Abstract: An optical device for full duplex free space light transmission comprises a transmitting light source, having a transmitting optical axis and a radiated beam, and a receiving light detector having a receiving optical axis and a field of view. The transmitting optical axis and the receiving optical axis are nonparallel and substantially in the same plane.

Abstract: A self adjusting tuned resonant photodiode input circuit wherein an active feedback signal adjusts a reverse bias voltage across a photodiode to tune a resonant frequency to a center frequency. This results in a stable improved passband of the receiver front end.

Abstract: A wide-band tuned photodiode input circuit comprising: a photodiode; an step up double tuned network having an input and an output. The double tuned network is responsive to the photodiode. The input is capacitively coupled to the photodiode.

Abstract: A high efficiency resonant impedance transforming network for driving a high efficiency infrared LED and the associated method for decreasing the rise time and fall time of the LED to enable the LED to operate at higher frequencies than would ordinarily be possible. The resonant impedance transforming network includes an inductively coupled circuit that contains a primary winding and a secondary winding. The LED and at least one capacitor are coupled in parallel to the secondary winding of the transformer. The secondary winding charges the capacitors connected to it. During the rise time of the LED, the charge stored in the capacitors is discharged to the LED. The discharged charge supplements the current supplied by the secondary winding and the LED experiences a current spike during its rise time that significantly shortens the duration of the rise time. As the LED is conducting a space charge is contained within the LED.

Abstract: An electrostatic motor comprising a stator and a rotor, one of which is equipped with a plurality of lands to which a voltage is sequentially applied. The other of the stator and rotor is made of conductive material. Rolling contact is established between the stator and rotor along at least one line of contact. The rolling contact is controlled to repetitive first and second paths along first and second surfaces of the stator and rotor, respectively, in which the lengths of the first and second paths are different. Embodiments include a cylindrical motor, a flexible disk motor and a conical motor.

Abstract: An optical fiber switch in which a switchable fiber is switched to a first position by a first member inside the housing made of a shape memory material. This first member attempts to restore itself to an original shape heated above a first temperature and, in so doing, exerts a switching force on the switchable fiber. In a preferred embodiment, biasing means push the switchable fiber into a second position when the first means is below a second temperature. The first member exerts a force on the switchable fiber in a direction opposite to that of the biasing means of sufficient force to overcome the biasing force when the first member is above the first temperature. When the shape memory member is cooled, it assumes a distorted shape which allows the biasing means to control the position of the switchable fiber. In one embodiment, the biasing means is a second member also made of a shape memory material.

Abstract: An electrostatic optical fiber switch. An aperture in the switch housing allows for switching movement of the end of a fiber. This aperture is formed in part by a groove in which the depth and width of the groove increases continuously with distance toward the end of the fiber. This forms a smoothly curving surface for restraining and aligning the switching end of the fiber when the electrostatic field is applied. This arrangement substantially reduces the voltage required to operate the switch by prior electrostatic switches.

Abstract: The Fresnel lens concentrator is formed by a specially designed Fresnel lens and a solar cell located on the axis of the lens at its focal plane. The lens is designed so that its central facets project the light from the sun towards the outer periphery of the cell and facets progressively toward the periphery of the lens project light progressively toward the center of the cell to obtain a uniform distribution of light on the cell. Adjacent groups of facets of the lens project the light alternately in front and beyond the cell to maintain a constant light intensity for a certain depth of focus of the lens.

Abstract: A printed circuit board assembly is disclosed which includes a printed circuit board having in situ molded members for mechanically securing electrical and mechanical components and the like to the printed circuit board. The printed circuit board is manufactured using a method wherein a printed circuit board is initially prepared with the required printed circuit patterns and with apertures for in situ molded members and for the leads of the electrical components. The required molded members are then molded in situ in specified apertures of the printed circuit board. The electrical components are thereafter mechanically secured in place with the in situ molded members and the leads of the components are connected to the contact pads of the printed circuit pattern.

Abstract: The player is provided with a pair of spaced apart spine latching members which hook up with an inner record retaining spine as a disc record caddy is inserted into the player so that when the outer sleeve is withdrawn, the record/spine assembly is retained inside the player. A selected one of the spine latching members is equipped with a moveably mounted overtravel member which precludes the selected latching member from capturing the spine until the other latching member is also in position to latch up the spine. A connecting member rigidly intercoupling the latching members precludes the other latching member from capturing the spine until both latching members are ready to latch up the spine to ensure simultaneous latching of the spine.

Abstract: A focus servo system for optical disc record/playback apparatus includes three current drivers for maintaining the distance between an objective lens and an information surface of the disc substantially constant. One driver is a DC to low frequency amplifier which can drive the transducer over its full range to the mechanical stops. The second current driver is a DC to high frequency amplifier whose output at DC is limited to drive the transducer approximately twice the expected disc runout. At higher frequencies, the output is such that the displacement of the transducer does not exceed the displacement corresponding to DC value. In operation, the low frequency driver adjusts the DC operating point of the high frequency driver so that its output averages to approximately zero, thus decreasing the drive requirements of the high frequency driver. The third driver is a DC current source which sets the static operating point of the transducer.

Abstract: Recovery from a record of data recorded in an information track, comprising depressed areas of a given width, a given depth, and variable length, alternating along the length of the track with relatively non-depressed areas, is effected by an optical playback system. The playback system employs means for focusing light from a laser source on the information track as a light spot having a diameter which is diffraction limited. The focusing system includes an independent light source (e.g., laser) which impinges on the surface of the record as a circular spot which illuminates a plurality of elongated tracks. The circular spot is imaged by a lens system on to a detector plane which is positioned at a plane which is conjugate to the record surface.

Abstract: A plurality of like solar cell generators, each in the form of a segment of a circle, are spaced in a circular array on a face of a disc of insulating base material. They are formed by cutting a plurality of diagonal slits through a solar cell disc on the base material. A metallized grid structure is on the active cell face of each generator and an electrode in the form of a like circular segment juxtaposed with each generator is connected between the generator, on a side opposite the grid structure, and the base layer disc. The electrode has a terminal portion extending beyond the generator region. The slits electrically isolate the cells from each other.

Abstract: A thermally insulated light transmitting housing forms a chamber containing a desiccant and having a first gas port open to the ambient and a second gas port connected by a two way valve to a volume to be dried. Solar energy transmitted through the housing heats and dries the desiccant. The increased air pressure due to the heating of the volume to be dried causes the air from the volume to be expelled through the valve into the chamber. The desiccant is then cooled by shielding it from solar energy before the volume cools thereby increasing its moisture absorbing capacity. Then the volume is allowed to cool drawing dehumidified air through the desiccant and the valve into the volume to be dried. This cycle is then repeated.

Abstract: A method for fabricating a Fresnel lens comprising a plastic layer contacted to a transparent substrate by evacuating a chamber formed by the lens mold and the substrate through a pumping tube; flowing a liquid plastic through the pumping tube into the chamber; and venting the pumping tube to the atmosphere so that atmospheric pressure forces the plastic to fill the entire chamber.