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CRT projector
From Wikipedia, the free encyclopedia
A CRT projector is a video projector that uses a small, high-brightness CRT (or picture tube) as the image generating element. The image is then focused and enlarged onto a screen using a lens kept in front of the CRT face. Most modern CRT projectors are color and have three separate CRTs (instead of a single, colour CRT), and their own lenses to achieve colour images. The red, green and blue portions of the incoming video signal are processed and sent to the respective CRTs whose images are focused by their lenses to achieve the overall picture on the screen. Various designs have made it to production, including the "direct" CRT-lens design, and the Schmidt-CRT, which employed a phosphor screen that illuminates a perforated spherical mirror, all within an evacuated "tube."
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- Long CRT life, typically that of a normal television picture tube.
- Can achieve good to very good colour resolution, brightness and picture size.
- Once set-up, minimal maintenance is required, unlike projectors that use lamps.
- Superior black level - black is actually black and not dark grey.
- As with CRT monitors, the image resolution and the refresh rate are not fixed but variable within some limits. Interlaced material can be played directly, without need for imperfect deinterlacing mechanisms.
- Unrivaled Video Fidelity, Images are free of raster lines, unlike high end LCD projectors, DLP projector cold have a visual rainbow effect on some people with their persistance of vision. People seeing this distortion when viewing DLP can only get used to it or change to a different type of PJ.
- Tends to be bulky and somewhat heavy (and non-portable) due to the CRTs.
- Brightness Inreases with Higher End units
- Suffers from being undervalued in todays home theatre market compared to smaller plastic box PJs
- Focusing is not even on older systems without good setup, again due to the way the image is projected and requires sophisticated circuitry to compensate--- now found on newer generation crt projectors for quicker setup.
- Requires more time to set up and adjust for a good overall image for older crt projectors from the 1970s and 1980s.
- Costlier than other types of crt tubes for replacement but the tube life, rated in tens of thousands of hours, is extremely long.
- CRT Projector Primer/FAQ Find out why CRT Projectors are still used in home theaters where image quality is paramount.
- CRT Projector Manuals & Setup tips Hundreds of manuals and pictures showing board level controls and adjustments for the most popular projector models including Barco, NEC, Electrohome, Sony, Ampro, Zenith, etc.
- CRT Projector Discussion Forum A forum to ask CRT projector questions from other enthusiasts and technicians.