US 5,044,706 A · Optical element employing aspherical and binary grating optical surfaces

Abstract

An optical element (12) has aspherical (14) and binary grating (16) optical surfaces. In the preferred embodiment, the optical element (12) is a positive meniscus optical element made of germanium having a useful spectral bandpass in the infrared wavelength region. A telescope (100) includes a first positive meniscus optical element (102), having a convex aspherical surface (104) and a concave binary grating surface (106). A first negative meniscus optical element (107) having a concave binary grating surface (108) and a concave aspherical surface (110) is employed. Next is a positive power lens (112), followed by a second negative meniscus lens (118). In the preferred embodiment, the first negative meniscus optical element (107) and the positive power lens (112) are affixed to a common housing (124), which is removable from the telescope system. Removal of the housing (124) converts the telescope (100) system from a wide-field-of-view telescope (100) to a narrow-field-of-view telescope (40).

Claims17

Dependent claims

An optical element for reducing aberration in an optical system, said optical element having first and second surfaces, said first surface being an aspherical surface and said second surface being a diffractive surface and, wherein said second surface is a binary grating surface including a plurality of concentric rings, each ring having a series of phase level steps for approximating a Kinoform profile.

A telescope system having an optical axis comprising:

(a) a first positive meniscus optical element on said optical axis, having a first convex surface and a second concave surface, said first surface being an aspherical surface and said second surface being a binary grating surface;
(b) a first negative meniscus optical element, on said optical axis behind said first positive meniscus optical element and having first and second concave surfaces, said first surface being a binary grating surface and said second surface being an aspherical surface;
said binary grating surfaces comprising a plurality of concentric rings, each ring having a series of phase level steps for approximating a Kinoform profile;
(c) a positive power optical element, on said common optical axis behind said first negative meniscus optical element, having surfaces which are substantially spherical;
and
(d) a second negative meniscus optical element, on said optical axis behind said positive power optical element.

3 more elements

A telescope system comprising:

(a) a positive meniscus optical element, having a first convex surface and a second concave surface, said first surface being an aspherical surface and said second surface being a binary grating surface, said binary grating surface comprising a plurality of concentric rings, each ring having a series of phase level steps for approximating a Kinoform profile.
(b) a negative meniscus optical element, aligned on a common optical axis behind said positive meniscus optical element.

Dependencies are inferred from the claim text.

Optical element employing aspherical and binary grating optical surfaces

Life of this patent

Optical element employing aspherical and binary grating optical surfaces

Life of this patent

Abstract

Claims17