KR102769163B1 - Gate driver in-panel device improving operational performance related to x-axis stretch and the stretchable display device applied with the same - Google Patents

Abstract

The stretchable display device of the present invention may include a sensor that determines whether a panel is stretched and generates a signal corresponding to the tension of the panel; a processor that receives the signal from the sensor and applies a voltage to an S node; a pull-up transistor configured as a dual gate including a first gate connected to a Q node and a second gate connected to the S node; and a pull-down transistor including a gate connected to a QB node.

Description

{GATE DRIVER IN-PANEL DEVICE IMPROVING OPERATIONAL PERFORMANCE RELATED TO X-AXIS STRETCH AND THE STRETCHABLE DISPLAY DEVICE APPLIED WITH THE SAME}

The present invention relates to a stretchable display device, and more specifically, to a GIP device that improves the operating performance of a stretchable display panel when stretched in the X-axis direction, and a stretchable display device to which the GIP device is applied.

Stretchable displays are configured so that the display can be bent and stretched in various directions. Since the display is bent and stretched in various directions, there is a problem in that the GIP output characteristics deteriorate due to changes in the characteristics of the gate driver in-panel (GIP) and the TFT, resistance, and capacitance of the pixel array within the display panel.

Fig. 2 is a graph showing changes in the characteristics of an output signal within a GIP when a stretchable display panel is stretched. When the stretchable display panel is stretched, the resistance or capacitance within the pixel array may increase, and the performance of a TFT (thin-film transistor) may deteriorate.

And this increase in resistance or capacitance leads to an RC value, i.e., an output delay, as shown in Fig. 2. Accordingly, a means is required to secure the operational stability of a stretchable display panel by compensating for the deterioration of GIP output characteristics due to changes in device characteristics when the stretchable display panel is stretched.

One object of the present invention is to provide a stretchable display device that improves X-axis tensile performance.

A gate-in-panel device according to one embodiment may include a first transistor configured as a dual gate, including a first gate connected to a Q node to which a pixel operation control signal is applied and a second gate connected to an S node to which a voltage is applied when the stretchable display panel is stretched; and a second transistor connected to the QB node and the S node.

Here, the stretchable display panel may further include a tension detection sensor that detects tension and generates a voltage corresponding to the detection result and applies the voltage to the S node.

Here, for voltage bootstrapping of the Q node, a capacitor connected to the Q node may be further included.

Here, the capacitor may be configured so that the capacitance increases due to an increase in the area and a decrease in the thickness of the stretchable display panel when the stretchable display panel is stretched.

A stretchable display device according to one embodiment includes a stretchable display panel; and a gate-in-panel device controlling the display panel, wherein the gate-in-panel device may include a first transistor configured as a dual gate including a first gate connected to a Q node to which a pixel operation control signal is applied and a second gate connected to an S node to which a voltage is applied when the stretchable display panel is stretched; and a second transistor connected to the QB node and the S node.

Here, the gate-in-panel device can be placed on the rear surface of one side of the stretchable display panel.

Here, the gate-in-panel device may further include a tension detection sensor that detects tension of the stretchable display panel, generates a voltage corresponding to the detection result, and applies the voltage to the S node.

Here, the gate-in-panel device may further include a capacitor connected to the Q node for voltage bootstrapping of the Q node.

Here, the capacitor may be configured so that the capacitance increases due to an increase in the area and a decrease in the thickness of the stretchable display panel when the stretchable display panel is stretched.

According to another embodiment, a stretchable display device may include a sensor for determining whether a panel is stretched and generating a signal corresponding to the tension of the panel; a processor for receiving the signal from the sensor and applying a voltage to an S node; a pull-up transistor configured as a dual gate including a first gate connected to a Q node and a second gate connected to the S node; and a pull-down transistor including a gate connected to a QB node.

According to one embodiment of the present invention, a stretchable display device having improved X-axis tensile performance can be provided.

Figure 1 is a drawing for explaining a stretchable display panel.
Figure 2 is a graph showing the change in the characteristics of the output signal within the GIP when the stretchable display panel is stretched.
Figure 3 is an example diagram of a conventional GIP circuit for driving a stretchable display panel.
FIG. 4 is a circuit diagram of a GIP device for improving X-axis tensile performance according to one embodiment of the present invention.
FIG. 5 is a graph showing the degree of on-current improvement when an S node signal according to an X-axis tension value is added according to one embodiment of the present invention.
FIG. 6 is a graph showing a bootstrapping voltage when a strain sensor capacitor is added according to one embodiment of the present invention.
Figure 7 is a graph comparing the change in characteristics of an output signal in a conventional GIP device and a GIP device according to an embodiment of the present invention.
FIG. 8 is a graph showing the degree of improvement in the falling time of the gate output signal of the GIP device according to one embodiment of the present invention.

Since the embodiments described in this specification are intended to clearly explain the idea of the present invention to a person having ordinary skill in the art to which the present invention pertains, the present invention is not limited to the embodiments described in this specification, and the scope of the present invention should be interpreted to include modified or altered examples that do not depart from the idea of the present invention.

The terms used in this specification have been selected from commonly used terms that are as much as possible in consideration of their functions in the present invention, but this may vary depending on the intention of a person with ordinary knowledge in the technical field to which the present invention belongs, precedents, or the emergence of new technologies. However, if a specific term is defined and used with an arbitrary meaning, the meaning of that term will be described separately. Accordingly, the terms used in this specification should be interpreted based on the actual meaning of the term and the overall contents of this specification, not simply the name of the term.

The drawings attached to this specification are intended to facilitate explanation of the present invention, and shapes depicted in the drawings may be exaggerated as necessary to help understand the present invention, and therefore the present invention is not limited by the drawings.

In cases where it is determined that a specific description of a configuration or function of a known matter related to the present invention may obscure the gist of the present invention, a detailed description thereof will be omitted as necessary.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

Figure 1 is a drawing for explaining a stretchable display panel.

Referring to FIG. 1, the stretchable display panel may include an active area, a gate-in panel (GIP), and a source D-IC. FIG. 1 illustrates that the gate-in panels are arranged on both sides centered on the active area and the source D-IC is arranged at the bottom, but is not limited thereto.

The active region may include a plurality of pixels. The gate-in panel may be a control device including at least one processor for controlling the plurality of pixels. The source D-IC may provide color and luminance data within the display pixel.

Below, a GIP device that can improve the tensile operating performance of a stretchable display is described.

Fig. 3 is an example diagram of a conventional GIP circuit for driving a stretchable display panel, and Fig. 4 is a circuit diagram of a GIP device for improving X-axis tensile performance according to an embodiment of the present invention. Fig. 4 is an embodiment of the present invention, and the GIP circuit of the present invention is not limited to Fig. 4.

FIG. 5 is a graph showing the degree of on-current improvement when an S node signal according to an X-axis tensile value is added according to an embodiment of the present invention, FIG. 6 is a graph showing a bootstrapping voltage when a strain sensor capacitor is added according to an embodiment of the present invention, FIG. 8 is a graph showing a change in the characteristics of an output signal in a GIP device according to an embodiment of the present invention and a conventional GIP device, and FIG. 8 is a graph showing the degree of improvement in the falling time of a gate output signal of a GIP device according to an embodiment of the present invention.

First, Fig. 3 is a circuit diagram that shows a simplified version of a conventional GIP circuit.

The GIP circuit is configured to control pixel operation of the display panel, and a TFT (thin-film transistor) in the GIP circuit is configured to act as a switch for controlling the color and brightness of the pixel. The GIP circuit may include a pull-up TFT and a pull-down TFT. The pull-up TFT may perform a role of charging data to an LED capable of expressing a desired color by turning on a pixel connected by a HIGH voltage. On the other hand, the pull-down TFT may perform a role of maintaining a LOW voltage, thereby preventing data of a previously charged LED from leaking out, thereby maintaining the color. Here, the pull-up TFT may be referred to as a first transistor, and the pull-down TFT may be referred to as a second transistor.

Referring to FIG. 4, the present invention is configured to include a pull-up TFT configured with a dual gate structure and a pull-down TFT configured with a single gate structure in a GIP device having the structure of a pull-up TFT and a pull-down TFT.

The dual gates of the pull-up TFT can be configured to be connected to the Q node, which is connected to the TFT turned on by the G(n-2) signal and the G(n+3) signal, respectively, and to the S node, to which the voltage Vstrain received from the X-axis tension detection sensor (not shown) is applied.

Although it was previously configured with a single gate connected only to the Q node, the pull-up TFT (110) of the present invention may additionally be provided with a gate to which the voltage Vstrain of the X-axis tension detection sensor (not shown) is applied.

Here, the X-axis tensile detection sensor (not shown) is configured to detect the tensile force in the X-axis direction of the stretchable display panel (200), and may be configured to generate a voltage Vstrain corresponding to the detection result.

An X-axis tensile detection sensor (not shown) may be provided in an area where the stretchable display panel (200) can be stretched.

The X-axis tension detection sensor (not shown) can be configured to apply voltage Vstrain to the S node of the pull-up TFT (110).

The pull-up TFT (110) receives voltage only through the Q node to which a pixel operation control signal is applied when no tension is applied, but can additionally receive voltage Vstrain through the S node when tension is detected.

The pull-down TFT (120) can be configured as a single gate structure connected to the S node.

In this way, there is an advantage in that the on-current of the pull-up TFT (110) increases due to the voltage Vstrain applied to the S node when the stretchable display panel (200) is stretched. That is, Vstrain can control the gate of the pull-up TFT (110).

Figure 5 shows a timing diagram when voltage Vstrain is applied through the S node, and the degree of on-current enhancement between drain and source is graphically depicted accordingly.

Meanwhile, a strain sensor capacitor (130) may be configured to be provided between the output node Gout(n) and the Q-node of the pull-up TFT (110).

The strain sensor capacitor (130) may be configured such that when the stretchable display panel (200) is stretched, the area of the stretchable display panel (200) increases and the thickness decreases, thereby increasing the capacitance Cstrain. That is, rather than detecting the tension through a separate sensor, the capacitor structure is configured such that the capacitance Cstrain increases as the stretchable display panel (200) is stretched, thereby deforming.

In this case, a bootstrapping voltage proportional to the increased capacitance Cstrain of the strain sensor capacitor (130) is additionally generated, as in the mathematical expression 1 below.

Accordingly, as shown in Fig. 6, the voltage of the Q node increases by the bootstrapping voltage.

The voltage Vstrain applied to the S node of the dual gate mentioned above and the bootstrapping voltage generated by the strain sensor capacitor (130) cause changes in the signal characteristics within the GIP device (100), and the output signal also changes.

Figure 7 (A) shows a simulation result of signal characteristics before signal compensation by the dual gate structure and the strain sensor capacitor (130), and Figure 7 (B) shows a simulation result of signal characteristics after signal compensation by the dual gate structure and the strain sensor capacitor (130).

Specifically, Fig. 7 is a simulation result under 30% tensile conditions. Referring to Fig. 7, it can be confirmed that in the simulation result (B) compared to (A), C_strain changed by 130%, gate resistance changed by 130%, gate capacitance changed by 150%, and dual gate TFT mobility changed by 120%.

Previously, the voltage at the Q node decreased during tension and the voltage falling time was also long, but after applying the compensation circuit of the present invention, it can be seen that the voltage at the Q node increased and the falling time was significantly reduced.

In Fig. 8, when the Q-node was 1.55 ㎲ when there was no tension, the falling time increased significantly to 3.15 ㎲ when tension was applied without applying the compensation circuit. However, after applying the compensation circuit, it was confirmed that the falling time was compensated to about 94.8% of the level before tension even when tensioned.

The GIP device (100) of the present invention can be configured to detect tension in the horizontal direction, i.e., the X-axis direction.

And by applying the GIP device (100) of the present invention to a stretchable display panel (200), the effect of reducing the bezel can be achieved compared to a display panel using a gate D-IC.

A source D-IC that supplies color and brightness data within the display pixels may be provided at the lower horizontal side of the stretchable display device (200) of the present invention.

The stretchable display device of the present invention may include a sensor that determines whether a panel is stretched and generates a signal corresponding to the tension of the panel; a processor that receives the signal from the sensor and applies a voltage to an S node; a pull-up transistor configured as a dual gate including a first gate connected to a Q node and a second gate connected to the S node; and a pull-down transistor including a gate connected to a QB node.

In addition, the stretchable display device of the present invention can derive the effect of bootstrapping by connecting and arranging the C_strain between the pull-up TFT and the output node only in the area that can actually be stretched within the panel.

The present invention is a pull-up transistor in a dual-gate form, in which one of the two gates is connected to an S node that operates only when tensioned. Accordingly, when tensioned, a signal is transmitted to the top gate of the pull-up transistor, and the pull-up transistor, which is a dual-gate transistor, operates, thereby producing an effect in which the on-current increases.

Although the embodiments have been described above by way of limited examples and drawings, those skilled in the art can make various modifications and variations from the above description. For example, appropriate results can be achieved even if the described techniques are performed in a different order than the described method, and/or components of the described system, structure, device, circuit, etc. are combined or combined in a different form than the described method, or are replaced or substituted by other components or equivalents.

Therefore, other implementations, other embodiments, and equivalents to the claims are also included in the scope of the claims described below.

Claims (10)

A first transistor comprising a dual gate including a first gate connected to a Q node to which a pixel operation control signal is applied and a second gate connected to an S node to which a voltage is applied when the stretchable display panel is stretched; and
A gate of a third transistor, the drain of which is connected to the S node, and a second transistor, the gate of which is connected to the QB node, are comprised of a single gate.
Gate in panel device.
In the first paragraph,
Further comprising a tension detection sensor that detects the tension of the above stretchable display panel, generates a voltage corresponding to the detection result, and applies the voltage to the S node.
Gate in panel device.
In the first paragraph,
For voltage bootstrapping of the above Q node, a capacitor is further included that is connected to the Q node.
Gate in panel device.
In the third paragraph,
The above capacitor,
When the stretchable display panel is stretched, the capacitance is configured to increase due to an increase in the area and a decrease in the thickness of the stretchable display panel.
Gate in panel device.
Stretchable display panel; and
A gate-in panel device for controlling the above display panel is included,
The above gate-in panel device,
A first transistor comprising a dual gate including a first gate connected to a Q node to which a pixel operation control signal is applied and a second gate connected to an S node to which a voltage is applied when the stretchable display panel is stretched; and
A gate of a third transistor, the drain of which is connected to the S node, and a second transistor, the gate of which is connected to the QB node, are comprised of a single gate.
Stretchable display device.
In paragraph 5,
The above gate-in-panel device is arranged on the back side of one side of the stretchable display panel.
Stretchable display device.
In paragraph 5,
The above gate-in panel device,
Further comprising a tension detection sensor that detects the tension of the above stretchable display panel, generates a voltage corresponding to the detection result, and applies the voltage to the S node.
Stretchable display device.
In paragraph 5,
The above gate-in panel device,
For voltage bootstrapping of the above Q node, a capacitor is further included that is connected to the Q node.
Stretchable display device.
In Article 8,
The above capacitor,
When the stretchable display panel is stretched, the capacitance is configured to increase due to an increase in the area and a decrease in the thickness of the stretchable display panel.
Stretchable display device.
A sensor that determines whether the panel is stretched and generates a signal corresponding to the tension of the panel;
A processor that receives the signal from the sensor and applies voltage to the S node;
A pull-up transistor comprising a dual gate including a first gate connected to the Q node and a second gate connected to the S node; and
A third transistor - the drain of said third transistor is connected to said S node - and a pull-down transistor including a gate of a single-gate type connected to the QB node.
Stretchable display device.