CN108492778A - A kind of pixel circuit, organic electroluminescence panel and display device - Google Patents

This application involves a kind of display technology field more particularly to pixel circuit, organic electroluminescence panel and display devices.This application includes：Luminescent device, initialization module, charging module, compensating module, light emitting control module；Under the control of the first scanning signal end, third scanning signal end, the 4th scanning signal end and data signal end, initialization module respectively initializes charging module and luminescent device；Under the control of third scanning signal end and the first data signal end, charged to charging module by compensating module；Under the control at direct current signal end, light emitting control module controls charging module driving luminescent device and shines.To by being initialized to luminescent device, ensure that luminescent device can thoroughly reach dark-state in time, avoid display ghost problem, promote display quality；It can also realize circuit compensation function, ensure that driving current is uncorrelated to the threshold voltage of driving transistor device in charging module, effectively promote show uniformity.

A kind of pixel circuit, organic electroluminescence panel and display device

Technical field

This application involves a kind of display technology field more particularly to pixel circuit, organic electroluminescence panel and display dresses It sets.

Background technology

Organic light emitting display (Organic Light Emitting Diode, OLED) is current flat-panel monitor research One of the hot spot in field, OLED have many advantages, such as low low energy consumption, production cost, self-luminous, wide viewing angle and fast response time.OLED Belong to electric current driving, needs stable electric current luminous to control.Due to manufacturing process and device aging etc., pixel can be made electric The threshold voltage V of the driving transistor on road_thThere are inhomogeneities, and which results in the electric current hairs for flowing through each pixel OLED Changing is so that display brightness is uneven, to influence the display effect of whole image.Currently, can be by increasing driving transistor Number compensates to form new pixel circuit, for example, by using 6T1C.

However, existing 6T1C cannot achieve the reversed initialization to luminescent device voltage, cause display interface that can be detained The picture of previous frame causes display ghost, influences display quality.

Invention content

A kind of pixel circuit of the embodiment of the present application offer, organic electroluminescence panel and display device, it is existing to solve Drawbacks described above present in technology.

In order to solve the above-mentioned technical problem, the embodiment of the present application uses following technical proposals：

A kind of pixel circuit, including：Luminescent device, initialization module, charging module, compensating module, light emitting control module； Wherein：

The first input end of the initialization module is defeated with the first of the first data signal end and the compensating module respectively Enter end connection, the second input terminal of the initialization module is connect with the second scanning signal end, the third of the initialization module Input terminal is connect with the second input terminal of third scanning signal end and the compensating module respectively, and the 4th of the initialization module the Input terminal is connect with the 4th scanning signal end, the 5th input terminal of the initialization module and the output end with the charging module Connection, the output end of the initialization module are connect with the anode of the luminescent device, the cathode of shown luminescent device and second Data signal end connects；

The first input end of the charging module respectively with the output end of the compensating module and the light emitting control module Output end connection, the second input terminal of the charging module connect with direct current signal end；

The first input end of the light emitting control module is connect with the first scanning signal end, and the of the light emitting control module Two input terminals are connect with the direct current signal end；

In first scanning signal end, third scanning signal end, the 4th scanning signal end and data signal end Control under, the initialization module respectively initializes the charging module and the luminescent device；In the third Under the control of scanning signal end and first data signal end, the charging module is filled by the compensating module Electricity；Under the control at the direct current signal end, the light emitting control module controls the charging module and drives the luminescent device It shines.

Optionally, the charging module includes：Driving transistor and capacitance；Wherein, the input terminal of the driving transistor It is connect respectively with the output end of the output end of the compensating module and the light emitting control module, the control of the driving transistor End respectively with the first end of the capacitance, the input of the output end and the second switch transistor of the first switch transistor The output end of end connection, the driving transistor is brilliant with the output end of the second switch transistor and third switch respectively The input terminal of body pipe connects；

The second end of the capacitance connects with the first input end of the direct current signal end and the light emitting control module respectively It connects.

Optionally, the driving transistor is P-type transistor.

Optionally, the initialization module includes：First switch transistor, second switch transistor and third switch crystal Pipe；Wherein, the input terminal of the first switch transistor is defeated with first data signal end and the compensating module respectively Enter end connection, the control terminal of the first switch transistor is connect with second scanning signal end, the first switch crystal The output end of pipe is connect with the input terminal of the second switch transistor；

The control terminal of the second switch transistor respectively with third scanning signal end and the compensating module Two input terminals connect, the output end of the second switch transistor respectively with the input terminal of the third switching transistor and described The output end of charging module connects；

The control terminal of the third switching transistor is connect with the 4th scanning signal end, the third switching transistor Output end connect with the luminescent device.

Optionally, the first switch transistor, the second switch transistor and the third switching transistor are p-type Transistor.

Optionally, the compensating module includes：4th switching transistor；Wherein, the input of the 4th switching transistor End is connect with first data signal end, the control terminal of the 4th switching transistor respectively with third scanning signal end Connected with the control terminal of the second switch transistor, the output end of the 4th switching transistor respectively with the charging module First input end is connected with the output end of the light emitting control module.

Optionally, the 4th transistor is P-type transistor.

Optionally, the light emitting control module includes：5th switching transistor；Wherein, the 5th switching transistor Input terminal connect connection, the control of the 5th switching transistor with the second end at the direct current signal end and the capacitance respectively End is connect with first scanning signal end, the output end of the 5th switching transistor respectively with the 4th switching transistor Output end connected with the input terminal of the driving transistor.

Optionally, the 5th switching transistor is P-type transistor.

A kind of organic EL display panel, including the pixel circuit.

A kind of display device, including the organic EL display panel.

Above-mentioned at least one technical solution that the embodiment of the present application uses can reach following advantageous effect：

Through the above technical solutions, the initialization module being arranged in pixel circuit, it can be in each drive cycle, all Processing is zeroed out to the driving current of luminescent device, avoids luminescent device after entering OFF state, due to still there is electric current residual Stay or discharge be not thorough caused by ghost, to, initialized by the driving current to luminescent device, ensure shine Device can thoroughly reach dark-state in time, avoid display ghost problem, display quality is promoted, moreover, the pixel circuit may be used also To realize circuit compensation function, ensure that driving current is uncorrelated to the threshold voltage of driving transistor device in charging module, Effectively promote show uniformity.

Description of the drawings

Attached drawing described herein is used for providing further understanding of the present application, constitutes part of this application, this Shen Illustrative embodiments and their description please do not constitute the improper restriction to the application for explaining the application.In the accompanying drawings：

Fig. 1 is a kind of one of structural schematic diagram of pixel circuit provided by the present application；

Fig. 2 is a kind of second structural representation of pixel circuit provided by the present application；

Fig. 3 is the timing control figure provided by the present application using Fig. 2 pixel circuits as foundation；

Fig. 4 (a) is operating diagram of the pixel circuit provided by the present application in initial phase；

Fig. 4 (b) is operating diagram of the pixel circuit provided by the present application in charging compensated stage；

Fig. 4 (c) is operating diagram of the pixel circuit provided by the present application in glow phase；

Fig. 5 is the emulation schematic diagram simulated with the input voltage of the application pixel circuit.

Specific implementation mode

To keep the purpose, technical scheme and advantage of the application clearer, below in conjunction with the application specific embodiment and Technical scheme is clearly and completely described in corresponding attached drawing.Obviously, described embodiment is only the application one Section Example, instead of all the embodiments.Based on the embodiment in the application, those of ordinary skill in the art are not doing Go out the every other embodiment obtained under the premise of creative work, shall fall in the protection scope of this application.

Below in conjunction with attached drawing, the technical solution that each embodiment of the application provides is described in detail.

It is a kind of structural schematic diagram of pixel circuit provided by the present application shown in referring to Fig.1, which includes mainly With lower module：Luminescent device D1, initialization module 1, charging module 2, compensating module 3, light emitting control module 4；Wherein：

The first input end 1a of the initialization module 1 respectively with the first data signal end Data and the compensating module 3 First input end 3a connections, the second input terminal 1b of the initialization module 1 connect with the second scanning signal end S2, it is described just Second input terminal 3bs of the third input terminal 1c of beginningization module 1 respectively with third scanning signal end S3 and the compensating module 3 connects It connecing, the 4th input terminal 1d of the initialization module 1 is connect with the 4th scanning signal end S4, and the 5th of the initialization module 1 the Input terminal 1e is connect with the output end 2c with the charging module 2, output end 1f and the photophore of the initialization module 1 The anode of part connects, and the cathode of shown luminescent device is connect with the second data signal end SS；

The first input end 2a of the charging module 2 respectively with the output end 3c of the compensating module 3 and the luminous control The output end 4c connections of molding block 4, the second input terminal 2b of the charging module 2 are connect with direct current signal end DD；

The first input end 4b of the light emitting control module 4 is connect with the first scanning signal end S1, the light emitting control mould Second input terminal 4a of block 4 is connect with the direct current signal end DD；

It is counted at first scanning signal end S1, third scanning signal end S3, the 4th scanning signal end 4 and first Under control according to signal end Data, the initialization module 1 respectively carries out just the charging module 2 and the luminescent device D1 Beginningization；Under the control of third scanning signal end S3 and the first data signal end Data, pass through the compensating module 3 It charges to the charging module 2；Under the control of the direct current signal end DD, the light emitting control module 4 controls described Charging module 2 drives the luminescent device D1 to shine.

In the specific implementation, the luminescent device D1 in the above-mentioned pixel circuit involved by the application is generally organic light emission two Pole pipe (OLED).Luminescent device D1 realizes luminescence display under the action of the saturation current of driving transistor DT.

The operation principle of above-mentioned pixel circuit is simply introduced below.

Specifically, the pixel circuit involved by Fig. 1 may include following working stage：

First stage：Initial phase.

At this stage, initialization module 1 is realized using the signal source of the first data signal end Data to luminescent device D1 Anode initialization, i.e., by the anode voltage of luminescent device D1 reset or apply negative pressure.Specifically, the second scanning signal end S2, third scanning signal end S3, the 4th scanning signal end S4 co- controllings initialization module 1 are in the conduction state, in turn, conducting Initialization module 1 can be that zero signal source of the first data signal end Data is input to luminescent device D1 by voltage signal, To which a luminescent device D1 upper work periods remaining current signal be reset so that luminescent device D1 reaches enough dark-state, Avoid signal remain or eliminate it is relatively slow caused by ghost problem, promote display quality.

Second stage：Charge compensated stage.

At this stage, compensating module 3 is realized using the signal source of the first data signal end Data to charging module 2 Charging.Specifically, third scanning signal end S3 controls the initialization that compensating module 3 is in the conduction state, and initial phase applies Signal source can control the conducting of charging module 2, and in turn, the compensating module 3 of conducting can will have certain offset voltage (compensation electricity Pressure be positive value) the first data signal end Data signal source input charging module 2, to, charge to charging module 2.

Phase III：Glow phase.

At this stage, light emitting control module 4 utilizes the direct current signal of direct current signal end DD, the control driving hair of charging module 2 Optical device D1 shines.Specifically, the first scanning signal end S1 and direct current signal end DD control light emitting controls module 4 is on shape State, the part of devices that the 4th scanning signal end S4 controls initialization module 1 is in the conduction state, and after charging compensates, it fills Electric module 2 is in saturation state.Direct current signal is input to luminescent device by the light emitting control module 4 of conducting by charging module 2 The anode of D1, the minus earth of luminescent device D1, in this manner it is possible to which luminescent device D1 is driven to shine.

Through the above technical solutions, the initialization module being arranged in pixel circuit, it can be in each drive cycle, all Processing is zeroed out to the driving current of luminescent device, avoids luminescent device after entering OFF state, due to still there is electric current residual Stay or discharge be not thorough caused by ghost, to, initialized by the driving current to luminescent device, ensure shine Device can thoroughly reach dark-state in time, avoid display ghost problem, display quality is promoted, moreover, the pixel circuit may be used also To realize circuit compensation function, ensure that driving current is uncorrelated to the threshold voltage of driving transistor device in charging module, Effectively promote show uniformity.

It should be noted that the driving transistor and switching transistor involved by the application can be thin film transistor (TFT)s (TFT, Thin Film Transistor) can also be metal oxide semiconductor field effect tube (MOS, Metal Oxide Semiconductor), do not limit herein.In specific implementation, the source electrode and drain electrode of these transistors can be interchanged, and not do It is specific to distinguish.It is said so that driving transistor and switching transistor are all thin film transistor (TFT) as an example when describing specific embodiment It is bright, and carried out with the input terminal of thin film transistor (TFT) (source electrode or drain electrode), output end (correspondingly drain electrode or source electrode) and control terminal Description.

A kind of achievable scheme, in the image element circuit structure of the application, with reference to shown in 1, in the pixel electricity of the application Lu Zhong, the charging module 2 can specifically include：Driving transistor DT and capacitance C；The input terminal of the driving transistor DT is The first input end of charging module 2, respectively with the output end of the output end of the compensating module 3 and the light emitting control module 4 Connection, the control terminal of the driving transistor DT respectively with the first end of the capacitance C, the first switch transistor T1 it is defeated Outlet is connected with the input terminal of the second switch transistor T2, and the output end of the driving transistor DT is respectively with described second The output end of switching transistor T2 is the output end of the charging module 2, is connect with the input terminal of the third switching transistor T3； The second end of the capacitance C is connect with the first input end at the direct current signal end and the light emitting control module 4 respectively.

Optionally, the driving transistor DT is P-type transistor in this application.Due to the threshold voltage of P-type transistor Vth is negative value, in order to ensure that driving transistor DT can be worked normally, when being initialized to luminescent device D1, is applied The signal source of first data signal end Data is generally zero or negative value.In this application, the first data signal end Data Signal source can be adjusted according to the functional requirement of different phase.

When the concrete structure of charging module 2 is driving transistor DT and capacitance C, the operation principle summary of the charging module For：In initial phase, driving transistor DT shutdowns, and initialization module 1 is connected, and is carried out to the control terminal of driving transistor DT Voltage clearing is handled, and in turn, the voltage of the first end for the capacitance C being connect with the control terminal of driving transistor DT is also cleared, and is made The capacitance for obtaining storage capacitance, that is, capacitance C is reset.In charging compensated stage, driving transistor DT conductings, and initialization module 1 closes Disconnected, compensating module 3 is connected, the first data signal end Data output offset voltages V_DataTo driving transistor DT control terminal (i.e. Charge for capacitance C), until the voltage of the control terminal of driving transistor DT is V_Data-V_th.In glow phase, crystal is driven Pipe DT is in saturation state, by driving transistor DT, will be input to by the direct current signal of the control output of light emitting control module 4 Luminescent device D1, drives its light emission and lights.

Based on any of the above-described scheme, shown in Fig. 1, the initialization module 1 can specifically include：First switch is brilliant Body pipe T1, second switch transistor T2 and third switching transistor T3；The input terminal of the first switch transistor T1 respectively with The first data signal end Data is connected with the input terminal of the compensating module 3, the control of the first switch transistor T1 End is connect with second scanning signal end S2, and the output end of the first switch transistor T1 is brilliant with the second switch respectively The control terminal connection of the input terminal, driving transistor DT of body pipe T2；The control terminal of the second switch transistor T2 respectively with institute It states third scanning signal end S3 to connect with the second input terminal of the compensating module 3, the output of the second switch transistor T2 End is connect with the output end of the input terminal of the third switching transistor T3 and driving transistor DT respectively；The third switch is brilliant The control terminal of body pipe T3 is connect with the 4th scanning signal end S4, output end and the hair of the third switching transistor T3 Optical device D1 connections.

Optionally, in this application, the first switch transistor T1, the second switch transistor T2 and the third Switching transistor T3 is P-type transistor simultaneously.And as the second scanning signal end S2, third scanning signal end S3 and the 4th scanning letter Number end S4 signal simultaneously for low level when, first switch transistor T1, the second switch transistor T2 and the third are opened It closes transistor T3 to simultaneously turn on, in this way, the initialization module 1 can work.

In fact, in this application, initialization module 1 be (first switch transistor T1, the second switch transistor T2 and The third switching transistor T3), the initialization to luminescent device D1 is not only realized, it can also be to the electricity in charging module 2 The capacitance for holding C is initialized, to avoid influence of the residual capacity to driving transistor DT.

When the concrete structure of initialization module 1 is first switch transistor T1, the second switch transistor T2 and described When third switching transistor T3, the operation principle summary of the initialization module 1 is：In initial phase, first switch transistor T1, the second switch transistor T2 and third switching transistor T3 conductings, on the one hand, will be by the first data signal end The reset signal of Data is transferred to luminescent device D1, drives it electric current zero setting, on the other hand, will be by the first data signal end The reset signal of Data is transferred to the control terminal of driving transistor DT so that the capacitance of capacitance C (storage capacitance) is zero.It is charging Compensated stage, first switch transistor T1 and third switching transistor T3 shutdowns, the second switch transistor T2 conductings, In fact, second switch transistor T2 does not work, but since second switch transistor T2 and the input terminal of compensating module 3 are same For third scanning signal end S3.In glow phase, first switch transistor T1 and second switch transistor T2 shutdowns, third Switching transistor T3 conductings, in order to which driving current can enter luminescent device D1 by third switching transistor.

In the pixel circuit of the application, shown in Fig. 1, the compensating module 3 can specifically include：4th switch Transistor T4；The input terminal of the 4th switching transistor T4 is connect with the first data signal end Data, and the described 4th opens The control terminal for closing transistor T4 connects with the control terminal of third scanning signal end S3 and the second switch transistor T2 respectively Connect, the output end of the 4th switching transistor T4 respectively with the input terminal of the driving transistor DT and the light emitting control mould The output end of block 4 connects.Optionally, in this application, the 4th switching transistor T4 is P-type transistor.

In the pixel circuit of the application, shown referring to Fig.1, the light emitting control module 4 can specifically include：5th opens Close transistor T5；The input terminal of the 5th switching transistor T5 respectively with the direct current signal end DD and capacitance C The connection connection of two ends, the control terminal of the 5th switching transistor T5 are connect with first scanning signal end S1, and the described 5th The output end of switching transistor T5 connects with the input terminal of the output end of the compensating module 3 and the driving transistor DT respectively It connects.Optionally, the 5th switching transistor T5 is P-type transistor.

It should be noted that the driving transistor and switching transistor mentioned in involved pixel circuit in this application It can all be designed using P-type transistor, the fabrication processing of pixel circuit can be simplified in this way.

Below by above-mentioned pixel circuit driving transistor and all P-type transistors of switching transistor for pixel The operation principle of circuit is described in detail.Wherein Fig. 2 is the concrete structure schematic diagram of pixel circuit, and Fig. 3 is corresponding electricity Road working timing figure.

Initial phase：

With reference to shown in Fig. 4 (a), in this stage, which realizes the anode to luminescent device D1, capacitance C Initialization, i.e., by the anode voltage zero setting of luminescent device D1, by the first terminal voltage zero setting of capacitance C.Second scanning signal end S2 Input low level, the T1 conductings of first switch transistor；Third scanning signal end S3 input low levels, second switch transistor T2 are led It is logical, the 4th switching transistor T4 conductings；4th scanning signal end S4 input low levels, the T3 conductings of third switching transistor；First Scanning signal end S1 input high levels, the 5th switching transistor T5 shutdowns；The reset signal of first data signal end Data inputs The first end of capacitance C is inputed to by first switch transistor T1；Meanwhile first data signal end Data input no-voltage it is logical The anode that first switch transistor T1 → second switch transistor T2 → third switching transistor T3 inputs to luminescent device D1 is crossed, I.e. the anode voltage of luminescent device D1 is also cleared signal initialization.To pass through first switch transistor T1, second switch The synergistic effect of transistor T2 and third switching transistor T3 realize to the anode voltage of luminescent device D1 and capacitance C The zero-setting operation of one terminal voltage avoided ghost problem in this way, can both ensure that luminescent device D1 can complete to realize dark-state；And And influence of the remaining storage capacitance to driving transistor can also be avoided.

Charge compensated stage：

With reference to shown in Fig. 4 (b), at this stage, pixel circuit realizes the charging compensating operation to capacitance C.Specifically, second Scanning signal end S2 input high levels, the T1 shutdowns of first switch transistor；Third scanning signal end S3 input low levels, second opens Close transistor T2 conductings, the 4th switching transistor T4 conductings；4th scanning signal end S4 input high levels, third switching transistor T3 is turned off；First scanning signal end S1 input high levels, the 5th switching transistor T5 shutdowns；At this point, being the first data signal end Data input offset voltages V_Data(offset voltage is positive value), which flows through the control terminal of driving transistor DT to electricity Hold C to charge, until the control terminal voltage of driving transistor DT is V_Data-|V_th|.Further, since third switching transistor T3 It disconnects, so that the electric current of driving transistor DT will not reduce luminescent device D1 indirectly and use the longevity by luminescent device D1 The loss of life.

Glow phase：

With reference to shown in Fig. 4 (c), at this stage, pixel circuit realizes the driving current driving hair by driving transistor DT Operation luminous optical device D1.Specifically, the second scanning signal end S2 input high levels, the T1 shutdowns of first switch transistor；The Three scanning signal end S3 input high levels, the T2 shutdowns of second switch transistor, the 4th switching transistor T4 shutdowns；4th scanning letter Number end S4 input low levels, third switching transistor T3 conducting；First scanning signal end S1 input low levels, the 5th switch crystal Pipe T5 conductings；In this way, the direct current signal V of direct current signal end DD inputs_DDThe driving transistor DT in saturation state can be flowed through, It third switching transistor T3 will be driven current through is input to luminescent device D1 and drives its light emission and light.Wherein, by driving The saturation capacitance formula of transistor DT calculates the operating current that can obtain flowing into luminescent device D1：

I_OLED=K [V_DD-(V_Data-|V_th|)-|V_th|]²=K (V_DD-V_Data)²

Wherein, it is dielectric constant that K, which is μ W/2L, μ, and W is the channel width of driving transistor DT, and L is driving transistor DT's Channel length.It can be seen that the operating current I of luminescent device D1_OLEDIt has been not driven the threshold voltage V of transistor DT_thShadow It rings, only the signal voltage V with the input of direct current signal end_DataAnd first data signal end Data input V_DataIt is related, thoroughly solve It has determined since driving transistor DT is due to threshold voltage V caused by manufacturing process and prolonged operation_thDrift, influences to shine The operating current I of device D1_OLED, ensure that the normal work of luminescent device D1.

In order to further illustrate the effect of application scheme, following emulation schematic diagram can refer to, wherein Fig. 5 is with this Shen The V of the first data signal end please_DataAnd the first S1 signal at scanning signal end, the S2 signals at the second scanning signal end, The S3 signals at three scanning signal ends and the S4 signals at the 4th scanning signal end, which are used as, to be inputted, and the V simulated_OLEDZero setting show It is intended to, in fact, V_OLEDI can be converted to_OLED, effect is similar.Wherein, in the initial phase in each period, in V_Data、S1、 Under the control of S2, S3 and S4, V can be made_OLEDZero setting (V in the application_OLEDRefer to luminescent device D1 anode and cathode it Between voltage difference), and anode voltage in the prior art at this stage probably -1.3V, the anode voltage of the application at this stage Probably -3v or so, if the voltage V of the second data signal end SS_SSIt is -3V, then there are two sections of pressure differences of luminescent device D1 for prior art It is positive, there are still certain voltage residuals, and causing luminescent device to shine, there may be ghosts, and the application can to shine The voltage of device becomes very low even 0, to ensure that dark-state can be fully achieved in luminescent device D1, avoid ghost problem, carry Rise display quality.

Meanwhile present invention also provides a kind of organic electroluminescence panel, which includes above-mentioned Pixel circuit involved by one embodiment.The principle solved the problems, such as due to the organic EL display panel and a kind of aforementioned picture Plain circuit is similar, therefore the implementation of the organic EL display panel may refer to the implementation of pixel circuit, repeats place not It repeats again

Present invention also provides a kind of display device, which includes mainly having involved by any of the above-described embodiment Organic electro luminescent panel.The display device can be display, mobile phone, TV, notebook, all-in-one machine, VR equipment or AR equipment Equal wearable devices, other essential component parts for display device are that those skilled in the art should What understanding had, this will not be repeated here, also should not be taken as limiting the invention.

Above is only an example of the present application, it is not intended to limit this application.For those skilled in the art For, the application can have various modifications and variations.It is all within spirit herein and principle made by any modification, equivalent Replace, improve etc., it should be included within the scope of claims hereof.