Wide-angle eyepiece optical system employing refractive and diffractive optical elements
First Claim
1. A wide angle optical eyepiece system, which comprises a plurality of lens elements which define first, second and third groups of surfaces, all but at least one of said surfaces of said groups being refracting and said at least one surface being diffracting, said groups of surfaces being disposed along an optical axis, a surface of said first group being a front surface of said system which faces a location for the eye of the observer which is the exit pupil of said system and is spaced therefrom by an eye relief, a surface of said third group being a back surface of said system which is spaced from image plane by a back focal length, and said diffractive surface having sufficient power and refractive surfaces having sufficient curvature to provide said eye relief which is at least 80% of the focal length of said system and corrections of aberration, including spherical aberration at said exit pupil over a field angle of at least about 70°
- at said exit pupil.
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Accused Products
Abstract
Eyepiece optical systems having arrangements of surfaces where light is refracted or diffracted provide eyepieces with fewer elements and more compact designs than comparable, conventional eyepiece designs. These eyepiece optical systems have three elements each with positive focussing power, and provide a wide field-of-view of about 70° and an eye relief of approximately 80% of the total focal length of the eyepiece. One embodiment has (from the eye side) a refracting, meniscus, positive element with a surface concave toward the eye, a bi-convex element having a refracting convex surface and a second refracting convex surface, and a refractive/diffractive doublet element with a refracting convex surface and diffracting surface (each element being of positive power). Another embodiment, from the eye side has a first diffractive/refractive doublet having a diffracting surface and a convex refracting surface, an equi-convex element having two refracting convex surfaces and a second refracting/diffracting element having a diffracting surface and a convex refracting surface.
75 Citations
15 Claims
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1. A wide angle optical eyepiece system, which comprises a plurality of lens elements which define first, second and third groups of surfaces, all but at least one of said surfaces of said groups being refracting and said at least one surface being diffracting, said groups of surfaces being disposed along an optical axis, a surface of said first group being a front surface of said system which faces a location for the eye of the observer which is the exit pupil of said system and is spaced therefrom by an eye relief, a surface of said third group being a back surface of said system which is spaced from image plane by a back focal length, and said diffractive surface having sufficient power and refractive surfaces having sufficient curvature to provide said eye relief which is at least 80% of the focal length of said system and corrections of aberration, including spherical aberration at said exit pupil over a field angle of at least about 70°
- at said exit pupil.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
Specification