Spectrum shows relative to the wavelength of light and the distribution of light intensity. The LED spectrum is commonly monochrome LED, such as the blue LED use 470nm wavelength as peak present peak distribution, with the peak shorter wavelength ultraviolet areas and peak longer wavelength green areas for the determination limit of the luminous intensity. while the incandescent lamp spectrum, the luminous intensity is widely distributed in more than 400 nm blue areas near to 700 nm the infrared field, in the field of ultraviolet and infrared field luminescence intensity can also be observed. Fluorescent lamp, use a combination of phosphor luminescence wavelength part is the peak of the spectrum.
With ordinary red, green and blue LED spectral peak only one can be compared，the spectrum of the white LED has a quite different. Such as blue and yellow areas have two luminous intensity peaks, or in the blue, yellow and red areas have three peaks, or there will be even more peak. This is because, the white light of white LED is combination multiple wavelengths light. For example, when combination with blue LED and yellow phosphor, peak appears in the blue areas and yellow areas. In addition, based on the peak of blue LED luminous intensity sharper, and based on the fluorescence peak more gently.
When use LED to LCD back light, ideally LED spectrum in red, green and blue three areas appear luminous intensity peaks. This is because the LED light eventually through the liquid crystal panel color filters (red, green, blue) output to the outside.
To get three luminous intensity peak, use red, green and blue three methods of LED, and by improving the fluorescent material, using can obtained three peak of method of white LED.