SpatiaLight and Foreal Spectrum develop LED-powered LCoS light engine

The use of LED light sources could improve the competitiveness of Liquid Crystal on Silicon (LCoS) microdisplays in rear projection TVs and front projectors.

Two California companies have struck a deal to develop and market a LED-based light engine for 1920 x 1080p Liquid Crystal on Silicon (LCoS) microdisplays. The light engine will primarily be marketed to OEM's of rear projection televisions (RPTVs) and front projectors.

LCoS microdisplay technology is an alternative to competing 3LCD and DLP (digital light processing) technologies for projection applications (see below).

The collaborators are Novato-based SpatiaLight, Inc, a leading developer and manufacturer of ultra high-resolution LCoS microdisplays, and San Jose-based Foreal Spectrum, Inc, which speciailizes in LED illumination engines & modules.

The light engine employs SpatiaLight's T-3, 1920 x 1080p imagers and is powered by a long life, solid-state LED light source rather than the standard high-pressure mercury arc lamp. The companies believe that this LED light source is a major breakthrough for LCoS technology because it removes the "lamp lifetime" issue for television manufacturers.

Most dramatically, the new LED engine will allow for thin form factor LCoS RPTVs. A typical 60-inch television based on this new light engine will be fewer than 10 inches deep in the near future.

Other advantages of LEDs include enhanced color gamut and uniformity, reduced production and maintenance costs, compact size, and reduced weight. LEDs also feature instant on/off capability for minimal heat, longer lifetime, and improved safety.

David Hakala, SpatiaLight Chairman and Chief Executive Officer added, "LCoS optical engines using solid state illumination sources such as Foreal Spectrum's LED based design provide significant improvements in important consumer characteristics such as lifetime and reliability, size and weight, and power consumption. We believe these improvements will facilitate an increasing market share trend for projection TV in large screen sizes, reversing some of the gains made by flat panels."

Anmin Zheng, Co-Founder and CEO of Foreal Spectrum, said, "Our patent- pending designs have removed many design constraints by leveraging our thin film coating capabilities. Foreal also successfully addresses fundamental LED problems such as extraction efficiency, collection efficiency, electronic control, and heat management.

Zheng says that Foreal provides everything under one roof, from the overall design to all of the individual elements. "These include coating, optics, electronics, thermal, mechanics," he says. "We can package and integrate them transparently for the end user's application."

About LCoS
Liquid Crystal on Silicon (LCoS) is one of three main competing technologies for microdisplays used in projection applications, the others being DLP and 3LCD.

In a DLP system, the image is created by reflecting red, green and blue light from a DLP chip containing millions of tiny moveable mirrors. In 3LCD systems, light passes through three transmissive LCD microdisplays that show the image, and these different-colored images are recombined and projected onto the screen.

LCoS uses reflective LCD microdisplays, so that light is reflected back or absorbed depending on the state of each pixel of the LCD panel.

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