Along with the projector product development, various factories unceasingly promoted have a higher brightness the projector product, projector brightness already achieve above 2,000 lumens, but in the user purchase process, common refuted to the projector brightness target understanding, the different brand, the same brightness target machine also differed in the comparison far, how then understood the projector brightness target?
"Light out" is the projector main technical specification, "light out" usually by luminous flux indicated, luminous flux is describes in the unit time the photosource radiative generation vision response strong and the weak ability, the unit is the lumen.
The LCD projector expression luminous flux unit is lumen, lumen is the survey projector luminous flux method which the American country standardization association formulates, it surveys large screen "the field" in glyph nine intersections each degree of illumination, while by the area, asks nine mean values again, namely for this projector lumen, the liquid crystal projector luminous efficiency mainly decides to photosource brightness and the path of rays system as well as the liquid crystal board transmission or the reflective power. At present the high brightness projector in does not increase the photosource power under the premise to raise the light use factor through the technology, establishes the P.S light on the path of rays to return board, will vibrate the polarizing eyepiece later vertical direction the S light reflection to change, P light transmission will enhance the light the efficiency.
Lumen is the Brightness unit of DLP projector. DLP (TI Technology) projector enlarges by the Digital Mirror Device (DMD) as the shutter imagery component the proceed signal, outputs the large screen picture. The majority DLP large screen projector all uses 1 DMD shutter piece, with filters the color piece to revolve the color.
The liquid crystal projector and the DLP projector are in the present China market the main machine kind, its brightness target as a result of the test environment difference, various brands machine Lumen target has a difference. But the factory provides the Lumen value has basically reflected the projector brightness level.
CRT The projector luminous efficiency indicated with peak value Lumen that, namely in a white window test picture, by the scan line still in the clearly discernible situation, surveyed the white window the greatest degree of illumination (LUX) while by the white window area (m2) to determine projector luminous flux, peak value Lumen had the very good practical significance, because you saw any video frequency picture was impossible completely all was the white field, the proportion which the white occupied generally occupies the picture area about 20%. Simultaneously the CRT projector is depends upon in the projection tube the electron beam to scan the gain picture on the fluorescent screen, the beam current size is decided by the negative pole launch ability, under the normal state the negative pole launches the electron by the cloudy grid between negative the potential difference control, is formed between the cloudy grid the electronic cloud, reduces along with the electric potential, the electron stream is very quickly pulled the anode - Fluorescent Screen, CRT the pipe can provide the higher pulse electric current, therefore on the window signal screen brightness may be higher, but if the picture is the entire white field, as a result of the negative pole launch ability limit, only can provide the average beam current, on the screen brightness can greatly reduce, only has the peak value flows when about 1/5. Because the negative pole each CRT projection and uses the window signal the size to be different (10%-25%), therefore various factories product brightness target, does not have the absolute commeasurability. projector brightness in the test and the user use, is away from large screen with the projector far and near and the large screen angle of view, the gain target has the very big relations, also is which needs to pay attention.