A high-light-efficiency flip-chip COB light source and its packaging method

Abstract

The present application relates to a high-light-efficiency flip-chip COB light source and a packaging method thereof, comprising: a substrate assembly, a light source area being provided on the substrate assembly, a reflective white glue layer being laid inside the light source area, a plurality of groups of electrode pads being provided on the substrate assembly, each of the plurality of groups of electrode pads being provided with a welding layer, a plurality of chips, each chip being provided one-to-one on each group of electrode pads and welded to the electrode pads via the welding layer, the reflective white glue layer being located at the height of the lower surface of the chip, and a plurality of protrusions being provided on the reflective white glue layer for enclosing the connection between the electrode pads and the chip. The reflective white glue layer can evenly cover each electrode pad and the welding layer provided on the electrode pads, thereby reducing the effect of the electrode pads and the welding layer on the reflectivity of the substrate, and covering impurities volatilized during the welding process of the welding layer and remaining on the surface of the chip gaps, thereby improving the overall reflectivity of the device and optimizing the luminous effect.

Description

Technical Field

[0001] The present application relates to the technical field of COB light sources, and in particular to a high-light-efficiency flip-chip COB light source and a packaging method thereof. Background Art

[0002] At present, with the continuous advancement of LED technology, people's performance requirements for LED light sources are constantly increasing, especially COB light sources with high light efficiency advantages. People have higher and higher requirements for light efficiency and require costs to be continuously reduced, which makes the cost per lumen of light sources continue to decline.

[0003] Flip-chip COB eliminates the high-cost gold wire, and the reliability of flip-chip soldering is also better than that of regular installation. Therefore, improving the performance of flip-chip COB light sources is an important direction for the development of COB light source packaging technology.

[0004] However, the current reflectivity of the flip-chip substrate is difficult to achieve the reflectivity of more than 98% of the face-mounted mirror aluminum substrate, and the flip-chip die bonding also has problems such as flux volatilization affecting the reflectivity of the substrate, which greatly reduces the luminous effect of the flip-chip COB light source. Summary of the Invention

[0005] The present application provides a high-light-efficiency flip-chip COB light source and a packaging method thereof, which can solve the problems of low reflectivity of the flip-chip substrate and the influence of flux on substrate reflection during flip-chip die bonding.

[0006] The technical solution of this application is as follows: A high-efficiency flip-chip COB light source, comprising:

[0007] A substrate assembly, wherein the substrate assembly is provided with a light source area, a reflective white glue layer is laid inside the light source area, and multiple groups of electrode pads are provided on the substrate assembly, and each of the multiple groups of electrode pads is provided with a welding layer; and

[0008] Multiple chips, each chip is arranged one by one on each group of electrode pads, and is welded to the electrode pads through a welding layer. The height of the reflective white glue layer is located at the lower surface of the chip, and is used to fill the gaps between the multiple electrode pads and the side walls of the welding layer. The reflective white glue layer is provided with multiple protrusions for enclosing the connection between the electrode pads and the chip.

[0009] By adopting the above solution, the reflective white glue layer can evenly cover each electrode pad and the welding layer arranged on the electrode pad, thereby reducing the influence of the electrode pad and the welding layer on the reflectivity of the substrate, and covering the impurities volatilized during the welding process of the welding layer and remaining on the surface of the chip gap, so as to improve the overall reflectivity of the device and optimize the luminous effect.

[0010] In one embodiment of the present application, each group of electrode pads includes two copper electrode pads spaced apart from each other, the reflective white glue layer is also filled between the two copper electrode pads, and the thickness d of the reflective white glue layer satisfies: 80um≤d≤300um.

[0011] In one embodiment of the present application, the light source area is a sink groove opened on the substrate assembly; or

[0012] It also includes a dam glue, which is connected end to end to enclose the light source area.

[0013] By adopting the above-mentioned scheme, a dam glue is used to enclose or a groove is directly opened on the substrate assembly to form a light source area, and a flat reflective white glue layer is coated in the light source area. The light source area can effectively prevent the internal reflective white glue layer from overflowing, and a chip is arranged inside the light source area so that the reflective white glue layer can increase the reflectivity of the substrate in the light source area to enhance the luminous effect.

[0014] In one embodiment of the present application, a projection of an end of each group of electrode pads away from the substrate assembly on the substrate assembly is located within a projection area of ​​the corresponding chip on the substrate assembly.

[0015] By adopting the above solution, when the electrode pad is welded, the melted solder layer on it will not protrude from the edge of the chip when it overflows, but will flow along the surface of the electrode pad, thereby avoiding the situation where the surface solder layer protrudes from the edge of the chip and the reflective white glue layer fails to cover the protruding solder layer, thereby affecting the luminous efficiency.

[0016] In one embodiment of the present application, the substrate assembly includes a metal heat sink, an insulating layer and a copper circuit layer, the insulating layer is arranged on the upper surface of the metal heat sink, and the copper circuit layer is arranged on the upper surface of the insulating layer; or

[0017] The substrate assembly includes an insulating substrate and a copper circuit layer, and the copper circuit layer is arranged on the upper surface of the insulating substrate.

[0018] By adopting the above solution, by setting a metal heat sink coated with an insulating layer as a substrate, or using a conventional ceramic insulating substrate, the entire substrate assembly can ensure its good electrical insulation while improving its thermal conductivity, avoiding severe thermal resistance due to heat generation, which affects the luminous effect of the device.

[0019] In one embodiment of the present application, multiple groups of electrode pads are arranged at intervals along the copper circuit layer, and the copper circuit layer also includes multiple connection areas. The lower end of the copper circuit layer is assembled on the connection area and is electrically connected to the copper circuit layer. The upper end thereof passes through the reflective white glue layer and is electrically connected to the chip. The width of the connection area is not less than the width of the electrode pad, and the length of the connection area is not less than half the length of the chip.

[0020] By adopting the above scheme, the reflective white glue layer is used to fill the gap between the bottom of the electrode pad and the lower surface of the chip, so that the reflective white glue layer can ensure its own thickness and flatness, while completely covering the welding layer, copper circuit layer and electrode pad after chip welding, so as to improve the reflectivity of the entire substrate and enhance the luminous effect of the device. At the same time, the length and width of the connection area connected to the chip are limited, and the connection area provided on the copper circuit layer is used to assist in heat dissipation of the entire circuit loop, thereby improving the heat dissipation capacity of the device.

[0021] In one embodiment of the present application, the height of the electrode pad is not less than 80um, the thickness of the electrode pad is greater than the thickness of the copper circuit layer, and the difference between the thickness of the electrode pad and the thickness of the copper circuit layer is not less than 30um.

[0022] By adopting the above solution and determining the thickness of the electrode pad and the copper circuit layer, the thickness requirement of the subsequent reflective white glue layer can be met when filling. While reducing costs and improving heat dissipation capacity, the reflectivity of the entire substrate can be improved and its luminous effect can be enhanced.

[0023] In one embodiment of the present application, a phosphor glue layer is further included. The phosphor glue layer is laid in the light source area and covers the plurality of chips.

[0024] By adopting the above solution and providing a phosphor glue layer, the luminous efficiency, light color quality and light spot uniformity of the device are further improved by utilizing its high light transmittance, high refractive index, good thermal stability and low stress characteristics.

[0025] In one embodiment of the present application, two light source pads are further included. The two light source pads are assembled on the substrate assembly and are located outside the light source area. Both of the light source pads are electrically connected to the copper circuit layer.

[0026] A second object of the present invention is to provide a packaging method for a flip-chip COB light source with high light efficiency.

[0027] In order to achieve the above objectives, the technical solutions of this application are as follows:

[0028] A packaging method for a high-light-efficiency flip-chip COB light source comprises the following steps:

[0029] Step 1: setting a light source area on the substrate, setting a copper circuit layer inside the light source area, and setting a plurality of electrode pads along the copper circuit layer;

[0030] Step 2: Setting a soldering layer on each electrode pad and fixing the chip on the soldering layer;

[0031] Step 3: Laying a reflective white glue layer in the gaps between the multiple electrode pads in the light source area, so that it covers each electrode pad and the welding layer provided on the electrode pad;

[0032] Step 4: Lay the phosphor glue layer on the high-reflective white glue layer and encapsulate it.

[0033] By adopting the above scheme and the process of first bonding the crystal and then dispensing the glue, the entire light source area except the chip is covered with the reflective white glue layer, wherein the covered positions include but are not limited to: impurities volatilized and covered on the surface of the bracket during bonding the crystal, the welding layer and the electrode pad. At the same time, by controlling the thickness of the reflective white glue layer during dispensing the glue, it will not bulge between adjacent chips after dispensing, thereby avoiding blocking the light output from the side of the chip.

[0034] In summary, this application includes at least one of the following beneficial technical effects:

[0035] 1. A light source area is set on the substrate. In the light source area, the chips are fixed first and then glued, so that the gaps between the chips are evenly coated with a reflective white glue layer. The reflective white glue layer is used to cover and shield the low-reflective white oil of the traditional package, impurities generated during welding, electrode pads and exposed welding layers. At the same time, it is ensured that the reflective white glue layer does not affect the side light output of the chip, thereby avoiding the influence of the electrode pads and welding layer on the reflectivity of the device substrate, so as to improve the overall luminous effect of the device.

[0036] 2. By setting up a metal heat sink or ceramic substrate, when the chip is assembled on the substrate, by coating an insulating layer on the metal heat sink, it can ensure its own electrical insulation while improving its thermal conductivity, just like the ceramic substrate.

[0037] 3. By limiting the length and width of the copper circuit layer between two adjacent chips, the copper circuit layer is used for auxiliary heat dissipation while ensuring that the actual working conditions are met, thereby improving the heat dissipation capacity of the entire circuit loop.

[0038] 4. By providing a phosphor layer, the excellent light transmittance of the phosphor layer is utilized to further enhance the luminous effect of the device. At the same time, controlling the shape of the phosphor layer itself can improve the color uniformity and light efficiency of the chip.

[0039] 5. By limiting the area of ​​the electrode pad, the soldering layer will not protrude from the outer edge of the chip during soldering, thereby avoiding the adverse effect of the protruding solder layer on the reflectivity of the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 1 is a cross-sectional schematic diagram of a high-light-efficiency flip-chip COB light source provided in the first embodiment of the present application;

[0041] Figure 2 1 is a schematic plan view of a high-light-efficiency flip-chip COB light source provided in an embodiment of the present application;

[0042] Figure 3 This is a cross-sectional schematic diagram of a high-light-efficiency flip-chip COB light source provided in the second embodiment of the present application.

[0043] Explanation of the accompanying symbols: 1. Electrode pad; 2. Substrate assembly; 21. Insulation layer; 22. Metal heat sink; 23. Insulation substrate; 3. Phosphor glue layer; 4. Welding layer; 5. Copper circuit layer; 6. Reflective white glue layer; 7. Chip; 8. Dam glue; 9. Light source pad. DETAILED DESCRIPTION

[0044] The following is combined with Figure 1-3 The present application provides a high-light-efficiency flip-chip COB light source and a packaging method thereof for further detailed description.

[0045] See also Figure 1-3 A high-efficiency flip-chip COB light source, comprising: a substrate assembly 2 and a plurality of chips 7

[0046] A substrate assembly 2, wherein the substrate assembly 2 is provided with a light source area, a reflective white glue layer 6 is laid inside the light source area, and multiple groups of electrode pads 1 are provided on the substrate assembly 2, and each of the multiple groups of electrode pads 1 is provided with a welding layer 4; and

[0047] A plurality of chips 7, each of the chips 7 is arranged on each group of the electrode pads 1 in a one-to-one correspondence, and is welded to the electrode pads 1 through the welding layer 4, the height of the reflective white glue layer 6 is located at the position of the lower surface of the chip 7, and is used to fill the gaps between the plurality of the electrode pads 1 and the side walls of the welding layer 4, and the reflective white glue layer 6 is provided with a plurality of protrusions for enclosing the connection between the electrode pad 1 and the chip 7, wherein the height of the electrode pad 1 is not less than 80um, wherein the reflective white glue layer 6 is coated to ensure that its thickness can contact the lower surface of the chip 7, and at the same time, due to the influence of the surface tension of the reflective white glue layer 6, the reflective white glue layer 6 after coating can form as shown in the appendix of the specification Figure 1Or the shape shown in 3, so that it can cover the electrode pad 1 and the welding layer 4, as well as the lower surface of the chip 7. Since the organic silicone rubber used for phosphor powder mixing has a certain ability to permeate water vapor and sulfur and chlorine atoms, it is encapsulated using a reflective white glue layer with good waterproof and sulfur and chlorine properties, which effectively avoids the diffusion of external water vapor or sulfur and chlorine impurities into the chip electrodes during the flip-chip soldering process, greatly improving the reliability of the packaged light source, and also avoiding the problems of high cost and poor chip heat dissipation due to excessive thickness, ensuring that the reflective white glue layer 6 can remain flat;

[0048] In this embodiment, the reflective white glue layer 6 is a silicone rubber layer. The reflective white glue layer 6 uses a silicone rubber layer with high reflectivity and a reflectivity greater than 98% to coat the inner surface of the light source area. The reflective white glue layer 6 can improve the overall reflectivity of the device. At the same time, since the reflective white glue layer 6 covers the electrode pad 1 and the welding layer 4 after the electrode pad and the chip 7 are connected through the welding layer 4, the two are prevented from affecting the overall reflectivity of the device.

[0049] Each group of electrode pads 1 includes two copper electrode pads arranged at intervals, and the reflective white glue layer 6 is also filled between the two copper electrode pads, and the thickness d of the reflective white glue layer 6 satisfies: 80 um≤d≤300 um. By setting two copper electrode pads and setting a welding layer 4 on the copper electrode pads, the chip 7 is reflow-soldered on the two copper electrode pads, and the two copper electrode pads are electrically connected to the chip 7.

[0050] In this embodiment, the reflective white glue layer 6 covers the electrode pad 1 and the welding layer 4 on the lower surface of the chip 7, avoiding the influence of the electrode pad 1 and the welding layer 4 on the reflectivity of the substrate, which can effectively improve the reflectivity of the device, while helping to stabilize the chip 7 and having good thermal conductivity and electrical insulation properties.

[0051] The light source area is a sink groove opened on the substrate assembly 2, and the dispensing and coating process of the reflective white glue layer 6 is carried out inside the sink groove. Compared with the technical solution of using the dam glue 8 to enclose the light source area, it can also prevent the reflective white glue layer 6 from overflowing; or

[0052] It also includes a dam glue 8, which is connected end to end to enclose the light source area. The dam glue 8 performs a dam operation on the light source area, and the circled area is the light source area. The cured dam glue 8 blocks the overflow of the internal reflective white glue layer 6. At the same time, its own optical properties can optimize the light-emitting angle and light effect of the light source, making the light source more uniform.

[0053] In this embodiment, the dam glue 8 can be made of white wall glue with high reflectivity.

[0054] The projection of the end of each group of electrode pads 1 away from the substrate assembly 2 on the substrate assembly 2 is located within the projection area of ​​the corresponding chip 7 on the substrate assembly 2. Since the welding layer 4 will overflow glue to all sides during crystal bonding, it is necessary to set the upper surface area of ​​the electrode pad 1 to be smaller than the lower surface area of ​​the chip 7. At this time, even if glue overflows, the welding layer 4 will not protrude from the edge of the chip 7, thereby ensuring that the reflective white glue layer 6 can completely cover the electrode pad 1 and the welding layer 4 to ensure its light extraction efficiency.

[0055] In this embodiment, the distance between each edge of the electrode pad 1 and each edge of the corresponding chip is 50-150um, so that the surface area of ​​the upper end face of the electrode pad 1 is smaller than the chip area. During the reflow soldering of the welding layer, the welding layer will not protrude from the side of the chip 7 after overflowing. When brushing the welding layer 4, since the area of ​​the welding layer 4 does not exceed the upper surface area of ​​the electrode pad 1, the area of ​​the welding layer 4 is limited. While controlling the amount of the welding layer 4, a certain distance is reserved to slow down the overflow of the welding layer 4, thereby preventing the welding layer 4 from overflowing to the side of the electrode pad 1 in large quantities. Among them, when the area of ​​the welding layer 4 is smaller than the surface area of ​​the electrode pad 1, the distance between each edge of the welding layer 4 and each edge of the corresponding electrode pad 1 does not exceed 50um, thereby reducing the bonding stress between the pad and the chip electrode, thereby reducing the damage of the welding layer to the chip electrode during the welding process.

[0056] The substrate assembly 2 includes a metal heat sink 22, an insulating layer 21 and a copper circuit layer 5, wherein the insulating layer 21 is arranged on the upper surface of the metal heat sink 22, and the copper circuit layer 5 is arranged on the upper surface of the insulating layer 21. By arranging the metal heat sink 22 and coating the insulating layer 21 on the upper surface of the metal heat sink 22, the entire substrate assembly 2 has good thermal conductivity; or

[0057] As the instruction manual Figure 3 As shown, the substrate assembly 2 includes an insulating substrate 23 and a copper circuit layer 5, and the copper circuit layer 5 is arranged on the upper surface of the insulating substrate 23. By replacing the substrate assembly 2 with a metal heat sink with an insulating substrate 23, the insulating substrate 23 is an alumina ceramic substrate or an aluminum nitride ceramic substrate, which can ensure good electrical insulation performance while also having a certain thermal conductivity, and can also reduce the process of covering the insulating layer 21.

[0058] In this embodiment, the thickness of the copper circuit layer 5 is less than the height of the electrode pad, and the thickness of the copper circuit layer 5 is 30 μm. The following method is required to prepare the copper circuit layer 5:

[0059] Method 1:

[0060] a: Select a copper foil with the same thickness as electrode pad 1;

[0061] b: making a mask to cover the electrode pad 1 and corroding the copper foil until the copper foil reaches the preset thickness of the copper circuit layer 5;

[0062] c) removing the first mask and making a second mask to cover the electrode pad 1 and part of the copper circuit layer 5 obtained in step b, exposing the position of the copper circuit layer 5 not blocked by the mask, that is, the position without copper layer in the preset copper circuit layer 5, and etching it;

[0063] d: Remove the second mask to produce the electrode pad 1 and the copper circuit layer 5.

[0064] Method 2:

[0065] e: Select a copper foil with a thickness consistent with the preset copper circuit layer 5;

[0066] f: making a mask to block the electrode pad 1 and part of the copper foil, exposing the position of the copper foil not blocked by the mask, that is, the position without copper layer in the preset copper circuit layer 5, and etching it;

[0067] g: Remove the third mask, make a fourth mask and cover it on the copper foil to expose the copper foil at the corresponding position of the electrode pad 1;

[0068] h: thickening the copper foil at the electrode pad 1 position to a preset thickness of the electrode pad 1 by evaporation or electroplating;

[0069] i: Remove mask 4 to produce electrode pad 1 and copper circuit layer 5.

[0070] Among them, the method for making the mask is an existing conventional technology, so it will not be described in detail here. Among them, the etching method for the thick copper foil can be wet etching with a solution, or dry etching with a plasma bombardment device. The plasma bombardment device can be a plasma etcher, and the etching solution can be a potassium hydroxide solution or a mixture of hydrofluoric acid, nitric acid and acetic acid (HNA). The specific etching or etching method is an existing conventional technical solution, so it will not be described in detail here.

[0071] Multiple groups of electrode pads 1 are arranged at intervals along the copper circuit layer 5, and the copper circuit layer 5 also includes multiple connection areas. The lower end of the electrode pad 1 is assembled on the connection area and is electrically connected to the copper circuit layer 5. The upper end thereof passes through the reflective white glue layer 6 and is electrically connected to the chip 7 through the welding layer. The width of the connection area is not less than the width of the electrode pad 1, and the length of the connection area is not less than half the length of the chip 7. By arranging multiple groups of electrode pads 1 at intervals on the copper circuit layer 5, the corresponding chips 7 are also installed at intervals along the copper circuit layer 5 and connected in series with each other. At the same time, when facing a chip with higher power, since the length and width of the copper circuit layer 5 between two adjacent groups of electrode pads 1 are limited, the copper circuit layer 5 is used for auxiliary heat dissipation, which increases the heat dissipation area of ​​the entire circuit and improves the heat dissipation capacity of the entire copper circuit layer 5.

[0072] In this embodiment, when the layout of chip 7 is designed for high power density on a high thermal conductivity insulating substrate due to actual working conditions, for example, if the gap between adjacent chips 7 is small, the length of the connection area cannot be guaranteed to be no less than half the length of the chip 7, and it is also possible to only ensure that the width of the connection area is no less than the width of the electrode pad 1.

[0073] The height of the copper electrode pad is not less than 80um, the thickness of the electrode pad 1 is greater than the thickness of the copper circuit layer 5, and the difference between the thickness of the electrode pad 1 and the thickness of the copper circuit layer 5 is not less than 30um. Since the thicker the copper circuit layer 5, the higher the cost and the worse the heat dissipation of the chip, the thickness of the copper circuit layer 5 does not exceed 300um. The welding layer 4 can be solder paste, conductive silver glue, etc., and the chip 7 is welded to the electrode pad 1 through the welding layer 4 by welding methods such as reflow and high-temperature baking.

[0074] In this embodiment, the height of the electrode pad 1 is 80um, the thickness of the white glue layer is 100um, the thickness of the welding layer 4 is 20um, and the thickness of the copper circuit layer is 30um. This can not only ensure the uniform thickness of the reflective white glue layer 6, but also have a good covering effect on the electrode pad 1 and the welding layer 4, with low cost and guaranteed luminous effect.

[0075] In other embodiments, the welding layer 4 can also be provided with a eutectic welding material on the chip, such as gold-tin. By placing the chip provided with the welding layer 4 on the electrode pad and fixing the chip by eutectic means, the chip fixing effect can also be achieved. In this embodiment, the thickness of the welding layer 4 does not exceed 5um.

[0076] It also includes a phosphor glue layer 3, which is laid in the light source area and covers the top of the plurality of chips 7. By setting the phosphor glue layer 3, the phosphor glue layer 3 has high transmittance, high refractive index, good thermal stability and low stress. It can ensure the luminous effect of the device when emitting light through light conversion and self-optimization.

[0077] In this embodiment, the phosphor glue layer 3 is specifically a mixture of phosphor and a colloid material, wherein the colloid can be a silicone elastomer. The two can be mixed by mixing, that is, the phosphor and the encapsulating glue are evenly mixed, or by settling, that is, the phosphor is allowed to settle to the bottom of the colloid material through centrifugation or gravity.

[0078] It also includes two light source pads 9, which are assembled on the substrate assembly 2 and located outside the light source area. The two light source pads 9 are electrically connected to the copper circuit layer 5. By electrically connecting the two light source pads 9 to the positive and negative poles of an external device, which may be a power supply device, respectively, the device can achieve high light efficiency.

[0079] In this embodiment, a layer of white oil may be coated on the entire insulating layer 21 except for the electrode pad position, or a layer of white oil may be provided only on the outer edge of the light source area.

[0080] A second object of the present invention is to provide a packaging method for a flip-chip COB light source with high light efficiency.

[0081] In order to achieve the above objectives, the technical solutions of this application are as follows:

[0082] A packaging method for a high-light-efficiency flip-chip COB light source comprises the following steps:

[0083] Step 1: Set a light source area on the substrate, and set a copper circuit layer 5 inside the light source area, and set a plurality of electrode pads 1 along the copper circuit layer 5, wherein the light source area is formed by enclosing a dam glue 8 that has been baked and cured, or by setting a groove on the substrate to form the light source area;

[0084] Step 2: Set a soldering layer 4 on each electrode pad 1 and fix the chip 7 on the soldering layer 4. When fixing the direction of the chip 7, it is necessary to fix the chip 7 in the prescribed positive and negative directions, while ensuring that the bottom electrode pad 1 and the overflowing soldering layer 4 are blocked by the chip 7 so as not to be exposed;

[0085] Step 3: Lay a reflective white glue layer 6 in the gaps between the multiple electrode pads 1 in the light source area, so that it covers each electrode pad 1 and the solder layer provided on the electrode pad 1. When covering, ensure that the reflective white glue layer 6 does not exceed the lower surface of the chip 7 to avoid blocking the side light of the chip 7;

[0086] Step 4: Lay the phosphor glue layer 3 on the high-reflective white glue layer 6 and encapsulate it, wherein the thickness of the dam glue 8 is not lower than the upper surface of the phosphor glue layer 3, or;

[0087] The upper surface of the phosphor glue layer 3 is at the same level as the notch of the sink.

[0088] To sum up, the present application uses the method of first fixing the chip 7 and then applying glue to fill the reflective white glue layer 6 in the gap between the chips 7. By controlling the height, laying position and shape of the reflective white glue layer 6 after laying, it can avoid the adverse effects of white oil, welding layer 4, electrode pad 1 and other structures on the light-emitting effect of the chip 7 in the conventional packaging method without affecting the normal light emission of the chip 7.

[0089] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A high-efficiency flip-chip COB light source, characterized in that: include: A substrate assembly (2), wherein a light source area is provided on the substrate assembly (2), a reflective white glue layer (6) is laid inside the light source area, a plurality of groups of electrode pads (1) are provided on the substrate assembly (2), and a welding layer (4) is provided on each of the plurality of groups of electrode pads (1); and A plurality of chips (7), each of the chips (7) is arranged on each group of the electrode pads (1) in a one-to-one correspondence and is welded to the electrode pads (1) via a welding layer (4); the height of the reflective white glue layer (6) is located at the position of the lower surface of the chip (7) and is used to fill the gaps between the plurality of the electrode pads (1) and the side walls of the welding layer (4); the reflective white glue layer (6) is provided with a plurality of protrusions for enclosing the connection between the electrode pads (1) and the chip (7).

2. The high-light-efficiency flip-chip COB light source according to claim 1, characterized in that: Each group of electrode pads (1) includes two copper electrode pads arranged at intervals, and the reflective white glue layer (6) is also filled between the two copper electrode pads, and the thickness d of the reflective white glue layer (6) satisfies: 80 um≤d≤300 um.

3. The high-light-efficiency flip-chip COB light source according to claim 1, characterized in that: The light source area is a sink formed on the substrate assembly (2); or It also includes a dam glue (8), and the dam glue (8) is connected end to end to enclose the light source area.

4. The high-light-efficiency flip-chip COB light source according to claim 1, characterized in that: The projection of one end of each group of electrode pads (1) away from the substrate assembly (2) on the substrate assembly (2) is located within the projection area of ​​the corresponding chip (7) on the substrate assembly (2).

5. The high-light-efficiency flip-chip COB light source according to claim 1, characterized in that: The substrate assembly (2) comprises a metal heat sink (22), an insulating layer (21) and a copper circuit layer (5), wherein the insulating layer (21) is arranged on the upper surface of the metal heat sink (22), and the copper circuit layer (5) is arranged on the upper surface of the insulating layer (21); or The substrate assembly (2) comprises an insulating substrate (23) and a copper circuit layer (5), wherein the copper circuit layer (5) is arranged on the upper surface of the insulating substrate (23).

6. The high-light-efficiency flip-chip COB light source according to claim 5, characterized in that: A plurality of groups of electrode pads (1) are arranged at intervals along the copper circuit layer (5), and the copper circuit layer (5) further comprises a plurality of connection areas. The lower ends of the electrode pads (1) are assembled on the connection areas and are electrically connected to the copper circuit layer (5), and the upper ends thereof penetrate the reflective white glue layer (6) and are electrically connected to the chip (7) through the welding layer. The width of the connection areas is not less than the width of the electrode pads (1), and the length of the connection areas is not less than half the length of the chip (7).

7. The high-light-efficiency flip-chip COB light source according to claim 6, characterized in that: The height of the electrode pad (1) is not less than 80 μm, the thickness of the electrode pad (1) is greater than the thickness of the copper circuit layer (5), and the difference between the thickness of the electrode pad (1) and the thickness of the copper circuit layer (5) is not less than 30 μm.

8. A high-light-efficiency flip-chip COB light source according to any one of claims 1 to 7, characterized in that: It also includes a phosphor glue layer (3), which is laid in the light source area and covers the top of the plurality of chips (7).

9. The high-light-efficiency flip-chip COB light source according to claim 7, characterized in that: It also includes two light source soldering pads, which are mounted on the substrate assembly (2) and located outside the light source area. Both of the light source soldering pads are electrically connected to the copper circuit layer (5).

10. A packaging method for a high-light-efficiency flip-chip COB light source, characterized by: The following steps are involved: Step 1: setting a light source area on the substrate, setting a copper circuit layer (5) inside the light source area, and setting a plurality of electrode pads (1) along the copper circuit layer (5); Step 2: providing a welding layer on each electrode pad (1) and fixing the chip (7) on the welding layer; Step 3: Laying a reflective white glue layer (6) in the gaps between the plurality of electrode pads (1) in the light source area, so as to cover each electrode pad and the welding layer provided on the electrode pad; Step 4: Lay the phosphor glue layer (3) on the high-reflective white glue layer (6) and encapsulate it.

Images