WO2005101267A2 - Low power circuits for active matrix emissive displays and methods of operating the same - Google Patents
Low power circuits for active matrix emissive displays and methods of operating the same Download PDFInfo
- Publication number
- WO2005101267A2 WO2005101267A2 PCT/US2005/011994 US2005011994W WO2005101267A2 WO 2005101267 A2 WO2005101267 A2 WO 2005101267A2 US 2005011994 W US2005011994 W US 2005011994W WO 2005101267 A2 WO2005101267 A2 WO 2005101267A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- light
- emitting device
- voltage
- display
- pixel
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
- G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
- G09G3/3208—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
- G09G3/3225—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
- G09G3/3233—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix with pixel circuitry controlling the current through the light-emitting element
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
- G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
- G09G3/3208—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
- G09G3/3275—Details of drivers for data electrodes
- G09G3/3291—Details of drivers for data electrodes in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2300/00—Aspects of the constitution of display devices
- G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
- G09G2300/0809—Several active elements per pixel in active matrix panels
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2300/00—Aspects of the constitution of display devices
- G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
- G09G2300/0809—Several active elements per pixel in active matrix panels
- G09G2300/0819—Several active elements per pixel in active matrix panels used for counteracting undesired variations, e.g. feedback or autozeroing
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2300/00—Aspects of the constitution of display devices
- G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
- G09G2300/0809—Several active elements per pixel in active matrix panels
- G09G2300/0842—Several active elements per pixel in active matrix panels forming a memory circuit, e.g. a dynamic memory with one capacitor
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
- G09G2310/0243—Details of the generation of driving signals
- G09G2310/0259—Details of the generation of driving signals with use of an analog or digital ramp generator in the column driver or in the pixel circuit
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
- G09G2310/0264—Details of driving circuits
- G09G2310/027—Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/06—Details of flat display driving waveforms
- G09G2310/066—Waveforms comprising a gently increasing or decreasing portion, e.g. ramp
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0285—Improving the quality of display appearance using tables for spatial correction of display data
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/02—Improving the quality of display appearance
- G09G2320/029—Improving the quality of display appearance by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
- G09G2320/0295—Improving the quality of display appearance by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel by monitoring each display pixel
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/04—Maintaining the quality of display appearance
- G09G2320/043—Preventing or counteracting the effects of ageing
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
- G09G2330/02—Details of power systems and of start or stop of display operation
- G09G2330/021—Power management, e.g. power saving
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2360/00—Aspects of the architecture of display systems
- G09G2360/14—Detecting light within display terminals, e.g. using a single or a plurality of photosensors
- G09G2360/145—Detecting light within display terminals, e.g. using a single or a plurality of photosensors the light originating from the display screen
- G09G2360/147—Detecting light within display terminals, e.g. using a single or a plurality of photosensors the light originating from the display screen the originated light output being determined for each pixel
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2360/00—Aspects of the architecture of display systems
- G09G2360/14—Detecting light within display terminals, e.g. using a single or a plurality of photosensors
- G09G2360/145—Detecting light within display terminals, e.g. using a single or a plurality of photosensors the light originating from the display screen
- G09G2360/147—Detecting light within display terminals, e.g. using a single or a plurality of photosensors the light originating from the display screen the originated light output being determined for each pixel
- G09G2360/148—Detecting light within display terminals, e.g. using a single or a plurality of photosensors the light originating from the display screen the originated light output being determined for each pixel the light being detected by light detection means within each pixel
Definitions
- the present application is related to commonly assigned US Patent Application Attorney Docket Number 186351/US/2/RMA/JJZ (474125-35), entitled “Color Filter integrated with Sensor Array for Flat Panel Display,” filed April 6, 2005, commonly assigned US Patent Application Serial Number 10/872,344, entitled “Method and Apparatus for Controlling an Active Matrix Display,” filed June 17, 2004, and commonly assigned US Patent Application Serial Number 10/841,198 entitled “Method and Apparatus for Controlling Pixel Emission,” filed May 6, 2004, each of which is incorporated herein by reference.
- FIELD OF THE INVENTION [003]
- the present invention relates to active matrix emissive displays and particularly to low power circuits for active matrix emissive displays and methods of operating the same.
- the active matrix display employs a thin film circuit at each pixel that allows each pixel in the display to be directly addressed, hi a typical active matrix liquid crystal display (AMLCD), each pixel circuit includes a data thin film transistor (TFT) TI connected between a data line V data and a liquid crystal display cell LCD and storage capacitor C pair, as shown in FIG. 1.
- the thin film transistor has a control gate Gl connected to an enable voltage V enab i e - During operation, a data voltage V ata is placed on drain D of transistor TI and, when gate Gl is activated, data voltage Vdata is transferred to storage capacitor C and liquid crystal cell LCD though TFT TI.
- the power dissipated during the charging of capacitor C and liquid crystal display cell LCD is usually negligible.
- the power problem in the AMLCD is typically in a backlight circuit that supplies the light, which the LCD modulates.
- active matrix emissive displays particularly the active matrix organic light emitting displays (AMOLED)
- significant amount of power is consumed to produce light emissions from the pixels, and additional power is required to operate driving circuits in the active matrix, which control the light emissions.
- a typical driving circuit of an organic light-emitting diode (OLED) active matrix emissive display includes an OLED Dl and a power TFT T2 serially coupled with each other between a voltage supply V DD and ground.
- TFT T2 has a source S connected to OLED Dl, a drain D connected to voltage supply V DD , and a gate G2 connected to TFT TI.
- Capacitor C is coupled between the source S and gate G2 of TFT T2.
- OLED Dl has parasitic resistor R D and parasitic capacitor Co- TFT T2 supplies current I D to OLED Dl.
- the level of emissions from OLED Dl is proportional to the current L Since the voltage across TFT T2 and OLED Dl is equal to V DD , the power P dissipated by TFT T2 and OLED Dl is equal to V DD times the current I D - While the voltage supply V DD is divided between TFT T2 and OLED Dl, the same current I D flows through both. Therefore, the power P is divided between TFT T2 and OLED Dl in proportion to the voltage V DD being divided between them.
- TFT T2 In order to faithfully convert data voltage V data to a specified current I D and a specified luminance of OLED Dl corresponding to V d ta , changes in the load of TFT T2 due to changes in the luminance of OLED Dl should not cause changes in current I D output from TFT T2. That is, TFT T2 should act as a current source and not change current output as the load changes. In order for TFT T2 to act as a current source, voltage V D across TFT T2 must bias TFT T2 in the saturation mode. As shown in
- the saturation mode corresponds to the flat part of each I D versus V D curve, while the steep slope leading up to the flat part corresponds to the unsaturated mode.
- VQ is the voltage on gate G of TFT T2
- Eq. 1 ⁇ . ° ⁇ "t 2 V d V ,, -v.)'
- ⁇ , ⁇ 0 , ⁇ r , w, 1, d, and V th are parameters associated with TFT T2.
- ⁇ being the effective electron mobility
- ⁇ 0 being the permittivity of free space
- ⁇ r being the dielectric constant of the gate dielectric
- w being the TFT channel width
- 1 being the TFT channel length
- d being the gate dielectric thickness
- V th being the threshold voltage.
- VD must be greater than VQ - V th .
- a larger voltage across the OLED is needed to pass 1 ⁇ A of current through the OLED as the OLED ages. For example, when an OLED is new, only about 4 V across the OLED is required to pass 1 ⁇ A of current, but as it ages this voltage may increase to as high as 6 volts. This means that 2 extra volts should typically be added to V DD to ensure that TFT T2 stays in saturation over the lifetime of the display.
- V D the total required voltage V D is about 5.2 V for an ideal case when 1 ⁇ A of drain current is generated in the saturation mode, plus about 2 volts for threshold voltage drift and about an additional 2 volts for OLED aging and maximum OLED brightness. This means that V DD needs to be as high as about 13.2 volts.
- Each pixel comprises a light-emitting device configured to emit light or photons in response to a current flowing through the light-emitting device.
- the luminance of the light-emitting device depends on the current through the light-emitting device.
- Each pixel further comprises a transistor coupled to the light-emitting device and configured to provide the current through the light-emitting device, the current increasing with a ramp voltage applied to a control terminal of the transistor, and a switching device configured to switch off in response to the luminance of the light-emitting device having reached a specified level, thereby disconnecting the ramp voltage from the transistor and locking the brightness at the specified level.
- the switching device is further configured to stay off thereby allowing the luminance of the light-emitting device to be kept at the specified level until the pixel is rewritten in the next frame.
- the transistor and the light-emitting device are serially coupled with each other between a variable voltage source and ground.
- the variable voltage source is configured to output a voltage that changes as the display ages.
- the voltage output from the variable voltage source changes based on a statistical evaluation of the changes in ramp voltages required to cause the light from the light-emitting devices to reach specified levels in brightness in some or all of the pixels in the display.
- the embodiments of the present invention also provide a method for controlling the brightness of a pixel in a display.
- the method comprises switching on a switching device by applying a first control voltage to a first control terminal and a second control voltage to a second control terminal of the switching device, and applying a ramp voltage through the switching device to a gate of a transistor serially coupled with the light-emitting device thereby causing light emitted from the light-emitting device to increase in brightness with the ramp voltage.
- the light from the light-emitting device illuminates an optical sensor thereby causing an electrical parameter associated with the optical sensor to change as the light changes in brightness, and the second control voltage is dependent on the electrical parameter and changes to a different value in response to the luminance of the light-emitting device having reached a specified brightness for the pixel, thereby switching off the switching device.
- the transistor and the light-emitting device are serially coupled with each other between a variable voltage source and ground, and the method further comprises varying a voltage output from the variable voltage source as the display ages.
- the voltage output is varied by recording a value of ramp voltage required to cause the light-emitting device in each pixel in the display to reach the specified level of brightness for the pixel, and computing a statistical measure from the changes in the recorded values for some or all of the pixels in the display to determine when and how much to change the voltage output.
- the embodiments described herein provide significant power savings by allowing a power TFT, that supplies currents to a light-emitting device such as an OLED in a pixel of a display, to operation in the unsaturated regions associated with its current- voltage characteristics, because the brightness of the light-emitting device according to embodiments of the present invention does not depend on a current- voltage relationship of the power TFT, but on the pixel brightness itself. Further power savings are achieved in embodiments using variable power supplies.
- FIG. 1 is a diagram illustrating a conventional AMLCD pixel driving circuit.
- FIG. 2 is a circuit schematic illustrating a conventional AMOLED pixel driving circuit.
- FIG. 3 is a graph of drain current versus source-drain voltage in a power TFT.
- FIG. 4A is a block diagram of an emissive feedback circuit in a display according to one embodiment of the present invention.
- FIG. 4B is a block diagram of an emissive feedback circuit in a display having a plurality of pixels according to one embodiment of the present invention.
- FIG. 4C is a block diagram of two separate components in an emissive feedback circuit according to one embodiment of the present invention.
- FIG. 5 is a schematic diagram of a portion of a display circuit according to one embodiment of the present invention.
- FIG. 6 is a diagram of a larger portion of the display circuit according to an embodiment of the present invention.
- FIG. 7 is a diagram illustrating a power adjustment unit in the display circuit according to further embodiments of the present invention.
- Embodiments of the present invention provide low-power circuits for emissive displays and methods of operating the same.
- the embodiments described herein save power consumed by power TFTs that supply currents to light-emitting devices in a display by allowing the power TFTs to operate in the unsaturated region.
- Sensor 130 may comprise any sensor material having a measurable property, such as a resistance, capacitance, inductance, etc., dependent on received emissions.
- sensor 130 comprises a photosensitive resistor whose resistance varies with an incident photon flux.
- the sensor 130 comprises a calibrated photon flux integrator, such as the one disclosed in commonly assigned US Patent Application Serial Number 11/016,372 entitled “Active-Matrix Display and Pixel Structure for Feedback Stabilized Flat Panel Display,” filed on December 17, 2004, which is incorporated herein by reference in its entirety.
- Sensor 130 may also or alternatively comprise one or more of other radiation-sensitive sensors including, but not limited to, optical diodes and/or optical transistors.
- sensor 130 may comprise at least one type of material that has one or more electrical properties changing according to the intensity of radiation falling or impinging on a surface of the material.
- materials include but are not limited to amorphous silicon (a-Si), cadmium selenide (CdSe), silicon (Si), and Selenium (Se).
- Sensor 130 may also comprise other circuit elements such as an isolation transistor for preventing cross talk among a plurality of sensors 130 in an active matrix display, as discussed in more detail below.
- the control unit 140 may be implemented in hardware, software, or a combination thereof. In one embodiment, the control unit 140 is implemented using a voltage comparator. Other comparison circuitry or software may also or alternatively be used.
- the driver 120 may include any hardware, software, firmware, or combinations thereof suitable for providing a drive signal to emission source 110. Driver 120 may be integrated with a display substrate on which the emission source 110 is formed, or it may be separate from the display substrate. In some embodiments, portions of driver 120 are formed on the display substrate.
- data input 150 receives image voltage data corresponding to a desired brightness of the light from emission source 110 and converts the image voltage data to a reference voltage for use by the control unit 140.
- the pixel driver 120 is configured to vary the light emission from the emission source 110 until the electrical parameter in sensor 130 reaches a certain value corresponding to the reference voltage, at which point, control unit 140 couples a control signal to driver 120 to stop the variation of the light emission.
- Driver 120 also comprises mechanisms for maintaining the light emission from emission source 110 at the desired brightness after the variation of the light emission is stopped.
- an electrical measure in the power adjustment unit is also varied accordingly, and the control signal from the control unit 140 is also coupled to the power adjustment unit 160 to stop the variation of the electrical measure.
- the power adjustment unit 160 determines whether to adjust the variable power supply 170 and how much adjustment needs to be done using, for example, a statistical technique, as explained in more detail below.
- FIG. 5 illustrates one implementation of the display circuit 100 in the embodiments of FIG. 4A.
- display circuit 100 comprises a transistor 512 and a light-emitting device 514 as the light emission source 110.
- Display circuit 100 further comprises a switching device 522 and a capacitor 524 as part of the driver 120, an optical sensor (OS) 530 and an optional isolation device 532 as sensor 130, and a voltage divider resistor 542 and a comparator 544 as part of the control unit 140.
- the OS 530 is coupled to a line selector output voltage Vosi and the voltage divider resistor 542 is coupled with OS 530 between Vosi and ground.
- the comparator 544 has a first input PI coupled to the data input unit, a second input P2 coupled to a circuit node 546 between the OS 530 and the voltage divider resistor 542, and an output P3.
- the switching device 522 has a first control terminal Gla coupled to Vosi, a second control terminal Gib coupled to the output P3 of comparator 544, an input DRl coupled to a ramp voltage output VR, and an output S2 coupled to a control terminal G2 of transistor 512.
- the capacitor 524 is coupled between the control terminal G2 and a circuit node S2 between transistor 512 and light- emitting device 514. The capacitor 524 may alternatively be coupled between control terminal G2 of transistor 512 and ground.
- Each OS 530 can be any suitable sensor having a measurable property, such as a resistance, capacitance, inductance, or the like parameter, property, or characteristic, dependent on received emissions.
- An example of OS 230 is a photosensitive resistor whose resistance varies with an incident photon flux.
- each OS 230 is a calibrated photon flux integrator, such as the one disclosed in commonly assigned US Patent Application Serial Number 11/016372 entitled “Active-Matrix Display and Pixel Structure for Feedback Stabilized Flat Panel Display,” filed on December 17, 2004, which application is incorporated herein by reference in its entirety.
- each OS 230 may include at least one type of material that has one or more electrical properties changing according to the intensity of radiation falling or impinging on a surface of the material.
- Such materials include but are not limited to amorphous silicon (a-Si), cadmium selenide (CdSe), silicon (Si), and Selenium (Se).
- a-Si amorphous silicon
- CdSe cadmium selenide
- Si silicon
- Se Selenium
- Other radiation- sensitive sensors may also or alternatively be used including, but not limited to, optical diodes, and/or optical transistors.
- Isolation device 532 such as an isolation transistor may be provided to isolate the optical sensors 530.
- Isolation transistor 532 can be any type of transistor having first and second terminals and a control terminal, with conductivity between the first and second terminals controllable by a control voltage applied to the control terminal.
- isolation transistor 532 is a TFT with the first terminal being a drain DR3, the second terminal being a source S3, and the control terminal being a gate G3.
- the isolation transistor 532 is serially coupled with OS 530 between Vosi and ground, with the control terminal of G3 connected to Vosi, while the first and second terminals are connected to resistor 542 and OS 530, respectively, or to OS 530 and Vosi, respectively.
- OS 530 and isolation transistor 532 may together be referred to as sensor 130.
- Light-emitting device 514 may generally be any light-emitting device known in the art that produces radiation such as light emissions in response to an electrical measure such as an electrical current through the device or an electrical voltage across the device.
- Examples of light-emitting device 514 include but are not limited to light emitting diodes (LED) and organic light emitting diodes (OLED) that emit light at any wavelength or a plurality of wavelengths.
- Other light-emitting devices may be used including electroluminescent cells, inorganic light emitting diodes, and those used in vacuum florescent displays, field emission displays and plasma displays. In one embodiment, an OLED is used as the light-emitting device 514.
- Light-emitting device 514 is sometimes referred to as an OLED 514 hereafter. But it will be appreciated that the invention is not limited to using an OLED as the light-emitting device 514. Furthermore, although the invention is sometimes described relative to a flat panel display, it will be appreciated that many aspects of the embodiments described herein are applicable to a display that is not flat or built as a panel.
- Transistor 512 can be any type of transistor having a first terminal, a second terminal, and a control terminal, with the current between the first and second terminals dependent on a control voltage applied to the control terminal.
- transistor 512 is a TFT with the first terminal being a drain D2, the second terminal being a source S2, and the control terminal being a gate G2.
- Transistor 512 and light-emitting device 514 are serially coupled between a power supply V DD and ground, with the first terminal of transistor 512 connected to V DD , the second terminal of transistor 512 connected to the light-emitting device 514, and the control terminal connected to ramp voltage output VR through switching device 522.
- switching device 522 is a double-gated TFT, that is, a TFT with a single channel but two gates Gla and Gib.
- the double gates act like an AND function in logic, because for the TFT 522 to conduct, logic highs need to be simultaneously applied to both gates.
- a double-gated TFT is preferred, any switching device implementing the AND function in logic is suitable for use as the switching device 522.
- two serially coupled TFTs or other types of transistors maybe used as the switching device 522.
- Use of a double-gated TFT or other device implementing the AND function in logic as the switching device 522 helps to reduce cross talk between pixels, as explained in more detail below.
- display 100 comprises a plurality of pixels 115 each having a driver 120 and a emission source 120, and a plurality of sensors 130 each corresponding to a pixel, as shown in FIG. 4B.
- Display 100 further comprises a column control circuit 44 and a row control circuit 46.
- Each pixel 115 is coupled to the column control circuit 44 via a column line 55 and to the row control circuit 46 via a row line 56.
- Each sensor 130 is coupled to the row control circuit 46 via a sensor row line 70 and to the column control circuit 44 via a sensor column line 71.
- at least parts of the control unit 140, the data input unit 150 and the power adjustment unit 160 are comprised in the column control circuit 44.
- each sensor 130 is associated with a respective pixel 115 and is positioned to receive a portion of the light emitted from the pixel.
- Pixels are generally square, as shown in FIG. 4B, but can be any shape such as rectangular, round, oval, hexagonal, polygonal, or any other shape.
- display 11 is a color display
- pixel 33 can also be subpixels organized in groups, each group corresponding to a pixel. The subpixels in a group should include a number (e.g., 3) of subpixels each occupying a portion of the area designated for the corresponding pixel.
- each pixel is in the shape of a square
- the subpixels are generally as high as the pixel, but only a fraction (e.g., 1/3) of the width of the square.
- Subpixels may be identically sized or shaped, or they may have different sizes and shapes.
- Each subpixel may include the same circuit elements as pixel 115 and the sub-pixels in a display can be interconnected with each other and to the column and row control circuits 44 and 46 just as the pixels 115 shown in FIG. 4B.
- a sensor 130 is associated with each subpixel.
- the reference of a pixel can mean both a pixel or subpixel.
- the row control circuit 46 is configured to activate a selected row of sensors 60 by, for example, raising a voltage on a selected sensor row line 70, which couples the selected row of sensors to the row control circuit 46.
- the column control circuit 44 is configured to detect changes in the electrical parameters associated with the selected row of sensors and to control the luminance of the corresponding row of pixels 115 based on the changes in the electrical parameters. This way, the luminance of each pixel can be controlled at a specified level based on feedbacks from the sensors 130.
- the sensors 130 may be used for purposes other than or in addition to feedback control of the pixel luminance, and there may be more or less sensors 130 than the pixels or subpixels 115 in a display.
- display 100 comprises a sensor component 100 and a display component 110, as illustrated in FIG. 4C.
- the display component 110 comprises pixels 115, the column control circuit 44, the row control circuit 46, the column lines 55, and the row lines 56 formed on a first substrate 112, while the sensor component 100 comprises the sensors 130, the sensor row lines 70, and the sensor column lines 71 formed on a second substrate 102.
- the sensor component 100 may also comprise color filter elements 20, 30, and 40 when the sensors 130 are integrated with a color filter for the display, as described in related Patent Application Attorney Docket Number 186351/US/2/RMA/JJZ (474125-35).
- electrical contact pads or pins 114 on display component 110 are mated with electrical contact pads 104 on filter/sensor plate 100, as indicated by the dotted line aa, in order to connect the sensor row lines 70 to the row control circuit 46.
- electrical contact pads or pins 116 on display component 110 are mated with electrical contact pads 106 on filter/sensor plate 100, as indicated by the dotted line bb, in order to connect the sensor column lines 71 to the column control circuit 44.
- display component 110 can be one of any type of displays including but not limited to LCDs, electroluminescent displays, plasma displays, LEDs, OLED based displays, micro electrical mechanical systems (MEMS) based displays, such as the Digital Light projectors, and the like.
- LCDs liquid crystal display
- electroluminescent displays plasma displays
- LEDs OLED based displays
- MEMS micro electrical mechanical systems
- display component 110 may comprise another set of row lines connecting each pixel 33 to a respective one of the contact pads 114.
- display 100 comprises a plurality of pixels 500 arranged in rows and columns, with pixels PIX1,1, PIX1,2, etc., in row 1, pixels PLX2,1, PIX2,2, etc., in row 2, and so on for the other rows in the display.
- Each pixel 500 comprises a transistor 512, a light-emitting device 514, a switching device 522, and a capacitor 524.
- FIG. 6 also shows a sensor array comprising a plurality of sensors arranged in rows and columns, each corresponding to a pixel and each comprising an optical sensor OS 530 and an isolation transistor 532.
- display 100 further comprises ramp selector (RS) 610 configured to receive a ramp voltage VR and to select one of row lines, VR1, VR2, etc., to output the ramp voltage VR.
- RS ramp selector
- Each of lines VR1, VR2, etc. is connected to drain Dl of switching device 522 in each of a corresponding row of pixels 500.
- Circuit 100 further comprises a line selector (VosS) configured to receive a line select voltage Vos and to select one of sensor row lines, Vosi, Vos2, etc., to output the line select voltage Vos-
- RS 610 and VosS 620 are part of the row control circuit 46 and can be implemented using shift registers.
- Each sensor comprising the OS 530 and the TFT 532 may be part of a pixel in the display and formed on a same substrate the pixels are formed. Alternatively, the sensors are fabricated on a different substrate from the substrate on which the pixels are formed, as shown in FIG. 4C. In this case, another set or row lines (not shown) are provided to allow gate Gla to be connected to contact pads 114 and thus to the sensor row lines Vosi, Vos2, etc., when the two substrates are mated together.
- FIG. 6 also shows that display comprises a plurality of comparators 544 and resistors 522 each being associated with a column of pixels 500.
- FIG. 6 further shows a block diagram of data input unit 150, which comprises an analog to digital converter (A D) 630 configured to convert a received image voltage data to a corresponding digital value, an optional grayscale level calculator (GL) 631 coupled to the A/D 630 and configured to generate a grayscale level corresponding to the digital value, a row and column tracker unit (RCNT) 632 configured to generate a line number and column number for the image voltage data, a calibration look-up table addresser (LA) 633 coupled to the RCNT 632 and configured to output an address in the display circuit 100 corresponding to the line number and column number, and a first look-up table (LUT1) 635 coupled to the GL 631 and the LA 633.
- a D analog to digital converter
- GL grayscale level calculator
- RCNT row and column tracker unit
- LA calibration look-up table addresser
- Data input unit 150 further comprises a digital to analog converter (DAC) 636 coupled to the LUT1 635 and a first line buffer (LBl) 637 coupled to the DAC 636.
- DAC digital to analog converter
- LBl first line buffer
- comparators 544, resistors 522, and at least part of data input unit 150 are included in the column control circuit 44.
- LUT1 635 stores calibration data obtained during a calibration process for calibrating against a light source having a known luminance each optical sensor in the display circuit 100.
- the calibration process results in a voltage divider voltage level at circuit node 546 in each pixel for each grayscale level.
- an 8- bit grayscale has 0 - 256 levels of luminance with the 255 th level being at a chosen level, such as 300 nits for a Television screen.
- the luminance level for each of the remaining 255 levels is assigned according to the logarithmic response of the human eye.
- the zero level corresponds to no emission.
- Each value of brightness will produce a specific voltage on the circuit node 546 between optical sensor OS 530 and voltage divider resistor 542.
- These voltage values are stored in lookup table LUT1 as the calibration data.
- the LUT1 635 based on the address provided by LA 633 and the gray scale level provided by GL 631, the LUT1 635 generates a calibrated voltage from the stored calibration data and provides the calibrated voltage to DAC 636, which converts the calibrated voltage into an analog voltage value and downloads the analog voltage value to LBl 637.
- LBl 637 provides the analog voltage value as a reference voltage to input PI of comparator 544 associated with the column corresponding to the address.
- comparator 544 is a voltage comparator that compares the voltage levels at its two inputs PI and P2 and generates at its output P3 a positive supply rail (e.g., +10 volts) when PI is larger than P2 and a negative supply rail (e.g., 0 volts) when PI is equal of less than P2.
- the positive supply rail corresponds to a logic high for the switching device 522 while negative supply rail corresponds to a logic low for the switching device 522.
- OS 530 has a maximum resistance to current flow; and voltage on input pin P2 of VC 544 is minimum because the resistance R of voltage divider resistor 542 is small compared to the resistance of OS 530.
- Image data voltages for row 1 of the display 100 are sent to the A/D converter 630 serially and each is converted to a reference voltage and stored in LBl 637 until LBl stores the reference voltages for every pixel in the row.
- shift register Vos 620 sends the Vos voltage (e.g., +10 volts) to line Vosi, turning on gate Gib of each switching device 524 in row 1, and thus, the switching devices 522 themselves (since gate Gla is already on).
- the voltage Vos on line Vosi is also applied to OS 530 and to the gate G3 of transistor 532 in each of the first row of pixels, causing transistor 532 to conduct and current to flow through OS 530.
- shift register RS 610 sends the ramp voltage VR (e.g., from 0 to 10 volts) to line VRl, which ramp voltage is applied to storage capacitor 524 and to the gate G2 of transistor 512 in each pixel in row 1 because switching device 522 is conducting.
- VR ramp voltage
- the capacitor 524 is increasingly charged, the current through transistor 512 and OLED 514 in each of the first row of pixels increases, and the light emission from the OLED also increases.
- the increasing light emission from the OLED 514 in each pixel in row 1 falls on OS 530 associated with the pixel and causes the resistance associated with the OS 530 to decrease, and thus, the voltage across resistor 542 or the voltage at input P2 of comparator 544 to increase.
- the duration of time that the ramp voltage VRl takes to increase to its full value is called the line address time.
- the line address time In a display having 500 lines and running at 60 frames per second, the line address time is approximately 33 micro seconds or shorter. Therefore, all the pixels in the first row are at their respective desired emission levels by the end of the line address time. And this completes the writing of row 1 in the display 100.
- both horizontal shift registers, VosS 620 and RS 610 turn off lines VRl and Vosi, respectively, causing switching device 522 and isolation transistor 532 to be turned off, thereby, locking the voltage on the storage capacitor 524 and isolating the optical sensors 530 in row 1 from the voltage comparators 544 associated with each column.
- each switching device 522 has double gates, Gate Gla and Gate Gib, and gate Gla of each switching device 522 in row 1 is held by line Vosi- So, during the writing of subsequent rows, while gate Gib may conduct, the switching devices 522 in row 1 are kept off because Vosi is not selected.
- capacitor 524 in each pixel in row 1 is kept disconnected from the capacitors 524 in the other pixels in rowl. This eliminates cross talk between capacitors 524 in different pixels in the row that has just be written, so that each pixel in the row continues to output the desired emission level during the writing of subsequent rows.
- each pixel 500 in the display 100 does not depend on a voltage- current relationship associated with transistor 512, but is controlled by a specified image grayscale level and a feedback of the pixel luminance itself, the embodiments described above allow transistor 512 to operate in the unsaturated region, and thus, save power for the operation of display 100.
- a V DD as low as 9 volts may be sufficient to operate display 100 because transistor TFT 512 does not need to operate in saturation mode.
- the maximum gate voltage VQ 2 for a typical power TFT 512 to operate in the unsaturated region at 1 ⁇ A current should be about 15 volts.
- the maximum value in ramp voltage VR should be set above 15 V.
- TFT 512 is higher when TFT 512 is operating in the unsaturated region, but this does not create a significant power dissipation issue.
- additional voltages or voltage range capacity may advantageously be included in the power supply V DD to allow for degradation in the efficiency of the OLED Dl and for threshold voltage drift in power TFT 512.
- These additional voltages may amount to as much as three to four volts, which results in significant power dissipation. Further savings in power can be attained by using a variable power supply, which allows the voltage V DD to be set low initially and be increased as pixels age, or threshold voltage drifts, or both.
- FIG. 7 illustrates the power adjustment unit 160 in display 100 according to one embodiment of the present invention.
- power adjustment unit 160 comprises a plurality of transistors 710 each associated with a column of pixels and a plurality of capacitors 712 each coupled to a respective one of the transistors 710.
- Each fransistor 710 can be any fransistor having first and second terminals and a control terminal, with the conductivity between first and second terminals controllable by a voltage applied to the control terminal.
- each transistor 710 is a TFT with the first terminal being the drain D4, the second terminal being the source D4, and the control terminal being the gate G4 of the TFT.
- Each capacitor 712 is coupled between a source S4 of a respective one of the TFTs 710 and ground.
- the gate G4 of each TFT 710 is connected to output P3 of a respective one of the voltage comparators 544, and the drain D4 of the TFT is connected to the ramp voltage output VR.
- Power adjustment unit 160 further comprises a line buffer (LB2) 720, a ramp logic block (RL) 730, a storage medium 740 storing therein a look-up table (LUT2), and a storage medium 750 storing therein a differential ramp voltage table (DRV).
- LB2 720 line buffer
- RL ramp logic block
- storage medium 740 storing therein a look-up table (LUT2)
- DUV differential ramp voltage table
- the set of ramp voltages loaded in LB2 720 represent the initial and new state of the display before any pixel degradation or TFT threshold voltage drifts have occurred.
- This initial set of ramp voltages is stored in look up table LU2 740.
- the initial ramp voltage set is guided to look up table LUT2 740 by Ramp logic RL 730.
- the ramp voltages loaded in LB2 are compared to the initial set of ramp voltages stored in lookup table LUT2 and the difference is stored in DRV 750.
- the set of values in DRV 750 represents the aging of the display and these values should increase with the continued usage of display 100.
- V DD output from the variable power supply 170 is also increased using a known technique to compensate for the pixel aging and power TFT threshold voltage drifts.
- V DD can be increased by a certain increment (e.g., 0.25 volts) when a certain percentage (e.g., 20%>) of the differential ramp voltages stored in DRV 750 have each changed by more than a certain amount (e.g., 0.25 volts).
- V DD can be increased by a certain increment (e.g., 0.25 volts) when an average of the differential ramp voltages stored in DRV 750 has increased by a certain amount (e.g., 0.25 volts).
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
- Electroluminescent Light Sources (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2007508403A JP2007534015A (en) | 2004-04-12 | 2005-04-06 | Low power circuit for active matrix light emitting display and method of operating the same |
EP05734209A EP1743313A4 (en) | 2004-04-12 | 2005-04-06 | Low power circuits for active matrix emissive displays and methods of operating the same |
AU2005234023A AU2005234023A1 (en) | 2004-04-12 | 2005-04-06 | Low power circuits for active matrix emissive displays and methods of operating the same |
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US56147404P | 2004-04-12 | 2004-04-12 | |
US60/561,474 | 2004-04-12 | ||
US10/841,198 | 2004-05-06 | ||
US10/841,198 US20040257352A1 (en) | 2003-06-18 | 2004-05-06 | Method and apparatus for controlling |
US10/872,344 US7106285B2 (en) | 2003-06-18 | 2004-06-17 | Method and apparatus for controlling an active matrix display |
US10/872,344 | 2004-06-17 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2005101267A2 true WO2005101267A2 (en) | 2005-10-27 |
WO2005101267A3 WO2005101267A3 (en) | 2005-12-15 |
Family
ID=35150618
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2005/011994 WO2005101267A2 (en) | 2004-04-12 | 2005-04-06 | Low power circuits for active matrix emissive displays and methods of operating the same |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP1743313A4 (en) |
JP (1) | JP2007534015A (en) |
KR (1) | KR20070004970A (en) |
AU (1) | AU2005234023A1 (en) |
WO (1) | WO2005101267A2 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2007129241A3 (en) * | 2006-05-04 | 2008-03-27 | Philips Intellectual Property | Lighting device with an array of controlled emitters with shared control and feedback |
JP2008257201A (en) * | 2007-04-06 | 2008-10-23 | Samsung Sdi Co Ltd | Organic light emitting diode display and method of driving the same |
US8599222B2 (en) | 2008-09-04 | 2013-12-03 | Seiko Epson Corporation | Method of driving pixel circuit, light emitting device, and electronic apparatus |
WO2020042522A1 (en) | 2018-08-30 | 2020-03-05 | Boe Technology Group Co., Ltd. | Display panel and driving method thereof |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100730361B1 (en) * | 2007-01-10 | 2007-06-19 | 실리콘 디스플레이 (주) | Amoled with a built-in image sensor |
JP5374976B2 (en) * | 2008-09-04 | 2013-12-25 | セイコーエプソン株式会社 | Pixel circuit driving method, light emitting device, and electronic apparatus |
JP5439782B2 (en) * | 2008-09-29 | 2014-03-12 | セイコーエプソン株式会社 | Pixel circuit driving method, light emitting device, and electronic apparatus |
JP5401895B2 (en) * | 2008-09-29 | 2014-01-29 | セイコーエプソン株式会社 | Pixel circuit driving method, light emitting device, and electronic apparatus |
JP5458540B2 (en) * | 2008-09-29 | 2014-04-02 | セイコーエプソン株式会社 | Pixel circuit driving method, light emitting device, and electronic apparatus |
JP2022050906A (en) * | 2020-09-18 | 2022-03-31 | ソニーセミコンダクタソリューションズ株式会社 | Display device, driving method for display device, and electronic apparatus |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6249269B1 (en) * | 1998-04-30 | 2001-06-19 | Agilent Technologies, Inc. | Analog pixel drive circuit for an electro-optical material-based display device |
JP2001075524A (en) * | 1999-09-03 | 2001-03-23 | Rohm Co Ltd | Display device |
US20040257352A1 (en) * | 2003-06-18 | 2004-12-23 | Nuelight Corporation | Method and apparatus for controlling |
-
2005
- 2005-04-06 EP EP05734209A patent/EP1743313A4/en not_active Withdrawn
- 2005-04-06 KR KR1020067023781A patent/KR20070004970A/en not_active Application Discontinuation
- 2005-04-06 JP JP2007508403A patent/JP2007534015A/en active Pending
- 2005-04-06 AU AU2005234023A patent/AU2005234023A1/en not_active Abandoned
- 2005-04-06 WO PCT/US2005/011994 patent/WO2005101267A2/en not_active Application Discontinuation
Non-Patent Citations (1)
Title |
---|
See references of EP1743313A4 * |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2007129241A3 (en) * | 2006-05-04 | 2008-03-27 | Philips Intellectual Property | Lighting device with an array of controlled emitters with shared control and feedback |
JP2008257201A (en) * | 2007-04-06 | 2008-10-23 | Samsung Sdi Co Ltd | Organic light emitting diode display and method of driving the same |
US8519921B2 (en) | 2007-04-06 | 2013-08-27 | Samsung Display Co., Ltd. | Organic light emitting diode (OLED) display adjusting for ambient illuminance and a method of driving the same |
US8599222B2 (en) | 2008-09-04 | 2013-12-03 | Seiko Epson Corporation | Method of driving pixel circuit, light emitting device, and electronic apparatus |
US9117399B2 (en) | 2008-09-04 | 2015-08-25 | Seiko Epson Corporation | Method of driving pixel circuit, light emitting device, and electronic apparatus |
WO2020042522A1 (en) | 2018-08-30 | 2020-03-05 | Boe Technology Group Co., Ltd. | Display panel and driving method thereof |
EP3844740A4 (en) * | 2018-08-30 | 2022-05-18 | Boe Technology Group Co., Ltd. | Display panel and driving method thereof |
Also Published As
Publication number | Publication date |
---|---|
JP2007534015A (en) | 2007-11-22 |
WO2005101267A3 (en) | 2005-12-15 |
KR20070004970A (en) | 2007-01-09 |
EP1743313A2 (en) | 2007-01-17 |
AU2005234023A1 (en) | 2005-10-27 |
EP1743313A4 (en) | 2007-05-30 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7129938B2 (en) | Low power circuits for active matrix emissive displays and methods of operating the same | |
US20050248515A1 (en) | Stabilized active matrix emissive display | |
US8373628B2 (en) | Active matrix display devices | |
EP2033177B1 (en) | Active matrix display compensation | |
JP2010511183A (en) | Active matrix display device having optical feedback and driving method thereof | |
US8816943B2 (en) | Display device with compensation for variations in pixel transistors mobility | |
US20080122759A1 (en) | Active matrix display compensating method | |
JP2006525539A (en) | Active matrix OLED display with threshold voltage drift compensation | |
US20080266214A1 (en) | Sub-pixel current measurement for oled display | |
JP2002297097A (en) | Display device and drive method therefor | |
US7537946B2 (en) | Display apparatus | |
US20080231557A1 (en) | Emission control in aged active matrix oled display using voltage ratio or current ratio | |
KR101060450B1 (en) | OLED display device | |
US7579781B2 (en) | Organic electro-luminescent display device and method for driving the same | |
EP1743313A2 (en) | Low power circuits for active matrix emissive displays and methods of operating the same | |
US20080231566A1 (en) | Minimizing dark current in oled display using modified gamma network | |
JP2007524118A (en) | Active matrix display device | |
EP1743321A2 (en) | Color filter integrated with sensor array for flat panel display | |
KR101322171B1 (en) | Organic Light Emitting Diode Display And Driving Method Thereof | |
US20230377494A1 (en) | Display, pixel circuit, and method | |
KR101072757B1 (en) | Driving Circuit of Passive Matrix Organic Electroluminescent Display Device | |
KR20220060457A (en) | Display apparatus | |
KR20040089256A (en) | Method and apparatus for achieving active matrix oled display devices with uniform luminance | |
KR20070031924A (en) | Active matrix display devices |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A2 Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BW BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE EG ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KM KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NA NI NO NZ OM PG PH PL PT RO RU SC SD SE SG SK SL SM SY TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW |
|
AL | Designated countries for regional patents |
Kind code of ref document: A2 Designated state(s): GM KE LS MW MZ NA SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LT LU MC NL PL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
WWE | Wipo information: entry into national phase |
Ref document number: 2007508403 Country of ref document: JP |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
WWW | Wipo information: withdrawn in national office |
Country of ref document: DE |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2005234023 Country of ref document: AU |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2005734209 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 1020067023781 Country of ref document: KR |
|
ENP | Entry into the national phase |
Ref document number: 2005234023 Country of ref document: AU Date of ref document: 20050406 Kind code of ref document: A |
|
WWP | Wipo information: published in national office |
Ref document number: 2005234023 Country of ref document: AU |
|
WWE | Wipo information: entry into national phase |
Ref document number: 200580017541.4 Country of ref document: CN |
|
WWP | Wipo information: published in national office |
Ref document number: 1020067023781 Country of ref document: KR |
|
WWP | Wipo information: published in national office |
Ref document number: 2005734209 Country of ref document: EP |
|
WWW | Wipo information: withdrawn in national office |
Ref document number: 2005734209 Country of ref document: EP |