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To prepare the color temperature 2700-3500K, luminous flux greater than 82lm, while higher color rendering index Ra of 80,display signs, individuals that need to do the following: (1) accurate measurement of phosphor excitation and emission spectra, and to study the phosphor and chips emission spectrum of the matching; (2) control phosphor ratio, the low color temperature white LED with high color rendering to maintain a continuous spectrum; (3) choice of a good red phosphor, the luminous efficiency and attenuation control.
For high-power white LED spot, I personally think that the main improvement programs and the way the phosphor coating. The current way of phosphor coating are: conformal coating, spraying, evaporation, fluid dispensing, electrophoresis. 2008 Fifth China International Semiconductor Lighting Forum, Asymtek dispensing the company introduced the fluid (fluid dieing) of the phosphor coating method, which can not only improve the consistency of high-power white LED can also improve the product of the spot results.
At present, many domestic manufacturers to adopt the only way the general dispensing, so there will be a yellow circle and other undesirable phenomena spot. In addition, some engineers use to make spot changes spread powder evenly.
Second problem: the color coordinates and the correlated color temperature conversion relationship between how? A: According to CIE chromaticity diagram, we know: It is known to calculate the correlated color temperature and color coordinates, correlated color temperature can be calculated given isotherm.
So in the end the color coordinates and correlated color temperature conversion between the relationship between how to do? "Color Engineering" (Xi'an Jiaotong University Press, 1998), p. 102 describes Macamy color coordinates and color temperature on the conversion relationship,illuminated signage, with the following formula: (2-1) in the forward current of 350mA, driven by a big test power white LED,portable displays, the spectra shown in Figure 2.1. Dye measured coordinates (x,LED neon sign, y) = (0.3287, 0.3730), correlated color temperature is 5646K.