Endoscope with high frequency accessory and reduced video interference

Claim 1

An endoscope comprising: an elongate insertion member insertable within a body cavity; an image-forming optical system disposed at a tip of said insertion member, said image-forming optical system for forming an image of an object under observation on a focal plane thereof; illuminating means for illuminating an object to be imaged within an image-forming range of said image-forming optical system; a solid state optical image pickup having a plurality of photo-electrically converting receiver elements each arranged on a pickup plane coinciding with said focal plane of said image forming optical system, said solid state optical image pickup producing picture element signals corresponding to an image formed thereon; driving circuit means connected with said solid state optical image pickup, said driving circuit means for applying clock signals to said solid state optical image pickup in order to read out said picture element signals during a reading period; frame memory means connected with said solid state optical image pickup, said frame memory means for storing read out picture element signals; television signal converter means connected with said frame memory means for reading out said picture element signals written in said frame memory means and for converting said read out picture element signals into video signals of a predetermined television signal format; display means connected with said television signal converter means, said display means for displaying said video signals as a television picture on a display monitor; accessory means for being locatable through said insertion member; high frequency oscillation means for driving said accessory means, said high frequency oscillation means for producing high frequency components within a band when said pickup element signals are read out of said solid state optical image pickup; gate means connected to said driving circuit means, said gate means for gating clock signals of said driving circuit means during a read out period of said solid state optical image pickup; and control gate generator means for supplying high and low levels of control gate signals in repeated synchronization with a pickup function of said solid state optical image pickup, said control gate generator means being connected to said gate means and said high frequency oscillation means in order to inhibit an operation of said accessory means only during said reading period; wherein said reading period is of shorter duration than each video frame period of said predetermined television signal format.