Gold Eletrode NTC Thermistor Chip Take Light Rate Package Structure and Process
The role of light color phosphor in compound, form white light. Its main characteristics including grain size, shape, semiconductor thermal efficiency, conversion efficiency, stability (heat and chemical), among them, the semiconductor thermal efficiency and conversion efficiency is the key. Research shows that, with the temperature rises, phosphor quantum low efficiency, reduce the light, radiation wavelengths will also be changing, and cause the white light NTC thermal gold electrodes chip/silver electrode chip color temperature, the change of the color and the higher temperature will accelerate the aging of phosphor. Reason is that the phosphor coating is by epoxy or silica gel and phosphor deployment and become, the cooling performance is poorer, when moving or by ultraviolet radiation, vulnerable to temperature sudden destroyed and aging, semiconductor thermal low efficiency. In addition, high temperature and potting glue of phosphor thermal stability problems. Due to the commonly used in 1 um above phosphor size, refractive index is equal to or greater than 1.85, and silica gel refractive index generally in 1.5 or so. Because do not match between the refractive index, phosphor and particle size light scattering far limit (30 nm), so the phosphor particle surface exist light scattering, reduce the light efficiency. Through adding in silica gel nano phosphor, can make the refractive index increased to 1.8 above, reduce light scattering, improve thermal NTC gold electrodes chip/silver electrode chips out light efficiency (10% 20%), and can effectively improve the quality of light color.
The traditional phosphor coating way is to phosphor and pouring sealant was mixed, then click coated in the chip. Due to the lack of phosphor coating thickness of the shape and precise control, causes a shoot the light color not consistent, appear blue or partial partial wall. And LumiNTC thermal gold electrodes chip/silver electrode chip company s development of the form coating (Conformal coating) technology can realize the phosphor uniform coating, safeguard the uniformity of the light color, as shown in figure 3 (b). But research shows that, when phosphor coating directly in chip surface, caused by the scattering of existence, a light low efficiency. In view of this, the United States RenssELaer institute presents a Photon scattering Extraction process (Scattered Photon Extraction method, SPE), through in the chip surface decorate a lens, and will contain phosphor glass from the chip must be placed in position, not only improve components reliability, and greatly improve the efficacy (60%), as shown in figure 3 (c).
Overall, to improve thermal NTC gold electrodes chip/silver electrode chips out of light efficiency and reliability, encapsulation sub have gradually by high refractive index transparent glass or microcrystalline glass replace trends, through the will in the mixed or phosphor coating on the glass surface, not only improve the evenness of phosphor, but improve the encapsulation efficiency. In addition, reduce NTC thermal gold electrodes chip/silver electrode chips out the direction of the light optical interface number, also improve the efficiency of the light out effective measures.