Liquid crystal light valve projector

 

    It uses the CRT tube and liquid crystal light valve as an imaging device , a CRT projector and LCD light valve combination product . In order to solve the contradiction between the image resolution and brightness , which uses external light, also called passive projection. Usually the light valve consists of three parts: the photoelectric converter , a mirror , an optical modulator , which is a controllable switch. CRT is irradiated by a light signal output from the photoelectric converter to the optical signal into an electrical signal continuously changing ; external source produces a beam of light, projected onto the bare valve , the internal reflection from the mirror , through the light modulator can be change its optical properties , the light valve immediately polarizing filter , the filtered light in the other direction , allowing only light with the optical slit by the same direction , the composite optical signal with a CRT , projected on the screen . It is by far the brightness, the highest resolution projectors, brightness up 6000ANSI lumens , a resolution of 2500 × 2000, applied to the ambient light is strong, the audience more occasions, such as ultra- large-scale command center, a conference center and large entertainment, but its price is high , bulky, difficult to repair shutters . The main brands are: Hughes -JVC, Ampro and so on.

 

    LCD panel projector

 

    It is a liquid crystal panel of the imaging device is a passive projection. Using a metal halide light source or external UHP ( cold light ) , put the light if the design of the LCD panel is formed of three RGB three beams by the beam splitter , respectively, is transmitted through the RGB tri-color liquid crystal panel ; signal source through the analog-digital conversion, modulation, to the liquid crystal panel , the liquid crystal cell to control the opening and closing to control the light path through the break , and then the combined optical mirror , the optical lens zoom, display on a large screen . Currently on the market common LCD projectors more popular monolithic design (LCD board , light without separation ) , this projector is small, light weight , operation, extremely easy to carry , the price is relatively cheap. But its lamp life is short, the color is not very uniform, lower resolution , the highest resolution of 1024 × 768, and more for temporary presentations or small meetings. Although this projector realization of the digital modulation signal, but the physical properties of the liquid crystal itself , which determines the response speed is slow, with the passage of time, the decrease in performance .

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