Abstract: A crystal pulling apparatus is disclosed which employs the Czochralski method. The crystal pulling apparatus is operated while a containing a crucible of molten material, while maintaining the growing chamber under a controlled pressure of less than atmospheric. In the event of a vacuum pump unexpectedly ceasing operation, power to the heater is terminated, thus allowing the molten material to solidify. In such an event, a second vacuum pump can readily be attached to the growing chamber thus restoring pressure control, and allowing power to the heater to be restored.

Abstract: The heater sling according to this invention is capable of lifting, moving and positioning a workpiece. In particular, it relates to a device and method for lifting a circumferential heater used in the manufacture of silicon ingots by the Czochralski method. The invention operates by mechanically extending a plurality of slings under a workpiece, lifting the workpiece, and placing it in a desired location.

Abstract: A method is introduced which improves gas flow characteristics within a reaction chamber used in a Chemical Vapor Deposition (CVD) system, thereby reducing the formation of Light Point Defects (LPDs) and improving epitaxial layer thickness control. This is accomplished by forcing the gas flow from its normally turbulent or non-uniform state into a more steady, linear, and controlled flow using one or more baffles. A steady flow of reactant gases significantly reduces the tendency of particles to move from a lower portion of the reaction chamber and settle onto the wafer during processing, thus reducing LPDs. It further allows a more controlled deposition onto the wafer which in effect improves the layer thickness control.

Abstract: A process for removing waxes from silicon wafer polishing plates is provided. The process includes the steps of providing submersion baths of an alkali soap, de-ionized rinse water, sodium hydroxide, and additional de-ionized rinse water, in which polishing plates are exposed. The process eliminates the use of methylene chloride from the process.

Abstract: A smoke detector unit with a fan that creates an airstream which flows through a smoke detector. Both the fan and the smoke detector are located within a housing that is mounted to the fuselage of an airplane. The smoke detector generates an output signal that is provided to an indicator when a threshold level of smoke is detected. The output signal is typically latched by a relay that is also located within the housing.

Abstract: A pressure sensitive paint is coated onto the surface over which a pressure distribution is to be measured, such as in a wind-tunnel test of an aerodynamic body. A pressure sensitive paint is a mixture of a photoluminescent-compatible, oxygen-permeable binder that is a mixture of silanol-terminated polydimethylsiloxane and methyltriacetoxysilane, and a photoluminescent active agent such as tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) chloride pentahydrate. The binder and active agent are placed into an appropriate amount of a solvent for the binder and the active agent, such as dichloromethane, and applied to a surface. In testing of the surface such as wind tunnel testing, the active agent quantitatively luminesces responsive to the local external pressure at the surface.

Abstract: A semiconductor laser device which provides enhanced carrier confinement. This device utilizes a single or multi-quantum well structure located between graded index confinement layers which are in turn between a pair of cladding layers. Semiconductor layers are selected such that the quantum well active region and confinement layers form a PN junction by being located between layers having N-type dopants on one side and P-type dopants on the second side for proper diode response. Within each confinement layer there is formed a plurality of multi-quantum barrier layers which serve to further increase the carrier confinement within the quantum well region by increasing the effective potential barrier within the graded index confinement region. The multi-quantum barrier layers are comprised of layers of the material forming the graded index confinement layers having alternating large and small concentrations of the material whose percentage is being varied in the graded index confinement layers.

Abstract: A metallic structural panel having a plurality of internal passages separated by supporting ribs and its method of fabrication. The fabrication assembly of the metallic structural panel is essentially comprised of a housing defining an internal cavity, a plurality of internal tubes, a means for segregating the internal cavity into a pressurized and an evacuation section and a means for establishing a pressure differential between the pressurized and evacuation sections. The metallic structural panel is superplastically formed and diffusion bonded such that independent passages are formed between supporting ribs within the internal cavity of the housing. Embodiments of the fabrication assembly for manufacturing metallic structural panel are also provided which produced a curved structural panel. These embodiments utilize a curved housing along with either curved end plates or curved internal tubes, depending on whether the supporting ribs are desired to be straight or curved, respectively.

Abstract: 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.

Abstract: A semiconductor active waveguide optical crossbar switch to allow optical signals to be routed to any number of ports with no net attenuation of signal strength. The optical crossbar switch is comprised of a network of optical waveguides wherein both lateral and transverse carrier confinement is provided. Redirection of the optical waveguide is accomplished by means of total internal reflectance turning mirrors. Furthermore, the optical waveguides are formed such that electrical current may be applied to the semiconductor structure to amplify the optical signal travelling therein. Electro-absorption switches formed from distinct metallic contacts overlying portions of the optical waveguides amplify the optical signal travelling through the waveguide underneath the switch if sufficient electrical stimulation is applied to the switch.

Abstract: A hand held laser apparatus containing a semiconductor laser diode switchably connected to a power supply. The output of the laser diode is focused and collimated by a pair of lens. Circuitry is provided to allow for either continuous wave or pulsed modes of operation as well as the capability of varying the pulsewidth of the laser. A guide laser or a light emitting diode is provided to guide the operator. The power level of the guide laser is limited so that it transfers minimal power to the workpiece but provides a visible line of laser light along which the output of the semiconductor laser diode will travel. A photodetector may be positioned between the laser diode and the lenses. Additionally, the amount of current delivered to the laser in continuous wave mode of operation or the pulse width and duty cycle of a pulse may be measured and displayed.

Abstract: A feed network for a multiterminal antenna which provides excitation to the antenna independent of ground. The feed network provides a voltage differential between terminals of the antenna instead of between a common ground point and a terminal so that the antenna achieves enhanced broadband performance via an attached balun for each coaxial cable. The feed network is comprised of a base, through which a plurality of coaxial connector extend, and a plurality of printed circuit boards positioned so as to define a centerline through the feed network. The printed circuit boards have a first side having a first, wide twin lead and a second side having a second, narrow twin lead such that the electrical signals conducted by the feed network are balanced between each pair of first and second twin leads. The twin leads of the printed circuit board are electrically connected to a corresponding connector of the plurality of coaxial connectors.

Abstract: There is provided by this invention an open-ended cavity microwave applicator apparatus for inducing current into an electrically conductive workpiece to be heated without need for the the applicator to be in contact with the workpiece. The microwave applicator is comprised of an open-ended housing that defines a cylindrical cavity which is coupled by an aperture to a waveguide which transmits the microwave energy from a microwave generator to the cylindrical applicator cavity. The microwave applicator is designed to operate in a subset of the circular TE.sub.mnp modes where m, n and p are the number of half wavelength variations in the standing wave pattern in the .theta., r,and z directions, respectively. The particular subset desired is the one in which m is equal to zero such that no current flows from the applicator to the electrically conductive workpiece. Of the subset of axially symmetric modes, TE.sub.0np, the preferred mode of operation is circular TE.sub.011.

Abstract: A capillary-tube energy-exchange system for transferring energy to or from an aircraft surface is comprised of inlet and exhaust manifolds interconnected by a plurality of Teflon capillary tubes. Fluid, either liquid or gas, is transferred from the inlet manifold through the capillary tubes to the exhaust manifold. During the fluid's flow, energy is transferred, typically from a warm fluid to an outer skin, in order to protect the aircraft's surface from ice accretions. The capillary tubes may be connected directly to ports formed in the manifolds; or, preferably, a chamber may be formed between the manifolds and the ends of the capillary tubes in order to transfer fluid therethrough. The energy-exchange system may be either an open or closed system.

Abstract: 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.

Abstract: 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.

Abstract: Disclosed herein is a semiconductor laser device comprised of a semiconductor substrate having deposited thereon at least one quantum well active region comprised of an alloy of the group consisting of GaInAsP and AlGaInAs sandwiched between upper and lower confinement layers of AlGaInAsP alloy. The laser device is further comprised of AlGaInP cladding layers.

Abstract: A semiconductor device structure capable of expanding a laser beam in one-dimension, collimating an expanding beam or focusing a nearly collimated beam. This semiconductor structure is typically comprised of three portions: a rib waveguide portion to propagate a beam of light in the quantum well region beneath the rib, an expansion region which incorporates a wider rib structure to allow the propagating beam to expand, and a rib etched lens portion to collimate the expanded beam of light. The shape of the rib etched lens portion is determined by Fermat's principle such that the optical pathlengths travelled by each ray of light are equated at a collimation plane positioned tangentially with the surface of the rib etched lens at the point at which an on-axis beam of light would strike the surface of the rib etched lens.

Abstract: A semiconductor laser device comprised of GaInP/AlGaInP materials which efficiently produces visible light output with improved carrier confinement and decreased threshold current density levels. The laser diode uses a strained quantum well positioned between a pair of graded index confinement layers which are in turn positioned between a pair of cladding layers. The active region is preferably comprised of Ga.sub.y In.sub.1-y P and the confinement layers are graded index layers comprised of (Al.sub.x Ga.sub.1-x).sub.0.51 In.sub.0.49 P in which the value of x is linearly graded from 0.40 to a maximum value selected from the range of 0.8 to 1.0 in a direction away from the active region. The cladding layers are comprised of (Al.sub.x Ga.sub.1-x).sub.0.51 In.sub.0.49 P in which the value of x is selected from the range 0.8 to 1.0. Bounding layers may be interdisposed between active region and the confinement layer on either side of the active region. The bounding layers are thin layers comprised of (Al.sub.

Abstract: A one-dimensional semiconductor laser array assembly typically comprising a one-dimensional semiconductor laser array, a heatsink upon which the laser array is bonded, and a lens assembly. The one-dimensional semiconductor laser array consists of a plurality of emitters with each emitter electrically connected in parallel to a power supply. The bonding agent, typically silver epoxy, must be of a uniform thickness so that the laser array is aligned properly upon the heatsink. The lens assembly is typically comprised of a refractive lens, typically of a bi-convex design, and a one-dimensional array of binary optical elements. The one-dimensional array of binary optical elements is designed such that each element has a front surface having a binary optic diffractive element etched thereon. The refractive lens and the one-dimensional array of binary optical elements are aligned and held in place by means of ears protruding from the heatsink.