Focus detecting apparatus

Claim 2

A focus detecting apparatus according to Claim 1, wherein said pupil dividing means has two sets of stop openings of which one pair of openings symmetrical with respect to said main optic axis are of the same shape and differ in at least size from the other pair of openings symmetrical with respect to said main optic axis, and is designed such that straight lines passing through the centers of said pairs of stop openings symmetrical with respect to said main optic axis are orthogonal to each other and the radius of a circumcircle tangent to said pair of larger openings about said main optic axis is greater than the radius of a circumcircle tangent to said pair of smaller openings.

Claim 3

A focus detecting apparatus according to Claim 2, wherein said two sets of four stop openings are formed into substantially elliptical shapes whose minor axes are along said straight line passing through the centers of said pair of stop openings symmetrical with respect to said main optic axis.

Claim 4

A focus detecting apparatus according to Claim 2, wherein said two sets of re-imaging lenses corresponding to said two sets of stop openings symmetrical with respect to said main optic axis are eccentric by a predetermined amount in a direction away from said main optic axis relative to the centers of respective ones of said stop openings, and said re-imaging lenses corresponding to said smaller stop openings are designed to have a smaller lens thickness than said re-imaging lenses corresponding to said larger stop openings.

Claim 5

A focus detecting apparatus according to Claim 2, wherein said photoelectric detecting means includes two sets of line sensors orthogonal to each other for receiving two sets of secondary images formed by said two sets of re-imaging lenses corresponding to said two sets of stop openings, and the line sensors corresponding to the secondary images by the light beams passing through the larger stop openings are greater in the length of the area on the corresponding primary image plane, i.e, the so-called distance measuring area, than the line sensors corresponding to the secondary images by the light beams passing through the smaller stop openings.

Claim 6

A focus detecting apparatus for photo-electrically detecting a plurality of object images formed by light beams from the same object passing through marginal areas on an exit pupil plane symmetrical with respect to a main optic axis passing through the center of the exit pupil of an objective lens to thereby effect focus detection, including: a condenser lens provided near the image plane of a primary image formed through said objective lens; a first focus detecting optical system provided with first pupil dividing means provided on a plane conjugate with the exit pupil of said objective lens with respect to said condenser lens and including a pair of stop openings for optically dividing the marginal area of said exit pupil into two divided pupil areas of equal shape symmetrical with respect to said main optic axis, and a pair of first re-imaging lenses provided at positions rearward of said pair of stop openings and symmetrical with respect to said main optic axis and corresponding to said stop openings; a second focus detecting optical system provided with second pupil dividing means provided on a plane conjugate with the exit pupil of said objective lens with respect to said condenser lens and including a pair of other stop openings for optically dividing the marginal area of said exit pupil differing from the divided pupil areas by said first pupil dividing means symmetrical with respect to said optic axis into two divided areas equal in shape to each other and of a size differing from the size of the divided pupil areas by said first pupil dividing means and formed so that the interval between the centers of light beams passing through said two divided pupil areas may be substantially equal to the interval between the centers of light beams passing through said two divided pupil areas by said first pupil dividing means and moreover a circumcircle tangent to said two divided pupil areas may have a radius differing from the radius of a circumcircle tangent to said two divided pupil areas by said first pupil dividing means, and a pair of re-imaging lenses provided at positions rearward of said pair of stop openings in said second pupil dividing means and corresponding to respective ones of said stop openings for forming the secondary images of the object; and photoelectric detecting means for receiving a plurality of sets of said secondary images formed by said re-imaging lenses of said first and second focus detecting optical systems and detecting the deviation between the relative positions of each of said sets of secondary images.

Claim 7

A focus detecting apparatus according to Claim 6, wherein said pair of stop openings in said first pupil dividing means are larger than said pair of stop openings in said second pupil dividing means, a straight line passing through the centers of said pair of stop openings in said first pupil dividing means and a straight line passing through the centers of said pair of stop openings in said second pupil dividing means are orthogonal to each other, and the radius of a circumcircle tangent to said pair of larger stop openings about said main optic axis is larger than the radius of a circumcircle tangent to said pair of smaller stop openings

Claim 8

A focus detecting apparatus according to Claim 7, wherein said two sets of four stop openings are formed into substantially elliptical shapes whose minor axes are along said straight line passing through the centers of said pair of stop openings symmetrical with respect to said main optic axis.

Claim 9

A focus detecting apparatus according to Claim 7, wherein said first re-imaging lenses and said second re-imaging lenses corresponding to said two sets of stop openings, respectively, symmetrical with respect to said main optic axis are eccentric by a predetermined amount in a direction away from said main optic axis relative to the centers of the respective stop openings and said second re-imaging lenses corresponding to said smaller stop openings in said second pupil dividing means are designed to have a smaller lens thickness than said first re-imaging lenses corresponding to said larger stop openings in said first pupil dividing means.

Claim 10

A focus detecting apparatus according to Claim 7, wherein said photoelectric detecting means includes two sets of line sensors orthogonal to each other for receiving two sets of secondary images formed by said first re-imaging lenses and said second re-imaging lenses, respectively, corresponding to said two sets of stop openings, and the line sensors corresponding to the secondary images by light beams passing through said larger stop openings are greater in the length of the area on the corresponding primary image plane, i.e., the so-called distance measuring area, than the line sensors corresponding to the secodary images by light beams passing through said smaller stop openings.

Claim 11

A focus detecting apparatus according to Claim 1, wherein said condenser lens and said re-imaging lenses are aspherical lenses and are designed in accordance with the data given in Table 1.

Claim 12

A focus detecting apparatus according to Claim 1, wherein said condenser lens and said re-imaging lenses are aspherical lenses and are designed in accordance with the data given in Table 2.

Claim 13

A focus detecting apparatus comprising: a first optical system including a first pair of stop openings separated in a first direction transverse to the optical path, the first system being arranged to produce a first pair of secondary images; a second optical system including a second pair of stop openings which are larger than the openings of the first pair and which are separated in a second direction transverse to the optical path, the second system being arranged to produce a second pair of secondary images, and the centers of the second openings being separated by a distance substantially equal to the separation between the centers of the first openings; and photoelectric detecting means for receiving the secondary images to enable detection of a defocus amount on the basis of the relative positions of at least a pair of said secondary images.