Research On Color Mixing Of White LEDs

As a new source for lighting, Light emitting diode is one of the most attractive technology fields in recent years because of its excellent characteristic such as superiority in power-saving, environmental friendliness, small size and long life. Due to the narrow spectra of LEDs, we should mix several color together to get white light. Several chromatic parameters are determined by spectral power distribution, so the purpose of this paper is to design the spectral power distribution of LED source based on Numerical calculation of color mixing, and to optimize the chromatic parameters such as CRI and LER. Generally speaking, the work of this thesis can be summarized as follow:1. Developed a color mixing simulation program based on the colorimetric theory and color mixing principle. With this simulation program, the calculation will be very convenient, and it can help to design the spectral shape of white LED source.2. Verified the simulation results of trichromats and quadrachromats to experimental results. It is well known that the general white LED sold in the market has a poor CRI because of the absence of red composition. Combining the red LED to white LED is a proper approach to improve the CRI. In this paper, a LED module has been created, by change the way of power supply, the module can produce high-CRI white light in different Correlated Color Temperature, and the test results were well agreed with the design value. Furthermore, the experiment based on four-color LEDs was completed and the results showed that the method is reasonable for calculation of four-color mixing.3. Optimized the white light spectrum composed of several Gaussian spectra. The peak wavelength, FWHM and number of Gaussian spectra are important factors, and the author optimized the parameters to get a excellent white source.