Patents by Inventor David D. Thornburg

David D. Thornburg has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4570149
    Abstract: A touch tablet is provided containing two sheets of insulating material each of which contains a plurality of spaced apart conductive lines. A resistive strip on each sheet contacts and connects electrically one end of each of the plurality of conductive lines on that sheet. Each resistive strip functions as a potentiometer. Mounted between the two sheets and spaced apart therefrom is a conductive middle sheet. The first and second sheets are mounted such that the first and second sets of a plurality of conductive lines on these sheets are orthogonal to each other. A user presses on one of the two sheets to bring all three sheets into contact. The impedence of each potentiometer is a function of the contact point. The potentiometer is used as part of an RC circuit to provide a variable time constant representative of the coordinate of the contact point.
    Type: Grant
    Filed: March 15, 1983
    Date of Patent: February 11, 1986
    Assignee: Koala Technologies Corporation
    Inventors: David D. Thornburg, George M. White, III
  • Patent number: 4484026
    Abstract: A touch tablet for use in entering data into a computer or graphics display device comprises a first four-sided sheet containing a resistive material on one surface thereof, a second four-sided sheet containing a resistive material on one surface thereof and a spacer for holding the first sheet apart from the second sheet. The first sheet is oriented relative to the second sheet such that the resistive material on one of the two sheets faces the resistive material on the other sheet. Each sheet contains conductive strips formed on two of the four sides of the sheet in contact with the resistive material. A potential is applied across the conductive strips on one of the two sheets. The input lead to an output amplifier is connected to the two conductive strips formed on the other of the two sheets. A user presses the first sheet into conduct with the second sheet and the output voltage from the output amplifier is representative of one of the two coordinates of the point of contact between the two sheets.
    Type: Grant
    Filed: March 15, 1983
    Date of Patent: November 20, 1984
    Assignee: Koala Technologies Corporation
    Inventor: David D. Thornburg
  • Patent number: 4465908
    Abstract: A hand controller for use in controlling the motion of a cursor on a video display comprises a spherical surface on which is mounted a flat plate. On the bottom of the flat plate is a unique electrical switch capable of indicating the direction in which the flat plate is rocked over the spherical surface. Attached to the bottom of the flat plate adjacent the spherical surface is a spring consisting of a substantially flat center portion and four spiralling arms extending from the periphery of said center portion to attach to the structure on which the spherical surface is mounted. When the flat plate is rocked over said spherical surface, the spring generates a restoring force which, upon removal of the rocking force, restores the flat plate to its nominal position. The spring makes possible rocking motion of the flat plate over the spherical surface without pinning the flat plate to a point on the spherical surface.
    Type: Grant
    Filed: August 16, 1982
    Date of Patent: August 14, 1984
    Inventors: William M. Griffith, Gordon H. May, David D. Thornburg
  • Patent number: 4321441
    Abstract: A keyswitch arrangement including an array of switches formed on a flexible dielectric substrate wherein each switch includes a stationary conductive contact lying in the plane of the substrate and an adjacent movable conductive contactor carried on a flap cut out of the substrate and bent along a hinged line located between the contact and the contactor. The stationary contact and movable contactor are both formed on the same side of the substrate and are normally disposed in the open switch position in confronting relationship with the flap at an acute angle to the plane of the substrate.
    Type: Grant
    Filed: February 4, 1980
    Date of Patent: March 23, 1982
    Assignee: Xerox Corporation
    Inventor: David D. Thornburg
  • Patent number: 4318096
    Abstract: A graphics input device for use with location indicating means to present graphic data upon a computer controlled visual display. The device includes a pen having a housing within which is disposed a conductive stylus shaft, one end extending beyond the housing to serve as the writing tip. A cylindrical off-axis pressure transducer encircles a portion of the stylus shaft within the housing, adjacent its writing end, for generating a variable output electrical signal proportional to the variable off-axis force applied to the stylus independently of the rotational orientation of the pen. A display processing and control system receives the variable signals and modifies a visual characteristic of the graphic data in response thereto.
    Type: Grant
    Filed: May 19, 1980
    Date of Patent: March 2, 1982
    Assignee: Xerox Corporation
    Inventors: David D. Thornburg, Robert M. Flegal, Tat C. Lam
  • Patent number: 4315270
    Abstract: A backup electrode arrangement comprises a resilient insulating member across one surface of which are a plurality of electrode segments separated from one another and comprising an electrically resistive material forming a shoe. The electrode shoes provide pressure engagement against an array of recording electrodes in an electrostatic recorder with a recording medium disposed therebetween. The electrical resistivity of the shoes is sufficiently high to protect the recording electrodes from pinhole shorts in the dielectric layer of the recording medium. With the backup electrode positioned directly opposite to the recording electrode array, the charging path impedance is reduced permitting reduction in writing speed and a corresponding increase in overall recording time.
    Type: Grant
    Filed: December 6, 1979
    Date of Patent: February 9, 1982
    Assignee: Xerox Corporation
    Inventors: William A. Lloyd, David D. Thornburg
  • Patent number: 4313113
    Abstract: A graphic input device for controlling the movement of a cursor upon a visual display. The device includes a number of variable resistance pressure transducers corresponding to the primary orthogonal directions of cursor movement. Each pressure transducer comprises a first electrode for selecting the direction of movement and a second electrode spaced from the first electrode, one of the electrodes being made of an electrically resistive elastomeric material. A manipulable force transmitting device is provided to move the electrodes toward one another and into contact, the contact area being variable with the force applied, so that the resistance across the electrodes is high when the contact area is small and lower when the contact area is larger. The device is connected to the visual display via an electrical circuit which supplies signals to move the cursor in a selected direction at a speed inversely proportional to the resistance condition.
    Type: Grant
    Filed: March 24, 1980
    Date of Patent: January 26, 1982
    Assignee: Xerox Corporation
    Inventor: David D. Thornburg
  • Patent number: 4288836
    Abstract: A tri-state capacitance controlled keyswitch having a deformable concave electrode moveable by means of an actuator toward and away from a pair of capacitor plates underlying a dielectric layer in order to change the capacitive coupling between the capacitor plates. The electrode is normally remote from the dielectric layer in a weak capacitance open circuit position, a first higher capacitance closed circuit position exists when the electrode is undeformed and is in contact with the dielectric layer, and a second highest capacitance closed circuit position exists when the electrode is deformed and is in contact with the dielectric layer.
    Type: Grant
    Filed: May 29, 1979
    Date of Patent: September 8, 1981
    Assignee: Xerox Corporation
    Inventors: David D. Thornburg, Brian Rosen
  • Patent number: 4264646
    Abstract: The method of selectively depositing a metal pattern on the surface of a laminar film comprising a dielectric substrate having a co-extensive metallic layer and a ceramic overlayer. A desired metallic pattern may be formed on the surface of the film by applying a releaseable mask in those regions of the film surface where plating of the surface is not desired, catalyzing the unmasked regions of the film surface, removing the mask from the film surface and thereafter immersing the film in an electroless plating bath whereby only the catalyzed regions are plated with the electroless metal of the bath. The preferred film has gold intermediate layer upon which electroless nickel or copper pattern plating is accomplished.
    Type: Grant
    Filed: March 12, 1979
    Date of Patent: April 28, 1981
    Assignee: Xerox Corporation
    Inventors: David D. Thornburg, Thomas J. Kloffenstein, Jr.
  • Patent number: 4223088
    Abstract: A method of forming a defined conductive pattern in a laminar film comprising a thin gold layer interposed between an insulating substrate and a ceramic overlay is disclosed. A base etchant is employed to remove the thin ceramic layer but itself will not etch or remove the gold film layer. Upon removal of the ceramic layer, the exposed gold layer may be removed without any chemical treatment or assistance. Such removal may, for example, be accomplished by fluid agitation or exposure to a fluid stream or by swabbing. A pretreatment of the film surface prior to etching enhances the adhesion of the photoresist subsequently applied to the film surface.
    Type: Grant
    Filed: January 26, 1979
    Date of Patent: September 16, 1980
    Assignee: Xerox Corporation
    Inventor: David D. Thornburg
  • Patent number: 4181913
    Abstract: Semiconductor devices which exhibit negative differential resistance and comprise a semiconductor material in contact with an electrode and a resistive film layer, preferably comprising an alloy of nickel and chrome is disclosed. The slope of the negative resistance region and the current filament area can be varied by altering the sheet resistivity of the resistive film layer. This allows the semiconductor device to be incorporated in a single monolithic thin film integrated circuit in which the thickness of the semiconductor layer utilized in the integrated circuit is constant. A method for fabricating the aforementioned semiconductor device is also disclosed.
    Type: Grant
    Filed: May 31, 1977
    Date of Patent: January 1, 1980
    Assignee: Xerox Corporation
    Inventor: David D. Thornburg
  • Patent number: 4177421
    Abstract: A capacitive transducer comprises two plate electrodes positioned in juxtaposed relationship on one surface of a dielectric substrate and an array of segmented electrodes provided on the opposite side of the substrate. Capacitive coupling is achieved between the segmented electrode array and the two plate electrodes. The geometrics of the transducer are such that increasing capacitive coupling is obtained along the main axis of the transducer. An AC signal supplied to one of the plate electrodes of the transducer can be attenuated by physically touching the segmented electrode array. Attenuation can be varied by moving such physical contact along the main axis of the transducer. One or more transducer can be used in a coordinate arrangement to provide an X-Y position indicating device.
    Type: Grant
    Filed: February 27, 1978
    Date of Patent: December 4, 1979
    Assignee: Xerox Corporation
    Inventor: David D. Thornburg
  • Patent number: 4172757
    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.
    Type: Grant
    Filed: October 17, 1977
    Date of Patent: October 30, 1979
    Assignee: Xerox Corporation
    Inventor: David D. Thornburg
  • Patent number: 4162538
    Abstract: A thin film programmable read-only memory is provided which comprises an X-Y matrix of conductors, the cross points of which are connected together by a switch element comprising a current-controlled negative differential resistance (CNDR) device in series with a semiconductor fuse. At low bias levels corresponding to read signals, the element behaves as a non-linear resistance. At large bias levels corresponding to write signals, the element will be driven to its negative differential resistance characteristic, the switching element becoming a permanent open circuit when the fuse blows. The symmetrical switching characteristics of the CNDR device allows the function of the X conductors (input or address lines) and Y conductors (output or word lines) to be transposed in that the address information can be applied to the Y lines, the output appearing at the X lines.In an alternate embodiment, a threshold switching (TS) device is utilized in place of the CNDR device.
    Type: Grant
    Filed: July 27, 1977
    Date of Patent: July 24, 1979
    Assignee: Xerox Corporation
    Inventor: David D. Thornburg
  • Patent number: 4126824
    Abstract: A progressively shorted tapered resistance device including a body of material which undergoes an irreversible resistance decrease when heated beyond a threshold temperature in operative association with a tapered electrical resistance element which develops a non-uniform temperature profile when electrically energized. Upon sufficient energization, the tapered resistor element will cause portions of the heat sensitive material to be heated beyond its threshold temperature resulting in a shorting out of a portion of the tapered resistance element. The amount of the tapered resistance element shorted out is measured at low currents to provide an indication of the energizing current.
    Type: Grant
    Filed: April 21, 1977
    Date of Patent: November 21, 1978
    Assignee: Xerox Corporation
    Inventors: David D. Thornburg, Roy J. Lahr
  • Patent number: 4121153
    Abstract: An improved analog meter is provided having no moving parts. This meter comprises a tapered resistor device having a tapered, electrically resistive element which develops a non-uniform temperature profile on electrical energization and a heat sensitive element operatively associated with the tapered resistive element. The heat sensitive medium employed is a reversible medium which either undergoes a change in color or contrast when heated to an appropriate temperature and when viewed under appropriate illumination. A method of metering employing this device is also disclosed.
    Type: Grant
    Filed: December 3, 1976
    Date of Patent: October 17, 1978
    Assignee: Xerox Corporation
    Inventor: David D. Thornburg
  • Patent number: 4118112
    Abstract: A tapered resistor device which includes generally a tapered resistive film comprising a semiconducting material or other suitable material with a negative temperature coefficient of resistivity is provided. It is apparent with reference to the curves which show the variation of .DELTA.E that large energy savings are possible at the narrow end of the taper with relatively small concomitant degradation in the temperature profile of the region of interest. It is therefore seen that employing a material with a negative temperature coefficient of resistivity provides an improvement in reducing power usage according to the principles of the instant invention.
    Type: Grant
    Filed: December 3, 1976
    Date of Patent: October 3, 1978
    Assignee: Xerox Corporation
    Inventor: David D. Thornburg
  • Patent number: 4104515
    Abstract: A consumable credit card is provided which comprises a recording device that is adapted to receive progressively advancing recording up to a limit at which time the card is consumed and thereafter is discarded. The card is adapted to be inserted into a reader which accepts, reads and advances the indication on the credit card or reading to indicate an additional use until the credit card is expended and the reader no longer allows the item or service to be dispensed because the credit card has been expended. This credit card employs tapered resistor technology in order to store a permanent record of expended credit and advance same upon energization of the tapered resistor element residing in the device. Methods of employing this device in billing systems are also disclosed.
    Type: Grant
    Filed: December 3, 1976
    Date of Patent: August 1, 1978
    Assignee: Xerox Corporation
    Inventors: David D. Thornburg, Roy J. Lahr
  • Patent number: 4099071
    Abstract: A tapered resistor heating element is provided which sequentially heats and actuates in a controlled fashion heat sensitive media. In one embodiment a tapered resistor heating element sequentially heats in a controlled fashion heat sensitive switches. Heat sensitive resistors and heat sensitive threshold switches may also be employed in this configuration. This system may be utilized as a meter relay or as described in another embodiment as a scanner. Novel exclusive OR gates are also disclosed which are employed in one embodiment of the scanner of the instant invention.BACKGROUND OF THE INVENTIONThis invention relates generally to scanning devices and more specifically to monolithic electronic scanning devices.It is known that a major problem with matrix addressed displays and the like is the requirement for numerous connections in their implementation between the matrix elements and the ancillary addressing and driving devices. For instance, a display panel with 10.sup.6 matrix elements requires about 2.
    Type: Grant
    Filed: December 3, 1976
    Date of Patent: July 4, 1978
    Assignee: Xerox Corporation
    Inventor: David D. Thornburg
  • Patent number: D262294
    Type: Grant
    Filed: June 6, 1979
    Date of Patent: December 15, 1981
    Assignee: Xerox Corporation
    Inventor: David D. Thornburg