Spectrum is the relative distribution of wavelength and light intensity. The spectrum of LED is generally monochromatic LED, such as blue LED with a peak wavelength of 470nm, with shorter peak wavelength ultraviolet area and with longer peak wavelength green areas as the determination limitation of light intensity.
And the spectrum of incandescent lamp, its luminous intensity is widely distributed in the blue area 400nm to 700nm near infrared field, in the field of ultraviolet and infrared can also observe the luminous intensity. As for Fluorescent lamp, the part of combination usage’s phosphor light wavelength is the peak of the spectrum.
Compared with the ordinary red, green and blue LED spectral peak, the white LED spectrum is different. For example, there are two luminous intensity peaks in the area of blue and yellow, or in the blue field, yellow and red fields, there are three peaks, and even more. This is because the white LED white light is a combination of multiple wavelengths of light. For instance, a combination of blue and yellow phosphor LED, the peak is in the blue and yellow field. In addition, based on the blue LED luminous intensity of peak is sharp, and the phosphor peak is relatively flat.
When the LED is used in the liquid crystal panel back light, the most ideal situation is that the spectrum of LED appears luminous intensity peaks in three areas of red, green and blue. This is because the LED light will eventually be output to the outside through the liquid crystal panel of the color filter (red, green, blue).
Getting three luminous intensity peaks, using red, green and blue three kinds of LED, and through improved phosphor material, use method of obtaining three peak of white LED.
The lighting of blue LED and YAG phosphor, blue LED and ZnSe single crystal plate, UV LED and RGB phosphors and white LED light spectra and fluorescence light and natural light. Although they are white, but the emission spectrum is different, on the other hand, when LED is used for ordinary lighting apparatus, the white LED will be more popular where the spectrum is widely distributed in the visual field. The reason is that close to the natural light, when the spectrum of the sun’s rays illuminates the object, the color of the object is close to the nature of the exposure to light.