Combination of grating lenses for color splitting and imaging

A pair of planar reflection gratings is proposed and discussed for use in a color-splitting and imaging system, such as a projection-type color-scanne r head. Red, green, and blue light reflected from a color subject are split by a color-splitting grating lens and imaged by an image-correction gratin g, consisting of three segments, onto three line sensors arranged in parall el. The phase-shift function of the image-correction grating was optimized for each color by numerical iteration with the ray-tracing method to suppre ss aberrations resulting from the wide view angle and the three different w avelengths. Gratings were designed and fabricated, and aberration suppressi on was experimentally confirmed. (C) 2001 Optical Society of America.