Planar Systems, Inc.

Other

University of California

Christopher N King

Richard T Tuenge

Richard E Coovert

Sey-Shing Sun

William A Barrow

Iranpour Khormaei

James G Kane

Eric R Dickey

Paul Howard Holloway

David C Smith

Robert C Dye

Terrance S Larsson

Robert T Flegal

P Niel Yocom

Steven F Wald

Brian J Dolinar

Ronald O Petersen

Monte Rhoads

Laurin G Blacken

Philip D Rack

Christian F Schaus

Brad Aitchison

Paul E Gulick

A full color active matrix electroluminescent display includes an active matrix of pixel electrodes, a broad spectrum electroluminescent phosphor stack placed atop the active matrix of pixel electrodes and a transparent electrode placed atop the electroluminescent phosphor stack. A liquid crystal color shutter device is placed atop the transparent electrode for selectively filtering light from the electroluminescent phosphor stack selectively permitting the transmission of red, green or blue colored light in response to commands from a synchronizing circuit that synchronizes the operation of the shutter with the illumination of selected pixels in the active matrix display. Performance is further enhanced by the use of a double notch filter for the white light emitting broad spectrum electroluminescent phosphor so as to provide it with a uniform response at all waves lengths of interest.

Field sequential color AMEL display

An active matrix electroluminescent device that includes a plurality of layers. A rearwardly disposed support layer supports the plurality of layers and an interface circuit. The interface circuit is electrically connected to row and column drivers by a plurality of first electrical lines. The drivers are electrically connected to the plurality of layers so as to enable pixels within the electroluminescent device to be selected. An interface controller is remotely located from the support layer and is electrically connected to the interface circuit by at least one second electrical line so as to indicate which pixels within the device to illuminate. The number of first electrical lines is greater than the number of the at least one second electrical line. In another embodiment of the present invention, the number of lines required to interconnect a passive thin film electroluminescent device with an interface controller can in a similar manner be reduced by including an interface circuit.

Substrate carriers for electroluminescent displays

A crystalline blue emitting thiogallate phosphor of the formula RGa.sub.2 S.sub.4 :Ce.sub.x where R is selected from the group consisting of calcium, strontium, barium and zinc, and x is from about 1 to 10 atomic percent, the phosphor characterized as having a crystalline microstructure on the size order of from about 100 .ANG. to about 10,000 .ANG. is provided together with a process of preparing a crystalline blue emitting thiogallate phosphor by depositing on a substrate by CVD and resultant thin film electroluminescent devices including a layer of such deposited phosphor on an ordinary glass substrate.

Blue light emitting thiogallate phosphor

A method of illuminating an active matrix EL device (AMEL) to provide a gray scale display. The device comprises a first electrode layer comprising an active matrix of individually adjustable pixel electrodes, a second electrode layer, and a thin film EL laminate stack including at least an EL phosphor layer and a dielectric layer, and the stack being disposed between the first and second electrode layers. The gray scale display is illuminated by the steps of, energizing a first set of selected ones of the pixel electrodes with data signals during a first subframe time period. Selected pixels are illuminated by driving the second electrode layer during the first subframe time period a first illuminating signal having predetermined characteristics including frequency, amplitude, wave shape and time duration. Thereafter, a second set of selected ones of the pixel electrodes are energized with data signals during a next subframe time period. Selected pixels are again illuminated during the next time period with an altered illumination applied to the second electrode signal wherein one or more of the predetermined characteristics differ from the first illuminating signal.

Time multiplexed gray scale approach

A TFEL structure is disclosed that includes first and second electrode layers sandwiching a TFEL stack including at least one insulator layer and a novel three layer laminate structure. The three-layer laminate structure includes an alkaline earth thiogallate phosphor layer, a nucleating layer and an injection layer. The nucleating layer lies between the phosphor layer and the injection layer. The injection layer provides a charge injection function through the nucleating layer for the thiogallate phosphor layer which is of high crystallinity at its interface with the nucleating layer. A preferred injection layer includes indium, for example as the metal or as indium tin oxide. The best material for the nucleating layer is zinc sulfide.

TFEL device with injection layer

An AC TFEL device includes a front electrode set deposited on a transparent substrate and a rear electrode set, the electrode sets enclosing a thin film laminate which includes a pair of insulating layers sandwiching an alkaline earth thiogallate thin film phosphor doped with a rare earth activator. The thiogallate phosphor layer is capable of producing blue light of sufficient intensity to create a full color TFEL panel.

AC TFEL device having blue light emitting thiogallate phosphor

A TFEL device for producing a high brightness output comprises a substrate supporting a laminar thin film stack including a front electrode layer and a rear electrode layer sandwiching an electroluminescent laminate comprising an electroluminescent layer sandwiched by a pair of insulating layers. A thin film insulating layer is grown by evaporation on the glass substrate and produces a surface having a degree of roughness which is replicated by the remaining thin film layers. The surface contour at the interfaces between each of the thin film layers is convoluted which reduces internal light reflection and provides more light output at the front of the panel.

High brightness TFEL device and method of making same

An electrode configuration for reducing contact density in matrix-addressed display panels includes a first set of electrodes having termination points for connection to external driving electronics situated near the edge of a supporting substrate, and a second set of electrodes alternately interleaved among said first set having termination points spaced inwardly from the substrate's edge. An insulating film covers the termination points of the second plurality of electrodes and bond pads placed atop the insulating film are connected to the electrodes by leads. This insulates the second plurality of electrodes from a possible short circuit caused by random or one-on-one interconnects that bridge areas in the gaps between the electrodes.

Electrode configuration for reducing contact density in matrix-addressed

A TFEL device having improved contrast includes a laminate having a phosphor layer sandwiched between front and rear insulating layers placed upon a substrate supporting a set of front transparent electrodes. The rear set of electrodes are transparent or semitransparent so as not to reflect ambient light toward the viewer. The TFEL laminate is contained within a cavity created by an enclosure secured to the substrate by an adhesive. Darkly dyed filler material is injected into the cavity whose rear inside wall may have a dark coating. The semitransparent electrodes may be made of gold or may be made of transparent indium tin oxide having narrow aluminum bus bars for improved conductivity.

Thin film electroluminescent display with improved contrast

A highly efficient, AC-excited, blue light-emitting phosphor for solid-state thin-film electro-luminescent (TFEL) devices is comprised of strontium sulphide (SrS) host material doped with cerium fluoride (CeF.sub.3) acting as an emitter providing a source of photons. The blue SrS:CeF.sub.3 phosphor is about one hundred times brighter than the brightest zinc sulphide/thulium fluoride (ZnS:TmF.sub.3) blue phosphor heretofore known. To increase brightness level, at some loss of energy efficiency, electron-injection layers of zinc sulfide (ZnS) are placed on either side of the SrS:CeF.sub.3 layer in the TFEL device.

Thin-film electroluminescent device

A TFEL panel includes orthogonally disposed sets of scanning and data electrodes. The scanning electrodes are strobed with a preconditioning voltage and data is provided to selected data electrodes simultaneously with the line by line strobing of the scanning electrodes. A refresh pulse is applied to the screen once per frame of data at times which vary from frame to frame. This may be accomplished either by varying the time of occurrence of the refresh pulse within each frame or by holding the time of occurrence of the refresh pulse constant and varying the strobing sequence of the scanning electrodes. This technique prevents certain portions of the screen from generating a latent image due to charge accumulation which would otherwise result from the timing asymmetry between the scanning of certain electrodes and the fixed timing of the refresh pulse.

Growing community of inventors

Portland, OR, United States of America

Christopher N King