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National Semiconductor Introduces Response Time Compensation Technology for Improved LCD Display Performance

HannStar Display Corporation Integrates National's Technology Into Its Leading-Edge LCD Televisions to Eliminate Motion Distortions

May 19, 2003

SID 2003, BALTIMORE, MD - May 19, 2003 - National Semiconductor Corporation (NYSE:NSM), the leader in analog video processing, today introduced response time compensation (RTC), a display technology that speeds up the response time of liquid crystal displays (LCDs) for improved picture quality.  HannStar Display Corporation, a leading Taiwan-based manufacturer of LCD products, is using National's panel timing controller, which utilizes RTC, in its latest 23-inch LCD television panel.

"With an LCD television, video performance can suffer when playing fast moving images because the changing liquid crystal display lags behind the electrical command to accelerate.  This results in a blurred, unsatisfactory on-screen image," said Chunfu Wang, the director of HannStar's Monitor/TV Module division. "With National Semiconductor's response time compensation technology, the LCD movement is accelerated using a command from the RTC feature of the timing controller.  The result is an amazingly clear motion video performance that HannStar's LCD television panel offers consumers."

"With the introduction of response time compensation technology, National Semiconductor is continuing to provide innovative solutions for the emerging flat-panel and high-definition television markets," said Mitchell Abbey, director of marketing for flat panel displays in National's Displays Group.  "With RTC, National is enabling the proliferation of LCDs in the television market and helping customers like HannStar stay ahead in a highly competitive business environment.  National offers a wide range of products for flat panel displays, from analog products like buffers, operational amplifiers and power management ICs, to highly customized timing controllers and column drivers."

About Response Time Compensation
Nationals response time compensation technology compensates for the delayed response time between the electrical command and the optical response that occurs in LCDs.  Using digital signal processing, RTC detects and accelerates gray-to-gray transitions in the panel.  The response time of a liquid crystal display is not constant across gray levels because of the complex interaction between the controlling electric field from the command voltage; the individual molecular orientations; the flow dynamics of the liquid crystal molecules sandwiched between two sheets of glass; and the difference between the restoring and exciting forces operating on the molecules.  The optical response can lag behind the electrical command to the pixel by several image frames, resulting in smearing and other distracting image artifacts.  

In typical computer monitor applications, the image is largely stationary so the lag goes unnoticed.  However, with fast motion video, like that in TV, DVD movies and video games, the resulting image on the LCD can be smeared, blurred, and have color and contrast distortions as a result of the slow response.  National's response time compensation prevents this performance degradation.  The RTC timing controller intercepts the incoming video stream to the display panel, compares the gray-level command with the previous command to the same pixel, and inserts an appropriate, surrogate gray level.  This new gray level is pre-determined to accelerate the gray-to-gray response time precisely to the commanded state just before the next command to the pixel arrives in the next frame.  Consequently, all the gray-to-gray transitions take place in a single image frame and the result is a moving image with detail that does not blur, smear or fade as it moves.

National Semiconductor will demonstrate its response time compensation technology and the 23-inch HannStar LCD television at the SID 2003 Symposium in Baltimore, Maryland, May 18-23 in booth 1410.

About National Semiconductor
National Semiconductor is the premier analog company driving the information age. Combining real-world analog and state-of-the-art digital technology, the company is focused on analog-based semiconductor products, which include stand-alone devices and subsystems in the areas of power management, imaging, display drivers, audio, amplifiers and data conversion. The company targets key markets such as wireless, displays, information infrastructure and a broad range of portable applications. With headquarters in Santa Clara, California, National reported sales of $1.5 billion for its most recent fiscal year. Additional company and product information is available on the World Wide Web at www.national.com