Abstract: A color filter having filter elements respectively passing light of the colors red, green and blue is provided on a semiconductor image sensor which comprises a system of photosensitive elements. The filter elements are separated by grooves which eliminate the running of dye liquid during dyeing the various systems of filter elements and which hence eliminate color defects. Instead of grooves, the filter elements may also be separated by regions which have been converted into a structure which is substantially impervious to liquid. The color filters may also be used in a vidicon-type camera tube for imaging color pictures.

Abstract: A gamma correction circuit for a video signal which is simple to be integrated in a semiconductor body and which has a minimum of adjusting points in a simple adjusting procedure. The signal whose gamma is to be corrected is applied to a linear and to a non-linear amplifier circuit, a pulse having a determined amplitude being added in line blanking periods. The amplifier output signals whose black level is fixed are applied to a signal comparison circuit for the pulse amplitudes and a differential signal is fed back to the input of the non-linear amplifier circuit. The signal whose gamma is to be corrected is formed from the amplifier output signals via a potentiometer.