Abstract: A method of producing a superior quality of glass or other brittle material. The resulting end product is substantially stronger than conventional glass and exhibits greater strength consistency than was previously known. The techniques include various combinations of operations including substantially reducing the thickness of a blank of raw material; preparing formed edges including chamfered edges, rounded edges, and undercut edges; super polishing all edges and surfaces of a glass item; tempering the glass either thermally, chemically, or both; super polishing again after the tempering operation; and etching the glass after one or more of several steps in the process.

Abstract: A folded optical system is provided in the form of a telescope (20) for viewing distant objects. At least two optical elements (22, 24) have curved surfaces (32, 34) for imaging rays of radiation from a distant object. The two surfaces are positioned so as to permit a series of reflections therebetween for magnification of the resulting focal length of the optical system and diminution in the overall viewing angle so as to attenuate any light which may emanate from sources of radiation disposed off an optical axis which intercepts the object being viewed. One or more of the optical elements may be provided with apertures (30) through which rays of radiation are directed to a sensor (26) of the radiation, the sensor being positioned on a image plane to receive an image of the objects being viewed. First and second ones of the optical surface may be concave and convex, respectively, or alternatively, each optical surface may be concave with a folding mirror being utilized in the reflection of rays therebetween.

Abstract: A telescope employs folded optics with multiple reflections between a concave primary reflector, oriented towards incoming radiation, and a convex secondary reflector to produce reflected imaging rays which are nearly parallel to the optic axis of the telescope. Such geometry permits extremely long focal length (high f numbers) systems in a very overall short length, and the insertion of tubular barriers, both of which serve to intercept rays of radiation from a strong source which is sufficiently close, in an annular sense, to the object being viewed to produce a glare which would mask the image. The structure of the telescope includes apertures in both the primary and secondary reflectors situated along the optical axis to permit the reflected rays to pass beyond the secondary reflector to a point in front of the focus of the primary reflector as well as to a point behind the primary reflector, but which block out off-axis rays outside the field of interest.

Abstract: In a computerized tomography (CT) apparatus, in which a fan-shaped X-ray distribution is rotated around the body of a patient, it is possible to use a ring of non-rotating detectors disposed to receive the radiation after passage through the body along a cross-sectional slice. The ring may be tilted and precessed axially so that detectors on the same side of the body as the source do not interrupt the radiation. A second source is disposed on the opposite side of the body to the first to irradiate the detectors when moved out of the radiation from the first and thereby to examine a second cross-sectional slice at the same time as the first slice.

Abstract: A film cassette sensing and retaining unit for film handling apparatus. The unit is responsive to completed insertion of a cassette into the film handling apparatus to mechanically latch the cassette in position and to electrically condition and actuate the film handling apparatus. Upon termination of operation of the film handling apparatus, the unit is effective to unlatch and eject the cassette and thereby deactuate the film handling apparatus. A disabling mechanism is provided to prevent premature unlatching and ejection of the cassette in a particular circumstance.

Abstract: A control for varying the speed of advancement of film is described for use in a film projector in which the film is advanced by a shuttle tooth which engages perforations in the film and advances the film along a path between a light source and a projector aperture. The control includes a rotary shutter assembly having one or more shutter blades for interrupting the light from the light source. As the shutter assembly rotates, the shuttle tooth is reciprocated in the direction of film feed by a rotary cam having one or more cam lobes mechanically coupled to the shuttle tooth. The rotation of the cam lobes is synchronized to the rotation of the shutter blades such that the shuttle tooth is positioned for engagement with the perforations associated with the next successive film frame to be projected whenever a shutter blade interrupts the light source.

Abstract: A film handling apparatus blower system. The system includes a blower having a high-pressure, low-volume section and low-pressure, high-volume section. The high-pressure, low-volume section is a scroll-type centrifugal blower with a circular impeller of cellular material to minimize discernible noise, an axial intake port, and a high-pressure outlet port. The high-pressure outlet port is coupled to a duct which directs the output high-pressure air flow into a film cassette. The low-pressure, high volume section is also a scroll-type centrifugal blower having a bladed fan wheel, an axial intake port, and three low-pressure outlet ports. One low-pressure outlet port is coupled to a duct which directs output air flow to a location for flow adjacent the rearward portion of a projection lamp. A second low-pressure outlet port is coupled to a duct which directs output air flow to a location for flow adjacent the frontal portion of the projection lamp.

Abstract: A system for initiating operating mode change in a film handling apparatus in response to cessation of film movement incident to an end-of-film condition.