| 摘要 |
PURPOSE:To manufacture an optical reading section with less adjustment and to obtain a sharp reproduced picture regardless of a bend of a blackboard by providing a nonmagnification lens array and an image sensor to a frame fitted to a blackbard freely movably in the lengthwise direction of the black board in the vicinity of the blackboard. CONSTITUTION:The nonmagnification lens array 18 with a small aperture angle with nearly equal length as a short side length of the blackboard near the blackboard and the image sensor 20 are fitted to the frame 14 fitted freely movably in the lengthwise direction of the blackboard 10 in a direction orthogo nal to the lengthwise direction of the blockboard. In forwarding or reversing a pulse motor 22, the frame 14 is moved in the arrow A or B in a prescribed speed. On the other hand, in driving the image sensor 20 synchronously with the frame, the reflected light from a prescribed position on the blackboard lighted by a fluorescent light 28 is made incident via the nonmagnification lens 18 and the image sensor 20 converts the light into an electric signal. As the aperture angle of the lens array 18 is smaller, the reproduced picture is obtained more excellently without being affected by a bend of the blackboard, and no adjustment is required and it is preferred at nearly 9 deg. practically.
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