Honeywell G.m.b.h.

United States of America As Represented by the Secretary of the Air Force

Irving R Abel

Marcus R Hatch

James W Howard

Bruce R Reynolds

Apparatus for continuously determining the position of best focus of an objective lens and a system having a video output. The technique uses a transmissive plate of variable thickness located on one side of the field stop of the optical system associated with the video output. The plate covers the full vertical field of the system and covers on the order of 30 to 40 resolution elements in the horizontal direction. The plate is divided vertically into platelets of different thicknesses which are distributed in such a way as not only to cover the range of defocus of the system, but to discriminate against possible variations in scene content. The plate is placed outside the active area which will be displayed by the video; therefore the variations in thickness and in focus introduced by the plate are not displayed on the video, but are only used for the purpose of continuously determining the position of best focus. A spherical shell of zero power may be placed between the objective lens and the field stop in order to create a bias so that focal shifts introduced by the plate may be distributed about a nominal position, rather than all in a positive direction.

Autofocus system for infrared imaging device

Wide field of view correction for wide spectral band imaging systems is achieved in reflective versions of the Schmidt and Schmidt-Cassegrain systems by the use of a fold mirror which also serves as a corrector plate. A method for fabricating the corrector plate is described.

Reflective Schmidt system with nonrotationally symmetric corrector

An improved optical system for thermal imaging systems using wide field of view optics in conjunction with large detector arrays in which a detector cold shield, system aperture stop and scanning subassembly are placed in substantially the same location such that the size of the scanning optics is minimized and cold shielding efficiency is maximized.

Optical detection system having a detector lens comprising a rear

An optical system produces sensor data from at least two fields of view (which may be centered differently) in a sequence selected to satisfy two simultaneous functions of the sensor.

Switch-while-scan optical system

An improved, compact optical system comprising a concave primary mirror and a convex secondary mirror. The primary mirror converges radiation to the secondary mirror. The secondary mirror comprises a lens having a first and a second surface. The second surface is coated with reflective material. The radiation received by the lens is refracted at the first surface, reflected back from the second surface, and then refracted once again by the first surface. The first and second surfaces have a shape for providing control of field curvature.

Compact optical system

An optical system having a dual field of view. The system includes a wide-angle objective comprising a lens, a concave primary mirror, and a movable convex secondary mirror having a first position and a second position. When in the first position, the secondary mirror permits the wide-angle objective to focus radiation. When in the second position, the secondary mirror prevents radiation from being focused by the wide-angle objective. The combination of the secondary mirror when in the second position and the primary mirror comprise a narrow-angle objective with the primary mirror converging radiation to the secondary mirror and the secondary mirror focusing radiation. Thus, the optical system has a wide-angle field of view whenever the secondary mirror is in the first position and a narrow-angle field of view whenever the secondary mirror is in the second position.

Optical system having a dual field of view

An objective lens system of the Double Gauss type wherein negative lens elements are symmetrically disposed on both sides adjacent the stop, each negative element being a cemented doublet comprising a double convex negative and a positive lens element. A cemented doublet positive lens component is next positioned at the outside of each of the negative elements and a single positive lens is positioned at the outside of each of the inner positive lens components.

Symmetrical 1:1 photographic objective lens

An aperture stop is provided near the detector imaging lens of a thermal imaging system to prevent the infrared detector from viewing portions of the thermal imaging system itself, particularly the walls of the optical housing and the housing of the scanner within the optical housing. This eliminates 'shading' problems which can occur in thermal imaging systems having a moving scanner within the optical housing.

Shade reducing aperture stop for thermal imaging systems

The disclosure describes a wide field reflective optical system comprising an afocal fore telescope and an imaging system. The afocal telescope comprises first and second confocal paraboloidal reflectors, an aperture stop located in front of the first reflector at a distance equal to its focal length, and a field stop located at the common focal point of the reflectors. The imaging system is an improvement of the Schmidt principle and comprises an aspheric corrector reflector that reflects radiation from the second paraboloidal reflector onto a plane reflector. The plane reflector is located in front of a spherical reflector that focuses radiation at its focal plane through an aperture in the plane reflector.

Growing community of inventors

Lexington, MA, United States of America

Irving R Abel