Diopter adjustable eyepiece used for view-finders of single-lens reflex cameras or the like

Claim 2

An eyepiece used for view finders of single-lens reflex cameras or the like comprising a first lens component of a power negative as a whole having a substantially aplanatic contour, and a second lens component of a power positive as a whole arranged on the side farther from an object than said first lens component and consisting of two lens elements each having a substantially aplanatic contour, at least one of said first lens component and second lens component being able to be moved along the optical axis to adjust the diopter.

Claim 3

An eyepiece according to claim 1 wherein said first lens component and second lens component are moved in respective directions reverse to each other.

Claim 4

An eyepiece according to claim 1 or 2 wherein said first lens component comprises a negative meniscus lens element with the concave surface directed to the object side, said second lens component comprises a positive meniscus lens element with the concave surface directed to the object side and a biconvex lens element and said eyepiece satisfies the following conditions: 0.4f.sub.T <|f.sub.1 |<1.1f.sub.T 0.1f.sub.T <f.sub.2 <0.65f.sub.T wherein the reference symbol f T represents a focal length of the entire eyepiece, the reference symbol f 1 represents a focal length of the first lens component, and the reference symbol f 2 represents a focal length of the second lens component.

Claim 5

An eyepiece according to claim 1 or 2 wherein said first lens component comprises a plano-concave lens element with the concave surface directed to the object side, said second lens component comprises a positive meniscus lens element with the concave surface directed to the objective side and a biconvex lens element and said eyepiece satisfies the following conditions: 0.4f.sub.T <|f.sub.1 |<1.1f.sub.T 0.1f.sub.T <f.sub.2 <0.65f.sub.T wherein the reference symbol f T represents a focal length of the entire eyepiece, the reference symbol f 1 represents a focal length of the first lens component, and the reference symbol f 2 represents a focal length of the second lens component.

Claim 6

An eyepiece according to claim 4 having the following numerical data: ______________________________________ r.sub.1 = ∞ d.sub.1 = 24.297 r.sub.2 = 143.1785 d.sub.2 = 7.476 n.sub.1 = 1.6968 r.sub.3 = -143.1785 d.sub.3 = 0.3738 r.sub.4 = 71.1005 d.sub.4 = 4.6725 n.sub.2 = 1.6968 r.sub.5 = 985.6041 d.sub.5 = (variable) r.sub.6 = ∞ d.sub.6 = 3.738 n.sub.3 = 1.78472 r.sub.7 = 62.7479 d.sub.7 = (variable) r.sub.8 = ∞ d.sub.8 = 104.664 n.sub.4 = 1.79952 r.sub.9 = ∞ d.sub.9 = 0.0561 r.sub.10 = ∞ d.sub.10 = 5.981 n.sub.5 = 1.8061 r.sub.11 = -48.9865 f.sub.T = 100.026 mm f.sub.1 = -79.96 mm f.sub.2 = 53.96 mm ______________________________________ Maximum Image Height=13.08 mm Diameter of Exit Pupil=15.2 mm wherein the reference symbols r 1 through r 11 represent radii of curvature on the surfaces of the respective lens elements, the reference symbols d 1 through d 10 represent thicknesses of the respective lens elements and airspaces therebetween, and the reference symbols n 1 through n 5 represent refractive indices of the respective lens elements.

Claim 7

An eyepiece according to claim 1 or 2 wherein said first lens component comprises a biconcave lens element, said second lens component comprises a plano-convex lens element and a biconvex lens element and said eyepiece satisfies the following conditions: 0.4f.sub.T <|f.sub.1 |<1.1f.sub.T 0.1f.sub.T <f.sub.2 <0.65f.sub.T wherein the reference symbol f T represents a focal length of the entire eyepiece, the reference symbol f 1 represents a focal length of the first lens component, and the reference symbol f 2 represents a focal length of the second lens component.

Claim 8

An eyepiece according to claim 6 having the following numerical data: ______________________________________ r.sub.1 = ∞ d.sub.1 = 25.0739 r.sub.2 = ∞ d.sub.2 = 2.8068 n.sub.1 = 1.51633 r.sub.3 = ∞ d.sub.3 = (variable) r.sub.4 = -89.8226 d.sub.4 = 15.3437 n.sub.2 = 1.63854 r.sub.5 = -89.8226 d.sub.5 = 0.3742 r.sub.6 = 93.7708 r.sub.7 = ∞ d.sub.6 = 3.5553 n.sub.3 = 1.717 r.sub.8 = -99.0457 d.sub.7 = (variable) n.sub.4 = 1.78472 r.sub.9 = 99.0457 d.sub.8 = 2.8068 r.sub.10 = ∞ d.sub.9 = (variable) n.sub.5 = 1.79952 r.sub.11 = ∞ d.sub.10 = 104.7865 d.sub.11 = 0.05 f.sub.T = 100.00 mm f.sub.1 = -62.718 mm f.sub.2 = 47.979 mm ______________________________________ Maximum Image Height=12.7 mm Diameter of Exit Pupil=12.7 mm wherein the reference symbols r 1 through r 11 represent radii of curvature on the surfaces of the respective lens components, the reference symbols d 1 through d 11 represent thicknesses of the respective lens components and airspaces therebetween, and the reference symbols n 1 through n 5 represent refractive indices of the respective lens components.

Claim 9

An eyepiece according to claim 1 or 2 wherein said first lens component comprises a biconcave lens element, said second lens component comprises a biconvex lens element in which the radius of curvature on the surface directed to the object side is larger than that on the surface directed to the image side and a biconvex lens element and said eyepiece satisfies the following conditions: 0.4f.sub.T <|f.sub.1 |<1.1f.sub.T 0.1f.sub.T <f.sub.2 <0.65f.sub.T wherein the reference symbol f T represents a focal length of the entire eyepiece, the reference symbol f 1 represents a focal length of the first lens component, and the reference symbol f 2 represents a focal length of the second lens component.

Claim 10

An eyepiece used for view finders of single-lens reflex cameras or the like comprising a first lens component of a power negative as a whole having a substantially aplanatic contour, and a second lens component of a power positive as a whole arranged on the side farther from an object than said first lens component and consisting of one convex lens element having a substantially aplanatic contour, at least one of said first lens component and second lens component being able to be moved along the optical axis to adjust the diopter.

Claim 11

An eyepiece used for view finders of single-lens reflex cameras or the like comprising a first lens component of a power negative as a whole having a substantially aplanatic contour, and a second lens component of a power positive as a whole arranged on the side farther from an object than said first lens component and consisting of one convex lens element having a substantially aplanatic contour, at least one of said first lens component and second lens component being able to be moved along the optical axis to adjust the diopter.

Claim 12

An eyepiece according to claim 9 wherein: said first lens component comprises a negative meniscus lens component with the convex surface thereof directed toward the object; said second lens component comprises a biconvex lens component and said eyepiece satisfies the following conditions: 1.1f.sub.T >f.sub.1 >0.6f.sub.T 0.8f.sub.T >f.sub.2 >0.4f.sub.T wherein the reference symbol f T represents a focal length of the entire eyepiece, the reference symbol f 1 represents a focal length of the first lens group, and the reference symbol f 2 represents a focal length of the second lens group.

Claim 13

An eyepiece according to claim 9 having the following numerical data: ______________________________________ r.sub.1 = ∞ (Entrance Pupil) d.sub.1 = 24.3 r.sub.2 = 61.238 d.sub.2 = 6.667 n.sub.1 = 1.5891 r.sub.3 = -66.516 d.sub.3 = (variable) r.sub.4 = -40.9661 d.sub.4 = 3.333 n.sub.2 = 1.78472 r.sub.5 = -104.693 d.sub.5 = (variable) r.sub.6 = ∞ d.sub.6 = 104.664 n.sub.3 = 1.7995 r.sub.7 = ∞ d.sub.7 = 0.184 f.sub.T = 100.02 mm f.sub.1 = -87.78 mm f.sub.2 = 55.19 mm ______________________________________ Maximum Image Height=15.8 Diameter of Exit Pupil=7 mm wherein the reference symbols r 1 through r 7 represent radii of curvature on the surfaces of the respective lens components, the reference symbols d 1 through d 7 represent thicknesses of the respective lens components and airspaces therebetween, and the reference symbols n 1 through n 3 represent refractive indices of the respective lens components.