# US 12,002,412 B2 · Display device

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- Number: US 12,002,412 B2
- Document ID: US12002412B2
- Status: Granted
- Kind: B2
- Application number: 18/121,868
- Filed: 2023-03-15
- Published: 2023-07-13
- Granted: 2024-06-04
- Earliest claimed: 2020-10-05
- Assignees: Samsung Electronics Co., Ltd.; Research & Business Foundation Sungkyunkwan University
- Applicants: Samsung Electronics Co., Ltd.; Research & Business Foundation Sungkyunkwan University
- Inventors: Jinho Kim; Yong-Sang Kim; Donggun Oh; Jongsu Oh; Eun Kyo Jung
- Web page: https://patentgrep.com/patent/US12002412B2

## CPC

- G09G 3/32: semiconductive, e.g. using light-emitting diodes [LED]
- H02M 1/0009: {Devices or circuits for detecting current in a converter}
- G09G 3/2014: {by modulation of the duration of a single pulse during which the logic level remains constant}
- G09G 3/2081: {with combination of amplitude modulation and time modulation (space and time error diffusion G09G3/2066)}
- H02M 3/158: including plural semiconductor devices as final control devices for a single load
- G09G 2300/0426: Layout of electrodes and connections
- G09G 2300/0819: used for counteracting undesired variations, e.g. feedback or autozeroing
- G09G 2300/0852: being a dynamic memory with more than one capacitor
- G09G 2300/0861: with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
- G09G 2310/0259: with use of an analog or digital ramp generator in the column driver or in the pixel circuit
- G09G 2310/061: for resetting or blanking
- G09G 2310/066: Waveforms comprising a gently increasing or decreasing portion, e.g. ramp
- G09G 2310/08: Details of timing specific for flat panels, other than clock recovery
- G09G 2320/0233: Improving the luminance or brightness uniformity across the screen
- G09G 2320/0295: by monitoring each display pixel
- G09G 2320/064: by time modulation of the brightness of the illumination source
- G09G 2330/025: Reduction of instantaneous peaks of current
- G09G 2360/145: the light originating from the display screen
- G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00)
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)

## Abstract

A display device includes a display panel including a pixel array including a plurality of pixels and a plurality of sub-pixel circuits, each pixel of the plurality of pixels including a plurality of inorganic light emitting elements and a sub-pixel circuit of the plurality of sub-pixel circuits being provided for an inorganic light emitting element of the plurality of inorganic light emitting elements, a driver configured to set the image data voltage to sub-pixel circuits included in each of the plurality of row lines in an order of the row lines, a sensing unit configured to sense a current flowing in a driving transistor included in the sub-pixel circuit based on a specific voltage applied to the sub-pixel circuit, and output sensing data corresponding to the sensed current, and a correction unit configured to correct the image data voltage applied to the sub-pixel circuit based on the sensing data.

## Claims

### Claim 1

A display device comprising:
a display panel comprising a pixel array comprising a plurality of pixels and a plurality of sub-pixel circuits, wherein the plurality of pixels are arranged in a plurality of row lines, each pixel of the plurality of pixels comprises a plurality of inorganic light emitting elements, a sub-pixel circuit of the plurality of sub-pixel circuits is provided for each inorganic light emitting element of the plurality of inorganic light emitting elements and is configured to drive the inorganic light emitting element based on an image data voltage, and each sub-pixel circuit of the plurality of sub-pixel circuits comprises a driving transistor;
a driver configured to set the image data voltage to sub-pixel circuits in each row line of the plurality of row lines in an order of the row lines, and drive sub-pixel circuits in at least two continued row lines among the plurality of row lines so that inorganic light emitting elements in the at least two continued row lines emit light in the order of the row lines based on the set image data voltage;
a sensing unit configured to sense a current flowing in the driving transistor of each sub-pixel circuit of the plurality of sub-pixel circuits based on a specific voltage applied to the sub-pixel circuit of the plurality of sub-pixel circuits, and output sensing data corresponding to the sensed current; and
a correction unit configured to correct the image data voltage applied to the sub-pixel circuit of the plurality of sub-pixel circuits based on the sensing data,
wherein the driver is further configured to:
set the image data voltage to the sub-pixel circuits in each row line of the plurality of row lines once during a data setting section for each row line of the plurality of row lines, and
drive the sub-pixel circuits in each row line of the plurality of row lines so that inorganic light emitting elements in each row line of the plurality of row lines emit light based on the set image data voltage a number of times during a plurality of light emitting sections for each row line of the plurality of row lines.

### Claim 2 (depends on 1)

The display device of claim 1, wherein the driver is further configured to:
drive the sub-pixel circuits in each row line of the plurality of row lines so that the inorganic light emitting elements in the at least two continued row lines emit light based on the set image data voltage in the plurality of light emitting sections for each row line of the plurality of row lines.

### Claim 3 (depends on 2)

The display device of claim 2, wherein a first light emitting section among the plurality of light emitting sections is temporally continuous with the data setting section, and each of the plurality of light emitting sections has a preset time interval.

### Claim 4 (depends on 2)

The display device of claim 2, wherein the plurality of row lines are divided into a plurality of groups, each of the plurality of groups comprising a number of continued row lines,
wherein the driver is further configured to:
during a first image frame section, set a first image data voltage to the sub-pixel circuits in each row line of the plurality of row lines in the order of the row lines from a first row line to a last row line of the plurality of row lines, and
during the first image frame section, drive the display panel so that inorganic light emitting elements in one group among the plurality of groups emit light in the order of the row lines, and then inorganic light emitting elements in each of at least two continued groups among the plurality of groups emit light in the order of the row lines based on the set first image data voltage, and
wherein the at least two continued groups comprise the one group.

### Claim 5 (depends on 4)

The display device of claim 4, wherein the driver is further configured to:
during a second image frame section before the first image frame section, set a second image data voltage to the sub-pixel circuits in each row line of the plurality of row lines from the first row line to the last row line of the plurality of row lines in the order of the row lines, and
during the first image frame section, drive the display panel so that inorganic light emitting elements in each of remaining groups of the plurality of groups excluding at least one group driven based on the first image data voltage emit light in the order of the row lines based on the second image data voltage.

### Claim 6 (depends on 5)

The display device of claim 5, wherein the driver is further configured to:
during the first image frame section, drive the display panel so that inorganic light emitting elements in each row line of each of the plurality of groups emit light a plurality of times based on at least one of the first image data voltage or the second image data voltage in the plurality of light emitting sections for each row line of the plurality of row lines.

### Claim 7 (depends on 2)

The display device of claim 2, wherein the image data voltage comprises a constant current generator data voltage and a pulse width modulation (PWM) data voltage, and
wherein each of the plurality of sub-pixel circuits comprises:
a constant current generator circuit comprising a first driving transistor and configured to control a size of a driving current provided to the inorganic light emitting element based on the constant current generator data voltage; and
a PWM circuit comprising a second driving transistor and configured to control a driving time of the driving current based on the PWM data voltage.

### Claim 8 (depends on 7)

The display device of claim 7, wherein each of the plurality of sub-pixel circuits further comprises a first transistor,
wherein a gate terminal of the first transistor is connected with the second driving transistor, and a source terminal or a drain terminal of the first transistor is connected with the first driving transistor, and
wherein the constant current generator circuit is further configured to:
based on the first transistor being turned on, provide the driving current having a size corresponding to the constant current generator data voltage flowing through the first driving transistor to the inorganic light emitting element, and
wherein the PWM circuit is further configured to:
based on the PWM data voltage being set to a gate terminal of the second driving transistor, turn off the first transistor based on the second driving transistor being turned on as a voltage of the gate terminal of the second driving transistor changes according to a sweep voltage.

### Claim 9 (depends on 8)

The display device of claim 8, wherein the PWM circuit further comprises a reset unit configured to turn on the first transistor before a start of each light emitting section.

### Claim 10 (depends on 8)

The display device of claim 8, wherein the first driving transistor, the second driving transistor, and the first transistor are PMOSFETs,
wherein the gate terminal of the first transistor is connected to a drain terminal of the second driving transistor, and the source terminal of the first transistor is connected to a drain terminal of the first driving transistor, and
wherein an anode terminal of the inorganic light emitting element is connected to the drain terminal of the first transistor, and a cathode terminal of the first transistor is connected to a ground voltage terminal.

### Claim 11 (depends on 8)

The display device of claim 8, wherein the first driving transistor, the second driving transistor, and the first transistor are PMOSFETs,
wherein the gate terminal of the first transistor is connected to a drain terminal of the second driving transistor, and the source terminal of the first transistor is connected to a drain terminal of the first driving transistor,
wherein an anode terminal of the inorganic light emitting element is connected to a driving voltage terminal, and a cathode terminal of the inorganic light emitting element is connected to the source terminal of the first driving transistor, and
wherein each of the plurality of sub-pixel circuits further comprises:
a second transistor that is connected to the inorganic light emitting element in parallel, and is turned on during the data setting section and is turned off in each of the plurality of light emitting sections.

### Claim 12 (depends on 8)

The display device of claim 8, wherein the first driving transistor, the second driving transistor, and the first transistor are NMOSFETs,
wherein the gate terminal of the first transistor is connected to a source terminal of the second driving transistor, and the drain terminal of the first transistor is connected to a source terminal of the first driving transistor, and
wherein an anode terminal of the inorganic light emitting element is connected to a driving voltage terminal, and a cathode terminal of the inorganic light emitting element is connected to a drain terminal of the first driving transistor.

### Claim 13 (depends on 7)

The display device of claim 7, wherein the constant current generator data voltage and the pulse width modulation (PWM) data voltage are applied to the constant current generator circuit and the PWM circuit, respectively, through separate data lines.

### Claim 14 (depends on 7)

The display device of claim 7, wherein the specific voltage comprises a first specific voltage applied to the constant current generator circuit and a second specific voltage applied to the PWM circuit, and
wherein the sensing unit is further configured to:
sense a first current flowing in the first driving transistor based on the first specific voltage, and output first sensing data corresponding to the sensed first current, and
sense a second current flowing in the second driving transistor based on the second specific voltage, and output second sensing data corresponding to the sensed second current.

### Claim 15 (depends on 14)

The display device of claim 14, wherein each of the plurality of sub-pixel circuits further comprises:
a third transistor configured to transmit the first current to the sensing unit; and
a fourth transistor configured to transmit the second current to the sensing unit, and
wherein each of the plurality of sub-pixel circuits is configured to:
provide the first current to the sensing unit through the third transistor while the first specific voltage is applied to the constant current generator circuit, and provide the second current to the sensing unit through the fourth transistor while the second specific voltage is applied to the PWM circuit.

### Claim 16 (depends on 14)

The display device of claim 14, wherein the correction unit is further configured to:
correct the constant current generator data voltage based on the first sensing data, and correct the PWM data voltage based on the second sensing data.

### Claim 17 (depends on 16)

The display device of claim 16, wherein the correction unit is further configured to:
obtain a first compensation value for correcting the constant current generator data voltage and a second compensation value for correcting the PWM data voltage based on a look-up table including sensing data values, and
correct the constant current generator data voltage and the PWM data voltage based on the obtained first compensation value and the obtained second compensation value, respectively.

### Claim 18 (depends on 1)

The display device of claim 1, wherein the driver is further configured to drive the sub-pixel circuits in each row line of the plurality of row lines so that the inorganic light emitting elements in each row line of the plurality of row lines emit light based on the set image data voltage during each of the plurality of light emitting sections.

### Claim 19 (depends on 1)

The display device of claim 1, wherein the driver is further configured to:
drive sub-pixel circuits in a first row line of the plurality of row lines so that inorganic light emitting elements in the first row line emit light during a first light emitting section of the first row line among the plurality of light emitting sections,
drive sub-pixel circuits in a second row line of the plurality of row lines so that inorganic light emitting elements in the second row line emit light during a first light emitting section of the second row line among the plurality of light emitting sections after the first light emitting section of the first row line starts and before the first light emitting section of the first row line is completed, and
drive sub-pixel circuits in a third row line of the plurality of row lines so that inorganic light emitting elements in the third row line emit light during a first light emitting section of the third row line among the plurality of light emitting sections after the first light emitting section of the second row line starts and before the first light emitting section of the second row line are completed.