公开(公告)号：US20210020104A1

公开(公告)日：2021-01-21

申请号：US16515370

申请日：2019-07-18

Applicant: Sharp Kabushiki Kaisha

Inventor： Tong Lu ,  Michael James Brownlow ,  Tim Michael Smeeton

IPC: G09G3/3258 ,  G09G3/3291 ,  G09G3/3266

Abstract: A pixel circuit is operable in initialization, data programming, a threshold compensation, and emission phases. The pixel circuit includes a drive transistor configured to control an amount of current to a light-emitting device during the emission phase depending upon a voltage applied to a gate of the drive transistor. A first ultra-low leakage oxide transistor is employed as a data switch device, and the data voltage is applied to the gate of the drive transistor through the first ultra-low leakage oxide transistor during the data programming phase. A second ultra-low leakage oxide transistor is employed as an initialization switch device. The second ultra-low leakage oxide transistor is in an on state during the initialization, data programming, and threshold compensation phases, and the initialization voltage is applied to the gate of the drive transistor through the second ultra-low leakage oxide transistor during the initialization phase.

公开(公告)号：US20190304370A1

公开(公告)日：2019-10-03

申请号：US15937965

申请日：2018-03-28

Applicant: Sharp Kabushiki Kaisha

Inventor： Tong Lu ,  Michael James Brownlow ,  Tim Michael Smeeton

IPC: G09G3/3258

Abstract: A display system includes a display panel comprising a plurality of pixel circuits, and a measurement and data processing unit that is external to the display panel. Each pixel circuit includes a light-emitting device having a first terminal connected to a first voltage supply and a second terminal opposite from the first terminal; a first transistor connected between a data voltage supply line from the measurement and data processing unit and the second terminal of the light emitting device; and a second transistor connected between the second terminal of the light-emitting device and a sample line to the measurement and data processing unit. The measurement and data processing unit is configured to sample a measured voltage at the second terminal of the light-emitting device through the sample line and to output a data voltage to the light-emitting device based on the measured voltage to compensate variations in properties of the light-emitting device. Each pixel circuit further may include a storage capacitor connected between the second terminal of the light-emitting device and a second voltage supply, wherein the storage capacitor discharges through the light-emitting device when the data voltage is disconnected from the pixel circuit.

公开(公告)号：US20190295467A1

公开(公告)日：2019-09-26

申请号：US15933474

申请日：2018-03-23

Applicant: Sharp Kabushiki Kaisha

Inventor： Tong Lu ,  Christopher James Brown ,  Michael James Brownlow ,  Tim Michael Smeeton

IPC: G09G3/3233 ,  G09G3/3291

Abstract: A pixel circuit for a display device includes a drive transistor configured to control an amount of current to a light-emitting device during an emission phase depending upon a voltage applied to a gate of the drive transistor; a second transistor connected to the gate of the drive transistor, wherein the second transistor is in an on state during a combined programming and compensation phase and in an off state during the emission phase, and when the second transistor is in an on state the drive transistor becomes diode-connected such that a gate and a second terminal of the drive transistor are connected through the second transistor; a third transistor connected to the second terminal of the drive transistor, wherein the third transistor is in an on state during the combined programming and compensation phase to permit a reference current to be applied through the drive transistor, and is in an off state during the emission phase to remove the reference current; and a capacitor having a first plate that is connected to the gate of the drive transistor and a second plate that is connectable to a data voltage during the combined programming and compensation phase. A threshold voltage and/or a carrier mobility of the drive transistor is compensated by application of the reference current during the combined programming and compensation phase.

公开(公告)号：US11189225B1

公开(公告)日：2021-11-30

申请号：US17029696

申请日：2020-09-23

Applicant: Sharp Kabushiki Kaisha

Inventor： Adnan Heganovic ,  Tong Lu

IPC: G09G3/3233 ,  G09G3/3266 ,  G09G3/3291

Abstract: A pixel circuit that drives a light-emitting device employs a diode-connection compensation scheme that compensates for threshold variations of the diode connecting switch that diode connects the drive transistor during a threshold compensation phase. The pixel circuit operates to reduce the impact of threshold voltage variations of the diode connecting switch to improve brightness uniformity and picture quality. The pixel circuit includes two compensation capacitors in addition to the storage capacitor for data programming to control the flow and magnitude of a rebalancing current through the diode connecting switch in such a way to cancel excess or deficit of charge caused by threshold voltage variations of the diode connecting switch due to capacitive coupling between the gate node of the switch and the storage capacitor. Therefore, the circuit configuration employs a triple-capacitor structure to significantly improve compensation performance and reliability.

公开(公告)号：US11049454B1

公开(公告)日：2021-06-29

申请号：US16941892

申请日：2020-07-29

Applicant: Sharp Kabushiki Kaisha

Inventor： Tong Lu

IPC: G09G3/3233 ,  G09G3/3266 ,  G09G3/3291

Abstract: A pixel circuit for a display device provides enhanced performance by performing drain-side initialization and data programming with respect to the drive transistor. The pixel circuit is operable in an initialization phase, a combined threshold compensation and data programming phase, and an emission phase, the pixel circuit including a drive transistor configured to control an amount of current to a light-emitting device during the emission phase depending upon a voltage applied to a gate of the drive transistor, and the drive transistor having a first terminal and a second terminal with the first terminal being electrically connected during the emission phase to a first voltage supply line that supplies a driving voltage. The second terminal of the drive transistor is electrically connected to a data voltage supply line that supplies a data voltage during the initialization phase and the combined threshold compensation and data programming phase to compensate a threshold voltage of the drive transistor and to program the data voltage.

公开(公告)号：US10984712B2

公开(公告)日：2021-04-20

申请号：US16214437

申请日：2018-12-10

Applicant: Sharp Kabushiki Kaisha

Inventor： Michael James Brownlow ,  Tong Lu

IPC: G09G3/30 ,  G09G3/3233 ,  G09G3/3275 ,  G09G3/3266

Abstract: A display system includes a pixel circuit and an external compensation system that is operable with the pixel circuit to compensate for differences in a property of the drive transistor and/or light-emitting device. The pixel circuit includes a drive transistor configured to control an amount of current to a light-emitting device; a second transistor having a first terminal connected to the gate of the drive transistor and a second terminal connected to a data voltage input that is supplied by the external compensation system, and a gate of the second transistor is connected to a first control signal; a third transistor having a first terminal connected to a second terminal of the drive transistor and a second terminal connected to a second voltage supply input that is supplied from the external compensation system, wherein a current flow from the second voltage supply input is measured by the external compensation system, and wherein a gate of the third transistor is connected to a second control signal; and a fourth transistor having a first terminal connected to the second terminal of the drive transistor and a second terminal connected to a third voltage supply input, wherein a gate of the fourth transistor is connected to a third control signal. The external voltage compensation system is configured to adjust the data voltage input based on the measured current flow to compensate for a variation in a property of the drive transistor and/or the light-emitting device.

公开(公告)号：US11011113B1

公开(公告)日：2021-05-18

申请号：US16830876

申请日：2020-03-26

Applicant: Sharp Kabushiki Kaisha

Inventor： Tong Lu ,  Michael James Brownlow ,  Tim Michael Smeeton

IPC: G09G3/3258 ,  G09G3/3266 ,  G09G3/325 ,  G09G3/3283

Abstract: A pixel circuit compensates the threshold voltage variations of the drive transistor with an ultra-short one horizontal (1H) time, with additionally removing the possible memory effects associated with the light-emitting device and the drive transistor from the previous frame. An ultra-short 1H time (

公开(公告)号：US10885843B1

公开(公告)日：2021-01-05

申请号：US16740763

申请日：2020-01-13

Applicant: Sharp Kabushiki Kaisha

Inventor： Tong Lu ,  Michael James Brownlow ,  Tim Michael Smeeton

IPC: G09G3/325 ,  G09G3/3266 ,  G09G3/3275

Abstract: A pixel circuit for a display device operable in an initialization phase, a compensation phase, a data programming phase, and an emission phase, whereby the one horizontal time is minimized while maintaining accurate compensation of the threshold voltages of the drive transistors, and further accounting for any variations in the voltage supplies. The pixel circuit includes a first drive transistor configured to control an amount of current to a light-emitting device during an emission phase depending upon voltages applied to a gate and a first terminal of the first drive transistor; and a second drive transistor that is configured as a source follower, wherein a first terminal of the second drive transistor is connected to a first power supply line and a second terminal of the second drive transistor is connected to a first terminal of the first drive transistor. The first drive transistor is one of a p-type or n-type transistor and the second drive transistor is the other of a p-type or n-type transistor. A light-emitting device is electrically connected at a first terminal to a second terminal of the first drive transistor during the emission phase and at a second terminal to a second power supply line.

公开(公告)号：US10714008B1

公开(公告)日：2020-07-14

申请号：US16429408

申请日：2019-06-03

Applicant: Sharp Kabushiki Kaisha

Inventor： Tong Lu

IPC: G09G3/20 ,  G09G3/3233 ,  G09G3/3266 ,  G09G3/3291

Abstract: A pixel circuit for a display device employs a two-capacitor configuration, in which during the emission phase, the first and second plates of the capacitors respectively are electrically connected to each other to provide more stability to the gate voltage of the drive transistor. The pixel circuit also is operable in a combined threshold compensation and data programming phase to compensate for variations in the characteristics of the drive transistor and the light-emitting device. During a portion of the combined threshold compensation and data programming phase the drive transistor becomes diode-connected such that the gate and the second terminal of the drive transistor are electrically connected, wherein a threshold voltage of the drive transistor is compensated while the drive transistor is diode-connected. A first capacitor has a first plate that is connected to the gate of the drive transistor and a second plate that is connected to a node N1 at the light-emitting device, and a second capacitor has a first plate that is connected to the gate of drive transistor and the first plate of the first capacitor, and a second plate that is electrically connected to the node N1 during the emission phase.

公开(公告)号：US10706782B2

公开(公告)日：2020-07-07

申请号：US16171718

申请日：2018-10-26

Applicant: Sharp Kabushiki Kaisha

Inventor： Tong Lu ,  Michael James Brownlow

IPC: G09G3/3258 ,  H01L27/12 ,  G09G3/3233

Abstract: A pixel circuit includes a drive transistor that controls an amount of current to a light-emitting device, and a second transistor connected to the gate of the drive transistor and a second terminal of the drive transistor, such that when the second transistor is in an on state the drive transistor becomes diode-connected. A threshold voltage of the drive transistor is compensated during a compensation phase while the drive transistor is diode connected. The light-emitting device is connected between the drive transistor and at a second node to a first voltage input. The pixel circuit further includes a storage capacitor having a first plate connected to the gate of the drive transistor, and a programming capacitor having a first plate connected to a second plate of the storage capacitor, and a second plate of the programming capacitor is electrically connected to a data voltage input during a data programming phase. The second plate of the storage capacitor and the first plate of the programming capacitor are connectable to a reference voltage to perform the compensation phase independently of the programming phase, and the storage capacitor and the programming capacitor are series connected during the emission phase.