Preparation Of High Color White LED And Study On Adjustable Color Temperature

In recent years, with the advancement of technology, LEDs as a new generationof green light, gradually are applied to the field of general lighting. Due to demandingfor LED in the lighting area, the article is focused on exploring how to prepare highpower white LED with low color temperature and high color rendering, and states atheory to achieve tunable color temperature by different color temperature LEDsmixed, then researches the changing of the spectrum, color temperature, colorrendering index after blending.The contents of this paper are:1. Briefly describe the basic theory of the photometric, chromatic, electricalparameters of LED. Emphasis on discussing the calculation methods of colortemperature and color rendering index, and analyzing the importance of the colorrendering index of white LED in lighting applications.2. Discuss the preparation methods and the development of white LED with low colortemperature and high color rendering index, focuses on analysis of photometric,chromatic, electrical parameters of this white LED, and points out the difficultpreparation technology on this white LED. The experiment is studied on preparationof white LED with low color temperature and high color rendering usingInGaN-based blue LED chip to stimulate yellow phosphor (YAG: Ce3+), greenphosphor (silicate compounds) and orange-red phosphor (nitrogen and oxygenamixture of compounds), selected the appropriate ratio to analyze the effect of thewhite LED prepared. Studies have shown that: yellow, green, orange-red phosphor aremixed with reasonable ratio to achieve the purpose of high luminous efficiency andgood color rendering index of white LED under the low color temperature condition.3. for the revolutionary development trend of LED in the field of intelligent lighting,as well as the demand for different light effects in the same space, and sum up themethods to achieve tunable color temperature at home and abroad, states that differentcolor temperature of white LEDs are mixed to realize tunable color temperature.Concentrated on the tunable color temperature, the experiment uses a low colortemperature (2700~2900K) and high color temperature (7000~8000K)of twowhite LED samples for series and parallel blending, studies mixing white lightspectrum, color temperature and color rendering index, calculates and verifies through the white LED spectrum mathematical model. Studies have shown that the meansquare error is basically the same between experiments and theoretical calculations ofspectra; Mixture in parallel led to a larger extent of tunable color temperature than inseries, the range is2700to6000K; The color rendering index of mixed white lightare good in series and parallel; While the color rendering index remain above80inseries, the color rendering index maintain at75above in parallel. Under the conditionof tunable color temperature, seriously focuse on the color rendering index throughexperiments using a low color temperature (2800~3000K),(3000~3400K) andhigh color temperature (7000~8000K) of three white LED samples in series andparallel mixed, studies have shown that: the range of color temperature of mixedwhite LEDs was3000K to7000K;When low color temperature of white LEDs withcolor rendering index exceeding66and high color temperature of white LEDs withcolor rdndering index exceeding87were mixed,white light with good color renderingindex exceeding75can be got in the color temperature tunable range.