Having Compensating Pulse Patents (Class 345/78)
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Patent number: 8325169Abstract: A pixel circuit provided on a substrate on which a signal line, first and second scanning lines supplying first and second control pulse signals, a fixed power line, and a variable power line are arranged includes a capacitance element, a sampling transistor connected between the signal line and one of ends of the capacitance element, where the gate of the sampling transistor is connected to the first scanning line, a drive transistor of which gate is connected to the other end, where one of a drain and a source of the drive transistor is connected to the fixed power line, an initializing transistor of which gate is connected to the second scanning line, which is connected between the other end and the other of the drain and the source, and a light emitting element connected between the variable power line and the other of the drain and the source.Type: GrantFiled: September 29, 2009Date of Patent: December 4, 2012Assignee: Sony CorporationInventor: Takao Tanikame
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Patent number: 8319708Abstract: A pixel for an organic light emitting diode display is disclosed. The pixel includes a capacitor configured to be charged with a voltage which compensates for the threshold voltage and mobility of the transistor driving the organic light emitting diode of the pixel.Type: GrantFiled: July 17, 2009Date of Patent: November 27, 2012Assignee: Samsung Display Co., Ltd.Inventors: Myoung-Hwan Yoo, Keum-Nam Kim
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Patent number: 8319713Abstract: A pixel capable of compensating for deterioration of an organic light emitting diode includes an organic light emitting diode. A pixel circuit includes a first transistor controlling an amount of current supplied from a first power supply to the organic light emitting diode corresponding to a data signal. A compensating unit controls a voltage of a gate electrode of the first transistor to compensate for deterioration of the organic light emitting diode. The compensating unit includes a second transistor coupled between the gate electrode of the first transistor and the organic light emitting diode and turned off during a period of the supply of the data signal to the pixel circuit, and a feedback capacitor coupled between the second transistor and the organic light emitting diode.Type: GrantFiled: February 3, 2009Date of Patent: November 27, 2012Assignee: Samsung Display Co., Ltd.Inventor: Sang-Moo Choi
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Patent number: 8310419Abstract: The present invention relates to a display device and a driving method thereof. The display device includes a light emitting device, a capacitor connected between a first electrical contact and a second electrical contact, a driving transistor, a switching transistor being controlled by a scanning signal to be connected between a data voltage and the first electrical contact, a first compensation transistor being controlled by a first compensation signal to be connected between the first electrical contact and a first voltage, and a second compensation transistor being controlled by a second compensation signal to be connected between the second electrical contact and a second voltage. The driving transistor includes an input terminal that is connected to a driving voltage, an output terminal that is connected to the second electrical contact, and a control terminal that is connected to the first electrical contact.Type: GrantFiled: December 26, 2008Date of Patent: November 13, 2012Assignee: Samsung Display Co., Ltd.Inventors: Doo-Hyung Woo, Kwang-Sub Shin, Young-Il Kim, Ji-Hye Eom
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Patent number: 8310414Abstract: An information processing apparatus includes a self-luminous type display, a current value predicting unit for predicting, based on a pixel value of a next image, the value of a current required by the display that displays the next image, and a controller for controlling luminance of the display based on the predicted current value.Type: GrantFiled: September 9, 2005Date of Patent: November 13, 2012Assignee: Sony CorporationInventor: Ken Tamayama
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Patent number: 8305310Abstract: A display device including pixels has formed therein at least two driving blocks each made up of pixel rows, and includes: a signal line driving circuit that outputs a signal voltage to an output line disposed in each of pixel columns; and a selector circuit that provides a signal voltage outputted from the output line to one of a first signal line and a second signal line which are provided in each of the columns, provides a standard voltage from a standard voltage source to one of the two signal lines, and provides the signal voltage and the standard voltage mutually exclusively to the two signal lines. Each of the pixels includes a current control unit and an organic EL element. Pixels in the k-th driving block are connected to the first signal line and pixels in the (k+1)-th driving block are connected to the second signal line.Type: GrantFiled: April 10, 2012Date of Patent: November 6, 2012Assignee: Panasonic CorporationInventors: Masafumi Matsui, Shinya Ono
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Patent number: 8300009Abstract: An electrophoretic display according to the present invention includes a first reset step for applying a first voltage to electrophoretic devices such that no image is displayed and no afterimages are present in the electrophoretic devices between a first step for displaying a first image on the electrophoretic devices and a second step for displaying a second image on the electrophoretic devices and a second reset step for applying a second voltage higher than the first voltage such that no image is displayed and no afterimage is present in the electrophoretic devices at a frequency less than that at which the first reset step is performed.Type: GrantFiled: March 1, 2010Date of Patent: October 30, 2012Assignee: Seiko Epson CorporationInventor: Kazunori Hiramatsu
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Patent number: 8289245Abstract: The present invention provides a display device, a method for driving the same, and an electronic device capable of making ? correction function reliably even in the case where light emission luminance is low. A potential difference between the gate and the source of a transistor is corrected to a threshold voltage of the transistor. After that, while a horizontal drive circuit outputs a third voltage Vofs2, correction of mobility of the transistor starts. Subsequently, while the horizontal drive circuit outputs a second voltage Vsig, writing of a voltage according to the second voltage Vsig to the gate of the transistor is started.Type: GrantFiled: July 23, 2009Date of Patent: October 16, 2012Assignee: Sony CorporationInventor: Shoji Araki
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Patent number: 8289234Abstract: An Organic Light Emitting Display (OLED) that is capable of decreasing the number of output lines for a data driver using a demultiplexer, displaying an image with uniform brightness, and adjusting white balance includes: a plurality of red, green and blue sub-pixels, and each sub-pixel is provided with an auxiliary capacitor to compensate a decreased driving voltage. The respective auxiliary capacitors are different in capacitance according to emission efficiency of the red, green and blue sub-pixels. The auxiliary capacitor of the green sub-pixel has a larger capacitance than the auxiliary capacitor of the red sub-pixel, and the auxiliary capacitor of the red sub-pixel has a larger capacitance than the auxiliary capacitor of the blue sub-pixel. This enables the white balance to be adjusted with the same data voltage.Type: GrantFiled: July 18, 2006Date of Patent: October 16, 2012Assignee: Samsung Display Co., Ltd.Inventor: Yang-Wan Kim
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Patent number: 8289244Abstract: A pixel circuit has a light emitting element and a driver electrically connected to the light emitting element. A reverse bias voltage is applied to the driver to reduce a shift amount of a threshold voltage of the driver.Type: GrantFiled: June 26, 2007Date of Patent: October 16, 2012Assignee: LG Display Co., Ltd.Inventors: Taro Hasumi, Yoshinao Kobayashi, Keigo Kanoh
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Patent number: 8289311Abstract: The display device may include a data aligning part that analyzes a gray level of input data and inserts black data into frame data having less than a designated reference gray level; and a driver that displays the data from the data aligning part in a display panel.Type: GrantFiled: December 5, 2006Date of Patent: October 16, 2012Assignee: LG Display Co., Ltd.Inventor: Sung Hak Jo
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Patent number: 8284130Abstract: The inventors found out that in the case of performing a low gray scale display in which a very small amount of current is supplied to a light emitting element, variations in threshold voltages of driving transistors become notable since the gate-source voltage is low. In view of this, the invention provides a display device in which variations in the threshold voltages of the driving transistors are reduced even in the low gray scale display, and a driving method thereof. According to the invention, a gate-source voltage of the driving transistor is set higher in the low gray scale display than that in the high gray scale display. As one mode to achieve this, different power source lines are provided for the low gray scale display and the high gray scale display and their potentials are set to be different.Type: GrantFiled: August 17, 2007Date of Patent: October 9, 2012Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventors: Keisuke Miyagawa, Hajime Kimura
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Patent number: 8279143Abstract: 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: July 11, 2011Date of Patent: October 2, 2012Assignee: Ignis Innovation Inc.Inventors: Arokia Nathan, Gholamreza Chaji
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Patent number: 8274457Abstract: A driving device of a light emitting unit is provided. The driving device includes a driving circuit, a switch, a capacitor, and a compensation circuit. The driving circuit has a control terminal and a driving terminal connected to the light emitting unit. The driving circuit determines a driving current according to the voltage on the control terminal. The switch has a first end for receiving a data voltage, a second end connected to the light emitting unit, and a control end for receiving a scan voltage. The capacitor has a first end connected to the control terminal of the driving circuit and a second end connected to the second end of the switch. The compensation circuit has an output terminal connected to the first end of the capacitor. The compensation circuit supplies a reset voltage to the first end of the capacitor when the switch is turned on.Type: GrantFiled: March 23, 2010Date of Patent: September 25, 2012Assignee: Au Optronics CorporationInventor: Tsung-Ting Tsai
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Patent number: 8269798Abstract: A method of controlling a passive matrix display having rows and columns of pixels including receiving an input image signal; determining drive signals for at least a first image field and a second image field; calculating a value that is correlated to a change in the total capacitive charge of the pixels that will occur between the display of the first image field and the second image field for at least one column of the passive-matrix, electro-luminescent display; adjusting at least one of the drive signals within first or second image fields to compensate for the change in total capacitive charge; and providing adjusted drive signals for each pixel.Type: GrantFiled: July 18, 2007Date of Patent: September 18, 2012Assignee: Global OLED Technology LLCInventors: Michael E. Miller, Andrew D. Arnold, John F. Hamilton, Jr.
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Patent number: 8264431Abstract: Embodiments of the present invention provide for an array, and corresponding method of forming an array, that includes a plurality of light emitting devices. The light emitting devices are disposed over a substrate, and a photodetector detects light emitted through the substrate from the light emitting devices. Further, a substantially constant brightness may be maintained in a plurality of light emitting devices disposed over the upper surface of a substrate in an array. Light emitted through the substrate from each of the light emitting devices is measured, and the voltage level applied to each of the light emitting devices is varied to maintain a substantially constant brightness level of light emitted from the light emitting devices.Type: GrantFiled: October 23, 2003Date of Patent: September 11, 2012Assignee: Massachusetts Institute of TechnologyInventors: Vladimir Bulovic, Jonathan R. Tischler, Jennifer Yu
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Patent number: 8253663Abstract: A display apparatus and display driving method. A selective scan operation is performed on pixel circuits in row units, and a threshold-voltage correction operation is also performed to correct variations of the threshold voltage of respective pixel circuit driving transistors. Before performing the threshold-voltage correction operation in a horizontal scan period, a preparatory operation is performed in order to fix each of the electric potentials appearing on the gate and the source of the driving transistor at a predetermined level.Type: GrantFiled: March 19, 2008Date of Patent: August 28, 2012Assignee: Sony CorporationInventors: Takayuki Taneda, Tetsuro Yamamoto, Yukihito Iida, Katsuhide Uchino
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Patent number: 8248334Abstract: Disclosed herein is a method of driving an organic electroluminescence emission portion, the method including the steps of: applying a first node initialization voltage to corresponding one of the data lines, and supplying the video signal instead of the first node initialization voltage for a predetermined scanning time period, applying the first node initialization voltage from the corresponding one of the data lines to the first node through the write transistor held in an ON state for initializing the potential at the first node, and holding a state of applying the first node initialization voltage from the corresponding one of the data lines to the first node through the write transistor held in an ON state for holding the potential at the first node.Type: GrantFiled: August 26, 2008Date of Patent: August 21, 2012Assignee: Sony CorporationInventors: Naobumi Toyomura, Tetsuro Yamamoto, Katsuhide Uchino
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Patent number: 8232932Abstract: The present invention suppresses the generation of a leak current that accompanies the polarity inversion of the voltage waveform of the opposing electrode. The display device that performs display by sequentially scanning a plurality of scan signal lines in a single cycle period comprises: a plurality of data signal lines that intersect the scan signal lines; a pixel electrode that is connected to the data signal lines; and an opposing electrode that is disposed opposite the pixel electrode and for which the polarity of an application voltage is inverted in each of the cycle periods. The cycle period includes a scan period in which one full scan of the scan signal lines is performed and a non-scan period in which the scan signal lines are not scanned.Type: GrantFiled: September 27, 2007Date of Patent: July 31, 2012Assignee: Citizen Holdings Co., Ltd.Inventors: Rintarou Takahashi, Takashi Akiyama
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Patent number: 8232935Abstract: Disclosed herein is a display apparatus, including: a pixel array section including a plurality of pixels, a writing transistor, a driving transistor, a first switching transistor, a holding capacitor, and a second switching transistor; a first scanning section configured to drive the writing transistor in a unit of a row of the pixels; a second scanning section configured to drive the switching transistors in synchronism with scanning by the first scanning section; and a third scanning section configured to control the second switching transistors to a non-conducting state within a period after the image signal is written by the writing transistor until the signal writing period of the same row of the pixels ends but to a conducting state within any other period.Type: GrantFiled: May 21, 2008Date of Patent: July 31, 2012Assignee: Sony CorporationInventors: Yutaka Mitomi, Masatsugu Tomida, Katsuhide Uchino
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Patent number: 8232939Abstract: A system and method for driving an AMOLED display is provided. The AMOLED display includes a plurality of pixel circuits. A voltage-programming scheme, a current-programming scheme or a combination thereof is applied to drive the display. Threshold shift information, and/or voltage necessary to obtain hybrid driving circuit may be acquired. A data sampling may be implemented to acquire a current/voltage relationship. A feedback operation may be implemented to correct the brightness of the pixel.Type: GrantFiled: February 14, 2012Date of Patent: July 31, 2012Assignee: Ignis Innovation, Inc.Inventors: Arokia Nathan, Rick Huang, Stefan Alexander
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Patent number: 8223094Abstract: Display devices and methods capable of reversing brightness deterioration in electroluminescence elements while maintaining display quality, with simple pixel circuits and no manufacturing yield reduction, are provided. A display device includes luminescence pixels that each include a driving transistor, a luminescence element, and a switching transistor which switches between conduction and non-conduction states between a data line and the luminescence element. A data driving circuit supplies a signal voltage to the data line and a bias supplying circuit supplies a specified bias voltage to the data line. A control unit applies the specified bias voltage to an anode or cathode of the luminescence element by causing conduction between the data line and the data driving circuit, causing non-conduction between the data line and the bias supplying circuit, and turning the switching transistor ON, all within a period in which a signal current does not flow to the luminescence element.Type: GrantFiled: February 26, 2010Date of Patent: July 17, 2012Assignee: Panasonic CorporationInventors: Mika Nakamura, Kenichi Masumoto
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Patent number: 8217866Abstract: A data driving circuit capable of displaying images having uniform brightness. The present invention provides a data driving circuit of a display device having: at least one current sinking unit for controlling a predetermined current to flow in a data line; at least one voltage generating unit for resetting voltage values of enhancement voltages using a compensation voltage generated when the predetermined current flows; at least one digital-analog converter for selecting as a data signal one of the enhancement voltages to correspond to a digital value of externally supplied data; at least one boosting unit for boosting a voltage value of the data signal; and at least one switching unit for providing the data line with the boosted data signal.Type: GrantFiled: July 20, 2006Date of Patent: July 10, 2012Assignees: Samsung Mobile Display Co., Ltd., IUCF-HYU (Industry-University Cooperation Foundation Hanyang University)Inventors: Do Hyung Ryu, Bo Yong Chung, Oh Kyong Kwon
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Patent number: 8217862Abstract: Disclosed herein is a display apparatus, including: a pixel array section having a plurality of pixels each including an electro-optical element, a writing transistor, a driving transistor, and a holding capacitor; a power supply scanning circuit; and a signal outputting circuit; wherein the power supply scanning circuit is operable to supply a second power supply potential to initialize the potential of a second electrode of the driving transistor and then change over the potential of a power supply line to a first power supply potential; and the signal outputting circuit is operable to output, when the writing transistor is in a conducting state, a first reference potential, supply, midway while a threshold value correction process is carried out, a second reference potential, output a third reference potential within a period within which the writing transistor remains in the conducting state, and output a image signal after the threshold correction process ends.Type: GrantFiled: October 1, 2008Date of Patent: July 10, 2012Assignee: Sony CorporationInventors: Tetsuo Minami, Masatsugu Tomida
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Patent number: 8207918Abstract: During a first period of a set period, a reset switch element of each pixel is turned on to converge a voltage at a control electrode of a TFT to a predetermined voltage, and a step signal having a first voltage level is supplied from a step signal generation circuit. During a second period of the set period, the reset switch element is turned off, and a step signal having a second voltage level is supplied from the step signal generation circuit, whereby a voltage exceeding a second power supply voltage or a voltage exceeding a voltage range supplied from a signal driver section is input as a characteristic value set voltage to the control electrode. Accordingly, even when a relationship between a gate voltage and a drain current of the thin film transistor exhibits a hysteresis characteristic, uniform display can be achieved.Type: GrantFiled: June 9, 2009Date of Patent: June 26, 2012Assignees: Hitachi Displays, Ltd., Panasonic Liquid Crystal Display Co., Ltd.Inventors: Tohru Kohno, Takahide Kuranaga, Hiroshi Kageyama, Hajime Akimoto
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Patent number: 8199074Abstract: A representative system for displaying images comprises a pixel array, a conversion circuit, a memory device, and a compensation circuit. The pixel array has a plurality of pixels, each having at least one organic light emitting element equipped with a sensing unit which retrieves display information when the organic light emitting element retrieves a test signal. The conversion circuit determines a display parameter of each organic light emitting element according to the test signal and the display information of each organic light emitting element. The memory device stores the display parameter of each organic light emitting element. The compensation circuit modifies a video signal in accordance with the display parameters stored in the memory device.Type: GrantFiled: August 11, 2006Date of Patent: June 12, 2012Assignee: Chimei Innolux CorporationInventors: Shou-Cheng Wang, Shih-Chang Chang
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Publication number: 20120139894Abstract: A system and method for driving an AMOLED display is provided. The AMOLED display includes a plurality of pixel circuits. A voltage-programming scheme, a current-programming scheme or a combination thereof is applied to drive the display. Threshold shift information, and/or voltage necessary to obtain hybrid driving circuit may be acquired. A data sampling may be implemented to acquire a current/voltage relationship. A feedback operation may be implemented to correct the brightness of the pixel.Type: ApplicationFiled: February 14, 2012Publication date: June 7, 2012Applicant: Ignis Innovation, Inc.Inventors: Arokia Nathan, Rick Huang, Stefan Alexander
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Patent number: 8194013Abstract: An organic light emitting display capable of minimizing power consumption. The organic light emitting display includes a plurality of pixels positioned at intersections of data lines and scan lines includes the pixels including driving transistors positioned in an effective display region to control an amount of current that flows from a first power source to a second power source, a data driver for supplying data signals to the data lines, a scan driver supplying scan signals to the scan lines, a first power source generator generating the first power source, a second power source generator generating the second power source, and a voltage controller controlling the second power source generator so that voltage of the second power source is changed in response to a first voltage applied to an organic light emitting diode (OLED) included in a specific pixel when a data signal corresponding to specific brightness is supplied from the data driver to the specific pixel.Type: GrantFiled: July 20, 2009Date of Patent: June 5, 2012Assignee: Samsung Mobile Display Co., Ltd.Inventor: Sang-Moo Choi
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Patent number: 8188946Abstract: A method and system for compensation for luminance degradation in electro-luminance devices is provided. The system includes a pixel circuit having a light emitting device, a storage capacitor, a plurality of transistors, and control signal lines to operate the pixel circuit. The storage capacitor is connected or disconnected to the transistor and a signal line(s) when programming and driving the pixel circuit.Type: GrantFiled: September 12, 2006Date of Patent: May 29, 2012Assignee: Ignis Innovation Inc.Inventors: Arokia Nathan, G. Reza Chaji, Shahin Jafarabadiashtiani
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Patent number: 8174466Abstract: Disclosed herein is a display device including: a pixel array unit having pixel circuits arranged in a form of a matrix; and a control unit having a writing scanning unit for outputting, to the sampling transistor, a writing scanning pulse. The control unit effects control to supply a control input terminal of the drive transistor with a fixed potential for a threshold value correcting operation for retaining a voltage corresponding to a threshold voltage of the drive transistor in the storage capacitor. When setting a voltage across the storage capacitor to the threshold voltage of the drive transistor by repeating the threshold value correcting operation a plurality of times on a time division basis, the control unit effects control to perform each the threshold value correcting operation and the sampling transistor to a conducting state.Type: GrantFiled: February 12, 2008Date of Patent: May 8, 2012Assignee: Sony CorporationInventors: Naobumi Toyomura, Katsuhide Uchino, Tetsuro Yamamoto
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Patent number: 8164549Abstract: An electronic circuit drives a driven element. The electronic circuit includes a signal line, a unit circuit connected to the signal line, and a voltage supply line. The unit circuit includes a transistor, a switch, and a capacitive element. The transistor includes a gate terminal, a first terminal, a second terminal connected to the voltage supply line, and a channel between the first and second terminals. The switch controls electrical connection between the gate terminal and one of the first and second terminals. A conductive state between the first and second terminals is controlled by a gate voltage applied to the gate terminal. During a first period, the switch is changed from an off state to an on state. During a second period, the switch is changed to an off state.Type: GrantFiled: October 2, 2007Date of Patent: April 24, 2012Assignee: Seiko Epson CorporationInventor: Takashi Miyazawa
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Patent number: 8159425Abstract: 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: March 16, 2009Date of Patent: April 17, 2012Assignee: LG Electronics Inc.Inventors: Hyo Dae Bae, Hak Su Kim
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Patent number: 8159482Abstract: For making outputs of a drive circuits accurate, the drive circuit is composed of a plurality of current signal generation circuits for outputting a current signal to each of a plurality of output units, a current signal output line to which outputs of the plurality of current signal generation circuits are commonly connected, a correction value output circuit for outputting a correction value obtained by evaluating the output of one or more specific circuits of the plurality of current signal generation circuits on a basis of current values output through the current signal output line, and a correction circuit for correcting an image signal supplied to the current signal generation circuits by means of the correction value.Type: GrantFiled: March 5, 2008Date of Patent: April 17, 2012Assignee: Canon Kabushiki KaishaInventors: Somei Kawasaki, Fujio Kawano, Masami Iseki
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Patent number: 8154539Abstract: For making outputs of a drive circuits accurate, the drive circuit is composed of a plurality of current signal generation circuits for outputting a current signal to each of a plurality of output units, a current signal output line to which outputs of the plurality of current signal generation circuits are commonly connected, a correction value output circuit for outputting a correction value obtained by evaluating the output of one or more specific circuits of the plurality of current signal generation circuits on a basis of current values output through the current signal output line, and a correction circuit for correcting an image signal supplied to the current signal generation circuits by means of the correction value.Type: GrantFiled: March 5, 2008Date of Patent: April 10, 2012Assignee: Canon Kabushiki KaishaInventors: Somei Kawasaki, Fujio Kawano, Masami Iseki
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Patent number: 8154483Abstract: Disclosed is an image display wherein luminance change due to change of the light-emitting device over time is compensated while suppressing affects of characteristics change in the drive transistor. Specifically disclosed is an image display comprising a plurality of pixels, wherein each pixel has a light-emitting device (OLED) which emits light when current is passed therethrough, a driver device (Td) for controlling light emission of the light-emitting device, and a control circuit (A) which is electrically connected to the light-emitting device and the driver device, and directly or indirectly detects the voltage applied to the light-emitting device at least during when the light-emitting device is emitting light and reflects the detection results to the driver device.Type: GrantFiled: November 17, 2006Date of Patent: April 10, 2012Assignee: LG Display Co., Ltd.Inventors: Shinji Takasugi, Osamu Tokuhiro, Kaoru Kusafuka, Yutaka Kuba
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Patent number: 8138998Abstract: A device for controlling an electroluminescent matrix display by successive selection of its lines, including a column control circuit having circuitry capable of placing, at the beginning of the selection of a line, the display column at a precharge voltage based on the operating voltage of the previous line, the column control circuit also having circuitry capable of modifying the precharge voltage according to the difference between luminance instructions of the previous line and those of the selected line.Type: GrantFiled: April 11, 2008Date of Patent: March 20, 2012Assignee: STMicroelectronics S.A.Inventors: Céline Mas, Corinne Ianigro, Hervé Pierrot
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Patent number: 8130180Abstract: A pixel circuit is disclosed in the present invention, which includes an OLED, a current-driving unit receiving a signal current on a data line during a programming period to provide a corresponding driving current to the OLED, a first switch coupled between the data line and the current-driving unit and turned on during the programming period to conduct the signal current, and a constant current unit providing a constant current on the data line during a pre-programming period and the programming period. The present invention also discloses an apparatus for driving a display, including a scan-driving circuit, a data-driving circuit, and plural constant current units. A method for driving a pixel having an OLED is also disclosed, which includes the steps of receiving a signal current on a data line during a programming period to provide a corresponding driving current to the OLED, and providing a constant current on the data line during a pre-programming period and the programming period.Type: GrantFiled: January 9, 2007Date of Patent: March 6, 2012Assignee: Himax Technologies LimitedInventors: Chen Yu Wang, Yu Wen Chiou
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Patent number: 8130182Abstract: 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: GrantFiled: December 18, 2008Date of Patent: March 6, 2012Assignee: Global OLED Technology LLCInventors: Charles I. Levey, Felipe A. Leon, John W. Hamer, Gary Parrett, Christopher J. White
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Patent number: 8130181Abstract: A OLED display and a driving method thereof are disclosed.Type: GrantFiled: December 15, 2008Date of Patent: March 6, 2012Assignee: LG Display Co., Ltd.Inventors: Chang Hoon Jeon, Jung Chul Kim, Ho Young Lee
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Patent number: 8130178Abstract: In a display apparatus including a switching transistor, 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: July 20, 2011Date of Patent: March 6, 2012Assignee: Sony CorporationInventors: Junichi Yamashita, Masatsugu Tomida, Katsuhide Uchino
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Patent number: 8115707Abstract: A system and method for driving an AMOLED display is provided. The AMOLED display includes a plurality of pixel circuits. A voltage-programming scheme, a current-programming scheme or a combination thereof is applied to drive the display. Threshold shift information, and/or voltage necessary to obtain hybrid driving circuit may be acquired. A data sampling may be implemented to acquire a current/voltage relationship. A feedback operation may be implemented to correct the brightness of the pixel.Type: GrantFiled: June 28, 2005Date of Patent: February 14, 2012Assignee: Ignis Innovation Inc.Inventors: Arokia Nathan, Rick Huang, Stefan Alexander
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Publication number: 20120026146Abstract: A pixel to compensate for the deterioration of an organic light emitting diode, the pixel including an organic light emitting diode; a pixel circuit including a driving transistor controlling an amount of current supplied to the organic light emitting diode; and a compensator compensating for the deterioration of the organic light emitting diode by using on-voltage applied when current flows in the organic light emitting diode and off-voltage applied when current does not flow in the organic light emitting diode; wherein the compensator includes: a compensating capacitor having a second terminal connected to a gate electrode of the driving transistor; and a first compensating transistor connected between a first terminal of the compensating capacitor and an anode electrode of the organic light emitting diode.Type: ApplicationFiled: January 12, 2011Publication date: February 2, 2012Applicant: Samsung Mobile Display Co., Ltd.Inventor: Yang-Wan KIM
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Patent number: 8094094Abstract: 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 discharging circuit. The data lines are disposed in a first direction. 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 respectively a first data line and a second data line of the data lines to a first discharge voltage and a second discharge voltage during a first sub-discharging time of a discharging time, and couple the first data line to the second data line during a second sub-discharging time of the discharging time. Here, the second discharge voltage has different magnitude from the first discharge voltage.Type: GrantFiled: October 5, 2006Date of Patent: January 10, 2012Assignee: LG Display Co., Ltd.Inventor: Ji Hun Kim
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Patent number: 8063857Abstract: When an organic EL display apparatus enables display of a standard luminance mode and a high luminance mode, it takes long time to reset the gate potential of the OLED drive TFT to a given value in a standard mode. In the reset operation of the gate potential of an OLED drive TFT at the time of writing an image signal, in a standard mode, a precharge current is allowed to flow in the OLED element for a short period before the reset operation to set an initial value of the gate potential of the OLED drive TFT to be close to a supply potential or a reference potential. With the above operation, the variation of the OLED drive TFT gate potential after resetting is reduced. As a result, the light emitting period during one frame can be extended. Also, since a blanking period can be extended, it is possible to measure the characteristic of the OLED element by using the blanking period.Type: GrantFiled: December 21, 2007Date of Patent: November 22, 2011Assignee: Hitachi Displays, Ltd.Inventors: Tohru Kohno, Mitsuhide Miyamoto, Hajime Akimoto
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Publication number: 20110279488Abstract: 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: ApplicationFiled: July 11, 2011Publication date: November 17, 2011Applicant: Ignis Innovation Inc.Inventors: Arokia Nathan, Gholamreza Chaji
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Patent number: 8055072Abstract: The invention provides image display panels. The image display panel comprises a histogram generator, a tone slope generator, and an image transformer. The histogram generator receives an original image, counts the pixels of different gray levels to generate a histogram distribution of the original image, and compares the pixel counts at every gray level with a first threshold count to identify the peaks of the histogram distribution. The tone slope generator generates a tone slope based on the histogram distribution and peaks of the histogram distribution. The image transformer transforms the original image into a modified image based on the tone slope.Type: GrantFiled: November 27, 2007Date of Patent: November 8, 2011Assignee: Himax Technologies LimitedInventors: Shing-Chia Chen, Ling-Hsiu Huang
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Patent number: 8044984Abstract: A method for driving an organic light emitting display (OLED) panel having a plurality of organic light emitting diodes is provided. The organic light emitting diodes are coupled to a plurality of segment lines and a plurality of common lines in a matrix structure. The organic light emitting diodes coupled to the same common lines are divided into a plurality of groups according to colors of the OLED panel. Driving currents are provided to the organic light emitting diodes of the groups according to a plurality of pulse width modulation (PWM) manners. The PWM manners generate waveforms having pulse width corresponding to grayscale in a period, wherein each PWM manner corresponds to different colors of the OLED panel.Type: GrantFiled: March 27, 2008Date of Patent: October 25, 2011Assignee: Himax Technologies LimitedInventors: Kuo-Tung Hsu, Wei-Jen Chang
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Patent number: 8044891Abstract: Systems and methods for providing threshold voltage compensation of pixels are provided. A representative system incorporates first switching element and a voltage compensation driver. The first switching element is operative to transfer a data signal. The voltage compensation driver is operative to generate a compensation voltage according to a reference signal and output a driving current according to the data signal and the compensation voltage.Type: GrantFiled: August 5, 2005Date of Patent: October 25, 2011Assignee: Chimei Innolux CorporationInventor: Du-Zen Peng
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Patent number: 8035584Abstract: An organic light emitting display and an image compensation method improves the Long Range Uniformity (LRU) of the output image by displaying the identical image when the identical image is input to each pixel, by measuring the luminance, chromaticity coordinates and color temperature after an organic light emitting display panel is fabricated, by storing the compensation values thereof in a memory in the form of a look-up table in advance, and by compensating one of a power supply voltage, a data voltage and a light emission time.Type: GrantFiled: April 23, 2007Date of Patent: October 11, 2011Assignee: Samsung Mobile Display Co., Ltd.Inventor: Jin-Woung Jung
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Patent number: RE43354Abstract: A driving circuit for an electro-luminescence (EL) cell includes an EL cell, and a supply circuit selectively applying current to the EL cell based on a pixel signal from a data line. A control circuit controls current flow from the supplying circuit to the EL cell such that an amount of current for discriminating between gray scale levels is approximately tens of micro-amps.Type: GrantFiled: April 30, 2004Date of Patent: May 8, 2012Assignee: LG Display Co., Ltd.Inventor: Sung Joon Bae