] Step E, electroplating, electroplating the LED bracket in step D using electroplating equipment to form a metal reflective layer on the surface of the LED bracket. The metal material can be gold, silver, copper, nickel, palladium, etc., and the electroplated layer can be at least one of the above metal material coatings.

[0037] Preferably, a semi-etching roughening process can be added to step A, that is, the prepared LED bracket substrate is subjected to semi-etching roughening. Roughening refers to the formation of etching marks or textures of a certain depth on the surface of the material. The etching depth and texture type can be controlled by adjusting the concentration, temperature, exposure time and properties of the etchant. By roughening the hollow and semi-etching positions, the bonding strength between the epoxy resin and the substrate can be improved, thereby improving the air tightness of the bracket. Optionally, the injection molding materials used in step B and step C are thermosetting materials such as epoxy resin or silicone.

[0038] Specifically, the half-etching roughening process may include the following steps:

[0039] Step S1, pure water cleaning, using pure water to clean the LED bracket substrate prepared in step n.

[0040] Step S2, degreasing, degreasing the LED bracket substrate cleaned in step S1 with sulfuric acid having a concentration of 3-5%.

[0041] Step S3, super roughening, spraying the roughening liquid onto the area of ​​the LED bracket substrate to be roughened, the super roughening temperature is 24-28°C, and the Cu 2+ The concentration is 15-45 g / L, and the micro-etching amount is 0.6-1 μm.

[0042] Step S4, pickling, the pickling solution is a hydrochloric acid solution, wherein the concentration of hydrochloric acid is 3-4%, Cu 2+ Content ≤2g / L, pickling temperature 80~100℃.

[0043] Step S5, drying, drying the LED bracket substrate at a drying temperature of 80-100°C.

[0044] Step S6, water break test, the LED bracket base after pickling is subjected to water break test, and the water hanging time is ≥30s. Specifically, take a piece of LED bracket substrate and put it into pure water, and then take it out vertically. If the entire LED bracket substrate is still hanging with water after 30s, it is qualified. If the water breaks in advance, it means that the board surface is not clean, or even has oil. Such workpieces will affect product quality if placed in the later process.

[0045] In step A, if Figure 1 As shown, firstly, an LED bracket substrate is formed on the metal substrate 20 by etching or punching according to the design scheme. The specific etching or punching scheme can be designed according to the requirements of the LED bracket substrate.

[0046] As an improvement, the injection molding materials used in step B and step C are two different injection molding materials. In step B, Figure 2 As shown, the first injection molding is performed on the etched or punched LED bracket substrate, combined with Figure 7 The injection molding material flows and fills all the grooves and hollow parts, so that the grooves and hollow parts of the LED bracket substrate form an insulating layer 40, and the thermoplastic material is solidified to form a flat plate. The injection molding material can be selected from low-cost black glue or a thermoplastic material that has better bonding with the bracket substrate, without considering the reflectivity requirement.

[0047] like Figure 3 and Figure 7 As shown, in step C, the flat plate prepared in step B is subjected to a second injection molding so that the front side of the flat plate forms a reflector cup 10. Since the reflector cup 10 has a high requirement for reflectivity, the thermoplastic material of the reflector cup 10 needs to be a rubber material with a high reflectivity. After the thermosetting material of the reflector cup 10 is solidified and formed, the LED bracket is prepared.

[0048] In step D and step E, the surface of the LED bracket is debonded, and then the obtained LED bracket is placed in an electroplating work station for electroplating, thereby forming a metal reflective layer on the surface of the metal substrate 20. Since the injection-molded thermosetting material is not a metal material, the metal reflective layer will not be plated on the surface of the injection-molded material.

[0049] The LED bracket prepared in this embodiment is as follows Figures 5 to 7 As shown, an insulating layer 40 is provided on the metal substrate 20, and the insulating layer 40 is arranged in the groove or / and the hollow part on the metal substrate 20, which is prepared by the one-shot injection molding process of step B and is solidified by the first injection molding material. A reflective cup 10 is provided on the front side of the metal substrate 20, and the reflective cup 10 has a cup body 30, which is prepared by the two-shot injection molding process of step C and is solidified by the second injection molding material. A metal reflective layer is provided on the bottom of the reflective cup 10 and the back surface of the metal substrate 20, and the metal reflective layer is formed by the electroplating process in step D. Lead pins and welding pads are formed on the metal substrate 20 in the reflective cup 10, and the insulating layer 40 is provided between the lead pins and the welding pads.

[0050] The preparation scheme of this embodiment is to first perform a one-time injection molding on the LED bracket substrate to form a flat plate, and after the first rubber material of the one-time injection molding is solidified, a second rubber material is used to perform a secondary injection molding on the front side of the flat plate to form a reflective cup 10. The first rubber material and the second rubber material are different injection molding materials. When preparing the flat plate (the first rubber material), a relatively low-cost black glue or a rubber material with better bonding with the metal substrate 20 can be used, and the reflective cup 10 on the front side can be made of white rubber material that can meet the high reflectivity lighting requirements, thereby achieving a differentiated effect. Different injection molding materials are used to form the insulating layer 40 and the reflective cup 10 of the flat plate respectively, so as to reduce costs, and an injection molding material with better bonding with the bracket substrate can be selected to make the flat plate, thereby improving the integrity of the flat plate and solving the problem of poor bonding between the rubber material and the bracket substrate in the past.

[0051] As a preferred solution, the LED bracket substrate in step A is prepared by etching. Specifically, in the etching step of step A, the following steps are included:

[0052] Step a, primary dust removal, first perform dust removal on the front and rear sides of the metal substrate 20, specifically by using a dust sticking machine, put the metal substrate 20 into the dust sticking machine for dust removal, the dust sticking machine drives the sticky paper to move toward the metal substrate 20 so that the dust on the metal substrate 20 adheres to the sticky paper, and optionally, the pressure of the sticky paper of the dust sticking machine is 0.2-0.4Mpa.

[0053] Step b, preheating, the dust-removed metal substrate 20 enters a preheating machine for preheating, the preheating temperature is 90-110° C., and the preheating can facilitate the subsequent bonding with the dry film.

[0054] Step c, attaching dry film, the preheated metal substrate 20 enters the laminating machine, and the laminating machine presses the dry film on the front and rear sides of the metal substrate 20. The conveying speed of the laminating machine is 2.3-3.3 m / min, the temperature of the hot laminating wheel used for laminating is 110-120°C, and the pressure of the hot laminating wheel is 0.3-0.5 MPa, and the temperature of the laminating strip used for cutting is 40-60 degrees Celsius. After the laminating machine completes the laminating of each metal substrate 20, it hot presses an indentation area on the dry film (the upper dry film and the lower dry film are pressed together, and there is no metal substrate 20 between the two), so that the indentation area is formed between two adjacent laminating stations of the dry film, and the width tolerance of the indentation area is ≤2 mm. The width of the indentation area can be measured by using a ruler to determine whether the width of the indentation area is within the tolerance range, and whether the indentation area is flat, clean, and free of bubbles can be observed, thereby determining whether the lamination of the dry film and the metal substrate 20 is uniform and whether the lamination quality meets the production standards.

[0055] Step d, exposure, after the dry film is attached to the metal substrate 20, partial areas of the dry film on the front and rear sides of the metal substrate 20 are exposed to form a pattern on the dry film. Optionally, a secondary dust removal process can be performed before exposure.

[0056] Step e: developing, removing the unexposed areas of the dry film with a developer, wherein the developer is a potassium carbonate solution, and the mass concentration of potassium carbonate is 8 to 14 g / L.

[0057] Step f: washing once, using pure water to clean the developer remaining on the surface of the dry film.

[0058] Step g, etching, using an etching solution to etch the metal substrate 20 to form the hollow portion 12 and the groove 11, the etching solution comprising the following components in mass concentration: Cu 2+ The concentration is 120-150 g / L, the hydrochloric acid concentration is 0.7-1.3 mol / L, and the rest is pure water.

[0059] Step h: secondary water washing, using pure water to clean the etching solution remaining on the metal substrate 20.

[0060] Step i: removing the dry film by using a film removal accelerator to remove the dry film on the front and back sides of the metal substrate 20.

[0061] Step j: washing three times with water, using pure water to clean the film removal accelerator remaining on the metal substrate 20.

[0062] Step k, pickling, using a pickling solution to clean the residual film removal accelerator, the pickling solution can be 3-5% sulfuric acid, 6-20g / L hydrogen peroxide and Cu 2+ One or a combination of two or more micro-etching solutions with a concentration of 5 to 45 g / L. Optionally, the pickling can be divided into two pickling steps and performed separately.

[0063] Step 1: four times of water washing, using pure water to clean the residual pickling solution on the metal substrate 20.

[0064] Step m: drying: drying the metal substrate 20 at a temperature of 80-100° C. to form an LED bracket substrate.

[0065] Although the embodiments disclosed in the present invention are as above, the above contents are only embodiments adopted for facilitating the understanding of the present invention and are not intended to limit the present invention. Any technician in the technical field to which the present invention belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A method for preparing a secondary injection-molded LED bracket, characterized in that: The following steps are involved: Step A, substrate molding, forming an LED bracket substrate on a metal substrate by etching or punching, wherein the LED bracket substrate is formed with a plurality of grooves and hollow portions that are interconnected; Step B, one-time injection molding, injection molding the LED bracket substrate prepared in step A, so that the injection molding material fills the groove and the hollow part, and the injection molding material is solidified to prepare a flat plate; Step C, secondary injection molding, performing injection molding on the flat plate in step B, and forming a reflective cup on the front side of the flat plate after the injection molding material is solidified, thereby preparing an LED bracket; Step D, debonding, debonding the surface of the LED bracket prepared in step C; Step E: electroplating: electroplating the LED bracket in step D using electroplating equipment to form a metal reflective layer on the surface of the LED bracket; Wherein, the injection molding materials used in step B and step C are both thermosetting materials, and the injection molding materials used in step B and step C are two different injection molding materials; The method further includes performing a semi-etching roughening process on the LED bracket substrate prepared in step A, including the following steps: Step S1, washing with pure water, washing the prepared LED bracket substrate with pure water; Step S2, degreasing, degreasing the LED bracket substrate cleaned in step S1 with sulfuric acid having a concentration of 3 to 5%; Step S3, super roughening, spraying the roughening liquid onto the area of ​​the LED bracket substrate to be roughened, the super roughening temperature is 24-28°C, and the Cu 2+ The concentration is 15-45 g / L, and the micro-etching amount is 0.6-1 μm; Step S4, pickling, the pickling solution is a hydrochloric acid solution, wherein the concentration of hydrochloric acid is 3-4%, Cu 2+ Content ≤2g / L, pickling temperature 80~100℃; Step S5, drying, drying the LED bracket substrate at a drying temperature of 80-100° C.; Step S6, water break test, the LED bracket base after acid washing is subjected to water break test, and the water hanging time is ≥30s.

2. The method for preparing a secondary injection-molded LED bracket according to claim 1, characterized in that: The metal substrate in step A is a copper substrate or an iron substrate.

3. The method for preparing a secondary injection-molded LED bracket according to claim 1, characterized in that: After step B, a debonding step B′ is added to debond the surface of the flat plate prepared in step B.

4. The method for preparing a secondary injection-molded LED bracket according to claim 1, 2 or 3, characterized in that: The metal reflective layer is one of gold, silver, copper, nickel and palladium.

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