| 摘要 |
PURPOSE:To attain simple correcting of the shading by disposing a light- transmission-controlling liquid crystal plate in the optical pass in which a pattern to control the transmission is generated between the original reading position and an image sensor, and by supplying to said plate a control signal to control the generation-location of said pattern. CONSTITUTION:When the operator sets a numerical value of desired stage by means of a BCD switch 201, a correspondent signal is outputted from the switch 201. The signal is decoded by a decoder 202, reaches an electrode-line selecting part 203, and selects a correspondent one among electrode lines 107. A drive pulse outputted from a drive pulse generating circuit 204 is so supplied to the selected one of the electrode lines 107 and all ones 108 that the voltage is phase reversed. The display pattern of a liquid crystal display 100 shows as a black dot at a location correspondent to the position at a distance nearest the electrode lines 107 and 108. In such a way as the above, the shading due to the characteristic of the quantity of light the fluorescent lamp is corrected.
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