CN114241991B - Light-emitting unit control circuit, method, array substrate and display panel - Google Patents
Light-emitting unit control circuit, method, array substrate and display panel Download PDFInfo
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- CN114241991B CN114241991B CN202111650710.5A CN202111650710A CN114241991B CN 114241991 B CN114241991 B CN 114241991B CN 202111650710 A CN202111650710 A CN 202111650710A CN 114241991 B CN114241991 B CN 114241991B
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- 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]
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- 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
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- 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
- G09G2320/0233—Improving the luminance or brightness uniformity across the screen
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- 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
- G09G2320/0257—Reduction of after-image effects
Abstract
The invention provides a light-emitting unit control circuit, a light-emitting unit control method, an array substrate and a display panel, wherein the light-emitting unit control circuit comprises an acquisition circuit and a drive circuit, the acquisition circuit is connected with the drive circuit and a front-end control chip, the front-end control chip is connected with a light-emitting unit through the drive circuit, a switch circuit is arranged between the front-end control chip and the light-emitting unit, and the switch circuit is connected with the drive circuit in series; in the invention, the drive circuit between the drive circuit and the light-emitting unit is controlled to be switched on or switched off through the PWM signal and the current drive current in the drive circuit is increased to the preset drive current, so that the charge quantity input into the light-emitting unit in unit time is accurately acquired in a low-gray-scale state, and the accurate compensation of the light-emitting unit is realized.
Description
Technical Field
The invention relates to the technical field of display, in particular to a light-emitting unit control circuit, a light-emitting unit control method, an array substrate and a display panel.
Background
Organic light emitting display diodes have been increasingly used in high performance displays as a current type light emitting device. Brightness uniformity and image retention are two major problems facing it, and to solve these two problems, besides process improvement, related compensation techniques are also needed. The electrical compensation is a mode of external compensation, and the electrical parameter characteristics of the thin film transistor in the pixel are read to an external induction circuit, and a driving voltage value needing to be compensated is calculated and fed back to a chip of the driving panel, so that the compensation is realized.
When the organic light emitting display diode is in low gray scale brightness, the current of the pixel circuit passing through the organic light emitting display diode and the thin film transistor is very weak, namely the charge amount in unit time is very small, and the front end control chip has certain precision requirement on the detected current, so that the external compensation capability is not accurate enough when the gray scale is low.
The above is only for the purpose of assisting understanding of the technical solution of the present invention, and does not represent an admission that the above is the prior art.
Disclosure of Invention
The invention mainly aims to provide a light-emitting unit control circuit, a light-emitting unit control method, an array substrate and a display panel, and solves the technical problem that the external compensation capability is not accurate enough in low gray scale.
In order to solve the technical problem, the invention provides a light-emitting unit control circuit, which comprises an acquisition circuit and a drive circuit, wherein the acquisition circuit is connected with the drive circuit and a front-end control chip, the front-end control chip is connected with a light-emitting unit through the drive circuit, a switch circuit is arranged between the front-end control chip and the light-emitting unit, and the switch circuit is connected with the drive circuit in series;
the switch circuit is used for switching on or off a driving loop between the driving circuit and the light-emitting unit according to a PWM signal output by a front-end control chip when the acquisition circuit acquires the charge quantity input to the light-emitting unit in unit time;
the driving circuit is used for increasing the current driving current in the driving circuit to a preset driving current when the driving circuit is conducted, and the current value of the preset driving current is inversely related to the duty ratio of the PWM signal.
Optionally, the switching circuit is disposed between the driving circuit and the light emitting unit.
Optionally, the switching circuit comprises: a first thin film transistor;
the grid electrode of the first thin film transistor is connected with the PWM signal output end of the front-end control chip, the source electrode of the first thin film transistor is connected with the output end of the driving circuit and the input end of the acquisition circuit, and the drain electrode of the first thin film transistor is connected with the input end of the light-emitting unit.
Optionally, the light emitting unit control circuit further comprises: a second thin film transistor;
the grid electrode of the second thin film transistor is connected with the front-end control chip, the source electrode of the second thin film transistor is connected with a reference power supply, and the source electrode of the second thin film transistor is connected with the driving circuit.
In order to achieve the above object, the present invention further provides a light emitting unit control method based on the light emitting unit control circuit, the light emitting unit control method comprising:
when the acquisition circuit acquires the charge quantity input into the light-emitting unit in unit time, the switch circuit switches on or off a driving loop between the driving circuit and the light-emitting unit according to a PWM (pulse width modulation) signal output by a front-end control chip;
when the driving circuit is conducted, the driving circuit raises the current driving current in the driving circuit to a preset driving current to drive the light-emitting unit, and the current value of the preset driving current is inversely related to the duty ratio of the PWM signal.
Optionally, before the step of turning on or off the driving circuit between the driving circuit and the light emitting unit according to the PWM signal output by the front end control chip, the method further includes:
the acquisition circuit acquires the current driving charge quantity generated by the current driving current for driving the light-emitting unit in unit time;
the front-end control chip determines the current gray-scale value of the light-emitting unit according to the current driving charge quantity;
and the front-end control chip outputs a PWM signal when the current gray-scale value is lower than a preset gray-scale value.
Optionally, after the step of raising the current driving current to the preset driving current to drive the light emitting unit when the driving circuit is turned on, the method further includes:
and the acquisition circuit acquires the preset driving charge quantity generated by the preset driving current in unit time when the driving circuit is disconnected.
Optionally, the light emitting unit control method includes:
the driving circuit drives the light-emitting unit according to the current driving current when the acquisition circuit acquires the charge quantity input to the light-emitting unit in unit time;
and the switch circuit disconnects a driving loop between the driving circuit and the light-emitting unit according to a cut-off signal output by the front-end control chip.
In addition, to achieve the above object, the present invention also provides an array substrate, including: a light emitting unit and the light emitting unit control circuit.
In addition, in order to achieve the above object, the present invention further provides a display panel, where the display panel includes a light emitting layer and the array substrate, and the light emitting layer is disposed on the array substrate.
The invention provides a light-emitting unit control circuit, a light-emitting unit control method, an array substrate and a display panel, wherein the light-emitting unit control circuit comprises an acquisition circuit and a drive circuit, the acquisition circuit is connected with the drive circuit and a front-end control chip, the front-end control chip is connected with a light-emitting unit through the drive circuit, a switch circuit is arranged between the front-end control chip and the light-emitting unit, and the switch circuit is connected with the drive circuit in series; when the acquisition circuit acquires the charge quantity input into the light-emitting unit in unit time, the switch circuit switches on or off a driving loop between the driving circuit and the light-emitting unit according to a PWM (pulse width modulation) signal output by a front-end control chip; when the driving circuit is conducted, the current driving current in the driving circuit is increased to a preset driving current, and the current value of the preset driving current is inversely related to the duty ratio of the PWM signal. In the invention, the drive circuit between the drive circuit and the light-emitting unit is controlled to be switched on or switched off through the PWM signal and the current drive current in the drive circuit is increased to the preset drive current, so that the charge quantity input into the light-emitting unit in unit time is accurately acquired in a low-gray-scale state, and the accurate compensation of the light-emitting unit is realized.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only the first embodiment, the second embodiment, the third embodiment of the array substrate, the embodiment of the display panel, and the corresponding drawings of the embodiment of the display of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in these drawings without any creative effort.
FIG. 1 is a first circuit structure diagram of a light-emitting unit control circuit according to a first embodiment of the present invention;
FIG. 2 is a second circuit structure diagram of a light-emitting unit control circuit according to a first embodiment of the present invention;
FIG. 3 is a schematic diagram of driving signals of the light emitting unit in different gray scale states;
FIG. 4 is a circuit diagram of a second embodiment of a light-emitting unit control circuit according to the present invention;
FIG. 5 is a timing diagram of the control logic of the front end control chip of the light emitting unit;
FIG. 6 is a circuit diagram of a third embodiment of a light-emitting unit control circuit according to the present invention;
FIG. 7 is a flowchart illustrating a method for controlling a light-emitting unit according to a first embodiment of the present invention;
FIG. 8 is a flowchart illustrating a second method for controlling a light-emitting unit according to an embodiment of the present invention;
FIG. 9 is a flowchart illustrating a third method for controlling a light-emitting unit according to an embodiment of the present invention;
fig. 10 is a schematic structural diagram of a display panel according to an embodiment of the present application.
The reference numbers illustrate:
| reference numerals | Name (R) | Reference numerals | Name (R) | |
| Vdata | Scanning voltage | Vref | Reference power supply | |
| Scan1 | Pre-charge signal | PVEE | Ground connection | |
| Scan2 | Drive signal | T1～T5 | First to fifth thin film transistors | |
| | Driving voltage | 10 | Acquisition circuit | |
| D1 | A first organic |
20 | Driving circuit | |
| C1～C2 | First to |
30 | Switching circuit | |
| PWM | PWM signal | | Acquisition signal | |
| 40 | |
50 | Luminescent layer |
The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention.
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.
Referring to fig. 1 and 2, fig. 1 is a first circuit structure diagram of a light emitting unit control circuit according to a first embodiment of the light emitting unit control circuit of the present invention; fig. 2 is a second circuit structure diagram of a light emitting unit control circuit according to a first embodiment of the present invention. Referring to fig. 1 and 2, a first embodiment of a light emitting unit control circuit according to the present invention is provided.
In the first embodiment of the light emitting unit control circuit, the light emitting unit control circuit includes an acquisition circuit 10 and a driving circuit 20, the acquisition circuit 10 is connected to the driving circuit 20 and a front end control chip, the front end control chip is connected to the light emitting unit through the driving circuit 20, a switch circuit 30 is disposed between the front end control chip and the light emitting unit, and the switch circuit 30 is connected in series to the driving circuit 20.
It should be understood that, when compensating the brightness of the organic light emitting diode, it is necessary to collect the driving current of the organic light emitting diode to determine the relationship between the driving current of the organic light emitting diode and the brightness of the organic light emitting diode in the current state, and then compensate the brightness of the organic light emitting diode by adjusting the input driving current or driving voltage. The organic light emitting diode is in a high gray scale state, the driving current for driving is large, a specific current value can be accurately acquired in the acquisition process, and in a low gray scale state, the driving current for driving is very small, so that the acquired driving current is inaccurate.
It is understood that, in collecting the driving current, the amount of charge input to the light emitting unit is actually collected. The formula Q = C I t for calculating the charge amount, where Q is the charge amount, C is the capacitance value of the collecting capacitor, I is the driving current, and t is the time when the driving current is input. According to the calculation formula of the charge quantity, the larger charge quantity collected in a certain collection time can be obtained by adjusting the driving current.
The switch circuit 30 is a circuit for controlling whether or not a drive circuit between the drive power supply PVDD and the light emitting unit is on. The switch circuit 30 may be a current composed of a power transistor and other related components, and referring to fig. 1, the switch circuit 30 is embodied by a first thin film transistor T1 in fig. 1, and the specific structure of the switch circuit 30 is not limited in this embodiment. The front-end control chip is used for controlling the driving and compensation of the light-emitting unit, and can control the connection or disconnection of each loop by inputting related driving signals to the switching elements in each loop. The front-end control chip can adjust the opening degree of the third thin film transistor T3 and the fourth thin film transistor T4 by adjusting the voltage value of the driving signal, so as to adjust the driving current in the driving circuit, which is not shown in the figure. The light emitting unit may be a pixel, and the light emitting unit may be composed of a first organic light emitting diode D1, a second capacitor C2, and other related components, and the connection of other components is not specifically limited herein.
In a specific implementation, when the charge amount is collected, the front end control chip firstly outputs the driving signal Scan1 to the gate of the third thin film transistor T3 to control the third thin film transistor T3 to be turned on, so that the scanning voltage Vdata is input to the gate of the fourth thin film transistor T4 to control the fourth thin film transistor T4 to be turned on. Then, the front-end control chip can output a PWM signal to the switch circuit 30, and the switch circuit 30 switches on the driving circuit between the driving circuit and the light emitting unit within the effective duty cycle time of the PWM signal according to the PWM signal output by the front-end control chip; when the driving circuit 20 is turned on, the current driving current provided by the driving voltage is increased to the preset driving current to drive the light emitting unit, and finally the front end control chip outputs the collecting signal Sensor to the gate of the fifth thin film transistor T5 to turn on the fifth thin film transistor T5, so as to collect the amount of electric charge input to the light emitting unit in unit time. Here, the driving time within a single frame is controlled by the PWM signal while increasing the current value in the driving circuit 20, thereby ensuring that the luminance of the light emitting unit remains unchanged.
The preset driving current is a current with a preset current value larger than that of the normal driving current. The current value of the preset driving current is greater than that of a normal driving current of the light emitting unit driven in a normal state. When the duty ratio of the PWM signal is 100%, the driving current input to the light emitting unit is a normal driving current. The current value of the preset driving current is inversely related to the duty ratio of the PWM signal. Referring to fig. 3, when the light emitting unit is driven at a rated current, the larger the duty ratio of the PWM signal, the larger the luminance of the light emitting unit, and the larger the gray-scale value of the pixel. In this embodiment, in order to ensure that the total charge amount input to the light emitting unit per unit time is not changed, the larger the current value of the preset driving current is, the smaller the duty ratio of the corresponding PWM signal is, thereby maintaining the gray-scale value of the pixel.
In the first embodiment of the light-emitting unit control circuit, when the collecting circuit collects the amount of charge input to the light-emitting unit in a unit time, the switch circuit 30 turns on or off the driving circuit between the driving circuit and the light-emitting unit according to the PWM signal output by the front-end control chip; when the driving circuit is conducted, the current driving current in the driving circuit is increased to a preset driving current, and the current value of the preset driving current is inversely related to the duty ratio of the PWM signal. In this embodiment, the driving circuit between the driving circuit and the light emitting unit is controlled to be turned on or off by the PWM signal and the current driving current in the driving circuit is increased to the preset driving current, so that the amount of charge input to the light emitting unit in a unit time is accurately collected in the low gray state, and the accurate compensation of the light emitting unit is realized.
Referring to fig. 4, fig. 4 is a circuit structure diagram of a light-emitting unit control circuit according to a second embodiment of the light-emitting unit control circuit of the present invention, and a second embodiment of the light-emitting unit control circuit of the present invention is provided based on fig. 4.
In the present embodiment, the switch circuit 30 is disposed between the driving circuit 20 and the light emitting unit.
It should be understood that, according to the above formula of calculating the amount of charge Q = C × I × t, the amount of charge collected can be increased by increasing the capacitance value of the collecting capacitor. In this embodiment, the capacitor includes a capacitor disposed in the pixel unit and a capacitor in the front end control chip. In the process of collecting the electric charge quantity, the driving current firstly charges the capacitor arranged in the pixel unit, then charges the capacitor in the front-end control chip, and the collected electric charge quantity is the electric charge quantity charged by the capacitor in the front-end control chip. Therefore, in the specific collection process, the capacitance value of the capacitor arranged in the pixel unit can be reduced, so that the charge quantity in unit time can be collected more accurately.
Referring to fig. 4, in the present embodiment, the switching circuit 30 includes: a first thin film transistor T1;
the grid electrode of the first thin film transistor T1 is connected with the PWM signal output end of the front end control chip, the source electrode of the first thin film transistor T1 is connected with the output end of the driving circuit 20 and the input end of the acquisition circuit 10, and the drain electrode of the first thin film transistor T1 is connected with the input end of the light emitting unit.
In specific implementation, when the amount of charge in a unit time is collected, the light emitting unit is in a normal driving state, the front end control chip can output a cut-off signal to the gate of the first thin film transistor T1, and stops driving the light emitting unit when the first thin film transistor T1 is cut off, and at this time, the current driving current in the driving circuit 20 can directly charge the capacitor in the front end control chip, so that the amount of charge input to the light emitting unit in the unit time can be accurately collected, and the light emitting unit is accurately compensated.
In fig. 4 and 5, the current driving current may be simultaneously increased to the preset driving current, and then, under the condition of the preset driving current, the charge amount input to the light emitting unit in unit time is collected when the PWM signal is in the invalid duty time, that is, when the first thin film transistor T1 is in the off state. This process both increased the electric current in drive circuit 20, kept apart by the electric capacity with in the pixel cell, promoted the electric charge amount of inputing luminescence unit in the unit interval through drive end electric current and the electric capacity two aspects of isolation pixel cell, can gather more accurate electric charge amount to more accurate compensate luminescence unit.
In a specific implementation, the front-end control chip may output the driving signals Scan1 to the gates of the third thin film transistors T3 to adjust the current driving current in the driving loop to the preset driving current, and then output the PWM signal to the gate of the first thin film transistor T1, and drive the light emitting unit when the first thin film transistor T1 is turned on. And finally, the front-end control chip outputs a collection signal Sensor to a grid electrode of the fifth thin film transistor T5 within the invalid duty ratio time of the PWM signal, and controls the fifth thin film transistor T5 to be conducted, so that more accurate electric charge in unit time is collected under the conditions of presetting drive current and isolating capacitance in the pixel.
In this embodiment, by collecting the amount of charge input to the light emitting unit while isolating the capacitor in the pixel unit, the luminance of the light emitting unit can be accurately compensated according to the amount of charge. In addition, in this embodiment, based on the same circuit structure, the charge amount input to the light emitting unit per unit time is collected within the invalid duty cycle time of the PWM signal and driven by the preset driving current, so that the collected charge amount is improved in two ways, and the light emitting unit is compensated more accurately.
Referring to fig. 6, fig. 6 is a circuit structure diagram of a third embodiment of the light emitting unit control circuit of the present invention. A third embodiment of the light emitting unit control circuit of the present invention is provided based on the first and second embodiments.
In this embodiment, the light emitting unit control circuit further includes: a second thin film transistor T2;
the gate of the second thin film transistor T2 is connected to the front end control chip, the source of the second thin film transistor T2 is connected to a reference power Vref, and the source of the second thin film transistor T2 is connected to the driving circuit 20.
It should be understood that during the scanning of the pixels, it is likely that both ends will be scanned simultaneously, for example, one end will start scanning at a gray level of 255 and the other end will start scanning at a gray level of 0, and the scanning will end at a gray level of 127. For the process of simultaneous scanning at both ends, the currents in the second thin film transistors T2 in the driving circuit 20 for driving the light emitting units are different, and the light emitting units may have image sticking directly due to an excessive change in the current in the second thin film transistors or an excessive change in the current input into the light emitting units in a short time. Because the thin film transistor has a certain hysteresis effect, the current passing through the thin film transistor in forward scanning and reverse scanning changes, and the current passing through the thin film transistor normally changes directly from the current value at the previous moment to the current value at the next moment in the changing process, so that the current value changes too much in a short time to cause afterimage.
The reference power source Vref is a power source for maintaining the gate of the fourth thin film transistor T4 at a constant voltage value. In the gray scale changing process, the initial gray scale value corresponds to an initial voltage, and the target gray scale value corresponds to a target voltage. The precharge voltage provided by the reference power Vref is within a range of the initial voltage and the target voltage. The precharge voltage supplied from the reference power source Vref may be set according to a range of variation of the gray scale value.
In a specific implementation, the front-end control chip controls the connection between the reference power Vref and the gate of the fourth thin film transistor T4 through the fifth thin film transistor T5. The fifth thin film transistor T5 is mainly used for turning on or off a loop between the reference power Vref and the gate of the second thin film transistor T2 according to the pre-charge signal Scan2 output by the front end control chip, and other power transistors having the same function are also applicable, for example, a MOS transistor, a triode, an IGBT, and the like may be adopted, and the invention is not limited specifically here. The front-end control chip may output the driving signal Scan1 to the gate of the third thin film transistor T3 in the driving circuit 20, and control the third thin film transistor T3 to be turned on, at this time, the scanning signal Vdata may provide a certain target voltage to the gate of the fourth thin film transistor T4 through the third thin film transistor T3 in the driving circuit 20, and at this time, the gate of the fourth thin film transistor T4 already has the precharge voltage, and the gate of the fourth thin film transistor T4 is adjusted to the target voltage. When the fourth thin film transistor T4 is turned on, the driving power supply may drive the light emitting cell by outputting the driving voltage PVDD.
In the third embodiment, by providing the second thin film transistor T2 and the reference power source connected to the second thin film transistor T2, the gate of the fourth thin film transistor T4 is provided with a certain voltage, so that the hysteresis effect of the fourth thin film transistor T4 can be effectively reduced, and therefore, the luminance of the light emitting unit can be accurately compensated while the afterimage of the light emitting unit can be avoided.
Referring to fig. 7, fig. 7 is a flowchart illustrating a method for controlling a light emitting unit according to a first embodiment of the present invention. Based on the disclosure of fig. 7, a first embodiment of a method for controlling a light emitting unit according to the present invention is provided.
Referring to fig. 7, a light emitting unit control method in a first embodiment of the light emitting unit control method includes:
step S10: when the acquisition circuit acquires the charge quantity input into the light-emitting unit in unit time, the switch circuit switches on or off a driving loop between the driving circuit and the light-emitting unit according to a PWM (pulse width modulation) signal output by a front-end control chip;
step S20: when the driving circuit is conducted, the driving circuit raises the current driving current in the driving circuit to a preset driving current to drive the light-emitting unit, and the current value of the preset driving current is inversely related to the duty ratio of the PWM signal.
The switch circuit is a circuit for controlling whether the driving circuit between the driving power supply and the light emitting unit is turned on. The switch circuit may be a current composed of a power transistor and other related components, and the specific structure of the switch circuit is not limited in this embodiment. The front-end control chip is used for controlling the driving and compensation of the light-emitting unit, and can control the connection or disconnection of each loop by inputting related driving signals to the switching elements in each loop. The front-end control chip can adjust the opening degree of the first thin film transistor and the second thin film transistor by adjusting the voltage value of the driving signal, so as to adjust the driving current in the driving circuit, and the front-end control chip is not shown in the figure. The light emitting unit may be a pixel, and the light emitting unit may be composed of a first organic light emitting diode, a second capacitor, and other related components, and the connection of other elements is not specifically limited herein.
In a specific implementation, when the charge amount is collected, the front-end control chip firstly outputs a driving signal to the gate of the third thin film transistor to control the third thin film transistor to be conducted, so that the scanning voltage is input to the gate of the fourth thin film transistor to control the fourth thin film transistor to be conducted. Then the front end control chip can output PWM signals to the switch circuit, and the switch circuit conducts a driving loop between the driving circuit and the light-emitting unit within the effective duty ratio time of the PWM signals according to the PWM signals output by the front end control chip; when the driving circuit is conducted, the current driving current provided by the driving voltage is increased to the preset driving current to drive the light-emitting unit, and finally the front-end control chip outputs a collecting signal to the grid electrode of the fifth thin film transistor to conduct the fifth thin film transistor, so that the electric charge quantity input into the light-emitting unit in unit time is collected. Here, the driving time within a single frame is controlled by the PWM signal while increasing the current value in the driving circuit, thereby ensuring that the luminance of the light emitting unit remains unchanged.
The preset driving current is a current with a larger preset current value. The current value of the preset driving current is inversely related to the duty ratio of the PWM signal. When the light emitting unit is driven at a rated current, the larger the duty ratio of the PWM signal is, the larger the luminance of the light emitting unit is, and the larger the gray scale value of the pixel is. In this embodiment, in order to ensure that the total charge amount input to the light emitting unit per unit time is not changed, the larger the current value of the preset driving current is, the smaller the duty ratio of the corresponding PWM signal is, thereby maintaining the gray-scale value of the pixel.
In a first embodiment of the light-emitting unit control circuit, when the collecting circuit collects the charge quantity input to the light-emitting unit in a unit time, the switching circuit switches on or off a driving loop between the driving circuit and the light-emitting unit according to a PWM signal output by a front-end control chip; when the driving circuit is conducted, the current driving current in the driving circuit is increased to a preset driving current, and the current value of the preset driving current is inversely related to the duty ratio of the PWM signal. In this embodiment, the driving circuit between the driving circuit and the light emitting unit is controlled to be turned on or off by the PWM signal and the current driving current in the driving circuit is increased to the preset driving current, so that the amount of charge input to the light emitting unit in a unit time is accurately collected in a low gray state, and the light emitting unit is accurately compensated.
Referring to fig. 8, fig. 8 is a flowchart illustrating a second method for controlling a light emitting unit according to an embodiment of the present invention. Based on the above embodiment of the method for controlling a light emitting unit of the present invention, a second embodiment of the method for controlling a light emitting unit of the present invention is provided.
In this embodiment, before the step S10, the method further includes:
step S101: the acquisition circuit acquires the current driving charge quantity generated by the current driving current for driving the light-emitting unit in unit time;
it should be noted that, when the current driving current is in the normal state, the driving power supply outputs a current for driving the light emitting unit. The current driving charge amount refers to a charge amount input to the light emitting cell per unit time. In the present embodiment, the present driving charge amount may be determined by the amount of charge for charging the capacitance in the front-end control chip by passing the present driving current through the capacitance in the front-end control chip.
Step S102: the front-end control chip determines the current gray-scale value of the light-emitting unit according to the current driving charge quantity;
it should be noted that the current gray-scale value is used to represent the brightness parameter of the light-emitting unit in the current state. The brightness of the light emitting unit at this time can be determined according to the current driving charge amount to determine the current gray-scale value of the light emitting unit. In a specific implementation, a relationship between a current driving charge amount and luminance of the light emitting unit may be determined according to characteristics of the light emitting unit, and then a current gray-scale value of the light emitting unit may be determined according to the charge amount.
Step S103: and the front-end control chip outputs a PWM signal when the current gray-scale value is lower than a preset gray-scale value.
It should be noted that the preset gray-scale value is a preset gray-scale value for determining the light-emitting state of the light-emitting unit. When the current gray scale value is lower than the preset gray scale value, the light-emitting unit is in a low gray scale state. The front end control chip can output a PWM signal to control the charge quantity input into the light-emitting unit in unit time by controlling the state of the first thin film transistor when the light-emitting unit is in a low gray scale state.
In this embodiment, after the step S20, the method further includes:
step S30: and the acquisition circuit acquires the preset driving charge quantity generated by the preset driving current in unit time when the driving circuit is disconnected.
Note that the preset driving charge amount is an amount of charge that the preset driving current is input to the light emitting cell per unit time. In a specific implementation, the front-end control chip may output a driving signal to the gate of the third thin film transistor to adjust a current driving current in the driving circuit to a preset driving current, and then output a PWM signal to the gate of the first thin film transistor, so as to drive the light emitting unit when the first thin film transistor is turned on. And finally, the front-end control chip outputs a collecting signal to a grid electrode of the fifth thin film transistor within the invalid duty ratio time of the PWM signal, and controls the fifth thin film transistor to be conducted, so that more accurate electric charge in unit time is collected under the conditions of presetting drive current and isolating the capacitance in the pixel.
In the embodiment, the amount of charge input to the light emitting unit per unit time is collected within the invalid duty cycle time of the PWM signal and driven by the preset driving current, and the collected amount of charge is improved in two aspects, so that the light emitting unit is more accurately compensated.
Referring to fig. 9, fig. 9 is a flowchart illustrating a third method for controlling a light emitting unit according to an embodiment of the present invention. Based on fig. 9, a third embodiment of the method for controlling a light emitting unit of the present invention is provided.
In this embodiment, the light emitting unit control method includes:
step S10': the driving circuit drives the light-emitting unit according to the current driving current when the acquisition circuit acquires the charge quantity input to the light-emitting unit in unit time;
step S20': and the switch circuit disconnects a driving loop between the driving circuit and the light-emitting unit according to a cut-off signal output by the front-end control chip.
It should be noted that, in the process of collecting the charge amount, the driving current may first charge the capacitor disposed in the pixel unit, and then charge the capacitor in the front-end control chip, where the collected charge amount is the charge amount charged by the capacitor in the front-end control chip. Therefore, in the specific collecting process, the capacitance value of the capacitor arranged in the pixel unit can be reduced, and the electric charge quantity in unit time can be collected more accurately.
In specific implementation, the light-emitting unit is in a normal driving state when the electric charge in unit time is collected, the front-end control chip can output a cut-off signal to the grid electrode of the first thin film transistor firstly, the light-emitting unit is stopped being driven when the first thin film transistor is cut off, and the current driving current in the driving circuit can directly charge the capacitor in the front-end control chip at the moment, so that the electric charge input to the light-emitting unit in unit time can be accurately collected, and the light-emitting unit is accurately compensated.
In this embodiment, by collecting the amount of charge input to the light emitting unit while isolating the capacitor in the pixel unit, the luminance of the light emitting unit can be accurately compensated according to the amount of charge.
In addition, the invention also provides an array substrate which comprises a light-emitting unit and the light-emitting unit control circuit. Since the array substrate adopts all the technical solutions of all the embodiments, at least all the beneficial effects brought by the technical solutions of the embodiments are achieved, and details are not repeated herein.
In addition, the present invention further provides a display panel, referring to fig. 10, fig. 10 is a schematic structural diagram of an embodiment of the display panel of the present application, where the display panel includes the array substrate 40 and a light-emitting layer 50, and the light-emitting layer 50 is disposed on the array substrate 40.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
It should be apparent that the described embodiments are only some of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.
It should be noted that all directional indicators (such as up, down, left, right, front, back \8230;) in the embodiments of the present invention are only used to explain the relative positional relationship between the components, the motion situation, etc. in a specific posture (as shown in the attached drawings), and if the specific posture is changed, the directional indicator is changed accordingly.
In addition, the descriptions related to "first", "second", etc. in the present invention are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should be considered to be absent and not within the protection scope of the present invention.
Claims (7)
1. A light-emitting unit control circuit comprises an acquisition circuit and a drive circuit, wherein the acquisition circuit is connected with the drive circuit and a front-end control chip which is connected with a light-emitting unit through the drive circuit;
the switch circuit is used for switching on or off a driving loop between the driving circuit and the light-emitting unit according to a PWM signal output by the front-end control chip when the acquisition circuit acquires the electric charge quantity input to the light-emitting unit in unit time;
the driving circuit is used for increasing the current driving current in the driving circuit to a preset driving current when the driving circuit is conducted, wherein the current value of the preset driving current is inversely related to the duty ratio of the PWM signal, and the gray-scale value of a pixel in the light-emitting unit is maintained;
the switch circuit is arranged between the drive circuit and the light-emitting unit;
the switching circuit includes: a first thin film transistor;
the grid electrode of the first thin film transistor is connected with the PWM signal output end of the front-end control chip, the source electrode of the first thin film transistor is connected with the output end of the driving circuit and the input end of the acquisition circuit, and the drain electrode of the first thin film transistor is connected with the input end of the light-emitting unit;
the acquisition circuit is used for acquiring the quantity of electric charges input into the light-emitting unit in unit time within the invalid duty cycle time of the PWM signal.
2. The light-emitting-unit control circuit according to claim 1, further comprising: a second thin film transistor;
the grid electrode of the second thin film transistor is connected with the front-end control chip, the drain electrode of the second thin film transistor is connected with a reference power supply, and the source electrode of the second thin film transistor is connected with the driving circuit.
3. A light emitting unit control method based on the light emitting unit control circuit according to any one of claims 1 to 2, wherein the light emitting unit control method comprises:
when the acquisition circuit acquires the charge quantity input into the light-emitting unit in unit time, the switching circuit switches on or off a driving loop between the driving circuit and the light-emitting unit according to a PWM (pulse width modulation) signal output by a front-end control chip;
when the driving circuit is conducted, the driving circuit raises the current driving current in the driving circuit to a preset driving current to drive the light-emitting unit, wherein the current value of the preset driving current is negatively related to the duty ratio of the PWM signal, and the gray-scale value of a pixel in the light-emitting unit is maintained;
when the driving circuit is turned on, after the step of increasing the current driving current in the driving circuit to the preset driving current to drive the light emitting unit, the method further includes:
and the acquisition circuit acquires the preset driving charge quantity generated by the preset driving current in unit time when the driving circuit is disconnected.
4. The light emitting unit control method according to claim 3, wherein before the step of turning on or off the driving circuit between the driving circuit and the light emitting unit according to the PWM signal output from the front end control chip, further comprising:
the acquisition circuit acquires the current driving charge quantity generated by the current driving current for driving the light-emitting unit in unit time;
the front-end control chip determines the current gray-scale value of the light-emitting unit according to the current driving charge quantity;
and the front-end control chip outputs a PWM signal when the current gray-scale value is lower than a preset gray-scale value.
5. A light emitting unit control method according to claim 3, characterized in that the light emitting unit control method comprises:
the driving circuit drives the light-emitting unit according to the current driving current when the acquisition circuit acquires the charge quantity input to the light-emitting unit in unit time;
and the switch circuit disconnects a driving loop between the driving circuit and the light-emitting unit according to a cut-off signal output by the front-end control chip.
6. An array substrate, comprising: a light emitting unit and a light emitting unit control circuit as claimed in any one of claims 1-2.
7. A display panel comprising the array substrate of claim 6 and a light-emitting layer disposed on the array substrate.
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| CN202111650710.5A CN114241991B (en) | 2021-12-29 | 2021-12-29 | Light-emitting unit control circuit, method, array substrate and display panel |
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| CN202111650710.5A CN114241991B (en) | 2021-12-29 | 2021-12-29 | Light-emitting unit control circuit, method, array substrate and display panel |
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| CN114241991B true CN114241991B (en) | 2022-10-18 |
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| CN206877668U (en) * | 2017-05-26 | 2018-01-12 | 维沃移动通信有限公司 | A kind of brightness of display screen regulation circuit and mobile terminal |
| CN110910816B (en) * | 2019-11-11 | 2021-01-15 | 深圳市华星光电半导体显示技术有限公司 | Pixel driving circuit and display panel |
| CN113192462A (en) * | 2020-01-14 | 2021-07-30 | 京东方科技集团股份有限公司 | Pixel circuit, display substrate, display device and pixel driving method |
| CN111210765B (en) * | 2020-02-14 | 2022-02-11 | 华南理工大学 | Pixel circuit, driving method of pixel circuit and display panel |
| CN112927651B (en) * | 2021-02-05 | 2022-05-24 | 华南理工大学 | Pixel driving circuit, active electroluminescent display and driving method |
| CN113270071A (en) * | 2021-05-28 | 2021-08-17 | 长沙惠科光电有限公司 | External compensation pixel circuit and display panel |
| CN113611248B (en) * | 2021-08-11 | 2023-08-11 | 合肥京东方卓印科技有限公司 | Display panel, driving method of switch circuit of display panel and display device |
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