COB light source and manufacturing method thereof

Abstract

The invention discloses a COB light source and a manufacturing method thereof. A BT insulating layer is laid on an aluminum substrate, and square mirror aluminum is laid in the middle area of the BT insulating layer; the copper foil layers with the same thickness as the mirror aluminum are laid on the BT insulating layer and located on the two sides of the mirror aluminum. A positive electrode pad area and a positive electrode wire area are arranged on the copper foil layer on one side, and a negative electrode pad area and a negative electrode wire area are arranged on the copper foil layer on the other side; a plurality of LED wafers are fixed on the mirror surface aluminum, and all the LED wafers are connected through bonding wires to form an LED wafer group; the negative electrode of the wafer group is connected with the negative electrode wire area through a bonding wire, and the positive electrode is connected with the positive electrode wire area through a bonding wire; all the LED wafers, the positive electrode wire area and the negative electrode wire area are surrounded in an annular box dam by the box dam glue by taking the center of the mirror surface aluminum as the circle center; and the fluorescent glue is filled in the annular box dam. The invention has the advantages of high luminous efficiency, low thermal resistance, uniform light distribution, good reliability, high cost performance and the like.

Description

Technical Field

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

[0002] With the development of LED technology, it is widely used in the lighting industry. At the same time, the market has put forward higher requirements for the brightness, reliability, and installation convenience of LEDs. In this way, the COB (Chip On Board, chip integrated into the substrate) packaging form came into being. At present, COB substrates generally use ordinary aluminum substrates and ceramic substrates: due to the low reflectivity, the luminous efficiency is usually around 85Lm / W, and the brightness of the whole lamp is low; the mirror aluminum substrate has a reflectivity of 98%, which can provide higher luminous efficiency and meet the needs of different fields. At present, COB mirror aluminum substrates generally adopt the design of the entire functional area (light-emitting area) mirror, and the mirror reflectivity is as high as 98%, which can provide higher luminous efficiency, but the mirror production cost is relatively high, and the COB light source produced by this solution is not cost-effective. Summary of the invention

[0003] In view of the above problems, the present invention discloses a COB light source and a manufacturing method thereof, which solves the problems of low reflectivity and high price of the COB substrate in the prior art.

[0004] The specific technical solutions are as follows:

[0005] A COB light source comprises a mirror aluminum substrate, an LED chip, a dam, a fluorescent glue, and a bonding wire. The mirror aluminum substrate comprises a substrate body, a BT insulating layer, a copper foil layer, and mirror aluminum. A BT insulating layer is applied on the surface of the substrate body, the mirror aluminum is applied in the middle of the BT insulating layer, the copper foil layers are applied on both sides of the mirror aluminum on the surface of the BT insulating layer, the copper foil layer has the same thickness as the mirror aluminum, a positive electrode pad region and a positive electrode line region are provided on the copper foil layer on one side of the mirror aluminum, and a negative electrode pad region and a negative electrode line region are provided on the copper foil layer on the other side, and white oil layers are applied on the surfaces of the two copper foil layers except for the positive and negative electrode pads and the positive and negative electrode line regions;

[0006] There are several LED chips, which are arranged on the mirror aluminum. Several chips are connected by bonding wires to form an LED chip group. The positive and negative electrodes at both ends of the LED chip group are respectively connected to the positive electrode line area and the negative electrode line area by bonding wires, so that the positive and negative electrodes of the LED chip group are respectively connected to the positive pad area and the negative pad area; the dam is annular and is arranged on the mirror aluminum and two copper foil layers with the center of the mirror aluminum as the center of the circle. The LED chip group, the positive electrode line area and the negative electrode line area are all located in the dam, and the inner side of the dam is filled with fluorescent glue.

[0007] Furthermore, the mirror aluminum and the aluminum foil layer are both rectangular, and the lengths of the mirror aluminum and the copper foil layer are consistent with the length of the BT insulating layer, and the mirror aluminum and the copper foil layer completely cover the BT insulating layer.

[0008] Furthermore, the distances between the positive electrode line region and the negative electrode line region and the mirror aluminum are equal, and the horizontal axes of the positive and negative electrode line regions are perpendicular to the left and right sides of the mirror aluminum.

[0009] Furthermore, a plurality of the LED chips are arranged at equal intervals in a plurality of rows / columns and fixed on the mirror aluminum, and the intervals between adjacent LED chips in each row / column are equal.

[0010] Furthermore, several of the LED chips are connected in series in sequence via bonding wires; or several LED chips are divided into several groups, and the LED chips in each group are connected in series in sequence via bonding wires, and each group is connected in series in sequence via bonding wires.

[0011] Based on the above content, the present invention also provides a method for manufacturing a COB light source, which specifically includes the following steps:

[0012] Step 1: Lay a BT insulation layer on the surface of the square substrate body;

[0013] Step 2: Lay the square mirror aluminum on the middle area of ​​the surface of the BT insulation layer, with the two ends of the mirror aluminum flush with the two ends of the BT insulation layer, and make the center of the mirror aluminum correspond to the center of the BT insulation layer;

[0014] Step 3: Lay two copper foil layers with the same thickness as the mirror aluminum on the BT insulation layer, and the two copper foil layers are respectively located on both sides of the mirror aluminum, and the mirror aluminum and the two copper foil layers completely cover the BT insulation layer;

[0015] Step 4: Set a positive pad area and a positive electrode line area on the copper foil layer on one side of the mirror aluminum, and set a negative pad area and a negative electrode line area on the copper foil layer on the other side. The positive and negative electrode line areas are respectively located on both sides of the mirror aluminum, and the distances from the mirror aluminum are consistent; except for the positive and negative electrode line areas and the positive and negative pad areas, cover the other areas of the copper foil layer with highly reflective white oil to form a white oil layer, and the mirror aluminum substrate is completed;

[0016] Step 5: Fix several LED chips on the mirror aluminum with a solid crystal adhesive, and put the mirror aluminum substrate with LED chips into a constant temperature box to cure the solid crystal adhesive;

[0017] Step 6: Use bonding wires to connect all LED chips to form an LED chip group, connect the negative electrode of the LED chip group to the negative electrode line area, and connect the positive electrode of the LED chip group to the positive electrode line area;

[0018] Step 7: With the center of the mirror aluminum as the center of the circle, use dam glue to enclose all LED chips and the positive and negative electrode line areas in a ring-shaped dam; put the mirror aluminum substrate with the dam into a constant temperature box to cure the dam;

[0019] Step 8: Fill the dam with fluorescent glue and test it. After passing the test, put it into a constant temperature box to cure the fluorescent glue. After curing, the finished COB light source is obtained.

[0020] Furthermore, in the step 1, the thickness of the substrate body is 0.6 mm-0.8 mm, and the thickness of the BT insulation layer is 0.22 mm-0.26 mm.

[0021] Furthermore, when the die-bonding adhesive is cured in step five, the curing temperature is 150° C. and the curing time is 120 minutes.

[0022] Furthermore, when the dam glue is cured in step seven, the curing temperature is 130° C. and the curing time is 30 minutes.

[0023] Furthermore, in step eight, the fluorescent glue is cured by staged curing, the first stage curing temperature is 100°C, and the curing time is 30 minutes; the second stage curing temperature is 130°C, and the curing time is 60 minutes; the third stage curing temperature is 150°C, and the curing time is 180 minutes.

[0024] Furthermore, in step eight, the finished COB light sources are tested again, and the finished COB light sources that pass the test are retained.

[0025] The beneficial effects of the present invention are embodied in:

[0026] (1) The present invention eliminates the conventional patch and reflow soldering process, reduces equipment investment in production, and improves production efficiency. The COB light source has the advantages of high luminous efficiency, low thermal resistance, uniform light distribution, and good reliability.

[0027] (2) The present invention divides the functional area into two parts, selectively plates mirror aluminum in the chip area, and covers other areas with highly reflective white oil. While ensuring the lighting effect, it saves production costs and has a higher cost-effectiveness than conventional mirror aluminum COB light sources. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a side view of the present invention;

[0029] Figure 2 It is the front view of the present invention;

[0030] Explanation of the accompanying drawings: 1. Substrate body, 2. BT insulation layer, 3. Copper foil layer, 4. Mirror aluminum, 5. Mirror aluminum substrate, 6. Cathode pad area, 7. LED chip, 8. Bonding wire, 9. Dam glue, 10. Fluorescent glue, 11. Positive pad area, 12. Cathode electrode line area, 13. Positive electrode line area. DETAILED DESCRIPTION

[0031] In order to make the technical solution of the present invention clearer, the present invention is further described below in conjunction with the accompanying drawings. Any equivalent replacement of the technical features of the technical solution of the present invention and any solution derived from conventional reasoning shall fall within the protection scope of the present invention. The fixed connection and fixed setting mentioned in the present invention are all common connection methods in the mechanical field, including welding, bolt and nut connection, and screw connection.

[0032] In the description of the present invention, it should be understood 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, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0033] Please see attached Figure 1-2 The present embodiment provides a COB light source, including a mirror aluminum substrate 5, an LED chip 7, and a dam 9. The mirror aluminum substrate 5 includes a substrate body 1 with a thickness of 0.6mm-0.8mm, a BT insulation layer 2 with a thickness of 0.22mm-0.26mm, a copper foil layer 3, and a mirror aluminum 4. The substrate body 1 is a square aluminum substrate, and a BT insulation layer 2 is applied on the surface of the substrate body 1. Mirror aluminum is laid in the middle of the BT insulating layer 2, and the center of the mirror aluminum corresponds to the center of the BT insulating layer 2, and the length of the mirror aluminum 4 is equal to the side length of the BT insulating layer 2; copper foil layers 3 are laid on both sides of the mirror aluminum on the surface of the BT insulating layer 2, and the thickness of the copper foil layer 3 is consistent with that of the mirror aluminum, so that its surface is flush, and the copper foil layer 3 on one side of the mirror aluminum is provided with a positive pad area 11 and a positive electrode line area 13, and the copper foil layer 3 on the other side of the mirror aluminum is provided with a negative pad area 6 and a negative electrode line area 12. The surfaces of the two copper foil layers 3 are coated with a layer of white oil except for the positive and negative pads and the positive and negative electrode line areas. The white oil layer used in this embodiment is PCB circuit board ink, specifically the photosensitive solder mask super white oil model LB-1900W-16H-1 produced by Dongguan Lanbang Electronic Hardware Materials Co., Ltd., which has high reflectivity.

[0034] Furthermore, since the copper foil layers 3 are arranged on the left and right sides of the mirror aluminum, and there is no copper foil layer 3 on the top and bottom of the mirror aluminum, the heat dissipation performance of the COB light source of this embodiment is better.

[0035] There are several LED chips 7 which are arranged on the mirror aluminum 4. The several chips are connected by bonding wires 8 to form an LED chip group. The dam 9 is ring-shaped and is arranged on the mirror aluminum and two copper foil layers 3 with the center of the mirror aluminum as the center. The LED chip group, the positive electrode line area 13 and the negative electrode line area 12 are all located in the dam 9, and the inside of the dam is filled with fluorescent glue 10, which covers the LED chip group, the positive electrode line area 13 and the negative electrode line area 12.

[0036] In this embodiment, a number of LED chips are arranged in a number of rows / columns at equal intervals and fixed on the mirror aluminum 4, and the intervals between adjacent LED chips in each row / column are equal. The LED chips in each row / column can be connected in series, in parallel, in part in series or in part in parallel through bonding wires; each row / column can also be connected in series, in parallel, in part in series or in part in parallel through bonding wires. The use of bonding wires makes it possible to have no circuit distribution on the mirror aluminum, reduce mutual interference between circuits, and make the structure simpler.

[0037] Since there is a dam, and the positive and negative electrode pad areas are not within the dam, if the positive and negative electrodes of the chip group are directly connected to the positive and negative electrode pad areas using bonding wires 8, the service life of the COB light source will be affected and it is easily affected by external interference. Therefore, in this embodiment, a rectangular positive electrode line area 13 is provided on the copper foil layer 3 provided with the positive electrode pad area 11, and a rectangular negative electrode line area is provided on the copper foil layer 3 provided with the negative electrode pad area 6, and the positive and negative electrode line areas are both within the dam, and the negative electrode of the LED chip group is connected to the negative electrode line area 12 through a bonding wire, thereby connecting to the negative electrode pad area 6; the positive electrode is connected to the positive electrode line area 13 through a bonding wire, thereby connecting to the positive electrode pad area 11. The service life of the COB light source is extended, external interference is reduced, and the structure is simplified.

[0038] In this embodiment, the mirror aluminum 4 and the aluminum foil layer are both rectangular, and the lengths of the mirror aluminum and the copper foil layer 3 are consistent with the length of the BT insulating layer 2, and the sum of the areas of the mirror aluminum 4 and the copper foil layer 3 is equal to the area of ​​the BT insulating layer 2, thereby completely covering the BT insulating layer 2 and the substrate body 1.

[0039] In this embodiment, the positive electrode line area and the negative electrode line area are both long strips, and the distance between the positive electrode line area and the negative electrode line area and the mirror aluminum is equal. The positive and negative electrode line areas in this embodiment are distributed on the left and right sides of the mirror aluminum, and the horizontal axes of the positive and negative electrode line areas are perpendicular to the left and right sides of the mirror aluminum 4. If the copper foil layer 3 is laid on the upper and lower sides of the mirror aluminum, the horizontal axes of the positive and negative electrode line areas are parallel to the mirror aluminum.

[0040] like Figure 1 In the embodiment shown, the first to nth LED chips 7 are divided into x rows of chips, and the number of chips in each row of chips is equal. The number of chips in each row of chips may also be unequal. The distance between two adjacent LED chips in each row of chips is L, and the distance between adjacent chip rows is equal. This arrangement enables the COB light source to dissipate heat and emit light evenly. The chips in each row of chips are connected in series in sequence using bonding wires, and each row of chips is connected in series in sequence using bonding wires to form a chip group. The end of the first LED chip that is not connected to the second LED chip is set as the negative electrode of the chip group, and the end of the nth LED chip that is not connected to the n-1th LED chip is set as the negative electrode of the chip group.

[0041] This embodiment also provides a method for manufacturing a COB light source, which specifically includes the following steps:

[0042] Step 1: Laying a BT insulation layer 2 on the surface of a substrate body 1 with a side length a, wherein the side length of the BT insulation layer 2 is a.

[0043] Step 2: Apply square mirror aluminum to the middle area of ​​the surface of the BT insulation layer 2, with both ends of the mirror aluminum flush with both ends of the BT insulation layer 2, the width of the BT insulation layer 2 is b, and the center of the mirror aluminum corresponds to the center of the BT insulation layer 2.

[0044] Step three: lay two copper foil layers 3 with the same thickness as the mirror aluminum on the BT insulating layer 2, and the two copper foil layers 3 are respectively located on both sides of the mirror aluminum. The two copper foil layers 3 are respectively located on both sides of the mirror aluminum, and the length of the two copper foil layers 3 is a, and the width is ab / 2, respectively, and the mirror aluminum and the two copper foil layers 3 are completely covered on the BT insulating layer 2.

[0045] Step 4: Set a positive pad area 11 and a positive electrode line area on the copper foil layer 3 on one side of the mirror aluminum, and set a negative pad area 6 and a negative electrode line area on the copper foil layer 3 on the other side. The positive and negative electrode line areas are respectively located on both sides of the mirror aluminum, and the distances from the mirror aluminum are consistent; except for the positive and negative electrode line areas and the positive and negative pad areas, a white oil layer is covered on other areas of the copper foil layer 3 to form a white oil layer, and the mirror aluminum substrate 5 is completed.

[0046] Step 5: Fix several LED chips 7 on the mirror aluminum by using a bonding adhesive, and put the mirror aluminum substrate 5 with LED chips into a constant temperature box to cure the bonding adhesive at a curing temperature of 150° C. and a curing time of 120 minutes.

[0047] Step 6: Use bonding wires to connect all LED chips to form an LED chip group, connect the negative electrode of the LED chip group to the negative electrode line area, and connect the positive electrode of the LED chip group to the positive electrode line area.

[0048] Step 7: With the center of the mirror aluminum as the center of the circle, use dam glue to enclose all LED chips and the positive and negative electrode line areas in a circular dam; put the mirror aluminum substrate 5 with the dam into a constant temperature box to cure the dam at a curing temperature of 130°C and a curing time of 30 minutes.

[0049] Step 8: Fill the dam with fluorescent glue and test it. After passing the test, put it into a constant temperature box and cure the fluorescent glue in sections. After curing, the finished COB light source is obtained. When the fluorescent glue is cured in sections, the first section curing temperature is 100°C and the curing time is 30 minutes; the second section curing temperature is 130°C and the curing time is 60 minutes; the third section curing temperature is 150°C and the curing time is 180 minutes. Through the section curing, the fluorescent glue and the mirror aluminum substrate 5 have better bonding and better performance.

[0050] Step 9: Use the photoelectric parameter tester to test the finished COB light source again, and keep the finished COB light source that passes the test.

[0051] By selectively plating mirror aluminum in the chip area and covering other areas with highly reflective white oil, the production cost is saved while ensuring the lighting effect, and it has a higher cost-effectiveness than conventional mirror aluminum COB light sources.

[0052] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A COB light source, comprising a mirror aluminum substrate (5), an LED chip (7), a dam (9), a fluorescent glue (10), and a bonding wire (8), characterized in that: The mirror aluminum substrate (5) comprises a substrate body (1), a BT insulation layer (2), a copper foil layer (3), and mirror aluminum (4); a BT insulation layer (2) is applied on the surface of the substrate body (1); the mirror aluminum (4) is applied in the middle of the BT insulation layer (2); the copper foil layer (3) is applied on the surface of the BT insulation layer (2) on both sides of the mirror aluminum (4); the thickness of the copper foil layer (3) is consistent with that of the mirror aluminum (4); a positive electrode pad region (11) and a positive electrode line region (13) are provided on the copper foil layer (3) on one side of the mirror aluminum; a negative electrode pad region (6) and a negative electrode line region (12) are provided on the copper foil layer (3) on the other side; and white oil layers are coated on the surfaces of the two copper foil layers (3) except for the positive and negative electrode pads and the positive and negative electrode line regions; The LED chips (7) are arranged in a plurality and arranged on the mirror aluminum (4). The plurality of chips are connected in series in sequence through bonding wires (8) to form an LED chip group. The positive electrode and the negative electrode at both ends of the LED chip group are respectively connected to the positive electrode line area (13) and the negative electrode line area (12) through bonding wires, so that the positive electrode and the negative electrode of the LED chip group are respectively connected to the positive electrode pad area (11) and the negative electrode pad area (6). The dam (9) is annular and is arranged on the mirror aluminum and the two copper foil layers (3) with the center of the mirror aluminum (4) as the center of the circle. The LED chip group, the positive electrode line area and the negative electrode line area are all located in the dam (9), and the inner side of the dam is filled with fluorescent glue (10).

2. A COB light source as claimed in claim 1, characterized in that: The mirror aluminum (4) and the aluminum foil layer are both rectangular, and the lengths of the mirror aluminum and the copper foil layer (3) are consistent with the lengths of the BT insulation layer (2). The mirror aluminum (4) and the copper foil layer (3) completely cover the BT insulation layer (2).

3. A COB light source as claimed in claim 1, characterized in that: The distances between the positive electrode line region (13) and the negative electrode line region (12) and the mirror aluminum (4) are equal, and the horizontal axes of the positive and negative electrode line regions are perpendicular to the left and right sides of the mirror aluminum.

4. A COB light source as claimed in claim 1, characterized in that: A plurality of LED chips (7) are arranged at equal intervals and divided into a plurality of rows / columns and fixed on the mirror aluminum (4), and the intervals between adjacent LED chips in each row / column are equal.

5. A COB light source as claimed in claim 1, characterized in that: A plurality of the LED chips are connected in series in sequence via bonding wires (8); or a plurality of LED chips are divided into a plurality of groups, the LED chips in each group are connected in series in sequence via bonding wires, and each group is connected in series in sequence via bonding wires.

6. A method for manufacturing a COB light source according to any one of claims 1 to 5, characterized in that: The specific steps include: Step 1: Laying a BT insulation layer (2) on the surface of the square substrate body (1); Step 2: laying a square mirror aluminum (4) on the middle area of ​​the surface of the BT insulation layer (2), with the two ends of the mirror aluminum (4) flush with the two ends of the BT insulation layer (2), and making the center of the mirror aluminum correspond to the center of the BT insulation layer (2); Step 3: Laying two copper foil layers (3) having the same thickness as the mirror aluminum on the BT insulation layer (2), the two copper foil layers (3) being located on both sides of the mirror aluminum (4) respectively, and making the mirror aluminum (4) and the two copper foil layers (3) completely cover the BT insulation layer (2); Step 4: a positive electrode pad region (11) and a positive electrode line region (13) are arranged on the copper foil layer (3) on one side of the mirror aluminum, and a negative electrode pad region (6) and a negative electrode line region (12) are arranged on the copper foil layer (3) on the other side, wherein the positive and negative electrode line regions are respectively located on both sides of the mirror aluminum and are at the same distance from the mirror aluminum; except for the positive and negative electrode line regions and the positive and negative electrode pad regions, other regions of the copper foil layer (3) are covered with highly reflective white oil to form a white oil layer, and the mirror aluminum substrate (5) is manufactured; Step 5: Fix a plurality of LED chips (7) on the mirror aluminum (4) by using a solid crystal adhesive, and place the mirror aluminum substrate (5) with the LED chips into a constant temperature box to cure the solid crystal adhesive; Step 6: Use bonding wires (8) to connect all LED chips (7) to form an LED chip group, connect the cathode of the LED chip group to the cathode electrode line region (12), and connect the anode of the LED chip group to the anode electrode line region; Step 7: With the center of the mirror aluminum as the center of the circle, all LED chips and the positive and negative electrode line areas are enclosed in a ring-shaped dam (9) using dam glue; the mirror aluminum substrate (5) with the dam (9) is placed in a constant temperature box to cure the dam; Step 8: Fill the dam with fluorescent glue and test it. After passing the test, put it into a constant temperature box to cure the fluorescent glue. After curing, the finished COB light source is obtained.

7. A method for manufacturing a COB light source as claimed in claim 6, characterized in that: In the step 1, the thickness of the substrate body (1) is 0.6 mm-0.8 mm, and the thickness of the BT insulation layer (2) is 0.22 mm-0.26 mm.

8. A method for manufacturing a COB light source as claimed in claim 6, characterized in that: When the die-bonding adhesive is cured in step 5, the curing temperature is 150° C. and the curing time is 120 minutes.

9. A method for manufacturing a COB light source as claimed in claim 6, characterized in that: When the dam glue is cured in step seven, the curing temperature is 130° C. and the curing time is 30 minutes.

10. A method for manufacturing a COB light source according to claim 6, characterized in that: In step eight, the fluorescent glue is cured by segmented curing. The first segment curing temperature is 100°C and the curing time is 30 minutes; the second segment curing temperature is 130°C and the curing time is 60 minutes; the third segment curing temperature is 150°C and the curing time is 180 minutes.

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