Real-image zoom finder with rotationally asymmetric surface
First Claim
1. A real-image finder comprising, in order from an object side thereof:
- an objective optical system having a positive refracting power;
an image-inverting optical system having a reflecting surface, said image-inverting optical system erecting an intermediate image formed by said objective optical system; and
an ocular optical system having a positive refracting power;
wherein said objective optical system includes, in order from an object side thereof, a first lens unit having a negative refracting power, a second lens unit having a positive refracting power, and a third lens unit having one of a positive refracting power and a negative refracting power,wherein when zooming from a wide-angle end to a telephoto end is performed, a spacing between each pair of lens units among said first, second and third lens units is changed, andwherein said reflecting surface of said image-inverting optical system is arranged in a form of a curved reflecting mirror having an optical power and having a rotationally asymmetric surface configuration that corrects decentration aberrations produced by said curved reflecting mirror.
1 Assignment
0 Petitions
Accused Products
Abstract
A high-performance real-image finder with a zoom objective optical system wherein a power is given to a reflecting surface of an image-inverting optical system to reduce the size in the direction of the thickness, and at the same time, a rotationally asymmetric surface is used in the image-inverting optical system to correct rotationally asymmetric decentration aberrations. The zoom objective optical system Ob has a first lens unit G1 of negative power, a second lens unit G2 of positive power, and a third lens unit G3 of positive or negative power. The real-image finder further includes an image-inverting optical system PP for erecting an intermediate image formed by the objective optical system Ob, and an ocular optical system Oc having a positive refracting power. At least one of reflecting surfaces S8 and S9 of the image-inverting optical system PP is a curved reflecting mirror having an optical power and has a rotationally asymmetric surface configuration that corrects decentration aberrations produced by the curved reflecting mirror.
-
Citations
23 Claims
-
1. A real-image finder comprising, in order from an object side thereof:
-
an objective optical system having a positive refracting power; an image-inverting optical system having a reflecting surface, said image-inverting optical system erecting an intermediate image formed by said objective optical system; and an ocular optical system having a positive refracting power; wherein said objective optical system includes, in order from an object side thereof, a first lens unit having a negative refracting power, a second lens unit having a positive refracting power, and a third lens unit having one of a positive refracting power and a negative refracting power, wherein when zooming from a wide-angle end to a telephoto end is performed, a spacing between each pair of lens units among said first, second and third lens units is changed, and wherein said reflecting surface of said image-inverting optical system is arranged in a form of a curved reflecting mirror having an optical power and having a rotationally asymmetric surface configuration that corrects decentration aberrations produced by said curved reflecting mirror. - View Dependent Claims (2, 3, 4, 5, 6, 7, 21, 22, 23)
-
-
8. A real-image finder comprising, in order from an object side thereof:
-
an objective optical system having a positive refracting power; an image-inverting optical system having a reflecting surface, said image inverting-optical system erecting an intermediate image formed by said objective optical system; and an ocular optical system having a positive refracting power; wherein said objective optical system includes, in order from an object side thereof, a first lens unit having a negative refracting power, a second lens unit having a positive refracting power, and a third lens unit having a negative refracting power, wherein zooming is performed by changing a spacing between each pair of lens units among said first, second and third lens units, and wherein said reflecting surface of said image-inverting optical system has an optical power, and at least one surface of said image-inverting optical system has a rotationally asymmetric surface configuration. - View Dependent Claims (9, 10, 11, 12)
-
-
13. A real-image finder comprising, in order from an object side thereof:
-
an objective optical system having a positive refracting power; an image-inverting optical system having a reflecting surface, said image-inverting optical system erecting an intermediate image formed by said objective optical system; and an ocular optical system having a positive refracting power; wherein said objective optical system includes, in order from an object side thereof, a first lens unit having a negative refracting power, a second lens unit having a positive refracting power, and a third lens unit having a positive refracting power, wherein zooming is performed by changing a spacing between each pair of lens units among said first, second and third lens units, and wherein said reflecting surface of said image-inverting optical system has an optical power, and at least one surface of said image-inverting optical system has a rotationally asymmetric surface configuration. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
-
Specification