- Lamp Reflectors Illuminate Tiny Chips
Brent D. Johnson
As equipment companies such as JVC and Aurora migrate toward high-density 8-in.-diameter wafer sizes, chip sizes are becoming smaller and more difficult to illuminate. This creates new problems for optical designers.
The dual-paraboloid design of this lamp reflector provides 25 percent more light than elliptical reflectors and enables effective illumination of small chips. Courtesy of Wavien Inc.
Development of a 0.5-in. light engine platform by Wavien Inc. (formerly Cogent Light Technologies Inc.), Advanced Digital Optics Inc., ColorLink and Three-Five Systems demonstrates the need for a technology that delivers high-intensity light to these tiny chips.
Milton Lee, president of Advanced Digital Optics, explains that, when you reduce a chip that normally has a 1-in. diagonal to a 0.5-in. chip, it has only 25 percent of the area of the previous chip. When the larger etendue light source is coupled into a smaller etendue target, light is lost and brightness is greatly reduced.
The Wavien arc lamp reflector is a novel, highly efficient device that gets light into a very small spot. "Because of its greater collection efficiency, [it] is one of the best ways to illuminate small chips," Lee said. The lamp is self-aligning and can be changed without changing reflectors.
No brightness lost
In its dual-paraboloid system, the first parabolic reflector collects the light and collimates it into a parallel beam, and the second collects the beam and focuses it into a tapered pipe. The light pipe also acts as a homogenizer that illuminates the digital projector images more evenly and allows the coupling of high-intensity plastic optics. The result is a 1:1 image without loss of brightness.
"We've been working on the technology for three years. It is a very effective way to illuminate a small target," Lee said. "Given the same test criteria, the Wavien lamp reflector will give off as much as 25 percent more light than a standard elliptical reflector."
Because of the greater efficiency of the lamp reflector design, the light engines the companies are developing yield higher contrast and brightness than competing technologies. The engine platforms will be used in 25- and 32-in.-diagonal displays, with an expected viewing angle of 130° to 180°, and in 40-in. displays with a 120° angle. The displays will be available early this year.
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