| 摘要 |
PROBLEM TO BE SOLVED: To enable an optical reading device to read a dot pattern even when inclined to an information input auxiliary sheet, and to provide an information input auxiliary sheet capable of absorbing or attenuating reflection light of unnecessary infrared rays, excluding a reflection pattern of infrared rays, or changing a wavelength region.SOLUTION: The optical reading device includes infrared ray irradiation means for irradiating infrared rays of a predetermined wavelength region, a filter for transmitting infrared rays of at least the predetermined wavelength region and shielding visible light, imaging means for imaging the infrared rays of at least the predetermined wavelength region, and decoding means for decoding a dot pattern image imaged by the imaging means to a dot code. Dots of a dot pattern are printed on a transparent sheet in ink having an infrared diffuse characteristic at least in the prescribed wavelength region or the infrared diffuse reflection characteristic and a visible light transmission characteristic. |
