Hisashi Uede 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).
Abstract: In a display device such as a thin-film EL display device, etc. formed with a dielectric layer disposed between a plurality of scanning side electrodes and a plurality of data side electrodes in the direction for them intersecting to each other, a modulation voltage, varied according to gradation display data is applied to the data side electrodes, and a positive or negative writing voltage is applied to the scanning side electrodes in a line order for a gradation display different in brightness. Binary coded signals corresponding to each gradation of a gradation display are used as the gradation display data. The logical value of the binary coded signal is inverted according to the polarity of the writing voltage. Thus, a common gradation display can be performed from one binary coded signal for both the negative driving that applies a negative writing voltage and the positive driving that applies a positive writing voltage.
Abstract: A display device, such as thin film EL display device, is formed by interposing a dielectric layer between a plurality of scanning electrodes and a plurality of data electrodes which are arranged at right angles. Modulation voltage is varied in accordance to the display data, and is applied to the data electrodes. Further, a writing voltage is applied to the scanning electrodes in sequential line order, to thereby perform gradation display. Further, the writing voltage includes a ramp voltage, which varies with time. Thus, the peak of the current flowing through the luminescent layer of the picture element, as a current contributing to the luminescence, is suppressed to a low level. contributing to the luminescence, is suppressed to a low level. Accordingly, the energization period of the current is also elongated. Thus gradation display over multiple levels is made possible and a stable display of different gradation levels is enabled.
Abstract: This invention relates to gradation display by a pulse width control method (PWM method) in every pixel in a capacitive display apparatus such as a liquid crystal display apparatus. The driving voltage applied to the electrodes is varied slowly, and the number of gradations of gradation display by the PWM method is increased. Since the capacitive display apparatus is used, for each electrode further from the drive circuit, the driving pulse is more influenced and its persisting duration is extended. As a result, even in identical gradation data, uneven colors may occur. The pulse width applied to the electrodes is gradually decreased as scanning of the electrodes sequentially occurs. Therefore, the brightness of the capacitive display apparatus may be made uniform over the entire screen surface.
Abstract: In accordance with the invention, gradation display is performed for each picture element in capacitive display apparatuses such as EL display apparatus by means of pulse width modulation. In doing so, pulse duration of the voltage applied to one group of electrodes among the a plurality of electrodes arranged in matrix is so set as to span over two scanning periods, during which another group of electrodes which are grouped into pairs each of two adjacent lines are scanned successively. This reduces the number of drive voltage charge and discharge cycles. Consequently power consumption of the display apparatus of PWM system can be controlled to a low level.
Abstract: A method of driving a display device with a plurality of scanning side electrodes and a plurality of data side electrodes which are disposed in directions intersecting each other, and a dielectric layer interposed between the scanning side electrodes and the data side electrodes, and including steps of applying modulation voltages corresponding to display data to the data side electrodes, and also applying writing voltages of positive or negative polarity to the scanning side electrodes through line sequence, so as to cause picture elements composed of the dielectric layer to emit light. The driving method further includes steps of thinning out the display data, and applying a plurality of kinds of modulation voltages different in amplitude according to each frame, so as to cause the picture elements to effect gradation display of different brightness in multi-stages.
Abstract: A wiring circuit substrate comprises first circuit element means one one side of the substrate connected to electrode lines of X-Y matrix electrodes, respectively, and second circuit element means in the symmetrical position of the first circuit element means on the other side of the substrate connected to the electrode lines of the X-Y matrix electrodes, respectively, wherein each of leads of the first and the second circuit element means is connected to the output and input lines of the X-Y matrix electrodes via through holes, respectively.The first circuit element comprises integrated transisitors for driving the X-Y matrix electrodes. The second circuit element comprises integrated diodes for protecting an overcurrent in the X-Y matrix electrodes.
Abstract: A thin film EL display panel is composed of an EL layer placed between scanning electrodes and data side electrodes which are arranged at right angles to the scanning electrodes. A thin film EL display panel drive circuit includes a first and a second switching circuits connected to each of the scanning electrodes to apply voltages of negative and positive polarities, respectively, with respect to the voltage of the data side electrodes; and third and a fourth switching circuits connected to each of the data side electrodes to respectively charge and discharge the EL layer corresponding to the scanning electrode.
Abstract: A driving method of a thin film EL display unit and a driving circuit thereof comprising a thin film EL panel constituted by installing an EL layer between scanning-side electrodes and data-side electrodes and driver ICs which are connected respectively to the scanning-side electrodes and the data-side electrodes, wherein, on a drive which applies a write voltage positive to the data-side electrodes to the scanning-side electrodes, the scanning-side electrodes are raised once to a predetermined potential or higher, and thereafter the positive write voltage is applied thereto, and on a drive which applies a write voltage negative to the data-side electrodes to the scanning-side electrodes, the scanning-side electrodes are reduced once to a predetermined potential or lower, and thereafter the negative write voltage is applied thereto, which can reduce a maximum voltage applied to the scanning-side driver ICs.
Abstract: A thin film electroluminescent (EL) display panel drive circuit includes first and second switching circuits for driving scanning electrodes of the panel in two fields, wherein odd numbered scanning electrodes are applied with a negative voltage polarity and even numbered scanning electrodes are provided with a positive voltage polarity in a first field, and the voltage polarities are reversed during the second field. Data signals are applied to data electrodes by a data electrode driver circuit which includes third and fourth switching circuits for providing selected data electrodes with a modulate voltage of a stepwise nature or ground, depending upon whether the selected data electrodes intersect with selected scanning electrodes having a negative or positive voltage polarity respectively. The stepwise modulation voltage is supplied by a control switching circuit which selectively supplies the third switching circuit with voltages of a first level, a second level and a floating level.
Abstract: A driving method is described for thin film EL display devices having an EL layer interposed between scanning side electrodes and data side electrodes which are intersected to each other. The method comprises displaying frames formed by a line sequential drive in which voltage corresponding to display data is applied to the data side electrodes. Concurrently, write pulses which are negative and positive with respect to the data side electrodes are applied to the scanning side electrodes. Further the write pulses which are positive or negative with respect to the data side electrodes are applied to the scanning electrodes. The number of light emitting picture elements of the scanning side electrodes is previously detected from display data and the width of the write pulses, which are at least one of positive or negative is controlled in proportion to the number of the light emitting picture elements. Thus, the brightness of the light emitting picture elements is uniform due to the driving circuit thereof.
Abstract: An aging drive method for a thin film EL panel includes the performing a preparatory step of short-circuiting all transparent electrodes by a first connecting line, short-circuiting every other metal electrodes by a second connecting line and short-circuiting the other metal electrodes by a third connecting line. Thereafter four fields are repeatedly periodically executed for a specified period of time to thereby cause all picture elements of the panel to luminesce for aging. Each of the four fields includes a first step of applying a first voltage across the first and second connecting lines and across the first and third connecting lines to charge all the picture elements. Further a second step is included of applying a second voltage across the second and third connecting lines while holding the transparent electrodes in a floating state.
Abstract: When driving a thin-film EL display panel having groups of two electrodes on opposing sides of a thin-film EL layer, a voltage is applied so that the polarity of the AC pulse applied to the intersection (picture element) of opposing electrodes is the reverse of the polarity of the AC pulse applied simultaneously or nearly simultaneously to adjacent or nearly adjacent picture elements. This drive method avoids flicker caused by differing luminance intensities resulting from alternating polarity in EL matrix-type displays.
Abstract: The preferred embodiment discloses a new thin-film EL display panel drive circuit using EL layers installed between the scan-side electrodes and the data-side electrodes aligned so as to allow them to cross one another, comprising: scan-side electrodes connected to the drain terminal of the N-ch high-voltage resistant driver having a grounded source terminal and also connected to the other drain terminal of the P-ch high-voltage resistant driver having a source terminal connected to the pull-up charge drive circuit and to the write drive circuit via the scan-side common bus line; and data-side electrodes connected to the drain terminal of the N-ch high-voltage resistant driver having a grounded source terminal and also having the anode common terminal connected to the cathode terminal of the diode array connected to the preliminary charge drive circuit via the data-side common bus line.
Abstract: A drive circuit for a thin-film electroluminescent (EL) matrix display panel includes an odd side N-ch high voltage MOS driver, and an odd side P-ch high voltage MOS driver connected to odd number scanning electrodes of the thin-film electroluminescent (EL) matrix display panel. Even number scanning electrodes of the thin-film electroluminescent (EL) matrix display panel are connected to an even side N-ch high voltage MOS driver and an even side P-ch high voltage MOS driver. The four MOS drivers are effectively controlled to perform an alternating current driving of the thin-film electroluminescent (EL) matrix display panel.
Abstract: A thin-film EL element is manufactured by forming a silicon nitride or silicon oxynitride film for a first dielectric layer by sputtering and a silicon nitride or silicon oxynitride film for a second dielectric layer by plasma chemical vapor deposition so that the element's resistance against moisture and mass productivity can be improved.
Abstract: A drive circuit for a thin-film electroluminescent (EL) matrix display panel includes an odd side N-ch high voltage MOS driver, and an odd side P-ch high voltage MOS driver connected to odd number scanning electrodes of the thin-film electroluminescent (EL) matrix display panel. Even number scanning electrodes of the thin-film electroluminescent (EL) matrix display panel are connected to an even side N-ch high voltage MOS driver and an even side P-ch high voltage MOS driver. The four MOS drivers are effectively controlled to perform an alternating current driving of the thin-film electroluminescent (EL) matrix display panel. A source level switching circuit is connected to the odd side and even side N-ch high voltage MOS drivers so as to switch the source voltage in synchronization with the field driving of the thin-film electroluminescent (EL) matrix display panel.
Abstract: A method of aging a thin-film electroluminescent (EL) display element comprises the steps of applying an aging voltage to electrodes of the element, and changing the peak value of the aging voltage in accordance with the characteristics of the element which change during an aging period. An aging circuit to perform the above method is provided. In a specific example, the magnitude of the aging voltage is changed according to the relationship between the brightness of electroluminescence generated from the element and a driving voltage applied to the element. In another specific example, the magnitude of the aging voltage is changed such that the brightness of the electroluminescence is sustained to be substantially constant, thereby making operation points constant on the above characteristics.
Abstract: A thin film EL element has a glass substrate, a pair of electrode layers formed on this glass substrate, and an electroluminescent layer sandwiched between these electrode layers. The glass substrate is of non-alkali type and has volume resistivity of 10.sup.6 ohm-cm or greater at 600.degree. C., alkali content of 0.5 wt % or less, and strain point of 600.degree. C. or higher.