Northrop Grumman Systems Corporation

United Technologies Corporation

US Government As Represented by the Secretary of the Army

Norhtrop Grumman Corporation

Thomas J Rebeschi

Mohan L Kapoor

Russell A Budzilek

Edward L Young

Dominic L Monarchie

Thomas J Ray

Dominick L Monarchie

Daniel J Toffolo

Peter O Shanaghan

Pixel luminance of an electroluminescent display panel is controlled by a row driver applying a voltage equal to the panel's threshold voltage, and column drivers applying the voltage value above the threshold voltage to bring the pixel to the desired luminance. Each column driver independently samples a stepped ramp voltage signal at its own predetermined time selected as a function of the desired luminance. Each column driver then holds the sampled voltage value, and applies to its corresponding column electrode at the appropriate time a voltage equal to the sampled voltage value. The voltage rate of change of each individual step of the stepped ramped voltage signal can be controlled to vary the luminance levels, and to uniformly separate each of the luminance levels.

Gray-scale stepped ramp generator with individual step correction

A relatively low cost, portable, low complexity, low power helmet mounted display using an electroluminescent display and associated drive circuitry configured and interconnected to take advantage of our ability to provide a -180 V and +240 V output to a row driver from a single -180 V and an already existing +60 V Supply, thus eliminating size, weight and expense of supplying a separate 240 V power supply. The +60 V power supply is already supplying the +60 V to the column driver circuitry. Also included is a column driver with a direct analog interface with an input buffer, the buffer including a polarity inverter and an adder for selectively inverting the external analog signal and adding a DC voltage.

High performance, low cost helmet mounted display

A method and apparatus for providing a driver circuit for an electroluminescent display panel comprising a row driver including positive row drive elements and negative row drive elements, a first power lead with a first predetermined voltage V.sub.neg connected in series through a first switch connection to a first node, the first node connected to a first current limiter to the negative row drive elements, a second current limiter operably connected between a first fixed potential to a second node, the second node connected to the positive row drive elements, a third current limiter connected between the negative row drive element and the second fixed potential, a second power lead with a second predetermined voltage V.sub.pos connected in parallel to the first node through a second switch connection and a power storage device connected between the first and second nodes, wherein the voltage across the positive and negative row drive elements is selectable, via predetermined operation of the first and second switch connections, between a) V.sub.neg and b) the difference between V.sub.pos and V.sub.neg.

Symmetric row drive for an electroluminescent display

A thin film electroluminescent display panel is driven with either a symmetric or asymmetric drive scheme which includes at least one equalizing voltage pulse per write cycle to remove carriers trapped at the interfaces of dielectric layers and phosphor layer in order to stabilize the charge of each display panel pixel. The present invention reduces the smearing, latent image and pseudo persistence problems caused by carriers being retained and accumulated at the dielectric and phosphor layer interfaces.

Increased brightness drive system for an electroluminescent display panel

A method and apparatus for providing a column driver circuit for an electroluminescent display panel including a column driver with a column driver including a direct analog interface with an input buffer with an input for accepting an external analog signal and an output for outputting an analog signal for said electroluminescent display panel. The buffer includes a polarity inverter and an adder for selectively inverting the external analog signal and adding a DC voltage. The column driver further includes an output demultiplexer, a plurality of sample and hold circuits, and an output driver employing negative feedback techniques for comparing the feedback signal to a preselected external variable voltage and selecting the appropriate drive signal.

Analog video input flat panel display interface

A power supply for providing a symmetric drive for an AC electroluminescent (EL) display panel includes a single power supply which provides two voltage signal values of opposite polarity V.sub.pos,V.sub.neg to the panel's row drivers. The supply also corrects the difference between the two voltage signal values V.sub.pos,V.sub.neg as a function of the difference between the maximum column driver voltage value V.sub.col and its nominal value to reduce latent images on the display panel. By utilizing a single switching regulator to generate the opposite polarity row voltages V.sub.pos,V.sub.neg the circuit complexity and cost associated with providing a symmetric drive for an EL panel is reduced.

Symmetric drive for an electroluminscent display panel

The luminosity of electroluminescent display pixels arranged at intersection regions between row and column electrodes is controlled so as to compensate for the effect of interelectrode coupling by reducing the voltage differentials applied between the row electrode being addressed and the column electrodes relative to those coresponding to initial pixel luminosity data contained in an incoming data stream, as a direct function of total row luminosity information extracted from that segment of the incoming data stream which pertains to the respective row.

Electroluminescent display brightness compensation

Circuitry for selectively sustaining a gaseous discharge display panel to splay selected information which circuitry permits the use of a single power supply.

Sustainer circuit for plasma display panels

A cathode ray tube employing magnetic deflection coils for deflecting the electron beam in the horizontal and vertical directions, is corrected for the astigmatism error created by the non-uniform magnetic deflection field which causes a predictable elliptical distortion of the electron beam, through the use of two sets of correction coils mounted on a common annular magnetic core located on the neck of the CRT, which distorts the electron beam prior to its entry into the magnetic deflection field in a manner that is complementary to the distortion created by the non-uniform magnetic deflection field. The excitation currents for the correction coils are derived from the horizontal (Vx) and vertical (Vy) beam deflection voltage signals, in such a manner that the excitation current for the first correction coil is proportional to Vx.sup.2 - Vy.sup.2, and the excitation for the second correction coil is proportional to 2.sup.. Vx.sup.. Vy.

Growing community of inventors

North Haven, CT, United States of America

Thomas J Rebeschi