A tunable spectral system based on the effect of peak current on wavelength and its application in cell incubator

Research of photobiology is the hot spot of LED application. The LED tunable spectral lighting system can help experimentalists quickly set up the experimental light environment. To achieve flexible output of light conditions of different wavelengths, the system requires full coverage of the visible spectrum, which is based dozens LEDs with different wavelengths. In this paper, the spectrum of 17 different wavelengths of LEDs in the visible range was measured under different driving currents, and found that: with the change of current, the peak wavelength of 17 kinds of LED changed in different degree. Using this feature, the number of led required for spectral fitting can be greatly reduced.A double Gaussian addition model with current parameters was proposed in this paper to describe LED spectra under different driving currents. The experimental results show that the correlation coefficients of the predicted monochromatic LED spectra with different driving current are above 0.93. This paper also used the model to assemble white spectrum to verify the spectral fitting effect. Compared with the simulation fitting of 6000K sunlight by the same group of lamps with and without considering the effect of current, the spectral correlation coefficient increased from 0.89 to 0.94.Based on this method, a light cell incubator with variable spectrum was designed in this paper. The illumination system of the incubator is composed of 16-bit precision control module, driving module, display module and replaceable LED module. The current and duty ratio of each channel can be freely adjusted to meet the requirements of fast setting photobiological experiment environment.