Abstract This invention provides a reflecting-refracting, i.e. catadioptric, telephoto lens of F/7 and having an angle of field of 5*. The lens system comprises a positive meniscus lens having a convex surface directing toward an object, a main reflecting mirror of concave back surface having a refracting surface and a reflecting surface, an additional mirror of convex back surface placed near to said positive meniscus and having a refracting surface and a reflecting surface, and a concave lens cemented to said reflecting mirror through a positive lens placed therebetween and having a concave surface directing toward the object. The central portion of the main reflecting mirror is not reflecting; it allows the passage of light. The composite focal length of the negative lens, positive lens and the main mirror is negative when the light rays pass therethrough and the assembled length of the system is less than 1/3.5 of the focal length of the whole system.
A catadioptric telephoto objective system lens comprising, viewing from the advance of the light, a positive meniscus lens (L1) having a convex surface directed toward an object, a main reflecting mirror (M1) having a central portion to allow the passage of light, said mirror having a light refracting surface concave toward an object and a concave light reflecting back surface of longer radius than said concave refracting surface, a second mirror (M2) having a smaller diameter than the diameter of thE main reflecting mirror and the diameter of the positive meniscus lens (L1), said second mirror (M2) being adjacent the positive meniscus lens (L1) and having a convex light refracting surface facing the main reflecting mirror and a convex light reflecting back surface of longer radius than said convex refracting surface, and a negative lens (L2) cemented to a positive lens (L3) which in turn is in contact with the central portion of the concave light refracting surface of the main reflecting mirror (M1), the negative lens (L2) having a concave surface directed toward an object, the composite focal length of the lenses (L2), (L3) and the mirror (M1) being negative when the light rays pass therethrough and the assembled length of the optical system being less than 1/3.5 of the focal length of the whole system.
Claim 2
Dependent Claim
217 words
A catadioptric telephoto objective system lens comprising, viewing from the advance of the light, a positive meniscus lens (L1) having a convex surface directed toward an object, a main reflecting mirror (M1) having a central portion to allow the passage of light, said mirror having a light refracting surface concave toward an object and a concave light reflecting back surface of longer radius than said concave refracting surface, a second mirror (M2) having a smaller diameter than the diameter of thE main reflecting mirror and the diameter of the positive meniscus lens (L1), said second mirror (M2) being adjacent the positive meniscus lens (L1) and having a convex light refracting surface facing the main reflecting mirror and a convex light reflecting back surface of longer radius than said convex refracting surface, and a negative lens (L2) cemented to a positive lens (L3) which in turn is in contact with the central portion of the concave light refracting surface of the main reflecting mirror (M1), the negative lens (L2) having a concave surface directed toward an object, the composite focal length of the lenses (L2), (L3) and the mirror (M1) being negative when the light rays pass therethrough and the assembled length of the optical system being less than 1/3.5 of the focal length of the whole system.
Claim 3
Dependent Claim
25 words
A catadioptric objective system lens according to claim 1, wherein the elements of the system referred to in claim 1 have the following numerical values:
Claim 4
Dependent Claim
25 words
A catadioptric objective system lens according to claim 1, wherein the elements of the system referred to in claim 1 have the following numerical values: