Measurement of MTFs for monochrome and color liquid crystal displays

摘要

We measured modulation transfer functions (MTFs) of liquid crystal displays (LCDs) by rectangular waveform analysis. This method is taking a picture of the bar pattern on the monitor surface with a digital camera, and analyzing the picture with a personal computer. The monitors used are the monochrome LCDs of lM(about 1 million of the number of pixels), 2M, 3M, and 5M, and the color LCDs of 1M, 2M, 3M. The display of 2M used IPS system and VA system. 3M and 5M of the monochrome LCDs were examined when there was a protective filter or not. Two or three displays are used for each system. In both the monochrome and the color LCDs, MTFs became high as the matrix size increased. In the monochrome LCDs, MTF in horizontal direction was higher than MTF in vertical direction. And there was no difference when a protective filter was used or not. MTFs of the color LCDs had little difference in horizontal direction and the vertical direction. MTFs of the LCDs are influenced on the form and the fill factor of a pixel, and composition of sub-pixels.