Phase difference detecting apparatus

Claim 1

A phase difference detecting apparatus for detecting a relative distance between a pair of focused images obtained from subject luminous flux passed through an objective lens to thereby judge a focusing state of said objective lens, comprising: a first light-receiving section constituted by picture elements arranged in a row so as to receive a first one of said focused images; a first signal reading-out section for transferring, in a predetermined direction, signals generated in said respective picture elements of said first light-receiving section and at the same time outputting said signals in parallel to each other through floating gates of a CCD; first signal generating means including said first light-receiving means, said first signal reading-out means, and means for converting said signals output in parallel from said first signal reading-out section into a first time series signal and outputting said first time series signal; a second light-receiving section constituted by picture elements arranged in a row to receive a second one of said focused images; a second signal reading-out section for transferring, in a predetermined direction, signals generated in said respective picture elements of said second light-receiving section and at the same time outputting said signals in parallel to each other; second signal generating means including said second light-receiving means, said second signal reading-­out means and means for converting said signals output in parallel from said second signal reading-out section into a second time series signal which have a predetermined quantity of relative movement relative to said first time series signal and outputting said second time series signal; switching-capacitor integrator means including a plurality of capacitive elements and switching elements for intermittently connecting said capacitive elements to each other, and for receiving said first and second time series signals; and control means for comparing sizes of said first and second time series signals with each other to thereby generate a control signal corresponding to a relation of size between said first and second time series signals, and controlling said switching elements on the basis of said control signal to cause said switching-­capacitor integrator means to generate an electric charge corresponding to an integrated value of an absolute value of a difference between said first and second time series signals and to cause said switching capacitor integrator means to generate, as a correlation value, an integrated value on the basis of said first and second time series signals in predetermined numbers whenever said quantity of relative movement is changed.