Mcdonnell Douglas Corporation

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

Mcdonnell Douglas Corporatin

Gordon H Burkhart

Robert R Rice

Ronald A Ferrante

John E Jackson

Herbert G Koenig

Louis B Allen, Jr

Rudolf Herman Ott

Neil F Ruggieri

Joseph L Levy

Ronald Alfred Ferrante

Philip D Bear

James R Teague

James S Foresi

Christopher C Leung

Jimmie D Copple

The graded dielectric combiner, such as for a dual heads up display (HUD) combiner, is fabricated by depositing a predetermined number of dielectric layers upon a substrate and by thereafter selectively removing at least some of the dielectric layers from a graded portion of the dielectric combiner. As a result, the number of dielectric layers disposed upon the substrate will vary across the graded portion of the combiner. More specifically, the graded portion of the combiner may include a number of bands. A predetermined percentage of each band includes the predetermined number of dielectric layers, while the remainder of each band includes less than the predetermined number of dielectric layers. Since the dielectric layers are deposited in a conventional fashion, however, the thickness of each remaining dielectric layer will be uniform across the substrate. The graded dielectric combiners can thereafter be assembled to form a dual HUD combiner having first and second combiners in which one or both combiners are graded within the overlap region, thereby reducing, if not eliminating, the dark band and other visual nonuniformities introduced by the overlapped combiners of conventional dual HUD combiners.

Graded dielectric combiner and associated fabrication method

An aspheric cylindrical lens for collimating, with low optical aberrations, the asymmetrically diverging beams of diode laser arrays and a method of fabricating such lenses. The aspheric cylindrical lens are formed from a plano-spherical optical lens. The planar surface of the lens is then optimized such that each ray of light from a diverging input light source will travel the same optical path length in reaching a predetermined collimation plane. Due to the optimization process, an aspherical front lens surface is formed from the initial planar lens surface. The aspheric cylindrical lens may be formed by means of a drawing process in which a master lens element is drawn into a plurality of aspheric cylindrical lens elements. In such a drawing process, a master lens element is manufactured having a spherical back lens surface and an optimized front lens surface which are proportionately identical in cross-section to resulting aspheric cylindrical lens, but substantially larger in physical dimensions. The numerous optimized aspheric cylindrical lens resulting from the drawing process may thus be produced in an economical and reliable manner.

Aspheric cylindrical lens and method of fabrication

A cylindrical lens and a binary optical element for collimating with low optical aberrations an asymmetrically diverging input wavefront. The binary optical element is formed on a planar substrate on which a binary optical diffraction pattern is etched on the front surface thereof. The binary optical diffraction pattern is designed such that each ray of light from the diverging input light source will travel the same optical path length or vary from that optical path length by an integer multiple of the wavelength of the light in travelling from its source to its exit from the front surface of the binary optical element. A beam angle alignment element is also provided, to be utilized in conjunction with a cylindrical lens and the binary optical element, for correcting angular misalignments of diode lasers whose output wavefront has an optical axis which is either above or below the plane in which the active region is formed. The beam angle alignment element is also a planar substrate on which a binary optic diffraction pattern is etched. The binary optic diffraction pattern of the beam angle alignment elements diffracts the wavefront exiting from the binary optic element so as to align the wavefront about its optical axis. The cylindrical lens, the binary optical element, as well as the beam angle alignment element may be used in conjunction with a single diode lasing element, as well as a one dimensional or a two dimensional diode laser array.

Hybrid binary optics collimation fill optics

A hybrid lens for collimating, with low optical aberrations, an asymmetrically diverging input wavefront. The hybrid lens has a front surface which serves to diffract the input wavefront and a back surface which serves to refract the wavefront. Embodiments are described comprised of either a single plano-convex optical lens or a pair of lenses, one of which is a plano lens and the other or which is plano-convex. In either alternative, the convex surface is spherical. The planar surface of the single plano-convex lens or the back lens surface of the plano lens is optimized such that each ray of light from a diverging input light source will travel the same optical path length in reaching a predetermined collimation plane. This optimization is done by means of binary optic technology which uses a reactive-ion etch to form the requisite eight-level binary optic diffraction pattern. The widths of the fringe patterns generated by the three masks determined by calculations of the optical path difference between on-axis and off-axis rays which are traced through the hybrid lens.

Hybrid diffractive/refractive lens

A sliced transform lens is used to combine and focus the optical output signals of a planar M by N laser diode array onto M detector elements in a linear detector by displacing lens slices. A sliced transform lens is used to separate the composite image of the laser diode array on the detector plane into ten spots (400 emitters per spot) by displacing the lens slices relative to each other collimated He-Ne laser beam was used to examine the sliced transform lens and the linear detector array was used to measure the image sizes and the crosstalks between the images. The results show the minimum separation is approximately five detector spacings apart. The lens elements are cut from a bulk material (BK-7) and ground to desired thickness and parallelism. Then the elements are 'glued' together with standard optical wax compound and ground to the prescribed focal length. THe lens slices are cut before grinding, hence the composite lens is symmetric and zero-curf configuration is preserved. This relaxes the collimation requirement of the incoming light to some extent. The lens is then polished and ready for application.

Transform lens with a plurality of sliced lens segments

A cylindrical laser rod has a cylindrical sleeve surrounding it, the cylindrical sleeve having a reflective coating applied to its periphery with one or more transparent flats or slits being positioned in an equiangular fashion about the sleeve. At each slit, a focus lens and a retro-reflecting lens is mounted thereto, with the focal lens being aligned in an off axis orientation such that a linear laser diode array can be aligned with the focus lens and its beam directed in a off axis path through the laser rod for reflection a plurality of times through the sleeve and rod, the beams being returned along its reflecting path by the retro-reflector to maximize the coupling between each linear laser diode array and the laser rod.

Laser diode coupler

A lens is produced on the end of a single mode optical fiber by first coupling light into the fiber so that the light projects out the end of the fiber on which the lens is to be produced. The fiber end is then dipped in and out of a drop of negative photoresist and held in a vertical position while the photoresist wicks up the fiber and dries. The dipping and drying is continued until a sufficient lens of photoresist is built up which lens tends to build in the desired shape due to the Gaussian distribution of the light projecting out the end of the fiber and the flow of photoresist up the fiber.

Process for producing guided wave lens on optical fibers

A solid state laser rod and a mount through which heat is dissipated from the rod are joined together at a bond comprised of a reflective layer on the surface of the rod, a barrier layer over the reflective layer, and a solder layer between the barrier layer and the mount. The reflective layer may be applied by sputter or other deposition procedures and is highly reflective in the region of the spectrum at which the laser operates, thus insuring optimum efficiency for the rod. The barrier layer may be applied to the reflective layer by the same deposition procedure, and it is impervious to the solder so that the solder does not penetrate it and scavenge the reflective layer. The solder should have a low melting point so as to avoid setting up excessive mechanical stresses in the rod when the solder solidifies. Both the mount and the barrier layer may be covered with a wetting layer prior to soldering to achieve better adhesion of the solder.

Bond and method of making the same

An electrooptic crystal having improved characteristics including an improved light extinction ratio and a process of making same including etching certain portions of the lateral surfaces thereof so as to relieve surface and other strain in the crystal.

Process for surface work strain relief of electrooptic crystals

An improved laser construction having relatively simple single element means located in the laser cavity for simultaneously mode-locking and frequency doubling the laser output, said single element means including a crystal such as a non-linear barium sodium niobate (BSN) crystal properly excited to achieve acoustooptic loss modulation as well as to mode-lock the laser output, and means for locating the crystal within the laser resonator cavity.

Growing community of inventors

St. Louis, MO, United States of America

Gordon H Burkhart