Evaluation of the Samsung 240T Analog and Digital, 24-Inch Diagonal 1920 x 1200 Pixel LCD Color Monitor

摘要

The Samsung 240T, 24 inch, 1920 x 1200 pixel LCD color monitor ($5511) is the first LCD that has the capability for both digital and analog addressing at the full 1920 x 1200 addressability. NIDL reports here results on extensive digital and analog testing. We found that digital addressing improves the sharpness of visually observed SMPTE test patterns, of measured profiles of a single pixel wide line, and of Briggs patterns. This improvement is achieved in part by eliminating a spurious extra part of a pixel (phantom) observed in analog mode. We achieved 1920 x 1200 digital addressing by using an Elsa Synergy III graphics card in the single head mode with a single DVI channel by decreasing the vertical refresh rate to 52 Hz. Images look excellent with no flicker at this lower refresh rate. At 1920 x 1200 digital addressability, Briggs scores are 16, 38, 59 and 71 for the Delta-i, Delta-3, Delta-7 and Delta- 15 contrast ratio targets, compared to 12, 34, 55 and 58 in the analog mode. The constancy of illumination in an LCD display allows the vertical refresh rate to be reduced to 52 Hz without observable flicker; the geometrical arrangement of the backlight, however, can lead to a somewhat higher luminance non-uniformity (23.4% versus 20% WC requirement for CRT monitors). Luminance rise time in digital mode averages 13 ms compared to 20 ms in analog mode. The Samsung 240T LCD easily surpassed the WC specifications for luminance, contrast ratio, halation, CCT, reflectance, tonal transfer curve, uniformity of chromaticity, pixel aspect ratio, contrast modulation, jitter/swim/drift, and warm-up time. NIDL rates the 240T a 'B' in a monoscopic mode and therefore certifies it as an acceptable color monitor in a dual head WC workstation. Also, it could be used as the main task monitor for a non-stereo mode color workstation, as is utilized at NAVO WSC. It cannot replace a CRT where a stereoscopic-mode capable color monitor is required.