Digital Cinema – Bringing Nanotechnology to a Theatre Near You
TI currently owns the digital cinema market (with about 120 installations) but Kodak appears to be challenging them. This article discusses how the technology will be applied to pre-show advertisements. With a digital system, theatre owners would be able to download new shows through a satellite link rather than sending cans of film back and forth.
TI’s technology, known as digital light processing, uses postage-stamp sized MEMS micromirror devices to reflect and direct the image onto the big screen. Powered by the Digital Micromirror Device, it contains a rectangular array of up to 2 million hinge-mounted microscopic mirrors. The bit-streamed image code entering the semiconductor directs each mirror to switch on and off up to several thousand times per second. When a mirror is switched on more frequently than off, it reflects a light gray pixel; a mirror that's switched off more frequently reflects a darker gray pixel. A color wheel provides a filter for red, green, and blue which when combined into a system with three color wheels provides over 35 trillion color combinations. In a three chip system, each chip handles one of the three colors providing a more efficient output.
Kodak also plays in this space and plans to use the D-ILA, or digitally driven image light amplifier, which uses a reflective liquid crystal display rather than micromirrors. In a D-ILA, the light from a Xenon light travels through a polarized beam-splitter, then through a projection lens and onto the screen. By using a reflective LCOS device, with a high aperture ratio and high-density pixels, the image blends together almost seamlessly providing a high-resolution image with film-like quality.
D-ILA technology provides 2048 x 1536 pixels on a 1.3 inch chip. Its CMOS design places the matrix addressing switches behind the light-modulating liquid crystal layer and not in front. This eliminates the “screen door effect” that comes with other matrix display technologies. While TI is ahead, the JVC technology Kodak uses appears to be a more complete system for capturing, storing, and displaying content.
For those buying a home TV, the choice between DLP and LCD is still a close one. Check out this site for a comparison.
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Hall T. Martin