| Summary: | 碩士 === 國立雲林科技大學 === 工業設計系碩士班 === 90 === This study aimed to investigate the visibility of elderly people of text/ background color combination on the TFT-LCD. Two experiments were adopted to find difference threshold of elderly people and young people (50 percent of subjects were able to see Chinese characters). The characters used were Thin Ming font with 16pt and the viewing distance was 50 cm in this experiment. Fourteen background colors were chosen by HSB color system. In the first experiment, the numeric of H (Hue) and S (Saturation) was 0. Only numeric of B (Brightness) was changed. In the second experiment, the numeric of S and B was 100. Only numeric of H was changed. The numeric of background color minus the numeric of character color was the variation the HSB color system. Using the interpolation, it was able to get difference threshold of two groups of subjects. Besides, by calculating the variation with CIEL*a*b* color formula, it was able to get the numeric of △L*ab, △C*ab, △H*ab, △E*ab and ratio of luminance contrast on CIEL*a*b* color system. According to the results of this study:
1.Significant correlation existed between age and brightness variation amount or Hue’s variation amount on HSB color system. When Elderly people wanted to reach difference threshold, they needed more variation amount than younger people.
2.The Monitor（TFT-LCD / CRT）influenced color on HSB color system.
3.Significant correlation existed between percentage of subjects who were able to see characters and brightness variation amount or Hue’s variation amount on HSB color system, or △E*ab on CIEL*a*b* color system. With larger brightness variation amount, Hue’s variation amount and numeric of △E*ab, the better the visibility of subjects.
4.In the first experiment, in order to reach difference threshold with HSB = 0,0,0 (background color) by elderly people, brightness variation amount was lager than that in HSB = 0,0,100. In the second experiment, in order to reach difference threshold with HSB=90,100,100 by elderly people, Hue’s variation amount was the largest among 12 background color.
5.With CIEL*a*b* color system, in order to reach difference threshold with HSB=120,100,100 by elderly people, the numeric of △E*ab was the largest among fourteen background colors. In order to reach difference threshold with HSB=180,100,100 by elderly people, the ratio of luminance contrast was the largest among fourteen background colors.
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