Digital Direct Drive Image Light Amplifier (D-ILA) and LCOS

Technology Overview & Description

Technology Overview & Description
One of the newest rear-projection display technologies, LCOS (or LCoS) is similar to LCD (HTPS) and consists of a liquid crystal layer which sits on top of a pixelated, highly reflective substrate. Below the substrate exists another layer containing the electronics to activate the pixels. This assembly is combined into a panel and packaged for use in a projection subsystem. Currently LCOS light valves are manufactured in 1280 x 768 (720p) and 1920 x 1080 (1080p) chip configurations.

LCOS is a reflective LCD display panel with high open area ratio. Basically, by placing the wiring area and switching elements under the reflection layer, there is no black matrix area – so it is possible to view a near-seamless image. LCOS systems can be created as 1 chip and 3 chip systems.

At the moment (meaning the next 15 minutes), LCOS technology is fairly competitive in terms of price and performance advantages compared to HTPS and DMD systems. Pixels on LCOS panels can be made smaller than is possible with other microdisplay technologies, without compromising picture quality or manufacturability. LCOS displays can be scaled to 1080i/p resolution (1920x1080 pixels) and beyond, without increasing the size and cost of the panel and other optical components in the light engine.

What’s Next
The future. Better, faster, cheaper. LCOS technology is still relatively expensive compared to LCD and DLP, but with Intel stepping up mass production this year that can be expected to change. According to Intel, in 2005 it will be possible for the cost of a single-panel LCOS light engine to drop below the cost of DLP and LCD light engines. This means that HDTVs based on Intel's LCOS technology may be less expensive than the competition.

Projectors
The D-ILA device, a special LCoS technology developed by JVC, and the LCoS technology used by Sony and Brillian, is a reflective type of LCD that delivers a greater amount of light than a transmissive LCD panel and is comprised of groups of pixels which correspond to each image dot. Also, unlike conventional LCD panels (in which the switches and electronics are mounted on the same surface as the pixels), the D-ILA 's driving IC substrate is located behind the liquid crystal layer. Because of this, the “screen door effect” found in many LCD projectors is eliminated almost entirely, leaving a nearly-seamless picture which is very impressive. D-ILA and DLP will be battling it out for the next several years, something that will undoubtedly be good for the market and will result in some excellent "trickle-down" technologies for the home theater user.

The D-ILA technology is based on an innovation in microchip design that packs 2048 x 1536 pixels on a single 1.3" chip (labeled a QXGA device). This makes possible display of HD images at full-spec resolution of 1920 x 1080 (with support for 1080p possible). Overall, D-ILA projectors produce higher resolutions, better contrast ratios, less image artifacts, and better tonal and color information than just about any LCD front projection device.

How it works
The light from the xenon lamp travels through a polarized beam splitter (PSB), which is reflected off the D-ILA device, then passed through the projection lens and onto the screen. High brightness and high resolution are achieved using a reflective LCOS device with a high aperture ratio (93%) and high-density pixels, providing real resolution with pixels that blend almost seamlessly together. High contrast is achieved using vertical alignment liquid crystals of normally black operation and a high-precision optical system. Analog gradation makes it possible to reproduce dark areas with high S/N (signal-to-noise ratio) because the D-ILA® device has an S-shape response. In combination with the high-speed response of the vertical alignment liquid crystal, JVC's D-ILA® technology makes it possible to reproduce smooth, noiseless motion pictures with clear, sharp high definition and film-like picture quality.

What’s Next?
JVC is currently developing the next-generation of D-ILA chips, including a new 0.7" device (1400 x 1050) which is designed to take advantage of higher yields (and lower costs) while offering the same HD resolution, and will enable to production of home theater projectors as well as business presentation models. This should create much needed competition for next-generation LCD and DLP projectors. Right now the contrast ratios on these projectors is greater than LCD, but far less than even single-chip DLP projectors. LCD technology, be it reflective or transmissive has a long way to go to gain significant ground in this one area, but its unique characteristics put it somewhat into a class of its own.

D-ILA Projection Advantages	D-ILA Projection Disadvantages
Excellent color reproduction Excellent contrast ratios High resolutions No "screen door" effect No screen burn-in issues	Fairly expensive Currently geared towards high-end and commercial uses