초록 ▼

Light intensity distributions of object images whose relative positions vary with a focusing state of an objective lens are formed by a lens assembly based on light fluxes transmitted through the objective lens, and the distributions are sensed by sensing devices having a plurality of photo-sensors

Light intensity distributions of object images whose relative positions vary with a focusing state of an objective lens are formed by a lens assembly based on light fluxes transmitted through the objective lens, and the distributions are sensed by sensing devices having a plurality of photo-sensors to produce first and second signals for the respective light intensity distributions. The first and second signals are processed by relatively displacing the first and second signals under a first relationship and by relatively displacing the first and second signals under a second relationship different from the first relationship to determine a relative positional relationship of the light intensity distributions. If there is identical or essentially identical portion is found in the processing of the first signal and the second signal, the previous processing result is utilized to shorten the processing time.

대표청구항 ▼

An apparatus for detecting a focusing state of an objective lens comprising: optical means for receiving light fluxes transmitted through an objective lens and forming light intensity distributions based on an object whose relative position varies with a focusing state of the objective lens, sense m

An apparatus for detecting a focusing state of an objective lens comprising: optical means for receiving light fluxes transmitted through an objective lens and forming light intensity distributions based on an object whose relative position varies with a focusing state of the objective lens, sense means having a plurality of photo-sensors for sensing the light intensity distributions to produce first and second signals for the respective light intensity distributions; and processing means for manipulating the first and second signals to sequentially and relatively displace the first and second signals under a first relationship to determine a first correlation amount V1(k), manipulating the first and second signals to sequentially and relatively displace the first and second signals under a second relationship to determine a second correlation amount V2(k), subtracting the second correlation amount from the first correlation amount to determine an evaluation amount V(k), calculating the evaluation amount for each relative displacement, and calculating the relative position of the light intensity distributions based on the evaluation amounts to produce a signal indicating the focusing state of the objective lens; said processing means calculating one of the first and second correlation amounts by utilizing another correlation amount previously calculated for another relative displacement.