Laser TVs and projectors

I represent to Your attention the second part of the article about projectors and projection TVs. In the first part we met with history and development of projection equipment and now let's talk about the new technology used in projectors and televisions, built based on them. As before, I will try to tell everything as easy and available, so please do not scold me for some technical "inaccuracies" in the description ab

  • Projection televisions and projectors Micromirror device (DMD or DLP)
  • One of the newest and most innovative developments produced by the company Mitsubishi is a projection TVs and projectors using the Micromirror technology DLP ay with this technology, there projection TVs, with screen sizes up to 92 inches, and it's almost 2.5 m ai

    Laser TVs and projectors

    The technology DLP - optical semiconductor and digital Micromirror device (DMD, in 1987 year invented Larry Hornbeck of Texas Instruments. DMD chip is a matrix consisting of a large variety of microthermal are not only able to reflect them arriving on the luminous flux, but also to change the direction of reflection, about the same size of the chip can be judged by photo:

    Technology DLP Micromirror chip

    Every microcircula – a tiny piece of aluminum the size of 10x10 microns, it corresponds to one "pixel" of the image. You can calculate that to permit HDTV (1920x1080) need more than two million such microthermal. On the picture You can see part of the design, consisting of two microdermal every microthermal can change the angle, turning one or the other side (two positions)

    Microthermal

    For fans of "dig deeper", microthermal "in the cut". The mirror is mounted on a relatively massive platform, which is attached to more thin and more flexible than other parts of the system, strip the suspension, stretched between the supports. In the other two corners of the base not occupied the supports are arranged electrodes, which, due to the Coulomb force, I can pull one of the edges of the mirror. Thus, the mirror can be tilted in one and in the other direction at an angle of about 10-12 degrees

    the working Principle of a Micromirror chip

    But looks like the foot of an ant ordinary (small) climbed on the crystal, not broke he would, because he is very expensive: several thousands of babailov, however, ad

    Foot ant and microthermal

    Let's consider the principle of operation of a Micromirror the DMD of the chip. The light from a powerful lamp falls on the mirror, each of which received the control signal to turn one or the other side. Those mirrors, which at the moment should not "Shine", turn around and reflect incident light in the direction of a special absorber (anything black, from which rays are not reflected), and the rest - reflect the light flux on the optical system (lens) and projected through it on the screen, zasvechivaya the desired point (pixel) of the image

    DMD chip in

    So we get "black" and "white" point. which make up the image. But what about the shades of grey? To receiving them every microthermal able to vibrate, changing their position to thousands of times per second, thereby adjusting the quantity of the reflected light and providing a huge number of shades of gray. Now let's talk about how to get a color image. Remember the article about color TV with the manual getting color? all the same: mechanical wheel with colored filters bs

    Mechanical wheel with colored filters

    The simplest design is with three filters of primary colors (red, green, blue), however, for the best obtain the "white" color and the other color tones, used a more complex wheel designs, with the number of filters from four to six:

    Mechanical wheel with colored filters

    Mechanical wheel, which, of course, is synchronized, rotating at speeds up to 9000 rpm (up to 150Hz), providing a color light flux from the lamp in each of the colors of filters. DMD Micromirror chip reflects alternately each of these color streams and projects them through the optics of the screen and the absorber. Ie, images in each color (according to the filter on the wheel) are displayed alternately, the task of our eyes and brain try to model them into one continuous color picture bm

    the principle of the wheel with light filters

    Despite the high brightness, contrast, sharpness and good colour reproduction of the received image, for our eyes is extra burden, they are used to see color picture at once, and we "feed" colorful fake, so they still notice colored plumes and the rainbow in the image, the very same DC flicker - also not conducive to the preservation of view ac of Course, you can use trichopoulou design to reduce the number of flashes (similar to 3LCD), but this solution leads to a significant appreciation of the final product in 2-3 times and this is highly relevant to the buyer's pocket bn

    Projector filters

    The main problem with all projectors is the lamp. The lamp gets very hot, so you need a powerful and noisy fan for heat dissipation. In addition, the lamp has a short life span (200 hours) during active operation of the projector, it is enough just for a year, and it is up to half the price of the projector (though there are projectors that are sold with spare bulbs)

  • Laser-led DLP projectors
  • The problem of fragility, and high power consumption and necessity of constant severe cooling of the bulbs, tried to solve a firm Casio with the introduction of laser-led DLP projectors. Instead of the lamp, using a green led and a blue laser. The green color was due to reflection of the laser beam from the rotating mechanical wheel, which part (1/3) was coated with a special phosphor

    Laser-led DLP projectors

    This design significantly reduces power consumption, but the flicker effect, due to the mechanical wheel, still had a place

  • Laser DLP projectors
  • Laser projection systems have neither lamps nor LEDs: does everything laser, rather the laser unit. Light source Necsel presented on the figure looks like a combination of green, red and blue lasers, which are able to project powerful beams of light directly on the Micromirror chip

    Laser DLP projectors

    This block has many advantages: no need to polarize the light for its subsequent decomposition, no mechanical wheels and filters, low power consumption and longer service life. Built-in switch itself turns on and off the laser of the right color, but the image projected on the screen still not full color, they are still three (red, green, and blue), therefore, the task of the eye to pull it all together - remains bk

    DLP projector

    The perfect way out of this situation - trehmatrichnye system with independent lasers, in this case the effect of "flicker" is minimized as the laser of each color operates directly on its Micromirror matrix, the only negative - the cost of the projector

    Trehmatrichnye system with independent lasers
  • Pico projectors
  • Pico projector - this projector is small (pocket) size, which can be embedded in the camera, phone and even a watch ab2003 year, the Israeli firm Sony announced the intention to develop the pocket projector format, and the first public demonstration of the product took place in October 2006 year

    Pico projectors

    Pico projector built into the mobile device can be used for viewing photos, video resolution larger than the screen device. For energy saving (that didn't have a backpack with battery to carry ap ), projectors operate on the led light source

    Link to this story: http://en.rem-tv.net/publ/3-1-0-56

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