CN203931451U - Image element circuit and display device - Google Patents

Abstract

The utility model provides a kind of image element circuit and display device.Described image element circuit, comprises multirow pixel cell, and every a line pixel cell comprises a plurality of sub-pixel unit; Each sub-pixel unit comprises sub-pixel driving circuit and light-emitting component, and every a line pixel cell also comprises row sharing unit; A plurality of sub-pixel unit are all connected with secondary signal line with first signal line; Each sub-pixel unit that this row sharing unit comprises with this row pixel cell is connected with secondary signal line by first signal line, to have valve value compensation function.Fundamental purpose of the present utility model is to provide a kind of image element circuit and display device, and the utility model increases the aperture opening ratio of pixel, when obtaining evenly demonstration, reduces the current density of organic luminous layer.

Description

Pixel circuit and display device

technical field

The utility model relates to the field of display technology, in particular to a pixel circuit and a display device.

Background technique

The basic AMOLED (Active Matrix/Organic Light Emitting Diode, active matrix organic light emitting diode) pixel driving circuit is a 2T1C pixel driving circuit with a simple structure. However, based on LTPS (Low Temperature Poly-silicon, low-temperature polysilicon technology) AMOLED pixel drive circuit, due to LTPS has problems such as poor threshold voltage uniformity, it is necessary to increase the driving TFT (Thin Film Transistor, Thin Film Field Effect Transistor) in the AMOLED pixel design. ) Threshold voltage compensation circuit. Common designs of AMOLED pixel driver circuits with threshold voltage compensation require 6T1C pixel driver circuits or 5T2C pixel driver circuits, or require more TFTs and/or capacitors. The increase in the number of TFTs and/or capacitors will occupy a large layout space, which is not conducive to the reduction of the size of AMOLED pixels, which limits the development of AMOLED pixel drive circuits with high PPI (Pixel Per Inch, the number of pixels per inch). .

Utility model content

The main purpose of the utility model is to provide a pixel circuit and a display device, which can increase the aperture ratio of the pixel, thereby reducing the current density of the organic light-emitting layer while obtaining uniform display.

In order to achieve the above object, the utility model provides a pixel circuit, including multiple rows of pixel units, each row of pixel units includes a plurality of sub-pixel units; each of the sub-pixel units includes a sub-pixel driving circuit and a light-emitting element, the sub-pixel The drive circuit includes a drive transistor connected to the light-emitting element and a drive control module respectively connected to a data line and the drive transistor; each row of pixel units also includes a row sharing unit;

The plurality of sub-pixel units are all connected to the first signal line and the second signal line;

The row sharing unit is connected to each sub-pixel unit included in the row of pixel units through the first signal line and the second signal line.

During implementation, the sub-pixel unit is arranged in the effective display area, and the row sharing unit is arranged outside the effective display area.

During implementation, the first pole of the driving transistor is connected to the first end of the light emitting element, the second pole is connected to the first signal line; the second end of the light emitting element is connected to the second signal line ;

The row sharing unit includes:

an initial module connected to the initial control signal and a lighting control module connected to the lighting control signal;

An initial module for accessing an initial control signal and setting the gate potential of the driving transistor to an initial level through the driving control module when the initial control signal and the scanning signal on the scanning line are simultaneously valid, and The first signal line is connected;

And, a lighting control module for accessing a lighting control signal, and controlling the first signal line to be connected to a first level and the second signal line to be connected to a second level when the lighting control signal is valid;

The drive control module includes: when the scan signal is valid, control the data voltage on the data line to be written into the drive transistor, and when the light emission control signal is valid, control the drive transistor to drive the light emission The driving control unit, which emits light and compensates the threshold of the driving transistor, is respectively connected with the gate of the driving transistor, the first pole of the driving transistor, the second pole of the driving transistor and the scanning line.

During implementation, the drive control unit includes a data writing transistor, a drive control transistor and a storage capacitor, wherein,

The gate of the data writing transistor is connected to the scanning line, the first pole is connected to the data line, and the second pole is connected to the first pole of the driving transistor;

The gate of the driving control transistor is connected to the scanning line, the first pole is connected to the gate of the driving transistor, and the second pole is connected to the second pole of the driving transistor;

The first end of the storage capacitor is connected to the first pole of the driving transistor, and the second end is connected to the gate of the driving transistor.

When implemented, the initial modules include:

Initialize the transistor, the gate is connected to the initial control signal, the first pole is connected to the second signal line, and the second pole is connected to the initial level.

During implementation, the lighting control module includes:

The first light-emitting control transistor, the gate of which is connected to the light-emitting control signal, the first electrode connected to the first level, and the second electrode connected to the first signal line;

The gate of the second light-emitting control transistor is connected to the light-emitting control signal, the first pole is connected to the second signal line, and the second pole is connected to the second level.

The utility model also provides a display device, which is characterized in that it comprises the above-mentioned pixel circuit.

Compared with the prior art, the pixel circuit described in the present invention adopts a row-sharing unit, so that the number of TFTs in the effective display area can be reduced while compensating the threshold value of the drive transistor, so that the aperture ratio of the pixel is increased, so that in the While displaying uniformly, the current density of the organic light-emitting layer is reduced, and the service life of the AMOLED panel is prolonged.

Description of drawings

FIG. 1 is a structural diagram of a pixel circuit described in an embodiment of the present invention;

2 is a structural block diagram of a sub-pixel unit and a row-sharing unit included in the pixel circuit according to an embodiment of the present invention;

3 is a circuit diagram of a sub-pixel unit and a row sharing unit included in the pixel circuit according to an embodiment of the present invention;

Fig. 4 is a working timing diagram including the sub-pixel unit and the row sharing unit as shown in Fig. 3;

FIG. 5 is a circuit diagram of the pixel circuit described in the embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. example. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

The transistors used in all embodiments of the present invention can be thin film transistors or field effect transistors or other devices with the same characteristics. In the embodiment of the present invention, in order to distinguish the two poles of the transistor except the gate, the first pole may be the source or the drain, and the second pole may be the drain or the source. In addition, transistors can be classified into n-type transistors or p-type transistors according to their characteristics. In the driving circuit provided by the embodiment of the present invention, all transistors are described by taking n-type transistors as an example. It can be easily imagined below, and therefore also within the scope of protection of the embodiments of the present utility model.

The pixel circuit described in the embodiment of the present invention includes a plurality of rows of pixel units, and each row of pixel units includes a plurality of sub-pixel units; each of the sub-pixel units includes a sub-pixel driving circuit and a light-emitting element, and the sub-pixel driving circuit includes and The driving transistor connected to the light-emitting element and the driving control module respectively connected to a data line and the driving transistor; each row of pixel units also includes a row sharing unit;

The plurality of sub-pixel units are all connected to the first signal line and the second signal line;

The row sharing unit is connected to each sub-pixel unit included in the row of pixel units through the first signal line and the second signal line, so as to have a threshold compensation function.

In the pixel circuit described in this embodiment of the present invention, the sub-pixel unit includes a light-emitting element in addition to the sub-pixel driving circuit. The sub-pixel driving circuit and the light-emitting element together form a sub-pixel unit. The light-emitting element can be, for example, OLED (Organic Light Emitting Diode).

The pixel circuit described in this embodiment of the present invention adopts a row sharing unit, so that the number of TFTs in the effective display area can be reduced while compensating the threshold value of the driving transistor, so that the aperture ratio of the pixel can be increased, so that the display can be uniform while , reduces the current density of the organic light-emitting layer, and prolongs the service life of the AMOLED panel.

Preferably, the sub-pixel unit is arranged in the effective display area, the row sharing unit is arranged outside the effective display area, and the common circuit in each row of pixel units is arranged outside the effective display area to further reduce the effective display area. The number of TFTs in the display area increases the aperture ratio.

Specifically, the pixel circuit described in the embodiment of the present invention includes m rows of pixel units, and each row of pixel units includes n sub-pixel units; the n sub-pixel units included in the j-th row of pixel units are all connected to the j-th scanning line (Fig. 1); the kth sub-pixel unit included in each row of pixel units is connected to the kth data line; m and n are integers greater than 1, j is a positive integer less than or equal to m, and k is less than or equal to n a positive integer;

As shown in Figure 1, Vdata_1 is the data voltage output by the first data line, Vdata_k-1 is the data voltage output by the k-1th data line, Vdata_k is the data voltage output by the kth data line, and Vdata_k+1 is the data voltage output by the data line Data voltage, Vdata_n is the data voltage output by the nth data line;

Each of the sub-pixel units includes a sub-pixel driving circuit and a light-emitting element, and the sub-pixel driving circuit includes a driving transistor connected to the light-emitting element and a driving control module connected to a data line and the driving transistor;

Each row of pixel units also includes a row sharing unit; m row sharing units form a row sharing circuit;

A plurality of sub-pixel units included in each row of pixel circuits are connected to the first signal line and the second signal line;

The row sharing unit is connected to each sub-pixel unit included in the row of pixel units through the first signal line and the second signal line, so as to have a threshold compensation function;

The sub-pixel unit is arranged in the effective display area, and the row sharing unit is arranged outside the effective display area;

In Fig. 1, V1_1 is the first signal line of the pixel circuit in the first row, V2_1 is the second signal line of the pixel circuit in the first row, V1_j-1 is the first signal line of the pixel circuit in the j-1th row, V2_j- 1 is the second signal line of the pixel circuit in row j-1, V1_j is the first signal line of pixel circuit in row j, V2_j is the second signal line of pixel circuit in row j, V1_j+1 is row j+1 The first signal line of the pixel circuit, V2_j+1 is the second signal line of the pixel circuit in the j+1th row, V1_m is the first signal line of the pixel circuit in the mth row, and V2_m is the second signal line of the pixel circuit in the mth row .

Preferably, the first pole of the driving transistor is connected to the first end of the light emitting element, the second pole is connected to the first signal line; the second end of the light emitting element is connected to the second signal line ;

The row sharing unit includes:

an initial module connected to the initial control signal and a lighting control module connected to the lighting control signal;

An initial module for accessing an initial control signal and setting the gate potential of the driving transistor to an initial level through the driving control module when the initial control signal and the scanning signal on the scanning line are simultaneously valid, and The first signal line is connected;

And, a lighting control module for accessing a lighting control signal, and controlling the first signal line to be connected to a first level and the second signal line to be connected to a second level when the lighting control signal is valid;

The drive control module includes: when the scan signal is valid, control the data voltage on the data line to be written into the drive transistor, and when the light emission control signal is valid, control the drive transistor to drive the light emission The driving control unit, which emits light and compensates the threshold of the driving transistor, is respectively connected with the gate of the driving transistor, the first pole of the driving transistor, the second pole of the driving transistor and the scanning line.

Preferably, the drive control unit includes a data writing transistor, a drive control transistor and a storage capacitor, wherein,

The gate of the data writing transistor is connected to the scanning line, the first pole is connected to the data line, and the second pole is connected to the first pole of the driving transistor;

The gate of the driving control transistor is connected to the scanning line, the first pole is connected to the gate of the driving transistor, and the second pole is connected to the second pole of the driving transistor;

The first end of the storage capacitor is connected to the first pole of the driving transistor, and the second end is connected to the gate of the driving transistor.

Preferably, the initial module includes:

Initialize the transistor, the gate is connected to the initial control signal, the first pole is connected to the second signal line, and the second pole is connected to the initial level.

Preferably, the lighting control module includes:

The first light-emitting control transistor, the gate of which is connected to the light-emitting control signal, the first electrode connected to the first level, and the second electrode connected to the first signal line;

The gate of the second light-emitting control transistor is connected to the light-emitting control signal, the first pole is connected to the second signal line, and the second pole is connected to the second level.

Specifically, the connection between a sub-pixel unit and a row sharing unit is taken as an example to illustrate as follows:

As shown in FIG. 2, the sub-pixel unit includes a sub-pixel driving circuit and an organic light emitting diode OLED, and the sub-pixel driving circuit includes a driving transistor DTFT connected to the OLED and a data line Data and a gate of the driving transistor DTFT respectively. 1. A drive control module 21 connected to the first pole of the drive transistor DTFT and the second pole of the drive transistor DTFT;

The drive transistor DTFT has a first pole connected to the anode of the OLED, and a second pole connected to the first signal line V1;

The cathode of the OLED is connected to the second signal line V2;

The drive control module 21 also accesses a scan signal Vscan on a scan line;

The row sharing unit includes an initial module 22 connected to the initial control signal CN and a light emission control module 23 connected to the light emission control signal EM;

The initial module 22 is connected to the first signal line V1, and is used to drive the driving transistor through the driving control module 21 when the initial control signal CN and the scanning signal Vscan on the scanning line are valid at the same time. The gate potential of the DTFT is set to the initial level VINI;

The light emission control module 23 is configured to control the first signal line V1 to connect to the high level VDD and the second signal line V2 to connect to the low level VSS when the light emission control signal CN is valid, that is, the first level is a high level VDD, and the second level is a low level VSS;

The driving control module 21 is configured to control the data voltage Vdata on the data line to be written into the driving transistor DTFT when the scanning signal Vscan is valid, and control the driving transistor when the light emission control signal EM is valid The DTFT drives the OLED to emit light and compensates the threshold of the drive transistor DTFT.

Specifically, as shown in FIG. 3, the drive control module may include a data writing transistor TI, a drive control transistor TC, and a storage capacitor Cs, wherein,

The data writing transistor TI, the gate is connected to the scanning signal Vscan, the first pole is connected to the data voltage Vdata on the data line, and the second pole is connected to the first pole of the driving transistor DTFT;

The gate of the drive control transistor DTFT is connected to the scan signal Vscan, the first pole is connected to the gate of the drive transistor DTFT, and the second pole is connected to the second pole of the drive transistor DTFT;

The first end of the storage capacitor Cs is connected to the first pole of the driving transistor DTFT, and the second end is connected to the gate of the driving transistor DTFT;

The initial modules include:

Initializing the transistor TINI, the gate is connected to the initial control signal CN, the first pole is connected to the second signal line V2, and the second pole is connected to the initial level VINI;

The lighting control module includes:

The gate of the first light emission control transistor TEC1 is connected to the light emission control signal EM, the first pole is connected to the high level VDD, and the second pole is connected to the first signal line V1;

The gate of the second light emission control transistor TEC2 is connected to the light emission control signal EM, the first pole is connected to the second signal line V2, and the second pole is connected to the low level VSS;

DTFT, TI, TC, TINI, TEC1 and TEC2 are all n-type TFTs.

In the embodiment shown in Figure 3, the sub-pixel units including DTFT, TI, TC, Cs and OLED are arranged in the effective display area, and the row sharing units including TEC1, TEC2 and TINI are arranged outside the effective display area, and Multiple sub-pixel units of the same row of pixel units are all connected to the row-sharing unit to have a threshold compensation function.

In actual implementation, it is not limited to the above embodiments, and the purpose of reducing the TFTs in the effective display area can be achieved only by using the row sharing unit, which can reduce the pixel size.

The operation sequence of the embodiment shown in Figure 3 is shown in Figure 4 (Vdata is the data voltage, which represents the information of the image, the output voltage is related to the image to be displayed, the image is uncertain, and the data is also uncertain, so The output level of Vdata is represented by lattice filling), which is divided into three stages:

Phase A (initialization phase): Vscan and CN are high, EM is low, TI, TC and TINI are on, TEC1 and TEC2 are off, Vdata is written through TI, the voltage on V1 is VINI, and the voltage on V2 is The voltage is a floating voltage, the drain (second pole) of the DTFT is connected to the gate of the DTFT, and the gate potential of the DTFT is the initialization level VINI, and the source (first pole) potential of the DTFT is Vdata;

Phase B (compensation phase): Vscan is high level, CN and EM are low level, TI and TC are turned on, TINI, TEC1 and TEC2 are turned off, the drain (second pole) of DTFT is connected to the gate of DTFT, The source (first pole) of the DTFT is connected to Vdata, the DTFT forms a diode connection, and the gate potential of the DTFT is discharged from the initialization level VINI to Vdata+Vth (Vth is the threshold of the DTFT), that is, the potential of the second end of Cs is Vdata +Vth, and at this time the voltage on V1 is Vdata+Vth, and the voltage on V2 is the floating voltage;

In stage C (light-emitting stage), Vscan and CN are low level, EM is high level, that is, TI, TC and TINI are cut off, TEC1 and TEC2 are turned on, the voltage on V1 becomes high level VDD, and V2 is controlled by the upper The voltage changes from the floating voltage to the low level VSS, and the gate potential of the DTFT is maintained at Vdata+Vth by the storage capacitor Cs (because the second terminal of Cs is floating at this time, the discharge path of Cs is turned off, so Cs The potential of the second terminal of the DTFT, that is, the gate potential of the DTFT is held by Cs), and the source (first pole) potential of the DTFT is VSS at this time, so the source-drain current I _DS flowing through the DTFT =K×(V _data +Vth- VSS-Vth) ² =K×(V _data -VSS) ² , K is a constant related to the process and design, then the final driving current of the OLED has nothing to do with the threshold voltage of the DTFT, but is only related to Vdata.

Fig. 5 is a circuit diagram of a pixel circuit applying the sub-pixel unit and the row sharing unit shown in Fig. 3. It can be seen from Fig. 5 that each row of pixel units shares the row sharing unit on the left, and m row sharing units form a row sharing circuit. The initial control signal of the row sharing unit of the pixel circuit in the first row is CN_1, the scanning signal Vscan_1, and the light emission control signal EM_1, and the initial control signal of the row sharing unit of the pixel circuit in the jth row is CN_j, the scanning signal Vscan_j, and the light emission control signal EM_j, The initial control signal of the row-sharing unit of the j+1-th row of pixel circuits is CN_j+1, the scanning signal Vscan_j+1, and the light emission control signal EM_j+1; the initial control signal of the row-sharing unit of the m-th row of pixel circuits is CN_m, scanning Signal Vscan_m, light emission control signal EM_m, wherein j is a positive integer less than or equal to m.

The display device described in the embodiment of the present invention includes the above-mentioned pixel circuit. The display device may include a liquid crystal display device, such as a liquid crystal panel, a liquid crystal television, a mobile phone, and a liquid crystal display. In addition to the liquid crystal display device, the display device may also include an organic light emitting display or other types of display devices, such as an electronic reader.

The above description is only illustrative of the present utility model, rather than restrictive. Those of ordinary skill in the art understand that many modifications, changes, or Equivalent, but all will fall within the protection scope of the present utility model.

Claims (7)

1. an image element circuit, comprises multirow pixel cell, and every a line pixel cell comprises a plurality of sub-pixel unit; Described in each, sub-pixel unit comprises sub-pixel driving circuit and light-emitting component, and this sub-pixel driving circuit comprises the driving transistors being connected with described light-emitting component and the drive control module being connected with this driving transistors with a data line respectively; It is characterized in that, every a line pixel cell also comprises row sharing unit;

Described a plurality of sub-pixel unit is all connected with secondary signal line with first signal line;

Each sub-pixel unit that described row sharing unit comprises with this row pixel cell is connected with described secondary signal line by described first signal line.

2. image element circuit as claimed in claim 1, is characterized in that,

Described sub-pixel unit is arranged in effective display area, and described row sharing unit is arranged at outside effective display area.

3. image element circuit as claimed in claim 1, is characterized in that,

Described driving transistors, first utmost point is connected with the first end of described light-emitting component, and second utmost point is connected with described first signal line; The second end of described light-emitting component is connected with described secondary signal line;

Described row sharing unit comprises:

The light emitting control module of the initial module of access initial control signal and access LED control signal;

Be used for accessing initial control signal, and the sweep signal on described initial control signal and sweep trace is set to the initial module of original levels simultaneously effectively time by the grid potential of the described driving transistors of described drive control module, be connected with described first signal line;

And, for accessing LED control signal, and when described LED control signal is effective, control the light emitting control module that described first signal line accesses the first level described secondary signal line access second electrical level;

Described drive control module comprises: for when described sweep signal is effective, the data voltage of controlling on described data line writes described driving transistors, when described LED control signal is effective, control described driving transistors and drive described light-emitting component luminous and compensate the driving control unit of the threshold value of this driving transistors, be connected with described sweep trace with the grid of this driving transistors, second utmost point of first utmost point of this driving transistors, this driving transistors respectively.

4. image element circuit as claimed in claim 3, is characterized in that, described driving control unit comprises that data write transistor, drive control transistor and memory capacitance, wherein,

Described data write transistor, and grid is connected with described sweep trace, and first utmost point is connected with described data line, and second utmost point is connected with first utmost point of described driving transistors;

Described drive control transistor, grid is connected with described sweep trace, and first utmost point is connected with the grid of described driving transistors, and second utmost point is connected with second utmost point of described driving transistors;

Described memory capacitance, first end is connected with first utmost point of described driving transistors, and the second end is connected with the grid of described driving transistors.

5. image element circuit as claimed in claim 4, is characterized in that, described initial module comprises:

Initialization transistor, grid accesses described initial control signal, and first utmost point is connected with described secondary signal line, the second utmost point access original levels.

6. image element circuit as claimed in claim 5, is characterized in that, described light emitting control module comprises:

The first light emitting control transistor, grid accesses described LED control signal, and first utmost point accesses the first level, and second utmost point is connected with described first signal line;

The second light emitting control transistor, grid accesses described LED control signal, and first utmost point is connected with described secondary signal line, and second utmost point accesses described second electrical level.

7. a display device, is characterized in that, comprises the image element circuit as described in arbitrary claim in claim 1 to 6.