Abstract: A thermally controlled servo system in which a member supporting the drive for a device to be accurately positioned is moved relative to a stationary support member in response to changes in temperature of an elongated, tensioned member. Changes in temperature of the tensioned member are achieved by regulating the current flow through the tensioned member in accordance with a control signal derived from an error signal generated by the device to be positioned.

Abstract: A transformer coupled, resonant feedback, tuned oscillator circuit in which the output current to a low power variable load is maintained constant by incorporating into the circuit an additional feedback circuit which provides a DC error voltage to the oscillator circuit enabling it to compensate for variations in core loss resistance, variations in load, and variations in other circuit parameters. The feedback circuit includes two separate electronic switches both of which are connected to a voltage averaging circuit and an error amplifier which compares the voltage of the averaging circuit against an adjustable reference voltage whereby the DC error voltage is generated and supplied to the center tap of the transformer feedback winding. Because oscillator transformer core resistance variations can be compensated for, the design of the oscillator transformer can be simplified and readily available, not specially designed, transformers can be utilized.

Abstract: A recording apparatus in which the cantilevered arm supporting a recording device has a smoothly curved surface adjacent the flexure spring joining the arm to a carriage whereby a rolling pivot is provided such that the bending stress on the flexure spring is minimized and is constant and independent of the degree that the cantilevered arm is raised. An end of the cantilevered arm is held against the carriage by a spring, one end of which is coupled to a translation mechanism which permits the recording device load force to be adjusted.

Abstract: A pliant magnetic disc recording assembly having two adjacent transducer heads, with the center lines of the heads oriented at an angle to the axis of rotation of the magnetic disc and arcuately spaced with respect to such axis of rotation. The bearing surface of each head has a radius, and each bearing surface extends into the plane of the disc, whereby the disc has a wavy contour over the heads. The orientation, position and shape of the heads causes the disc to have a large wrap angle about each head whereby wear producing forces are distributed over a large area of the disc which lowers stresses on the disc.

Abstract: An address mark code for use with Modified Frequency Modulation encoding wherein (1) the first bit of the 8 bit address mark byte is always zero, (2) the address mark byte eliminates a clock pulse between the second and third zero of a string of at least four zeros, (3) the address mark byte contains the binary pattern 101, and (4) the spacing between data pulses and/or clock pulses of the address mark byte is between 1T and 2T where T is the width of a data cell of the address mark.

Abstract: A solid state laser in which transverse mode control is achieved by a layer of non-uniform thickness adjacent the laser active region and longitudinal mode control is achieved by a periodic structure formed in the laser substrate. The layer of non-uniform thickness is provided by forming the layer on a channeled substrate, and the teeth of the periodic structure extend in a direction transverse to the direction of the channel.

Abstract: A resonant circuit sine wave power supply in which the resonant circuit thereof is coupled to ground through alternately conducting complimentary emitter followers during the portions of the voltage generation cycle when the resonant circuit is not coupled to a dc supply, whereby a power supply that is substantially non-dissipative of heat is provided.

Abstract: A laser array comprised of a plurality of stacked emitting or active regions which are in sufficiently close contact to each other that light from each active region is coupled to the light from the adjacent active regions to form a phase-locked laser array with low composite beam divergence perpendicular to the plane of the rectifying junction of the active regions.

Abstract: A channelled substrate diode laser in which transverse and longitudinal mode control is achieved by having the laser current profile flat over the substrate channel. A flat current profile over the substrate channel, which is achieved by having the width of the path of the pump current greater than the width of the channel, causes waveguiding to be influenced only by a fixed channel guiding factor.

Abstract: A scanner using spatial modulation of the light profile incident upon an acousto-optic modulator in which the deflector clear aperture window is decentered from the optical axis of the system so that the light profile falls just within one edge of the deflector clear aperture window. One advantage of the decentering of the optical alignment is increased system frequency response due to transmission of only one sideband of the light profile, which in terms of a printing systems means increased resolution. Loss of laser light due to decentering of the optical alignment can be minimized by using a single sideband signal as the modulator drive signal instead of the conventional double sideband drive signal. Distortion of the light profile due to decentering of the optical alignment can be reduced by predistorting the single sideband drive signal supplied to the acousto-optic modulator.

Abstract: An all mirror facet tracking system including first and second spherical mirrors. Both of the mirrors can be located along the same system axis on opposite sides of a rotating multi-faceted polygon which has its axis of rotation on the system axis. To reduce coma, the spherical mirrors are located along orthogonal system axes and a flat folding mirror is provided between the two spherical mirrors to reduce the angle of incidence of the chief ray with the second spherical mirror.

Abstract: A light beam scanner of the moving interference fringe pattern type which includes a body of semiconductor material having a source of coherent radiation and wave guides for guiding the coherent radiation along a plurality of spatially displaced paths which are optically uncoupled, and means associated with the spatially displaced paths for producing relative phase changes between radiation in the different paths whereby interference fringes in the far field are spatially scanned. In addition, wavelength modulation of the laser over a range of about 80 A can be achieved. The source of the coherent radiation can be a single laser or a plurality of optically coupled lasers, and the optical uncoupling can be achieved by spatial displacement of the paths or by insertion of a high loss medium between the paths.

Abstract: A laser beam scanner in which a single-lobe propogates radiation pattern through an electrically variable asymmetric electrical charge distribution. Because the electrical charge distribution determines the real and imaginary parts of the refractive index of the material through which the radiation pattern propogates the radiation pattern may be deflected by changing the charge distribution profile.

Abstract: An LED in which the recombination region is comprised of a first layer which is degenerately doped (.apprxeq.10.sup.19 /cm.sup.3) and a second layer which is less degenerately doped (.apprxeq.3.times.10.sup.18 /cm.sup.3). The reduced doping of the second layer provides a depletion region which is wider than the depletion region of conventional LED's whereby carrier tunneling (and non-radiative recombination from such tunneling) is reduced. The second layer is only as thick as necessary (.apprxeq.150A) to reduce tunneling (excess current) significantly which permits substantial radiation by improved carrier injection into the first (heavily doped) portion. The heavy doping of the first layer allows the LED to respond very quickly to switching signals whereby improved light output is achieved with a great reduction in non-radiative recombination due to tunneling.

Abstract: An optical storage medium in which the effect of optical interference is utilized to provide information storage. Heating of selected portions of the optical storage medium causes a permanent change in the wavelength and intensity of the interference fringes of the optical storage medium, and those changes give rise to large changes in light reflectivity at the initial interference fringe wavelengths, and hence gives rise to an optical pattern that is readily detectable. Preferred storage medium materials include alloys of the Ge-Se-S-Te group overlaying a metallic layer.

Abstract: A resistor array formed by the process of forming a plurality of holes or grooves in an electrically insulating substrate, filling the holes or grooves completely with a flowable, electrical resistance material, and then hardening the resistance material. The resistance material can be comprised of an electrically non-conductive thermally setting base material throughout which electrically conductive particles are dispersed, or the resistance material can be colloidal or a suspension. The value of the resistors is determined by the volume resistance of the resistance material and the volume of the holes or grooves, the resistance increasing as the length of the holes or grooves increases and decreasing as the cross-sectional area of the holes or grooves increases.

Abstract: A process of fabricating switching device electrodes with an integral dielectric layer. The method permits the dielectric layer to serve also as the photoresist during the electrode etching step of the process.

Abstract: An autonomous processor for displaying on a video tube both text characters and facsimile data. To conserve memory space the facsimile data is stored in compressed form and is decompressed or unfolded in synchronism with the vertical and horizontal deflections in the video tube. Similarly the text characters are stored in coded form, together with interspaced commands, both inscribed in a list memory. Each character code in the list then selects an appropriate dot matrix from a font memory which also contains displacement data. Selected lines of the font dot matrices are then addressed by row coordinates to form a horizontal video signal, which is accumulated in a ping pong buffer concurrently unloading into a video register. This same video register merges the facsimile data which is concurrently unfolded.

Abstract: A rear projection screen which eliminates speckle by only linear diffuser surface motion. One of a pair of closely spaced plates of the rear projection screen is maintained fixed while the other plate is driven such that it has a linear motion relative to the fixed plate. The plates are optically transparent and have their facing surfaces etched or coated to provide adjacent diffusing surfaces. The driven screen is supported by L-shaped spring metal straps thereby providing a strong plate support assembly which can operate at low noise levels and with low drive-power requirements.

Abstract: A high voltage power supply is regulated using a light dependent resistor. A feedback circuit from the load controls the input to a light emitting diode which is optically coupled to a light dependent resistor connected in series with the load. Increases in the load current tend to reduce illumination on the light dependent resistor, thereby increasing the resistance of that circuit element which reduces the load current. The converse is also true. Regulation may be applied to a D.C. power source or to an A.C. power source by developing a signal indicative of average current level and applying it to the light emitting diode to control the light dependent resistor. The high voltage power control of the invention is particularly useful in regulating corotron voltage levels in a xerographic reproduction device.