The DLP back throws technical DLP (Digital Light Processing) to refer to the digital light processing technology, this kind of technology must the first phantom signal after the digital processing the projection comes out again, its projected display quality is very good. The transmission type image formation which throws with the LCD back is different, DLP is the reflection way. Its system core is digital micro mirror component - DMD which TI (the Texas Instruments) the company develops (Digital Micro mirror Device), DMD is demonstrated that the digit may regard the information the final link, it is in the CMOS standard semiconductor system regulation, in addition adjustable changes the reflecting surface the rotary mechanism forms . Usually the DMD chip has the micro mirror which the approximately 1,300,000 hinges install, a micro mirror corresponds a picture element. The DLP back throws the principle is integrator (Integrator) uniformizes with the the photo source, has the color tertiary color color link through one (Color Wheel), divides into R, G, B the light tricolor, when micro mirror to photo source incline, the light reflects to the lens on, is equal “opens” the condition in the light switch. When micro mirror to photo source counter-side to incline, the light does not reflect on the lens, is equal in the light switch “the pass” the condition. Its density step by each second light switch, switch the number recently decided. Therefore uses the synchronized signal the method, the processing digit revolving lens' electrical signal, transfers the gray scale the continual light, coordinates R, G, the B three kind of colors, but displays the color, finally projects the image formation, then may have the high quality, the high density step image.