LED technology solutions with poor consistency _LED high color temperature and color rendering, poor technical solutions

by:Xinyao LCD     2020-04-09
LED consistency technology solutions for the cause of the poor: LED poor consistency produced mainly in the process, in blu-ray + YAG phosphors have white light way, YAG phosphors, because of its high density in encapsulation adhesive curing process so there will be a phosphor sedimentation is the poor consistency, LED technology solution causes: LED poor consistency produced mainly in the process, in blu-ray + YAG phosphors have white light way, YAG phosphors, because of its high density in encapsulation adhesive curing process so there will be a phosphor sedimentation phenomenon, due to the inconsistency subsidence, causes LED have off color, appear the phenomenon of light spot. Aiming at this problem, the industry at present is mainly by controlling the viscosity of encapsulation adhesive, control of the baking temperature and baking time to solve it, but it need good equipment and rich experience. On the issue, the current development of new technology has three aspects: 1. Preparation of phosphor glue cake first, and then put the cake paste in the chip surface by using the method of paste achieve LED encapsulation; 2. By sedimentation, spin, printing and so on will phosphors coated on the surface of glass substrate, then put the glass on the chip surface, realize the LED encapsulation; 3. Using nanoscale fluorescent material, as a result of nano fluorescent material particles larger than the surface area, density is small, so the nano fluorescent material in mixed with encapsulation adhesive and in the subsequent solidification process, the phenomenon of settlement of fluorescent material won't occur. Two high, LED color temperature and color rendering of technical solutions LED color temperature and color rendering problem in blue + YAG way a white light yellow powder is obvious, because it lacks red component, so the light source color temperature is very difficult to do below 4000 k, is only the highest color of around 85. Solution to the current development of the technology mainly include: 2. More than 1 to chip combination way to realize low temperature, high color rendering of white LED. Such as red as the 615 ~ 620 mm, green light for 530 ~ 540 mm, blue light is 460 ~ 470 nm chips is combined, the three groups or plus yellow chip, which can get different color temperature ( The lowest temperature can do 2700 k) , high color rendering ( More than 90) White LED and the LED luminous efficiency is better. But the problem is: the circuit is complicated; Red, green, and blue chip different light failure is different; When the chips light fever, sanki colours have different dominant wavelength drift; More focus for chip in a device, the heat will be more difficult; And I can't make the color of 3 kinds of LED light mixed well ( Figure 1 shows the RGB tricolor mixed sketch, only A zone is 3 kinds of color are some areas, so that only A zone is white light, other areas are not white) 。 Therefore, for the development of this technology, there are a lot of problems to be solved. The RGB tricolor mixed with light in figure 2. 2 phosphor conversion method. Is the blue LED chip at the same time stimulate the yellow phosphor, and red phosphors, by adjusting the proportion of phosphor in red, can get low colour moderate high color rendering of white LED. The advantage of this approach is that two kinds of phosphor powder mixing, blue, yellow and red LED devices are easy to evenly mixed color, whole space can get the expected device space chroma uniformity is good. Its disadvantage is that at present, the red phosphors quantum efficiency is low, to produce more red light must be absorbed more blue light, which leads to device components to reduce the spectrum of blue and yellow light, luminous efficiency of the device by almost half. 2. 3 with blue LED excitation yellow phosphor, with red LED to compensate, adjust the luminous intensity of LED chips and phosphor powder, color also can achieve low moderate high color rendering of white LED. Because the advantage of this approach is to avoid the low efficiency of the use, so the LED luminous efficiency is higher. The disadvantage is that driver circuit is relatively complex, but the technology is easy to implement. Because the blue light LED, fluorescent powder and red leds are relatively independent of the light, in the case of a single device possible space color is not uniform, but you can through the proper display configuration way to solve this problem. Figure ( 2) The QD Vision QDLED lamp 2 in the United States. 4 developing quantum dots LED QDLED) 。 QDLED is a relatively new technology is also hot. Quantum dot small particles ( Size within 10 nm) , excitation spectrum width, light color pure, and can be realized by adjusting the particle size of quantum dots in different light color change. With quantum dots as LED light-emitting materials, therefore, can be realized in blu-ray inspired by different color temperature and high color rendering. There are a lot of important research units have development in this field, such as the United States of QD Vision in 2010 launched a QDLED lamp ( As shown in figure 2) ; LG joint QD Vision developed quantum dots LED display. QDLED can not only realize the LED color temperature, color rendering is adjustable, and also because of the quantum dot small particles, so QDLED there is no problem of poor consistency, moreover QDLED energy saving effect is more obvious.
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