The Study Of Chromaticity Control Technology Of LED Light System

LED industry is growing continuously in recent years,LED is more popular in general lighting due to its advantages of high luminous efficiency、adjustable in brightness、easy control、long service life、rich colors、etc.With the development of technology and improvement of requirements for people’s quality of life,People pay more attention in adjustable in color temperature、high color rendering index、LED intelligent lighting system.According to the disadvantage for LED applications such as inaccurate adjusetment for color temperature、poor color rendering、inconvenient control method,we conduct a more complete theoretical analysis and conduct experiments in four aspects:the method for obtain adjustable color temperature by mixing warm and cold white LED、improve color rendering index by multi-color LED chips、the method for obtain width adjustable color temperature and high color rendering index white light used WRGB-LED module、design of interior lighting control system。The main work have been completed includes the following projects:1)Study on the photometric and colorimetric theoretical model of two channels’ PWM based on mixed light source of the two kinds of white LED with different color temperatures,deducing the formula for chromaticity coordinate of mixed light source、correlated colour temperature、maximum luminance and ratio of duty ratio of two channels’ PWM.Two white LED samples of low color temperature(3282K) and high color temperature(12930K) were mixed in experiment,changing the duty ratio by controlling the pulse width.The results show that the experimental results are in fairly good agreement with the theoretical value,proving the correctness of the theoretical model.2)Study on improving color rendering index by multi-color LED chips,write parameter simulation software for mixed white based on the colorimetry method.Imported the spectrum of cold and warm white light sources and single-color LED light into the program for simulating calculation, working out the maximum value of color rendering index of the synthesized light source under different color temperatures as well as corresponding matching quantity of various LEDs. The results showed that: the synthesis between warm white LED and red, green and blue LED could lead to white light which color temperature falls in the range of 3500 K to 12300 K and color rendering index Ra ranges between 92.0 and 97.7; the synthesis between warm white LED and red, green and bluish-green LED could lead to low color temperature white light(3500K-4500K) which color rendering index Ra ranges between 95.0 and 97.8; the synthesis between cold white LED and red, green and bluish-green LED could lead to high color temperature white light(8200K-13000K) which color rendering index Ra ranges between 90.9 and 98.4. An actual preparation was conducted following the calculated LED matching quantities to produce LED with 7992 K color temperature and 97.1 color rendering index Ra. Actual measurement showed that the produced LED had a color temperature of 7992 K and a color rendering index Ra of 97.1, well matching the theoretical calculation.3)Study on method for width adjustable color temperature and high color rendering index white light used WRGB-LED module,We mixed white LED with red、green、blue LEDs, and use pulse width modulation,at the same time optimized the ergodicity scope. The process finally obtains LED synthesized white light with high color rendering and wide adjustable temperature.Conducted the experiment according to the simulation results,obtained the mixed white light which have wide adjustable temperature(between 2572 K to 12585K)、and high color rendering index(between 93 to 96),and the average temperature change interval is193 K.4)Study on the indoor lighting control system based on Zigbee、Wifi,completed hardware and software design of system,designed computer lighting control software,introduced algorithm of RGB-mixed light、adjustment of color temperature、CRI Optimization,realized remote control, color temperature adjustment, brightness adjustment, color change and other basic functions of LED lamps.