Method of manufacturing target of image pickup tube

A method of manufacturing a target of an image pickup tube comprising the steps of:

• (a) forming a plurality of groups of transparent conductive signal electrodes on a transparent insulating base plate including the image area thereof,
• (b) forming a protective layer on substantially said image area of said base plate,
• said protective layer being substantially unsoluble in an etching liquid by which a portion of an insulating layer constituting an intermediate layer of insulation may be etched away,
• (c) forming said insulating layer constituting said intermediate layer of insulation on the protective layer and on at least the portion of the signal electrodes serving as connection part between the signal electrodes and a location at which bus bars are to be applied, said layer being selectively removed from said image area by the etching liquid,
• (d) removing said protective layer,
• (e) mounting bus bars each electrically connected to corresponding transparent conductive signal electrodes via said connecting part and insulated from the remaining transparent conductive signal electrodes by an interposed intermediate isolation layer formed in said step (c), and
• (f) forming a photoconductive layer on at least a plurality of groups of transparent conductive signal electrodes in said image area.