Light source with high color rendering index and preparation method thereof

Abstract

The invention discloses a light source with a high color rendering index and a preparation method of the light source, and belongs to the field of semiconductors, the light source with the high color rendering index comprises a substrate, an LED assembly and fluorescent glue, the fluorescent glue comprises primer and composite fluorescent powder, and the mass ratio of the composite fluorescent powder to the primer is (0.2-0.4): 1; the primer comprises the following components in parts by weight: 85-86 parts of silica gel, 0.5-0.6 part of a silica gel curing agent, 8-10 parts of a thickness compensating agent, 0.5-1 part of a dispersing agent and other auxiliaries; the thickness compensating agent is TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres wrapped by PDMS (Polydimethylsiloxane). The PDMS-coated TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres are added, so that the influence caused by the thickness difference of the fluorescent glue layer is compensated, the sensitivity of the fluorescent glue layer to the thickness change of the fluorescent glue layer is reduced, the color development (color difference) influence caused by the thickness is weakened, and the allowable thickness difference can be expanded from the existing + / -0.02 mm to + / -0.05 mm or above.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductors and relates to a light source with a high color rendering index and a preparation method thereof. Background Art

[0002] High color rendering index LED light sources have important application value in the field of high-end lighting. However, during the production process of LED light sources, it is difficult to control the color consistency of products in the same batch, resulting in multiple color rendering effects in the same batch of products. This not only increases the difficulty of color selection in the later stage, but also increases the defective rate compared to the target color rendering product. The factors causing the above problems include the following:

[0003] 1. During the dispensing process, fluctuations in the dispensing machine parameters or changes in the fluidity of the curing agent in the fluorescent glue can lead to differences in the thickness of the fluorescent glue layer on the same batch of products. The thickness of some products exceeds the preset standard thickness range (the glue layer thickness error is within 0.02mm). When the thickness difference exceeds the above range, the color will show obvious color difference.

[0004] 2. Fluorescent glue settles during use;

[0005] The existing technology has a good solution to the sedimentation of fluorescent glue, but lacks a solution to compensate for thickness differences. Therefore, the defective rate of the color rendering link in the current LED light source production process is difficult to control and unstable. Summary of the Invention

[0006] The purpose of the present invention is to provide a light source with a high color rendering index and a preparation method thereof, which solves the problem that the existing technology for compensating thickness differences in the production process of LED light sources is lacking, resulting in high sensitivity to the thickness of the fluorescent glue layer in the production process of LED light sources. Different thicknesses will seriously affect the color difference, making the defective rate in the color rendering link difficult to control and unstable.

[0007] The technical solution adopted in the present invention is as follows:

[0008] A light source with a high color rendering index includes a substrate, an LED component, and a fluorescent glue. The fluorescent glue includes the following components: a primer and a composite fluorescent powder. The mass ratio of the composite fluorescent powder to the primer is 0.2-0.4:1.

[0009] The primer includes the following components in parts by weight: 85-86 parts of silica gel, 0.5-0.6 parts of silica gel curing agent, 8-10 parts of thickness compensating agent, 0.5-1 parts of dispersing agent, and other additives; the thickness compensating agent is TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres wrapped in PDMS.

[0010] Existing technologies are highly sensitive to thickness, and generally, the thickness difference of the fluorescent adhesive layer is within ±0.02mm, which does not cause obvious color differences. However, due to the long-term use of the dispensing machine, its parameters will fluctuate, and the curing agent will continue to contact with the silicone. During the dispensing process, the fluidity of the base glue will change, resulting in thickness differences between the products dispensed before and after. These factors make it difficult to maintain the thickness of the fluorescent adhesive layer within ±0.02mm for the same batch of products in the actual production process. If the thickness difference exceeds ±0.02mm, different color rendering effects will appear.

[0011] In view of the above problems, this application achieves thickness compensation by adding a thickness compensator to reduce thickness sensitivity and expand the allowable thickness difference to compensate for the color difference caused by thickness. The color difference caused by excessive thickness or thinness is reflected in the following aspects:

[0012] In the prior art, when the thickness is too thick, the shrinkage internal stress during the curing process increases, and the internal temperature gradient is high. This increased internal stress causes cracks or delamination in the phosphor layer. Structural defects affect the scattering and transmission of light, resulting in uneven light output in local areas, causing uneven color space distribution ("yellow ring" effect), which in turn affects the color rendering effect. In addition, if the thickness of the adhesive layer is too thick, the actual optical path will be increased. The greater the optical path difference, the more obvious the color difference.

[0013] In the prior art, when the thickness is too thin, although the internal stress is reduced, the blue light has strong penetration, the phosphor is not sufficiently excited, the proportion of blue light in the white light is too high, and the color temperature is too high (too cold);

[0014] The compensation principle of the PDMS-wrapped TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres in this application is as follows:

[0015] 1. Polydimethylsiloxane (PDMS) has high elasticity and low modulus, which can partially buffer the shrinkage internal stress caused by thickness differences during the curing process. When the fluorescent adhesive layer is too thick, the PDMS microspheres disperse the local stress through deformation, inhibiting the formation of cracks or delamination, thereby maintaining structural integrity and avoiding uneven light scattering (such as the "yellow ring" effect) caused by structural defects.

[0016] 2. TiO2 and ZrO2 have high refractive indices, which can enhance the scattering of blue light in the fluorescent glue layer, providing a sufficient excitation path for the phosphor in the glue layer. This can be understood as follows: in the actual production process, at standard thickness, the excitation path of the phosphor provided in this application is extended while ensuring that the color rendering effect meets the target setting. Because the standard color temperature of semiconductor color rendering is generally a range of values, rather than a fixed value, after adding PDMS-wrapped TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres in this application, at this ratio, although the excitation path is increased, that is, the optical path is increased, the degree of increase is within the color temperature standard range set for the color rendering. Then, when the glue layer decreases relative to the target thickness, the degree of decrease is compensated by the extended excitation path of the microspheres, compensating for the high color temperature problem caused by insufficient thickness, making the color rendering more consistent, and expanding the lower limit thickness difference that can occur in the fluorescent glue layer compared to the prior art.

[0017] 3. Mesoporous SiO2 microspheres have highly ordered nanopores (pore diameter of about 10-20nm) and high specific surface area (>500m 2 / g) and surface hydroxyl groups (-OH) provide uniform loading space for liquid crystal molecules. The mesoporous microspheres were immersed in an ethanol solution of nematic liquid crystal E7. Under vacuum (-0.1MPa) and elevated temperature (40°C), the liquid crystal molecules were drawn into the pores by capillary force. After cooling to room temperature (25°C), the liquid crystals were orderly arranged along the axial direction of the pores within the mesopore confinement. When the shrinkage stress of the adhesive layer increased significantly, the stress not buffered by the polydimethylsiloxane exerted a compressive force on the mesoporous microspheres. At this point, the liquid crystal molecules partially or completely switched from parallel pore arrangement to vertical arrangement, resulting in a decrease in the equivalent refractive index, reducing the optical path difference caused by the increase in thickness and minimizing chromatic aberration.

[0018] In this application, the dispersant ensures the uniform dispersion of the microspheres and phosphor in the silica gel, the silica gel curing agent is used to promote the curing of the silica gel, and other additives such as stabilizers are used to assist in adjusting the overall performance of the fluorescent glue and are used selectively according to actual conditions.

[0019] In the present application, the TiO2 / ZrO2 gradient refractive index shell requires mesoporous silica microspheres as core materials to provide support for it; liquid crystal also requires mesoporous silica microspheres as carriers; equivalently, in the present application, the mesoporous silica microspheres serve as bridges to structurally form an integral structure of the TiO2 / ZrO2 gradient refractive index shell and liquid crystal, thereby avoiding the problem of component sedimentation and poor compatibility between different components caused by the use of multiple component materials alone; in addition, the present application forms a smooth refractive index transition from a mesoporous SiO2 core loaded with liquid crystal → a TiO2 / ZrO2 gradient refractive index shell → a silica gel matrix, and the gradient refractive index causes light to be gradually deflected on the surface of the microspheres rather than abruptly reflected, thereby improving light transmission efficiency.

[0020] Furthermore, the PDMS-wrapped TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres are prepared by the following method:

[0021] A1. Vacuum impregnation: The mesoporous SiO2 microspheres were placed in a vacuum drying oven and evacuated to -0.1 MPa. The microspheres were then immersed in an ethanol solution of nematic liquid crystal E7. The temperature was raised to 40°C, maintained for 2 hours, filtered, cooled to room temperature, and cooled to solidify to obtain a first intermediate, wherein the mass of the nematic liquid crystal E7 was 30-35% of the mass of the mesoporous SiO2 microspheres.

[0022] B1. Construction of a TiO2 / ZrO2 graded refractive index shell: Using atomic layer deposition technology, a TiO2 layer, a TiO2-ZrO2 mixed layer, and a ZrO2 layer are sequentially formed on the surface of the cleaned first intermediate from the inside out to obtain a second intermediate;

[0023] After surface treatment of the second intermediate with C1 and a silane coupling agent, the second intermediate was dispersed in a PDMS prepolymer containing a crosslinking agent, ultrasonically treated for 30 minutes, and cured after vacuum degassing to obtain PDMS-wrapped TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres.

[0024] Furthermore, the thickness of the TiO2 layer is 50 nm, the thickness of the TiO2-ZrO2 mixed layer is 26 nm, and the thickness of the ZrO2 layer is 20 nm.

[0025] Furthermore, the thickness of the TiO2-ZrO2 mixed layer is 26 nm, and the deposition conditions of the TiO2-ZrO2 mixed layer are: single-cycle deposition of 0.2 nm, 1-52 cycle sections, the circulation ratio of precursor TiCl4:ZrCl4 is 3:1; 53-78 cycle sections, the circulation ratio of precursor TiCl4:ZrCl4 is 1:1; 79-130 cycle sections, the circulation ratio of precursor TiCl4:ZrCl4 is 1:3.

[0026] Furthermore, the composite phosphor includes at least red phosphor and green phosphor, and the LED component includes a blue light chip; and the color rendering index of the fluorescent glue is greater than or equal to 95.

[0027] Furthermore, the composite phosphor includes green-yellow powder, red powder, and green powder, and the mass ratio of the green-yellow powder, red powder, and green powder is 6:3:1.

[0028] In combination with the above content, the present application compensates for the impact of the thickness difference of the fluorescent glue layer by adding PDMS-wrapped TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres, reduces the sensitivity of the fluorescent glue layer to its thickness changes, and weakens the color rendering (color difference) effect caused by the thickness. The allowable thickness difference can be expanded from the existing ±0.02mm to more than ±0.05mm. The thickness change within the error of about ±0.05mm will not cause obvious color rendering difference, and the color temperature is within the set standard color rendering range.

[0029] Furthermore, the silicone curing agent is a capsule-type platinum catalyst, the core material of the capsule-type platinum catalyst is a platinum-divinyltetramethyldisiloxane complex, the wall material of the capsule-type platinum catalyst is a polycaprolactone-zinc stearate complex, and the outside of the capsule-type platinum catalyst wall material is wrapped with a hydroxyl-terminated polydimethylsiloxane modification layer.

[0030] In the prior art, in order to prevent the platinum catalyst from promoting the curing of silicone before curing and affecting the fluidity of silicone, an inhibitor of the platinum catalyst is generally added. The addition of some inhibitors will directly affect the color of the fluorescent adhesive layer and the color development of the fluorescent adhesive layer; therefore, the present application adopts a capsule-type platinum catalyst, and blocks the contact between the platinum catalyst and the silicone by the wall material to avoid premature curing; the wall material is a polycaprolactone-zinc stearate composite, which will melt at the curing temperature, causing the capsule shell to rupture and release the catalyst inside.

[0031] Furthermore, the silica gel is phenyl methyl silica gel, and the dispersant is a hyperbranched dispersant.

[0032] Furthermore, the other auxiliary agents include 1-2 parts of polyurethane-modified cellulose nanocrystals and 0.5-1 part of hindered phenol / phosphite complex.

[0033] The method for preparing a light source with a high color rendering index comprises the following steps:

[0034] S1. Prepare fluorescent glue: Evenly mix silica gel, silica gel curing agent, thickness compensating agent, dispersant, and other additives in the dispersant to obtain a base glue, then mix the composite phosphor with the base glue in proportion, stir evenly, and vacuum degas to obtain the fluorescent glue;

[0035] S2. Glue dispensing: Use a glue dispensing machine to evenly apply the fluorescent glue on the light-emitting surface of the LED component of the substrate;

[0036] S3. Curing: After dispensing, perform step curing, first curing at 60°C for 10-15 minutes, then curing at 120°C for 1-1.5 hours to obtain an LED light source.

[0037] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0038] 1. A light source with a high color rendering index compensates for the impact of thickness variations in the fluorescent adhesive layer by adding PDMS-coated TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres, reducing the sensitivity of the fluorescent adhesive layer to thickness variations and weakening the color rendering (color difference) effect caused by thickness. The permissible thickness difference can be expanded from the current ±0.03mm to over ±0.05mm.

[0039] 2. The curing agent in the present invention is a capsule-type curing agent, which realizes delayed curing and avoids the fluorescent glue from curing prematurely and causing obvious changes in fluidity during the dispensing process. The smaller the fluidity change, the further the thickness difference of the fluorescent glue layer will be reduced, which helps to reduce the defective rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort, among which:

[0041] Figure 1 This is a picture of the actual product of the present invention;

[0042] Figure 2 This is a microscopic image of the PDMS-wrapped TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres of the present invention. DETAILED DESCRIPTION

[0043] In order to make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present invention and are not intended to limit the present invention. That is, the embodiments described herein are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and illustrated in the drawings herein may be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but is merely intended to represent selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0045] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0046] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0047] Example 1

[0048] A preferred embodiment of the present invention provides a light source with a high color rendering index, comprising a substrate, an LED component, and a fluorescent glue, wherein the fluorescent glue comprises the following components: a primer, a composite fluorescent powder, and a mass ratio of the composite fluorescent powder to the primer of 0.2:1;

[0049] The primer comprises the following components in parts by weight: 85-86 parts of phenyl methyl silicone, 0.5-0.6 parts of silicone curing agent, 8-10 parts of thickness compensator, 0.5-1 parts of dispersant, 1-2 parts of polyurethane modified cellulose nanocrystals, and 0.5-1 parts of hindered phenol / phosphite complex; the thickness compensator is PDMS-wrapped TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres.

[0050] The PDMS-wrapped TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres were prepared by the following method:

[0051] A1. Vacuum impregnation: The mesoporous SiO2 microspheres were placed in a vacuum drying oven and evacuated to -0.1 MPa. The microspheres were then immersed in an ethanol solution of nematic liquid crystal E7. The temperature was raised to 40°C, maintained for 2 hours, filtered, cooled to room temperature, and cooled to solidify to obtain a first intermediate, wherein the mass of the nematic liquid crystal E7 was 30-35% of the mass of the mesoporous SiO2 microspheres.

[0052] B1. Construction of a TiO2 / ZrO2 graded refractive index shell: Using atomic layer deposition technology, a TiO2 layer, a TiO2-ZrO2 mixed layer, and a ZrO2 layer are sequentially formed on the surface of the cleaned first intermediate from the inside out to obtain a second intermediate;

[0053] After surface treatment of the second intermediate with C1 and a silane coupling agent, the second intermediate was dispersed in a PDMS prepolymer containing a crosslinking agent, ultrasonically treated for 30 minutes, and cured after vacuum degassing to obtain PDMS-wrapped TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres. The microscopic image of the PDMS-wrapped TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres prepared within the scope of the above method of the present application is shown in FIG. Figure 2 shown.

[0054] The thickness of the TiO2 layer is 50 nm, the thickness of the TiO2-ZrO2 mixed layer is 26 nm, and the thickness of the ZrO2 layer is 20 nm.

[0055] The thickness of the TiO2-ZrO2 mixed layer is 26nm, and the deposition conditions of the TiO2-ZrO2 mixed layer are: single cycle deposition 0.2nm, 1-52 cycle section, the circulation ratio of precursor TiCl4:ZrCl4 is 3:1; 53-78 cycle section, the circulation ratio of precursor TiCl4:ZrCl4 is 1:1; 79-130 cycle section, the circulation ratio of precursor TiCl4:ZrCl4 is 1:3.

[0056] The composite phosphor includes green-yellow powder, red powder, and green powder, and the mass ratio of green-yellow powder, red powder, and green powder is 6:3:1. The LED component includes a blue light chip;

[0057] The silicone curing agent is a capsule-type platinum catalyst, the core material of which is a platinum-divinyltetramethyldisiloxane complex, and the wall material of which is a polycaprolactone-zinc stearate complex. The exterior of the capsule-type platinum catalyst wall material is coated with a hydroxyl-terminated polydimethylsiloxane modification layer. The amount of polycaprolactone-zinc stearate complex and hydroxyl-terminated polydimethylsiloxane added is not particularly limited and can be adjusted according to actual conditions with reference to existing technologies.

[0058] The dispersant is a hyperbranched dispersant.

[0059] The method for preparing a light source with a high color rendering index comprises the following steps:

[0060] S1. Prepare fluorescent glue: Evenly mix silica gel, silica gel curing agent, thickness compensating agent, dispersant, and other additives in the dispersant to obtain a base glue, then mix the composite phosphor with the base glue in proportion, stir evenly, and vacuum degas to obtain the fluorescent glue;

[0061] S2. Glue dispensing: Use a glue dispensing machine to evenly apply the fluorescent glue on the light-emitting surface of the LED component of the substrate;

[0062] S3. Curing: After dispensing, perform step curing, first curing at 60°C for 10-15 minutes, then curing at 120°C for 1-1.5 hours to obtain an LED light source.

[0063] Example 2

[0064] This embodiment is based on Example 1, but differs from Example 1 in that the mass ratio of the composite phosphor to the primer is 0.3:1, and the rest are the same. Figure 1 This is an actual product diagram within the scope of this embodiment, such as Figure 1 As shown, the fluorescent glue is uniform in color and has no obvious particles.

[0065] Example 3

[0066] This embodiment is based on Example 1, but differs from Example 1 in that the mass ratio of the composite phosphor to the primer is 0.4:1, and the rest are the same.

[0067] Comparative Example 1

[0068] This comparative example is based on Example 2, and the difference from Example 2 is that the primer does not include a thickness compensator, and the rest are the same. This comparative example provides a light source with a high color rendering index, including a substrate, an LED component and a fluorescent glue, and the fluorescent glue includes the following components: a primer, a composite phosphor, and the mass ratio of the composite phosphor to the primer is 0.3:1; the primer includes the following components in parts by weight: 85-86 parts of phenyl methyl silicone, 0.5-0.6 parts of silicone curing agent, 0.5-1 parts of dispersant, 1-2 parts of polyurethane modified cellulose nanocrystals, and 0.5-1 parts of hindered phenol / phosphite complex.

[0069] Comparative Example 2

[0070] This comparative example is based on Example 2. Unlike Example 2, this comparative example provides a light source with a high color rendering index, including a substrate, an LED component, and a fluorescent glue. The fluorescent glue includes the following components: a primer and a composite phosphor. The mass ratio of the composite phosphor to the primer is 0.3:1.

[0071] The primer includes the following components in parts by weight: 85-86 parts of phenyl methyl silicone, 0.5-0.6 parts of silicone curing agent, 11-12 parts of thickness compensator, 0.5-1 parts of dispersant, 1-2 parts of polyurethane modified cellulose nanocrystals, and 0.5-1 parts of hindered phenol / phosphite complex; the thickness compensator is PDMS-wrapped TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres, and the rest of the components are the same.

[0072] Comparative Example 3

[0073] This comparative example is based on Example 2. Unlike Example 2, this comparative example provides a light source with a high color rendering index, including a substrate, an LED component, and a fluorescent glue. The fluorescent glue includes the following components: a primer and a composite phosphor. The mass ratio of the composite phosphor to the primer is 0.3:1.

[0074] The primer includes the following components in parts by weight: 85-86 parts of phenyl methyl silicone, 0.5-0.6 parts of silicone curing agent, 6-7 parts of thickness compensator, 0.5-1 parts of dispersant, 1-2 parts of polyurethane modified cellulose nanocrystals, and 0.5-1 parts of hindered phenol / phosphite complex; the thickness compensator is PDMS-wrapped TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres, and the rest of the components are the same.

[0075] Comparative Example 4

[0076] This comparative example is based on Example 2. The difference from Example 2 is that the PDMS-wrapped TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres described in this comparative example are prepared by the following method:

[0077] A1. Vacuum impregnation: The mesoporous SiO2 microspheres were placed in a vacuum drying oven and evacuated to -0.1 MPa. The microspheres were then immersed in an ethanol solution of nematic liquid crystal E7. The temperature was raised to 40°C, maintained for 2 hours, filtered, cooled to room temperature, and cooled to solidify to obtain a first intermediate, wherein the mass of the nematic liquid crystal E7 was 30-35% of the mass of the mesoporous SiO2 microspheres.

[0078] B1. Construction of a TiO2 / ZrO2 graded refractive index shell: Using atomic layer deposition technology, TiO2 layers and ZrO2 layers are sequentially formed on the surface of the cleaned first intermediate from the inside out to obtain a second intermediate;

[0079] After surface treatment of the second intermediate with C1 and a silane coupling agent, the second intermediate was dispersed in a PDMS prepolymer containing a crosslinking agent, ultrasonically treated for 30 minutes, and cured after vacuum degassing to obtain PDMS-wrapped TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres.

[0080] The thickness of the TiO2 layer is 50 nm, and the thickness of the ZrO2 layer is 20 nm. The difference from Example 2 is that the TiO2 / ZrO2 graded refractive index shell does not include a TiO2-ZrO2 mixed layer, and the rest are the same.

[0081] Comparative Example 5

[0082] This comparative example is based on Example 2. The difference from Example 2 is that the mesoporous SiO2 microspheres in the thickness compensation agent of this comparative example do not carry liquid crystals, and the rest are the same.

[0083] Comparative Example 6

[0084] This comparative example is based on Example 2. The difference from Example 2 is that the thickness compensator of this comparative example does not include the TiO2 / ZrO2 graded refractive index shell, and the rest of the components are the same.

[0085] Comparative Example 7

[0086] This comparative example is based on Example 2. The difference from Example 2 is that the thickness compensator of this comparative example does not include a PDMS layer, and the rest are the same.

[0087] Comparative Example 8

[0088] This comparative example is based on Example 2. The difference from Example 2 is that the silicone curing agent in this comparative example is a platinum catalyst and does not have a capsule structure. The platinum catalyst is a platinum-divinyltetramethyldisiloxane complex and does not include a wall material and a hydroxyl-terminated polydimethylsiloxane modification layer. The rest of the parts are the same.

[0089] Comparative Example 9

[0090] This comparative example is based on Example 2. The difference from Example 2 is that the core material of the capsule-type platinum catalyst in this comparative example is a platinum-divinyltetramethyldisiloxane complex, the wall material of the capsule-type platinum catalyst is polycaprolactone, and the outside of the capsule-type platinum catalyst wall material is wrapped with a hydroxyl-terminated polydimethylsiloxane modification layer. The rest of the parts are the same.

[0091] Comparative Example 10

[0092] This comparative example is based on Example 2. The difference from Example 2 is that the core material of the capsule-type platinum catalyst in this comparative example is a platinum-divinyltetramethyldisiloxane complex, the wall material of the capsule-type platinum catalyst is a polycaprolactone-zinc stearate complex, and the outside of the capsule-type platinum catalyst wall material is not wrapped with a hydroxyl-terminated polydimethylsiloxane modification layer. The rest of the parts are the same.

[0093] Comparative Example 11

[0094] This comparative example is based on Example 2. The difference from Example 2 is that the mass of the nematic liquid crystal E7 in this comparative example is 36-38% of the mass of the mesoporous SiO2 microspheres, and the rest are the same.

[0095] Comparative Example 12

[0096] This comparative example is based on Example 2. The difference from Example 2 is that the mass of the nematic liquid crystal E7 in this comparative example is 28-29% of the mass of the mesoporous SiO2 microspheres, and the rest are the same.

[0097] Test Example 1

[0098] The color tolerance of the LED light sources prepared in Examples 1-3, Comparative Examples 1-7, and Comparative Examples 11-12 was tested, and the results are shown in Table 1.

[0099] The detection method is as follows: using the same batch of blue light LED chips (wavelength 450±5nm), fluorescent glue is coated on the substrate by a high-precision dispensing machine to prepare samples of different thicknesses. The target thickness is set to 200μm (standard light source), and the thickness differences of other samples are ±0.02mm, ±0.05mm, and ±0.07mm. According to the national standard (GB24823-2009), the color tolerance ΔE is calculated. The color tolerance ≤7 is qualified. The results are shown in Table 1.

[0100] Table 1 Color tolerance (ΔE) under different thickness differences

[0101]

[0102] As shown in Table 1, in accordance with the national standard (GB24823-2009), the thickness difference allowed for Examples 1-3 of the present invention after the addition of a thickness compensator is ±0.07 mm. Conventional dispensing machines or variations in the fluidity of fluorescent adhesive can cause thickness differences greater than ±0.02 mm, but generally less than ±0.07 mm. Therefore, the present invention reduces the impact of thickness on color development and color differences, thereby reducing the defective rate caused by thickness differences during product production. The color rendering index of the fluorescent adhesives within the range of Examples 1-3 of the present invention is ≥95.

[0103] Test Example 2

[0104] The viscosity change rate of the fluorescent glue prepared in Example 2 and Comparative Examples 8-10 at 25°C for 30 minutes, 60 minutes, 90 minutes and 240 minutes was tested. The viscosity change rate (%) = (ηt-η0) / η0×100%; ηt is the viscosity at time t (mPa·s), η0 is the initial viscosity (mPa·s), and the results are shown in Table 2.

[0105] Table 2 Viscosity change rate of fluorescent glue

[0106] 30 minutes 60 minutes 90 minutes 240 minutes Example 2 ＜2％ ＜5％ ＜10％ ＜18％ Comparative Example 8 ＞5％ ＞10％ ＞20％ ＞50％ Comparative Example 9 ＜2％ ＞5％ ＞15％ ＞50％ Comparative Example 10 ＜2％ ＞5％ ＞10％ ＞30％

[0107] Generally speaking, the greater the viscosity, the lower the fluidity. Platinum catalyst, as a silicone curing agent, can also promote the curing of silicone at room temperature. As the curing process progresses, the fluidity of silicone deteriorates, affecting the thickness of the fluorescent adhesive layer. The present invention uses a capsule layer to inhibit the corrosion of the platinum curing agent. Compared with the existing technology, the present invention can be used continuously for a longer time without significantly increasing the thickness of the fluorescent adhesive layer.

[0108] Test Example 3

[0109] The fluorescent adhesive layers with a thickness of 200 μm after curing prepared in Examples 1-3 and Comparative Examples 1-3 were visually observed to see if there was any delamination or cracking. The mechanical strength of the fluorescent adhesive layers prepared in Examples 1-3 and Comparative Examples 1-12 was measured. The results are shown in Table 3. The detection method was based on the prior art.

[0110] Table 3 Performance test of the fluorescent adhesive layer after curing

[0111]

[0112]

[0113] The fluorescent adhesive layer after curing of the present invention is as follows Figure 1 As shown, the adhesive layer has high stability, no delamination or cracking and has high mechanical strength.

[0114] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions and improvements made by any technician familiar with the field within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A light source with a high color rendering index, comprising a substrate, an LED component, and a fluorescent adhesive, characterized in that: The fluorescent glue comprises the following components: a base glue and a composite fluorescent powder, wherein the mass ratio of the composite fluorescent powder to the base glue is 0.2-0.4:1; The primer includes the following components in parts by weight: 85-86 parts of silica gel, 0.5-0.6 parts of silica gel curing agent, 8-10 parts of thickness compensating agent, 0.5-1 parts of dispersing agent, and other additives; the thickness compensating agent is TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres wrapped in PDMS.

2. The light source with a high color rendering index according to claim 1, characterized in that: The PDMS-wrapped TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres were prepared by the following method: A1. Vacuum impregnation: The mesoporous SiO2 microspheres were placed in a vacuum drying oven and evacuated to -0.1 MPa. The microspheres were then immersed in an ethanol solution of nematic liquid crystal E7. The temperature was raised to 40°C, maintained for 2 hours, filtered, cooled to room temperature, and cooled to solidify to obtain a first intermediate, wherein the mass of the nematic liquid crystal E7 was 30-35% of the mass of the mesoporous SiO2 microspheres. B1. Construction of a TiO2 / ZrO2 graded refractive index shell: Using atomic layer deposition technology, a TiO2 layer, a TiO2-ZrO2 mixed layer, and a ZrO2 layer are sequentially formed on the surface of the cleaned first intermediate from the inside out to obtain a second intermediate; After surface treatment of the second intermediate with C1 and a silane coupling agent, the second intermediate was dispersed in a PDMS prepolymer containing a crosslinking agent, ultrasonically treated for 30 minutes, and cured after vacuum degassing to obtain PDMS-wrapped TiO2 / ZrO2-SiO2 mesoporous-liquid crystal composite microspheres.

3. The light source with a high color rendering index according to claim 2, characterized in that: The thickness of the TiO2 layer is 50 nm, the thickness of the TiO2-ZrO2 mixed layer is 26 nm, and the thickness of the ZrO2 layer is 20 nm.

4. The light source with a high color rendering index according to claim 3, characterized in that: The thickness of the TiO2-ZrO2 mixed layer is 26nm, and the deposition conditions of the TiO2-ZrO2 mixed layer are: single cycle deposition 0.2nm, 1-52 cycle section, the circulation ratio of precursor TiCl4:ZrCl4 is 3:1; 53-78 cycle section, the circulation ratio of precursor TiCl4:ZrCl4 is 1:1; 79-130 cycle section, the circulation ratio of precursor TiCl4:ZrCl4 is 1:

3.

5. The light source with a high color rendering index according to claim 1, characterized in that: The composite phosphor includes at least red phosphor and green phosphor, and the LED component includes a blue light chip; the color rendering index of the fluorescent glue is greater than or equal to 95.

6. The light source with a high color rendering index according to claim 1, characterized in that: The composite phosphor powder includes green-yellow powder, red powder and green powder, and the mass ratio of the green-yellow powder, red powder and green powder is 6:3:

1.

7. The light source with a high color rendering index according to claim 1, characterized in that: The silicone curing agent is a capsule-type platinum catalyst, the core material of the capsule-type platinum catalyst is a platinum-divinyltetramethyldisiloxane complex, the wall material of the capsule-type platinum catalyst is a polycaprolactone-zinc stearate complex, and the outside of the capsule-type platinum catalyst wall material is wrapped with a hydroxyl-terminated polydimethylsiloxane modification layer.

8. The light source with a high color rendering index and the method for preparing the same according to claim 1, wherein: The silica gel is phenyl methyl silica gel, and the dispersant is a hyperbranched dispersant.

9. The light source with a high color rendering index according to claim 1, characterized in that: The other auxiliary agents include 1-2 parts of polyurethane modified cellulose nanocrystals and 0.5-1 part of hindered phenol / phosphite complex.

10. A method for preparing a light source with a high color rendering index according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Prepare fluorescent glue: Evenly mix silica gel, silica gel curing agent, thickness compensating agent, dispersant, and other additives in the dispersant to obtain a base glue, then mix the composite phosphor with the base glue in proportion, stir evenly, and vacuum degas to obtain the fluorescent glue; S2. Glue dispensing: Use a glue dispensing machine to evenly apply the fluorescent glue on the light-emitting surface of the LED component of the substrate; S3. Curing: After dispensing, perform step curing, first curing at 60°C for 10-15 minutes, then curing at 120°C for 1-1.5 hours to obtain an LED light source.

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