Sharp Kabushiki Kaisha Corporation

Chuji Suzuki

Masahiro Ise

Yoshiharu Kanatani

Etsuo Mizukami

Katsuyuki Machino

Kenzo Inazaki

Toshihiro Ohba

Noritoshi Kako

Yasukuni Yamane

Yoshiki Nishioka

Shuhei Yasuda

Syoichi Yasuda

Kenzoo Inazaki

Kenzoh Inazaki

A flat panel television receiver implemented with a thin-film electroluminescent panel allows viewer's selection of a normal moving picture and a steady picture mode which resorts to the inherent hysteresis properties of the EL panel. A write field interval and an erase field interval are assigned alternatively with respect to each other.

Flat panel television receiver implemented with a thin film EL panel

Between adjacent matrix type electrodes in a thin-film EL display panel, one of which is transparent, there is disposed an EL layer sandwiched by a pair of dielectric layers, which manifests a hysteresis curve when plotted with respect to the applied voltage vs light intensity characteristics. The thin-film EL display panel is further provided with at least one reference electrode. In reading out the memory state of the display panel, current is derived which has an amplitude equal to the difference between the current drawn through the reference electrode and the readout current.

Readout scheme of a matrix type thin-film EL display panel

For a thin-film EL display panel which exhibits the hysteresis loop phenomenon in the applied voltage versus brightness relationship, a string of alternating sustain pulses are applied, the amplitude of which is chosen at the voltage level appearing at the point in the hysteresis loop characteristics where the difference between the minimum light brightness on the voltage increasing curve and the maximum light brightness on the voltage decreasing curve is substantially a maximum. A flash lamp, for example, a xenon lamp which releases light beams toward the thin-film EL display panel, is energized in synchronism with the application period and pause period of the alternating sustain pulses. There are provided means for controlling the application period of the alternating sustain pulses and the illumination period of the flash lamp in accordance with the light activated write mode or erase mode. The light beams can be applied to the thin-film EL display panel via a film bearing an optical image to be written or erased.

Thin-film EL display panel with light-activated write and erase means

An EL display panel comprises an electroluminescent element made of, for example, a ZnS:Mn layer sandwiched between a pair of dielectric layers. A front electrode is formed on one of the dielectric layers, and a rear electrode is formed on the other dielectric layer in order to apply a voltage signal across the electroluminescent element. An electron beam is applied to the electroluminescent element through the rear electrode to provide the electroluminescence at the position to which the electron beam is applied. A desired pattern is displayed on the EL display panel by properly controlling the application of the electron beam.

EL Display drive controlled by an electron beam

In pattern recognition systems for determining and recognizing any normalized characters registered in a record medium by means of a character characteristic extractor, the presence and absence of two-dimensional intelligence signals contained within the normalized characters to be recognized is determined by the consecutive scanning by only a single vertical array of light-sensitive elements, while the record medium travels horizontally with respect to said vertical array. Multiple intelligence signals for the vertical segments of each vertical scanning developing across the respective elements are combined together in a signal compression mode and then introduced into a pattern decoding matrix in order to extract the character characteristic or pattern based upon a combination of the compressed intelligence signals.

Pattern recognition systems

A coil is serially connected to a capacitive display unit, such as an EL display panel, which includes an insulating display element sandwiched between a pair of electrodes. The coil and the electrostatic capacitance of the display unit function, in combination, to form an LC resonance circuit, which limits transient current flowing through the insulating display element and enables the display unit to operate in a low power dissipation mode. An alternating driving signal to be applied to the display unit has an intermediate potential period on which a writing pulse is superimposed, thereby to minimize high voltage requirement of the writing circuit.

Control system for driving a capacitive display unit such as an EL

Disclosed is a driving method for a thin-film electroluminescent element of a three-layer construction which emits light and exhibits the hysteresis phenomenon within the light emission versus applied voltage characteristics. The light intensity is maintained and memorized at a predetermined value in the element by the application of a train of sustaining pulses of alternating voltage, the amplitude thereof being chosen at the voltage level appearing at the point in the hysteresis loop characteristics where the difference between the maximum light brightness on the voltage decreasing curve and the minimum light brightness on the voltage increasing curve is considerably large. The sustaining light brightness is controlled by varying the amplitude or the pulse width of the sustaining pulses. The information may be written, memorized and eliminated in the EL element as variations of the light brightness. To write or eliminate the information in the EL element, it is also effective to utilize external light excitation.

Driving method for a thin-film electroluminescent element of a

The present disclosure is directed toward a drive method and circuit for a memory matrix panel which comprises a light-emitting body having hysteresis behavior responsive to application of a desired AC voltage, a plurality of horizontal electrodes disposed on a first major surface of the light-emitting body and a plurality of vertical electrodes disposed on a second major surface of the light-emitting body, each cross point of the both electrodes providing a light-emitting unit point in a matrix array. A period of the applied AC voltage includes at least three sections wherein, prior to the writing, erasing or reading of information, a horizontal maintenance pulse having an amplitude necessary to maintain light emittance is applied to the plurality of horizontal electrodes during the first section thereof and a vertical maintenance pulse having an amplitude necessary to maintain light emittance is applied to the vertical electrodes during the second section thereof. In order to perform the writing, erasing or reading of information on a selected cross point, the vertical (or horizontal) electrode associated with such point receives an enable pulse having the shape identical with that of the horizontal maintenance pulse but the phase shifted into the third section, whereas the associated horizontal (or vertical) electrode receives write, erase or read out each having a predetermined amplitude necessary to perform the write, erase or read operation, the respective amplitude being superimposed on the enable pulse.

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Nara, Japan

Chuji Suzuki