Speed and Brightness Verification while Switching Two-Brightness without Flicker on a Liquid Crystal Display

摘要

When two different colors are switched at high speed, it becomes impossible for a human to distinguish them, and the color resulting from the mixing of two original colors can be perceived. If color mixing by switching is used to display an image on a liquid crystal display (LCD), the colors of the image perceived and the one captured from the LCD will be different. Thus, this display method can prevent illegal photography of images on the LCD. The objective of this study is to develop a method to display a desired color by switching two colors on an LCD. However, there are cases where flickering occurs. If the LCD can increase the switching speed, flickering will decrease. Furthermore, if flickering occurs even if the switching speed increases, it is necessary to clarify the range of brightness difference that can switch two colors without flickering. In this study, we examined whether flickering was observed using three types of switching speeds and combining nine types of grayscale images. The results show that flickering is reduced by a switching speed of 144 Hz, and combining two dark or light grayscales in the range of gradation level 127 or less makes it possible to switch without flickering. This result is useful in the design of two switching colors for displaying the desired colors.