Fluorescent glass for high-R14 warm white light LED and preparation method of fluorescent glass

Abstract

The invention discloses fluorescent glass for a high-R14 warm white light LED and a preparation method of the fluorescent glass, and belongs to the technical field of fluorescent glass, commercial glass powder, orange fluorescent powder, green fluorescent powder, epoxy resin and a dispersing agent are evenly mixed to obtain a powder raw material, deionized water and zirconium oxide are added for ball milling, and fluorescent glass slurry is obtained; adding a curing agent, carrying out ball milling again, then carrying out vacuum defoaming treatment, pouring the prepared fluorescent glass slurry into a mold, and after the fluorescent glass slurry is shaped and dried, obtaining a fluorescent glass biscuit; the prepared fluorescent glass biscuit is put into a muffle furnace to be subjected to glue discharging, sintering and polishing treatment, then the fluorescent glass finished product for the high-R14 warm white light LED is obtained, the prepared fluorescent glass can obtain warm white light with the color temperature being about 3500 K under the irradiation of a blue light LED, the special color rendering index R14 of the obtained warm white light reaches 90 or above, and when road vegetation illumination is conducted, the color rendering index R14 of the obtained warm white light reaches 90 or above, and the color rendering index R14 of the obtained warm white light reaches 90 or above. The light source with high reduction degree has positive influence on human eye health.

Description

Technical Field

[0001] The invention belongs to the technical field of fluorescent glass, and in particular relates to fluorescent glass for high R14 warm white light LED and a preparation method thereof. Background Art

[0002] Light-emitting diodes (LEDs) are highly efficient, energy-efficient, and long-lived semiconductor light sources, characterized by high luminous efficiency, low energy consumption, a long service life, high safety, and favorable environmental performance. They offer a variety of luminous colors and can be manufactured into a variety of light-emitting devices tailored to specific application scenarios and needs. LED light sources are widely used in a variety of fields, including indoor lighting, advertising signs, and plant growth.

[0003] Among them, warm white LED light sources are mostly used for greenhouse lighting, horticultural lighting, and road vegetation lighting. Commonly used YAG:Ce 3+ The white light synthesis method of yellow phosphor and blue LED chip has the problem that the red light emission ratio is small, and the spectrum shows a "blue canyon" phenomenon, resulting in a high color temperature and a high blue light content, which is a cold white light. Therefore, in order to supplement the red light component and absorb more blue light, phosphors of corresponding colors can be added. However, the common CASN:Eu 2+ Red phosphors often need to be sintered in a nitrogen environment because Eu 2+ Easily oxidized to Eu 3+ , so Gd-doped 3+ GdYAG:Ce 3+ Phosphor to supplement the red light component. In addition, due to LuAG:Ce 3+ The morphology is a cubic polyhedron, which is inconsistent with the spherical particles of YAG-based phosphors. Therefore, the same-base YAGG:Ce doped with Ga can be used. 3+ Green phosphor is used instead. Another often overlooked aspect is the reproduction of leaf color. The special color rendering index, R14, represents the degree of reproduction of the green color of leaves. High R14 light sources are crucial for protecting the human eye by reproducing green on green paths and for promptly detecting abnormalities during plant growth. Therefore, the production of high R14 warm white LED light sources has become increasingly important.

[0004] Traditional fluorescent conversion materials typically consist of an organic fluorescent coating applied to a blue LED chip. However, due to the heat generated by the LED chip during operation, the organic coating can deteriorate and become ineffective over time. Therefore, it is necessary to develop a fluorescent conversion material that can withstand high temperatures. Among these high-temperature fluorescent conversion materials, fluorescent ceramics are expensive and complex to prepare, and fluorescent single crystals lack scattering centers. In contrast, fluorescent glass is relatively inexpensive to prepare and offers excellent thermal stability, making it a promising candidate for fluorescent conversion materials.

[0005] Currently, the commonly used methods for preparing fluorescent glass are dry pressing and sintering or melt sintering. However, the uniformity of samples prepared by this method is difficult to ensure, the cost of dry pressing molds is high, and the dimensional accuracy of melt sintered samples is low. Gel casting technology has significant advantages in preparing complex-shaped parts and improving the strength and performance uniformity of green bodies. Compared with dry pressing and sintering, it is more suitable for near-net-size molding of complex shapes; compared with melt sintering, it has lower energy consumption and higher molding accuracy. Therefore, gel casting technology has broad application prospects in the preparation of fluorescent glass.

[0006] Among gel-casting systems, the most commonly used are the AM and Isobam systems. The AM system has gradually faded from use due to the presence of neurotoxic reagents. While the Isobam system contains fewer harmful substances, the resulting green body samples are relatively weak, making subsequent processing difficult. Epoxy resin systems have been used in gel-casting ceramic molding, offering advantages such as environmental friendliness and the ability to produce high-strength green bodies. Therefore, the use of epoxy resin systems for the preparation of fluorescent glass is both reasonable and feasible.

[0007] Early research investigated warm white LED devices and phosphor conversion materials. For example, patent CN218032889U discloses a yellow-green mixed-light integrated floodlight. This uses a combination of yellow and green LEDs to produce warm white LED light, improving the illumination of vegetation. However, when using different types of LEDs, the light decay rates of different chips vary, resulting in significant color shift over time. Furthermore, the patent fails to disclose specific values ​​for the color rendering index, leaving the precise degree of green reproduction unverified.

[0008] Patents CN206332053U and CN207489869U disclose a warm white LED light source that uses a dispensing method to apply a YAG phosphor coating to the LED substrate and blue light chip. However, under long-term high-temperature operation, the thermal stability of organic materials is poor, and the product lifespan is worrying. In addition, the light source obtained by this packaging method contains a large amount of blue light, which is harmful to human eye health.

[0009] Patent CN108503216A discloses a method for preparing fluorescent glass and the fluorescent glass itself. The glass is produced using a melt-sintering process, resulting in a warm white light with a low color temperature. However, the high melt-sintering temperature can easily cause thermal quenching of the phosphor. Furthermore, the shape of the melt-formed sample is difficult to determine, requiring further processing, resulting in waste and increased raw material costs.

[0010] Patent CN114751630B discloses a method for producing fluorescent glass by gel-casting, adding various phosphors to produce white LEDs with a high color rendering index. However, the system used is the Isobam system, which produces fluorescent glass blanks with low strength, making subsequent processing difficult and the yield difficult to guarantee. Summary of the Invention

[0011] Technical issues solved:

[0012] This application addresses the shortcomings of the prior art, such as the heat generated by LED chips during operation, the deterioration and failure of the organic coating caused by long-term use, the high cost of dry pressing molds, and the low dimensional accuracy of melt-sintered samples. The application provides a fluorescent glass for warm white light LEDs with a high R14 and a preparation method thereof. Under the excitation of a blue light LED, white light with a CCT of approximately 3500K can be obtained, and the blue light component is significantly reduced. This warm white light has significant advantages for plant lighting. Warm white light is beneficial to plant photosynthesis, can improve the effect of photosynthesis, and thereby promote the growth rate of plants, reduce the blue light component, and protect human eye health. The special color rendering index R14 of the sample prepared in this application can reach above 90, which means that its degree of restoration of the green color of leaves is very high. The system used in the present invention is a green and non-toxic system and is environmentally friendly.

[0013] Technical solution:

[0014] To achieve the above objectives, this application is implemented through the following technical solutions:

[0015] A method for preparing fluorescent glass for high R14 warm white light LED, comprising the following steps:

[0016] Step 1: Mix 4-10 parts of orange phosphor, 4-10 parts of green phosphor, 20-32 parts of commercial glass powder, 0.8-1 part of dispersant, 1.6-2 parts of epoxy resin, 0.1-0.3 part of curing agent, 60-80 parts of zirconium oxide balls, and 10-13 parts of deionized water according to the mass ratio;

[0017] Step 2: Commercial glass powder, orange phosphor, green phosphor, epoxy resin and dispersant are mixed evenly to obtain powder raw materials. The powder raw materials are added to deionized water in three batches, and then zirconium oxide balls are added and ball milled for 6 to 8 hours to obtain fluorescent glass slurry;

[0018] Step 3: Add curing agent to the ball-milled fluorescent glass slurry and ball-mill again for 15 to 30 minutes to mix and react fully, and then perform vacuum degassing treatment to finally obtain a fluorescent glass slurry with high solid content and low viscosity;

[0019] Step 4: Pour the prepared fluorescent glass slurry into a mold, place the mold filled with the slurry in a constant temperature and humidity box for 1 to 2 days to set, and then place it in a dry place for dehydration and drying for 1 to 2 days to obtain the fluorescent glass blank;

[0020] Step 5: Place the prepared fluorescent glass blank into a muffle furnace for debinding and sintering, and then polish to obtain a finished fluorescent glass product for high R14 warm white light LED.

[0021] Furthermore, in the first step, the orange phosphor is GdYAG:Ce phosphor, the green phosphor is GaYAG:Ce phosphor, the commercial glass powder is commercial low-temperature glass powder, the dispersant is ammonium polyacrylate, and the curing agent is one or more of polyethyleneimine, polyetheramine, and cardanol-modified phenolic amine.

[0022] Furthermore, the powder in the second step is added to deionized water in three batches, with the powder raw materials added at a mass ratio of 4:2:1 at time intervals of 1 to 2 hours to avoid adding too much powder raw materials at a single time to cause agglomeration.

[0023] Furthermore, in the third step, the rotation speed of the vacuum defoaming machine is 1000-3000 r / min, and the time is 1-5 min.

[0024] Furthermore, in the fifth step, the humidity is maintained at above 80% for 1-2 days during shaping, and the temperature is maintained at 20° C. to 30° C. during drying for 1-2 days.

[0025] Furthermore, in the sixth step, the debinding process is to heat the temperature from room temperature to 600°C to 700°C at a heating rate of 1 to 8°C / min, and keep it at 600 to 700°C for 45 to 90 minutes; the sintering process is to heat the temperature from room temperature to 700 to 900°C at a rate of 6 to 10°C / min, keep it at that temperature for 15 to 30 minutes, and finally cool it with the furnace.

[0026] The present application also discloses fluorescent glass for high R14 warm white light LEDs prepared by any of the above preparation methods.

[0027] Principle explanation: Orange phosphor GdYAG:Ce is used 3+ With green phosphor YAGG:Ce 3+The coordinated use not only supplements the red light component, but also avoids the occurrence of the "blue light canyon" phenomenon; in the process of plant growth, it is crucial to detect abnormal conditions of plants in a timely manner, and the high R14 light source can accurately restore the green color of the plants, so that any abnormal conditions of the plants can be detected in time; gel injection molding, as a near-net-size molding technology, can prepare molds according to the target shape, thereby reducing the parts that require additional processing and reducing the preparation cost; by selecting low-melting-point glass powder, temperature quenching of the phosphor during the sintering process is avoided, and the yellowing and aging phenomenon caused by the use of organic matter as the encapsulation layer under long-term light conditions is also avoided.

[0028] Beneficial effects:

[0029] This application provides a fluorescent glass for high R14 warm white LED and a preparation method thereof, which has the following beneficial effects compared with the prior art:

[0030] 1. The present invention provides a method for preparing fluorescent glass for high R14 warm white LEDs, using low-temperature glass powder as the matrix glass to avoid thermal quenching of the fluorescent powder caused by excessively high sintering temperatures;

[0031] 2. The present invention provides a method for preparing fluorescent glass for high R14 warm white LED, using the same-base phosphor GdYAG:Ce 3+ With YAGG:Ce 3+ While supplementing the orange light component, it avoids the occurrence of the "blue light canyon" phenomenon;

[0032] 3. The present invention provides a method for preparing fluorescent glass for high R14 warm white LEDs. The prepared fluorescent glass can produce warm white light with a color temperature of approximately 3500K under the illumination of blue LEDs, with a low blue light component. This method promotes plant photosynthesis and growth while maximally protecting human eye health.

[0033] 4. This invention provides a method for preparing fluorescent glass for warm white LEDs with a high R14 value. The prepared fluorescent glass, when illuminated by a blue LED, produces warm white light with a special color rendering index (R14) exceeding 90. This means that the light source can reproduce the green color of leaves with a high degree of accuracy. Promptly detecting abnormal plant conditions is crucial during plant growth. A light source with a high R14 value can accurately reproduce the green color of plants, allowing any abnormalities to be detected promptly. Furthermore, when used for roadside vegetation lighting, this highly reproducible light source has a positive impact on human eye health.

[0034] 5. The present invention provides a method for preparing fluorescent glass for high R14 warm white LEDs. The fluorescent glass is prepared using gel casting technology. The advantage of gel casting technology in near-net-size molding enables the preparation of samples with complex shapes, avoiding partial waste of raw materials during processing.

[0035] 6. The present invention provides a method for preparing fluorescent glass for warm white LEDs with a high R14 rating. The raw materials required for preparing the slurry are environmentally friendly, avoiding environmental damage during large-scale production.

[0036] 7. The present invention provides a method for preparing fluorescent glass for high R14 warm white light LEDs. The prepared fluorescent glass has good thermal stability, which not only avoids the performance degradation of epoxy resin caused by long-term lighting conditions, but also enhances its heat dissipation performance and extends the life of the fluorescent glass. At the same time, it is low in cost and suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a photo of the finished product of the fluorescent glass for high R14 warm white LED with different phosphor concentrations in this application;

[0038] Figure 2 This is a photo of the application showing a high R14 warm white LED illuminating green leaves with fluorescent glass;

[0039] Figure 3 This is a performance parameter diagram of the fluorescent glass for high R14 warm white light LED in this application. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and should not be used to limit the scope of protection of the present invention.

[0041] The commercial low-temperature glass powder is aluminosilicate glass powder with a commercial melting point of 600°C, which was purchased from Hebei Jiegui Mine Co., Ltd.

[0042] Example 1

[0043] A method for preparing fluorescent glass for high R14 warm white light LED, comprising the following steps:

[0044] Step 1: Prepare 4g of orange phosphor (GdYAG:Ce), 4g of green phosphor (GaYAG:Ce), 32g of commercial glass powder with a melting point of 600°C, 0.8g of dispersant ammonium polyacrylate, 1.6g of epoxy resin, 60g of zirconium oxide balls, and 13g of deionized water according to the mass ratio. Also, prepare a custom mold measuring 20×20×10mm, using a silicone mold made of a softer material that is easily demolded.

[0045] Step 2: Commercial glass powder, orange phosphor, green phosphor, epoxy resin and dispersant are mixed evenly to obtain powder raw materials. The powder raw materials are added to deionized water in three batches at a mass ratio of 4:2:1 at intervals of 1 to 2 hours to avoid agglomeration of the powder raw materials by adding too much at a time. Zirconia balls are then added and ball milled for 6 hours to obtain fluorescent glass slurry.

[0046] Step 3: Add 0.1g of curing agent polyethyleneimine to the ball-milled fluorescent glass slurry and ball-mill again for 15-30 minutes to mix and react thoroughly, then perform vacuum defoaming treatment at 1000r / min for 3 minutes to finally obtain a fluorescent glass slurry with high solid content and low viscosity;

[0047] Step 4: Pour the prepared fluorescent glass slurry into a mold, place the mold with the slurry in a constant temperature and humidity box and keep the humidity at 80% for 1 day to set it. After it is set, place it in a dry place and keep the temperature at 20°C for 1 day to obtain the fluorescent glass blank.

[0048] Step 5: The resulting fluorescent glass blank is placed in a muffle furnace and heated from room temperature to 600°C at a rate of 6°C / min to remove binder. The temperature is then held at 600°C for 45 minutes. The sample is then sintered at a rate of 6°C / min to 750°C, held for 15 minutes, and finally cooled in the furnace. The resulting sample is polished to obtain a finished fluorescent glass product for high R14 warm white LEDs.

[0049] Example 2

[0050] A method for preparing fluorescent glass for high R14 warm white light LED, comprising the following steps:

[0051] Step 1: Prepare 6.7g of orange phosphor (GdYAG:Ce), 6.7g of green phosphor (GaYAG:Ce), 26.7g of commercial glass powder with a melting point of 600°C, 0.9g of dispersant ammonium polyacrylate, 1.8g of epoxy resin, 70g of zirconium oxide balls, and 12g of deionized water, all in the following proportions by mass. Also, prepare a custom 25×25×10mm mold made of a soft, easily demoldable silicone material.

[0052] Step 2: Commercial glass powder, orange phosphor, green phosphor, epoxy resin and dispersant were mixed evenly to obtain powder raw materials. The powder raw materials were added to deionized water in three batches at a mass ratio of 4:2:1 at intervals of 1 to 2 hours to avoid agglomeration of the powder raw materials by adding too much at a time. Zirconia balls were then added and milled for 7 hours to obtain fluorescent glass slurry.

[0053] Step 3: Add 0.2g of curing agent polyetheramine to the ball-milled fluorescent glass slurry and ball-mill again for 20min to mix and react thoroughly, then perform vacuum defoaming treatment at 2000r / min for 2min to finally obtain a fluorescent glass slurry with high solid content and low viscosity;

[0054] Step 4: Pour the prepared fluorescent glass slurry into a mold, place the mold with the slurry in a constant temperature and humidity box and keep the humidity at 85% for 1 day to set it. After it is set, place it in a dry place and keep the temperature at 25°C for 1 day to obtain the fluorescent glass blank.

[0055] Step 5: Place the resulting fluorescent glass blank in a muffle furnace and heat it from room temperature to 650°C at a rate of 7°C / min to remove binder. Hold the temperature at 650°C for 60 minutes. Sinter the blank at a rate of 8°C / min to 800°C, hold it for 20 minutes, and cool it in the furnace. The resulting sample is polished to produce a finished fluorescent glass product for high R14 warm white LEDs.

[0056] Example 3

[0057] A method for preparing fluorescent glass for high R14 warm white light LED, comprising the following steps:

[0058] Step 1: Prepare 10g of orange phosphor (GdYAG:Ce), 10g of green phosphor (GaYAG:Ce), 20g of commercial glass powder with a melting point of 600°C, 1g of dispersant ammonium polyacrylate, 2g of epoxy resin, 80g of zirconium oxide balls, and 10g of deionized water, all in the following proportions by mass. Also, prepare a custom 30×30×10mm mold made of a soft, easily demoldable silicone material.

[0059] Step 2: Commercial glass powder, orange phosphor, green phosphor, epoxy resin and dispersant are mixed evenly to obtain powder raw materials. The powder raw materials are added to deionized water in three batches at a mass ratio of 4:2:1 at intervals of 1 to 2 hours to avoid agglomeration of the powder raw materials by adding too much at a time. Zirconia balls are then added and milled for 8 hours to obtain fluorescent glass slurry.

[0060] Step 3: Add 0.3 g of the curing agent cardanol-modified phenolic amine to the ball-milled fluorescent glass slurry and ball-mill again for 30 minutes to mix and react thoroughly, and then perform vacuum defoaming treatment at 3000 r / min for 1 minute to finally obtain a fluorescent glass slurry with high solid content and low viscosity;

[0061] Step 4: Pour the prepared fluorescent glass slurry into the mold, place the mold with the slurry in a constant temperature and humidity box to maintain the humidity at 90% for 2 days to set it, and then place it in a dry place after it is set, keep the temperature at 30°C and dry it for 2 days to obtain the fluorescent glass blank;

[0062] Step 5: Place the resulting fluorescent glass blank in a muffle furnace and heat it from room temperature to 700°C at a rate of 8°C / min to remove binder. Hold it at 7000°C for 60 minutes. Sinter it at a rate of 10°C / min to 825°C, hold it for 30 minutes, and finally cool it in the furnace. The resulting sample is polished to produce a finished fluorescent glass product for high R14 warm white LEDs.

[0063] like Figure 3 All data shown in the figure was measured using a Yuanfang EVERFINE SPIC-30SE spectral colorimeter. The left image shows a color temperature of 3686K and an R14 value of 90.9. The emission spectrum also reveals strong emission bands in green and orange-red. The green emission peak results in a higher R14 value, enabling better green reproduction; the orange-red emission band enables more efficient chlorophyll photosynthesis. The right image shows the R1-R15 distribution, more clearly demonstrating an R14 value of 90.

[0064] The examples selected in the above materials are intended to facilitate understanding and are not intended to limit the process. Those skilled in the art may readily modify the process or transfer it to other cases without inventive change. If such modifications fall within the same scope of claims or similar technologies as the present invention, the invention is intended to encompass such modifications.

Claims

1. A method for preparing fluorescent glass for high R14 warm white LED, characterized in that: The specific steps are: Step 1: Mix 4-10 parts of orange phosphor, 4-10 parts of green phosphor, 20-32 parts of commercial glass powder, 0.8-1 part of dispersant, 1.6-2 parts of epoxy resin, 0.1-0.3 part of curing agent, 60-80 parts of zirconium oxide balls, and 10-13 parts of deionized water according to the mass ratio; Step 2: Commercial glass powder, orange phosphor, green phosphor, epoxy resin and dispersant are mixed evenly to obtain powder raw materials. The powder raw materials are added to deionized water in three batches, and then zirconium oxide balls are added and ball milled for 6 to 8 hours to obtain fluorescent glass slurry; Step 3: Add curing agent to the ball-milled fluorescent glass slurry and ball-mill again for 15 to 30 minutes to mix and react fully, and then perform vacuum degassing treatment to finally obtain a fluorescent glass slurry with high solid content and low viscosity; Step 4: Pour the prepared fluorescent glass slurry into a mold, place the mold filled with the slurry in a constant temperature and humidity box for 1 to 2 days to set, and then place it in a dry place for dehydration and drying for 1 to 2 days to obtain the fluorescent glass blank; Step 5: Place the prepared fluorescent glass blank into a muffle furnace for debinding and sintering, and then polish to obtain a finished fluorescent glass product for high R14 warm white light LED.

2. The method for preparing a fluorescent glass for a high R14 warm white LED according to claim 1, characterized in that: In the first step, the orange phosphor is GdYAG:Ce phosphor, the green phosphor is GaYAG:Ce phosphor, the commercial glass powder is commercial low-temperature glass powder, the dispersant is ammonium polyacrylate, and the curing agent is one or more of polyethyleneimine, polyetheramine, and cardanol-modified phenolic amine.

3. The method for preparing a fluorescent glass for a high R14 warm white LED according to claim 1, characterized in that: The powder in the second step is added to deionized water in three batches, with a time interval of 1 to 2 hours and a mass ratio of 4:2:1 to avoid adding too much powder at a time to cause agglomeration.

4. The method for preparing a fluorescent glass for a high R14 warm white LED according to claim 1, characterized in that: In the third step, the rotation speed of the vacuum defoaming machine is 1000-3000 r / min, and the time is 1-5 minutes.

5. The method for preparing a fluorescent glass for a high R14 warm white LED according to claim 1, characterized in that: In the fifth step, the humidity is maintained at above 80% for 1 to 2 days during shaping, and the temperature is maintained at 20° C. to 30° C. during drying for 1 to 2 days.

6. The method for preparing a fluorescent glass for a high R14 warm white LED according to claim 1, characterized in that: In the sixth step, the debinding process is to heat the material from room temperature to 600-700°C at a heating rate of 1-8°C / min, and keep it at 600-700°C for 45-90 minutes. The sintering process is to heat the material from room temperature to 700-900°C at a heating rate of 6-10°C / min, keep it at that temperature for 15-30 minutes, and finally cool it with the furnace.

7. Fluorescent glass for warm white LED with high R14 prepared according to the preparation method of any one of claims 1 to 6.

8. The method for preparing fluorescent glass for warm white LED with high R14 according to claim 2, characterized in that: The commercial low-temperature glass powder is a commercial glass powder with a melting point of 600°C.

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