| 摘要 |
PURPOSE:To accurately read data corresponding to pits and to reduce the cost of a data reader by irradiating an optical card with a light beam from one side of the optical card, guiding its transmitted light to an observation device by an optical image formation system, and observing an image of pits on the optical card. CONSTITUTION:A light source 201' and a condenser lens 202' are provided on one side of the optical card 100 and a lens 300' for image formation and a line sensor 400 are provided on the other side. Light from the light source 201' is passed through the condenser lens 202' to illuminate the reverse surface of the optical card 100 and light transmitted through the optical card 100 reaches the line sensor 400 through the lens 300' for image formation, so that pits on the recording surface are image-formed. Consequently, the light is not passed through a half-mirror, so there is no light quantity loss and the S/N of a read signal is improved, and an accurate read is made. Further, the need for the half-mirror is eliminated, so the assembly adjustment of the optical system is facilitated and the cost is reduced. |
