CN110910806A

CN110910806A - Display device

Info

Publication number: CN110910806A
Application number: CN201910319645.4A
Authority: CN
Inventors: 吴宏蛟; 陈厚典; 黄冠宪
Original assignee: Innolux Corp
Current assignee: Innolux Corp
Priority date: 2018-09-17
Filing date: 2019-04-19
Publication date: 2020-03-24
Anticipated expiration: 2039-04-19
Also published as: KR102664524B1; CN110910806B; KR20200032641A

Abstract

A display device comprises a pixel array, a power line, a ground line, at least one power detection line, at least one ground detection line and a power supply circuit. The power supply circuit provides a power supply voltage through a power line and a ground voltage through a ground line to the pixel array, receives at least one detection power supply voltage from the pixel array through at least one power detection line and at least one detection ground voltage through at least one ground detection line, and adjusts the power supply voltage and/or the ground voltage according to the at least one detection power supply voltage and the at least one detection ground voltage.

Description

Display device

Technical Field

The present invention relates to a display device, and more particularly, to a display device capable of monitoring a voltage of a pixel array.

Background

Display devices, such as smart phones, tablet computers, notebook computers, monitors, and televisions, have become an indispensable necessity in modern society. With the explosion of display devices, consumers have a high expectation on the quality, functionality, or price of these products.

However, the development of stable display devices is still one of the subjects of research in the industry.

Disclosure of Invention

Drawings

Fig. 1 is a system diagram of a display device of an embodiment of the present invention.

Fig. 2 is a block diagram of a power supply circuit within the display device of fig. 1.

Fig. 3 is a circuit diagram of a power supply circuit within the display device of fig. 1.

Fig. 4 is a schematic view of a portion of a bonding pad of the pixel array in the display device of fig. 1.

Description of reference numerals: 1-a display device; 10-a pixel array; 12-a power line; 14-a ground line; 16-a power detection line; 17-a ground detection line; 18-a power supply circuit; 180-a control circuit; 182-a voltage compensation circuit; 1820-voltage averaging circuit; 1822-voltage difference circuit; 184-overvoltage protection circuit; 1840-microcontroller; cst-capacitance; a D-light emitting diode; m1, M2-transistors; an OP-operational amplifier; p (M, N) -pixels; r1 to R18-resistors; an SW-switch; VDD-supply voltage; VDD' -the drive supply voltage; VDDdet-detecting the supply voltage; VDDdet (0:5) -detecting the supply voltage; VDD (M, N) -pixel supply voltage; VSS-ground voltage; VSS' -drive ground voltage; VSSdet-detecting a ground voltage; VSSdet (0:5) -detecting the ground voltage; VSS (M, N) -pixel ground voltage.

Detailed Description

Fig. 1 is a system diagram of a display device 1 of an embodiment of the present invention. The display device 1 may include a flexible display device (flexible display device), a touch display device (touch display device), a curved display device (curved display device), a tiled display device (tiled display device), other suitable display devices, or a combination thereof, but the invention is not limited thereto. The display device 1 may include a pixel array 10, a power line 12, a ground line 14, at least one power detection line 16, at least one ground detection line 17, and a power supply circuit 18. The power supply circuit 18 may provide a power supply voltage VDD through the power line 12 and a ground voltage VSS through the ground line 14 to the pixel array 10. In one embodiment, the ground voltage VSS according to the present invention may refer to ground, a low level voltage, or a reference voltage, but is not limited thereto. In another embodiment, the supply voltage VDD and the ground voltage VSS may be controlled by an integrated circuit (integrated circuit) in the supply circuit 18, and the supply voltage VDD and the ground voltage VSS may be obtained by measuring pins (pins) of the integrated circuit, but is not limited thereto. The supply voltage VDD and/or the ground voltage VSS may be dropped during transmission. The power supply circuit 18 may receive at least one detection power supply voltage VDDdet from the pixel array 10 through at least one power detection line 16 and/or at least one detection ground voltage VSSdet through at least one ground detection line 17. In one embodiment, the power supply circuit 18 adjusts the supply voltage VDD and/or the ground voltage VSS according to the at least one detected supply voltage VDDdet and the at least one detected ground voltage VSSdet to compensate for the voltage drop. At least one detection supply voltage VDDdet and/or at least one detection ground voltage VSSdet may be obtained from selected locations of the pixel array 10, such as at least one pixel may be selected for detection. For example, the power detection line 16 and/or the ground detection line 17 may be additionally wired from the selected pixel to the power supply circuit 18. The power detection line 16 and/or the ground detection line 17 may also be wired from the peripheral region of the pixel array 10 to the power supply circuit 18. The detection supply voltage VDDdet and/or the detection ground voltage VSSdet may be measured from the above-mentioned locations (e.g., the periphery or selected pixels), but is not limited thereto. In some embodiments, the power supply circuit 18 may receive only one of the detection supply voltage VDDdet and the detection ground voltage VSSdet. For example, considering that the number of lines may be too large, the display apparatus 1 may include only the power detection line 16 without the ground detection line 17, and the detection ground voltage VSSdet may be replaced by a default value, but the invention is not limited thereto. The pixel array 10 transmits the power supply voltage VDD and the ground voltage VSS to the pixels P of the pixel array 10 as the power supply voltage of the pixels and the ground voltage of the pixels, respectively. The at least one power detection line 16 and the at least one ground detection line 17 may include a plurality of power detection lines 16 and a plurality of ground detection lines 17, or only include a single power detection line 16 and a single ground detection line 17. The at least one detection supply voltage VDDdet and the at least one detection ground voltage VSSdet may include a plurality of detection supply voltages VDDdet and a plurality of detection ground voltages VSSdet, or only include a single detection supply voltage VDDdet and a single detection ground voltage VSSdet.

In one embodiment, the pixel array 10 may include a plurality of pixels P, and a particular pixel P in the pixel array 10 may be represented by P (M, N), where M is a row index, N is a column index, and M and N are positive integers. Each pixel P (M, N) may include a transistor M1, M2, a capacitor Cst, and a light emitting element D, and may be coupled to a power supply voltage VDD (M, N) and a ground voltage VSS (M, N). Due to the line impedance, the pixel supply voltage VDD (M, N) and the pixel ground voltage VSS (M, N) may be different for different pixels P (M, N). The circuit designer can obtain the corresponding pixel power supply voltage VDD (M, N) and ground voltage VSS (M, N) from the positions of the pixels P (M, N) of the pixel array 10 as the plurality of detection power supply voltages VDDdet (M, N) and the plurality of detection ground voltages VSSdet (M, N) according to the size of the pixel array 10, for example, obtain the corresponding power supply voltages VDD (1,1), VDD (1, N), VDD (3,1), VDD (3, N), VDD (M,1), VDD (M, N) from the positions of the pixels P (1,1), P (1, N), P (3,1), P (3, N), VDD (M,1), VDD (M, N) as the plurality of detection power supply voltages VDDdet (1,1), VDDdet (3,1), VDD det (3, N), VDDdet (M,1), VDDdet (M, N); and obtaining corresponding grounding voltages VSS (1,1), VSS (1, N), VSS (3,1), VSS (3, N), VSS (M,1), VSS (M, N) as a plurality of detection grounding voltages VSSdet (1,1), VSSdet (1, N), VSSdet (3,1), VSSdet (3, N), VSSdet (M,1), VSSdet (M, N). The detection supply voltages VDDdet and the detection ground voltages VSSdet can be obtained from any different positions of the pixel array 10. For example, when the display device 1 is applied to a tiled display (tiled display device), the sensing supply voltages VDDdet and the sensing ground voltages VSSdet can be obtained from the pixels P at the edge or corner of the pixel array 10, so that the brightness of the pixels P at the edge of the pixel array 10 is substantially the same.

In one embodiment, the power supply circuit 18 can adjust the power supply voltage VDD and/or the ground voltage VSS by at least one detected power supply voltage VDDdet and at least one detected ground voltage VSSdet to control the difference between the power supply voltage VDD (M, N) and the ground voltage VSS (M, N) within an allowable value of a target value, for example, between a target value of 90% and a target value of 100%.

The pixel array 10 may include an active matrix pixel array (active matrix pixel array), a passive matrix pixel array (passive matrix pixel array), or a combination thereof. In one embodiment, the pixel array 10 may comprise a liquid crystal pixel array. In some embodiments, the light emitting element D may include a Light Emitting Diode (LED), an Organic Light Emitting Diode (OLED), a Quantum Dot (Quantum Dot), a submillimeter light emitting diode (Mini LED), a Micro LED (Micro LED), a Quantum Dot light emitting diode (QD-LED, QLED), a phosphor material (phosphors), or a fluorescent material (phosphor), but the invention is not limited thereto. The display device 1 is not limited to use only a single type of pixel P, and different types of pixels P (e.g. including different light emitting elements) can also be used, and the above examples are not intended to be limiting. In some embodiments, the at least one detection supply voltage VDDdet and the at least one detection ground voltage VSSdet may be obtained from the same or different positions of the pixels P of the pixel array 10.

Fig. 2 is a block diagram of power supply circuitry 18 within display device 1 according to some embodiments of the present disclosure. In some embodiments, the power supply circuit 18 may include a control circuit 180, a voltage compensation circuit 182, and an overvoltage protection circuit 184. The voltage compensation circuit 182 may include a voltage averaging circuit 1820 and a voltage difference circuit 1822. The power supply circuit 18 may receive at least one detection power supply voltage VDDdet and/or at least one detection ground voltage VSSdet from the pixel array 10 through at least one power detection line 16 and/or at least one ground detection line 17, respectively. The voltage averaging circuit 1820 may be coupled to the pixel array 10 via at least one power detection line 16 and/or at least one ground detection line 17. The voltage difference circuit 1822 may be coupled to the voltage averaging circuit 1820. The control circuit 180 may be coupled to the voltage difference circuit 1822 and the over-voltage protection circuit 184. The control circuit 180 may also be coupled to the pixel array 10 via the power line 12 and the ground line 14. The overvoltage protection circuit 184 may be coupled to the control circuit 180, the voltage compensation circuit 182, the power line 12 and the ground line 14.

In one embodiment, the voltage compensation circuit 182 and the control circuit 180 may compensate for the voltage drop of the supply voltage VDD and/or the ground voltage VSS according to the at least one detected supply voltage VDDdet and/or the at least one detected ground voltage VSSdet. In particular, the voltage averaging circuit 1820 may generate the supply voltage average according to the detected supply voltages VDDdet and/or generate the ground voltage average according to the detected ground voltages VSSdet. The voltage difference circuit 1822 may generate a difference according to the supply voltage average and the ground voltage average, and the control circuit 180 may update the supply voltage VDD and/or the ground voltage VSS according to the difference. In some embodiments, the control circuit 180 may raise the supply voltage VDD and/or lower the ground voltage VSS when the difference is less than a predetermined value. In other embodiments, the control circuit 180 may lower the supply voltage VDD and/or raise the ground voltage VSS when the difference is greater than a predetermined value.

When the power detection line 16 and/or the ground detection line 17 are disconnected to make the control circuit 180 continuously raise the power supply voltage VDD and/or lower the ground voltage VSS, the over-voltage protection circuit 184 can protect the circuits in the pixel array 10, thereby reducing the damage caused by the excessively high power supply voltage VDD and/or the excessively low ground voltage VSS. In some embodiments, when the supply voltage VDD is higher than the predetermined high voltage, the over-voltage protection circuit 184 may output an over-voltage signal to the control circuit 180 to update the supply voltage VDD to the predetermined high voltage, while the control circuit 180 maintains the voltage difference between the supply voltage VDD and the ground voltage VSS within a tolerance value of a target value, for example, between 90% of the target voltage and 100% of the target voltage. In other embodiments, when the ground voltage VSS is lower than the predetermined low voltage, the over-voltage protection circuit 184 may output an over-voltage signal to the control circuit 180 to update the ground voltage VSS to the predetermined low voltage, and the control circuit 180 may maintain the voltage difference between the power supply voltage VDD and the ground voltage VSS within the tolerance of the target value. In other embodiments, the over-voltage protection circuit 184 may output an over-voltage signal to the control circuit 180 to refresh the supply voltage VDD to a predetermined high voltage when the supply voltage VDD is higher than the predetermined high voltage, while the control circuit 180 maintains the voltage difference between the supply voltage VDD and the ground voltage VSS within the tolerance of the target voltage Vtarget, and the over-voltage protection circuit 184 may output an over-voltage signal to the control circuit 180 to refresh the ground voltage VSS to a predetermined low voltage when the ground voltage VSS is lower than the predetermined low voltage, while the control circuit 180 maintains the voltage difference between the supply voltage VDD and the ground voltage VSS within the tolerance of the target voltage Vtarget. In other embodiments, when the supply voltage VDD is higher than the predetermined high voltage or the ground voltage VSS is lower than the predetermined low voltage, the over-voltage protection circuit 184 can switch off the connection between the voltage compensation circuit 182 and the control circuit 180, so that the control circuit 180 can no longer update the supply voltage VDD and/or the ground voltage VSS according to the detected supply voltage VDDdet and/or the detected ground voltage VSSdet.

In some embodiments, the power supply circuit 18 is not limited to fig. 2, and the power supply voltage VDD and/or the ground voltage VSS may be updated according to the single detection power supply voltage VDDdet and/or the single detection ground voltage VSSdet. The power supply circuit 18 may include a voltage difference circuit 1822, a control circuit 180, and an overvoltage protection circuit 184. The voltage difference circuit 1822 may be coupled to the pixel array 10. The control circuit 180 may be coupled to the voltage difference circuit 1822, and the overvoltage protection circuit 184 may be coupled to the control circuit 180, the power line 12, and the ground line 14. In one embodiment, the voltage difference circuit 1822 generates a difference according to the single detection supply voltage VDDdet and/or the single detection ground voltage VSSdet, and the control circuit 180 updates the supply voltage VDD and/or the ground voltage VSS according to the difference. When the supply voltage is higher than the predetermined high voltage, the over-voltage protection circuit 184 may output an over-voltage signal to the control circuit 180 to update the supply voltage VDD to the predetermined high voltage, but not limited thereto.

Fig. 3 is a circuit diagram of power supply circuitry 18 within the display device of fig. 1 according to some embodiments of the present invention. In one embodiment, the power supply circuit 18 shown in fig. 3 may be different from the embodiment of fig. 2. The power supply circuit 18 may include a control circuit 180, a voltage compensation circuit 182, and an overvoltage protection circuit 184. The voltage compensation circuit 182 may receive, for example, 6 detection supply voltages VDDdet (0:5) and/or 6 detection ground voltages VSSdet (0:5), but the invention is not limited thereto. The voltage compensation circuit 182 is electrically connected to the control circuit 180, but when the overvoltage is detected by the voltage protection circuit 184, the electrical connection between the voltage compensation circuit 182 and the control circuit 180 is cut off. The overvoltage protection circuit 184 may be coupled to the power line 12 and coupled between the control circuit 180 and the voltage compensation circuit 182. The voltage compensation circuit 182 may include, for example, a weighted sum (weighted sum) and/or differential (differential) amplifier. In one embodiment, the compensation circuit 182 may include resistors (e.g., resistors R1-R16) and an operational amplifier OP. The inverting input terminal of the operational amplifier OP may be coupled to a sense ground voltage (e.g., sense ground voltage VSSdet (0: 5)). The non-inverting input of the operational amplifier OP may be coupled to the sense supply voltage (e.g., the sense supply voltage VDDdet (0: 5)). For example, the operational amplifier OP and the resistors R1-R6 and R13, R14 may generate the ground voltage average of the detection ground voltage VSSdet (0: 5). The operational amplifier OP and the resistors R7-R12 and R15, R16 generate a supply voltage average value of the detection supply voltage VDDdet (0: 5). The operational amplifier OP may generate a difference between the average value of the supply voltage and the average value of the ground voltage. The difference is sent to the control circuit 180 via the over-voltage protection circuit 184 to update the supply voltage VDD according to the difference. The overvoltage protection circuit 184 may include a switch SW, a Microcontroller (MCU) 1840, and a voltage divider. The voltage divider may include resistors R17 and R18. The voltage divider may detect the supply voltage VDD and transmit the detection result to the microcontroller 1840. When the detected result is higher than the predetermined high voltage, the microcontroller 1840 may output an over-voltage signal to the control circuit 180 to update the supply voltage VDD to the predetermined high voltage, and open the switch SW to disconnect the connection between the voltage compensation circuit 182 and the control circuit 180. In some embodiments, the control circuit 180 may include various functions or nodes, such as, but not limited to, a switch SW, a ground GND, a power good PGOOD, a voltage feedback FB, an enable EN, a circuit supply voltage VCC, a power input voltage VIN, and/or a bootstrap boost (boost) device BOOT. For example, the function of power stabilization PGOOD may include providing a power stabilization signal to enable circuitry within the power supply to begin operating to power the device when the output voltage is stable and normal to meet the power requirements of the circuitry. The voltage feedback FB can provide compensation voltage to make the output voltage more stable. The bootstrap boost element BOOT may boost the voltage.

Fig. 4 is a schematic illustration of a portion of a bond pad of pixel array 10 within display device 1 of fig. 1 according to some embodiments of the present invention. The peripheral region (e.g., the bond pad) of the pixel array 10 may include a conductive pad Rm1, a conductive pad Gm1, a conductive pad Bm1, a conductive pad Rm2, a conductive pad Gm2, and a conductive pad Bm 2. In one embodiment, each pixel P (M, N) in the pixel array 10 may include a plurality of sub-pixels, such as 3, or 4, but the invention is not limited thereto. The sub-pixels may include red, green, and blue sub-pixels, but are not limited thereto. Each sub-pixel may have an independent power supply voltage VDD (M, N), and the red, green, and blue sub-pixels may share the same ground voltage VSS (M, N). For example, the sub-pixel supply voltages VDD (M, N) of 2 pixels at a selected position in the pixel array 10 are respectively coupled to the conducting pad Rm1, the conducting pad Gm1, the conducting pad Bm1, the conducting pad Rm2, the conducting pad Gm2, and the conducting pad Bm2 through conducting wires, and then transmitted to the power supply circuit 18 through the plurality of power detection lines 16 and the plurality of ground detection lines 17 (e.g., at least a portion of conducting wires on a Flexible Printed Circuit (FPC)) to adjust the supply voltage VDD and/or the ground voltage VSS.

The display device 1 of fig. 1 to 4 can be used to detect the internal voltage of the pixel array 10 to provide the pixel array 10 with a sufficient supply voltage VDD.

The above description is only an example of the present invention, and is not intended to limit the present invention, and it is obvious to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A display device, comprising:

an array of pixels;

a power line;

a ground line;

at least one power detection line;

at least one grounding detection line; and

the power supply circuit is used for providing power supply voltage through the power line and grounding voltage through the grounding line to the pixel array, receiving at least one detection power supply voltage from the pixel array through the at least one power detection line and at least one detection grounding voltage through the at least one grounding detection line, and adjusting the power supply voltage and/or the grounding voltage according to the at least one detection power supply voltage and the at least one detection grounding voltage.

2. The display device of claim 1, wherein the at least one power detection line and the at least one ground detection line comprise a plurality of power detection lines and a plurality of ground detection lines, respectively, the at least one sense supply voltage and the at least one sense ground voltage comprise a plurality of sense supply voltages and a plurality of sense ground voltages, respectively, and the plurality of sense supply voltages are derived from a plurality of distinct locations of the pixel array, the plurality of ground voltages being derived from the plurality of distinct locations of the pixel array.

3. The display device of claim 2, wherein the power supply circuit comprises:

a voltage averaging circuit, coupled to the pixel array, for generating a supply voltage average according to the plurality of sensing supply voltages and generating a ground voltage average according to the plurality of sensing ground voltages;

a voltage difference circuit coupled to the voltage averaging circuit for generating a difference according to the supply voltage average value and the ground voltage average value; and

the control circuit is coupled to the voltage difference circuit and used for updating the power supply voltage and/or the grounding voltage according to the difference.

4. The display device of claim 3, wherein the power supply circuit further comprises:

the overvoltage protection circuit is coupled to the control circuit and the power line and used for outputting an overvoltage signal to the control circuit to update the power supply voltage to the preset high voltage when the power supply voltage is higher than the preset high voltage.

5. The display device of claim 3, wherein the power supply circuit further comprises:

the overvoltage protection circuit is coupled to the control circuit and the ground line, and is used for outputting an overvoltage signal to the control circuit to update the ground voltage to a predetermined low voltage when the ground voltage is lower than the predetermined low voltage.

6. The display device according to claim 3, wherein the control circuit raises the supply voltage and/or lowers the ground voltage when the difference is smaller than a predetermined value.

7. The display device of claim 3, wherein the control circuit lowers the supply voltage and/or raises the ground voltage when the difference is greater than a predetermined value.

8. The display device of claim 1, wherein:

the at least one power detection line and the at least one grounding detection line are respectively a single power detection line and a single grounding detection line;

the at least one detection supply voltage and the at least one detection ground voltage are respectively a single detection supply voltage and a single detection ground voltage obtained from the same position of the pixel array; and

the power supply circuit includes:

a voltage difference circuit coupled to the pixel array for generating a difference according to the single detection supply voltage and the single detection ground voltage; and

9. The display device of claim 8, wherein the power supply circuit further comprises:

10. The display device of claim 8, wherein the power supply circuit further comprises: