Abstract: An image pickup device comprises an image pickup tube provided with a striped filter which is a repetition of a plurality of stripes, and a pair of collimation forming electrodes which form a collimation, a voltage applying circuit for respectively applying predetermined voltages for forming the above collimation to the pair of collimation forming electrodes of the image pickup tube, and a correction voltage applying circuit for varying the collimation forming voltage ratio by applying a correction voltage to the pair of collimation forming electrodes, where correction voltage has a waveform such that the signal level ratios between the signals of the stripe parts of the striped filter in the color multiplexed signal obtained from the image pickup tube, are substantially constant.

Abstract: A process for preparing glass fiber-reinforced cement sheets by dewatering a slurry wherein at least one member selected from asbestos, cotton, flax, hemp, wool, or silk fibers is added to the aqueous cement-glass fiber slurry. The sheets so produced have increased bending strengths and improved peeling resistance.