Focus detection device and image-capturing apparatus

Abstract

A focus detection device includes: a sensor outputting a pair of focus detection signal sequences, each of which being made of a plurality of focus detection signals; a difference calculation unit obtaining a plurality of differences by sequentially calculating differences between focus detection signals corresponding to each other in the pair of focus detection signal sequences; a division unit dividing the pair of focus detection signal sequences into at least two pairs of partial signal sequences based on the plurality of differences; a focus detection parameter calculation unit calculating a first focus detection parameter according to a phase difference amount of a first pair of partial signal sequences and a second focus detection parameter in accordance with a phase difference amount of a second pair of partial signal sequences; and a focus adjustment parameter determination unit determining either the first or second focus detection parameters, as a focus adjustment parameter.

1 . A focus detection device comprising:
 an image sensor that includes a plurality of first light receiving units each receiving light which has passed through a first region of a photographing optical system forming a subject image and a plurality of second light receiving units each receiving light which has passed through a second region of the photographing optical system and that outputs a set of first signals generated at the plurality of first light receiving units and a set of second signals generated at the plurality of second light receiving units; and   a controller that divides each set of the set of first signals and the set of second signals into a plurality of sections and controls drive of the photographing optical system based upon a shift amount of the set of first signals and the set of second signals respectively corresponding to a section among the plurality of sections.   
     
     
         2 . The focus detection device according to  claim 1 , wherein
 the controller divides the each set of the set of first signals and the set of second signals into the plurality of sections, calculates the shift amount of the set of first signals and the set of second signals respectively corresponding to each of the plurality of sections and controls the drive of the photographing optical system based upon the shift amount calculated.   
     
     
         3 . The focus detection device according to  claim 1 , wherein
 the set of first signals is based upon the subject image formed by the light which has passed through the first region of the photographing optical system, and   the set of second signals is based upon the subject image formed by the light which has passed through the second region of the photographing optical system.   
     
     
         4 . The focus detection device according to  claim 1 , wherein
 the image sensor includes a plurality of pixels each having a lens, and   the plurality of pixels respectively have the plurality of first light receiving units each arranged at a first position corresponding to the lens and respectively have the plurality of second light receiving units each arranged at a second position different from the first position corresponding to the lens.   
     
     
         5 . The focus detection device according to  claim 1 , wherein
 the controller divides the each set of the set of first signals and the set of second signals based upon an absolute value of a difference between each signal of the set of first signals and each signal of the set of second signals.   
     
     
         6 . The focus detection device according to  claim 1 , wherein
 the set of first signals is based upon the subject image formed by the light which has passed through the first region,   the set of second signals is based upon the subject image formed by the light which has passed through the second region, and   the controller divides the each set of the set of first signals and the set of second signals into a section in which an absolute value of a difference between each signal of the set of first signals and each signal of the set of second signals is equal to or higher than an average value of differences constituted with the difference and a section in which the absolute value is lower than the average value.   
     
     
         7 . The focus detection device according to  claim 1 , wherein
 the controller controls the drive of the photographing optical system based upon the shift amount calculated in correspondence with an image of a subject located in closest distance from the photographing optical system upon calculating shift amounts constituted with the shift amount.   
     
     
         8 . An image-capturing apparatus comprising:
 the focus detection device according to  claim 1 .