A kind of ultraviolet LED packaging structure and preparation method thereof

Abstract

The present invention belongs to the technical field of semiconductor packaging, and discloses an ultraviolet LED packaging structure, including: an LED bracket, an ultraviolet LED chip, an adhesive layer and inorganic glass, and the LED bracket is connected to the inorganic glass through the adhesive layer to realize the sealing function. Among them: the adhesive layer includes an organic adhesive module, an ultraviolet light absorber module and a desiccant module, the organic adhesive module connects the LED bracket to the inorganic glass, the ultraviolet light absorber module is used to block the ultraviolet light emitted by the ultraviolet LED chip from the aging and decay of the organic adhesive, and the desiccant module is used to block the water vapor component of the external air environment to protect the ultraviolet LED chip from being affected. The present invention solves the aging problem of the organic adhesive in the ultraviolet LED packaging structure that is easily affected by ultraviolet light irradiation and the failure problem of the ultraviolet LED chip that is easily affected by air water vapor, and effectively improves the stability of the ultraviolet LED. The present invention also provides a method for preparing an ultraviolet LED packaging structure.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor packaging, and in particular to an ultraviolet LED packaging structure and a preparation method thereof. Background Art

[0002] In order to protect the global ecological environment, the mercury lamp ultraviolet light source that originally occupied the main market will gradually withdraw from the historical stage, and will be replaced by environmentally friendly and energy-saving ultraviolet LED solid-state light sources. This is an important historical development opportunity for the ultraviolet LED industry. Ultraviolet LED mainly refers to a type of LED with a wavelength shorter than 410nm. According to its wavelength, it can be divided into three categories: (1) near ultraviolet (UVA): 410-320nm, (2) mid-ultraviolet (UVB): 320-280nm, (3) deep ultraviolet (UVC): 280-100nm. Ultraviolet LEDs with different emission wavelengths have different application occasions and have huge market potential. Near ultraviolet LEDs (UVA-LEDs) are mainly used in full-spectrum lighting, ultraviolet curing, banknote anti-counterfeiting identification, color conversion, 3D printing and ink printing; mid-ultraviolet LEDs (UVB-LEDs) are mainly used in plant growth, photocatalysis, environmental purification and medical applications; deep ultraviolet LEDs (UVC-LEDs) are mainly used in sterilization, water purification, sensors and even photoionization. At present, the disinfection and sterilization effect of short-wavelength ultraviolet LEDs has attracted widespread attention.

[0003] Packaging is an important link that affects the performance of LED devices. For white light LED devices, organic packaging colloids are usually filled on the surface of the LED chip to seal and protect the LED chip from interference from the external water vapor environment. However, for short-wavelength ultraviolet LED chips, due to the long-term exposure to ultraviolet rays, the organic polymer absorbs ultraviolet photons with large energy, resulting in the destruction of the bond chains between the organic polymers, which easily causes the organic packaging colloid to age and decay, affecting the performance of the ultraviolet LED device. In order to improve the stability of ultraviolet LED devices, the use of inorganic glass packaging has become a hot topic in research. Inorganic glass is placed on the top of the ultraviolet LED to prevent damage to the ultraviolet LED chip from the external environment. However, since inorganic glass cannot be directly connected to the LED bracket, the common practice is to add an organic adhesive in the middle, such as silica gel, polydimethylsiloxane (PDMS), etc. The addition of organic adhesives solves the difficulty of connecting inorganic glass to the LED bracket, and the process is simple and suitable for large-scale industrialization. However, under long-term ultraviolet irradiation, organic adhesives will also have ultraviolet aging and degradation problems, resulting in the use dilemma of organic adhesives deforming or even falling off. In addition, due to the lack of organic packaging colloids similar to those used in white light LED device packaging, the UV LED chip is directly exposed to the air environment and is easily corroded by the water vapor environment in the air and fails. Therefore, how to design a low-cost, stable and reliable UV LED packaging structure is still a technical problem that the industry needs to solve. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides an ultraviolet LED packaging structure.

[0005] The invention also provides a method for preparing an ultraviolet LED packaging structure.

[0006] An ultraviolet LED packaging structure of the present invention is implemented by the following technical solution:

[0007] A UV LED packaging structure comprises: an LED bracket, a UV LED chip, an adhesive layer and inorganic glass; the LED bracket is arranged on a bottom layer; the UV LED chip is arranged on the upper surface of an inner cavity of the LED bracket, and the UV LED chip is connected to a through-hole metal circuit in the inner cavity of the LED bracket; the adhesive layer is arranged on the top surface of the LED bracket, and connects the LED bracket to the inorganic glass to achieve sealing; the inorganic glass is arranged on the top of the UV LED, and the lower surface of the inorganic glass is connected to the upper surface of the adhesive layer.

[0008] Preferably, the width of the adhesive layer is consistent with the width of the edge of the top surface of the LED bracket, and includes: an organic adhesive module, an ultraviolet absorber module and a desiccant module. The organic adhesive module connects the LED bracket to the inorganic glass. The ultraviolet absorber module is used to block the aging and degradation effects of the ultraviolet light emitted by the ultraviolet LED chip on the organic adhesive. The desiccant module is used to block the water vapor components of the external air environment to protect the ultraviolet LED chip from being affected by it.

[0009] Preferably, the organic adhesive module, the ultraviolet absorber module and the desiccant module are connected side by side with the same height, and the organic adhesive module is placed in the outermost layer, including from the outside to the inside: two combinations of organic adhesive module / ultraviolet absorber module / desiccant module and organic adhesive module / desiccant module / ultraviolet absorber module, wherein: the width of the organic adhesive module accounts for 1 / 3-2 / 3 of the adhesive layer, the width of the ultraviolet absorber module accounts for 1 / 6-1 / 3 of the adhesive layer, and the width of the desiccant module accounts for 1 / 6-1 / 3 of the adhesive layer.

[0010] Preferably, the organic adhesive module includes one or a combination of silica gel and polydimethylsiloxane (PDMS) materials; the ultraviolet absorber module is formed by mixing PDMS and ultraviolet absorbing particles in a certain mass ratio, and the ultraviolet absorbing particles include one or a combination of zinc oxide (ZnO), titanium dioxide (TiO2), and iron oxide (Fe2O3), with a mass concentration of 5-25wt%; the desiccant module is formed by mixing PDMS and dry particles in a certain ratio, and the dry particles include calcium oxide (CaO), anhydrous calcium chloride (CaCl2), aluminum oxide (Al2O3), calcium sulfate (CaSO4), and sodium sulfate (Na2SO4), with a mass concentration of 5-25wt%.

[0011] Preferably, the LED bracket is provided with an inner cavity through-hole metal circuit, which is divided into positive and negative poles, the positive pole of the through-hole metal circuit is connected to the positive pole of the ultraviolet LED chip, and the negative pole of the through-hole metal circuit is connected to the negative pole of the ultraviolet LED chip; the inner cavity surface of the LED bracket is provided with a metal reflective layer, and the metal reflective layer is composed of aluminum or silver, and the reflectivity is 50-90%.

[0012] Preferably, the ultraviolet LED chip is rectangular in shape, has a light emission wavelength of 250-410 nm, and a height of 50-200 μm.

[0013] Preferably, the shape of the inorganic glass is consistent with the bottom shape of the LED bracket, and the height is 0.5-3 mm.

[0014] The preparation method of a UV LED packaging structure of the present invention is implemented by the following technical solution:

[0015] A method for preparing an ultraviolet LED packaging structure comprises the following steps:

[0016] S1. Crystal bonding: Use a crystal bonding machine to fix the UV LED chip at the center of the upper surface of the LED bracket cavity;

[0017] S2. Electrical connection: connect the UV LED chip to the metal circuit inside the LED bracket;

[0018] S3. Prepare an organic binder, a UV absorber, and a desiccant, wherein the UV absorber is formed by mixing PDMS and UV absorbing particles in a certain mass ratio and subjected to vacuum degassing; the desiccant is formed by mixing PDMS and dry particles in a certain ratio and subjected to vacuum degassing;

[0019] S4. Printing adhesive layer: using a template printing method, printing an organic adhesive, an ultraviolet absorber, and a desiccant on the surface of the inorganic glass to form an organic adhesive module, an ultraviolet absorber module, and a desiccant module, and the organic adhesive module, the ultraviolet absorber module, and the desiccant module together constitute an adhesive layer;

[0020] S5. Connecting: placing the inorganic glass obtained in step S4 upside down on the top surface of the LED bracket, wherein the lower surface of the adhesive layer is connected to the top surface of the LED bracket, and the four sides of the inorganic glass are aligned with the four sides of the LED bracket;

[0021] S6. Heat and cure to complete the packaging process.

[0022] Preferably, in step S4, the organic adhesive is printed on the surface of the inorganic glass by an organic adhesive printing template, the ultraviolet absorber is printed on the surface of the inorganic glass by an ultraviolet absorber printing template, and the desiccant is printed on the surface of the inorganic glass by a desiccant printing template; wherein: the organic adhesive printing template is reserved with an organic adhesive module-shaped through hole, the ultraviolet absorber printing template is reserved with an ultraviolet absorber module-shaped through hole, and the desiccant printing template is reserved with a desiccant module-shaped through hole.

[0023] The sum of the widths of the organic adhesive module-shaped through hole, the ultraviolet light absorber module-shaped through hole and the desiccant module-shaped through hole is consistent with the width of the edge of the top surface of the LED bracket, and the thickness is 0.5-3 mm.

[0024] Preferably, in step S6, the heating curing temperature is 80-180° C. and the time is 1-3 hours.

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0026] (1) The UV LED packaging structure of the present invention solves the aging problem of the organic adhesive in the UV LED packaging structure that is susceptible to UV light irradiation and the failure problem of the UV LED chip that is susceptible to interference from air and water vapor by designing the composition structure of the adhesive layer to prepare an adhesive layer containing an organic adhesive module / UV absorber module / desiccant module, thereby effectively improving the stability of the UV LED.

[0027] (2) The ultraviolet LED packaging structure of the present invention has a simple preparation process and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the UV LED chip being die-bonded on the LED bracket in Example 1 of the present invention;

[0029] Figure 2 This is a schematic diagram of the electrical connection of the ultraviolet LED chip to the metal circuit of the LED bracket in Example 1 of the present invention;

[0030] Figure 3 Schematic diagram of an organic adhesive printing template in Example 1 of the present invention;

[0031] Figure 4 This is a schematic diagram of printing an organic adhesive on inorganic glass in Example 1 of the present invention;

[0032] Figure 5 This is a schematic diagram of a UV absorber printing template in Example 1 of the present invention;

[0033] Figure 6 This is a schematic diagram of printing an ultraviolet light absorber on inorganic glass in Example 1 of the present invention;

[0034] Figure 7 Schematic diagram of a desiccant printing template in Example 1 of the present invention;

[0035] Figure 8 This is a schematic diagram of printing a desiccant on inorganic glass in Example 1 of the present invention;

[0036] Fig. 9 This is a schematic diagram of the UV LED packaging structure after packaging is completed in Example 1 of the present invention;

[0037] Fig.10 This is a schematic diagram of the UV LED packaging structure after packaging is completed in Example 2 of the present invention;

[0038] Fig.11 This is a schematic diagram of the UV LED packaging structure after packaging is completed in Example 3 of the present invention;

[0039] Among them: 1-LED bracket, 2-ultraviolet LED chip, 3-adhesive layer, 31-organic adhesive module, 32-ultraviolet absorber module, 33-desiccant module, 4-inorganic glass, 5-organic adhesive printing template, 6-ultraviolet absorber printing template, 7-desiccant printing template. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0041] Example 1

[0042] A UV LED packaging structure includes: an LED bracket 1, a UV LED chip 2, an adhesive layer 3 and an inorganic glass 4. The LED bracket 1 is placed on the bottom layer; the UV LED chip 2 is placed on the upper surface of the inner cavity of the LED bracket 1, preferably, the UV LED chip 2 is placed at the center of the upper surface of the inner cavity of the LED bracket 1, and the UV LED chip 2 is connected to the through-hole metal circuit of the inner cavity of the LED bracket 1; the adhesive layer 3 is located on the top surface of the LED bracket 1, and connects the LED bracket 1 with the inorganic glass 4 to achieve a sealing function; the inorganic glass 4 is located on the top of the UV LED, and its lower surface is connected to the upper surface of the adhesive layer 3.

[0043] In a preferred embodiment, the width of the adhesive layer 3 is consistent with the width of the edge of the top surface of the LED bracket, including: an organic adhesive module 31, an ultraviolet absorber module 32 and a desiccant module 33, the three are connected side by side with the same height, and the organic adhesive module 31 is placed in the outermost layer, preferably: an organic adhesive module 31 / ultraviolet absorber module 32 / desiccant module 33 combination form, the width of the organic adhesive module accounts for 1 / 2 of the adhesive layer, the width of the ultraviolet absorber module accounts for 1 / 4 of the adhesive layer, and the width of the desiccant module accounts for 1 / 4 of the adhesive layer.

[0044] A method for preparing an ultraviolet LED packaging structure comprises the following steps:

[0045] S1. Select a normal-type UV LED chip 2 with a light emission wavelength of 280nm, a rectangular shape, a size of 45x45mil, and a height of 150μm. Bond the UV LED chip to Figure 1 As shown, a crystal bonding machine is used to fix the ultraviolet LED chip 2 at the center of the upper surface of the inner cavity of the LED bracket 1.

[0046] S2.Electrical connection, such as Figure 2As shown, the LED bracket 1 is provided with a through-hole metal circuit, and a gold ball wire bonding machine is used to weld gold wires to connect the ultraviolet LED chip 2 and the through-hole metal circuit in the inner cavity of the LED bracket 1, wherein the positive electrode of the through-hole metal circuit is connected to the positive electrode of the ultraviolet LED chip 2 through the gold wire, and the negative electrode of the through-hole metal circuit is connected to the negative electrode of the ultraviolet LED chip 2 through the gold wire; a metal reflective layer is provided on the inner cavity surface of the LED bracket 1, and the metal reflective layer is composed of aluminum and has a reflectivity of 70%.

[0047] S3. Prepare an organic adhesive, an ultraviolet light absorber, and a desiccant. The organic adhesive module 31 in the adhesive layer 3 is preferably polydimethylsiloxane (PDMS); the ultraviolet light absorber module 32 is formed by mixing PDMS and ultraviolet light absorbing particles in a certain mass ratio, and the ultraviolet light absorbing particles are preferably zinc oxide (ZnO) with a mass concentration of 10wt%, and are subjected to vacuum degassing treatment, and bubbles are removed by high-speed stirring at a vacuum degree of -20KPa, and the stirring speed is 2000rpm for 6min; the desiccant module 33 is formed by mixing PDMS and dry particles in a certain ratio, and the dry particles are preferably anhydrous calcium chloride (CaCl2) with a mass concentration of 10wt%, and are subjected to vacuum degassing treatment, and bubbles are removed by high-speed stirring at a vacuum degree of -20KPa, and the stirring speed is 2000rpm for 6min.

[0048] S4. Printing the adhesive layer. Using the template printing method, the organic adhesive module 31, the ultraviolet light absorber module 32, and the desiccant module 33 are respectively printed and placed on the surface of the inorganic glass 4 to form the adhesive layer 3. The shape of the inorganic glass 4 is consistent with the bottom shape of the LED bracket 1, both are rectangular, with a size of 3.5 x 3.5 mm and a height of 1.5 mm.

[0049] S41. Figure 3 As shown, the organic adhesive printing template is reserved with an organic adhesive-shaped through hole with a thickness of 2 mm. Figure 4 As shown, the organic adhesive printing template 5 is placed on the surface of the inorganic glass 4, a sufficient amount of organic adhesive is dotted, and the organic adhesive is printed from the through holes of the organic adhesive printing template 5 onto the surface of the inorganic glass 4 using a precision scraper.

[0050] S42. Figure 5 As shown, the UV absorber printing template 6 has a UV absorber-shaped through hole reserved therein, and the thickness is 2 mm. Figure 6 As shown, the UV absorber printing template 6 is placed on the surface of the inorganic glass 4, a sufficient amount of UV absorber 32 is dotted, and the UV absorber is printed from the through holes of the UV absorber printing template 6 onto the surface of the inorganic glass 4 using a precision scraper.

[0051] S43. Figure 7As shown, the desiccant printing template 7 has a desiccant-shaped through hole reserved therein, and the thickness is 2 mm. Figure 8 As shown, the desiccant printing template 7 is placed on the surface of the inorganic glass 4, a sufficient amount of desiccant is dotted, and the desiccant is printed from the through holes of the desiccant printing template 7 onto the surface of the inorganic glass 5 using a precision scraper.

[0052] After step S4, the organic adhesive module 31, the ultraviolet light absorber module 32, and the desiccant module 33 printed on the surface of the inorganic glass 4 from outside to inside form the adhesive layer 3, which are connected side by side and have the same height. The width ratio of the organic adhesive module 31 is 1 / 2, the width ratio of the ultraviolet light absorber module 32 is 1 / 4, and the width ratio of the desiccant module 33 is 1 / 4.

[0053] S5. Connecting. The inorganic glass 4 obtained in step S4 is placed upside down on the top surface of the LED bracket 1 , wherein the lower surface of the adhesive layer 3 is connected to the top surface of the LED bracket 1 , and the four sides of the inorganic glass 4 are aligned with the four sides of the LED bracket 1 .

[0054] S6. Heat and cure, using constant temperature heating at 120°C for 1 hour to complete the packaging process.

[0055] After the above steps S1-S6, a UV LED packaging structure according to the present invention is obtained, such as Fig. 9 shown.

[0056] Example 2

[0057] The preparation steps are generally the same as those in Example 1, except that:

[0058] In step S1, the UV LED chip is preferably a vertical chip with a size of 20 x 20 mil, a light emitting wavelength of 365 nm, and a height of 120 μm;

[0059] In step S2, the LED bracket 1 is provided with a through-hole metal circuit, the positive electrode of which is located directly below the ultraviolet LED chip 2, and the gold wire only connects the negative electrode of the ultraviolet LED chip 2 with the negative electrode part of the through-hole metal circuit.

[0060] In step S3, the ultraviolet absorber module 32 is formed by mixing PDMS and ultraviolet absorbing particles in a certain mass ratio, and the ultraviolet absorbing particles are preferably titanium dioxide (TiO2) with a mass concentration of 15wt%; the desiccant module 33 is formed by mixing PDMS and dry particles in a certain ratio, and the dry particles are preferably calcium oxide (CaO) with a mass concentration of 8wt%,

[0061] In step S4, the adhesive layer is printed. The organic adhesive module 31, the desiccant module 33, and the ultraviolet absorber module 32 are printed and placed on the surface of the inorganic glass 4 by using a template printing method to form an adhesive layer 3. The shape of the inorganic glass 4 is consistent with the bottom shape of the LED bracket 1, both are rectangular, with a size of 5.0 x 5.0 mm and a height of 1.5 mm.

[0062] S41. The organic adhesive printing template is pre-set with an organic adhesive-shaped through hole, and has a thickness of 2 mm. The organic adhesive printing template 5 is placed on the surface of the inorganic glass 4, and a sufficient amount of organic adhesive is applied, and the organic adhesive is printed from the through hole of the organic adhesive printing template 5 onto the surface of the inorganic glass 4 using a precision scraper.

[0063] S42. The desiccant printing template 7 is provided with a through hole in the shape of a desiccant and has a thickness of 2 mm. The desiccant printing template 7 is placed on the surface of the inorganic glass 4, and a sufficient amount of desiccant is applied, and the desiccant is printed from the through hole of the desiccant printing template 7 onto the surface of the inorganic glass 5 using a precision scraper.

[0064] S43. The UV absorber printing template 6 is pre-set with a UV absorber-shaped through hole, and the thickness is 2 mm. The UV absorber printing template 6 is placed on the surface of the inorganic glass 4, and a sufficient amount of UV absorber is applied, and the UV absorber is printed from the through hole of the UV absorber printing template 6 onto the surface of the inorganic glass 4 using a precision scraper.

[0065] After step S4, the organic adhesive module 31, the desiccant module 33, and the ultraviolet absorber module 32 printed on the surface of the inorganic glass 4 from left to right together form an adhesive layer 3, which are connected side by side and have the same height. The width of the organic adhesive module accounts for 1 / 2 of the adhesive layer, the width of the desiccant module accounts for 1 / 4 of the adhesive layer, and the width of the ultraviolet absorber module accounts for 1 / 4 of the adhesive layer.

[0066] After the above steps S1-S6, a UV LED packaging structure according to the present invention is obtained, such as Fig.10 shown.

[0067] Example 3

[0068] The preparation steps are generally the same as those in Example 1, except that:

[0069] In step S1, the ultraviolet LED chip is preferably a flip chip with a size of 50 x 50 mil, a light emitting wavelength of 395 nm, and a height of 180 μm.

[0070] In step S2 , the LED bracket 1 is provided with a through-hole metal circuit, and the positive electrode and the negative electrode of the through-hole metal circuit are directly connected to the bottom of both sides of the ultraviolet LED chip 2 respectively.

[0071] After step S4, the organic adhesive module 31, the ultraviolet light absorber module 32, and the desiccant module 33 printed on the surface of the inorganic glass 4 from left to right together form an adhesive layer 3, which are connected side by side and have the same height. The width of the organic adhesive module accounts for 1 / 3 of the adhesive layer, the width of the desiccant module accounts for 1 / 3 of the adhesive layer, and the width of the ultraviolet light absorber module accounts for 1 / 3 of the adhesive layer.

[0072] After the above steps S1-S6, a UV LED packaging structure according to the present invention is obtained, such as Fig.11 shown.

[0073] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A UV LED packaging structure, characterized in that: include: LED bracket, ultraviolet LED chip, adhesive layer and inorganic glass; the LED bracket is placed on the bottom layer; The ultraviolet LED chip is placed on the upper surface of the inner cavity of the LED bracket, and the ultraviolet LED chip is connected to the through-hole metal circuit in the inner cavity of the LED bracket; the adhesive layer is located on the top surface of the LED bracket, and connects the LED bracket to the inorganic glass to achieve sealing; The inorganic glass is located on the top of the UV LED, and the lower surface of the inorganic glass is in contact with the upper surface of the bonding layer; The width of the adhesive layer is consistent with the width of the edge of the top surface of the LED bracket, and includes: an organic adhesive module, an ultraviolet light absorber module and a desiccant module. The organic adhesive module connects the LED bracket to the inorganic glass. The ultraviolet light absorber module is used to block the ultraviolet light emitted by the ultraviolet LED chip from affecting the aging and degradation of the organic adhesive. The desiccant module is used to block the water vapor component of the external air environment to protect the ultraviolet LED chip from being affected by it. The organic adhesive module, the ultraviolet light absorber module and the desiccant module are connected side by side with the same height, and the organic adhesive module is placed in the outermost layer; The organic adhesive module includes one or a combination of two or more materials such as silica gel and polydimethylsiloxane; the ultraviolet absorber module is composed of polydimethylsiloxane and ultraviolet absorbing particles mixed in a certain mass ratio; and the desiccant module is composed of polydimethylsiloxane and dry particles mixed in a certain ratio.

2. The LED packaging structure according to claim 1, characterized in that: From outside to inside, it includes two combinations of organic adhesive module / ultraviolet absorber module / desiccant module and organic adhesive module / desiccant module / ultraviolet absorber module, wherein: the width of the organic adhesive module accounts for 1 / 3-2 / 3 of the adhesive layer, the width of the ultraviolet absorber module accounts for 1 / 6-1 / 3 of the adhesive layer, and the width of the desiccant module accounts for 1 / 6-1 / 3 of the adhesive layer.

3. The LED packaging structure according to claim 1, characterized in that: The ultraviolet absorbing particles include one or a combination of two or more of zinc oxide, titanium dioxide, and iron oxide, with a mass concentration of 5-25 wt%; the dry particles include one or a combination of calcium oxide, anhydrous calcium chloride, aluminum oxide, calcium sulfate, and sodium sulfate, with a mass concentration of 5-25 wt%.

4. The LED packaging structure according to claim 1, characterized in that: The LED bracket is provided with an inner cavity through-hole metal circuit, which is divided into positive and negative poles. The positive pole of the through-hole metal circuit is connected to the positive pole of the ultraviolet LED chip, and the negative pole of the through-hole metal circuit is connected to the negative pole of the ultraviolet LED chip; a metal reflective layer is provided on the inner cavity surface of the LED bracket.

5. The LED packaging structure according to claim 1, characterized in that: The UV LED chip is rectangular in shape, with a light emission wavelength of 250-410 nm and a height of 50-200 μm.

6. The LED packaging structure according to claim 1, characterized in that: The shape of the inorganic glass is consistent with the bottom shape of the LED bracket, and the height is 0.5-3 mm.

7. A method for preparing an ultraviolet LED packaging structure, characterized in that: The organic adhesive module, the ultraviolet light absorber module and the desiccant module are connected side by side with the same height, and the organic adhesive module is placed on the outermost layer; the steps include: S1. Bonding: Use a bonding machine to fix the UV LED chip at the center of the upper surface of the LED bracket cavity; S2. Electrical connection: connect the UV LED chip to the metal circuit inside the LED bracket; S3. Preparing an organic binder, a UV absorber, and a desiccant, wherein the UV absorber is formed by mixing PDMS and UV absorbing particles in a certain mass ratio and subjected to vacuum degassing; the desiccant is formed by mixing PDMS and dry particles in a certain ratio and subjected to vacuum degassing; S4. Printing an adhesive layer: using a template printing method, printing an organic adhesive, an ultraviolet light absorber, and a desiccant on the surface of the inorganic glass to form an organic adhesive module, an ultraviolet light absorber module, and a desiccant module, which together constitute an adhesive layer; S5 connection: the inorganic glass obtained in step S4 is placed upside down on the top surface of the LED bracket, wherein the lower surface of the adhesive layer is connected to the top surface of the LED bracket, and the four sides of the inorganic glass are aligned with the four sides of the LED bracket; S6. Heat and cure to complete the packaging process.

8. The preparation method according to claim 7, characterized in that: In step S4, the organic adhesive is printed on the surface of the inorganic glass through an organic adhesive printing template, the ultraviolet absorber is printed on the surface of the inorganic glass through an ultraviolet absorber printing template, and the desiccant is printed on the surface of the inorganic glass through a desiccant printing template; wherein: the organic adhesive printing template is reserved with an organic adhesive module-shaped through hole, the ultraviolet absorber printing template is reserved with an ultraviolet absorber module-shaped through hole, and the desiccant printing template is reserved with a desiccant module-shaped through hole.

9. The preparation method according to claim 7, characterized in that: In step S6, the heating curing temperature is 80-180° C. and the time is 1-3 h.

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