CN109754756B - Pixel circuit, driving method thereof, display substrate and display device - Google Patents
Pixel circuit, driving method thereof, display substrate and display device Download PDFInfo
- Publication number
- CN109754756B CN109754756B CN201910239895.7A CN201910239895A CN109754756B CN 109754756 B CN109754756 B CN 109754756B CN 201910239895 A CN201910239895 A CN 201910239895A CN 109754756 B CN109754756 B CN 109754756B
- Authority
- CN
- China
- Prior art keywords
- driving
- circuit
- node
- voltage
- coupled
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Control Of El Displays (AREA)
- Electroluminescent Light Sources (AREA)
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
Abstract
The invention discloses a pixel circuit, a driving method thereof, a display substrate and a display device. The pixel circuit includes a voltage driving circuit and a current control circuit. Because this current control circuit can be according to the drive voltage of voltage drive circuit output to first node, to luminous element output first drive current, and because be linear relation between luminous luminance and the electric current of luminous element, be linear relation between electric current and the voltage, consequently can be so that be linear relation between luminous luminance and the drive voltage of luminous element, and then be convenient for more adjust luminous luminance of luminous element, the drive flexibility is higher.
Description
Technical Field
The invention relates to the technical field of display, in particular to a pixel circuit, a driving method thereof, a display substrate and a display device.
Background
Organic Light Emitting Diodes (OLEDs) are widely used in high performance display panels due to their advantages of being light and thin, self-emitting, high in contrast, and wide in operating temperature range. For example, OLED devices are currently used in the more rapidly developing microdisplays.
In the related art, the OLED display panel may include a plurality of pixel units arranged in an array, and each of the pixel units may include a switching transistor, a driving transistor, and a light emitting element to which a source of the driving transistor is connected. The switching transistor can output the data voltage provided by the data signal end to the grid electrode of the driving transistor, and the source electrode voltage of the driving transistor can change along with the grid electrode voltage of the driving transistor, so that a potential difference is formed at two ends of the light-emitting element, and the light-emitting element is driven to emit light.
However, since the luminance of the light emitting device and the source voltage have a nonlinear relationship, it is inconvenient to adjust the luminance of the light emitting device, and the driving flexibility is poor.
Disclosure of Invention
The invention provides a pixel circuit, a driving method thereof, a display substrate and a display device, which can solve the problems that the brightness of a light-emitting element is not convenient to adjust and the driving flexibility is poor in the related technology. The technical scheme is as follows:
in one aspect, a pixel circuit is provided, the pixel circuit including: a voltage driving circuit and a current control circuit;
the voltage driving circuit is coupled to a gate signal terminal, a data signal terminal, a light emission control signal terminal, and a first node, respectively, and is configured to output a driving voltage to the first node in response to a gate driving signal from the gate signal terminal, a light emission control signal from the light emission control signal terminal, and a data signal from the data signal terminal;
the current control circuit is coupled to the first node and the light emitting element, and is configured to output a first driving current to the light emitting element according to the driving voltage.
Optionally, the current control circuit includes: a current control sub-circuit and a current mirror circuit;
the current control sub-circuit is respectively coupled with the first node and the second node, and is used for outputting a second driving current to the second node according to the driving voltage;
the current mirror circuit is coupled to the second node and the light emitting element, respectively, and the current mirror circuit is configured to output the first driving current to the light emitting element according to the second driving current.
Optionally, the current control sub-circuit includes: a first resistor;
one end of the first resistor is coupled to the first node, and the other end of the first resistor is coupled to the second node.
Optionally, the resistance value of the first resistor is greater than a resistance threshold value;
the resistance threshold value R satisfies:
vmin is a product of an upper limit of a gray-scale value which can be displayed by the pixel unit and a data voltage adjusting step length of the data signal, Rgs is a gate-source resistance value of a driving transistor in the voltage driving circuit, Vd is an upper limit voltage of the data signal, and Vth is a threshold voltage of the driving transistor.
Optionally, the current mirror circuit includes: an input transistor and an output transistor;
a gate and a first pole of the input transistor are both coupled to the second node, and a second pole of the input transistor is coupled to a first power supply terminal;
a gate of the output transistor is coupled to the second node, a first pole of the output transistor is coupled to the first power supply terminal, and a second pole of the output transistor is coupled to the light emitting element.
Optionally, the ratio of the width-to-length ratio of the output transistor to the input transistor is greater than 1.
Optionally, the voltage driving circuit includes: a data writing sub-circuit, a light emission control sub-circuit, a storage sub-circuit, and a driving sub-circuit;
the data writing sub-circuit is respectively coupled with the gate signal terminal, the data signal terminal and a third node, and is used for responding to the gate driving signal and outputting the data signal to the third node;
the light-emitting control sub-circuit is respectively coupled with the light-emitting control signal terminal, the second power terminal and the fourth node, and is configured to output a second power signal provided by the second power terminal to the fourth node in response to the light-emitting control signal;
the storage sub-circuit is coupled to the third node, the storage sub-circuit being configured to control a voltage of the third node;
the driving sub-circuit is respectively coupled with the third node, the fourth node and the first node, and is used for outputting a driving voltage to the first node under the driving of the third node and the fourth node.
In another aspect, there is provided a driving method of a pixel circuit, applied to the pixel circuit according to the above aspect, the method including:
the gate signal terminal provides a gate driving signal, the light emission control signal terminal provides a light emission control signal, the data signal terminal provides a data signal, the voltage driving circuit outputs a driving voltage to the first node in response to the gate driving signal, the light emission control signal and the data signal, and the current control circuit outputs a first driving current to the light emitting element according to the driving voltage.
In yet another aspect, a display substrate is provided, the display substrate including: a plurality of pixel cells, at least one of the pixel cells comprising: a light emitting element, and a pixel circuit as described in the above aspect coupled to the light emitting element.
In still another aspect, there is provided a display device including: a display substrate as described in the preceding aspect.
The technical scheme provided by the invention has the beneficial effects that at least:
the embodiment of the invention provides a pixel circuit, a driving method thereof, a display substrate and a display device. The pixel circuit includes a voltage driving circuit and a current control circuit. Because this current control circuit can be according to the drive voltage of voltage drive circuit output to first node, to luminous element output first drive current, and because be linear relation between luminous luminance and the electric current of luminous element, be linear relation between electric current and the voltage, consequently can be so that be linear relation between luminous luminance and the drive voltage of luminous element, and then be convenient for more adjust luminous luminance of luminous element, the drive flexibility is higher.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a pixel circuit according to an embodiment of the present invention;
FIG. 2 is a diagram illustrating a variation of luminance with data voltage according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of another pixel circuit according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of another pixel circuit according to an embodiment of the present invention;
FIG. 5 is a diagram illustrating a variation of luminance of a light emitting device with a data voltage of a data signal at different aspect ratio ratios according to an embodiment of the present invention;
FIG. 6 is a schematic structural diagram of a pixel circuit according to yet another embodiment of the present invention;
FIG. 7 is a schematic structural diagram of a pixel circuit according to yet another embodiment of the present invention;
fig. 8 is a timing diagram of each signal terminal of a pixel circuit according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
The transistors used in all embodiments of the present invention may be thin film transistors or field effect transistors or other devices having the same characteristics, and the transistors used in embodiments of the present invention are mainly switching transistors depending on the role in the circuit. Since the source and drain of the switching transistor used herein are symmetrical, the source and drain may be interchanged. In the embodiment of the present invention, the source is referred to as a first pole and the drain is referred to as a second pole, or the drain may be referred to as a first pole and the source may be referred to as a second pole. The form of the figure provides that the middle end of the transistor is a grid, the signal input end is a source, and the signal output end is a drain. The switch transistor used in the embodiment of the invention can be a P-type switch transistor, and the P-type switch transistor is turned on when the grid electrode is at a low level and is turned off when the grid electrode is at a high level. In addition, the plurality of signals in the embodiments of the present invention correspond to the first potential and the second potential. The first potential and the second potential represent only 2 state quantities of the potential of the signal, and do not represent that the first potential or the second potential has a specific value throughout the text. In the embodiment of the present invention, the first potential is taken as an example of the effective potential.
Currently, the light emitting elements included in the OLED display panel may be driven to emit light by a voltage driving method (i.e., a source follower method). In the source follower mode, the source voltage of the drive transistor may change following the gate voltage of the drive transistor. Accordingly, the two ends of the light emitting element can be pressed to drive the light emitting element to emit light.
However, since the light-emitting luminance of the light-emitting element has a nonlinear relationship with the voltage, when the light-emitting element is directly driven by the source voltage, the light-emitting luminance of the light-emitting element has a nonlinear relationship with the source voltage. Since the gate voltage of the driving transistor is the data voltage of the data signal output from the data signal terminal, the light emitting luminance of the light emitting element has a nonlinear relationship with the data voltage. Correspondingly, the brightness of the light emitting element is inconvenient to adjust by adjusting the data voltage, and the driving flexibility is poor.
An embodiment of the present invention provides a pixel circuit, which can solve the problems of inconvenient adjustment of the brightness of a light emitting element and poor driving flexibility in the related art, and fig. 1 is a schematic structural diagram of a pixel circuit according to an embodiment of the present invention. As shown in fig. 1, the pixel circuit may include: a voltage driving circuit 10 and a current control circuit 20.
The voltage driving circuit 10 may be coupled to the gate signal terminal G1, the data signal terminal D1, the emission control signal terminal EM1, and the first node P1, respectively. The voltage driving circuit 10 may output a driving voltage to the first node P1 in response to a gate driving signal from a gate signal terminal G1, a light emission control signal from a light emission control signal terminal EM1, and a data signal from a data signal terminal D1.
Wherein the coupling may comprise: the two ends are electrically connected or the two ends are directly connected (for example, the two ends are connected through a signal wire). The embodiment of the present invention does not limit the coupling manner between the two ends.
For example, the voltage driving circuit 10 may store the data voltage of the data signal provided from the data signal terminal D1 according to the gate driving signal provided from the gate signal terminal G1. And may output a driving voltage to the first node P1 based on the stored data voltage, driven by a light emission control signal supplied from the light emission control signal terminal EM 1. Also, the driving voltage may vary following the data voltage of the data signal.
The current control circuit 20 can be coupled to the first node P1 and the light emitting element O1, respectively. The current control circuit 20 can output a first drive current to the light emitting element O1 in accordance with the drive voltage.
For example, the current control circuit 20 may generate a constant first driving current (i.e., a constant current) according to the driving voltage output from the voltage driving circuit 10 to the first node P1, and output the first driving current to the light emitting element O1, thereby driving the light emitting element O1 to emit light.
Since the light-emitting luminance of the light-emitting device O1 has a linear relationship with the current and the current has a linear relationship with the voltage, the current control circuit 20 outputs the first driving current to the light-emitting device O1 according to the driving voltage, so that the light-emitting luminance of the light-emitting device O1 has a linear relationship with the driving voltage. In addition, since the driving voltage can change along with the data voltage of the data signal, a linear relationship can be formed between the light-emitting brightness of the light-emitting element O1 and the data voltage, so that the light-emitting brightness of the light-emitting element O1 can be conveniently adjusted by adjusting the data voltage of the data signal, and the driving flexibility is better.
Illustratively, fig. 2 is a schematic diagram illustrating a variation of the light-emitting luminance B with the data voltage Vd according to an embodiment of the present invention. Referring to fig. 2, it can be seen that in the pixel circuit provided by the embodiment of the invention, the data voltage Vd has a linear relationship with the light emitting luminance B of the light emitting element O1. In the pixel circuit provided in the related art, the data voltage Vd and the light emission luminance B of the light emitting element O1 have a nonlinear relationship.
In summary, embodiments of the present invention provide a pixel circuit, which includes a current control circuit. Because this current control circuit can be according to the drive voltage of voltage drive circuit output to first node, to luminous element output first drive current, and because be linear relation between luminous luminance and the electric current of luminous element, be linear relation between electric current and the voltage, consequently can be so that be linear relation between luminous luminance and the drive voltage of luminous element, and then be convenient for more adjust luminous luminance of luminous element, the drive flexibility is higher.
Fig. 3 is a schematic structural diagram of another pixel circuit according to an embodiment of the present invention. As shown in fig. 3, the current control circuit 20 may include: a current control sub-circuit 201 and a current mirror circuit 202.
The current control sub-circuit 201 may be coupled to a first node P1 and a second node P2, respectively. The current control sub-circuit 201 may output a second driving current to the second node P2 according to the driving voltage.
For example, the current control sub-circuit 201 may convert the driving voltage of the first node P1 into the second driving current, and output the second driving current to the second node P2.
The current mirror circuit 202 may be coupled to the second node P2 and the light emitting element O1, respectively. The current mirror circuit 202 can output the first drive current to the light emitting element O1 in accordance with the second drive current.
For example, the current mirror circuit 202 may generate the first driving current from the second driving current and output the first driving current to the light emitting element O1. And the first driving current is a constant current, that is, the first driving current is not affected by the internal resistance of the light emitting element O1.
Fig. 4 is a schematic structural diagram of another pixel circuit according to an embodiment of the present invention. As shown in fig. 4, the current control sub-circuit 201 may include: a first resistor R1.
One end of the first resistor R1 may be coupled to a first node P1, and the other end of the first resistor R1 may be coupled to a second node P2.
In an embodiment of the present invention, the resistance of the first resistor R1 may be greater than a resistance threshold. The resistance threshold R may satisfy:
vmin is the product of the upper limit of the gray-scale value that can be displayed by the pixel unit and the data voltage adjustment step length of the data signal, Rgs is the gate-source resistance value of the driving transistor in the voltage driving circuit 10, Vd is the upper limit voltage of the data signal, and Vth is the threshold voltage of the driving transistor.
For example, assuming that the number of gray scale bits of an OLED display panel is 8 bits (bits), the upper limit of the gray scale value that each pixel unit included in the OLED display panel can display is 255, assuming that the data voltage adjustment step of the data signal is 20 millivolts (mv), that is, when the source driving circuit adjusts the data voltage of the data signal, the minimum adjustment range is 20 mv., Vmin is 20mv × 255V 5.1 volts (V), Rgs is 109Ohm (omega), Vd 6V, Vth 0.7V, then substituting the parameters into the formula (1) to obtain the resistance value threshold R of 2.55 × 1010Correspondingly, the resistance value of the first resistor R1 is satisfied, R is more than 2.55 × 1010Ω。
Alternatively, referring to fig. 4, the current mirror circuit 202 may include: an input transistor M1 and an output transistor M2.
The gate and the first pole of the input transistor M1 may be both coupled to the second node P2, and the second pole of the input transistor M1 may be coupled to the first power supply terminal VSS.
The gate of the output transistor M2 may be coupled to the second node P2, the first pole of the output transistor M2 may be coupled to the first power source terminal VSS, and the second pole of the output transistor M2 may be coupled to the light emitting element O1. In addition, as can be seen with reference to fig. 4, the light emitting element O1 may also be connected to the second power supply terminal VDD.
Alternatively, the ratio of the width-to-length ratio of the output transistor M2 to the input transistor M1 may be greater than 1.
Due to the ratio of the first driving current and the second driving current, it may be equal to the ratio of the width-to-length ratios of the output transistor M2 and the input transistor M1. That is, the first driving current may be equal to the product of the ratio of the width-to-length ratios of the output transistor M2 and the input transistor M1 and the second driving current. Therefore, by setting the ratio of the width-to-length ratio of the output transistor M2 to the input transistor M1 to a number greater than 1, a current amplification function can be realized, the light emission luminance of the light emitting element O1 is further improved, and the display effect is better.
Correspondingly, the ratio of the first driving current to the second driving current output to the light-emitting element O1 can be adjusted by adjusting the width-to-length ratio of at least one of the output transistor M2 and the input transistor M1, so as to adjust the light-emitting brightness of the light-emitting element O1, and the driving flexibility is higher.
For example, it is assumed that the width-to-length ratio of the output transistor M2 is W2/L2, the width-to-length ratio of the input transistor M1 is W1/L1, and the ratio of the width-to-length ratios of the output transistor M2 and the input transistor M1 is 2, that is, W2/L2 is 2 (W1/L1). The ratio of the first driving current to the second driving current is 2, that is, the current mirror circuit 202 may amplify the second driving current by 2 times and output the amplified second driving current to the light emitting element O1.
Fig. 5 is a schematic diagram illustrating that the luminance B of the light emitting device varies with the data voltage Vd of the data signal under different aspect ratio ratios according to the embodiment of the present invention. As shown in fig. 5, when the data voltages of the data signals provided by the data signal terminal D1 are all Vd1, if the ratio of the width-to-length ratios of the output transistor M2 and the input transistor M1 is 2, that is, the ratio of the width-to-length ratios satisfies: when W2/L2 is 2(W1/L1), the light-emitting luminance of the light-emitting element O1 is B2. If the ratio of the width-to-length ratios of the output transistor M2 and the input transistor M1 is 1, that is, the ratio of the width-to-length ratios satisfies: when W2/L2 is W1/L1, the light-emitting luminance of the light-emitting element O1 is B1. Referring to fig. 5, it can be seen that B2 is 2 times that of B1.
It should be noted that the current mirror circuit 202 may have a structure including other number of transistors, such as a 1T structure or a 4T structure, besides the 2T (i.e., 2 transistors) structure shown in fig. 4, which is not limited in this embodiment of the present invention.
Fig. 6 is a schematic structural diagram of another pixel circuit according to an embodiment of the present invention. As shown in fig. 6, the voltage driving circuit 10 may include: a data writing sub-circuit 101, a light emission control sub-circuit 102, a memory sub-circuit 103, and a driving sub-circuit 104.
The data writing sub-circuit 101 may be coupled to the gate signal terminal G1, the data signal terminal D1, and the third node P3, respectively. The data writing sub-circuit 101 may output a data signal to the third node P3 in response to a gate driving signal.
For example, the data writing sub-circuit 101 may output the data signal to the third node P3 when the potential of the gate driving signal is the first potential.
The light-emission control sub-circuit 102 may be coupled to the light-emission control signal terminal EM1, the second power source terminal VDD, and the fourth node P4, respectively. The light-emission control sub-circuit 102 may output the second power signal supplied from the second power terminal VDD to the fourth node P4 in response to the light-emission control signal.
For example, the light emission control sub-circuit 102 may output the second power supply signal supplied from the second power supply terminal VDD to the fourth node P4 when the potential of the light emission control signal is the first potential. The potential of the second power signal may be the first potential.
The memory sub-circuit 103 may be coupled to a third node P3. The storage sub-circuit 103 may control the voltage of the third node P3. For example, the storage sub-circuit 103 may store the potential of the third node P3.
The driving sub-circuit 104 may be coupled to the third node P3, the fourth node P4, and the first node P1, respectively. The driving sub-circuit 104 may output a driving voltage to the first node P1 under the driving of the third node P3 and the fourth node P4.
For example, the driving sub-circuit 104 may output a driving voltage to the first node P1 according to the potential of the third node P3 and the potential of the fourth node P4.
Fig. 7 is a schematic structural diagram of another pixel circuit according to an embodiment of the present invention. Referring to fig. 7, the gate signal terminal G1 may include a first gate signal terminal G11 and a second gate signal terminal G12. Accordingly, the data writing sub-circuit 101 may include: a first switching transistor K1 and a second switching transistor K2. The emission control sub-circuit 102 may include: the light emission controlling transistor T1. The memory sub-circuit 103 may include: a storage capacitor C1. The driving sub-circuit 104 may include: driving the transistor T1.
A gate of the first switching transistor K1 may be coupled to the first gate signal terminal G1, a first pole of the first switching transistor K1 may be coupled to the data signal terminal D1, and a second pole of the first switching transistor K1 may be coupled to the third node P3.
A gate of the second switching transistor K2 may be coupled to the second gate signal terminal G1, a second pole of the second switching transistor K2 may be coupled to the data signal terminal D1, and a second pole of the second switching transistor K2 may be coupled to the third node P3.
A gate of the light-emission controlling transistor L1 may be coupled to the light-emission control signal terminal EM1, a second pole of the light-emission controlling transistor L1 may be coupled to the second power source terminal VDD, and a second pole of the light-emission controlling transistor L1 may be coupled to the fourth node P4.
One terminal of the storage capacitor C1 may be coupled to the third node P3, and the other terminal of the storage capacitor C1 may be coupled to the first power source terminal VSS.
The gate of the driving transistor T1 may be coupled to the third node P3, the first pole of the driving transistor T1 may be coupled to the fourth node P4, and the second pole of the driving transistor T1 may be coupled to the first node P1.
It should be noted that, in the embodiment of the present invention, the voltage driving circuit 10 may have a structure including other number of transistors, such as a 2T1C structure or a 6T1C structure, in addition to the structure of 4T1C (i.e., four transistors and one capacitor) shown in fig. 7, which is not limited in the embodiment of the present invention.
In summary, embodiments of the present invention provide a pixel circuit, which includes a current control circuit. Because this current control circuit can be according to the drive voltage of voltage drive circuit output to first node, to luminous element output first drive current, and because be linear relation between luminous luminance and the electric current of luminous element, be linear relation between electric current and the voltage, consequently can be so that be linear relation between luminous luminance and the drive voltage of luminous element, and then be convenient for more adjust luminous luminance of luminous element, the drive flexibility is higher.
Embodiments of the present invention provide a driving method for a pixel circuit, which may be applied to the pixel circuit shown in any one of fig. 1, fig. 3, fig. 4, fig. 6, and fig. 7. The method can comprise the following steps:
the gate signal terminal provides a gate driving signal, the light emission control signal terminal provides a light emission control signal, the data signal terminal provides a data signal, the voltage driving circuit outputs a driving voltage to the first node in response to the gate driving signal, the light emission control signal and the data signal, and the current control circuit outputs a first driving current to the light emitting element according to the driving voltage.
For example, the voltage driving circuit may store the data voltage of the data signal provided from the data signal terminal according to the gate driving signal provided from the gate signal terminal. And may output a driving voltage to the first node based on the stored data voltage under the driving of the light emission control signal provided from the light emission control signal terminal. The current control circuit can convert the driving voltage into a first driving current and output the first driving current to the light-emitting element.
In summary, the embodiments of the present invention provide a driving method of a pixel circuit. The current control circuit in the pixel circuit can output a first driving current to the light emitting element according to the driving voltage output by the voltage driving circuit to the first node, and the current and the voltage have a linear relation due to the linear relation between the light emitting brightness and the current. Therefore, the linear relation between the luminous brightness of the luminous element and the driving voltage can be realized, the luminous brightness of the luminous element can be adjusted more conveniently, and the driving flexibility is higher.
Taking the pixel circuit shown in fig. 7 as an example, the driving principle of the pixel circuit provided in the embodiment of the present invention will be described in detail by taking the pixel circuit as an example, and taking the first switching transistor K1, the driving transistor T1, the input transistor M1, and the output transistor M2 in the pixel circuit as N-type transistors, the second switching transistor K2, and the emission control transistor L1 as P-type transistors, and the first potential is high relative to the second potential (i.e., the voltage of the signal at the first potential is greater than the voltage of the signal at the second potential).
Fig. 8 is a timing diagram of signal terminals in a pixel circuit according to an embodiment of the invention. As shown in fig. 8, in the first phase t1, the potential of the data signal provided by the data signal terminal D1 is a first potential, the potential of the first gate driving signal provided by the first gate signal terminal G11 is a first potential, and the potential of the second gate driving signal provided by the second gate signal terminal G12 is a second potential. The first and second switching transistors K1 and K2 are turned on, and the data signal terminal D1 outputs the data signal at the first potential to the third node P3 through the first and second switching transistors K1 and K2. The first phase t1 may also be referred to as a data write phase. And referring to fig. 8, in the first phase t1, the potential of the light emission control signal provided by the light emission control signal terminal EM1 is the first potential, and the light emission control transistor L1 is turned off.
In the second stage t2, the potential of the first gate driving signal jumps to the first potential, the potential of the second gate driving signal jumps to the second potential, and the first switching transistor K1 and the second switching transistor K2 are both turned off. The light emission control signal jumps to the first potential, the light emission control transistor L1 is turned on, and the second power source terminal VDD outputs the first power source signal at the first potential to the fourth node P4 through the light emission control transistor L1. Since the storage capacitor C1 may store the potential of the third node P3 in the first phase T1, in the second phase T2, the driving transistor T1 is turned on, and the driving transistor T1 may output a driving voltage to the first node P1 according to the potential of the third node P3 (i.e., the data voltage of the data signal) and the potential of the fourth node P4 (i.e., the voltage of the first power signal).
In addition, in the second phase t2, the driving voltage may become a second driving current through the first resistor R1, and at this time, the input transistor M1 and the output transistor M2 are both turned on. The second driving current passes through the input transistor M1 and the output transistor M2 to become the first driving current, and is output to the light emitting element O1, thereby driving the light emitting element O1 to emit light. This second phase t2 may also be referred to as a glow phase.
The first drive current is a constant current. Since the light-emitting luminance of the light-emitting element and the current are in a linear relationship, and the current and the voltage are in a linear relationship, the light-emitting luminance of the light-emitting element O1 and the driving voltage can be in a linear relationship. And since the driving voltage can be changed following the data voltage of the data signal, it is possible to facilitate the adjustment of the light emitting luminance of the light emitting element O1 by adjusting the data voltage of the data signal.
Also, the ratio of the width-to-length ratio of the output transistor M2 to the input transistor M1 may be greater than 1. Since the ratio of the first driving current to the second driving current is equal to the ratio of the width-to-length ratios of the output transistor M2 and the input transistor M1, by setting the ratio of the width-to-length ratios of the output transistor M2 and the input transistor M1 to a number greater than 1, a current amplification function can be realized, the light-emitting luminance of the light-emitting element O1 is further improved, and the display effect is better.
In summary, the embodiments of the present invention provide a driving method of a pixel circuit. The current control circuit in the pixel circuit can output a first driving current to the light emitting element according to the driving voltage output by the voltage driving circuit to the first node, and the current and the voltage have a linear relation due to the linear relation between the light emitting brightness and the current. Therefore, the linear relation between the luminous brightness of the luminous element and the driving voltage can be realized, the luminous brightness of the luminous element can be adjusted more conveniently, and the driving flexibility is higher.
An embodiment of the present invention provides a display substrate, which may include: a plurality of pixel units, at least one of the pixel units may each include: a light emitting element, and a pixel circuit as shown in any one of fig. 1, 3, 4, 6 and 7 coupled to the light emitting element.
An embodiment of the present invention provides a display device, which may include: the display substrate provided in the above embodiment. The display device may be: the display device comprises any product or component with a display function, such as a Micro LED display device, electronic paper, an OLED panel, an AMOLED panel, a mobile phone, a tablet computer, a television, a display, a notebook computer, a digital photo frame and the like.
Illustratively, the display device may be a microdisplay. The micro display is a display integrating thousands of pixel units on a substrate with a small size (for example, 2 inches), and the micro display can be also called a silicon-based display because the substrate is made of silicon-based material. Also, the microdisplay is widely used in various fields due to its small size, for example, in the field of Virtual Reality (VR).
It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the pixel circuit and each sub-circuit described above may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
The invention is not to be considered as limited to the particular embodiments shown and described, but is to be understood that various modifications, equivalents, improvements and the like can be made without departing from the spirit and scope of the invention.
Claims (10)
1. A pixel circuit, comprising: a voltage driving circuit and a current control circuit;
the voltage driving circuit is coupled to a gate signal terminal, a data signal terminal, a light emission control signal terminal, and a first node, respectively, and is configured to output a driving voltage to the first node in response to a gate driving signal from the gate signal terminal, a light emission control signal from the light emission control signal terminal, and a data signal from the data signal terminal;
the current control circuit is coupled to the first node and the light emitting element, and the current control circuit is configured to output a constant first driving current to the light emitting element according to the driving voltage, so that the luminance of the light emitting element and the data voltage and the driving voltage of the data signal are in a linear relationship.
2. The pixel circuit according to claim 1, wherein the current control circuit comprises: a current control sub-circuit and a current mirror circuit;
the current control sub-circuit is respectively coupled with the first node and the second node, and is used for outputting a second driving current to the second node according to the driving voltage;
the current mirror circuit is coupled to the second node and the light emitting element, respectively, and the current mirror circuit is configured to output the first driving current to the light emitting element according to the second driving current.
3. The pixel circuit according to claim 2, wherein the current control sub-circuit comprises: a first resistor;
one end of the first resistor is coupled to the first node, and the other end of the first resistor is coupled to the second node.
4. The pixel circuit according to claim 3, wherein the resistance value of the first resistor is greater than a resistance threshold value;
the resistance threshold value R satisfies:
vmin is a product of an upper limit of a gray-scale value which can be displayed by the pixel unit and a data voltage adjusting step length of the data signal, Rgs is a gate-source resistance value of a driving transistor in the voltage driving circuit, Vd is an upper limit voltage of the data signal, and Vth is a threshold voltage of the driving transistor.
5. The pixel circuit according to claim 2, wherein the current mirror circuit comprises: an input transistor and an output transistor;
a gate and a first pole of the input transistor are both coupled to the second node, and a second pole of the input transistor is coupled to a first power supply terminal;
a gate of the output transistor is coupled to the second node, a first pole of the output transistor is coupled to the first power supply terminal, and a second pole of the output transistor is coupled to the light emitting element.
6. The pixel circuit according to claim 5, wherein a ratio of a width-to-length ratio of the output transistor to the input transistor is greater than 1.
7. The pixel circuit according to any of claims 1 to 6, wherein the voltage driving circuit comprises: a data writing sub-circuit, a light emission control sub-circuit, a storage sub-circuit, and a driving sub-circuit;
the data writing sub-circuit is respectively coupled with the gate signal terminal, the data signal terminal and a third node, and is used for responding to the gate driving signal and outputting the data signal to the third node;
the light-emitting control sub-circuit is respectively coupled with the light-emitting control signal terminal, the second power terminal and the fourth node, and is configured to output a second power signal provided by the second power terminal to the fourth node in response to the light-emitting control signal;
the storage sub-circuit is coupled to the third node, the storage sub-circuit being configured to control a voltage of the third node;
the driving sub-circuit is respectively coupled with the third node, the fourth node and the first node, and is used for outputting a driving voltage to the first node under the driving of the third node and the fourth node.
8. A driving method of a pixel circuit, applied to the pixel circuit according to any one of claims 1 to 7, the method comprising:
the gate signal terminal provides a gate driving signal, the light emission control signal terminal provides a light emission control signal, the data signal terminal provides a data signal, the voltage driving circuit outputs a driving voltage to the first node in response to the gate driving signal, the light emission control signal and the data signal, and the current control circuit outputs a first driving current to the light emitting element according to the driving voltage.
9. A display substrate, comprising: a plurality of pixel cells, at least one of the pixel cells comprising: a light emitting element, and a pixel circuit according to any one of claims 1 to 7 coupled to the light emitting element.
10. A display device, characterized in that the display device comprises: the display substrate of claim 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910239895.7A CN109754756B (en) | 2019-03-27 | 2019-03-27 | Pixel circuit, driving method thereof, display substrate and display device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910239895.7A CN109754756B (en) | 2019-03-27 | 2019-03-27 | Pixel circuit, driving method thereof, display substrate and display device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109754756A CN109754756A (en) | 2019-05-14 |
| CN109754756B true CN109754756B (en) | 2020-06-30 |
Family
ID=66409460
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910239895.7A Active CN109754756B (en) | 2019-03-27 | 2019-03-27 | Pixel circuit, driving method thereof, display substrate and display device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109754756B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110148376B (en) * | 2019-06-04 | 2020-11-06 | 京东方科技集团股份有限公司 | Pixel circuit, driving method thereof, display panel and display device |
| WO2021184307A1 (en) * | 2020-03-19 | 2021-09-23 | 京东方科技集团股份有限公司 | Display substrate and display apparatus |
| WO2021184300A1 (en) | 2020-03-19 | 2021-09-23 | 京东方科技集团股份有限公司 | Display panel and display device |
| WO2022174404A1 (en) * | 2021-02-20 | 2022-08-25 | 京东方科技集团股份有限公司 | Display panel and display device |
| US20220344428A1 (en) * | 2021-02-23 | 2022-10-27 | Boe Technology Group Co., Ltd. | Display panel and display device |
| CN113674701A (en) * | 2021-08-02 | 2021-11-19 | Tcl华星光电技术有限公司 | Pixel driving circuit and mobile terminal |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101097680A (en) * | 2006-06-30 | 2008-01-02 | Lg.菲利浦Lcd株式会社 | Organic light-emitting diode display device and driving method thereof |
| CN105139799A (en) * | 2015-06-26 | 2015-12-09 | 中山大学 | AMOLED display pixel point driving circuit and method |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104200776B (en) * | 2014-09-25 | 2017-02-15 | 武汉精测电子技术股份有限公司 | Pixel driving circuit and driving method for improving Mura defect of OLED panel |
| CN205282056U (en) * | 2016-01-04 | 2016-06-01 | 京东方科技集团股份有限公司 | Pixel circuit and display device |
| CN105679245B (en) * | 2016-03-31 | 2018-06-08 | 上海天马有机发光显示技术有限公司 | A kind of pixel compensation circuit and dot structure |
| CN107424555B (en) * | 2017-05-23 | 2021-08-24 | 上海和辉光电股份有限公司 | Pixel circuit, driving method and display |
| CN110473496B (en) * | 2018-05-09 | 2021-01-26 | 京东方科技集团股份有限公司 | Pixel circuit, driving method thereof, display substrate and display device |
| CN108877668B (en) * | 2018-07-27 | 2021-01-22 | 京东方科技集团股份有限公司 | Pixel circuit, driving method thereof and display panel |
-
2019
- 2019-03-27 CN CN201910239895.7A patent/CN109754756B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101097680A (en) * | 2006-06-30 | 2008-01-02 | Lg.菲利浦Lcd株式会社 | Organic light-emitting diode display device and driving method thereof |
| CN105139799A (en) * | 2015-06-26 | 2015-12-09 | 中山大学 | AMOLED display pixel point driving circuit and method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109754756A (en) | 2019-05-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109754756B (en) | Pixel circuit, driving method thereof, display substrate and display device | |
| CN109801592B (en) | Pixel circuit, driving method thereof and display substrate | |
| CN106910460B (en) | Pixel-driving circuit and display panel | |
| CN107025883B (en) | Display panel, pixel-driving circuit and its driving method | |
| CN107464526B (en) | Pixel compensation circuit, driving method thereof and display device | |
| CN110473496B (en) | Pixel circuit, driving method thereof, display substrate and display device | |
| CN109887464B (en) | Pixel circuit, driving method thereof, display panel and display device | |
| CN107369413B (en) | Pixel compensation circuit, driving method thereof, display panel and display device | |
| JP2020519925A (en) | Pixel driving circuit, pixel driving method, and display device | |
| CN111223443B (en) | Pixel circuit, driving method thereof, display substrate and display device | |
| CN110728946A (en) | Pixel circuit, driving method thereof and display panel | |
| CN111477162B (en) | Pixel circuit, driving method thereof and display device | |
| CN111243498B (en) | Pixel circuit, driving method thereof and display device | |
| WO2020181512A1 (en) | Pixel circuit and driving method therefor, and display apparatus | |
| CN110010076B (en) | Pixel circuit, driving method thereof, display substrate and display device | |
| CN107516488A (en) | A kind of image element circuit, its driving method, display panel and display device | |
| CN110223639B (en) | Pixel circuit, pixel driving method, display substrate and display device | |
| WO2020187158A1 (en) | Pixel driving circuit, display panel and driving method thereof, and display device | |
| CN101673509A (en) | Display apparatus | |
| CN113851082B (en) | Pixel driving circuit, driving method thereof and display panel | |
| CN112992071A (en) | Pixel circuit, driving method thereof and display device | |
| CN111754941A (en) | Pixel circuit, driving method thereof, display substrate and display device | |
| CN115035858A (en) | Pixel circuit, driving method thereof and display panel | |
| CN112164375A (en) | Pixel compensation circuit, driving method thereof and display device | |
| CN108877684B (en) | Pixel circuit and driving method thereof, array substrate, display panel and display device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| TA01 | Transfer of patent application right | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20200212 Address after: 100015 Jiuxianqiao Road, Beijing, No. 10, No. Applicant after: BOE TECHNOLOGY GROUP Co.,Ltd. Applicant after: Kunming BOE Display Technology Co., Ltd. Address before: 100015 Jiuxianqiao Road, Beijing, No. 10, No. Applicant before: BOE TECHNOLOGY GROUP Co.,Ltd. |
|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CP01 | Change in the name or title of a patent holder | ||
| CP01 | Change in the name or title of a patent holder |
Address after: 100015 Jiuxianqiao Road, Beijing, No. 10, No. Patentee after: BOE TECHNOLOGY GROUP Co.,Ltd. Patentee after: Yunnan chuangshijie Optoelectronic Technology Co., Ltd Address before: 100015 Jiuxianqiao Road, Beijing, No. 10, No. Patentee before: BOE TECHNOLOGY GROUP Co.,Ltd. Patentee before: Kunming BOE Display Technology Co.,Ltd. |