【 Weak current College 】 DLP big-screen television display principle and debugging methods---Power By 【 China power house network 】

Big-screen television display can give viewers even more shocking, lifelike picture with television audiences on TV screen picture quality requirements, big-screen television display in literature, news, topics, and other programs of more and more widely.
Currently, large screen TV wall there are three categories: CRT TV wall, LCD TV and DLP TV wall to wall.
CRT projection for RGB three shots, and current TV Imaging principle similar to the way for liquid crystal display LCD, DLP digital electronic micromirror projection mode. These three TV wall imaging, advantages and disadvantages as well, so applications can also vary.
Early television using DMD optical system, through the projection lens for large-screen image JDLP projection system mainly includes there is signal storage, DMD, lighting, filters and beamsplitter, projection lens, etc. Its core segment for DMD, control the generation of digital images. in a DMD has 848 minus instrument old = 508800 rotating aluminum alloy micro-mirror, each micromirror corresponds to one pixel. Each micromirror has independent control of light on/off capability, allowing light to pass, the "open" micro-mirror, then rotate + l0a, not allowing light to pass, micro-mirror ' ", then rotate a 10a, not into one Typ, micro-microscope is 0 °.
TV wall typically CRT, this TV wall technology mature, widely used, but it was irreparable defect is brightness lower, in a single, intermediate light, dark corners. LCD dependent polarization, 50 per cent of the light source for optical effect because polarization could not enter the human LCD, brightness or improve a lot, and the image is clear and white vertical bars are generally not used for television. DLP is currently the most advanced, and most suitable for television. No matter which kind of large-screen TV in the wall, in the Studio application, has its peculiarities, following the principle from the DLP, the discussion in this special environment of debugging method.br>DMD micromirror rotated under control of digital video signals, digital video signal is constant-amplitude of the pulse width modulation, pulse width size to control the micro-lens on rays make-and the length of time. Micromirror remain in ' ' open "status for longer, then the mirror that the brightness of the pixels. Because micro-mirror "open" and "gateway" between the conversion speed is very fast, so images don't see Flash, using micro-mirror this rapid conversion to grayscale pixels to control and color level. DLP light rays through the optical system is booting, projected into the DMD in DMD, is in the "open" status of micromirror will reflect light through the projection lens on the screen to form a square pixel, so the entire DMD "open" State micromirror projection via reflection, is formed on the screen.
A number of distinctions between DMD DLP has three different modes, i.e., single-chip DLP mode, two-, three-chip DLP mode mode, three-chip DLP DLP mode offers the highest brightness, single-chip DLP mode, white light sources through the condenser focus to tap on the color wheel, the wheel by RGB tricolor filter, by Ray irradiation after the color wheel to DMD, along with the rotation of the wheel Division, RGB order three light will irradiate DMD, a color wheel and RGB tricolor signal synchronization, that is, when the red light exposure to DMD DLP system processing time, red light signals; the same blue or green light irradiation to DMD, system for treatment of Blu-ray or green signal. In this way, people will be visible to the RGB tricolor signal combinations and feeling for color images. Use RGB tricolor minutes color wheel, white light sources of light will have 2/3 be filter absorbs (because only through a primary colors of light), it is in this mode, black and white projection brightness is 3 x color projection. In the third movie mode, no longer need to tap the color wheel, light from light Prism into RGB trichromatic, simultaneous output to three DMD, three DMD chip RGB trichromatic respectively deal. Compare with single-chip DLP, each color image was extended to three times, so that the light output is increased to three times. Since image for longer, enables higher levels of gray (such as 1obi strokes, up to 10 Chau-class), this will further improve the image quality. This mode is suitable for large-screen projection and high brightness.
Two slices of DLP projectors use patterns of metal halogen lamp as the light source, its DLP output spectrum in a relatively small amount of red light. Two pieces of single-chip DLP mode using the DLP mode separations filter system and three slices of DLP pattern beam separation system that neatly solves the metal halogen lamp output spectrum red light is too small. Two slices of DLP using magenta, and yellow color filter, magenta filter allows Red and blue light through, yellow filter allows Red and green light through, so that the red light will light long-pass filter, and Blu-ray, and interlaced by Green will. -Pass filtered light, the light will shoot to a two-color beamsplitter group, separated from the red light is projected onto d Mei DMD, blue and green alternate projection to the other pieces of DMD. Compared with single-chip DLP DLP, two pieces of a balance as possible in order to force the colour temperature of Yi a really restore the color in the Studio, the luminous body is no sunlight into light., the light color temperature 3200K are standard, therefore, also be sure to set the camera to 3200K stalls.
However, the DLP big-screen display, the light source is used in the halogen lamp, 6500K color temperature, and sunlight are basically the same, if not the color temperature to 3200K, camcorder, TV in the large-screen image is the blue image, it is clear that this is not what we want. We all know, the color temperature is indicated light spectra composition concept. Iron, tungsten, and other standard blackbody from absolute zero start heating temperature increase, as the black experience under color of visible light, the light color with the gradual increase in temperature changes. When it is heated to 800K, bold dark red light appears; re-heating, dark red becomes yellow when heating to 560OK, color from yellow to white in sunlight, the sun light, the approximate; continue warming to 2500OK, color gradually from white to blue in the TV program production, people always want to screenScene, people, accurate color reproduction, vivid guaranteed high quality color screen. To do this, the light source color balance is an important condition for color reproduction of the color balance in one of the so-called, refers to the use of light colour temperature and colour temperature of the camera, the same scene in different light source color temperature.
The camera itself has three completely filter to choose use 3200K stalls, first, second, light film 5600K daylight film, three stalls is 5600K + 1/4ND (ash tablets side stalls in film. Camera shooting with what color temperature, depending on the subject and its surrounding environment of color temperature. Camera in low color temperature, and photos of objects and the surrounding environment as high color temperature, then shooting out of the blue in the second camera images in high color temperature, and photos of objects and the surrounding environment is low color temperature, then shooting pictures too red. Therefore, the camera's colour temperature stall and shooting object and the surroundings of color temperature as possible consistent, big-screen television display debugging through computer RS232 interface and Fox ra-Vision software, debugging methods, divided into two classes of second-row, field phase adjustment and the adjustment of video decoding system.
1 row, field phase adjustment when the big-screen television display mechanical adjustment after the first line, field phase adjustment. It determines the screen between the concatenation is correct.Specific process is: first lose people tick round video signal. Large screen display for combination with a ruler. measurement and observation, the grid horizontal even kin directly not to lost distortion by the circle and the center of the home screen
2 video decoding system for adjusting video decoding system adjustments related to the large-screen image contrast, brightness, color temperature, nonlinear distortion, tone and color saturation. These indicators of adjustment with the observation of the method is not appropriate for us to adjust the test chart. Block diagram of the camera settings in 3200K, in the following debugging method, single and group Desk screen to adjust the alignment of single camera when single-break and Center vertically and single, each monomer show full image; adjust the composition Panel, the combination of screen display full image, camera alignment group Desk screen center location. To prevent the camera position and the impact on the large screen of the error, try to let the camera placed farther away. Adjust the brightness in the software; black level adjusting contrast,; each ladder level range is wrong, just tune Gamla correction. These three indicators are interrelated, the adjustment to be repeated until satisfied. Adjust color temperature, large transportation person white signal, in RGB adjust menu, first R to maximum (because the light source color temperature 3200K for 560OK, corresponding to the red light is less), and then under camera in the color temperature, vector white point of the oscilloscope in position and color monitor of subjective evaluation. G, B the two signals are repeated debugging until satisfied.
In the screen room's consistency adjustment, at least in the light of the screen, the other panel red light can not be redeployed to the maximum. Color and color saturation adjustment, large screen color bar signal, the discovery of human observation vector oscilloscope insulted one vector changed. Adjustthe contrast, brightness, and nonlinear distortion, lose one step wave signals, according to the oscilloscope display waveform. Rate does not, in amplitude and phase to adjust. In the above debugging, it is important to note that the screen between consistency adjustment. Various indicators of debugging are not isolated, they asked of all interrelated, so repeated adjustments are necessary.
Big-screen television display in Studio application, it is important to note that the color temperature adjustment. In the debugging process, relying on the computer and the naked eye is very difficult to achieve the desired results. So be sure to understand, on the basis of the principle of debugging methods to make the big-screen television display on the stage.