Patent Application
20250218389
This application claims the benefit of Korean Patent Application No. 10-2023-0197303, filed on Dec. 29, 2023, which is hereby incorporated by reference as if fully set forth herein.
The present disclosure relates to a display apparatus, and more particularly to a gate driving circuit and a display apparatus using the same.
Image display apparatuses, which render a variety of information on a screen, are core technologies of the information communication age, and are being developed toward further thinness, further lightness, portability, and higher performance. As such, display apparatuses, which may be manufactured to have a light and thin structure, are being highlighted.
Such a display apparatus is self-luminous and, as such, is not only advantageous in terms of power consumption according to low-voltage driving, but also has fast response time, high luminous efficacy, wide viewing angle, and high contrast ratio. In this regard, such a display apparatus is being highlighted as a next-generation display apparatus and research thereon is being conducted.
As concrete examples of such a display apparatus, there are a liquid crystal display (LCD) apparatus, a quantum dot display (QD) apparatus, a field emission display (FED) apparatus, an organic light emitting display (OLED) apparatus, etc.
The display apparatus includes a panel configured to display an image through pixels disposed in the form of a matrix at intersections of a plurality of gate lines and a plurality of data lines, and a driving circuit configured to drive the panel.
The driving circuit includes a gate driver and a data driver. The gate driver sequentially drives the plurality of gate lines, and the data driver supplies a data voltage to the plurality of data lines.
The gate driver includes a plurality of stages configured to sequentially drive the plurality of gate lines.
Each stage of the gate driving circuit includes a set node, a reset node, a node controller configured to control voltages of the set node and the reset node, and a buffer configured to output a scan signal to a corresponding one of the gate lines in accordance with voltages of the set node and the reset node. Each stage outputs one or two scan signals per frame.
However, among thin film transistors constituting each stage, a thin film transistor configured to be maintained at a low voltage level during an emission period may have a possibility of generation of positive bias temperature stress (PBTS) due to a continuous turn-on state thereof.
The present disclosure is directed to a gate driving circuit and a display apparatus including the same that, among others, substantially obviate one or more problems due to limitations and disadvantages of the related art.
The present disclosure provides a gate driving circuit capable of eliminating positive bias temperature stress (PBTS) through repeated turning on/off of a transistor configured to be continuously turned on in an emission period, thereby achieving an enhancement in reliability thereof, and a display apparatus including the gate driving circuit.
The present disclosure provides a gate driving circuit capable of enhancing a hydrogen (H) capture effect through an increase in the number of oxide transistors constituting the gate driving circuit and an increase in density of titanium (Ti), and a display apparatus including the gate driving circuit.
The present disclosure provides a gate driving circuit capable of reducing a variation in threshold voltage of an oxide transistor through an increase in hydrogen (H) capture effect, and a display apparatus including the gate driving circuit.
Objects of the present disclosure are not limited to the above-described objects, and other objects of the present disclosure not yet described will be more clearly understood by those skilled in the art from the following detailed description.
To achieve these objects and other advantages and in accordance with the purpose of the disclosure, as embodied and broadly described herein, a gate driving circuit includes a Q-node controller configured to control a voltage of a Q-node by first and second clock signals and a start signal or an output signal of an upstream stage, a QB-node controller configured to control a voltage of a QB-node by the second clock signal, a pull-up transistor configured to pull-up drive a logic output terminal in response to the voltage of the Q-node, a pull-down transistor configured to pull-down drive the logic output terminal in response to the voltage of the QB-node, a first inverter transistor configured to supply a gate-low voltage to an output terminal in response to the first clock signal, a second inverter transistor configured to supply a gate-high voltage to the output terminal in response to a voltage of the logic output terminal, and a third inverter transistor configured to supply the gate-low voltage to the output terminal in response to the second clock signal.
Concrete matters of other aspects of the present disclosure are included in the following detailed description of the present disclosure and the accompanying drawings.
The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the disclosure and along with the description serve to explain the principle of the disclosure. In the drawings:
Hereinafter, example embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the description given with reference to the accompanying drawings, the same reference numerals designate the same constituent elements, respectively. In the following description of the present disclosure, a detailed description of known functions and configurations incorporated herein will be omitted when it may obscure the subject matter of the present disclosure. Furthermore, the following terms associated with constituent elements are selected taking into consideration easy preparation of the disclosure, and may differ from the names of the corresponding elements in practice.
The shape, size, ratio, angle, number and the like shown in the drawings to illustrate the embodiments of the present disclosure are only for illustration and are not limited to the contents shown in the drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. In the following description, detailed descriptions of technologies or configurations related to the present disclosure may be omitted so as not to unnecessarily obscure the subject matter of the present disclosure. When terms such as “including,” “having” and “comprising” are used throughout the specification, an additional component may be present, unless “only” is used. A component described in a singular form encompasses components in a plural form unless particularly stated otherwise.
It should be interpreted that the components included in the embodiment of the present disclosure include an error range, although there is no additional particular description thereof.
In describing a variety of embodiments of the present disclosure, when terms for positional relationship such as “on,” “above,” “under” and “next to” are used, at least one intervening element may be present between two elements unless “right” or “direct” is used.
In describing a variety of embodiments of the present disclosure, when a temporal relationship is described, for example, when terms for temporal relationship of events such as “after,” “subsequently,” “next,” and “before” are used, there may also be the case in which the events are not continuous, unless “immediately” or “directly” is used.
In the meantime, although terms including an ordinal number, such as first or second, may be used to describe a variety of constituent elements, the constituent elements are not limited to the terms, and the terms are used only for the purpose of discriminating one constituent element from other constituent elements.
The respective features of various embodiments according to the present disclosure can be partially or entirely joined or combined and technically variably related or operated, and the embodiments can be implemented independently or in combination.
Hereinafter, a gate driving circuit according to an embodiment of the present disclosure and a display apparatus including the same will be described with reference to the accompanying drawings.
As shown in
The display panel 100 includes an active area (AA) in which the pixels P are disposed, and a non-active area (NA) disposed to surround the active area (AA). In the non-active area (NA), the gate driving circuit 300 and the data driving circuit 400 are disposed.
A plurality of gate lines GL and a plurality of data lines DL intersect each other at the display panel 100, and each of the plurality of pixels P is connected to corresponding ones of the gate lines GL and the data lines DL. In detail, each pixel P receives a gate signal from the gate driving circuit 300 through the corresponding gate line GL, receives a data signal from the data driving circuit 400 through the corresponding data line DL, and receives a high-level drive voltage EVDD and a low-level drive voltage EVSS from the power supply 500.
Each gate line GL supplies a scan signal SC and an emission control signal EM to a plurality of pixels P, and each data line DL supplies a data voltage Vdata to a plurality of pixels P. In accordance with various embodiments, each gate line GL may include a plurality of scan lines SCL for supply of the scan signal SC, and a plurality of emission control signal lines EML for supply of the emission control signal EM.
As shown in
The light emitting element OLED may operate to emit light in accordance with a drive current formed by the driving transistor DT.
The switching transistor ST may perform a switching operation to store a data signal supplied through a data line DL in the storage capacitor Cst as a data voltage, corresponding to a scan signal supplied through a gate line GL.
The driving transistor DT may operate to enable a constant drive current to flow between a power line for the high-level drive voltage EVDD and a power line for the low-level drive voltage EVSS, corresponding to the data voltage stored in the storage capacitor Cst.
The compensation circuit CC is a circuit for compensating a threshold voltage, etc., of the driving transistor DT. The compensation circuit CC may include one or more thin film transistors and a capacitor. The configuration of the compensation circuit CC may be very diverse in accordance with compensation methods.
Although the pixel P shown in
The display panel 100 may be implemented as a non-transmissive display panel or a transmissive display panel. The transmissive display panel may be applied to a transparent display apparatus in which an image is displayed on a screen and through which an actual background is visible. The display panel 100 may be implemented as a flexible display panel. The flexible display panel may be implemented as an OLED panel using a plastic substrate.
Each pixel P may be divided into a red pixel, a green pixel, and a blue pixel, for color rendering. Each pixel P may further include a white pixel. Each pixel P may include a pixel circuit.
Touch sensors may be disposed on the display panel 100. Touch input may be sensed using separate touch sensors or may be sensed through pixels P. The touch sensors may be disposed on a screen of the display panel 100 in an on-cell type or an add-on type or may be implemented as in-cell type touch sensors built in the display panel 100.
The controller 200 processes image data RGB input thereto from an outside thereof, to match the size and resolution of the display panel 100, and then supplies the processed image data RGB to the data driving circuit 400. The controller 200 generates a gate control signal GCS and a data control signal DCS using synchronization signals input from the outside thereof, for example, a dot clock signal CLK, a date enable signal DE, a horizontal synchronization signal Hsync, and a vertical synchronization signal Vsync.
The controller 200 supplies the gate control signal GCS to the gate driving circuit 300, thereby controlling an operation timing of the gate driving circuit 300. The controller 200 supplies the data control signal DCS to the data driving circuit 400, thereby controlling an operation timing of the data driving circuit 400. The controller 200 synchronizes operation timings of the gate driving circuit 300 and the data driving circuit 400 using the gate control signal GCS and the data control signal DCS.
The controller 200 may be configured to be coupled with various processors, for example, a microprocessor, a mobile processor, an application processor, etc., in accordance with a device mounted therein.
A host system, which is applied to the controller 200, may be one of a television (TV) system, a set-top box, a navigation system, a personal computer (PC), a home theater system, a mobile appliance, a wearable appliance, and a vehicle system.
The controller 200 may multiply an input frame frequency by i times, thereby controlling the operation timings of the display panel drivers at a frame frequency corresponding to an “input frame frequency x i” Hz (i being a positive integer greater than 0). The input frame frequency is 60 Hz in a national television standards committee (NTSC) system, and is 50 Hz in a phase-alternating line (PAL) system.
The controller 200 may drive each pixel P at various refresh rates. The controller 200 may drive each pixel P in a variable refresh rate (VRR) mode, in other words, to be switched between a first refresh rate and a second refresh rate. For example, the controller 200 may drive each pixel P at various refresh rates by simply varying a rate of a clock signal, generating a synchronization signal, for generation of a horizontal blank or a vertical blank, or driving the gate driving circuit 300 in a mask manner.
The voltage level of the gate control signal GCS output from the controller 200 may be converted into a gate-low voltage VGL/VEL and a gate-high voltage VGH/VEH through a level shifter (not shown), and the gate-low voltage VGL/VEL and the gate-high voltage VGH/VEH may then be supplied to the gate driving circuit 300. The level shifter converts a low-level voltage of the gate control signal GCS into a gate-low voltage VGL, and converts a high-level voltage of the gate control signal GCS into a gate-high voltage VGH. The gate control signal GCS includes a start pulse and a shift clock.
The gate driving circuit 300 supplies a gate signal to each gate line GL in accordance with a gate control signal supplied from the controller 200. The gate driving circuit 300 may be disposed at one side or both sides of the display panel 100 in a gate-in-panel manner.
The gate driving circuit 300 sequentially outputs a gate signal to a plurality of gate lines GL under control of the controller 200. The gate driving circuit 300 may shift the gate signal using a shift register and, as such, may sequentially supply shifted gate signals to the gate lines GL, respectively.
The gate signal may include a scan signal SC and an emission control signal EM in an organic light emitting display apparatus. The scan signal SC includes a scan pulse that swings between a gate-low voltage VGL and a gate-high voltage VGH. The emission control signal EM may include an emission control signal pulse that swings between a gate-low voltage VEL and a gate-high voltage VEH. The scan pulse selects pixels P of a line on which a data voltage Vdata will be written. The emission control signal EM defines an emission time of the pixels P.
The gate driving circuit 300 may include at least one scan driver 310 and an emission control signal driver 320.
The emission control signal driver 320 outputs an emission control signal pulse in response to a start pulse and a shift clock from the controller 200, and sequentially shifts the emission control signal pulse in accordance with the shift clock.
The at least one scan driver 310 outputs a scan pulse in response to the start pulse and the shift clock from the controller 200, and shifts the scan pulse in accordance with a timing of the shift clock.
The data driving circuit 400 converts image data RGB into a data voltage Vdata in accordance with a data control signal DCS supplied from the controller 200, and supplies the data voltage Vdata to the pixels P through the data lines DL.
Although the data driving circuit 400 is shown in
The power supply 500 generates DC power required for driving of the pixel array and the display panel drivers of the display panel 100, using a DC-DC converter. The DC-DC converter may include a charge pump, a regulator, a buck converter, a boost converter, etc.
The power supply 500 may receive a DC input voltage from a host system (not shown), thereby generating DC voltages such as a gate-low voltage VGL/VEL, a gate-high voltage VGH/VEH, a high-level drive voltage EVDD, a low-level drive voltage EVSS, etc.
The gate-low voltage VGL/VEL and the gate-high voltage VGH/VEH are supplied to the level shifter (not shown) and the gate driving circuit 300. The high-level drive voltage EVDD and the low-level drive voltage EVSS are supplied to the pixels P in common.
Referring to
The pull-up transistor T1 may pull-up drive a logic output terminal OUT_logic(n) in response to a signal of a Q-node Q. The pull-down transistor T2 may pull-down drive the logic output terminal OUT_logic(n) in response to a signal of a QB-node QB.
The transfer transistor TA transfers a charge of a Q2-node Q2 to the Q-node Q in response to a gate-low voltage VGL.
The first transistor T3 supplies a start signal GVST or an output signal OUT_AA(n-1) of an upstream stage to the Q2-node Q2 in response to a second clock signal CLK2.
The second transistor T4 supplies the second clock signal CLK2 to the QB-node QB in response to a voltage of the Q2-node Q2.
The third transistor T5 supplies the gate-low voltage VGL to the QB-node QB in response to the second clock signal CLK2.
The fourth transistor T6 supplies a gate-high voltage VGH to the fifth transistor T7 in response to a voltage of the QB-node QB.
The fifth transistor T7 supplies, to the Q2-node Q2, the gate-high voltage VGH supplied through the fourth transistor T6, in response to a first clock signal CLK1.
The first inverter transistor T8 supplies the gate-low voltage VGL to an output terminal OUT_AA(n), to which a gate line is connected, in response to a voltage of the logic output terminal OUT_logic(n).
The second inverter transistor T9 supplies the gate-high voltage VGH to the output terminal OUT_AA(n), to which the gate line is connected, in response to the voltage of the logic output terminal OUT_logic(n).
The first capacitor CQ is coupled between the Q-node Q and the logic output terminal OUT_logic(n). The second capacitor CQB is coupled between the QB-node QB and a gate-high voltage line configured to supply the gate-high voltage VGH.
Here, the pull-up transistor T1, the pull-down transistor T2, the transfer transistor TA, the first transistor T3, the second transistor T4, the third transistor T5, the fourth transistor T6, the fifth transistor T7, the first inverter transistor T8, and the second inverter transistor T9 may be constituted by transistors of different types.
For example, one of the pull-up transistor T1, the pull-down transistor T2, the transfer transistor TA, the first transistor T3, the second transistor T4, the third transistor T5, the fourth transistor T6, the fifth transistor T7, the first inverter transistor T8, and the second inverter transistor T9 may be an oxide transistor including an oxide semiconductor material as an active layer thereof. The oxide semiconductor material exhibits low off-current and, as such, is suitable for a switching transistor maintaining a short turn-on time and a long turn-off time.
In another example, another one of the pull-up transistor T1, the pull-down transistor T2, the transfer transistor TA, the first transistor T3, the second transistor T4, the third transistor T5, the fourth transistor T6, the fifth transistor T7, the first inverter transistor T8, and the second inverter transistor T9 may be a transistor including a low-temperature polysilicon (LTPS) material as an active layer thereof. Such a polysilicon material exhibits high mobility, thereby exhibiting low power consumption and excellent reliability, and, as such, is suitable for a driving transistor DT.
Meanwhile, the pull-up transistor T1, the pull-down transistor T2, the transfer transistor TA, the first transistor T3, the second transistor T4, the third transistor T5, the fourth transistor T6, the fifth transistor T7, the first inverter transistor T8, and the second inverter transistor T9 may be N-type transistors or P-type transistors.
In an N-type transistor, carriers are electrons and, as such, electrons may flow from a source electrode to a drain electrode, and current may flow from the drain electrode to the source electrode. In a P-type transistor, carriers are holes and, as such, holes may flow from a source electrode to a drain electrode, and current may flow from the source electrode to the drain electrode.
For example, one of the pull-up transistor T1, the pull-down transistor T2, the transfer transistor TA, the first transistor T3, the second transistor T4, the third transistor T5, the fourth transistor T6, the fifth transistor T7, the first inverter transistor T8, and the second inverter transistor T9 may be an N-type transistor, and another one of the remaining transistors may be a P-type transistor.
In addition, the first inverter transistor T8 may be an oxide transistor.
In
Hereinafter, operation of the scan driver of the display apparatus according to the first embodiment of the present disclosure will be described. In the drawings (except for
As shown in
In this state, the Q2-node Q2 and the Q-node Q maintain a low-level voltage which is the low level of the start signal GVST or the output signal OUT_AA(n-1) of the upstream stage, and the QB-node QB also maintains the gate-low voltage VGL.
Accordingly, the pull-up transistor T1 and the pull-down transistor T2 are turned on and, as such, the logic output terminal OUT_logic(n) outputs the gate-high voltage VGH.
In addition, the first inverter transistor T8 is turned on and the second inverter transistor T9 is turned off by the gate-high voltage VGH of the logic output terminal OUT_logic(n). Accordingly, the output terminal OUT_AA(n) outputs the gate-low voltage VGL.
As shown in
In this state, the Q2-node Q2 and the Q-node Q maintain a low-level voltage of the start signal GVST or the output signal OUT_AA(n-1) of the upstream stage, and the QB-node QB maintains a high-level voltage of the second clock signal CLK2.
Accordingly, the pull-up transistor T1 is turned on, and the pull-down transistor T2 and the fourth transistor T6 are turned off, and, as such, the logic output terminal OUT_logic(n) outputs a low-level voltage of the first clock signal CLK1.
In addition, the first inverter transistor T8 is turned off and the second inverter transistor T9 is turned on by the low-level voltage of the first clock signal CLK1 of the logic output terminal OUT_logic(n). Accordingly, the output terminal OUT_AA(n) outputs the gate-high voltage VGH.
As shown in
Accordingly, the pull-up transistor T1 is turned off, and the pull-down transistor T2 and the fourth transistor T6 are turned on, and, as such, the logic output terminal OUT_logic(n) outputs the gate-high voltage VGH.
In addition, the first inverter transistor T8 is turned on and the second inverter transistor T9 is turned off by the gate-high voltage VGH of the logic output terminal OUT_logic(n). Accordingly, the output terminal OUT_AA(n) outputs the gate-low voltage VGL.
As shown in
Accordingly, the pull-up transistor T1 is turned off, and the pull-down transistor T2 and the fourth transistor T6 are turned on, and, as such, the logic output terminal OUT_logic(n) outputs the gate-high voltage VGH.
In addition, the first inverter transistor T8 is turned on and the second inverter transistor T9 is turned off by the gate-high voltage VGH of the logic output terminal OUT_logic(n). Accordingly, the output terminal OUT_AA(n) maintains the gate-low voltage VGL.
As described above, the scan driver of the display apparatus according to the first embodiment of the present disclosure outputs a scan signal to the output terminal OUT_AA(n) through operation of the first inverter transistor T8 and the second inverter transistor T9 (t2), and the first inverter transistor T8 maintains a turn-on state until a next frame starts (t3-t4-t1), after outputting of the scan signal.
Accordingly, the first inverter transistor T8 may undergo positive bias temperature stress (PBTS).
As can be seen from
When the first inverter transistor T8 undergoes PBTS due to a reason as described above, a turn-on timing of the first inverter transistor T8 may be delayed, and an output slew rate of the resultant scan signal may be degraded. As a result, the resultant scan signal may be distorted.
The embodiments herein help to prevent the first inverter transistor T8 from undergoing PBTS.
Referring to
The pull-up transistor T1 may pull-up drive a logic output terminal OUT_logic(n) in response to a signal of a Q-node Q. The pull-down transistor T2 may pull-down drive the logic output terminal OUT_logic(n) in response to a signal of a QB-node QB.
The transfer transistor TA transfers a charge of a Q2-node Q2 to the Q-node Q in response to a gate-low voltage VGL.
The first transistor T3 supplies a start signal GVST or an output signal OUT_AA(n-1) of an upstream stage to the Q2-node Q2 in response to a second clock signal CLK2.
The second transistor T4 supplies the second clock signal CLK2 to the QB-node QB in response to a voltage of the Q2-node Q2.
The third transistor T5 supplies the gate-low voltage VGL to the QB-node QB in response to the second clock signal CLK2.
The fourth transistor T6 supplies a gate-high voltage VGH to the fifth transistor T7 in response to a voltage of the QB-node QB.
The fifth transistor T7 supplies, to the Q2-node Q2, the gate-high voltage VGH supplied through the fourth transistor T6, in response to a first clock signal CLK1.
The first inverter transistor T8 supplies the gate-low voltage VGL to an output terminal OUT_AA(n), to which a gate line is connected, in response to the first clock signal CLK1.
The second inverter transistor T9 supplies the gate-high voltage VGH to the output terminal OUT_AA(n), to which the gate line is connected, in response to a voltage of the logic output terminal OUT_logic(n).
The third inverter transistor T10 supplies the gate-low voltage VGL to the output terminal OUT_AA(n), to which the gate line is connected, in response to the second clock signal CLK2.
The first capacitor CQ1 is coupled between the Q-node Q and the logic output terminal OUT_logic(n). The second capacitor CQB is coupled between the QB-node QB and a gate-high voltage line configured to supply the gate-high voltage VGH. The third capacitor CQ2 is coupled between a gate of the first inverter transistor T8 and the output terminal OUT_AA(n).
Here, the pull-up transistor T1, the pull-down transistor T2, the transfer transistor TA, the first transistor T3, the second transistor T4, the third transistor T5, the fourth transistor T6, the fifth transistor T7, the first inverter transistor T8, the second inverter transistor T9, and the third inverter transistor T10 may be constituted by transistors of different types.
For example, one of the pull-up transistor T1, the pull-down transistor T2, the transfer transistor TA, the first transistor T3, the second transistor T4, the third transistor T5, the fourth transistor T6, the fifth transistor T7, the first inverter transistor T8, the second inverter transistor T9, and the third inverter transistor T10 may be an oxide transistor including an oxide semiconductor material as an active layer thereof. The oxide semiconductor material exhibits low off-current and, as such, is suitable for a switching transistor maintaining a short turn-on time and a long turn-off time.
In another example, another one of the pull-up transistor T1, the pull-down transistor T2, the transfer transistor TA, the first transistor T3, the second transistor T4, the third transistor T5, the fourth transistor T6, the fifth transistor T7, the first inverter transistor T8, the second inverter transistor T9, and the third inverter transistor T10 may be a transistor including a low-temperature polysilicon (LTPS) material as an active layer thereof. Such a polysilicon material exhibits high mobility, thereby exhibiting low power consumption and excellent reliability, and, as such, is suitable for a driving transistor DT.
Meanwhile, the pull-up transistor T1, the pull-down transistor T2, the transfer transistor TA, the first transistor T3, the second transistor T4, the third transistor T5, the fourth transistor T6, the fifth transistor T7, the first inverter transistor T8, the second inverter transistor T9, and the third inverter transistor T10 may be N-type transistors or P-type transistors.
In an N-type transistor, carriers are electrons and, as such, electrons may flow from a source electrode to a drain electrode, and current may flow from the drain electrode to the source electrode. In a P-type transistor, carriers are holes and, as such, holes may flow from a source electrode to a drain electrode, and current may flow from the source electrode to the drain electrode.
In addition, the first inverter transistor T8 may be an oxide transistor.
In
and the fifth transistor T7 may be referred to as a Q-node controller 1 configured to control a voltage of the Q-node Q, and the second transistor T4 and the third transistor T5 may be referred to as a QB node controller 2 configured to control a voltage of the QB-node QB.
Hereinafter, operation of the scan driver of the display apparatus according to the second embodiment of the present disclosure will be described.
As shown in
In this state, the Q2-node Q2 and the Q-node Q maintain a low-level voltage which is the low level of the start signal GVST or the output signal OUT_AA(n-1) of the upstream stage, and the QB-node QB also maintains the gate-low voltage VGL.
Accordingly, the pull-up transistor T1 and the pull-down transistor T2 are turned on and, as such, the logic output terminal OUT_logic(n) outputs the gate-high voltage VGH.
In addition, the second inverter transistor T9 is turned off by the gate-high voltage VGH of the logic output terminal OUT_logic(n). Accordingly, the output terminal OUT_AA(n) outputs the gate-low voltage VGL by the first inverter transistor T8 and the third inverter transistor T10 which are in a turn-on state.
As shown in
In this state, the Q2-node Q2 and the Q-node Q maintain a low-level voltage of the start signal GVST or the output signal OUT_AA(n-1) of the upstream stage, and a voltage of the QB-node QB is changed into a high-level voltage of the second clock signal CLK2.
Accordingly, the pull-up transistor T1 is turned on, and the pull-down transistor T2 and the fourth transistor T6 are turned off, and, as such, the logic output terminal OUT_logic(n) outputs a low-level voltage of the first clock signal CLK1.
In addition, the second inverter transistor T9 is turned on by the low-level voltage of the first clock signal CLK1 of the logic output terminal OUT_logic(n). Accordingly, the output terminal OUT_AA(n) outputs the gate-high voltage VGH.
As shown in
Accordingly, the pull-up transistor T1 is turned on, and the pull-down transistor T2 and the fourth transistor T6 are turned off, and, as such, the logic output terminal OUT_logic(n) outputs a high-level voltage of the first clock signal CLK1.
In addition, the second inverter transistor T9 is turned off by the high-level voltage of the first clock signal CLK1 of the logic output terminal OUT_logic(n), and the first inverter transistor T8 is turned on by the first clock signal CLK1. Accordingly, the output terminal OUT_AA(n) outputs the gate-low voltage VGL.
As shown in
Accordingly, the pull-up transistor T1 is turned off, and the pull-down transistor T2 and the fourth transistor T6 are turned on, and, as such, the logic output terminal OUT_logic(n) outputs the gate-high voltage VGH.
In addition, the second inverter transistor T9 is turned off by the gate-high voltage VGH of the logic output terminal OUT_logic(n), the first inverter transistor T8 is turned on by the first clock signal CLK1, and the third inverter transistor T10 is turned on by the second clock signal CLK2. Accordingly, the output terminal OUT_AA(n) maintains the gate-low voltage VGL.
As shown in
Accordingly, the pull-up transistor T1 is turned off, and the pull-down transistor T2 and the fourth transistor T6 are turned on, and, as such, the logic output terminal OUT_logic(n) outputs the gate-high voltage VGH.
In addition, the second inverter transistor T9 is turned off by the gate-high voltage VGH of the logic output terminal OUT_logic(n), and the first inverter transistor T8 and the third inverter transistor T10 are turned off by the first clock signal CLK1 and the second clock signal CLK2, respectively. Accordingly, the output terminal OUT_AA(n) maintains the gate-low voltage VGL.
As apparent from the above description, the scan driver of the display apparatus according to the second embodiment of the present disclosure outputs a scan signal at the output terminal OUT_AA(n), as described above with reference to
In the gate driving circuit according to the second embodiment of the present disclosure as described above, the first inverter transistor T8 is maintained in a turn-off state in the fifth period t5 described with reference to
Since the gate driving circuit according to the second embodiment of the present disclosure is configured such that the first inverter transistor does not undergo PBTS, reliability of the gate driving circuit may be enhanced.
Since the first inverter transistor does not undergo PBTS, it may be possible to reduce a failure rate of the display apparatus. Accordingly, it may be possible to reduce production energy for production of the display apparatus and to reduce generation of greenhouse gases caused by a manufacturing process for the display apparatus. Thus, environment/social/governance (ESG) goals may be achieved.
Meanwhile,
Referring to
The pull-up transistor T1 may pull-up drive a logic output terminal OUT_logic(n) in response to a signal of a Q-node Q. The pull-down transistor T2 may pull-down drive the logic output terminal OUT_logic(n) in response to a signal of a QB-node QB.
The transfer transistor TA transfers a charge of a Q2-node Q2 to the Q-node Q in response to a gate-low voltage VGL.
The first transistor T3 supplies a start signal GVST or an output signal OUT_AA(n-1) of an upstream stage to the Q2-node Q2 in response to a second clock signal CLK2.
The second transistor T4 supplies the second clock signal CLK2 to the QB-node QB in response to a voltage of the Q2-node Q2.
The third transistor T5 supplies the gate-low voltage VGL to the QB-node QB in response to the second clock signal CLK2.
The fourth transistor T6 supplies a gate-high voltage VGH to the fifth transistor T7 in response to a voltage of the QB-node QB.
The fifth transistor T7 supplies, to the Q2-node Q2, the gate-high voltage VGH supplied through the fourth transistor T6, in response to a first clock signal CLK1.
The first inverter transistor T8 supplies the gate-low voltage VGL to an output terminal OUT_AA(n), to which a gate line is connected, in response to the first clock signal CLK1.
The second inverter transistor T9 supplies the gate-high voltage VGH to the output terminal OUT_AA(n), to which the gate line is connected, in response to a voltage of the logic output terminal OUT_logic(n).
The third inverter transistor T10 supplies the gate-low voltage VGL to the fourth inverter transistor T11 in response to the second clock signal CLK2.
The fourth inverter transistor T11 supplies, to the output terminal OUT_AA(n), to which the gate line is connected, the gate-low voltage VGL supplied through the third inverter transistor T10, in response to the voltage of the logic output terminal OUT_logic(n).
The first capacitor CQ is coupled between the Q-node Q and the logic output terminal OUT_logic(n). The second capacitor CQB is coupled between the QB-node QB and a gate-high voltage line configured to supply the gate-high voltage VGH.
Here, the pull-up transistor T1, the pull-down transistor T2, the transfer transistor TA, the first transistor T3, the second transistor T4, the third transistor T5, the fourth transistor T6, the fifth transistor T7, the first inverter transistor T8, the second inverter transistor T9, the third inverter transistor T10, and the fourth inverter transistor T11 may be constituted by transistors of different types.
For example, one of the pull-up transistor T1, the pull-down transistor T2, the transfer transistor TA, the first transistor T3, the second transistor T4, the third transistor T5, the fourth transistor T6, the fifth transistor T7, the first inverter transistor T8, the second inverter transistor T9, the third inverter transistor T10, and the fourth inverter transistor T11 may be an oxide transistor including an oxide semiconductor material as an active layer thereof. The oxide semiconductor material exhibits low off-current and, as such, is suitable for a switching transistor maintaining a short turn-on time and a long turn-off time.
In another example, another one of the pull-up transistor T1, the pull-down transistor T2, the transfer transistor TA, the first transistor T3, the second transistor T4, the third transistor T5, the fourth transistor T6, the fifth transistor T7, the first inverter transistor T8, the second inverter transistor T9, the third inverter transistor T10, and the fourth inverter transistor T11 may be a transistor including a low-temperature polysilicon (LTPS) material as an active layer thereof. Such a polysilicon material exhibits high mobility, thereby exhibiting low power consumption and excellent reliability, and, as such, is suitable for a driving transistor DT.
Meanwhile, the pull-up transistor T1, the pull-down transistor T2, the transfer transistor TA, the first transistor T3, the second transistor T4, the third transistor T5, the fourth transistor T6, the fifth transistor T7, the first inverter transistor T8, the second inverter transistor T9, the third inverter transistor T10, and the fourth inverter transistor T11 may be N-type transistors or P-type transistors.
In an N-type transistor, carriers are electrons and, as such, electrons may flow from a source electrode to a drain electrode, and current may flow from the drain electrode to the source electrode. In a P-type transistor, carriers are holes and, as such, holes may flow from a source electrode to a drain electrode, and current may flow from the source electrode to the drain electrode.
In addition, the first inverter transistor T8, the third inverter transistor T10, and the fourth inverter transistor T11 may be oxide transistors.
When the first inverter transistor T8, the third inverter transistor T10, and the fourth inverter transistor T11 are oxide transistors, a gate electrode, a source electrode, and a drain electrode of each of the transistors T8, T10, and T11 may include titanium (Ti).
In
Hereinafter, operation of the scan driver of the display apparatus according to the third embodiment of the present disclosure will be described.
As shown in
In this state, the Q2-node Q2 and the Q-node Q maintain a low-level voltage which is the low level of the start signal GVST or the output signal OUT_AA(n-1) of the upstream stage, and the QB-node QB also maintains the gate-low voltage VGL.
Accordingly, the pull-up transistor T1 and the pull-down transistor T2 are turned on and, as such, the logic output terminal OUT_logic(n) outputs the gate-high voltage VGH.
In addition, the second inverter transistor T9 is turned off by the gate-high voltage VGH of the logic output terminal OUT_logic(n). Accordingly, the output terminal OUT_AA(n) outputs the gate-low voltage VGL by the first inverter transistor T8 which is in a turn-on state.
As shown in
In this state, the Q2-node Q2 and the Q-node Q maintain a low-level voltage of the start signal GVST or the output signal OUT_AA(n-1) of the upstream stage, and a voltage of the QB-node QB is changed into a high-level voltage of the second clock signal CLK2.
Accordingly, the pull-up transistor T1 is turned on, and the pull-down transistor T2 and the fourth transistor T6 are turned off, and, as such, the logic output terminal OUT_logic(n) outputs a low-level voltage of the first clock signal CLK1.
In addition, the second inverter transistor T9 is turned on by the low-level voltage of the first clock signal CLK1 of the logic output terminal OUT_logic(n). Accordingly, the output terminal OUT_AA(n) outputs the gate-high voltage VGH.
As shown in
Accordingly, the pull-up transistor T1 is turned on, and the pull-down transistor T2 and the fourth transistor T6 are turned off, and, as such, the logic output terminal OUT_logic(n) outputs a high-level voltage of the first clock signal CLK1.
In addition, the second inverter transistor T9 is turned off by the high-level voltage of the first clock signal CLK1 of the logic output terminal OUT_logic(n). Accordingly, the output terminal OUT_AA(n) outputs the gate-low voltage VGL through the first, third, and fourth inverter transistors T8, T10, and T11 which are in a turn-on state.
As shown in
Accordingly, the pull-up transistor T1 is turned off, and the pull-down transistor T2 and the fourth transistor T6 are turned on, and, as such, the logic output terminal OUT_logic(n) outputs the gate-high voltage VGH.
In addition, the second inverter transistor T9 is turned off by the gate-high voltage VGH of the logic output terminal OUT_logic(n), and the first inverter transistor T8 is turned on by the first clock signal CLK1. Accordingly, the output terminal OUT_AA(n) maintains the gate-low voltage VGL.
As shown in
Accordingly, the pull-up transistor T1 is turned off, and the pull-down transistor T2 and the fourth transistor T6 are turned on, and, as such, the logic output terminal OUT_logic(n) outputs the gate-high voltage VGH.
In addition, the second inverter transistor T9 is turned off by the gate-high voltage VGH of the logic output terminal OUT_logic(n), and the third inverter transistor T10 and the fourth inverter transistor T11 are turned on. Accordingly, the output terminal OUT_AA(n) maintains the gate-low voltage VGL.
As apparent from the above description, the scan driver of the display apparatus according to the third embodiment of the present disclosure outputs a scan signal at the output terminal OUT_AA(n), as described above with reference to
In the gate driving circuit according to the third embodiment of the present disclosure as described above, the first inverter transistor T8 is maintained in a turn-off state in the fifth period t5 described with reference to
In the gate driving circuit according to the third embodiment of the present disclosure, the first inverter transistor T8, the third inverter transistor T10, and the fourth inverter transistor T11 may be formed by oxide transistors, respectively, and a gate electrode, a source electrode, and a drain electrode of each of the transistors T8, T10, and T11 may include titanium (Ti). Accordingly, the number of oxide transistors constituting the gate driving circuit may be increased and, as such, the density of titanium (Ti) may be increased. Accordingly, an increase in hydrogen (H) capture effect may be achieved.
The gate driving circuit according to the third embodiment of the present disclosure may stably output a scan signal without a node floated during driving of the gate driving circuit.
In the gate driving circuit according to the third embodiment of the present disclosure, the first inverter transistor does not undergo positive bias temperature stress (PBTS). Accordingly, reliability of the gate driving circuit may be enhanced.
Since the first inverter transistor does not undergo PBTS, it may be possible to reduce a failure rate of the display apparatus. Accordingly, it may be possible to reduce production energy for production of the display apparatus and to reduce generation of greenhouse gases caused by a manufacturing process for the display apparatus. Thus, environment/social/governance (ESG) goals may be achieved.
Gate driving circuits according to various embodiments of the present disclosure may be described as follows.
A gate driving circuit according to an embodiment of the present disclosure may include a Q-node controller configured to control a voltage of a Q-node by first and second clock signals and a start signal or an output signal of an upstream stage, a QB-node controller configured to control a voltage of a QB-node by the second clock signal, a pull-up transistor configured to pull-up drive a logic output terminal in response to the voltage of the Q-node, a pull-down transistor configured to pull-down drive the logic output terminal in response to the voltage of the QB-node, a first inverter transistor configured to supply a gate-low voltage to an output terminal in response to the first clock signal, a second inverter transistor configured to supply a gate-high voltage to the output terminal in response to a voltage of the logic output terminal, and a third inverter transistor configured to supply the gate-low voltage to the output terminal in response to the second clock signal.
A gate driving circuit according to another embodiment of the present disclosure may include a Q-node controller configured to control a voltage of a Q-node by first and second clock signals and a start signal or an output signal of an upstream stage, a QB-node controller configured to control a voltage of a QB-node by the second clock signal, a pull-up transistor configured to pull-up drive a logic output terminal in response to the voltage of the Q-node, a pull-down transistor configured to pull-down drive the logic output terminal in response to the voltage of the QB-node, a first inverter transistor configured to supply a gate-low voltage to an output terminal in response to the first clock signal, a second inverter transistor configured to supply a gate-high voltage to the output terminal in response to a voltage of the logic output terminal, a third inverter transistor configured to output the gate-low voltage in response to the second clock signal, and a fourth inverter transistor configured to supply, to the output terminal, the gate-low voltage output through the third inverter transistor, in response to the voltage of the logic output terminal.
The Q-node controller may include a first transistor configured to supply the start signal or the output signal of the upstream stage to a Q2-node in response to the second clock signal, a transfer transistor configured to transfer a charge of the Q2-node to the Q-node in response to the gate-low voltage, a fourth transistor configured to supply the gate-high voltage in response to the voltage of the QB-node, and a fifth transistor configured to supply, to the Q2-node, the gate-high voltage supplied through the fourth transistor, in response to the first clock signal.
The QB-node controller may include a second transistor configured to supply the second clock signal to the QB-node in response to a voltage of the Q2-node, and a third transistor configured to supply the gate-low voltage to the QB-node in response to the second clock signal.
The gate driving circuit according to each of the embodiments of the present disclosure may further include a first capacitor coupled between the Q-node and the logic output terminal, and a second capacitor coupled between the QB-node and a gate-high voltage line configured to supply the gate-high voltage.
The gate driving circuit according to each of the embodiments of the present disclosure may further include a third capacitor coupled between a gate of the first inverter transistor and the output terminal.
As apparent from the above description, a gate driving circuit according to the present disclosure and a display apparatus including the same has the following effects.
In a gate driving circuit according to an embodiment of the present disclosure, a first inverter transistor T8, a third inverter transistor T10, and a fourth inverter transistor T11 may be formed by oxide transistors, respectively, and a gate electrode, a source electrode, and a drain electrode of each of the transistors T8, T10, and T11 may include titanium (Ti). Accordingly, the number of oxide transistors constituting the gate driving circuit may be increased and, as such, the density of titanium (Ti) may be increased. Accordingly, an increase in hydrogen (H) capture effect may be achieved.
The gate driving circuit according to the embodiment of the present disclosure may stably output a scan signal without a node floated during driving of the gate driving circuit.
In the gate driving circuit according to the embodiment of the present disclosure, a hydrogen (H) capture effect may increase. Accordingly, it may be possible to reduce a variation in threshold voltage of an oxide transistor.
In the gate driving circuit according to the embodiment of the present disclosure, the first inverter transistor is maintained in a turn-off state in a fifth period t5 until a next frame starts, after outputting a scan signal. Accordingly, the first inverter transistor may not undergo positive bias temperature stress (PBTS).
Since the gate driving circuit according to the embodiment of the present disclosure is configured such that the first inverter transistor does not undergo PBTS, reliability of the gate driving circuit may be enhanced.
Since the first inverter transistor does not undergo PBTS, it may be possible to reduce a failure rate of the display apparatus. Accordingly, it may be possible to reduce production energy for production of the display apparatus and to reduce generation of greenhouse gases caused by a manufacturing process for the display apparatus. Thus, environment/social/governance (ESG) goals may be achieved.
Although the example embodiments of the present disclosure have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the disclosure including those disclosed in the accompanying claims.
The various embodiments described above can be combined to provide further embodiments. Aspects of the embodiments can be modified, if necessary to employ concepts of the various embodiments to provide yet further embodiments.
These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2023-0197303 | Dec 2023 | KR | national |
