CN213904897U

CN213904897U - Pixel circuit and display device

Info

Publication number: CN213904897U
Application number: CN202022747172.9U
Authority: CN
Inventors: 孙丽娜
Original assignee: Individual
Current assignee: Tianyi Microelectronics (Hangzhou) Co.,Ltd.
Priority date: 2020-11-24
Filing date: 2020-11-24
Publication date: 2021-08-06
Anticipated expiration: 2030-11-24

Abstract

The utility model discloses a pixel circuit and a display device, wherein the pixel circuit comprises a light-emitting element; the first switch tube controls the writing of data voltage; a second switch tube for controlling the light emitting time of the light emitting element; a driving tube for making the light emitting element emit light; the third switching tube controls the initialization of the driving tube; the fourth switching tube resets the voltage of the anode of the light-emitting element; the first capacitor and the second capacitor are used for storing the actual threshold voltage of the driving tube after the initialization phase; in the data voltage writing stage, attenuating the data voltage through a first capacitor and a second capacitor, and storing the attenuated voltage into the first capacitor; and in the light-emitting stage, the driving tube enables the light-emitting element to emit light based on the data voltage and the power supply voltage attenuated in the first capacitor. The pixel circuit structure of 5T2C in this application combines control signal, has solved the inhomogeneous problem of luminance because of the dispersion of drive tube threshold voltage and the voltage drop of power supply causes to the scope of gamma voltage has been expanded, has promoted display quality.

Description

Pixel circuit and display device

Technical Field

The utility model relates to a show technical field, more specifically relates to a pixel circuit and display device thereof.

Background

An Organic Light Emitting Diode (OLED) is widely used in the field of display devices because it has characteristics of self-luminescence, wide viewing angle display, fast response, and being capable of being manufactured on a flexible substrate. The display panel of the OLED display device is composed of a plurality of pixel circuit structures, and a common pixel circuit of the OLED display panel includes a light emitting element (OLED), a driving tube, a first switching tube, and a first capacitor. The control end of the first switch tube is connected with the scanning line and receives scanning signals, the first path end of the first switch tube is connected with the data line and receives data voltage, and the second path end of the first switch tube is connected with the control end of the driving tube. The first path end of the driving tube is connected with a power line and receives power voltage, and the second path end of the driving tube is connected with the anode of the light-emitting element. The cathode of the light emitting element is connected to a common voltage line and receives a common voltage. One end of the first capacitor is connected with the second path end of the first switch tube, and the other end of the first capacitor is connected with the second path end of the driving tube. The light emitting element OLED is driven to operate in a writing phase and a light emitting phase. In the writing stage, the first switch tube is conducted, and the data voltage is written into the light-emitting element and stored in the first storage capacitor. In the light-emitting stage, the first switch tube is switched off, the driving tube is switched on, and the light-emitting element is controlled to emit light, so that the picture display is realized.

However, the difference in the threshold voltage of the driving tube between different pixel circuits in the display panel or the drift of the threshold voltage of the driving tube in the pixel circuit with time may cause the difference in the current of the light emitting element OLED of each pixel circuit, which may further cause the display panel to have poor uniformity of the display brightness and poor picture quality.

At present, for a pixel circuit composed of thin film transistors, an improvement scheme aiming at the non-uniformity of the threshold voltage of the thin film transistor, the drift of the threshold voltage of the thin film transistor and the non-uniformity of the electrical performance of the light emitting element OLED is made, and a control switch tube for reading the threshold voltage and correspondingly compensating is additionally arranged in the pixel circuit, so that the display effect is improved. However, the mobility of the single-crystal silicon CMOS transistor is very high, and the required light emitting current of each pixel in the silicon-based micro OLED display panel is very small, and the gate voltage range of the driving transistor is very narrow due to the improvement scheme provided by the prior art, so that the gamma voltage accuracy is not sufficient, and the picture gray scale display effect is poor.

Further, a pixel circuit and a display device thereof are needed to solve the above technical problems.

SUMMERY OF THE UTILITY MODEL

In order to solve the problems existing in the prior art, the present invention adopts a 5T2C pixel circuit.

According to the utility model provides a pixel circuit is provided, include: a light emitting element;

the first switch tube is controlled by a scanning signal when being switched on and switched off, and is used for controlling data voltage writing when being switched on;

the second switch tube is controlled by a dimming control signal when being switched on and switched off and is used for controlling the light-emitting time of the light-emitting element;

a driving tube supplying a driving current or a driving voltage to an anode of the light emitting element to cause the light emitting element to emit light;

the on and off of the third switching tube is controlled by an initialization control signal, and the third switching tube is used for controlling the driving tube to initialize when being switched on;

the fourth switching tube is controlled by a discharge control signal in a switching-on and switching-off mode, and periodically resets the voltage of the anode of the light-emitting element;

a first capacitor for storing the actual threshold voltage of the driving tube after the initialization phase of the driving tube, and providing the voltage stored in the data voltage writing phase of the first capacitor to the driving tube during the light emitting phase of the light emitting element; and

a second capacitor attenuating the data voltage by a proportional coefficient with the first capacitor in the data voltage writing stage and storing the attenuated voltage to the first capacitor,

the driving tube provides the driving current or the driving voltage based on the attenuated data voltage provided by the first capacitor and the power voltage received by the second switch tube.

Optionally, the control end of the first switch tube is connected to the scan line to receive the scan signal, the first pass end of the first switch tube is connected to the data line to receive the data signal, the first pass ends of the first switch tubes in the pixel circuits in the same column in the pixel array are connected to a data line, and the control ends of the first switch tubes in the pixel circuits in the same row in the pixel array are connected to a scan line;

the control end of the second switch tube receives the dimming control signal, the first path end of the second switch tube is connected with a power line to receive the power voltage, the control ends of the second switch tubes in the pixel circuits in the same row in the pixel array share one dimming control signal, and the first path ends of the second switch tubes in the pixel circuits in the whole pixel array share one power voltage;

the control end of the driving tube is connected with the second channel end of the first switching tube, the first channel end of the driving tube is connected with the second channel end of the second switching tube, and the second channel end of the driving tube is connected with the anode of the light-emitting element;

a third switching tube, a control end of which receives the initialization control signal, a first path end of which receives an initialization voltage, a second path end of which is connected with the control end of the driving tube, control ends of the third switching tubes in the pixel circuits of the same row in the pixel array share one initialization control signal, and the first path ends of the third switching tubes in the pixel circuits in the whole pixel array share one initialization voltage;

a control end of the fourth switching tube receives the discharge control signal, a first access end of the fourth switching tube receives and releases a discharge voltage, a second access end of the fourth switching tube is connected with a second access end of the driving tube, control ends of the fourth switching tubes in the pixel circuits in the same row in the pixel array share one discharge control signal, and first access ends of the fourth switching tubes in the pixel circuits in the whole pixel array share one discharge voltage;

the first capacitor is connected between the control end of the driving tube and the first passage tube of the driving tube; and

the second capacitor is connected between the first passage end of the driving tube and the second passage end of the driving tube;

and a light emitting element whose cathode receives a common voltage.

Optionally, the initialization voltage is a constant voltage, and a voltage value of the constant voltage is smaller than a difference between the power supply voltage and an absolute value of a threshold voltage of the driving pipe mark.

Optionally, the initialization control signal is a scan signal for controlling the pixel circuits in the previous row.

Optionally, the discharge voltage is a constant voltage, and a difference between a voltage value of the constant voltage and a cathode voltage of the light emitting element is smaller than an on voltage of the light emitting element.

Optionally, the first and second capacitors are metal-insulator-metal (MIM) type capacitors, wherein the first and second capacitors are stacked capacitors.

According to another aspect of the present invention, there is provided a display device, comprising a plurality of pixel circuits as described above, wherein the plurality of pixel circuits are arranged in an array.

Optionally, the display device is a silicon-based micro OLED display device.

The embodiment of the utility model provides a current mode driven pixel circuit, including first switch tube, second switch tube, third switch tube, fourth switch tube, first electric capacity, second electric capacity, light emitting component, drive tube, the circuit integrated level is high, is applicable to high ppi's silicon-based miniature OLED display. The utility model provides a pixel circuit structure combines pixel circuit's control signal for example scanning signal, initialization control signal, discharge control signal, dimming control signal's chronogenesis relation can compensate because the demonstration that the driving tube threshold voltage inconsistency leads to is inhomogeneous, can compensate because the demonstration that the electric characteristic difference of showing that voltage drop on the power cord leads to is inhomogeneous and light-emitting component OLED itself leads to is inhomogeneous. In addition, the utility model discloses in the time sequence relation that the mode that sets up of first electric capacity and second electric capacity combines control signal can also expand gamma voltage's scope to and reduce the transistor electric leakage to the harmful effects of luminance and contrast, make the utility model discloses a pixel circuit is applicable to silica-based OLED microdisplay more.

It should be noted that the anode voltage of the light emitting element OLED can be periodically reset by controlling the fourth switching tube through the discharge control signal, so as to increase the dynamic contrast and prevent the smear caused by the charge on the anode that cannot be discharged quickly when the pixel light is converted from the bright state to the dark state. Meanwhile, the service life of the OLED device can be prolonged by periodically resetting the anode voltage of the light-emitting element OLED, and the phenomenon of image sticking is reduced.

It should be noted that, the existence of the second capacitor also makes the voltage rise of the leakage current of the fourth switching tube and the driving tube on the light emitting element very slow in the light emitting stage, so that the black picture display is less affected by the leakage current, and the black state is darker. Meanwhile, the second capacitor C2 is small, so that the display time of high gray scale is not affected.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings.

Fig. 1 shows a schematic structural diagram of a pixel circuit provided in an embodiment of the present application.

Fig. 2 shows a timing diagram of a pixel circuit provided in an embodiment of the present application.

Fig. 3 shows a flow chart of a pixel circuit driving method provided by an embodiment of the present application.

Detailed Description

The invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by like reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale. Moreover, certain well-known elements may not be shown in the figures.

Numerous specific details of the invention, such as structure, materials, dimensions, processing techniques and techniques of the devices are described below in order to provide a more thorough understanding of the invention. However, as will be understood by those skilled in the art, the present invention may be practiced without these specific details.

It should be understood that, in the embodiments of the present application, a and B are connected/coupled, which means that a and B may be connected in series or in parallel, or a and B may pass through other devices, and the embodiments of the present application do not limit this.

The pixel circuit provided by the application comprises a switching tube and a driving tube which are transistors, wherein the transistors are monocrystalline silicon CMOS transistors, and the pixel circuit is a pixel circuit in a silicon-based micro OLED display panel. The display area of the silicon-based micro OLED display panel includes a plurality of pixel circuits arranged in an array, for example.

Embodiments of a pixel circuit and a display device provided in the present application will be described below with reference to the accompanying drawings.

Fig. 1 shows a schematic structural diagram of a pixel circuit provided in an embodiment of the present application, and fig. 2 shows a timing diagram of the pixel circuit provided in the embodiment of the present application.

As shown in fig. 1, the pixel circuit 100 in the OLED display panel includes a first switching tube SW1, a driving tube DRV1, a light emitting element OLED, a first capacitor C1, a second capacitor C2, a second switching tube SW2, a third switching tube SW3, and a fourth switching tube SW 4. The first switch SW1 is turned on and off by the SCANB signal for controlling the writing of the DATA voltage DATA. The on and off of the second switch SW2 is controlled by the dimming control signal EMB for controlling the light emitting time of the light emitting element OLED. The driving tube DRV1 provides a driving current or a driving voltage to the anode of the light emitting element OLED based on the DATA voltage DATA and the power voltage AVDD received via the second switching tube SW2 to make the light emitting element OLED emit light, so that the pixel circuit 100 supports an analog gamma curve to adjust the brightness and a pulse width to adjust the brightness. The on and off of the third switch SW3 is controlled by an initialization control signal INITB, and is used to initialize the driving transistor DRV1 when turned on. The on and off of the fourth switching tube SW4 is controlled by the discharge control signal DSB to periodically reset the voltage of the anode of the light emitting element OLED. The first capacitor C1 stores the actual threshold voltage VTH1 of the driving transistor DRV1 during the initialization phase of the driving transistor DRV1, and stores the attenuation value of the DATA voltage DATA through the first capacitor and the second capacitor during the DATA voltage DATA writing phase of the pixel circuit. The second capacitor C2 performs the DATA voltage DATA decay by a scaling factor with the first capacitor C1. In the light emitting phase of the light emitting element, the driving transistor DRV1 makes the light emitting element OLED emit light based on the attenuated data voltage stored in the first capacitor C1 in the data voltage writing phase and the power voltage AVDD received through the second switching transistor SW 2.

Specifically, a control terminal of the first switch SW1 is connected to a scan line and receives a scan signal SCANB, a first path terminal of the first switch SW1 is connected to a DATA line and receives a DATA voltage DATA, and a second path terminal of the first switch SW1 is connected to a control terminal of the driving transistor DRV1, wherein a connection node between the second path terminal of the first switch SW1 and the control terminal of the driving transistor DRV1 is a first node N1.

The control terminal of the second switch SW2 receives the dimming control signal EMB, the first path terminal of the second switch SW2 is connected to the power line and receives the power voltage AVDD, and the second path terminal of the second switch SW2 is used as the second node N2.

The first path terminal of the driving transistor DRV1 is connected to the second node N2, is connected to the power line via the second switching transistor SW2, and receives the power supply voltage AVDD, and the second path terminal of the driving transistor DRV1 is connected to the anode of the light emitting element OLED as the third node N3. The cathode of the light emitting diode OLED is connected to a common voltage line and receives a common voltage VCOM.

The first capacitor C1 is connected between the first node N1 and the second node N2, i.e., the first capacitor C1 is connected between the control terminal of the driving transistor DRV1 and the first path terminal.

The second capacitor C2 is connected between the second node N2 and the third node N3, i.e., the second capacitor C2 is connected between the first path terminal and the second path terminal of the driving transistor DRV 1.

A control terminal of the third switch SW3 receives the initialization control signal INITB, a first path terminal of the third switch SW3 receives the initialization voltage VREF, and a second path terminal of the third switch SW3 is connected to the first node N1.

The control end of the fourth switching tube SW4 is connected with a receiving and releasing control signal DSB, the first path end of the fourth switching tube SW4 is connected with a receiving and releasing voltage VDSCHG, and the second path end of the fourth switching tube SW4 is connected with a third node N3.

It should be noted that the voltage difference between the discharge voltage VDSCHG and the common voltage VCOM is smaller than the turn-on voltage of the light emitting element OLED. The initialization voltage VREF is less than the difference between the supply voltage AVDD and the absolute value VTHP of the target threshold voltage of the driver tube DRV 1. In the present embodiment, the initialization voltage VREF is, for example, 3V. The initialization voltage VREF, the discharge voltage VDSCHG, the power supply voltage AVDD, and the common voltage VCOM are common to all pixel circuits in the display region in the entire display panel. A scan signal SCANB is shared by the pixel circuits in the same row, a discharge control signal DSB is shared by the pixel circuits in the same row, an initialization control signal INITB is shared by the pixel circuits in the same row, and a dimming control signal EMB is shared by the pixel circuits in the same row. One DATA voltage DATA is shared by the pixel circuits located in the same column. The first capacitor C1 and the second capacitor C2 are storage capacitors, and may be MOS (metal-oxide-semiconductor) capacitors or MIM (metal-insulator-metal) capacitors. In a preferred embodiment, the first capacitor C1 and the second capacitor C2 are MIM metal capacitors, which may be stacked capacitors integrated on MOS transistors, and do not occupy the area of a pixel circuit, thereby reducing the overall area of a display panel, better realizing miniaturization of a display device, and making the capacitance ratio more consistent.

It should be noted that the source and the drain of the driving transistor DRV1, the first switching transistor SW1, the second switching transistor SW2, the third switching transistor SW3, and the fourth switching transistor SW4 are symmetrical, so the source and the drain can be interchanged. Further, the control terminal of the transistor is a gate, and the first and second path terminals thereof are a source and a drain, respectively, or a drain and a source, respectively. In the present embodiment, the driving transistor DRV1, the first switch transistor SW1, the second switch transistor SW2, the third switch transistor SW3 and the fourth switch transistor SW4 are all P-type transistors. However, in the case of process support, the N-type transistor may be used instead, and accordingly, the polarity of the control signal needs to be changed.

Next, with reference to fig. 2, the operation principle of the pixel circuit 100 will be described with reference to a timing chart of the pixel circuit 100. The pixel circuit 100 mainly operates in the initialization and threshold voltage extraction phase, the data voltage writing phase, and the light emission phase in one operation cycle.

In the initialization and threshold voltage extraction stage T1, the initialization control signal INITB is at an active level state, the discharge control signal DSB is at an active level state, the dimming control signal EMB is at an inactive level state, and the scan signal SCANB is at an inactive level state. And further controls the first switch tube SW1 to be turned off, the second switch tube SW2 to be turned off, the third switch tube SW3 to be turned on and the fourth switch tube SW4 to be turned on. The initialization voltage VREF is further written into the first node N1, the second node N2 is disconnected from the power supply voltage AVDD due to the disconnection of the second switch tube SW2, the voltage value at the second node N2 is decreased and approaches the sum of the initialization voltage VREF and the actual threshold voltage VTH1 of the driving tube DRV1 due to the leakage of the driving tube DRV1, and the discharge voltage VDSCHG is written into the third node N3. The actual threshold voltage VTH1 of the driving transistor DRV1 is stored in the first capacitor C1, which is completed before the data writing phase because the voltage at the second node N2 is dropped for a longer time. The actual threshold voltage VTH1 is (1+ m) × VTH, m is lamda (AVDD-VN2), m is the influence coefficient of the substrate bias effect, and VN2 is the voltage value at the second node N2.

In the write phase T2, the initialization control signal INITB is at an inactive level, the discharge control signal DSB is at an active level, the dimming control signal EMB is at an inactive level, and the scan signal SCANB is at an active level. And further controls the first switch tube SW1 to be conducted, the second switch tube SW2 to be disconnected, the third switch tube SW3 to be disconnected and the fourth switch tube SW4 to be conducted. Further, the voltage value VN1 at the first node N1 becomes DATA, and the DATA writing is completed. The voltage at the second node N2 is the voltage division of the DATA voltage DATA across the first capacitor C1 and the second capacitor C2, and has a voltage value VN2 ═ VREF + VTH1+ α (DATA — VREF), where α ═ C1/(C1+ C2). The attenuated voltage of the DATA voltage DATA is stored across the first capacitor C1 at the end of the DATA voltage write phase.

In the light-emitting period T3, the initialization control signal INITB changes to the inactive level state, the discharge control signal DSB changes to the inactive level state, the dimming control signal EMB changes to the active level state, and the scan signal SCANB changes to the inactive level state. And further controlling the first switch tube SW1 to be turned off, the second switch tube SW2 to be turned on, the third switch tube SW3 to be turned off, the fourth switch tube SW4 to be turned off, and the driving tube DRV1 to provide a driving current or a driving voltage based on the attenuated data voltage and the power voltage AVDD stored in the first capacitor C1 to make the light-emitting element OLED emit light. Further, the voltage VN2 at the second node is AVDD, and the voltage VN1 at the first node N1 is DATA + β (AVDD- (VREF + VTH1+ α (DATA-VREF))) (1- α β) DATA + β AVDD- β VTH1- β VREF + α β VREF. Because β ═ C1/(C1+ Cpn1), Cpn1 is the parasitic capacitance of the first node N1. C1> > Cpn1, β ≈ 1, then VN1 ═ 1- α) DATA + AVDD-VTH1- (1- α) VREF. When the load is large current, the driver works in a saturation region, Ioled is K (Vgs-VTHP) 2K (AVDD-VN1-VTHP) 2K ((1-alpha) VREF- (1-alpha) DA TA + m VTHP) 2, the load current Ioled is irrelevant to AVDD, the relevance of the target threshold value VTHP of the driving tube DRV1 is greatly reduced, and the range of gamma voltage is expanded. Wherein, C1/C2 can be 1: 1, or 1: 2, or 2: 1 or other ratio. When the same load current Ioled is provided, the range of the DATA voltage DATA of the pixel circuit 100 provided in the present application is wider, and thus the range of the gamma voltage can be extended. According to the formula α ═ C1/(C1+ C2), where the larger α is, the less the load current Ioled is affected by the DATA voltage DATA, and thus the expansion range of the gamma voltage is larger. And then can obtain better dimming effect, promoted the quality of picture display. Where K is a factor related to the size of the drive tube DRV1 and the semiconductor process.

In an alternative embodiment, the initialization control signal INITB is the scan signal SCANB outputted from the previous scan line, which reduces the design complexity of the line scan controller in the display device.

It should be noted that the discharge control signal DSB can periodically reset the anode voltage of the light emitting element OLED, so as to increase the dynamic contrast and prevent the charge on the anode from being discharged quickly to cause a smear when the pixel emits light from a bright state to a dark state. Meanwhile, the service life of the OLED device can be prolonged by periodically resetting the anode voltage of the light-emitting element OLED, and the phenomenon of image sticking is reduced. And by controlling the on-time of the second switch tube SW2 and the off-time of the fourth switch tube SW4, the light emitting time of the light emitting element OLED can be further controlled, so as to adjust the brightness of the display device without changing the gamma curve.

It should be noted that the existence of the second capacitor C2 can make the voltage rise of the leakage current of the fourth switch transistor SW4 and the driving transistor DRV1 on the light emitting element become very slow, so that the black screen display is less affected by the leakage current, and the black state is darker. Meanwhile, the second capacitor C2 is small, so that the display time of high gray scale is not affected.

As shown in fig. 3, the driving method of the pixel circuit includes the steps of:

step S10: in an initialization and threshold voltage extraction phase, the actual threshold voltage of the drive tube in the pixel circuit is stored by the first capacitor after initialization. The initialization control signal INITB is in an active level state, the discharge control signal DSB is in an active level state, the dimming control signal EMB is in an inactive level state, and the scan signal SCANB is in an inactive level state. And further controls the first switch tube SW1 to be turned off, the second switch tube SW2 to be turned off, the third switch tube SW3 to be turned on and the fourth switch tube SW4 to be turned on. The drive tube DRV1 is disconnected. The writing initialization voltage VREF is controlled by the third switching tube at the first node N1, and the actual threshold voltage of the driving tube DRV1 is stored into the first capacitor C1 after the voltage value at the second node N2 is reduced.

Step S20: and in the data voltage writing stage, storing the attenuated data voltage through the first capacitor. The initialization control signal INITB is in an inactive level state, the discharge control signal DSB is in an active level state, the dimming control signal EMB is in an inactive level state, and the scan signal SCANB is changed to an active level state. And further controlling the first switch tube SW1 to be conducted, the second switch tube SW2 to be disconnected, the third switch tube SW3 to be disconnected, the fourth switch tube SW4 to be conducted and the driving tube DRV1 to be disconnected. The voltage of the DATA voltage DATA after a certain attenuation ratio is written into the first node N1 and stored via the first capacitor.

Step S30: in the light emitting stage, the driving tube supplies a driving current or a driving voltage to the light emitting element based on the attenuated data voltage and the power supply voltage stored in the first capacitor. The initialization control signal INITB is in an inactive level state, the discharge control signal DSB is changed to an inactive level state, the dimming control signal EMB is changed to an active level state, and the scan signal SCANB is changed to an inactive level state. And further controlling the first switch tube SW1 to be switched off, the second switch tube SW2 to be switched on, the third switch tube SW3 to be switched off, the fourth switch tube SW4 to be switched off, and the driving tube DRV1 to be switched on or switched off based on the DATA voltage DATA. The second switch tube SW2 is turned on or off, so that the light emitting time can be controlled, and the dimming function is realized. And based on the setting of the second capacitor, the influence of leakage current can be reduced when a black picture is displayed, and the black state is darker.

Further, the method further includes resetting the voltage of the anode of the light emitting element at least in the initialization phase and the data voltage writing phase. That is, in the present embodiment, the fourth switching tube SW4 is turned on during the initialization phase and the data voltage writing phase, and discharges the anode of the light emitting element OLED.

The present application also provides a display device having a pixel circuit in a display panel as provided in the above embodiments.

Also, those of ordinary skill in the art will recognize that the various example structures described in connection with the embodiments disclosed herein can be implemented with various configurations or adjustments, with each structure or reasonable variations of the structure, but such implementations should not be considered as beyond the scope of the present application. Furthermore, it should be understood that the connection relationship between the various components of the amplifier in the foregoing figures in this application embodiment is an illustrative example, and does not set any limit to this application embodiment.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

In accordance with the embodiments of the present invention as set forth above, these embodiments are not exhaustive and do not limit the invention to the precise embodiments described. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and its various embodiments with various modifications as are suited to the particular use contemplated. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A pixel circuit, comprising:

a light emitting element;

2. The pixel circuit according to claim 1,

the control end of the first switch tube is connected with the scanning line to receive the scanning signal, the first access end of the first switch tube is connected with the data line to receive the data voltage, the first access ends of the first switch tubes in the pixel circuits of the same column in the pixel array are connected with a data line together, and the control ends of the first switch tubes in the pixel circuits of the same row in the pixel array are connected with a scanning line together;

and a light emitting element whose cathode receives a common voltage.

3. The pixel circuit of claim 2, wherein the initialization voltage is a constant voltage having a voltage value less than the absolute value of the difference between the power supply voltage and the target threshold voltage of the driving transistor.

4. The pixel circuit according to claim 1, wherein the initialization control signal is a scan signal for controlling a previous row of pixel circuits.

5. The pixel circuit according to claim 2, wherein the discharge voltage is a constant voltage, and a difference between a voltage value of the constant voltage and a cathode voltage of the light emitting element is smaller than an on voltage of the light emitting element.

6. The pixel circuit according to claim 1, wherein the first and second capacitors are metal-insulator-metal type capacitors, wherein the first and second capacitors are stacked capacitors.

7. A display device comprising a plurality of pixel circuits according to any one of claims 1 to 6, the plurality of pixel circuits being arranged in an array.

8. The display device of claim 7, wherein the display device is a silicon-based micro OLED display device.