CN111415620B - Pixel circuit, driving method thereof and display device - Google Patents
Pixel circuit, driving method thereof and display device Download PDFInfo
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- CN111415620B CN111415620B CN202010241068.4A CN202010241068A CN111415620B CN 111415620 B CN111415620 B CN 111415620B CN 202010241068 A CN202010241068 A CN 202010241068A CN 111415620 B CN111415620 B CN 111415620B
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- 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
- G09G3/3233—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 current through the light-emitting element
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Abstract
A pixel circuit for driving a light emitting element to emit light, comprising: a compensation sub-circuit, a control sub-circuit and a driving sub-circuit; the compensation sub-circuit is used for charging and discharging the first node under the control of the first scanning signal end, so that the voltage of the first node is equal to the sum of the data voltage provided by the data signal end and the threshold voltage of the driving sub-circuit; the control sub-circuit is used for conducting the first node and the second node under the control of the second scanning signal end and storing the voltage of the first node; a driving sub-circuit for supplying a driving current to the third node under the control of the second node; wherein the third node is coupled with the light emitting element.
Description
Technical Field
The present disclosure relates to but not limited to the field of display technologies, and in particular, to a pixel circuit, a driving method thereof, and a display device.
Background
In the display field, an Organic Light-Emitting Diode (OLED) has the characteristics of self-luminescence, high contrast, low energy consumption, wide viewing angle, high response speed, wide application range in flexible panels, wide application temperature range and the like, and has a wide development prospect. The OLED can be applied to devices with display functions, such as mobile phones, displays, notebook computers, digital cameras, instruments and meters. OLEDs are current driven and require a steady current to control the light emission. In general, the OLED display outputs a current to the OLED through a driving transistor in each pixel circuit to drive the OLED to emit light, wherein the driving current output by the driving transistor is related to its threshold voltage. However, the OLED has a drift phenomenon in the threshold voltage of the driving transistor after a long time use, and thus a display failure is easily caused.
Disclosure of Invention
The present disclosure provides a pixel circuit, a driving method thereof, and a display device, which can implement a threshold voltage compensation function in the pixel circuit.
In one aspect, the present disclosure provides a pixel circuit for driving a light emitting element to emit light, the pixel circuit including: a compensation sub-circuit, a control sub-circuit and a driving sub-circuit; the compensation sub-circuit is respectively coupled with the data signal terminal, the first node and the first scanning signal terminal, and is used for charging and discharging the first node under the control of the first scanning signal terminal, so that the voltage of the first node is equal to the sum of the data voltage provided by the data signal terminal and the threshold voltage of the driving sub-circuit; the control sub-circuit is respectively coupled with the first node, the second scanning signal terminal and the first power supply terminal, and is used for conducting the first node and the second node under the control of the second scanning signal terminal and storing the voltage of the first node; the driving sub-circuit is respectively coupled with the second node, the third node and a second power supply end and is used for providing driving current for the third node under the control of the second node; wherein the third node is coupled with a light emitting element.
In another aspect, the present disclosure provides a driving method of a pixel circuit, applied to the pixel circuit as described above, the driving method including: the compensation sub-circuit charges a first node under the control of a first scanning signal end; the compensation sub-circuit discharges the first node under the control of the first scanning signal end, so that the voltage of the first node is equal to the sum of the data voltage provided by the data signal end and the threshold voltage of the driving sub-circuit; the control sub-circuit is controlled by the second scanning signal end to conduct the first node and the second node and store the voltage of the first node, and the driving sub-circuit is controlled by the second node to provide driving current for the third node.
In another aspect, the present disclosure provides a display device including the pixel circuit as described above.
The pixel circuit provided by the disclosure realizes the threshold voltage compensation function by arranging the compensation sub-circuit, thereby improving the display effect.
Additional features and advantages of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the disclosure. Other advantages of the disclosure may be realized and attained by the instrumentalities and combinations particularly pointed out in the specification and the drawings.
Drawings
The accompanying drawings are included to provide an understanding of the disclosed embodiments and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the examples serve to explain the principles of the disclosure and not to limit the disclosure.
Fig. 1 is a schematic diagram of a pixel circuit according to at least one embodiment of the present disclosure;
fig. 2 is an equivalent circuit diagram of a compensation sub-circuit according to at least one embodiment of the present disclosure;
fig. 3 is an equivalent circuit diagram of a control sub-circuit according to at least one embodiment of the present disclosure;
fig. 4 is an equivalent circuit diagram of a driving sub-circuit according to at least one embodiment of the present disclosure;
fig. 5 is an equivalent circuit diagram of a pixel circuit according to at least one embodiment of the present disclosure;
fig. 6 is a timing diagram illustrating an operation of a pixel circuit according to at least one embodiment of the present disclosure;
fig. 7 is a flowchart of a driving method of a pixel circuit according to at least one embodiment of the present disclosure;
fig. 8 is an exemplary diagram of a display device according to at least one embodiment of the disclosure;
fig. 9 is a gate timing diagram of a gate line of a display device according to at least one embodiment of the present disclosure.
Detailed Description
The present disclosure describes embodiments, but the description is illustrative rather than limiting and it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the embodiments described in the present disclosure. Although many possible combinations of features are shown in the drawings and discussed in the embodiments, many other combinations of the disclosed features are possible. Any feature or element of any embodiment may be used in combination with or instead of any other feature or element in any other embodiment, unless expressly limited otherwise.
The present disclosure includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features and elements of the present disclosure that have been disclosed may also be combined with any conventional features or elements to form unique aspects as defined by the claims. Any feature or element of any embodiment may also be combined with features or elements from other aspects to form yet another unique aspect as defined by the claims. Thus, it should be understood that any features shown or discussed in this disclosure may be implemented separately or in any suitable combination. Accordingly, the embodiments are not limited except as by the appended claims and their equivalents. Furthermore, one or more modifications and changes may be made within the scope of the appended claims.
Further, in describing representative embodiments, the specification may have presented a method or process as a particular sequence of steps. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. Other orders of steps are possible as will be understood by those of ordinary skill in the art. Therefore, the particular order of the steps set forth in the specification should not be construed as limitations on the claims. Further, the claims directed to the method or process should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the sequences may be varied and still remain within the spirit and scope of the embodiments of the present disclosure.
In the drawings, the size of the constituent elements, the thickness of layers, or regions may be exaggerated for clarity. Therefore, one mode of the present disclosure is not necessarily limited to the dimensions, and the shape and size of each component in the drawings do not reflect a true scale. Further, the drawings schematically show ideal examples, and one embodiment of the present disclosure is not limited to the shapes, numerical values, and the like shown in the drawings.
Unless defined otherwise, technical or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The use of "first," "second," and similar terms in this disclosure is not intended to indicate any order, quantity, or importance, but rather is used to distinguish one element from another. In the present disclosure, "a plurality" may mean two or more numbers. The word "comprising" or "comprises", and the like, means that the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items. The terms "coupled," "connected," or "connected," and the like, are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "electrically connected" includes the case where constituent elements are connected together by an element having some sort of electrical action. The "element having a certain electric function" is not particularly limited as long as it can transmit and receive an electric signal between connected components. Examples of the "element having some kind of electric function" include not only an electrode and a wiring but also a switching element such as a transistor, a resistor, an inductor, a capacitor, another element having one or more functions, and the like.
To maintain the following description of the embodiments of the present disclosure clear and concise, a detailed description of some known functions and components have been omitted from the present disclosure. The drawings of the embodiments of the disclosure only relate to the structures related to the embodiments of the disclosure, and other structures can refer to the common design.
In the present disclosure, a transistor refers to an element including at least three terminals of a gate electrode, a drain electrode, and a source electrode. The transistor has a channel region between a drain electrode (drain electrode terminal, drain region, or drain electrode) and a source electrode (source electrode terminal, source region, or source electrode), and current can flow through the drain electrode, the channel region, and the source electrode. In the present disclosure, the channel region refers to a region through which current mainly flows. In the case of using transistors of opposite polarities, or in the case of changing the direction of current flow during circuit operation, the functions of the "source electrode" and the "drain electrode" may be interchanged. Therefore, in the present disclosure, "source electrode" and "drain electrode" may be interchanged with each other.
The transistors used in the embodiments of the present disclosure may be thin film transistors or field effect transistors or other devices with the same characteristics. Illustratively, the thin film transistor used in the embodiments of the present disclosure may be a low temperature polysilicon thin film transistor or an Oxide thin film transistor. Since the source and drain of the transistor used herein are symmetrical, the source and drain may be interchanged. In the embodiment of the present disclosure, in order to distinguish two electrodes of a transistor except for a gate, one of the electrodes is referred to as a first electrode, the other electrode is referred to as a second electrode, the first electrode may be a source or a drain, the second electrode may be a drain or a source, and the gate of the transistor is referred to as a control electrode. Also, the thin film transistor or the field effect transistor may be a P-type transistor, or may be an N-type transistor.
The embodiment of the disclosure provides a pixel circuit, a driving method thereof and a display device, which can realize the function of compensating the threshold voltage of a driving sub-circuit, thereby improving the display effect.
Fig. 1 is a schematic diagram of a pixel circuit according to at least one embodiment of the present disclosure. As shown in fig. 1, the present embodiment provides a pixel circuit for driving a light emitting element to emit light, including: a compensation sub-circuit, a control sub-circuit and a drive sub-circuit. The compensation sub-circuit is coupled to the data signal terminal DA, the first node P1 and the first scan signal terminal Gate1, and is configured to charge and discharge the first node P1 under the control of the first scan signal terminal Gate1, so that the voltage of the first node P1 is equal to the sum of the data voltage provided by the data signal terminal DA and the threshold voltage of the driving sub-circuit. And a control sub-circuit respectively coupled to the first node P1, the second node P2, the second scan signal terminal Gate2 and the first power source terminal Vss, for turning on the first node P1 and the second node P2 under the control of the second scan signal terminal Gate2 and storing the voltage of the first node P1. A driving sub-circuit respectively coupled to the second node P2, the third node P3 and the second power source terminal Vdd, for providing a driving current to the third node P3 under the control of the second node P2; the third node P3 is coupled to the light emitting device.
In the present embodiment, the first pole of the light emitting element is coupled to the third node P3, and the second pole of the light emitting element is coupled to the first power source terminal Vss. Illustratively, the light emitting element may be an OLED, the first pole being an anode and the second pole being a cathode.
The pixel circuit provided by the embodiment of the disclosure stores the threshold voltage of the driving sub-circuit through the compensation sub-circuit and compensates the threshold voltage to the data voltage, so that the threshold voltage compensation function is realized, and the display effect is improved.
In some examples, the voltage of the first power source terminal Vss may be continuously low, and the voltage of the second power source terminal Vdd may be continuously high.
In some examples, the second scan signal terminal Gate2 of the pixel circuit positioned at the nth row may be coupled to the nth Gate line corresponding to the row where the pixel circuit is positioned, and the first scan signal terminal Gate1 may be coupled to the (n-2) th Gate line corresponding to the pixel circuit positioned at the (n-2) th row. Wherein n is an integer greater than 2. The data signal terminal DA may be coupled to a data line corresponding to the pixel circuit. In this example, the first scan signal terminal Gate1 is coupled to the (n-2) th Gate line, and the threshold voltage compensation function of the driving sub-circuit can be realized without adding another signal source and slightly changing the design of the current display product.
Fig. 2 is an equivalent circuit diagram of a compensation sub-circuit according to at least one embodiment of the disclosure. As shown in fig. 2, the compensation sub-circuit includes: a first transistor M1, a second transistor M2, and a first capacitor C1. The control electrode and the first electrode of the first transistor M1 are coupled to the first node P1, and the second electrode of the first transistor M1 is coupled to the data signal terminal DA. A control electrode and a first electrode of the second transistor M2 are coupled to the first scan signal terminal Gate1, and a second electrode of the second transistor M2 is coupled to the first node P1. The first electrode of the first capacitor C1 is coupled to the first node P1, and the second electrode of the first capacitor C1 is coupled to the data signal terminal DA.
Fig. 2 shows an exemplary structure of the compensation sub-circuit, and those skilled in the art will readily understand that the implementation of the compensation sub-circuit is not limited thereto as long as the function thereof can be realized. The compensation sub-circuit provided by the exemplary embodiment has a simple structure, and reduces the design and process difficulty.
Fig. 3 is an equivalent circuit diagram of a control sub-circuit according to at least one embodiment of the disclosure. As shown in fig. 3, the control sub-circuit includes: a third transistor M3 and a second capacitor C2. A control electrode of the third transistor M3 is coupled to the second scan signal terminal Gate2, a first electrode of the third transistor M3 is coupled to the first node P1, and a second electrode of the third transistor M3 is coupled to the second node P2. A first electrode of the second capacitor C2 is coupled to the second node P2, and a second electrode of the second capacitor C2 is coupled to the first power supply terminal Vss.
Fig. 3 shows an exemplary structure of the control sub-circuit, and those skilled in the art will readily understand that the implementation of the control sub-circuit is not limited thereto as long as the function thereof can be realized.
Fig. 4 is an equivalent circuit diagram of a driving sub-circuit according to at least one embodiment of the present disclosure. As shown in fig. 4, the driving sub-circuit includes: the driving transistor M4, the control electrode of the driving transistor M4 is coupled to the second node P2, the first electrode of the driving transistor M4 is coupled to the second power source terminal Vdd, and the second electrode of the driving transistor M4 is coupled to the third node P3.
Fig. 4 shows an exemplary structure of the driving sub-circuit, and those skilled in the art will readily understand that the implementation of the driving sub-circuit is not limited thereto as long as the function thereof can be realized.
Fig. 5 is an equivalent circuit diagram of a pixel circuit according to at least one embodiment of the present disclosure. As shown in fig. 5, the pixel circuit for driving the light emitting element EL to emit light includes: a compensation sub-circuit, a control sub-circuit and a drive sub-circuit. The compensation sub-circuit comprises: a first transistor M1, a second transistor M2, and a first capacitor. The control sub-circuit includes: a third transistor M3 and a second capacitor C2. The driving sub-circuit includes: driving transistor M4.
In the present exemplary embodiment, a control electrode and a first electrode of the first transistor M1 are coupled to the first node P1, and a second electrode of the first transistor M1 is coupled to the data signal terminal DA. A control electrode and a first electrode of the second transistor M2 are coupled to the first scan signal terminal Gate1, and a second electrode of the second transistor M2 is coupled to the first node P1. The first electrode of the first capacitor C1 is coupled to the first node P1, and the second electrode of the first capacitor C1 is coupled to the data signal terminal DA. A control electrode of the third transistor M3 is coupled to the second scan signal terminal Gate2, a first electrode of the third transistor M3 is coupled to the first node P1, and a second electrode of the third transistor M3 is coupled to the second node P2. A first electrode of the second capacitor C2 is coupled to the second node P2, and a second electrode of the second capacitor C2 is coupled to the first power supply terminal Vss. The control electrode of the driving transistor M4 is coupled to the second node P2, the first electrode of the driving transistor M4 is coupled to the second power source terminal Vdd, and the second electrode of the driving transistor M4 is coupled to the third node P3. A first pole of the light emitting element EL is coupled to the third node P3, and a second pole of the light emitting element EL is coupled to the first power source terminal Vss.
In the exemplary embodiment, the transistors M1 to M3 and the driving transistor M4 may be N-type thin film transistors, which may unify the process flow, reduce the process steps, and help to improve the yield of the product. In addition, considering that the low temperature polysilicon thin film transistor has a small leakage current, the transistor of this embodiment may be a low temperature polysilicon thin film transistor, and the thin film transistor may be a thin film transistor with a bottom gate structure or a thin film transistor with a top gate structure, as long as the function can be achieved.
The following describes the technical solution of the present embodiment by an example of the working process of the pixel circuit.
Taking the transistors M1 to M3 and the driving transistor M4 in the pixel circuit provided by the present exemplary embodiment as examples, fig. 6 is an operation timing diagram of the pixel circuit provided by at least one embodiment of the present disclosure. As shown in fig. 5 and 6, the pixel circuit involved in the present exemplary embodiment includes: 3 switching transistors (M1 to M3), 1 driving transistor (M4), 2 capacitor cells (C1 and C2), 3 signal input terminals (DA, Gate1 and Gate2), 2 power supply terminals (Vdd and Vss). Wherein, the first power terminal Vss continuously provides a low level signal; the second power source terminal Vdd continuously supplies a high level signal.
As shown in fig. 6, in a Frame period, the pixel circuit of the present embodiment includes the following operating states: a charging phase T1, a discharging phase T2 and an operating phase T3.
In the charging period T1, the signal at the first scan signal terminal Gate1 is at a high level, and the signal at the second scan signal terminal Gate2 is at a low level.
The signal at the first scan signal terminal Gate1 is at a high level, the second transistor M2 is turned on, and the potential of the first node P1 is pulled up to the voltage provided by the first scan signal terminal Gate, which is denoted as Vgh, for example. The potential of the first node P1 is pulled high, the first transistor M1 is turned on, and the first capacitor C1 is charged, so that the voltage difference between the two ends of the first capacitor C1 is Vgh-Vdata, which is the voltage provided by the data signal end.
The signal of the second scan signal terminal Gate1 is at a low level, the third transistor M3 is turned off, the first node P1 and the second node P2 are turned off, and the driving transistor M4 is turned off.
In the discharging period T2, the signal at the first scan signal terminal Gate1 is at a low level, and the signal at the second scan signal terminal Gate2 is at a low level.
The signal at the first scan signal terminal Gate1 is at a low level, the second transistor M2 is turned off, and the first capacitor C1 discharges until the voltage difference between the two terminals of the first capacitor C1 is equal to the threshold voltage Vth1 of the first transistor M1.
The signal of the second scan signal terminal Gate2 is at a low level, the third transistor M3 is turned off, the first node P1 and the second node P2 are turned off, and the driving transistor M4 is turned off.
In the operation period T3, the signal at the first scan signal terminal Gate1 is at a low level, and the signal at the second scan signal terminal Gate2 is at a high level.
The signal of the first scan signal terminal Gate1 is at a low level, the second transistor M2 is turned off, and under the bootstrap action of the first capacitor C1, the potential of the first node P1 is Vdata + Vth1, where Vdata is the data voltage provided by the data signal terminal, and Vth1 is the threshold voltage of the first transistor M1. The threshold voltage Vth1 of the first transistor M1 is the same as the threshold voltage Vth2 of the driving transistor M4.
The signal of the second scan signal terminal Gate2 is at a high level, the third transistor M3 is turned on, thereby turning on the first node P1 and the second node P2, the second capacitor C2 can be charged, and the voltage of the first node P1 is stored by the second capacitor C2. The potential of the second node P2 is pulled high, and the driving transistor M4 is turned on.
During the operation period T3, the gate voltage of the driving transistor M4 is equal to the voltage of the second node P2, i.e., Vdata + Vth 1. The driving current I flowing through the light emitting element EL can be obtained from the current formula when the driving transistor M4 is saturatedOLEDSatisfies the following conditions:
IOLED＝K(Vgs–Vth2)2
＝K(Vdata+Vth1–Vth2)2
＝K(Vdata)2
where K is a fixed constant related to the process parameters and the geometry of the driving transistor M4; vgs is the gate-to-source voltage difference of the drive transistor M4; vth1 is the threshold voltage of the first transistor M1; vth2 is the threshold voltage of the drive transistor M4; vdata is the data voltage of the current frame.
Wherein,
μ is the channel mobility of the drive transistor, W and L are the channel width and length, respectively, of the drive transistor, CiIs the channel capacitance per unit area of the drive transistor.
As can be seen from the derivation result of the current formula, the threshold voltage of the first transistor M1 is the same as the threshold voltage of the driving transistor M4, so that, in the light emitting phase, the driving current output by the driving transistor M4 is not affected by the threshold voltage of the driving transistor M4, and is only related to the data voltage at the data signal terminal, thereby eliminating the influence of the threshold voltage of the driving transistor M4 on the driving current, further ensuring uniform display brightness, and improving the display effect.
In the exemplary embodiment, the compensation sub-circuit composed of two transistors and one capacitor is adopted to realize the storage and compensation functions of the threshold voltage of the driving transistor, the realization mode is simple, and the process burden is not required to be increased.
In the exemplary embodiment, the threshold voltage compensation function is realized by adopting the first transistor and the driving transistor with the same threshold voltage, so that the uniformity of the threshold voltage of the transistor of the pixel circuit can be improved, and the situation that the difference of the threshold voltage of the transistor of a large-size display product in different areas is large can be improved.
In some examples, the threshold voltage of the first transistor M1 and the threshold voltage of the driving transistor M4 may be similar, and the threshold voltage of the driving transistor M4 may also be compensated to some extent, so as to reduce the influence of the threshold voltage of the driving transistor M4 on the driving current.
In some examples, the second scan signal terminal of the pixel circuit located at the nth row may be coupled to the nth gate line corresponding to the row where the pixel circuit is located, and the first scan signal terminal may be coupled to the (n-2) th gate line corresponding to the pixel circuit located at the (n-2) th row. The second scanning signal end of the pixel circuit in the nth row may receive the nth Gate scanning signal Gate (n) output by the nth shift register unit of the Gate driving circuit to the nth Gate line, and the first scanning signal end may receive the nth-2 Gate scanning signal Gate (n-2) output by the nth-2 shift register unit of the Gate driving circuit to the nth-2 Gate line. In the exemplary embodiment, the pixel circuit does not need to add a new input signal line, and only the Gate scan signal Gate (n-2) on the (n-2) th Gate line is used as the charge-up start signal of the compensation sub-circuit. Therefore, the threshold voltage compensation function of the driving transistor can be realized by changing the current display product as little as possible without increasing the wire of a Gate Link Gate (PLG).
The embodiment of the disclosure also provides a driving method of the pixel circuit. Fig. 7 is a flowchart of a driving method of a pixel circuit according to at least one embodiment of the present disclosure. As shown in fig. 7, the driving method of the pixel circuit provided by the present exemplary embodiment includes the steps of:
The driving method of the pixel circuit provided by the present exemplary embodiment is applied to the pixel circuit provided by the foregoing embodiments, and the implementation principle and the effect are similar, so that the details are not repeated herein.
The embodiment of the disclosure also provides a display device, which includes the pixel circuit provided by the foregoing embodiment. The implementation principle and effect of the pixel circuit are similar to those of the foregoing embodiments, and therefore, the description thereof is omitted.
In some exemplary embodiments, a display device may include a display substrate, and a pixel circuit may be disposed on the display substrate. Illustratively, the display device may be: the OLED display panel comprises any product or component with a display function, such as an OLED panel, a mobile phone, a tablet computer, a television, a display, a notebook computer, a digital photo frame, a navigator and the like.
In some exemplary embodiments, the display device may include: the pixel circuit comprises a plurality of grid lines and a plurality of data lines which are arranged in a crossed mode, a grid driving circuit and a pixel circuit. The grid driving circuit is used for sequentially driving a plurality of grid lines; the first scanning signal end of the pixel circuit positioned on the nth row is coupled with the (n-2) th grid line corresponding to the pixel circuit positioned on the (n-2) th row, and the second scanning signal end of the pixel circuit positioned on the nth row is coupled with the nth grid line, wherein n is a positive integer greater than 2.
Fig. 8 is an exemplary diagram of a display device according to at least one embodiment of the present disclosure. As shown in fig. 8, the present exemplary embodiment provides a display device including: a plurality of gate lines and a plurality of data lines arranged in a crossing manner. The pixel circuit of each sub-pixel unit is coupled with one data line and two grid lines. The gate driving circuit may include a plurality of stages of shift register units, and each stage of shift register unit provides a gate scan signal to a corresponding gate line.
As shown in fig. 8, the first scan signal terminal Gate1 of the pixel circuit 11 of the (n-1) th row may be coupled to the (n-3) th Gate line to receive the (n-3) th Gate scan signal Gate (n-3) supplied from the (n-3) th stage shift register unit, and the second scan signal terminal Gate2 may be coupled to the (n-1) th Gate line to receive the (n-1) th Gate scan signal Gate (n-1) supplied from the (n-1) th stage shift register unit. The first scan signal terminal Gate1 of the pixel circuit 12 in the nth row may be coupled to the (n-2) th Gate line to receive the (n-2) th Gate scan signal Gate (n-2) provided by the (n-2) th stage shift register unit, and the second scan signal terminal Gate2 may be coupled to the nth Gate line to receive the (n) th Gate scan signal Gate (n) provided by the (n) th stage shift register unit. The first scan signal terminal Gate1 of the pixel circuit 13 of the (n +1) th row may be coupled to the (n-1) th Gate line to receive the (n-1) th Gate scan signal Gate (n-1) provided from the (n-1) th shift register unit, and the second scan signal terminal Gate2 may be coupled to the (n +1) th Gate line to receive the (n +1) th Gate scan signal Gate (n +1) provided from the (n +1) th shift register unit.
Fig. 9 is a gate timing diagram of a gate line of a display device according to at least one embodiment of the present disclosure. Taking the pixel circuit in the nth row in fig. 8 as an example, the first scan signal terminal Gate1 receives the Gate scan signal Gate (n-2), and the second scan signal terminal Gate2 receives the Gate scan signal Gate (n). As shown in fig. 6 and 9, the Gate scan signal Gate (n-2) may serve as a charge-on signal to the compensation sub-circuit of the pixel circuit of the nth row. In the exemplary embodiment, PLG wiring does not need to be added, and the threshold voltage compensation function of the driving transistor can be realized by changing the current display product as little as possible.
The drawings of the embodiments of the present disclosure relate only to the structures to which the embodiments of the present disclosure relate, and other structures may refer to general designs.
Although the embodiments disclosed in the present disclosure are described above, the descriptions are only for the convenience of understanding the present disclosure, and are not intended to limit the present disclosure. It will be understood by those skilled in the art of the present disclosure that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure, and that the scope of the disclosure is to be limited only by the terms of the appended claims.
Claims (10)
1. A pixel circuit for driving a light emitting element to emit light, the pixel circuit comprising: a compensation sub-circuit, a control sub-circuit and a driving sub-circuit;
the compensation sub-circuit is respectively coupled with the data signal terminal, the first node and the first scanning signal terminal, and is used for charging and discharging the first node under the control of the first scanning signal terminal, so that the voltage of the first node is equal to the sum of the data voltage provided by the data signal terminal and the threshold voltage of the driving sub-circuit;
the control sub-circuit is respectively coupled with the first node, the second scanning signal terminal and the first power supply terminal, and is used for conducting the first node and the second node under the control of the second scanning signal terminal and storing the voltage of the first node;
the driving sub-circuit is respectively coupled with the second node, the third node and a second power supply end and is used for providing driving current for the third node under the control of the second node; wherein the third node is coupled with a light emitting element.
2. The pixel circuit according to claim 1, wherein the second scan signal terminal of the pixel circuit in the nth row is coupled to the nth gate line corresponding to the row of the pixel circuit, and the first scan signal terminal is coupled to the (n-2) th gate line corresponding to the pixel circuit in the (n-2) th row, where n is an integer greater than 2.
3. The pixel circuit of claim 1, wherein the compensation sub-circuit comprises: a first transistor, a second transistor, and a first capacitor;
a control electrode and a first electrode of the first transistor are coupled with a first node, and a second electrode of the first transistor is coupled with a data signal terminal;
a control electrode and a first electrode of the second transistor are coupled with a first scanning signal end, and a second electrode of the second transistor is coupled with a first node;
the first electrode of the first capacitor is coupled to the first node, and the second electrode of the first capacitor is coupled to the data signal terminal.
4. The pixel circuit of claim 1, wherein the control sub-circuit comprises: a third transistor and a second capacitor;
a control electrode of the third transistor is coupled to the second scan signal terminal, a first electrode of the third transistor is coupled to the first node, and a second electrode of the third transistor is coupled to the second node;
the first electrode of the second capacitor is coupled to the second node, and the second electrode of the second capacitor is coupled to the first power supply terminal.
5. The pixel circuit of claim 1, wherein the drive sub-circuit comprises: and a control electrode of the driving transistor is coupled with the second node, a first electrode of the driving transistor is coupled with a second power supply end, and a second electrode of the driving transistor is coupled with the third node.
6. The pixel circuit of claim 1, wherein the compensation sub-circuit comprises: a first transistor, a second transistor, and a first capacitor; a control electrode and a first electrode of the first transistor are coupled with a first node, and a second electrode of the first transistor is coupled with a data signal terminal; a control electrode and a first electrode of the second transistor are coupled with a first scanning signal end, and a second electrode of the second transistor is coupled with a first node; a first electrode of the first capacitor is coupled with a first node, and a second electrode of the first capacitor is coupled with a data signal terminal;
the control sub-circuit includes: a third transistor and a second capacitor; a control electrode of the third transistor is coupled to the second scan signal terminal, a first electrode of the third transistor is coupled to the first node, and a second electrode of the third transistor is coupled to the second node; a first electrode of the second capacitor is coupled to a second node, and a second electrode of the second capacitor is coupled to a first power supply terminal;
the driving sub-circuit includes: and a control electrode of the driving transistor is coupled with the second node, a first electrode of the driving transistor is coupled with a second power supply end, and a second electrode of the driving transistor is coupled with the third node.
7. The pixel circuit according to claim 6, wherein a threshold voltage of the first transistor is the same as a threshold voltage of the driving transistor.
8. A driving method of a pixel circuit, applied to the pixel circuit according to any one of claims 1 to 7, the driving method comprising:
the compensation sub-circuit charges a first node under the control of a first scanning signal end;
the compensation sub-circuit discharges the first node under the control of the first scanning signal end, so that the voltage of the first node is equal to the sum of the data voltage provided by the data signal end and the threshold voltage of the driving sub-circuit;
the control sub-circuit is controlled by the second scanning signal end to conduct the first node and the second node and store the voltage of the first node, and the driving sub-circuit is controlled by the second node to provide driving current for the third node.
9. A display device, comprising: a pixel circuit as claimed in any one of claims 1 to 7.
10. The display device according to claim 9, further comprising: a plurality of grid lines and a plurality of data lines which are arranged in a crossed manner, and a grid driving circuit; the grid driving circuit is used for sequentially driving the grid lines; the first scanning signal end of the pixel circuit positioned on the nth row is coupled with the (n-2) th grid line corresponding to the pixel circuit positioned on the (n-2) th row, and the second scanning signal end of the pixel circuit positioned on the nth row is coupled with the nth grid line, wherein n is a positive integer greater than 2.
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| CN113299235B (en) * | 2021-05-20 | 2022-10-25 | 京东方科技集团股份有限公司 | Pixel circuit, driving method thereof and display device |
| CN114267313B (en) * | 2021-12-30 | 2023-01-13 | 惠科股份有限公司 | Driving circuit and driving method, gate driving circuit and display device |
| CN114283744A (en) | 2021-12-30 | 2022-04-05 | 重庆惠科金渝光电科技有限公司 | Driving method of display unit, display panel and display device |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7218296B2 (en) * | 2004-03-18 | 2007-05-15 | Wintek Corporation | Active matrix organic electroluminescence light emitting diode driving circuit |
| CN101251982A (en) * | 2008-04-07 | 2008-08-27 | 上海广电光电子有限公司 | Pixel circuit for improving active matrix organic light-emitting device life period |
| CN103000131A (en) * | 2012-12-05 | 2013-03-27 | 京东方科技集团股份有限公司 | Pixel circuit and drive method, display panel and display device thereof |
| CN103021328A (en) * | 2012-11-23 | 2013-04-03 | 京东方科技集团股份有限公司 | Pixel circuit for driving light emitting device to emit light and display device |
| CN103839520A (en) * | 2014-02-28 | 2014-06-04 | 京东方科技集团股份有限公司 | Pixel circuit, method for driving pixel circuit, display panel and display device |
| CN106782327A (en) * | 2017-04-14 | 2017-05-31 | 京东方科技集团股份有限公司 | Image element circuit and its driving method, array base palte, display panel and display device |
| CN108154834A (en) * | 2018-03-15 | 2018-06-12 | 京东方科技集团股份有限公司 | The cross-pressure detection method of electroluminescence display panel and luminescent device |
| CN108766361A (en) * | 2018-05-31 | 2018-11-06 | 京东方科技集团股份有限公司 | Pixel circuit and its driving method, display device |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20140140272A (en) * | 2013-05-29 | 2014-12-09 | 삼성디스플레이 주식회사 | Pixel and Organic Light Emitting Display Device Using the same |
| CN105206222B (en) * | 2014-06-20 | 2018-06-19 | 上海和辉光电有限公司 | Oled pixel compensation circuit and oled pixel driving method |
| CN104637445B (en) * | 2015-02-03 | 2017-03-08 | 深圳市华星光电技术有限公司 | AMOLED pixel-driving circuit and image element driving method |
| CN107871471B (en) * | 2017-12-08 | 2020-04-10 | 京东方科技集团股份有限公司 | Pixel driving circuit, driving method thereof and display device |
| CN108597444B (en) * | 2018-04-19 | 2020-08-14 | 东南大学 | A silicon-based OLED pixel circuit and a method for compensating for changes in OLED electrical characteristics |
-
2020
- 2020-03-31 CN CN202010241068.4A patent/CN111415620B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7218296B2 (en) * | 2004-03-18 | 2007-05-15 | Wintek Corporation | Active matrix organic electroluminescence light emitting diode driving circuit |
| CN101251982A (en) * | 2008-04-07 | 2008-08-27 | 上海广电光电子有限公司 | Pixel circuit for improving active matrix organic light-emitting device life period |
| CN103021328A (en) * | 2012-11-23 | 2013-04-03 | 京东方科技集团股份有限公司 | Pixel circuit for driving light emitting device to emit light and display device |
| CN103000131A (en) * | 2012-12-05 | 2013-03-27 | 京东方科技集团股份有限公司 | Pixel circuit and drive method, display panel and display device thereof |
| CN103839520A (en) * | 2014-02-28 | 2014-06-04 | 京东方科技集团股份有限公司 | Pixel circuit, method for driving pixel circuit, display panel and display device |
| CN106782327A (en) * | 2017-04-14 | 2017-05-31 | 京东方科技集团股份有限公司 | Image element circuit and its driving method, array base palte, display panel and display device |
| CN108154834A (en) * | 2018-03-15 | 2018-06-12 | 京东方科技集团股份有限公司 | The cross-pressure detection method of electroluminescence display panel and luminescent device |
| CN108766361A (en) * | 2018-05-31 | 2018-11-06 | 京东方科技集团股份有限公司 | Pixel circuit and its driving method, display device |
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|---|---|
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