| 摘要 |
PROBLEM TO BE SOLVED: To use red (R), green (G) and blue (B) LEDs for a light source for illuminating an original by making the illuminance of them equal to each other. SOLUTION: An optical head 29 is configured with an optical system consisting of a LED array light source 30 to emit an original face 1, of three mirrors 21, 22, 23 that lead its reflected light, and of an image forming lens 3, and with one line sensor 12 placed on an image forming face of the optical system and consisting of lots of photoelectric conversion elements, the light source 30 is formed by arranging a plurality of LED blocks 31 each consisting of arrangement of LEDs whose wavelength bands differ like G-R-B-G on a printed circuit board nearly in a line and emits the original face 1 and the components of the light source are lighted in a prescribed sequence for each prescribed time. Synchronously with the lighting of each light source component, lots of photoelectric conversion elements of the line sensor 12 are scanned circulatingly for the period, and information of the original face 1 is read electric signals divided by each wavelength of a plurality of the light source components and arranged in time series. Thus, the illuminance of the three colors is made bright equally by having only to increase one G LED, image data are made stable, the reader is made small in size, and the performance is considerably improved regardless of its low cost. |
