Also, by using a specific wavelength for the backlight, engineers can design more efficient polarizing filters than they can when working with the broader spectrum of white light used in a traditional LCD panel. Researchers predict that these improvements could result in a panel that s 50 percent more power-efficient than a traditional LCD panel. When Texas Instruments introduced its DLP projection engines based on its micromirror panel designs, industry watchers hoped that the new technology would result in brighter, more portable projectors. One reason for this optimism was that DLP relies on a reflective panel, so there s no loss due to a light-absorbing panel, as with LCD panels. But due to the loss of light in a part of the projector other than the panel, initial products based on a single DLP panel were of about the same brightness as competing LCD designs.
Efforts are now underway to even up the score.
A spinning color wheel was placed between the light source and the micromirror panel. The wheel was divided into segments of red, green, and blue. The pixels on the panel were adjusted so that only the desired pixels would be projected when the wheel transmitted light of a specific color. The projectors created and displayed the red, green, and blue images so rapidly that the human eye perceived them as a single, full-color image. The problem was that the colored filters on the spinning color wheel worked by blocking all but the desired color, which meant that light was subtracted.