Having Compensating Pulse Patents (Class 345/78)
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Patent number: 8031142Abstract: A circuit for EL panel DC offset correction is provided. The circuit includes components such as an EL panel driver, an error circuit, a pulse width modulation circuit, and a low-pass filter. The low-pass filter performs low-pass filtering on the voltage across the EL panel to provide a low-pass filter output signal. Further, the error circuit receives the low-pass filter output signal and a reference signal, and provides an error signal. The DC bias across the EL panel is adjusted based, at least in part, on the error signal. In this way, DC offset correction is provided based on the negative feedback.Type: GrantFiled: September 14, 2006Date of Patent: October 4, 2011Assignee: National Semiconductor CorporationInventor: Jeffrey Doyle Mullin
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Patent number: 8026874Abstract: In a display apparatus including a correction unit and a switching transistor, the correction unit operates in a non-light emission period such that a correction voltage for eliminating an effect of a variation in a characteristic of a driving transistor is stored in a storage capacitor. The switching transistor is disposed between one current terminal of the driving transistor and a light emitting element. The switching transistor turns off during the non-light emission period thereby to electrically disconnect the light emitting element from the one current terminal of the driving transistor thereby preventing a leakage current from flowing through the light emitting element during the period in which the correction unit operates, and thus preventing the correction voltage from having an error due to the leakage current.Type: GrantFiled: December 22, 2010Date of Patent: September 27, 2011Assignee: Sony CorporationInventors: Junichi Yamashita, Masatsugu Tomida, Katsuhide Uchino
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Patent number: 8026876Abstract: A system and method are disclosed for determining a pixel capacitance. The pixel capacitance is correlated to a pixel age to determine a current correction factor used for compensating the pixel drive current to account for luminance degradation of the pixel that results from the pixel aging.Type: GrantFiled: August 15, 2007Date of Patent: September 27, 2011Assignee: Ignis Innovation Inc.Inventors: Arokia Nathan, G. Reza Chaji
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Patent number: 8018425Abstract: A driving apparatus of a light emitting diode and a liquid crystal display are disclosed. The driving apparatus of a LED includes a plurality of LED groups in which LEDs are connected in series to each other; a plurality of constant voltage supply units that supplies a constant voltage required to drive a constant current to each of the plurality of LED groups and that outputs the constant voltage in which an output voltage is equal to or lower than an input voltage; and a pulse width modulation signal supply unit that supplies a pulse width modulation signal to each of the constant voltage supply units.Type: GrantFiled: December 15, 2006Date of Patent: September 13, 2011Assignee: LG Display Co., Ltd.Inventors: Eui Yeol Oh, Haang Rhym Chu
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Publication number: 20110216056Abstract: An organic light emitting diode display that includes pixels having organic light emitting diodes and driving transistors for supplying a driving current to the respective organic light emitting diodes. Also included is a compensator for receiving a predetermined voltage applied to a gate electrode of the respective driving transistors, finding a threshold voltage, mobility, and a change of mobility of the driving transistors, and determining a compensation amount caused by an input image data signal while sinking a predetermined current to a path of a driving current to the organic light emitting diode through a data line connected to the pixels. Further included is a timing controller for receiving the compensation amount, correcting the input image data signal, and transmitting the corrected image data signal and a data driver for generating a data voltage based on the corrected image data signal, and supplying the data voltage to the pixels.Type: ApplicationFiled: September 22, 2010Publication date: September 8, 2011Applicant: SAMSUNG MOBILE DISPLAY CO., LTD.Inventors: Myoung-Hwan YOO, Choon-Yul OH
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Patent number: 8009125Abstract: In an organic electroluminescent (EL) display device, a main display panel and a sub display panel share a data line and a power supply voltage line. The organic EL display device has a top emission type main display panel and a bottom emission type sub display panel in a single display panel. The main display panel is composed of main pixels, each having a compensation circuit for compensating a threshold voltage, and the sub pixel display is composed of basic sub pixels without any compensation circuit. Each of the sub pixels has a boost capacitor which increases a data voltage, and which is disposed between a scan line and a storage capacitor so as to use the same voltage and power supply voltage as the main pixels. The sub pixels having the boost capacitor are disposed in the sub display panel, so that the main and sub display panels share the data line and the power supply voltage line.Type: GrantFiled: September 29, 2006Date of Patent: August 30, 2011Assignee: Samsung Mobile Display Co., Ltd.Inventor: Yang-Wan Kim
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Patent number: 8009129Abstract: During a blanking period of a video signal, an element driving transistor for controlling a drive current supplied to an EL element is operated in its saturation region to thereby set the EL element to an emission level, and a current flowing through the EL element at that time is detected. Each current detector includes a current detection amplifier and a successive approximation type AD converter, and a DA converter of the successive approximation type AD converter is commonly shared among a plurality of the AD converters. With this arrangement, sufficient AD converting speed can be attained while using a simple structure to execute current detection for correcting display variations.Type: GrantFiled: March 31, 2008Date of Patent: August 30, 2011Assignee: Semiconductor Components Industries, LLCInventors: Yuichi Matsuo, Takashi Ogawa
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Patent number: 8004479Abstract: A method of compensating for changes in the characteristics of transistors and EL devices in an EL display, includes providing an EL display having a two-dimensional array of EL devices arranged in rows and columns, wherein each EL device is driven by a drive circuit in response to a drive signal; providing a first drive circuit for an EL device having three transistors and providing a second drive circuit for an EL device having only two transistors, and wherein a first column in the display includes at least one first drive circuit and an adjacent second column includes at least one second drive circuit; deriving a correction signal based on the characteristics of a transistor in a first drive circuit, or the EL device; and using the correction signal to adjust the drive signals applied to the first drive circuit and one or more adjacent second drive circuits.Type: GrantFiled: November 28, 2007Date of Patent: August 23, 2011Assignee: Global OLED Technology LLCInventors: Christopher J. White, Charles I. Levey, Michael E. Miller, Felipe A. Leon
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Patent number: 7995013Abstract: In a display apparatus, as shown in FIG. 1, by using a reference signal, a shift register and a logical operation circuit generate a driving signal in periods for correcting a threshold voltage based on a rectangular wave signal. Also by using the reference signal, a write signal in a mobility correcting period is generated by an inverter, a NAND circuit, a level conversion circuit, a buffer circuit, a driving power generating unit, and a low-pass filter including a resistor and a capacitor. The signals are separately generated and are selectively output. Thus, excessive or insufficient mobility correction based on emission brightness can be prevented.Type: GrantFiled: February 22, 2008Date of Patent: August 9, 2011Assignee: Sony CorporationInventors: Yutaka Mitomi, Yukihito Iida, Takao Tanikame, Katsuhide Uchino
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Pixel circuit, display device, driving method of pixel circuit, and driving method of display device
Publication number: 20110169812Abstract: A pixel circuit, disposed at a part where a scanning line and a signal line intersect each other, includes at least an electrooptic element, a drive transistor, a sampling transistor, and a retaining capacitance. The drive transistor has a gate connected to an input node, a source connected to an output node, and a drain connected to a predetermined power supply potential and supplies a driving current to the electrooptic element according to a signal potential retained in the retaining capacitance. The electrooptic element has one terminal connected to the output node and another terminal connected to a predetermined potential. The sampling transistor is connected between the input node and the signal line and operates when selected by the scanning line, samples an input signal from the signal line, and retains the input signal in the retaining capacitance. The retaining capacitance is connected to the input node.Type: ApplicationFiled: February 18, 2011Publication date: July 14, 2011Applicant: Sony CorporationInventors: Katsuhide Uchino, Junichi Yamashita -
Patent number: 7973746Abstract: A pixel includes a light emitting diode, and a switching circuit that is coupled to a data line and a compensation power source line, and includes a transistor including a control terminal, a first main terminal coupled to a power source line, and a second main terminal coupled to the light emitting diode. The switching circuit generates a control signal based on at least a voltage of a data signal transmitted through the data.Type: GrantFiled: June 25, 2008Date of Patent: July 5, 2011Assignee: Samsung Mobile Display Co., Ltd.Inventors: Sam-Il Han, Jin-Tae Jeong
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Patent number: 7973747Abstract: There is provided a display device: a display unit including a plurality of scan electrodes arranged to extend in parallel to each other along a first direction, a plurality of data electrodes arranged to extend in parallel to each other along a second direction crossing the scan electrodes, and a plurality of pixels, each pixel at which a pair of the scan electrode and the data electrode cross each other, each pixel having a light emitting layer and a dielectric layer interposed between the scan electrode and the data electrode from a direction vertical to a face; and an erasing pulse supplying unit operable to supply attenuation voltage pulse, to the light emitting layer of each pixel, which starts at a voltage not more than an emission starting voltage at which the light emitting layer starts emission and in which polarity is alternately reversed between positive and negative.Type: GrantFiled: October 25, 2005Date of Patent: July 5, 2011Assignee: Panasonic CorporationInventors: Masayuki Ono, Shogo Nasu, Toshiyuki Aoyama, Masaru Odagiri
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Publication number: 20110157144Abstract: A pixel of a display with reduced leakage current is disclosed. The pixel includes: an organic light emitting diode; a first transistor for controlling an amount of current flowing from a first power source to a second power source via the organic light emitting diode; a storage capacitor coupled between the first power source and a gate electrode of the first transistor; a plurality of third transistors coupled between the gate electrode and a second electrode of the first transistor; and a plurality of fourth transistors coupled between the gate electrode of the first transistor and an initialization power source. The third and fourth transistors are configured to reduce a leakage current from the storage capacitor to improve the image quality of the display.Type: ApplicationFiled: September 21, 2010Publication date: June 30, 2011Inventors: Yong-Sung Park, Bo-Yong Chung, Deok-Young Choi
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Patent number: 7956830Abstract: An organic light-emitting diode (OLED) panel and driving method thereof is provided. The OLED panel includes a plurality of data lines, scan lines, pixels, sampling voltage lines and compensation voltage lines. The sampling voltage line transmits a compensation voltage in response to compensation signals from the data lines, threshold voltages of driving transistors and organic light emitting diodes in the pixels connected to the same scan line. The corresponding compensation voltage line adjusts data signals transmitted into the pixels connected to the same scan line in response to the compensation voltage.Type: GrantFiled: April 25, 2007Date of Patent: June 7, 2011Assignee: AU Optronics Corp.Inventors: Yung-Chih Chen, Chih-Lung Lin, Yuan-Chun Wu
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Patent number: 7956824Abstract: A driver device for driving light emitting elements comprises a data latch having an input coupled to an input signal, a current control circuit having an input coupled to the data latch, and an output coupled to the input of an output stage, the latter being configured to drive the light emitting elements. The driver device has a power control circuit having an input coupled to the output of the data latch and an output coupled to the input of the current control circuit. The power control circuit is configured to control the current control circuit and the latter is configured to deliver a first current when the data inputted to the power control circuit is in a first state and a second current when at least part of the data inputted to the power control circuit is in a second state.Type: GrantFiled: July 26, 2007Date of Patent: June 7, 2011Assignee: STMicroelectronics S.r.l.Inventor: Nicola Li Volsi
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Patent number: 7956826Abstract: An electroluminescent (EL) display device has current-driven pixels and is operable in at least two phases within each frame period. In one phase, one of a first plurality (31) of analogue drive currents can be driven through EL display element. In another longer phase, one of a second plurality (33) of analogue drive currents is independently driven through the EL display element. This device combines a time ratio method with an analogue drive scheme. A shorter phase may provide the higher resolution (smaller) increments and one longer phase may provide lower resolution (larger) increments. Low brightness outputs can be achieved with a higher drive current, but over a short duration, which reduces non-uniformity in the pixel output.Type: GrantFiled: July 22, 2003Date of Patent: June 7, 2011Assignee: Koninklijke Philips Electronics N.V.Inventors: Mark J. Childs, David A. Fish
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Patent number: 7956828Abstract: In an organic electroluminescence display device (30) comprising an organic EL element (26) having a structure wherein an organic luminescent medium (24) is sandwiched between a top electrode (20) and a bottom electrode (22), and a driving circuit (14) for driving the organic EL element (26), the organic luminescent medium (24) comprises a host compound and a triplet-related luminous compound and the driving circuit (14) applies a electric pulse voltage or pulse current having a frequency of 30 Hz or more and a duty ratio of 1/5 or less. In this way, it is possible to provide an organic EL display device which consumes a low electric power and has a long luminous life span, and a method for driving the same.Type: GrantFiled: January 6, 2006Date of Patent: June 7, 2011Assignee: Idemitsu Kosan Co., Ltd.Inventors: Masahide Matsuura, Chishio Hosokawa
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Patent number: 7944459Abstract: A light-emitting device includes a plurality of light-emitting elements, each emitting light with a light amount according to a driving signal, a storage unit that stores first gray-scale data for assigning a gray-scale value of each of the plurality of light-emitting elements, a data processing unit that generates second gray-scale data from the first gray-scale data stored in the storage unit for each light-emitting element such that, as the gray-scale value assigned by the first gray-scale data is large, a gray-scale value assigned by the second gray-scale data is made small, and a driving unit that causes the individual light-emitting elements to emit light in a first period upon supply of a driving signal according to the first gray-scale data stored in the storage unit, and causes the individual light-emitting elements to emit light in a second period different from the first period upon supply of a driving signal according to the second gray-scale data generated by the data processing unit.Type: GrantFiled: September 7, 2006Date of Patent: May 17, 2011Assignee: Seiko Epson CorporationInventor: Takao Miyazawa
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Patent number: 7932881Abstract: A waveform generator can be constructed at a small area size using thin-film transistors and generates multiple triangular-wave voltage waveforms different from one another in phase, and an image display device that applies the waveform generator. A waveform generator that uses loop-form resistive wiring is provided on a substrate. The waveform generator supplies a triangular-wave voltage waveform or stepped voltage waveform of a voltage signal occurring in the loop-form resistive wiring to pixel circuits. The loop-form resistive wiring has multiple voltage supply switches that supply at least two kinds of voltages.Type: GrantFiled: October 10, 2006Date of Patent: April 26, 2011Assignee: Hitacji Displays, Ltd.Inventors: Hiroshi Kageyama, Hajime Akimoto
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Patent number: 7924249Abstract: A method and system for light emitting device displays is provided. The system includes one or more pixels, each having a light emitting device, a drive transistor for driving the light emitting device, and a switch transistor for selecting the pixel; and a circuit for monitoring and extracting the change of the pixel to calibrate programming data for the pixel. Programming data is calibrated using the monitoring result.Type: GrantFiled: February 9, 2007Date of Patent: April 12, 2011Assignee: Ignis Innovation Inc.Inventors: Arokia Nathan, G. Reza Chaji
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Patent number: 7898508Abstract: The present invention relates to a light emitting device for preventing a cross-talk phenomenon and a pectinated pattern. The light emitting device includes data lines, scan lines, pixels and a discharging circuit. The data lines are disposed in a first direction, and the scan lines are disposed in a second direction different from the first direction. The pixels are formed in cross areas of the data lines and the scan lines. The discharging circuit discharges at least one data line to a first discharge voltage during a first sub-discharging time of a discharging time, and changes the first discharge voltage into a second discharge voltage during a second sub-discharging time of the discharging time. The light emitting device discharges data lines to discharge voltages corresponding to cathode voltage of pixels, and so cross-talk phenomenon and pectinated pattern is not occurred in the light emitting device.Type: GrantFiled: October 5, 2006Date of Patent: March 1, 2011Assignee: LG Display Co., Ltd.Inventor: Ji Hun Kim
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Pixel circuit, display device, driving method of pixel circuit, and driving method of display device
Patent number: 7893895Abstract: A pixel circuit, disposed at a part where a scanning line and a signal line intersect each other, includes at least an electrooptic element, a drive transistor, a sampling transistor, and a retaining capacitance. The drive transistor has a gate connected to an input node, a source connected to an output node, and a drain connected to a predetermined power supply potential and supplies a driving current to the electrooptic element according to a signal potential retained in the retaining capacitance. The electrooptic element has one terminal connected to the output node and another terminal connected to a predetermined potential. The sampling transistor is connected between the input node and the signal line and operates when selected by the scanning line, samples an input signal from the signal line, and retains the input signal in the retaining capacitance. The retaining capacitance is connected to the input node.Type: GrantFiled: July 1, 2005Date of Patent: February 22, 2011Assignee: Sony CorporationInventors: Katsuhide Uchino, Junichi Yamashita -
Patent number: 7889188Abstract: This invention relates to a flat panel display device that is adaptive for perfectly compensating a panel defect by performing an electrical compensation on pixels in a panel defect location, and a method of controlling a picture quality thereof. A flat panel display device according to an embodiment of the present invention includes a display panel which has a non-defect area and a panel defect area; a memory which stores a first compensation, a second compensation data, a third compensation data, a fourth compensation data, and a fifth compensation data; a compensation part; and a driver for driving the display panel in use of the data modulated by the compensation part.Type: GrantFiled: June 28, 2007Date of Patent: February 15, 2011Assignee: LG Display Co., Ltd.Inventor: Jong Hee Hwang
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Patent number: 7880695Abstract: In a display apparatus including a correction unit and a switching transistor, the correction unit operates in a non-light emission period such that a correction voltage for eliminating an effect of a variation in a characteristic of a driving transistor is stored in a storage capacitor. The switching transistor is disposed between one current terminal of the driving transistor and a light emitting element. The switching transistor turns off during the non-light emission period thereby to electrically disconnect the light emitting element from the one current terminal of the driving transistor thereby preventing a leakage current from flowing through the light emitting element during the period in which the correction unit operates, and thus preventing the correction voltage from having an error due to the leakage current.Type: GrantFiled: February 19, 2008Date of Patent: February 1, 2011Assignee: Sony CorporationInventors: Junichi Yamashita, Masatsugu Tomida, Katsuhide Uchino
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Patent number: 7876314Abstract: A display apparatus includes a pixel array section and a driving section configured to drive the pixel array section. The pixel array section includes a plurality of first scanning lines and a plurality of second scanning lines extending along rows, a plurality of signal lines extending along columns, a plurality of pixels arranged in a matrix at positions at which the first and second scanning lines and the signal lines intersect with each other, and a plurality of power supply lines and a plurality of ground lines configured to perform feeding to the pixels. The driving section includes a first scanner, a second scanner, and a signal selector. Each of the pixels includes a light emitting element, a sampling transistor, a drive transistor, a switching transistor, and a pixel capacitance.Type: GrantFiled: June 11, 2007Date of Patent: January 25, 2011Assignee: Sony CorporationInventors: Katsuhide Uchino, Junichi Yamashita, Naobumi Toyomura
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Patent number: 7868856Abstract: A display has light emitting elements (2) arranged in rows and columns, with pixels in a column being supplied with current from a respective column power supply line (26). Target pixel drive currents are determined corresponding to desired pixel brightness levels based on a model of the pixel current-brightness characteristics. These are modified to take account of the voltage on the column power supply line (26) at each pixel resulting from the currents drawn from the column power supply line, and the dependency of the pixel brightness characteristics on the voltage on the column power supply line at the pixel. The invention addresses the problem of vertical cross-talk that occurs in active matrix LED displays due to the finite output impedance of the current providing TFTs as well as the finite resistance of metals used to form power supply lines.Type: GrantFiled: August 20, 2004Date of Patent: January 11, 2011Assignee: Koninklijke Philips Electronics N.V.Inventor: David A. Fish
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Patent number: 7852298Abstract: A method and system for driving a light emitting device display is provided. The system provides a timing schedule which increases accuracy in the display. The system may provide the timing schedule by which an operation cycle is implemented consecutively in a group of rows. The system may provide the timing schedule by which an aging factor is used for a plurality of frames.Type: GrantFiled: June 8, 2006Date of Patent: December 14, 2010Assignee: Ignis Innovation Inc.Inventors: Arokia Nathan, G. Reza Chaji
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Patent number: 7847764Abstract: A method for controlling and compensating aging in an LED device includes measuring a performance change in light output of the LED device. The LED device is controlled with a first compensation algorithm derived from the measured performance change, during a first period, to effect a luminance change over time in the light output of the LED device. Subsequently, a second compensation algorithm, derived from the measured performance change, and different from the first compensation algorithm, during a second period, effects a second luminance change over time in the LED device's light output. The second luminance change over time in the second period is different from the first luminance change over time in the first period. Furthermore, the first and second periods together are less than the lifetime of the LED device.Type: GrantFiled: March 15, 2007Date of Patent: December 7, 2010Assignee: Global OLED Technology LLCInventors: Ronald S. Cok, Felipe A. Leon, John E. Ludwicki
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Patent number: 7847763Abstract: A method for driving a passive matrix organic light emitting diode (PMOLED) is provided. A pulse width modulation (PWM) constant current is provided to OLED pixels connected to a segment of a PMOLED array without voltage pre-charging the segment. Then, an offset value corresponding to missing gray scales of the OLED pixel is determined. According to the missing gray scales, the gray scales of the OLED pixel are rescaled starting from the offset. The OLED pixel is thus driven by a compensated PWM constant current having the rescaled gray scales during each horizontal line period.Type: GrantFiled: June 9, 2005Date of Patent: December 7, 2010Assignee: Himax Technologies, Inc.Inventor: Shang-Li Chen
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Patent number: 7821478Abstract: Disclosed is a display apparatus which can improve the characteristics of TFTs used to select and drive self-emissive elements such as OLEDs. The display apparatus has row electrodes, column electrodes, and a driving unit. The self-emissive elements are formed in regions corresponding to intersections of the row electrodes with the column electrodes. Element driving circuits are formed for driving the self-emissive elements. Each of the element driving circuits includes a selection transistor, a capacitor, and a driving transistor. The driving unit applies a reverse bias to a control terminal of the driving transistor in a non-emission period in which the self-emissive element is not supplied with a driving current.Type: GrantFiled: January 30, 2006Date of Patent: October 26, 2010Assignee: Pioneer CorporationInventor: Masami Tsuchida
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Patent number: 7808455Abstract: Apparatus for compensating for a threshold voltage of a driver element having gate and drain electrodes which controls current flowing in a light emitting element effective in an on and off state. A capacitor is disposed between the gate electrode and a drain electrode when the light emitting element is in the on state emits light and when the light emitting element is in the off state, applying a voltage to the gate and the source of the driver element and a threshold voltage between the gate and drain electrodes is detected and stored in the capacitor, by writing a signal voltage closer to a potential which causes the driver element to turn off than the potential supplied to the gate electrode of the driver element when detecting a threshold value, the signal voltage being superimposed on the threshold voltage without losing the threshold voltage of the driver element.Type: GrantFiled: March 2, 2006Date of Patent: October 5, 2010Assignee: Global OLED Technology LLCInventor: Shinya Ono
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Patent number: 7804469Abstract: A display apparatus includes: a pixel array section and dependence cancellation means. The pixel array section wherein a plurality of pixel circuits each including an electro-optical element, a driving transistor configured to drive said electro-optical element, a sampling transistor configured to sample and write an input signal voltage and a capacitor configured to hold a gate-source voltage of said driving transistor within a display period are disposed in a matrix. The dependence cancellation means for negatively feeding back, within a correction period before said electro-optical element emits light in a state wherein the input signal voltage is written by said sampling transistor, drain-source current of said driving transistor to the gate input side of said driving transistor to cancel the dependence of the drain-source current of said driving transistor on the mobility.Type: GrantFiled: July 26, 2007Date of Patent: September 28, 2010Assignee: Sony CorporationInventor: Mitsuru Asano
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Patent number: 7800563Abstract: Disclosed herein is a display apparatus, including: a pixel array section wherein a plurality of pixel circuits each including an electro-optical element, a driving transistor, a sampling transistor and a capacitor are disposed in a matrix; a dependence cancellation section configured to negatively feed back, within a correction period before said electro-optical element emits light in a state wherein the image signal is written by said sampling transistor, drain-source current of said driving transistor to the gate input side of said driving transistor to cancel the dependence of the drain-source current of said driving transistor on the mobility; and a scanning section configured to use an AC power supply as a power supply to a last stage buffer of an output circuit to produce a scanning signal which defines the correction period.Type: GrantFiled: July 31, 2007Date of Patent: September 21, 2010Assignee: Sony CorporationInventors: Mitsuru Asano, Hiroshi Fujimura, Seiichiro Jinta, Masatsugu Tomida
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Patent number: 7773060Abstract: A method, medium, and apparatus compensating for differences in the persistence of phosphors in a display panel. The method of compensating for differences in persistence of phosphors in a display panel, having two or more light-emitting elements with different response characteristics, may include compensating for the response time of a first light-emitting element that represents the longest response time, selecting data response time for a second light-emitting element, which is different from the longest response time, and compensating for the differences in the persistence of phosphors due to a difference between the response times of the first light-emitting element and the second light-emitting element by compensating for the selected video data based on the compensated video data for the first light-emitting element.Type: GrantFiled: July 11, 2006Date of Patent: August 10, 2010Assignee: Samsung Electronics Co., Ltd.Inventors: Hyun-hwa Oh, Ho-young Lee, Du-sik Park, Sung-su Kim, Chang-yeong Kim
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Patent number: 7773056Abstract: A pixel circuit for a light emitting display. Adjacent pixels of the light emitting display coupled to one scan line share one first power supply line. A driving circuit in each pixel circuit drives first and second organic light emitting diodes (OLEDs). A switching circuit is coupled between the first and second OLEDs and the driving circuit to sequentially control the driving of the first and second OLEDs. Because two adjacent pixel circuits share one pixel power supply line and a plurality of OLEDs are coupled to one pixel circuit, it is possible to reduce the number of pixel circuits and the number of wiring lines of the light emitting display. Other circuit elements may also be shared between adjacent pixel circuits. Reducing the wiring and other elements of the pixel circuits makes it possible to increase the aperture ratio of the light emitting display.Type: GrantFiled: November 14, 2005Date of Patent: August 10, 2010Assignee: Samsung Mobile Display Co., Ltd.Inventors: Won Kyu Kwak, Sung Cheon Park
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Patent number: 7764248Abstract: In a display in which pixel circuits each including a drive transistor, switching transistors and a capacitor are arranged in rows and columns, two-stage mobility correction is implemented in which mobility correction with an intermediate grayscale level (gray level) is executed before mobility correction is executed with an input signal (Vsig) level being written to the gate of the drive transistor when the switching transistor is in the conducting state. Thus, even if the mobility correction period is constant, mobility correction can be implemented for all the grayscales within the mobility correction period. This feature allows achievement of a uniform image quality free from streaks and unevenness attributed to variation in the mobility from pixel to pixel.Type: GrantFiled: October 13, 2006Date of Patent: July 27, 2010Assignee: Sony CorporationInventors: Tetsuro Yamamoto, Katsuhide Uchino, Junichi Yamashita
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Patent number: 7755579Abstract: The invention provides an image display apparatus and an image display method of excellent image quality, by correcting the voltage drop resulting from the electrical resistance of the wirings with a simple configuration. There are provided adjustment data calculation means for calculating, for input image data, adjustment data for correcting the influence of the voltage drop resulting from the electrical resistance of the row wirings and gray scale number converting means for converting the number of gradation levels of the adjustment data. Modulation means outputs a signal modulated in the voltage amplitude to each column wiring, based on the adjustment data outputted by and subjected to the conversion of gradation levels by the gray scale number converting means.Type: GrantFiled: July 20, 2006Date of Patent: July 13, 2010Assignee: Canon Kabushiki KaishaInventors: Osamu Sagano, Naoto Abe, Hiroshi Saito
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Publication number: 20100156766Abstract: An electroluminescent (EL) subpixel driven by a digital-drive scheme has a readout transistor driven by a current source when the drive transistor is non-conducting. This produces an emitter-voltage signal from which an aging signal representing the efficiency of the EL emitter can be computed. The aging signal is used to determine the loss in current of the subpixel when active, and an input signal is adjusted to provide increased on-time to compensate for voltage rise and efficiency loss of the EL emitter. Variations due to temperature can also be compensated for.Type: ApplicationFiled: December 18, 2008Publication date: June 24, 2010Inventors: Charles I. Levey, Fellpe A. Leon, John W. Hamer, Gary Parett, Christopher J. White
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Publication number: 20100156886Abstract: A display device for performing display by digitally driving pixels, arranged in a matrix arrangement, according to image data of an image signal. A data driver allocates pixel data for a single pixel to corresponding sub-frames as a plurality of bit data, and digitally drives each pixel by providing bit data to each pixel, the bit data having one frame formed from a specified number of unit frames. A timing control circuit divides the image signal into blocks for analysis, analyzes likelihood of occurrence of pseudo contours for each block, and analyzes likelihood of occurrence of pseudo contours for display of a single screen based on analysis results in each block. The timing control circuit then changes display based on the image signal based on analysis results by the timing control circuit.Type: ApplicationFiled: November 10, 2009Publication date: June 24, 2010Inventor: Kazuyoshi Kawabe
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Patent number: 7719493Abstract: A data driving circuit, used to drive display devices, comprises a digital-to-analog current converter (DAC), a reset circuit connected to the output terminal of the DAC for resetting the output potential of the DAC to a specific gray scale potential, and plural stages of data driver units connected to the output terminal of the DAC and the reset circuit to drive data lines of the display devices. Each of the data driver units comprises a sample-holding circuit and a control circuit.Type: GrantFiled: April 20, 2006Date of Patent: May 18, 2010Assignee: Au Optronics Corp.Inventor: Hui-Ya Huang
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Patent number: 7719501Abstract: A distinct color LCD apparatus including at least two layers of respectively disparate encapsulated liquid crystal materials; Structural means for maintaining said layers proximate to each other and in a substantially parallel orientation; Electrically conductive means for addressing at least one substantially parallel address across the encapsulated liquid crystal material in each of the respective layers; and Coordinated with said means for addressing, an electrical pulse driving means (I) wherein a state is selected from the list Homeouopre and planar and (U) whereby said state is communicated to a predetermined address between one of said parallel layers.Type: GrantFiled: September 30, 2003Date of Patent: May 18, 2010Assignee: Magink Display Technologies Ltd.Inventors: Amir Ben-Shalom, David Coates
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Patent number: 7719492Abstract: An active matrix electroluminescent display device has a shorting transistor (30) connected between the gate and drain of the drive transistor (22). Means (42) is provided for measuring a voltage on the data line (6). The shorting transistor (30) can be used to discharge the voltage on the gate of the drive transistor (22) until it switches off. By storing the resultant voltage on the data line (6) through an address transistor (16), the data line is used as one of the control/measurement lines for the threshold measurement.Type: GrantFiled: January 4, 2005Date of Patent: May 18, 2010Assignee: Koninklijke Philips Electronics N.V.Inventor: Mark J. Childs
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Patent number: 7714814Abstract: The present invention relates to a method and apparatus for driving an electro-luminescence display panel capable of doing an aging operation upon driving. A method of driving an electro-luminescence display panel according to the present invention includes: a scan period when electro-luminescence cells formed at a cross of both a plurality of scan lines and a plurality of data lines are line-sequentially emitted; and an aging period when an aging is performed in the electro-luminescence cells at the same time by applying a reverse bias, wherein the scan period and the aging period are repeated for each frame.Type: GrantFiled: August 17, 2005Date of Patent: May 11, 2010Assignee: LG Electronics Inc.Inventors: Hyo Dae Bae, Hak Su Kim
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Patent number: 7714810Abstract: The invention provides an electro-optical apparatus that can prevent a shift in a threshold voltage of an amorphous silicon transistor while driving an organic EL device in a pixel circuit including the amorphous silicon transistor. A characteristic-adjustment circuit can be provided, which has a function of returning a shift in the threshold voltage of the amorphous silicon transistor included in the pixel circuit to the original state.Type: GrantFiled: May 12, 2004Date of Patent: May 11, 2010Assignee: Seiko Epson CorporationInventors: Toshiyuki Kasai, Yoichi Imamura, Tokuro Ozawa
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Patent number: 7692613Abstract: Circuits for a pixel in a light emitting display capable of displaying an image with desired brightness are described. The pixel circuit includes a driver to supply a pixel current to the light emitting device corresponding to a data signal supplied from a data line, a first switching unit coupled between the driver and the data line, and a second switching unit coupled between the data line and a common node formed between the driver and the light emitting device. The driver, in turn, includes a first transistor to generate the pixel current to be supplied from a first power line to the light emitting device, a first capacitor coupled between the first transistor and the first switching unit to be charged with a voltage corresponding to the threshold voltage of the first transistor, and a second capacitor to be charged with a voltage corresponding to the data signal.Type: GrantFiled: May 25, 2005Date of Patent: April 6, 2010Assignee: Samsung Mobile Display Co., Ltd.Inventors: Sang Moo Choi, Hong Kwon Kim, Oh Kyong Kwon
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Patent number: 7671825Abstract: According to one aspect of the present invention, it is possible to sufficiently perform the discharging of charge without lowering the light emitting efficiency of an organic EL device and hence, the device can exhibit the light emitting efficiency higher than a conventional organic EL device and, at the same time, can prevent the degradation of the device. As an organic EL device to which the present invention is applied, on a glass transparent substrate, a transparent electrode, a hole injection layer and a hole transport layer which function as a hole transport function layer, a light emitting layer, an electron transport function layer, and a metal electrode are formed sequentially, and a drive power sources are connected to the transparent electrode and the metal electrode.Type: GrantFiled: February 24, 2006Date of Patent: March 2, 2010Assignee: Hitachi Displays, Ltd.Inventors: Norikazu Uchiyama, Masaaki Okunaka, Masahiro Nishizawa, Hidetsugu Matsukiyo, Yuko Matsumoto
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Patent number: 7663581Abstract: A light emitting display increases the lifetime of a light emitting element by reverse biasing the light emitting element without using an additional power source and a power source line. The light emitting element is reverse biased without using the power source and the power source line for the reverse bias because a low level light emitting scan signal is used. The aperture ratio, contrast ratio, and lifetime of the light emitting display are increased.Type: GrantFiled: November 3, 2005Date of Patent: February 16, 2010Assignee: Samsung Mobile Display Co., Ltd.Inventor: Won-Kyu Kwak
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Patent number: 7663616Abstract: A data driving circuit for displaying an image with a desired brightness comprises: a current digital-analog converter for generating a gradation current corresponding to external data, and for receiving a first current corresponding to the gradation current from a pixel via a data line; a current control unit for receiving a pixel current from the pixel via the data line, and for selectively increasing and decreasing a level of the first current in accordance with the received pixel current; and a selection unit for selectively connecting the data line to either the current digital-analog converter or the current control unit. An organic light emitting diode and a method of driving same are similarly configured. With these configurations, an image is displayed with desired brightness.Type: GrantFiled: December 22, 2005Date of Patent: February 16, 2010Assignee: Samsung Mobile Display Co., Ltd.Inventors: Sang-Moo Choi, Hong-Kwon Kim, Oh-Kyong Kwon
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Patent number: 7652803Abstract: The object of the invention is to extend the life of the light source while uniformizing the illuminance intensity in the main scanning direction. The invention is based on a light source of image reading apparatus comprised of film layers laminated on a transparent substrate in the order of a transparent electrode, an area light emitter and a metal electrode, and emitting light by impressing a specific voltage on these two electrodes. And an area light emitter column configured by arranging area light emitters corresponding to each color of R (red), G (green) and B (blue) in the sub scanning direction, or a monochrome area light emitter is arranged repeatedly in the main scanning direction. Accordingly, even when somewhere in the light emitting element has a defect like the film thickness is thin, the current gathering at this point with the low resistance value becomes a very small volume. Therefore, it would not occur that the film burns out from here.Type: GrantFiled: April 3, 2007Date of Patent: January 26, 2010Assignee: Panasonic CorporationInventors: Tetsuroh Nakamura, Masakazu Mizusaki, Ken-ichi Masumoto
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Patent number: 7652646Abstract: Systems for displaying images are provided.Type: GrantFiled: April 14, 2006Date of Patent: January 26, 2010Assignee: TPO Displays Corp.Inventor: Ching-Wei Lin