Color balancing filters using liquid crystal for image pickup

In order to correct the color deviation due to variation of illumination in film shooting, a liquid-crystal filter with dichroic dyes that can control the color temperature of the transmitted light in real time has been devel oped. By using Planck's radiation rule and the Lambert-Beer law, the absorp tion spectra of the dyes are designed. It is found that the color balance c an be adjusted continuously between 4450 and 2530 K. The time needed for co ntrol is about 80 ms. When a liquid-crystal filter is used for actual telev ision film shooting, it is confirmed that the color balance of the image ca n be corrected naturally. The present device is useful in location film sho oting for television when the color temperature of the image changes drasti cally under such conditions as the fighting changing from indoor fight to s olar light. (C) 2001 Scripta Technica.