This application claims the benefit of priority to Chinese Patent Application No. 201410283835.2, filed with the Chinese Patent Office on Jun. 23, 2014 and entitled “ORGANIC LIGHT EMITTING DIODE PIXEL COMPENSATION CIRCUIT, AND DISPLAY PANEL DEVICE CONTAINING THE SAME”, the content of which is incorporated herein by reference in its entirety.
At present, as shown in
In the signal write-in stage, in the case that a scan signal Scan is at high-level, the transistor T12 is switched on, a data signal Data is input to a gate electrode of the transistor T11 through the transistor T12, hence the transistor T11 is switched on and a capacitor C11 is charged.
In the light emitting stage, the scan signal Scan is made to be at low-level, the transistor T12 is switched off, the capacitor C11 is discharged to enable the transistor T11 to be still on. A power supply voltage PVDD keep providing the OLED with a voltage until a next stage arrives. The above cycle is then repeated.
However, due to a limitation of a process level, during a process of manufacturing a transistor circuit of an OLED display, a drive current of the OLED display often deviates and a panel often displays abnormally due to a threshold voltage existed in a driving transistor.
In view of the above, the present disclosure provides an organic light emitting diode (OLED) pixel compensation circuit, and a display panel and a display device which contain the circuit.
An OLED pixel compensation circuit according to an embodiment of the present disclosure is for driving the OLED to emit light. The OLED pixel compensation circuit comprises a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor and a storage capacitor. Specifically, a gate electrode of the first transistor is coupled to a scan signal, a first electrode of the first transistor is coupled to a data signal, and a second electrode of the first transistor is coupled to a gate electrode of the fifth transistor. A gate electrode of the second transistor is coupled to the scan signal, a first electrode of the second transistor is coupled to a power supply voltage, and a second electrode of the second transistor is coupled to a second electrode of the storage capacitor. A gate electrode of the third transistor is coupled to a first light emitting signal, a first electrode of the third transistor is coupled to the power supply voltage, and a second electrode of the third transistor is coupled to a first electrode of the fifth transistor. A gate electrode of the fourth transistor is coupled to the scan signal, a first electrode of the fourth transistor is coupled to the gate electrode of the fifth transistor, and a second electrode of the fourth transistor is coupled to the first electrode of the fifth transistor. A second electrode of the fifth transistor is coupled to a first electrode of the seventh transistor. A gate electrode of the sixth transistor is coupled to the first light emitting signal, a first electrode of the sixth transistor is coupled to the gate electrode of the fifth transistor, and a second electrode of the sixth transistor is coupled to the second electrode of the storage capacitor. A gate electrode of the seventh transistor is coupled to a second light emitting signal, and a second electrode of the seventh transistor is coupled to a first electrode of the OLED. A first electrode of the storage capacitor is coupled to the first electrode of the seventh transistor. And a second electrode of the OLED is coupled to a low-level signal, and the OLED emits light in response to a drive current generated by the fifth transistor.
A display panel according to an embodiment of the present disclosure contains the above OLED pixel compensation circuit.
A display device according to an embodiment of the present disclosure contains the above OLED pixel compensation circuit or the above display panel.
a is an OLED pixel compensation circuit according to an embodiment of the present disclosure;
b is a timing diagram of an operation of the circuit shown in
a is an OLED pixel compensation circuit according to an embodiment of the present disclosure;
b is a timing diagram of an operation of the circuit shown in
a is an OLED pixel compensation circuit according to an embodiment of the present disclosure;
b is a timing diagram of an operation of the circuit shown in
a is an OLED pixel compensation circuit according to an embodiment of the present disclosure; and
b is a timing diagram of an operation of the circuit shown in
To make the above object, features and advantages of the present disclosure more obvious and easy to be understood, in the following, particular embodiments of the present disclosure will be illustrated in detail in conjunction with the drawings.
More specific details will be set forth in the following descriptions for sufficient understanding of the disclosure, however the disclosure can also be implemented by other ways different from the way described herein, and therefore the disclosure is not limited to particular embodiments disclosed hereinafter.
Reference is made to
Optionally, the first electrode of the OLED may be an anode of the OLED. The second electrode of the OLED may be a cathode of the OLED. And the “coupling” herein may be a direct connection or an indirect connection.
Specifically, the first transistor T1 is for transferring the data signal Data to the gate electrode of the fifth transistor T5 under the control of the scan signal Scan. The second transistor T2 is for transferring the power supply voltage PVDD to the second electrode of the storage capacitor Cst under the control of the scan signal Scan. The third transistor T3 is for transferring the power supply voltage PVDD received by the first electrode of the third transistor T3 to the second electrode of the third transistor T3, under the control of the first light emitting signal Emit1. The fourth transistor T4 is for transferring the data signal Data received by the first electrode of the fourth transistor T4 to the first electrode of the fifth transistor T5, under the control of the scan signal Scan. The fifth transistor T5 is for generating the drive current for driving the OLED to emit light. The sixth transistor T6 is for switching on the first and second electrodes of the sixth transistor T6 under the control of the first light emitting signal Emit1. The seventh transistor T7 is for making the drive current generated by the fifth transistor T5 drive the OLED to emit light. And the storage capacitor Cst is for storing a received voltage (a voltage received by the first electrode of the storage capacitor or a voltage received by the second electrode of the storage capacitor), and couple a change value of voltage on the second electrode of the storage capacitor to the first electrode of the storage capacitor or couple a change value of voltage on the first electrode of the storage capacitor to the second electrode of the storage capacitor.
In the following, a specific working process and a working principle are described. Referring to
Metal Oxide Semiconductor (NMOS) transistors. Therefore, the first electrode of the transistors may be a drain electrode and the second electrode of the transistors may be a source electrode. Driving the OLED pixel compensation circuit may comprise a first stage, a second stage and a third stage. And the first stage is a reset stage of the circuit, for initializing the circuit.
Specifically, in the first stage (denoted “I” in
The second stage (denoted “II” in
The third stage (denoted “III” in
It can be seen that, with the OLED pixel compensation circuit according to the present embodiment, an influence of the threshold voltage of the driving transistor (the fifth transistor T5) on the generated driving current may be counteracted and the threshold voltage of the driving transistor is compensated. Thereby the driving current generated by the driving transistor does not deviate, and an OLED panel tends to display normally.
Referring to
In the first stage I (reset stage), the scan signal Scan is a low-level signal, the first light emitting signal Emit1 is a low-level signal, a second light emitting signal Emit2 is a high-level signal and the data signal Data is a high-level signal.
In the second stage II (threshold compensation stage), the scan signal Scan is a low-level signal, the first light emitting signal Emit1 is a low-level signal, the second light emitting signal Emit2 is a low-level signal and the data signal Data is a high-level signal.
In the third stage III (light emitting stage), the scan signal Scan is a high-level signal, the first light emitting signal Emit1 is a high-level signal, the second light emitting signal Emit2 is a high-level signal. It should be noted that the data signal Data in this stage may be a high-level signal or a low-level signal.
A specific implementation process and a working principle in the present embodiment are similar to that in the embodiment as shown in
Referring to
In the first stage I (reset stage), the scan signal Scan is a high-level signal, the first light emitting signal Emit1 is a high-level signal, the second light emitting signal Emit2 is a high-level signal and the data signal Data is a high-level signal.
In the second stage II (threshold compensation stage), the scan signal Scan comprises a high-level signal, the first light emitting signal Emit1 is a high-level signal, the second light emitting signal Emit2 is a low-level signal and the data signal Data comprises a high-level signal.
In the third stage III (light emitting stage), the scan signal Scan is a low-level signal, the first light emitting signal Emit1 is a low-level signal and the second light emitting signal Emit2 is a high-level signal. It should be noted that, the data signal Data in this stage may be a high-level signal or a low-level signal.
A specific implementation process and a working principle in the present embodiment are similar to that in the embodiment as shown in
Referring to
In the first stage (reset stage), the scan signal Scan is a low-level signal, a first light emitting signal Emit1 is a high-level signal, the second light emitting signal Emit2 is a high-level signal and the data signal Data is a high-level signal.
In the second stage (threshold compensation stage), the scan signal Scan comprises a low-level signal, the first light emitting signal Emit1 is a high-level signal, the second light emitting signal Emit2 is a low-level signal and the data signal Data comprises a high-level signal.
In the third stage (light emitting stage), the scan signal is a high-level signal, the first light emitting signal Emit1 is a low-level signal and the second light emitting signal Emit2 is a high-level signal. It should be noted that, the data signal Data in this stage may be a high-level signal or a low-level signal.
A specific implementation process and a working principle in the present embodiment are similar to that in the embodiment as shown in
The OLED pixel compensation circuit according to any one of the embodiments as shown in
Furthermore, in all the above embodiments, the seventh transistor T7 is described by taking a NMOS transistor as example. However, in the case that the level of the second light emitting signal Emit2 is reversed, the seventh transistor T7 may be also replaced with a PMOS transistor.
The present disclosure further provides a display panel including the OLED pixel compensation circuit according to any one of the above embodiments.
The present disclosure further provides a display device including the OLED pixel compensation circuit according to any one of the above embodiments, or including the above display panel.
The display panel or display device is capable of counteracting the influence of the threshold voltage of the driving transistor (the fifth transistor T5) on the generated drive current and compensates the threshold voltage of the driving transistor, since it comprises the OLED pixel compensation circuit according to the above embodiments. So that the drive current generated by the driving transistor does not deviate and the OLED panel tends to display normally.
It should be noted that, the above embodiments may make reference to each other, and may be used in combination. Though the present disclosure is disclosed by way of preferred embodiments as described above, those embodiments are not intended to limit the present disclosure. By using the methods and the technical aspects disclosed above, possible variations and changes may be made to the technical scheme of the present disclosure by those skilled in the art without departing from the essential scope of the present disclosure. Therefore, any simple change, equivalent alternation and modification made to the above embodiments according to the technical principle of the present disclosure, which do not depart from the matters of the technical scheme of the present disclosure, all fall within the scope of protection of the technical scheme of the present disclosure.
Number | Date | Country | Kind |
---|---|---|---|
201410283835.2 | Jun 2014 | CN | national |