LED with surface light emitting characteristic and preparation method thereof

Abstract

The invention discloses an LED with a surface light emitting characteristic, which comprises a packaging bracket, an LED chip, a fluorescent glue layer and a color dispersing glue layer, the LED chip is arranged on the packaging bracket, the fluorescent glue layer covers the LED chip, the color dispersing glue layer is positioned above the fluorescent glue layer, the fluorescent glue layer is formed by curing silica gel or epoxy resin containing fluorescent powder particles, and the color dispersing glue layer is positioned above the fluorescent glue layer. The color scattering glue layer is formed after silica gel containing color scattering particles or epoxy resin is cured, the top of the fluorescent glue layer is provided with a rhombic protruding structure, the rhombic protruding structure can enable two different glue layers to be combined more tightly, meanwhile, the rhombic protruding structure can also play a role in increasing the light emitting angle, and after blue light emitted by the LED chip passes through the fluorescent glue layer, the light emitting angle of the LED chip can be increased. And white spot light is formed and then diffused by the light diffusing adhesive layer to form surface light with uniform brightness, so that a spot light source can be converted into a surface light source, and the emitted light is uniform and soft.

Description

Technical Field

[0001] The present invention relates to the technical field of LED light sources, and particularly relates to an LED with surface light-emitting characteristics and a preparation method thereof. Background Art

[0002] Most of the emitted light of SMD light-emitting diodes is concentrated at the center position of the LED, resulting in a large central light intensity, a small peripheral light intensity, and a small emission angle, thus presenting a point light source. However, when used as a backlight source, it is necessary to scatter the light emitted by the LED so that the light is evenly distributed over the entire light-emitting surface of the LED. Generally, a lens and a diffuser plate are provided on the surface of the LED in the backlight module to scatter the light emitted by the LED. However, the center of the lens needs to be aligned with the center of the LED, otherwise there will be problems such as light leakage and uneven light color and brightness. Moreover, the lens or diffuser plate is relatively thick, which will increase the overall thickness of the product while improving the light emission uniformity; in addition, in order to avoid the phenomenon of uneven light brightness in the backlight module, it is also necessary to increase the LED in the dark area, thereby increasing the number of LEDs used and increasing the overall cost. Summary of the Invention

[0003] In view of the above problems, the present invention discloses an LED with surface light-emitting characteristics and a preparation method thereof, which can convert a point light source into a surface light source, and solves the problems of uneven light emission and small emission angle of the point light source in the prior art.

[0004] The specific technical solutions are as follows:

[0005] An LED with surface light-emitting characteristics includes a packaging bracket, an LED chip, a fluorescent glue layer, and a scattering glue layer. The LED chip is installed in the cup of the packaging bracket. The fluorescent glue layer is filled in the cup of the packaging bracket and covers the LED chip. The scattering glue layer covers the upper part of the fluorescent glue layer. The fluorescent glue layer is formed by curing silica gel or epoxy resin containing phosphor particles. The scattering glue layer is formed by curing silica gel or epoxy resin containing scattering particles; several convex structures are provided on the top of the fluorescent glue layer, and a groove structure corresponding to the convex structure is formed at the bottom of the scattering glue layer.

[0006] Further, several of the convex structures are all strip-shaped and arranged in a row.

[0007] Further, the cross-section of the convex structure is a rhombus, a rectangle, a circle or other geometric shapes.

[0008] Further, the LED chip is a blue light chip with a main wavelength of 450-475nm.

[0009] Further, on both sides of the bottom of the encapsulation bracket, a first bracket electrode and a second bracket electrode are respectively provided, and the first bracket electrode and the second bracket electrode are respectively connected to the positive electrode and the negative electrode of the LED chip.

[0010] Further, the fluorescent glue layer is silica gel containing fluorescent powder particles. Correspondingly, the scattering glue layer is silica gel containing scattering particles.

[0011] Further, the fluorescent glue layer is epoxy resin containing fluorescent powder particles. Correspondingly, the scattering glue layer is epoxy resin containing scattering particles.

[0012] Further, the scattering particles are one or more of BaSO4, CaCO3, Al2O3, TiO2, SiO2, polystyrene microspheres (PS), polymethyl methacrylate (PMMA), and silicone microspheres.

[0013] Based on the above content, the present invention also provides a preparation method of an LED with surface light-emitting characteristics, which specifically includes the following steps:

[0014] Step 1: Die bonding. On a die bonder, use conductive glue or non-conductive glue to bond the LED chip in the cup of the encapsulation bracket.

[0015] Step 2: Wire bonding. On an ultrasonic wire bonder, use bonding wires to connect the first and second bracket electrodes to the positive and negative electrodes of the LED chip respectively.

[0016] Step 3: Compression molding. Mix A glue, B glue, and fluorescent powder in a certain proportion, mix them evenly and degas to make fluorescent glue, inject it into a compression molding machine, and preliminarily cure the fluorescent glue on the LED chip in a hot pressing and molding manner. After curing and molding, demold to form a fluorescent glue layer with a convex structure.

[0017] Step 4: Dispensing. Mix A glue, B glue, and scattering particles in a certain proportion, mix them evenly and degas to make scattering glue, inject it into the glue cylinder of a dispenser, and dispense until it is flush with the top of the cup of the encapsulation bracket.

[0018] Step 5: Curing. Put the encapsulation bracket in Step 4 into an oven to cure the scattering glue to form a scattering glue layer.

[0019] Step 6: Testing. Use an optoelectronic parameter tester to test the finished LED, and retain the qualified finished LED.

[0020] Further, in Step 3, the fluorescent powder is composed of yellow-red powder and red powder, and A glue, B glue, yellow-green powder, and red powder are mixed evenly in a ratio of 1.5:1.5:0.4 - 1.3:0.1 - 0.2; in Step 4, A glue, B glue, and scattering particles are mixed evenly in a ratio of 1.5:1.5:0.5 - 1.5.

[0021] Further, in the fifth step, when the diffusing glue is cured, it is cured in segments. The curing temperature of the first segment is 100 °C and the curing time is 30 minutes; the curing temperature of the second segment is 130 °C and the curing time is 60 minutes; the curing temperature of the third segment is 150 °C and the curing time is 180 minutes.

[0022] The beneficial effects of the present invention are reflected in:

[0023] (1) For the LED with surface light-emitting characteristics manufactured by the present invention, after the blue light emitted by the LED chip passes through the fluorescent glue layer, white dot light is formed, and then through the diffusion of the diffusing glue layer, surface light with uniform brightness is formed, so that the point light source can be converted into a surface light source, and the light output is uniform and soft.

[0024] (2) There is a diamond-shaped convex structure on the top of the fluorescent glue layer, which can make the combination of two different glue layers closer and has high reliability.

[0025] (3) The diamond-shaped convex structure on the top of the fluorescent glue layer can increase the light-emitting angle, thereby increasing the irradiation area of the surface light source. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a top view of Embodiment 1 of the present invention.

[0027] Figure 2 It is a schematic structural diagram of Embodiment 1 of the present invention.

[0028] Figure 3 It is a schematic structural diagram of Embodiment 2 of the present invention.

[0029] Figure 4 It is a schematic structural diagram of Embodiment 3 of the present invention.

[0030] Description of the reference numerals: 1, encapsulation bracket; 2, LED chip; 3, diffusing glue layer; 4, fluorescent glue layer; 101, bracket electrode one; 102, bracket electrode two; 301, mixed glue layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] To make the technical solutions of the present invention clearer and more definite, the present invention will be further described below with reference to the accompanying drawings. Any solution obtained by equivalent substitution of the technical features of the technical solutions of the present invention and conventional reasoning falls 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, and welding, bolt-nut connection and screw connection can all be used.

[0032] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is 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 orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0033] Embodiment 1

[0034] Please refer to the attached Figures 1-4 , this embodiment provides an LED with surface light-emitting characteristics, including a packaging bracket, an LED chip, a fluorescent glue layer, and a scattering glue layer. The LED chip is installed in the cup of the packaging bracket. The fluorescent glue layer is filled in the cup of the packaging bracket and covers the LED chip. The scattering glue layer covers the upper part of the fluorescent glue layer. The fluorescent glue layer is formed after the curing of silica gel containing phosphor particles, and the scattering glue layer is formed after the curing of silica gel containing scattering particles. A number of diamond-shaped convex structures are provided on the top of the fluorescent glue layer. The number of diamond-shaped convex structures is all strip-shaped and arranged, and grooves corresponding to the diamond-shaped convex structures are formed at the bottom of the scattering glue layer.

[0035] In this embodiment, the fluorescent glue layer is silica gel containing phosphor particles, and the scattering glue layer is silica gel containing scattering particles. The scattering particles are one or more of BaSO4, CaCO3, Al2O3, TiO2, SiO2, polystyrene microspheres (PS), polymethyl methacrylate (PMMA), and silicone microspheres. Through the dispersion and refraction of scatterers such as microspheres and microbeads, the diffusion of light is realized. The light uniformity and brightness of the product can be improved. The action principle of the scattering glue layer is mainly based on the scattering and refraction of light. By controlling the addition ratio, the diffusion degree of light can be adjusted.

[0036] In this embodiment, the LED chip used is a blue light chip with a main wavelength of 450 - 475 nm. When the blue light emitted by the LED chip passes through the fluorescent glue layer, white point light is formed, and then through the diffusion of the diffusing glue layer, surface light with uniform brightness is formed.

[0037] In this embodiment, on both sides of the bottom of the packaging bracket, a bracket electrode one and a bracket electrode two are respectively provided. The bracket electrode one and the bracket electrode two are respectively connected to the positive and negative electrodes of the LED chip. The LED chip uses a blue light chip with a main wavelength of 450 - 475 nm.

[0038] In this embodiment, the phosphor particles are composed of a mixture of yellow-green powder and red powder. The model of the yellow-green powder is Mitsubishi Chemical BG-201B of Japan, and the model of the red powder is Mitsubishi Chemical BR-101A of Japan. Since it is prior art, it will not be elaborated here.

[0039] The following is the manufacturing method of the LED with surface light-emitting characteristics in this embodiment:

[0040] Step 1: Die bonding. On a die bonder, use conductive or non-conductive adhesive to bond the LED chip in the cup of the packaging bracket.

[0041] Step 2: Wire bonding. On an ultrasonic wire bonder, use bonding wires to connect the first and second bracket electrodes to the positive and negative electrodes of the LED chip respectively.

[0042] Step 3: Compression molding. Mix component A silicone, component B silicone, yellow-green powder, and red powder in a ratio of 1.5:1.5:(0.4 - 1.3):(0.1 - 0.2), mix evenly and degas to make the fluorescent glue, inject it into a liquid vacuum compression molding machine, and preliminarily cure the fluorescent glue on the LED chip in a hot pressing and molding manner. After curing and molding, demold to form a fluorescent glue layer with a diamond-shaped convex structure.

[0043] Step 4: Dispensing. Mix component A silicone, component B silicone, and scattering particles in a ratio of 1.5:1.5:(0.5 - 1.5), mix evenly and degas to make the scattering glue, inject it into the glue cylinder of the dispenser, and dispense until it is flush with the top of the cup of the packaging bracket.

[0044] Step 5: Curing. Put the packaging bracket in step 4 into an oven to cure the scattering glue to form a scattering glue layer; when curing the scattering glue, use segmented 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.

[0045] Step 6: Testing. Use an optoelectronic parameter tester to test the finished LED, and retain the qualified finished LED.

[0046] In this embodiment, the models of component A silicone and component B silicone in step 3 are: Dow Corning OE-7340A and OE-7340B.

[0047] Embodiment 2

[0048] Please refer to the attached Figure 3 As shown, an LED with surface light-emitting characteristics includes a packaging bracket, an LED chip, a fluorescent glue layer, and a scattering glue layer. The LED chip is installed in the cup of the packaging bracket. The fluorescent glue layer is filled in the cup of the packaging bracket and covers the LED chip. The scattering glue layer covers the upper part of the fluorescent glue layer. There are several wavy convex structures on the top of the fluorescent glue layer. The several wavy convex structures are all strip-shaped and arranged in a row, and grooves corresponding to the wavy convex structures are formed at the bottom of the scattering glue layer.

[0049] In this embodiment, the fluorescent glue layer is formed after the curing of an epoxy resin containing phosphor particles, and the scattering glue layer is formed after the curing of an epoxy resin containing scattering particles.

[0050] The following is the manufacturing method of the LED with surface light-emitting characteristics in this embodiment:

[0051] Step 1: Die bonding. On a die bonder, use conductive glue or non-conductive glue to bond the LED chip in the cup of the encapsulation bracket.

[0052] Step 2: Wire bonding. On an ultrasonic wire bonder, use bonding wires to connect the bracket electrodes and the LED chip electrodes respectively.

[0053] Step 3: Compression molding. Mix epoxy resin A glue, epoxy resin B glue, yellow-green powder, and red powder in a ratio of 1.5:1.5:(0.4 - 1.3):(0.1 - 0.2), mix evenly and degas to make fluorescent glue, inject it into a compression molding machine, and preliminarily cure the fluorescent glue on the LED chip in a hot pressing and molding manner. After curing and molding, demold to form a fluorescent glue layer with a wavy convex structure.

[0054] Step 4: Dispensing. Mix epoxy resin A glue, epoxy resin B glue, and scattering particles in a ratio of 1.5:1.5:(0.5 - 1.5), mix evenly and degas to make scattering glue, inject it into a compression molding machine, and demold after curing and molding to form a scattering glue layer with a flat surface.

[0055] Step 6: Testing. Use an optoelectronic parameter tester to test the finished LED, and retain the qualified finished LED.

[0056] Embodiment 3

[0057] Please refer to the attached Figure 4 As shown, an LED with surface light-emitting characteristics includes an encapsulation bracket, an LED chip, and a mixed glue layer. The LED chip is installed in the cup of the encapsulation bracket, and the mixed glue layer covers the LED chip. The mixed glue layer is a mixed glue containing phosphor particles, scattering particles, and silica gel.

[0058] The following is the manufacturing process of the LED with surface light-emitting characteristics in this embodiment:

[0059] Step 1: On a die bonder, use conductive glue or non-conductive glue to bond the LED chip in the cup of the encapsulation bracket;

[0060] Step 2: On an ultrasonic wire bonder, use bonding wires to connect the bracket electrodes and the LED chip electrodes.

[0061] Step 3: Mix the silicone of Component A, the silicone of Component B, the scattering particles, and the phosphor particles evenly in a ratio of 3:3:(0.5 - 1.5):(0.5 - 1.5), and defoam. Then inject the mixture into the cartridge of the dispensing machine and dispense until it is level with the top of the cup of the encapsulation bracket.

[0062] Step 4: Place the above encapsulation bracket into an oven to cure the mixed glue. The curing of the mixed glue is carried out in stages. The curing temperature in the first stage is 100 °C and the curing time is 30 minutes; the curing temperature in the second stage is 130 °C and the curing time is 60 minutes; the curing temperature in the third stage is 150 °C and the curing time is 180 minutes.

[0063] Step 5: Test the finished LED using an optoelectronic parameter tester, and retain the qualified finished LEDs.

[0064] As described above, it is only the 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 those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. An LED having a surface emitting characteristic, characterized in that: It includes a packaging bracket, an LED chip, a fluorescent glue layer, and a scattered color glue layer. The LED chip is installed in the bowl of the packaging bracket, the fluorescent glue layer is filled in the bowl of the packaging bracket and covers the LED chip, the scattered color glue layer covers the fluorescent glue layer, the fluorescent glue layer is formed by curing silicone or epoxy resin containing fluorescent particles, and the scattered color glue layer is formed by curing silicone or epoxy resin containing scattered color particles; a plurality of protruding structures are provided on the top of the fluorescent glue layer, and a groove structure corresponding to the protruding structure is formed at the bottom of the scattered color glue layer.

2. The LED with surface emitting characteristics as claimed in claim 1, characterized in that: The plurality of protruding structures are all in the shape of long strips and are arranged in an array.

3. The LED with surface emitting characteristics as claimed in claim 2, characterized in that: The cross section of the protruding structure is a diamond, rectangle, circle or other geometric shapes.

4. The LED with surface emitting characteristics as claimed in claim 1, characterized in that: The LED chip is a blue light chip with a main wavelength of 450-475nm.

5. The LED with surface emitting characteristics as claimed in claim 1, characterized in that: The fluorescent adhesive layer is silica gel containing fluorescent powder particles, and correspondingly, the scattered color adhesive layer is silica gel containing scattered color particles.

6. The LED with surface emitting characteristics as claimed in claim 1, characterized in that: The fluorescent adhesive layer is an epoxy resin containing fluorescent powder particles, and correspondingly, the scattered color adhesive layer is an epoxy resin containing scattered color particles.

7. The LED with surface emitting characteristics as claimed in claim 1, characterized in that: The scattered color particles are one or more of BaSO4, CaCO3, Al2O3, TiO2, SiO2, polystyrene microspheres (PS), polymethyl methacrylate (PMMA), and silicone microspheres.

8. A method for preparing an LED having a surface emitting characteristic as claimed in any one of claims 1 to 6, characterized in that: The specific steps include: Step 1: Die bonding: On the die bonding machine, use conductive glue or non-conductive glue to bond the LED chip in the bowl of the package bracket; Step 2: Wire bonding: On an ultrasonic wire bonding machine, use bonding wires to connect the first and second electrodes of the bracket to the positive and negative electrodes of the LED chip respectively; Step 3: molding, mixing glue A, glue B and phosphor in a certain proportion and degassing to make fluorescent glue, injecting into the molding machine, making the fluorescent glue initially solidify on the LED chip by hot pressing molding, demolding after solidification, and forming a fluorescent glue layer with a convex structure; Step 4: Glue dispensing: mix glue A, glue B and scattered color particles in a certain proportion and degas to make scattered color glue, inject it into the glue cylinder of the glue dispensing machine, and dispense the glue until it is level with the top of the packaging bracket bowl; Step 5: Curing: putting the package bracket in step 4 into a baking oven to cure the dispersed color glue to form a dispersed color glue layer; Step 6: Testing: Use a photoelectric parameter tester to test the finished LEDs, and keep the finished LEDs that pass the test.

9. The method for preparing a LED having a surface emitting characteristic as claimed in claim 7, characterized in that: In the step three, the fluorescent powder is composed of yellow-red powder and red powder, and A glue, B glue, yellow-green powder and red powder are evenly mixed in a ratio of 1.5:1.5:(0.4-1.3):(0.1-0.2); in the step four, A glue, B glue and scattered color particles are evenly mixed in a ratio of 1.5:1.5:(0.5-1.5).

10. The method for preparing a LED having a surface emitting characteristic according to claim 7, characterized in that: In step 5, the dispersed color glue is cured in sections, with the first section curing temperature being 100° C. and the curing time being 30 minutes; the second section curing temperature being 130° C. and the curing time being 60 minutes; and the third section curing temperature being 150° C. and the curing time being 180 minutes.

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