This application claims priority to Taiwan Application Serial Number 112130998, filed Aug. 17, 2023, which is herein incorporated by reference in its entirety.
The present invention relates to a display device. More particularly, the present invention relates to a display device including pixel circuits.
Nowadays, the narrow bezel and the high quality image are eagerly pursued in display techniques. In some cases, if the voltage maintained by the storage capacitor included in the pixel circuit is decreased due to the leakage in transistor, it may reduce the image quality. Therefore, how to improve the above problems and the increase in overall circuit area, in order to provide the narrow bezel display, are the important issues in this filed.
The present disclosure provides a display device. The display device includes a pixel circuit and a stage of a scan driver. The stage of the scan driver is electrically coupled to the pixel circuit. The stage of a scan driver is configured to output a first scan signal and a second scan signal to the pixel circuit. A first enable voltage of the first scan signal is at a first logic level. A first disable voltage of the first scan signal is at a second logic level. A second enable voltage of the second scan signal is at the second logic level.
The present disclosure provides a display device. The display device includes a pixel circuit and a stage of a scan driver. The pixel circuit includes a P-type transistor and a N-type transistor. The stage of the scan driver is electrically coupled to the pixel circuit. The stage of the scan driver is configured to perform the following steps. A first scan signal is output to a gate terminal of the P-type transistor. A second scan signal is output to a gate terminal of the N-type transistor. A first enable voltage of the first scan signal is at a first logic level. A first disable voltage of the first scan signal is at a second logic level. A second enable voltage of the second scan signal is at the second logic level.
Summary, the stage of the scan driver outputs two scan signals having different enable voltages to the pixel circuit, in order to control the operation of the pixel circuit.
The present disclosure can be more fully understood by reading the following detailed description of the embodiment, with reference made to the accompanying drawings as follows.
Reference will now be made in detail to embodiments of the present disclosure, examples of which are described herein and illustrated in the accompanying drawings. While the disclosure will be described in conjunction with embodiments, it will be understood that they are not intended to limit the disclosure to these embodiments. Description of the operation does not intend to limit the operation sequence. Any structures resulting from recombination of elements with equivalent effects are within the scope of the present disclosure. It is noted that, in accordance with the standard practice in the industry, the drawings are only used for understanding and are not drawn to scale. Hence, the drawings are not meant to limit the actual embodiments of the present disclosure. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts for better understanding.
In the description herein and throughout the claims that follow, unless otherwise defined, all terms have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. In the description herein and throughout the claims that follow, the terms “comprise” or “comprising,” “include” or “including,” “have” or “having,” “contain” or “containing” and the like used herein are to be understood to be open-ended, i.e., to mean including but not limited to.
A description is provided with reference to
In some embodiments, the stage 110(n) of the scan driver generates and outputs the scan signal S2N(n) to the N-type transistor TN1. In some embodiments, an enable voltage of the scan signal S2N(n) is at a high logic level, and a disable voltage of the scan signal S2N(n) is at a low logic level. In some embodiments, since the N-type transistor TN1 has the characteristics of low leakage current, the configuration of the N-type transistor TN1 can reduce the leakage current in the pixel circuit 120(n), in order to improve the image quality.
A description is provided with reference to
In some embodiments, a first terminal of the N-type transistor TN1 is electrically coupled to a gate terminal of the driving transistor Td and a second terminal of the storage capacitor Cst, and a second terminal of the N-type transistor TN1 is electrically coupled to a second terminal of the driving transistor Td, and a second terminal of the N-type transistor TN1 is electrically coupled to a second terminal of the driving transistor Td. In some embodiments, a gate terminal of the N-type transistor TN1 is configured to receive a scan signal S2N(n), and the N-type transistor TN1 is turned on according to the scan signal S2N(n). In some embodiments, the N-type transistor TN1 connected between the gate terminal and the second terminal of the driving transistor Td is to compensate a threshold voltage of the driving transistor Td. In some embodiments, the N-type transistor TN1 connected between the gate terminal of the driving transistor Td and the first reference voltage terminal Vn is to reset the voltage at the gate terminal of the driving transistor Td. In some embodiments, since the N-type transistor TN1 has the characteristics of low leakage current, when the N-type transistor TN1 is turned off, it can avoid the decreasing of the voltage maintained by the storage capacitor Cst, as such the quality of display image can be improved.
In some embodiments, a first terminal of the P-type transistor TP1 is electrically coupled to the second terminal of the N-type transistor TN1, and a second terminal of the P-type transistor TP1 is electrically coupled to the first reference voltage terminal Vn. In some embodiments, a gate terminal of the P-type transistor TP1 is configured to receive a scan signal S1(n), and the P-type transistor TP1 is turned on according to the scan signal S1(n). In some embodiments, the P-type transistor TP1 connected between the second terminal of the N-type transistor TN1 and the first reference voltage terminal Vn is configured to reset the voltage at the gate terminal of the driving transistor Td via the N-type transistor TN1.
In some embodiments, a first terminal of the N-type transistor TN2 is configured to receive a data signal DATA, a second terminal of the N-type transistor TN2 is electrically coupled to a first terminal of the storage capacitor Cst. In some embodiments, a gate terminal of the N-type transistor TN2 is configured to receive the scan signal S2N(n). In some embodiments, the data signal DATA is provided by a source driver (not shown). In some embodiments, both of the N-type transistors TN2 and TN1 are controlled by the scan signal S2N(n), as such the number of the scan signals, transmission lines and the area of the circuit for generating additional scan signals can be reduced.
In some embodiments, a first terminal of the P-type transistor TP2 is electrically coupled to the second reference voltage terminal Vp, and a second terminal of the P-type transistor TP2 is electrically coupled to a second terminal of the N-type transistor TN2. A gate terminal of the P-type transistor TP2 is configured to receive an emission control signal EM(n). In some embodiments, a voltage of the second reference voltage terminal Vp is higher than a voltage of the first reference voltage terminal Vn. In some embodiments, the emission control signal EM(n) is provided by a n-th stage of a emission driver (not shown).
In some embodiments, a first terminal of the P-type transistor TP3 is electrically coupled to the second terminal of the driving transistor Td, and a second terminal of the P-type transistor TP3 is electrically coupled to a first terminal of the light emitting element L1. A gate terminal of the P-type transistor TP2 is configured to receive the emission control signal EM(n). In some embodiments, a voltage of the second reference voltage terminal Vp is higher than a voltage of the first reference voltage terminal Vn.
In some embodiments, a first terminal of the driving transistor Td is electrically coupled to the first system voltage terminal OVDD, and a second terminal of the driving transistor Td is electrically coupled to the first terminal of the P-type transistor TP3. A gate terminal of the driving transistor Td is electrically coupled to the second terminal of the storage capacitor Cst. In some embodiments, the driving transistor Td and the light emitting element L1 are connected between a first system voltage terminal OVDD and a second system voltage terminal OVSS, as such the driving transistor Td controls an amplitude of the driving current flowing through the light emitting element L1 according to a voltage at the gate terminal of the driving transistor Td, in order to control the light intensity of the light emitting element L1.
In some embodiments, a first terminal of the light emitting element L1 is electrically coupled to a second terminal of the P-type transistor TP3, and a second terminal of the light emitting element L1 is electrically coupled to the second system voltage terminal OVSS. In some embodiments, the light emitting element L1 emits light according to the driving current controlled/provided by the driving transistor Td.
To make the overall operation of the pixel circuit 120(n) more clear and understandable, the following description is provided with reference to
In the reset period PRES, the scan signals S1(n) and S2N(n) have enable voltages, where the enable voltage of the scan signal S1(n) is at the first logic level (such as, the low logic level), and the enable voltage of the scan signal S2N(n) is at the second logic level (such as, the high logic level). On the other hand, the emission control signal EM(n) has a disable voltage, the disable voltage is at the high logic level.
In the compensation period PCOM, the scan signal S2N(n) has an enable voltage. On the other hand, the scan signal S1(n) and the emission control signal EM(n) have disable voltages, where the disable voltage of the scan signal S1(n) is at the second logic level (such as, the high logic level).
In the emission period PEM, the emission control signal EM(n) has an enable voltage, where the enable voltage of the emission control signal EM(n) is at the first logic level (such as, the low logic level). On the other hand, the scan signals S1(n) and S2N(n) have the disable voltages, where the disable voltage of the scan signal S2N(n) is at the first logic level (such as, the low logic level).
In the reset period PRES, since the scan signals S1(n) and S2N(n) have enable voltages, the P-type transistor TP1 and the N-type transistors TN1 and TN2 are turned on. On the other hand, since the emission control signal EM(n) has a disable voltage, the P-type transistors TP2 and TP3 are turned off.
Specifically, in the reset period PRES, when the data signal DATA is transmitted through the N-type transistor TN2 to the first terminal of the storage capacitor Cst, the voltage of the first reference voltage terminal Vn is transmitted through the P-type transistor TP1 and the N-type transistor TN1 to the gate terminal of the driving transistor Td, in order to turn on the driving transistor Td and perform the reset operation.
In the compensation period PCOM, since the scan signal S2N(n) has the enable voltage, the N-type transistors TN1 and TN2 are turned on. On the hand, since the scan signal S1(n) and the emission control signal EM(n) have the disable voltages, the P-type transistors TP1, TP2 and TP3 are turned off.
Specifically, in the compensation period PCOM, when the data signal DATA is transmitted though the N-type transistor TN2 to the first terminal of the storage capacitor Cst, the voltage of the first system voltage terminal OVDD is transmitted through the driving transistor Td and the N-type transistor TN1 to the gate terminal of the driving transistor Td, until the driving transistor Td is cut-off, as such the voltage at the second terminal of the storage capacitor Cst includes the information of the threshold voltage of the driving transistor Td, in order to perform the operation for compensating the threshold voltage of the driving transistor Td.
In the emission period PEM, since the emission control signal EM(n) has the enable voltage, the P-type transistors TP2 and TP3 are turned on. On the other hand, since the scan signals S1(n) and S2N(n) have the disable voltages, the N-type transistors TN1 and TN2 and the P-type transistor TP1 are turned off.
Specifically, at the beginning of the emission period PEM, the voltage of the second reference voltage terminal Vp is transmitted through the P-type transistor TP2 to the first terminal of the storage capacitor Cst. Meanwhile, the voltage at the first terminal of the storage capacitor Cst is varied from a voltage of the data signal DATA transmitted in the compensation period PCOM to a voltage of the second reference voltage terminal Vp, this voltage variation is transferred though the storage capacitor Cst to the second terminal of the storage capacitor Cst by capacitive coupling, as such the voltage at the second terminal of the storage capacitor Cst includes the information of the voltage of the data signal DATA and the threshold voltage of the driving transistor Td. As a result, in the emission period PEM, the driving current Id flows from the first system voltage terminal OVDD through the driving transistor Td, the P-type transistor TP3 and the light emitting element L1 to the second system voltage terminal OVSS. In some embodiments, the driving transistor Td controls the pulse amplitude of the driving current Id flowing through the light emitting element L1 according to the voltage at the gate terminal of the driving transistor Td (or the voltage at the second terminal of the storage capacitor Cst), in order to control the light intensity of the light emitting element L1.
A description is provided with reference to
In some embodiments, a first terminal and a gate terminal of the transistor T1 is configured to receive a previous scan signal S2N(n−1), and a second terminal of the transistor T1 is electrically coupled to the operating node BT. In some embodiments, the stage 110(n) of the scan driver can be considered as a current stage of the scan driver, and the stage 110(n) of the scan driver receives the previous scan signal S2N(n−1) output by a previous stage of the scan driver. In some embodiments, the enable voltages of the previous scan signal S2N(n−1) and the scan signal S2N(n) are at the second logic level (such as, the high logic level). In some embodiments, a first terminal of the transistor T2 is configured to receive a first clock signal CK45, and a second terminal of the transistor T2 is configured to output the first scan signal S1(n). A gate terminal of the transistor T2 is electrically coupled to the operating node BT. In some embodiments, a first terminal of the transistor T3 is configured to receive a second clock signal CK123, and a second terminal of transistor T3 is configured to output a second scan signal S2N(n). A gate terminal of the transistor T3 is electrically coupled to the operating node BT. In some embodiments, a first terminal of the capacitor C1 is electrically coupled to the operating node BT, and a second terminal of the capacitor C1 is electrically coupled to a second terminal of the transistor T3.
In some embodiments, a first terminal and a gate terminal of the transistor T4 is configured to receive a third clock signal CK231, a second terminal of the transistor T4 is electrically coupled to the voltage stabilizing node P. In some embodiments, a first terminal of the transistor T5 is electrically coupled to the operating node BT, and a second terminal of the transistor T5 is electrically coupled to the system low voltage terminal VGL. A gate terminal of the transistor T5 is electrically coupled to the voltage stabilizing node P. In some embodiments, a first terminal of the transistor T6 is electrically coupled to the second terminal of the transistor T2, and a second terminal of the transistor T6 is electrically coupled to the system high voltage terminal VGH. A gate terminal of the transistor T6 is electrically coupled to the voltage stabilizing node P. In some embodiments, a first terminal of the transistor T7 is electrically coupled to a second terminal of the transistor T3, and a second terminal of the transistor T7 is electrically coupled to the system low voltage terminal VGL. A gate terminal of the transistor T7 is electrically coupled to the voltage stabilizing node P.
In some embodiments, a first terminal of the transistor T8 is electrically coupled to the voltage stabilizing node P, and a second terminal of the transistor T8 is electrically coupled to the system low voltage terminal VGL. A gate terminal of the transistor T8 is electrically coupled to the operating node BT. In some embodiments, a first terminal of the capacitor C2 is electrically coupled to the voltage stabilizing node P, and a second terminal of the capacitor C2 is electrically coupled to the system low voltage terminal VGL.
A description is provided with reference to
As shown in
In the period PNn, the transistor T3 is turned on according to the voltage at the operating node BT, as such the scan signal S2N(n) is maintained at the enable voltage. And, in this period, the transistor T8 is turned on according to the voltage at the operating node BT, in order to pull down the potential at the voltage stabilizing node P to the potential of the system low voltage terminal VGL.
In the period PNn+1, when the transistor T4 is turned on according to the third clock signal CK231, and the third clock signal CK231 is transmitted to the voltage stabilizing node P, the transistor T5 is turned on to pull down the potential at the operating node BT to the potential of the system low voltage terminal VGL, in order to turn off the transistors T2 and T3. The transistor T6 is turned on to transmit the voltage of the system high voltage terminal VGH to the second terminal of the transistor T2, and the transistor T7 is turned on to transmit the voltage of the system low voltage terminal VG to the second terminal of the transistor T3, in order to perform the voltage stabling operation.
A description is provided with reference to
In some embodiments, the display device 100 includes multiple stages of the scan driver, and there is a configuration for applying the clock signals to the pins of the said multiple stages of the scan driver, and the configuration for applying the clock signals is repeated with every 6 stages of the scan driver. Specifically, if the positive integer “n” about the n-th stage 110(n) of the scan driver is divided by 6 and leaves a remainder of 1 (such as, the first stage 110(1) of the scan driver), the first clock signal CK45 applied to the stage 110(n) of the scan driver is implemented by a clock signal CK4. The second clock signal CK123 applied to the stage 110(n) of the scan driver is implemented by a clock signal CK1, and the third clock signal CK231 applied to the stage 110(n) of the scan driver is implemented by a clock signal CK2.
If the positive integer “n” about the n-th stage 110(n) of the scan driver is divided by 6 and leaves a remainder of 2 (such as, the second stage 110(2) of the scan driver), the first clock signal CK45 applied to the stage 110(n) of the scan driver is implemented by a clock signal CK5. The second clock signal CK123 applied to the stage 110(n) of the scan driver is implemented by a clock signal CK2, and the third clock signal CK231 applied to the stage 110(n) of the scan driver is implemented by a clock signal CK3.
If the positive integer “n” about the n-th stage 110(n) of the scan driver is divided by 6 and leaves a remainder of 3 (such as, the third stage 110(3) of the scan driver), the first clock signal CK45 applied to the stage 110(n) of the scan driver is implemented by a clock signal CK4. The second clock signal CK123 applied to the stage 110(n) of the scan driver is implemented by a clock signal CK3, and the third clock signal CK231 applied to the stage 110(n) of the scan driver is implemented by a clock signal CK1.
If the positive integer “n” about the n-th stage 110(n) of the scan driver is divided by 6 and leaves a remainder of 4, the first clock signal CK45 applied to the stage 110(n) of the scan driver is implemented by a clock signal CK5. The second clock signal CK123 applied to the stage 110(n) of the scan driver is implemented by a clock signal CK1, and the third clock signal CK231 applied to the stage 110(n) of the scan driver is implemented by a clock signal CK2.
If the positive integer “n” about the n-th stage 110(n) of the scan driver is divided by 6 and leaves a remainder of 5, the first clock signal CK45 applied to the stage 110(n) of the scan driver is implemented by a clock signal CK4. The second clock signal CK123 applied to the stage 110(n) of the scan driver is implemented by a clock signal CK2, and the third clock signal CK231 applied to the stage 110(n) of the scan driver is implemented by a clock signal CK3.
If the positive integer “n” about the n-th stage 110(n) of the scan driver is divided by 6 and leaves a remainder of 0, the first clock signal CK45 applied to the stage 110(n) of the scan driver is implemented by a clock signal CK5. The second clock signal CK123 applied to the stage 110(n) of the scan driver is implemented by a clock signal CK3, and the third clock signal CK231 applied to the stage 110(n) of the scan driver is implemented by a clock signal CK1.
As shown in
The second stage 110(2) of the scan driver outputs the clock signal CK5 as the scan signal S1(2) according to the scan signal S2N(1) output by the first stage 110(1) of the scan driver, and outputs the clock signal CK2 as the scan signal S2N(2). In some embodiments, the second stage 110(2) of the scan driver outputs the scan signals S1(2) and S2N(2) to the pixel circuit 120(2) arranged in a second pixel line of the pixel array and a third stage 110(3) of the scan driver.
The third stage 110(3) of the scan driver outputs the clock signal CK4 as the scan signal S1(3) according to the scan signal S2N(2) output by the second stage 110(2) of the scan driver, and outputs the clock signal CK3 as the scan signal S2N(3). In some embodiments, the third stage 110(3) of the scan driver outputs the scan signals S1(3) and S2N(3) to the pixel circuit 120(3) arranged in a third pixel line of the pixel array and a fourth stage of the scan driver, and so on.
The sixth stage 110(6) of the scan driver outputs the clock signal CK5 as the scan signal S1(6) according to the scan signal output by the fifth stage of the scan driver, and outputs the clock signal CK3 as the scan signal S2N(6). In some embodiments, the sixth stage 110(6) of the scan driver outputs the scan signals S1(6) and S2N(6) to the pixel circuit 120(6) arranged in a sixth pixel line of the pixel array and a seventh stage of the scan driver.
Summary, the stage 110(n) of the scan driver of the display device 100 in the present disclosure can generate and output the scan signals S1(n) and S2N(n) having the enable voltages at different logic levels to the pixel circuit 120(n), so as to improve the leakage current in the pixel circuit 120(n). Furthermore, the stage 110(n) of the scan driver provided by the present disclosure can generate and output the scan signals S1(n) and S2N(n) having the different enable voltages by the fewer elements and the less circuit area.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims.
Number | Date | Country | Kind |
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112130998 | Aug 2023 | TW | national |