Ophthalmic apparatus
AssigneeNikon Corporation
InventorYasunori Ueno
Life of this patent
Estimating the term…
Abstract
An ophthalmic apparatus having a smaller size while guaranteeing a required optical performance from each optical system component is provided. The ophthalmic apparatus includes a fogging optical system for removing an accommodation power of an eye being examined so that the eye is properly relaxed. A detecting optical system is used for detecting information relating to the eye being examined. The fogging optical system and the detecting optical system share a common lens group containing at least one cemented lens. Positive and negative lenses are included in the cemented lens. The common lens group, as a whole, has a positive refractive power.
Claims5
An ophthalmic apparatus, comprising:
- a fogging optical system for eliminating an accommodation power of an eye being examined so as to realize relaxation;
- a detecting optical system for detecting information relating to the eye being examined;
- and
- at least one cemented lens, including a positive lens and a negative lens, which, as a whole, has a positive refractive power, said at least one cemented lens forming at least part of a common lens group shared by said fogging optical system and said detecting optical system,
- satisfying the following conditions:
- 0<(r2+r1)/(r2-r1)<0.2;
- 0.05<1n1-n2<0.25;
- 15<.sigma.1-.sigma.2<30
- wherein r1 is a radius of curvature of a surface of said positive lens other than the cemented surface, r2 is a radius of curvature of a surface of said negative lens, other than the cemented surface, n1 is a refractive index of said positive lens with respect to the d-line, n2 is a refractive index of said negative lens with respect to the d-line, .sigma.1 is Abbe number if said positive lens, and .sigma.2 is Abbe number of said negative lens.
Dependencies are inferred from the claim text.