CN113112958B - Pixel driving circuit and display panel - Google Patents
Pixel driving circuit and display panel Download PDFInfo
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- CN113112958B CN113112958B CN202110361372.7A CN202110361372A CN113112958B CN 113112958 B CN113112958 B CN 113112958B CN 202110361372 A CN202110361372 A CN 202110361372A CN 113112958 B CN113112958 B CN 113112958B
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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]
- G09G3/3225—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
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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]
- G09G3/3225—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
- G09G3/3258—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix with pixel circuitry controlling the voltage across the light-emitting element
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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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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
- Electroluminescent Light Sources (AREA)
Abstract
The invention provides a pixel driving circuit and a display panel, wherein a charge absorption module of the pixel driving circuit comprises a voltage comparison unit and a control unit which are connected, the output end of the control unit is connected with an induction signal line of a sub-pixel circuit and a comparison signal input end of the voltage comparison unit, the comparison signal input end of the voltage comparison unit is used for acquiring the detection voltage of the induction signal line, when the detection voltage is greater than a reference voltage, the output end of the voltage comparison unit outputs a low-voltage signal, the induction signal line is grounded through the charge absorption module to release the charge of the horizontal crosstalk of the induction signal line, until the reference voltage is equal to the detection voltage, a supply voltage input end of the control unit outputs a reference voltage to the output end of the control unit, so that the Vs voltage of the drain electrode of each driving thin film transistor is ensured to be stable, namely the initial voltage difference between Vg and Vs of the grid electrode of each driving thin film transistor is the same, thereby improving the uniformity of each sub-pixel display.
Description
Technical Field
The invention relates to the technical field of display, in particular to a pixel driving circuit and a display panel.
Background
An existing AMOLED (Active Matrix Organic Light Emitting Diode) display panel is thinner and lighter than a liquid crystal display panel, and thus has a wide application. At present, a 3T1C pixel circuit architecture is usually adopted for the development of a large-size AMOLED panel, in a display frame period, high voltage is input to a scanning line and a sensing line, a switching transistor and a detection transistor are turned on, a gate voltage Vg of the driving transistor is written into a Data voltage Data, an output end voltage Vs of the driving transistor is written into a reference voltage VREF, then the scanning line and the sensing line are cut back to low voltage, the driving transistor maintains on based on a storage capacitor Cst, a light emitting device emits light until a voltage difference Vgs provided by the capacitor Cst is reduced to 0, in a display frame period, the current flow direction of the light emitting device OLED is from a positive electrode Vs to a negative electrode VSS, and the light emitting device OLED emits light.
As shown in fig. 1, the red sub-pixel 1, the green sub-pixel 2 and the blue sub-pixel 3 in adjacent columns are electrically connected to the sensing line Sense-line 4 at the same time. As shown in fig. 2, when the Data voltage Data is written, the Vs voltage is high in the pixel circuit of the green sub-pixel 2 (high gray scale) region, the Vs voltage is low in the pixel circuits of the red sub-pixel 1 and the blue sub-pixel 3 (low gray scale) region on both sides of the green sub-pixel 2, when Vs is simultaneously connected to the reference voltage VREF, and the Sense-line 4 has a weak ability to absorb charges, charges provided by the reference voltage VREF of the drain of the driving tft of the green sub-pixel 2 flow to both sides, so that the voltages of the drains of the driving tfts of the red sub-pixel 1 and the blue sub-pixel 3 at both sides are higher than the actual reference voltage VREF, and finally, the voltage difference between the two ends of the storage capacitor of the red sub-pixel 1 and the blue sub-pixel 3 is smaller than the voltage difference between the two ends of the storage capacitor of the green sub-pixel 2, and the display luminance of the red sub-pixel 1, the green sub-pixel 2, and the blue sub-pixel 3 is not uniform.
In summary, it is desirable to provide a pixel driving circuit and a display panel to solve the above-mentioned problems that the sense-line provides the reference voltage VREF and has no ability to absorb charges, which may cause crosstalk to the drain point charges of the driving tfts of the sub-pixels connected in parallel, thereby seriously affecting the display effect.
Disclosure of Invention
The invention provides a pixel driving circuit and a display panel, which can solve the problem that in the prior art, a sense-line provides a reference voltage VREF, and the ability of absorbing charges is not available, so that crosstalk is generated on drain point charges of driving thin film transistors of sub-pixels connected in parallel, and the display effect is seriously influenced.
The technical scheme provided by the invention is as follows:
the embodiment of the invention provides a pixel driving circuit, which comprises at least three sub-pixel driving circuits, wherein the at least three sub-pixel driving circuits are connected through an induction signal line, and a signal input end of the induction signal line is provided with a charge absorption module;
the charge absorption module comprises a voltage comparison unit and a control unit which are connected;
the voltage comparison unit comprises a reference signal input end, a comparison signal input end and a first output end;
the control unit comprises a supply voltage input end, a control signal input end and a second output end; the second output end of the control unit is connected with the induction signal wire and the comparison signal input end of the voltage comparison unit; and the first output end of the voltage comparison unit is connected with the control signal input end of the control unit.
According to a preferred embodiment of the present invention, the control unit includes a first thin film transistor, a second thin film transistor, and a resistor module, wherein a source of the first thin film transistor is electrically connected to a voltage supply input terminal of the control unit, a drain of the first thin film transistor is electrically connected to a source of the second thin film transistor, a drain of the first thin film transistor and a source of the second thin film transistor are both electrically connected to a second output terminal of the control unit, a drain of the first thin film transistor is grounded through the resistor module, a gate of the first thin film transistor is electrically connected to a gate of the second thin film transistor, and a gate of the first thin film transistor and a gate of the second thin film transistor are both electrically connected to a control signal input terminal of the control unit.
According to a preferred embodiment of the present invention, a comparison signal input terminal of the voltage comparison unit is configured to obtain a detected voltage of the sensing signal line, and a reference signal input terminal of the voltage comparison unit is configured to input a reference voltage;
when the detection voltage is greater than the reference voltage, a first output end of the voltage comparison unit outputs a low-voltage signal, the first thin film transistor is turned off, the second thin film transistor is turned on, the sensing signal line is grounded through a comparison signal input end of the voltage comparison unit, the second thin film transistor and the resistance module, and crosstalk charges fed back in the sub-pixel driving circuit are grounded until the detection voltage is equal to the reference voltage;
when the detection voltage is equal to the reference voltage, a first output end of the voltage comparison unit outputs a high-voltage signal, the second thin film transistor is closed, the first thin film transistor is conducted, and a supply voltage input end of the control unit outputs the reference voltage to a second output end of the control unit through the first thin film transistor.
According to a preferred embodiment of the present invention, the first thin film transistor is an N-type thin film transistor, the second thin film transistor is a P-type thin film transistor, and the resistor module is one or more of a reactance, an inductor, and a resistor.
According to a preferred embodiment of the present invention, the reference voltage is a constant voltage signal.
According to a preferred embodiment of the present invention, the sub-pixel driving circuit is a 3T1C pixel circuit, and includes a third thin film transistor, a fourth thin film transistor, a fifth thin film transistor, a storage capacitor Cst, and an OLED device, wherein a gate of the third thin film transistor is electrically connected to the first scan line, a source of the third thin film transistor is electrically connected to the data signal, and a drain of the third thin film transistor is electrically connected to the first node; the grid electrode of the fourth thin film transistor is electrically connected with the first node, the source electrode of the fourth thin film transistor is electrically connected with the positive voltage of the power supply, and the drain electrode of the fourth thin film transistor is electrically connected with the second node and the OLED device; a grid electrode of the fifth thin film transistor is electrically connected with the second scanning line, a source electrode of the fifth thin film transistor is electrically connected with the second node, and a drain electrode of the fifth thin film transistor is electrically connected with the second output end of the control unit through the induction signal line; a storage capacitor Cst is disposed between the first node and the second node.
According to a preferred embodiment of the present invention, the sub-pixel driving circuit further includes an ADC module and a single-pole double-throw switch, a drain of the fifth thin film transistor is electrically connected to a fixed end of the single-pole double-throw switch, the ADC module and the sensing signal line are respectively electrically connected to two movable ends of the single-pole double-throw switch, and the ADC module is configured to obtain a threshold voltage of the fourth thin film transistor.
According to a preferred embodiment of the present invention, during the display time of the display frame period, the single-pole double-throw switch is electrically connected to the sensing signal line, and the single-pole double-throw switch is disconnected from the ADC module; and in the non-display time of the display frame period or the non-display frame period, the single-pole double-throw switch is electrically connected with the ADC module, and the single-pole double-throw switch is disconnected with the induction signal line.
According to a preferred embodiment of the present invention, at least three horizontally disposed sub-pixel driving circuits are electrically connected to one of the charge draining modules through the same sensing signal line, and each of the sub-pixel driving circuits is individually provided with one of the ADC modules.
According to the pixel driving circuit, the invention further provides a display panel including the pixel driving circuit of the above embodiment.
The invention has the beneficial effects that: the embodiment of the invention provides a pixel driving circuit and a display panel, wherein the pixel driving circuit comprises at least three sub-pixel driving circuits which are connected through an induction signal line, and a signal input end of the induction signal line is provided with a charge absorption module; the charge absorption module comprises a voltage comparison unit and a control unit which are connected; the voltage comparison unit comprises a reference signal input end, a comparison signal input end and a first output end; the control unit comprises a supply voltage input end, a control signal input end and a second output end; the second output end of the control unit is connected with the induction signal line and the comparison signal input end of the voltage comparison unit; and the first output end of the voltage comparison unit is connected with the control signal input end of the control unit. A comparison signal input end of the voltage comparison unit is used for acquiring the detection voltage of the induction signal line, and a reference signal input end of the voltage comparison unit is used for introducing reference voltage; when the detection voltage is greater than the reference voltage, the first output end of the voltage comparison unit outputs a low-voltage signal, the induction signal line is grounded through the charge absorption module, the horizontal crosstalk charge of the induction signal line is released, and the supply voltage input end of the control unit outputs the reference voltage to the second output end of the control unit through the first thin film transistor until the reference voltage is equal to the detection voltage, so that the Vs voltage of the drain electrode of the driving thin film transistor of each sub-pixel driving circuit is stable, namely the initial voltage difference Vgs between the grid Vg and Vs of each driving thin film transistor is the same, and the display uniformity of each sub-pixel is improved.
Drawings
In order to illustrate the embodiments or the technical solutions in the prior art more clearly, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the invention, and it is obvious for a person skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic diagram illustrating connection between a sensing line and a sub-pixel in a pixel driving circuit in the prior art.
FIG. 2 is a diagram illustrating the display effect of three adjacent sub-pixels in the prior art.
Fig. 3 is a schematic diagram of a driving circuit of a display device in the prior art.
Fig. 4 is a circuit connection diagram of a pixel driving circuit according to the present invention.
Fig. 5 is a circuit connection diagram of a charge draining module in a pixel driving circuit according to the present invention.
Detailed Description
The following description of the various embodiments refers to the accompanying drawings that illustrate specific embodiments in which the invention may be practiced. The directional terms mentioned in the present invention, such as [ upper ], [ lower ], [ front ], [ rear ], [ left ], [ right ], [ inner ], [ outer ], [ side ], are only referring to the directions of the attached drawings. Accordingly, the directional terms used are used for explanation and understanding of the present invention, and are not used for limiting the present invention. In the drawings, elements having similar structures are denoted by the same reference numerals, and broken lines in the drawings indicate that the elements do not exist in the structures, and only the shapes and positions of the structures are explained.
The invention aims at the problem that the drain point charges of the driving thin film transistors of the parallel sub-pixels can generate crosstalk to seriously influence the display effect because the sensing lines sense-line in the prior art provide the reference voltage VREF and have no charge absorption capacity, and the defect can be solved by the embodiment.
As shown in fig. 3, the conventional display device includes a display panel 10, a power supply module 11, a control board 12, a scan driver 13, a data driver 15, and a feedback module 17. After the display device system EL _ ON is turned ON, the power module 11 provides power to the control board 12, the scan driver 13, the data driver 15 and the display panel 10, and specifically, the power module 11 provides voltages such as Vdd, Vss, VREF and Vinit to the pixel units of the display panel 10. The control board 12 is provided with a video signal access port, a circuit board, and a timing controller, which supplies a gray scale value and a control signal to the data driver 15. In addition, the timing controller supplies a clock signal, a start trigger signal, and a same-level scan signal to the scan driver 13. The data driver 15 generates data signals 16 to be supplied to the data lines from the gray scale values and the control signals received from the timing controller. For example, the data driver 15 may sample gray-scale values using a clock signal and apply data voltages corresponding to the gray-scale values to the data lines D1 to Dn as data signals. Here, n may be a natural number greater than zero.
The scan driver 13 may receive a clock signal, a scan start signal, and the like from the timing controller, and generate scan signals to be supplied to the scan lines S1, S2, S3 to Sm. For example, the scan driver 13 may sequentially supply the scan signals 14, each having an on-level pulse, to the scan lines S1 to Sm. For example, the scan driver 13 may take the form of a shift register, and may generate scan signals such that scan start signals in the form of on horizontal pulses are sequentially delivered to the next stage circuit under the control of a clock signal. Here, m may be a natural number greater than zero.
The feedback module 17 collects the brightness of the pixel units P in the display panel, and compares the brightness difference of each pixel unit P to compensate the current value of the corresponding pixel unit P flowing through the light emitting device. For example, the feedback module 17 may be an ADC module, which detects the change of the threshold voltage of the driving thin film transistor, and dynamically drives the data voltage on the gate and the reference voltage value on the drain of the thin film transistor according to the threshold of the driving thin film transistor, so as to compensate the current value flowing through the light emitting device in the pixel, thereby achieving the display uniformity of the display panel.
The display panel 10 includes pixel units P arranged in an array. Each pixel circuit P may be coupled to a data line, a scan line, and a power line corresponding thereto. A pixel driving circuit is provided in the pixel unit P. Because at least 3 adjacent rows of red pixel units, green pixel units and blue pixel units are simultaneously connected to sense lines sense-line of respective pixel circuits, when a data signal is written, charges on the sense lines of the middle pixel unit flow to the sense lines of the pixel units on two sides, if the ability of the sense lines to absorb crosstalk charges is weak, the voltage difference between two ends of the storage capacitors of the pixel units on two sides is smaller than that between two ends of the storage capacitors of the middle pixel unit, and the display brightness of the adjacent 3 rows of pixel units is not uniform.
In order to solve the above technical problem, the present invention provides a pixel driving circuit, which includes at least three sub-pixel driving circuits connected by an inductive signal line, wherein a signal input end of the inductive signal line is provided with a charge absorption module; the charge absorption module comprises a voltage comparison unit and a control unit which are connected; the voltage comparison unit comprises a reference signal input end, a comparison signal input end and a first output end; the control unit comprises a supply voltage input end, a control signal input end and a second output end; the second output end of the control unit is connected with the induction signal line and the comparison signal input end of the voltage comparison unit; and the first output end of the voltage comparison unit is connected with the control signal input end of the control unit. A comparison signal input end of the voltage comparison unit is used for acquiring the detection voltage of the induction signal line, and a reference signal input end of the voltage comparison unit is used for introducing reference voltage; when the detection voltage is greater than the reference voltage, the first output end of the voltage comparison unit outputs a low-voltage signal, the sensing signal line is grounded through the charge absorption module, the horizontal crosstalk charge of the sensing signal line is released until the reference voltage is equal to the detection voltage, and the supply voltage input end of the control unit outputs the reference voltage to the second output end of the control unit through the first thin film transistor, so that the voltage stability of the detection end of the sub-pixel driving circuit is ensured, and the uniformity of display of each sub-pixel is improved.
Specifically, as shown in fig. 4, the present embodiment takes three horizontal sub-pixel driving circuits as an example to illustrate the invention, and the three horizontal sub-pixels a/B/C are R/G/B sub-pixels respectively. Each sub-pixel driving circuit is preferably a 3T1C pixel circuit, and the sub-pixel driving circuits in other embodiments may also be other types of pixel driving circuits, which are not limited herein. The sub-pixel driving circuit of the present embodiment is a 3T1C pixel circuit, and includes a third thin film transistor T3, a fourth thin film transistor T4, a fifth thin film transistor T5, a storage capacitor Cst, and an OLED device, and the third thin film transistor T3, the fourth thin film transistor T4, and the fifth thin film transistor T5 are preferably N-type thin film transistors.
The gate of the third thin film transistor T3 is electrically connected to the first scan line WR, the source of the third thin film transistor T3 is electrically connected to the data signal, the drain of the third thin film transistor T3 is electrically connected to the first node (Vg position), and the third thin film transistor T3 functions as a switching thin film transistor; the gate of the fourth thin film transistor T4 is electrically connected to the first node (Vg position), the source of the fourth thin film transistor T4 is electrically connected to the power supply positive voltage Vdd, the drain of the fourth thin film transistor T4 is electrically connected to the second node (Vs position) and the OLED device, and the fourth thin film transistor T4 functions as a driving thin film transistor; the gate of the fifth thin film transistor T5 is electrically connected to the second scan line Wn, the source of the fifth thin film transistor T5 is electrically connected to the second node (Vs position), a storage capacitor Cst is disposed between the first node (Vg position) and the second node (Vs position), the drain of the fifth thin film transistor T5 is electrically connected to the sensing signal line 201, the drains of the fifth thin film transistors T5 of the other sub-pixels are also electrically connected to the sensing signal line 201, the signal input terminal of the sensing signal line 201 is provided with the charge absorbing module 20, and the fifth thin film transistor T5 plays a role of detecting the thin film transistor.
As shown in fig. 5, the charge draining module 20 includes a voltage comparing unit 21 and a control unit 22 connected; the voltage comparison unit 21 includes a reference signal input terminal 211, a comparison signal input terminal 212 and a first output terminal 213, the reference signal input terminal 211 is a positive terminal of the voltage comparison unit 21, and the comparison signal input terminal 212 is a negative terminal of the voltage comparison unit 21. The control unit 22 comprises a voltage input terminal 221(VREF-IN), a control signal input terminal 222 and a second output terminal 223 (VREF-OUT), wherein the second output terminal 223 of the control unit 22 is connected with the sensing signal line 201 (see fig. 4) and the comparison signal input terminal 212 of the voltage comparison unit 21; and the first output terminal 213 of the voltage comparing unit 21 is connected to the control signal input terminal 222 of the control unit 22. If there is no charge fed back from the sub-pixel driving circuit on the sensing signal line 201, the voltage on the sensing signal line 201 is the reference voltage VREF input by the supply voltage input terminal 221(VREF-IN) of the control unit 22, and if there is charge fed back from the sub-pixel driving circuit on the sensing signal line 201, the real voltage on the sensing signal line 201 is the superimposed voltage of the reference voltage input by the supply voltage input terminal 221(VREF-IN) of the control unit 22 and the crosstalk charge, and the voltage is greater than the reference voltage, which may cause the voltages of the detection terminals of other sub-pixel driving circuits to increase, resulting IN non-uniform display of the corresponding sub-pixel driving circuit.
The control unit 22 includes a first thin film transistor T1, a second thin film transistor T2 and a resistor module R, a source of the first thin film transistor T1 is electrically connected to the voltage supply input 221 of the control unit 22, a drain of the first thin film transistor T1 is electrically connected to a source of the second thin film transistor T2, a drain of the first thin film transistor T1 and a source of the second thin film transistor T2 are both electrically connected to the second output 223 of the control unit 22, a drain of the first thin film transistor T1 is grounded through the resistor module R, a gate of the first thin film transistor T1 is electrically connected to a gate of the second thin film transistor T2, and a gate of the first thin film transistor T1 and a gate of the second thin film transistor T2 are both electrically connected to the control signal input 222 of the control unit 22, so that the first thin film transistor T1 and the second thin film transistor T2 form an inverter, in this embodiment, the first thin film transistor T1 is an N-type thin film transistor, the second thin film transistor T2 is a P-type thin film transistor, and the resistor module R is one or more of a reactance, an inductor, and a resistor.
The comparison signal input terminal 212 of the voltage comparison unit 21 of the present embodiment is used for obtaining the magnitude of the detection voltage of the sensing signal line 201 (see fig. 4), and the reference signal input terminal 211 of the voltage comparison unit 21 is used for inputting a reference voltage, which is preferably a constant voltage signal. When the detected voltage on the sensing signal line 201 obtained at the comparison signal input terminal 212 is 1 to 1 with the real voltage on the sensing signal line 201, the reference voltage is preferably equal to the reference voltage input by the supply voltage input terminal 221 of the control unit 22.
When the detection voltage is greater than the reference voltage, the first output terminal 213 of the voltage comparing unit 21 outputs a low voltage signal, the first thin film transistor T1 is turned off, the second thin film transistor T2 is turned on, the sensing signal line 201 is grounded through the comparison signal input terminal 212 of the voltage comparing unit 21, the second thin film transistor T2 and the resistor module R, and the crosstalk charges fed back from the sub-pixel driving circuit are grounded until the detection voltage is equal to the reference voltage.
When the detection voltage is equal to the reference voltage, the first output terminal 213 of the voltage comparing unit 21 outputs a high voltage signal, the second thin film transistor T2 is turned off, the first thin film transistor T1 is turned on, the supply voltage input terminal 221 of the control unit 22 outputs a reference voltage to the second output terminal 223 of the control unit 22 through the first thin film transistor T1, that is, the voltages of the second nodes (Vs positions) of the respective sub-pixel driving circuits are all the reference voltages, it is ensured that the initial voltage differences Vgs between the gate Vg and the drain Vs of the respective driving thin film transistors T1 are the same, it is ensured that the charging and discharging time of the storage capacitor Cst is the same, and the display time in the display frame period is the same, thereby ensuring the display uniformity of the pixels.
In another embodiment, the comparison signal input end 212 of the voltage comparison unit 21 is configured to obtain a magnitude of the detection voltage of the sensing signal line 201 (see fig. 4), when the detection voltage on the sensing signal line 201 obtained by the comparison signal input end 212 and the voltage on the sensing signal line 201 are n to 1, n is a certain exact value, the reference voltage is preferably equal to n times the reference voltage input by the supply voltage input end 221 of the control unit 22, other structures and circuit connections are the same as those in the above-mentioned embodiment, and the comparison manner is slightly different, and will not be described herein again.
As shown in fig. 4, each sub-pixel driving circuit further includes an ADC module and a single-pole double-throw switch, a drain of a fifth thin film transistor of each sub-pixel driving circuit is electrically connected to a fixed end of the single-pole double-throw switch, the ADC module and the sensing signal line 201 are electrically connected to two movable ends of the single-pole double-throw switch, respectively, and the ADC module is configured to obtain a threshold voltage of a fourth thin film transistor. In the display time of the display frame period, the single-pole double-throw switch is electrically connected with the induction signal line, and the single-pole double-throw switch is disconnected with the ADC module; and in the non-display time of the display frame period or the non-display frame period, the single-pole double-throw switch is electrically connected with the ADC module, and the single-pole double-throw switch is disconnected with the induction signal line. In this embodiment, at least three horizontally disposed sub-pixel driving circuits are electrically connected to a charge absorption module through a same sensing line, and each sub-pixel driving circuit is individually provided with an ADC module.
A signal line L1 of the drain of the fifth thin film transistor T5 in the subpixel driving circuit a is disposed at a fixed end of the single-pole double-throw switch S1, the sensing line SL1 and the ADC1 module are respectively fixed at two side moving ends of the single-pole double-throw switch S1, a signal line L2 of the drain of the fifth thin film transistor T5 in the subpixel driving circuit B is disposed at a fixed end of the single-pole double-throw switch S2, the sensing line SL2 and the ADC2 module are respectively fixed at two side moving ends of the single-pole double-throw switch S2, a signal line L3 of the drain of the fifth thin film transistor T5 in the subpixel driving circuit C is disposed at a fixed end of the single-pole double-throw switch S3, the sensing line SL3 and the ADC2 module are respectively fixed at two side moving ends of the single-pole double-throw switch S3, and the sensing line SL1, the sensing line 2 and the sensing line SL3 are all electrically connected to the sensing signal line 201.
Taking the open-close state of the single-pole double-throw switch S1 in the sub-pixel driving circuit a as an example, during the display time of the display frame period, the single-pole double-throw switch S1 is electrically connected to the sensing line SL1, and the single-pole double-throw switch S1 is disconnected from the ADC1 module; in the non-display time of the display frame period or the non-display frame period, the single-pole double-throw switch S1 is electrically connected with the ADC1 module, the single-pole double-throw switch S1 is disconnected from the sensing line SL1, and the on-off states of the single-pole double-throw switch S2 of the sub-pixel driving circuit B and the single-pole double-throw switch S2 of the sub-pixel driving circuit C are synchronized with the on-off state of the single-pole double-throw switch S1 of the sub-pixel driving circuit a, which is not described herein again.
According to the pixel driving circuit, the invention further provides a display panel including the pixel driving circuit in the above embodiment. The display panel comprises pixel driving circuits distributed in an array mode, at least 3 adjacent columns of sub-pixel driving circuits of each pixel driving circuit are connected through sensing signal lines, and a charge absorption module is arranged at a signal input end of each sensing signal line.
The embodiment of the invention provides a pixel driving circuit and a display panel, wherein the pixel driving circuit comprises at least three sub-pixel driving circuits which are connected through an induction signal line, and a signal input end of the induction signal line is provided with a charge absorption module; the charge absorption module comprises a voltage comparison unit and a control unit which are connected; the voltage comparison unit comprises a reference signal input end, a comparison signal input end and a first output end; the control unit comprises a supply voltage input end, a control signal input end and a second output end; the second output end of the control unit is connected with the induction signal line and the comparison signal input end of the voltage comparison unit; and the first output end of the voltage comparison unit is connected with the control signal input end of the control unit. A comparison signal input end of the voltage comparison unit is used for acquiring the detection voltage of the induction signal line, and a reference signal input end of the voltage comparison unit is used for introducing reference voltage; when the detection voltage is greater than the reference voltage, the first output end of the voltage comparison unit outputs a low-voltage signal, the sensing signal line is grounded through the charge absorption module, the horizontal crosstalk charge of the sensing signal line is released until the reference voltage is equal to the detection voltage, and the supply voltage input end of the control unit outputs a reference voltage to the second output end of the control unit through the first thin film transistor, so that the voltage Vs of the drain electrode of the driving thin film transistor of each sub-pixel driving circuit is ensured to be stable, namely the initial voltage difference Vgs between the grid Vg and Vs of each driving thin film transistor is the same, the charging and discharging time of the storage capacitor Cst is the same, the display time in the display frame period is the same, and the display uniformity of each sub-pixel is ensured.
In summary, although the present invention has been described with reference to the preferred embodiments, the above-described preferred embodiments are not intended to limit the present invention, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, therefore, the scope of the present invention shall be determined by the appended claims.
Claims (10)
1. A pixel driving circuit is characterized by comprising at least three sub-pixel driving circuits, wherein the at least three sub-pixel driving circuits are connected through a sensing signal line, and a signal input end of the sensing signal line is provided with a charge absorption module;
the charge absorption module comprises a voltage comparison unit and a control unit which are connected;
the voltage comparison unit comprises a reference signal input end, a comparison signal input end and a first output end;
the control unit comprises a supply voltage input end, a control signal input end and a second output end; the second output end of the control unit is connected with the induction signal wire and the comparison signal input end of the voltage comparison unit; and the first output end of the voltage comparison unit is connected with the control signal input end of the control unit.
2. The pixel driving circuit according to claim 1, wherein the control unit comprises a first thin film transistor, a second thin film transistor, and a resistance module, the source electrode of the first thin film transistor is electrically connected with the power supply voltage input end of the control unit, the drain electrode of the first thin film transistor is electrically connected with the source electrode of the second thin film transistor, the drain electrode of the first thin film transistor and the source electrode of the second thin film transistor are both electrically connected with the second output end of the control unit, the drain electrode of the first thin film transistor is grounded through the resistance module, the grid electrode of the first thin film transistor is electrically connected with the grid electrode of the second thin film transistor, and the grid electrode of the first thin film transistor and the grid electrode of the second thin film transistor are both electrically connected with the control signal input end of the control unit.
3. The pixel driving circuit according to claim 2, wherein a comparison signal input terminal of the voltage comparing unit is configured to obtain a magnitude of the detection voltage of the sensing signal line, and a reference signal input terminal of the voltage comparing unit is configured to input a reference voltage;
when the detection voltage is greater than the reference voltage, a first output end of the voltage comparison unit outputs a low-voltage signal, the first thin film transistor is turned off, the second thin film transistor is turned on, the sensing signal line is grounded through a comparison signal input end of the voltage comparison unit, the second thin film transistor and the resistance module, and crosstalk charges fed back in the sub-pixel driving circuit are grounded until the detection voltage is equal to the reference voltage;
when the detection voltage is equal to the reference voltage, a first output end of the voltage comparison unit outputs a high-voltage signal, the second thin film transistor is closed, the first thin film transistor is conducted, and a supply voltage input end of the control unit outputs a reference voltage to a second output end of the control unit through the first thin film transistor.
4. The pixel driving circuit according to claim 2, wherein the first thin film transistor is an N-type thin film transistor, the second thin film transistor is a P-type thin film transistor, and the resistor module is one or more of a reactance, an inductor, and a resistor.
5. The pixel driving circuit according to claim 3, wherein the reference voltage is a constant voltage signal.
6. The pixel driving circuit according to claim 1, wherein the sub-pixel driving circuit is a 3T1C pixel circuit, and comprises a third thin film transistor, a fourth thin film transistor, a fifth thin film transistor, a storage capacitor Cst, and an OLED device, wherein a gate of the third thin film transistor is electrically connected to the first scan line, a source of the third thin film transistor is electrically connected to the data signal, and a drain of the third thin film transistor is electrically connected to the first node; the grid electrode of the fourth thin film transistor is electrically connected with the first node, the source electrode of the fourth thin film transistor is electrically connected with the positive voltage of the power supply, and the drain electrode of the fourth thin film transistor is electrically connected with the second node and the OLED device; a grid electrode of the fifth thin film transistor is electrically connected with the second scanning line, a source electrode of the fifth thin film transistor is electrically connected with the second node, and a drain electrode of the fifth thin film transistor is electrically connected with the second output end of the control unit through the induction signal line; a storage capacitor Cst is disposed between the first node and the second node.
7. The pixel driving circuit according to claim 6, wherein the sub-pixel driving circuit further comprises an ADC module and a single-pole double-throw switch, a drain of the fifth tft is electrically connected to a fixed end of the single-pole double-throw switch, the ADC module and the sensing signal line are respectively electrically connected to two movable ends of the single-pole double-throw switch, and the ADC module is configured to obtain a threshold voltage of the fourth tft.
8. The pixel driving circuit according to claim 7, wherein the single-pole double-throw switch is electrically connected to the sensing signal line and disconnected from the ADC module during a display time of a display frame period; and in the non-display time of the display frame period or the non-display frame period, the single-pole double-throw switch is electrically connected with the ADC module, and the single-pole double-throw switch is disconnected with the induction signal line.
9. The pixel driving circuit according to claim 8, wherein at least three horizontally arranged sub-pixel driving circuits are electrically connected to one of the charge draining modules through the same sensing signal line, and each of the sub-pixel driving circuits is separately provided with one of the ADC modules.
10. A display panel comprising the pixel drive circuit according to any one of claims 1 to 9.
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