| 摘要 |
PURPOSE:To perform the completely electric selection of an information row, to unnecessitate the moving and rotating mechanism for a recording carrier, to miniaturize the device and to increase the operation speed by making only the light from a selected information row among the reflected lights from the recording rows of the recording carrier diffract toward a line sensor. CONSTITUTION:When a voltage is applied on the refraction member 1' for electric field of a corresponding optical diffraction element 23 by means of (n+1) pieces of switches in a voltage switching circuit 28, the respective refraction indice n0, n1 of the member 1' and an optical material 3 become n0not equal to n1. The laser light from a semiconductor laser 22 is made a parallel beam, transmits through a beam splitter 26 and is made incident on the element 23. The incident light transmits linearly through the place where the change of the refractive index n0 of the member 1' of the element 23 is absent, deflects with the refractive index corresponding to a pitch at the place where the change is present and is converged on the optical information row 31a on an optical card 30. The reflected light is read out by a line sensor 24 passing through an optical system and an optical element 27 and the information row 31a is converted to an electric signal. Consequently, mechanical drive is unnecessitated and the miniaturization and a high-speed operation of the device are attained. |
