Abstract: An optical sub-system has an optical element having a curved surface featured with a plurality of recurring surface tooling marks. The depth of any surface tooling mark is less than 0.2 wavelengths, whereby light is diffracted on the curved surface. A spatial filter blocks the diffracted light and passes the undiffracted light.

Abstract: A method and apparatus for making cylindrical glass preforms with convex, optical quality convex end surfaces is taught. A glass ball preform is placed on a heated lower platen. The temperature of the glass ball preform is raised to a temperature above the glass transition temperature of the glass ball preform. The glass ball preform is engaged with an upper platen. At least one of the upper platen and the lower platen is moved vertically to cause the gap between the upper platen and the lower platen to narrow to a predetermined dimension. Simultaneously, at least one of the upper platen and the lower platen is moved horizontally relative to the other platen to cause the glass ball preform to roll between the upper platen and the lower platen and form a cylindrical preform having a predetermined diameter, the cylindrical preform having convex, optical quality end surfaces.

Abstract: A method and apparatus are taught for molding glass lens elements from glass preforms. A glass preform is placed on a first mold surface of a first mold element which resides in a first sleeve segment. The temperature of the glass preform, the first mold element, the first sleeve segment, a second mold element, and a second sleeve segment are elevated to at least the glass transition temperature of the glass preform, the second mold element residing in the second sleeve segment. The second mold element and second sleeve segment are moved toward the first mold element and first sleeve segment to form a mold cavity, the mold cavity including a lens chamber and an annular channel projecting from the lens chamber. The glass preform is compressed in the mold cavity to form a glass lens element with the excess glass from the glass preform flowing into the annular channel.

Abstract: A method and apparatus for making cylindrical glass preforms with convex, optical quality convex end surfaces is taught. A glass ball preform is placed on a heated lower platen. The temperature of the glass ball preform is raised to a temperature above the glass transition temperature of the glass ball preform. The glass ball preform is engaged with an upper platen. At least one of the upper platen and the lower platen is moved vertically to cause the gap between the upper platen and the lower platen to narrow to a predetermined dimension. Simultaneously, at least one of the upper platen and the lower platen is moved horizontally relative to the other platen to cause the glass ball preform to roll between the upper platen and the lower platen and form a cylindrical preform having a predetermined diameter, the cylindrical preform having convex, optical quality end surfaces.

Abstract: A method for fabricating a mold tool for molding optical elements is taught which comprises heating a mold tool blank made from a vitreous material to a temperature above the glass transition temperature of the vitreous material; generating an axial viscosity gradient in the mold tool blank; pressing a punch into an optical quality mold surface of the mold tool blank, the punch including a pressing surface with a predetermined geometry for forming an optical feature; cooling the mold tool blank to a temperature below the glass transition temperature of the material; and removing the punch from the mold tool blank thereby creating the optical feature in the optical quality mold surface. The axial viscosity gradient is achieved by creating an axial thermal gradient.

Abstract: A method for making working mold tools for use in a compression molding process for molding optical glass elements from high temperature glasses having Tg's in the range of from about 400° C. to about 850° C. An yttria aluminosilicate glass is fabricated by traditional melting and casting processes to thereby make an amorphous base material having a minimum apparent viscosity of 1015 poise at the temperature at which the optical glass elements are to be molded. A mold preform is made from the base material. A first surface figure for the optical element to be molded with the working mold tool is defined. A second surface figure for a master mold tool and a third surface figure for the working mold tool are computed based upon the first surface figure and the coefficients of thermal expansion of the optical element, the master mold tool, and the working mold tool, the temperature at which the working mold tool is molded, and the temperature at which the optical element is to be molded.

Abstract: A method and apparatus is disclosed for compression molding arrays optical elements which may be later singulated. The apparatus includes first and second mold halves with the second mold half having a central nest and a plurality of predetermined negative optical surface features therein. A glass preform is placed in the central nest and the first and second mold halves and the glass preform are heated to at least the glass transition temperature of the glass preform. The glass preform is then pressed between the first and second mold halves to thereby form an integral array of optical elements with each of the optical elements being a positive of the predetermined negative optical surface features. The integrally formed array of optical elements is then cooled to below the glass transition temperature and removed from the first and second mold halves.

Abstract: A method and apparatus for stretching and aligning film sheets to a lenticular substrate comprising supporting members for the film sheet, two actuator assemblies positioned on opposite sides of a film sheet with a rigid bar member connecting the actuator means, "flexible" clamping members to engage the edges of the film sheet, a constraint member for the film sheet and lenticular substrate and detection means to detect errors in positioning of the film sheet image (substrate) and lenticular substrate.

Abstract: A prerecorded magnetic master web (54) and an unrecorded magnetic slave web (14), such as a photographic film having a magnetic coating, are brought into intimate contact for anhysteretic recording by wrapping the moving master web partially around a small diameter gimballed roller (66) positioned in close proximity to a rotating transfer drum (36); wrapping the moving slave web partially around a larger idler roller (34) positioned in close proximity to both the gimballed roller and the transfer drum; wrapping the slave web partially around the transfer drum with the master web wrapped outside the slave web; and evacuating a chamber or volume (68) formed among the webs, rollers and drum, to remove air from between the webs and cause them to converge into intimate contact at a nip upstream of a signal transfer zone in which a magnetic head (70) applies a decaying magnetic field to cause anhysteretic transfer from the master web to the slave web.

Abstract: An apparatus for cutting and feeding strips of web material includes a source (36) of an indeterminate length of web material; means (40-48) for withdrawing a predetermined portion (10) of web material from the source; a guide track (56,98-104) for receiving the lead end of the portion and guiding its edges along a curved path; a rotatable vacuum drum (60) positioned intermediate the ends of the curved path for gripping the portion; a cutter (50) for cutting the web to define a strip; and a motor drive arrangement (62,64,66) for rotating the vacuum drum to feed the strip along the curved path.