Process method for producing rare earth eutectic phosphor by edge-defined film-fed crystal growth method

Abstract

The invention discloses a process method for producing a rare earth eutectic phosphor by an edge-defined film-fed crystal growth method, and relates to preparation of eutectic phosphors. The method comprises the processes of raw material pretreatment, lower thermal field assembly, upper thermal field assembly, vacuumizing and inflation heating, seeding inoculation, shouldering, equal-diameter growth, pulling-off cooling, exhausting/crystal taking-out and the like. The rare earth eutectic phosphor can be prepared by the process method, and compared with fluorescent powder in the prior art, therare earth eutectic phosphor has the advantages that the performance is improved in multiple aspects and the application range is wider.

Description

technical field [0001] The invention relates to the preparation of eutectic phosphors, in particular to a process method for producing rare earth eutectic phosphors by a guided mode method. Background technique [0002] Due to the characteristics of high luminous efficiency, low power consumption, long service life, strong safety and reliability, and environmental protection, white LEDs have been used in many fields such as display screens, automobile industry, backlight sources, roads, homes, and landscape lighting in recent years. has been widely used. [0003] The traditional white LED is obtained by mixing the yellow light generated by the stimulated radiation of the blue chip + Ce:YAG phosphor to obtain white light; in the traditional packaging structure, the phosphor is dispersed in the transparent resin in the form of particles, which has the following disadvantages: [0004] 1) The refractive index (1.83) of Ce:YAG phosphor particles is quite different from the refr...

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Problems solved by technology

[0004] 1) The refractive index (1.83) of Ce:YAG phosphor particles is quite different from the refractive index (1.4-1.6) of silica gel and resin, and strong scattering will occur when the light enters the phosphor powder glue (the difference in refractive index between the scattering interfaces The larger the value, the stronger the light scattering), resulting in a decrease in the luminous efficiency of the chip and waste heat;

[0005] 2) Factors such as the shape and particle size fluctuations of the phosphor powder, uneven coating thickness, and precipitation during the dispensing process will lead to inconsistencies in LED color temperature and other parameters, which require additional binning processing, which will increase the process and cost;

[0006] 3) Since the maximum operating temperature of silica gel is generally 200°C, the performance will deteriorate after long-term use, and even turn yellow and crack, reducing the service life and reliability of the LED

[0010] Pulling method, also known as Czochralski method, abbreviated as Cz method in English, is the most popular bulk single crystal growth technology at present. The traditional pulling method device consists of heating system (heating, temperature control and heat preservation), atmosphere control system (vacuum , gas circuit, inflation), transmission system (lifting, rotation), etc.; the advantage of this method is that it can test and observe the growth interface, directional seed crystal, "necking" technology, "finishing" technology, so it is easy to control and can Obtain faster growth rate and high uniformity of product performance, so the yield rate is much higher than other crystal growth methods; due to the importance of the pulling method, more patents have been applied for at present; for example, Chinese patent application CN102560655A discloses a The sapphire crystal growth furnace adopts the Kyropoulos sapphire crystal growth process to realize the large-scale production of sapphire crystals with a diameter greater than 250mm; another example is the Chinese patent application CN103741208A which discloses a crystal growth furnace by the pulling method, which can effectively control the pulling process. The three-dimensional effect of flow and heat transfer in the furnace chamber of the method organizes a better temperature environment around the crystal, and at the same time makes the solid-liquid interface in a better temperature gradient during the crystal growth process; this new furnace chamber structure can reduce the crystal growth. Dislocations or cracks during the process improve crystal quality; however, none of the existing crystal growth furnaces mentioned above are well suited for the manufacture of rare earth eutectic phosphors developed by our unit

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