Advanced Imaging


Advanced Imaging Magazine

Updated: July 8th, 2008 05:26 PM CDT

Understanding the Display Selection Challenge

Selecting Displays
NEC Electronics America
One solution to stable grayscale characteristics, regardless of viewing angle, and an accelerated response time between intermediate grayscales (important in medical imaging) is the super-fine thin-film transistor (SFT) technology offered by NEC Electronics America. SFT induces liquid crystal molecules to line up evenly and rotate horizontally when electrically charged. The rotation angle of the liquid crystal molecules changes according to the amount of electrical voltage applied and affects the amount of light that is transmitted. The liquid crystal molecules are always horizontal, so they appear the same size from the front. Therefore, even if the viewing angle changes, there is very little brightness or color deviation.
NEC Electronics America

By Robert Dunhouse and Cathy Dotson, NEC Electronics America, Inc.

A key parameter for advanced diagnostics is the stability of color when viewed from any angle, where even the slightest deviation can affect the perception of the medical professional and possibly affect accurate diagnosis. There are several technologies that have addressed wide viewing angles but at the expense of color stability. And, since medical applications deal with patient well-being, LCDs must demonstrate a high level of reliability, meet stringent quality standards with no pixel defects and maximum available up time (24/7), and support long product life cycles.


A variety of factors play important roles in these markets. In factory automation applications, the physical environment of the display is often unpredictable. At times, harsher environments require more rugged panel structure with enhanced specifications addressing shock, vibration, temperature and humidity. Due to long product life cycles, it is often critical to have long-term support for the production of the panel, as well as a generous (1 to 2 years) phase-out notice and a last-time-buy opportunity for customers. Another factor that has become increasingly important is image quality in diverse lighting environments (indoor and outdoor). Consequently, this market requires a display that readily adapts to varying light conditions. The easiest way to answer this question is by selecting a display that operates well in any ambient light environment and under a range of operating conditions.


Display needs are becoming increasingly diversified with the proliferation of new applications for LCDs. Fully understanding which needs are critical to the specific market, as well as the right questions to ask about display functionality, are essential to selecting the right display panel for a given application. By identifying the critical requirements for their application and using a prepared set of questions or criteria during the vetting process, engineers can avoid costly mistakes and select the panel that best meets their needs.

About the Authors

Robert Dunhouse is the engineering manager and Cathy Dotson is the senior product marketing engineer for the Displays Strategic Business Unit, NEC Electronics America, Inc. NEC Electronics America (Santa Clara, Calif.) is a developer, manufacturer and supplier of semiconductor-based advanced technology solutions, system solutions and platform solutions.

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