Polaroid Corporation

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

James G Baker

William T Plummer

Jon E Van Tassell

A lens system for a folding reflex camera is provided. The system includes: (a) a first group on the object side of the system's stop which (i) has a positive dioptric power, (ii) includes an aspheric surface, and (iii) has a concave surface adjacent to the stop; and (b) a second group on the image side of the stop consisting of either a single positive component or the combination of a single positive component and one or more focusing elements. The system includes at least two elements made of materials differing in dispersive powers where at least one of the elements is of plastic. The system can comprise just two plastic elements and even with such a simple configuration achieves excellent optical performance including a relatively flat field, relatively low distortion, and at least partial correction for lateral chromatic aberration.

Compact objective lens

Zooming optical systems in which the effective focal length changes required for changing image scale and focus maintenance are brought about by movement of various system elements across the optical axis rather than along it as is the usual case. The zooming systems are suitable for use in a variety of applications including visual instrumentation and photographic systems.

Zoom lens

A two-element viewfinder comprising a mirror distorted in the form of a generalized polynomial shape, an eye lens, and a Fresnel mirror for use in a reflex camera with a taking objective and a reflex mirror.

Camera and two-element viewfinder

Optical elements shaped in accordance with preferred analytic functions which permit the elements to be relatively rotated about one or more pivots decentered with respect to an optical axis to simulate the dioptric action of a well corrected rotational lens element of variable power that can be used to maintain focal setting over a large range of object distances. The optical elements can be used in pairs, singly with mirror images of themselves, or they can be incorporated in more elaborate systems to provide focusing action.

Analytic function optical component

A compact convertible photographic objective that is separable into two working components consisting of a front substantially afocal component that can be rotated or translated laterally into or away from a coaxial position with a rear component which normally is fixed in position on an assigned optical axis. Movement of the front component into coaxial alignment with the rear component increases the focal length of the combination so that the two components can be used for telephoto purposes.

Compact afocal attachment for use with photographic objectives

A five element photographic objective including four elements fixed in a generally symmetric arrangement and a transversely movable refracting plate of preferred shape for maintaining the focal setting of the objective over a large range of object distances. One of the four fixed elements and the refracting plate each include at least one surface whose shape is in a nonrotational aspheric and mathematically describable by a polynomial of at least fifth order.

Optical system utilizing a transversely movable plate for focusing

A thin optical panel formed of two, preferably identical, but opposed spaced apart lenticulated plates structured to form a series of regularly spaced apart line images of the sun, one line image for each associated pair of lenticular elements in a plate. All of the line images formed move short distances as a group across a plane behind the panel during the diurnal motion of the sun. The images thus formed can be tracked with an array of thin silicon ribbons or the like to convert solar energy to electrical energy. Two spaced apart panels arranged to move in their own planes relative to one another continuously collimate solar energy emerging from the second panel which thereafter can be focused onto a single silicon ribbon. With the optical axes of the lenticules of the second panel selectively offset with respect to those of the first panel, focusing onto a single silicon ribbon is achieved by the panels themselves.

Multielement optical panel

Wide angle optical objectives for use in aerial mapping cameras to provide improved resolving power and improved contrast rendition derived from the pattern of glass types and lens data employed. The outermost elements are weakly positive menisci to produce an initial convergence of rays before the mating negative elements are introduced thereby keeping the physical length of the system within modest proportions. Strong negative elements lying outside of centrally located strong positive elements provide favorable illumination over a wide angle field. Wafer elements near the center of the system serve to minimize chromatic astigmatism and to reduce the actual sagittal depth of the aspherics. Wafers of high index flint glass are located next to the central stop in order to obtain good chromatic spherical correction in the tangential rays over the field.

Lens system having wide angle objectives

For use in an afocal, periscopic viewfinder system of the type having four spaced apart elements, all equi-convex with aspherized surfaces and identical in pairs, and a central stop, there is provided a novel central reimaging system that is structured to increase the overall length of the viewfinder system without substantially changing the other characteristics or optical performance of the viewfinder system.

Periscopic viewfinder system for use in photographic cameras

A compact substantially afocal lens comprising two components each including two elements adapted for use as a magnifying attachment for an objective with an internal stop. Compactness in an afocal lens of good performance is obtained by the use of a strongly curved first surface followed by other strongly curved surfaces, by the choice of alternating high and low indices of refraction for the successive negative and positive elements, respectively, and by correcting the lens less well for longitudinal color and distortion than for the other aberrations.

Compact four element afocal lens

A compact, rigid camera for use with self-developing film utilizes a prism element having an exit face overlying the film and which is both reflective and transmissive to fold the optical path of useful light rays between an objective lens and a film plane in a relatively small volume. A prism entrance face is oriented with respect to the reflective/transmissive exit face so that entering light is totally internally reflected at the exit face to at least two other faces of the prism which are reflective and oriented to return the light to the exit face substantially along its perpendicular. The exit face is coextensive with the film plane so that the reflected light transmitted through the exit face exposes the film. In one form the exit face of the prism is planar and closely spaced from the film plane. In another form the exit face has two mutually inclined planar surfaces, each of which internally reflects one image beam and transmits another beam internally reflected from the other face. In the latter form an auxiliary emergent prism is interposed between the exit face reflective/transmissive surfaces and the film plane.

Growing community of inventors

Bedford, NH, United States of America

James G Baker