The embodiments of the present disclosure relate to an array substrate, a driving method thereof, a manufacturing method thereof, and a display apparatus.
A thin film transistor-based Liquid Crystal Display (LCD) includes a plurality of pixel units. Each of the pixel units comprises a pixel electrode and a thin film transistor, wherein the thin film transistor acts as a driving element of the pixel unit. In such a pixel structure, a gate voltage Vg change from a turn-on voltage to a turn-off voltage causes a jump of a pixel voltage Vp, wherein a jump voltage is ΔVp. The existence of a jump voltage ΔVp causes poor display, such as flicker and mura of grayscales of a picture on a display screen of a display apparatus. In a conventional array substrate, the jump voltage ΔVp is reduced by, for example, reducing a gate-source overlapped area of the thin film transistor and increasing a thickness of a gate insulating layer. However, the conventional technical solution may cause problems such as breakoff of a source line and increased difficulty in manufacturing the array substrate.
At least one embodiment of the present disclosure provides an array substrate, a driving method of an array substrate, a manufacturing method of an array substrate, and a display apparatus to overcome or alleviate the above technical problems.
According to an aspect of the present disclosure, there is proposed an array substrate comprising a plurality of pixel units, each of which comprises a thin film transistor and a pixel electrode, wherein the thin film transistor comprises a gate line, a source connected to the pixel electrode, and a drain,
wherein the gate line has a first overlapped region with the source in an orthogonal projection direction perpendicular to the array substrate, and each pixel unit further comprises an additional signal line provided to have a second overlapped region with the source in the orthogonal projection direction.
In an example, the additional signal line may be substantially parallel to an extension direction of the gate line, and a distance between the additional signal line and the gate line is equal to or greater than 5 μm.
In an example, the first overlapped region may have an area equal to an area of the second overlapped region.
In an example, a length of the second overlapped region in an extension direction of the source may be in a range of 18 μm to 25 μm.
In an example, the additional signal line may be provided in the same layer as the gate line.
In an example, the additional signal line may be provided in the same layer as the pixel electrode.
According to another aspect of the present disclosure, there is further provided a display apparatus comprising the array substrate according to the embodiments of the present disclosure.
According to another aspect of the present disclosure, there is further provided a driving method of the array substrate according to the embodiments of the present disclosure, comprising:
changing a voltage applied to the additional signal line from a third voltage to a fourth voltage when a voltage applied to the gate line is changed from a first voltage to a second voltage, wherein a difference between the first voltage and the second voltage is opposite in sign to a difference between the third voltage and the forth voltage.
In an example, an absolute value of the difference between the first voltage and the second voltage may be equal to an absolute value of the difference between the third voltage and the fourth voltage.
According to another aspect of the present disclosure, there is further provided a manufacturing method of an array substrate, which may comprise:
forming a common electrode layer;
forming a gate line and a gate insulation layer;
forming an active layer, a source, and a drain; and
forming a pixel electrode,
wherein the manufacturing method further comprises forming an additional signal line.
In an example, the additional signal line may be formed to be located in the same layer as the gate line.
In an example, the additional signal line may be formed to be located in the same layer as the pixel electrode.
In an example, the additional signal line may be formed to be substantially parallel to an extension direction of the gate line, and a distance between the additional signal line and the gate line is equal to or greater than 5 μm.
In an example, the additional signal line may be formed to have an overlapped region with the source, and a length of the overlapped region in an extension direction of the source is in a range of 18 μm to 25 μm.
According to the embodiments of the present disclosure, the additional signal line is provided so that the additional signal line has an overlapped region with the source in the orthogonal projection direction perpendicular to the array substrate, so as to form an additional capacitance Cas between the additional signal line and the source. The voltage on the additional signal line is set so that when the voltage applied to the gate line suddenly changes, the voltage applied to the additional signal line changes in an opposite direction. This sudden change in the voltage on the additional signal line may be coupled to the source by the capacitance Cas, thereby compensating for the jump voltage ΔVp caused by the sudden change in the voltage on the gate line.
In order to more clearly describe the technical solutions according to the embodiments of the present disclosure or in the conventional technologies, the accompanying drawings needed to be used in the description of the embodiments will be briefly described below. Obviously, the accompanying drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, other accompanying drawings can also be obtained based on these accompanying drawings without any creative work, wherein:
In order to make the purposes, technical solutions and advantages of the embodiments of the present disclosure more clear, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present disclosure. Obviously, the embodiments described are a part of the embodiments of the present disclosure instead of all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present disclosure without contributing any creative work are within the protection scope of the present disclosure. It should be noted that throughout the accompanying drawings, the same elements are represented by the same or similar reference signs. In the following description, some specific embodiments are for illustrative purposes only and are not to be construed as limiting the present disclosure, but merely examples of the embodiments of the present disclosure. The conventional structure or construction will be omitted when it may cause confusion with the understanding of the present disclosure. It should be noted that shapes and dimensions of components in the figures do not reflect true sizes and proportions, but only illustrate contents of the embodiments of the present disclosure.
Unless otherwise defined, technical terms or scientific terms used in the embodiments of the present disclosure should be of ordinary meanings to those skilled in the art. “First”, “second” and similar words used in the embodiments of the present disclosure do not represent any order, quantity or importance, but are merely used to distinguish between different constituent parts.
In addition, it can be understood that when an element such as a layer, a film, a region or a substrate etc. is referred to as being located “on” or “below” another element, the element may be “directly” located “on” or “below” the other element, or there may also be an intermediate element therebetween. In addition, “on” or “below” only represents a relative positional relationship, and the “on” or “below” relationship may change accordingly when the element or the entire device is turned over. The present disclosure will be described herein using a relative positional relationship in which a substrate is used as an underlying layer.
In a TFT-based LCD display, a direction in which liquid crystal molecules are arranged changes under the action of an external electric field, so as to control the degree of light transmission through liquid crystal. Currently, common TFT-LCD display modes mainly comprise a vertical alignment mode, a twisted nematic mode, a planar field mode, etc. An Advanced super Dimension Switch (ADS)-type liquid crystal display controls the arrangement of liquid crystal in a liquid crystal cell by generating a planar fringe electric field between a top-layer comb electrode (a pixel electrode) and an underlying planar electrode (a common electrode) on a substrate of a TFT. For the convenience of description, the following description will be made using the ADS-type liquid crystal display. It can be understood by those skilled in the art that main features of the ADS-type liquid crystal display lie in a direction of an electric field and positioning of the pixel electrode on an upper layer of the common electrode, and a structure of the TFT device as a driving element is basically the same. Therefore, the following description is equally applicable to other types of array substrates.
It should be understood that a source and a drain of the thin film transistor used are symmetrical, and therefore the source and the drain are interchangeable. In addition, for the convenience of description, the present disclosure will be described hereinafter by taking an NPN-type transistor as an example. That is, a turn-on voltage of the thin film transistor below is at a high level, and a turn-off voltage of the thin film transistor is at a low level.
An important factor in determining the quality of switching of the TFT is the parasitic capacitance Cgs between a gate metal and a source metal. As the switching of the TFT is close to be in a transient state, when the gate voltage Vg instantly decreases from a turn-on voltage Vgh of the TFT to a turn-off voltage Vgi of the TFT, a change amount ΔVg of Vg is coupled to the pixel electrode by the parasitic capacitance Cgs of the TFT, which causes the pixel voltage Vp to jump with a jump amount of ΔVp, which is called a jump voltage. Due to the presence of the jump voltage ΔVp, the pixel voltage becomes (Vp−ΔVp).
According to the principle of charge conservation, a theoretical formula of ΔVp can be obtained according to an equation (1) below.
In order to suppress the jump voltage ΔVp, Cgs may be decreased.
According to an embodiment of the present disclosure, there is provided an array substrate. The array substrate comprises a plurality of pixel units, each of which comprises a thin film transistor and a pixel electrode, wherein the thin film transistor comprises a gate line, a source connected to the pixel electrode, and a drain, wherein the gate line has a first overlapped region with the source in an orthogonal projection direction, and each pixel unit further comprises an additional signal line provided to have a second overlapped region with the source in the orthogonal projection direction.
In
As shown in
When the turn-on voltage Vgh is applied to the gate line 503a, the active layer 505 is in a turn-on state, and a voltage of a signal on the data line is transferred to the pixel electrode 5081 via a path of the drain 506a→the active layer 505→the source 506b→the pixel electrode layer 508. When the turn-off voltage Vgl is applied to the gate line 503a, the active layer 505 is in a turn-off state, and only weak leakage current flows through the active layer 505 at this time.
In the first embodiment shown in
For example, a length of the additional signal line 503c may be set to be equal to or greater than a length of the gate line 503a. For example, a thickness of the additional signal line 503c may be set to be the same as the gate line 503a. A width of the additional signal line 503c may be determined according to factors such as a size, a pixel density PPI, power consumption, transmittance, etc. of the array substrate. The additional signal line 503c has a second overlapped region with the source 506b in the orthogonal projection direction, and a length of the second overlapped region in an extension direction of the source 506b may be set in a range of 18 μm to 25 μm and, for example, may be set to 20 μm.
In the first embodiment shown in
In
In the second embodiment shown in
A length of the additional signal line 703c may be set to be equal to or greater than a length of the gate line 703a. For example, a thickness of the additional signal line 703c may be set to be the same as the pixel electrode 7081. A width of the additional signal line 703c may be determined according to factors such as a size, a pixel density PPI, power consumption, transmittance etc. of the array substrate. The additional signal line 703c has a second overlapped region with the source 706b in the orthogonal projection direction, and a length of the second overlapped region in an extension direction of the source 706b may be set in a range of 18 μm to 25 μm and, for example, may be set to 20 μm.
According to the embodiments of the present disclosure, there is also provided a driving method of an array substrate according to an embodiment of the present disclosure.
In step 901, a voltage applied to an additional signal line is changed from a third voltage to a fourth voltage while a voltage applied to a gate line is changed from a first voltage to a second voltage.
For example, a difference between the first voltage and the second voltage may be opposite to a difference between the third voltage and the fourth voltage in sign. In addition, an absolute value of the difference between the first voltage and the second voltage may be equal to an absolute value of the difference between the third voltage and the fourth voltage.
In the array substrate according to an embodiment of the present disclosure, the gate voltage Vg may be directly applied to the additional signal line after being inverted. At this time, the third voltage has the same amplitude as the first voltage, and the fourth voltage has the same amplitude as the second voltage. The gate voltage Vg may also be inverted and amplified, and is then applied to the additional signal line. The voltage Va may also be determined according to a ratio of an area of the first overlapped region between the source and the gate line in the orthogonal projection direction with relative to an area of the second overlapped region between the source and the additional signal line in the orthogonal projection direction. If the area of the second overlapped region is greater than the area of the first overlapped region, a coupling effect of the second overlapped region on the pixel voltage Vp is stronger, and amplitude of the voltage Va may be set to be smaller, and vice versa. Generally, amplitude of the gate voltage Vg ranges from −10V to +30V, and the amplitude of the voltage Va may be set correspondingly according to the amplitude of the gate voltage Vg.
The embodiments of the present disclosure further provide a manufacturing method of an array substrate. It should be noted that serial numbers of various steps in the following method are merely used as a representation of respective steps for the convenience of description, and should not be construed as indicating an execution order of the various steps. Unless explicitly stated, the method needs not to be performed exactly in the order shown. The manufacturing method of an array substrate according to an embodiment of the present disclosure may comprise forming a common electrode layer; forming a gate line and a gate insulating layer; forming an active layer, a source and a drain; and forming a pixel electrode.
Next, the manufacturing method of an array substrate according to an embodiment of the present disclosure will be described in detail with reference to
In step 1101, a common electrode layer is formed, for example, on an array side of the array substrate. For example, the common electrode layer may be formed by process steps such as deposition or sputtering, masking, wet etching, etc. The common electrode layer may generally be formed using a transparent conductive material (for example, Indium Tin Oxide (ITO), graphene, etc.) The common electrode layer may have a sheet structure.
In step 1103, a gate line and an additional signal line are formed. For example, the gate line and the additional signal line may be formed by process steps such as deposition or sputtering, masking, wet etching etc. The gate line and the additional signal line may generally be formed using a metal material (for example, copper, aluminum, etc.) The additional signal line may be formed to be substantially parallel to an extension direction of the gate line, and a distance between the additional signal line and the gate line is equal to or greater than 5 μm. The additional signal line may be formed to have a length equal to or greater than a length of the gate line. A gate insulating layer may further be formed. For example, the gate insulating layer may be formed by a process such as deposition (for example, Plasma Enhanced Chemical Vapor Deposition (PECVD)) etc. The gate insulating layer may have a thickness of, for example, about 500 nm. The gate insulating layer may generally be formed using a material such as silicon nitride (for example, SiNx).
In step 1105, an active layer, a source, and a drain of the thin film transistor are formed. For example, the source and the drain of the thin film transistor may be formed by process steps such as deposition or sputtering, masking (for example, halftone masking), etching etc., to manufacture the thin film transistor. The active layer, the source, and the drain may be formed using a semiconductor material such as amorphous silicon, oxide, Low Temperature Poly Silicon (LTPS) etc. A data line may further be formed using a metal material such as copper or aluminum.
In step 1107, a pixel electrode is formed. For example, the pixel electrode may be formed by process steps such as deposition or sputtering, masking, wet etching, etc. The pixel electrode may generally be formed by using a transparent conductive material (for example, ITO, graphene, etc.), and the pixel electrode may be connected to the source or the drain of the thin film transistor. The pixel electrode may be formed to have a strip shape.
For example, the additional signal line may be formed to have an overlapped region with the source, and a length of the overlapped region in an extension direction of the source is in a range of 18 μm to 25 μm.
In step 1201, a common electrode layer is formed, for example, on an array side of the array substrate. For example, the common electrode layer may be formed by process steps such as deposition or sputtering, masking, wet etching, etc. The common electrode layer may generally be formed using a transparent conductive material (for example, ITO or graphene). The common electrode layer may have a sheet structure.
In step 1203, a gate line and a gate insulating layer are formed. For example, the gate line may be formed by process steps such as deposition or sputtering, masking, wet etching etc. The gate line may generally be formed using a metal material (for example, copper, aluminum, etc.) A common electrode line may further be formed at the same time. A gate insulating layer may further be formed. For example, the gate insulating layer may be formed by a process such as deposition (for example, PECVD) etc. The gate insulating layer may have a thickness of, for example, about 500 nm. The gate insulating layer may generally be formed using a material such as silicon nitride (for example, SiNx).
In step 1205, an active layer, a source, and a drain of the thin film transistor are formed. For example, the source and the drain of the thin film transistor may be formed by process steps, such as deposition or sputtering, masking (for example, halftone masking), etching etc. to manufacture the thin film transistor. The active layer, the source, and the drain may be formed using a semiconductor material such as amorphous silicon, oxide, LTPS etc. A data line may further be formed using a metal material such as copper or aluminum etc.
In step 1207, a pixel electrode and an additional signal line are formed. For example, the pixel electrode and the additional signal line may be formed by process steps such as deposition or sputtering, masking, wet etching etc. The pixel electrode and the additional signal line may generally be formed using a transparent conductive material (for example, ITO or graphene) The additional signal line may be formed to be substantially parallel to an extension direction of the gate line. The additional signal line may be formed to have a length equal to or greater than a length of the gate line and be spaced apart from the pixel electrode.
For example, the additional signal line may be formed to have an overlapped region with the source, and a length of the overlapped region in the extension direction of the source is in a range of 18 μm to 25 μm.
The embodiments of the present disclosure further provide a display apparatus including the array substrate according to the embodiment of the present disclosure as described above. The display apparatus may be any product or component having a display function such as an electronic paper, a mobile phone, a tablet computer, a television, a display, a notebook computer, a digital photo frame, a navigator, etc.
According to the embodiments of the present disclosure, the additional signal line is provided so that the additional signal line has an overlapped region with the source in the orthogonal projection direction, so as to form an additional capacitance Cas between the additional signal line and the source. The voltage on the additional signal line is set so that when the voltage applied to the gate line suddenly changes, the voltage applied to the additional signal line changes in an opposite direction. This sudden change in the voltage on the additional signal line may be coupled to the source by the capacitance Cas, thereby compensating for the jump voltage ΔVp caused by the sudden change in the voltage on the gate line.
Although the present disclosure has been specifically shown and described with reference to exemplary embodiments thereof, it should be understood by those of ordinary skill in the art that various changes can be made to these embodiments in form and detail without departing from the spirit and scope of the present disclosure as defined by the appended claims.
Number | Date | Country | Kind |
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201710030511.1 | Jan 2017 | CN | national |
This application is a Section 371 National Stage Application of International Application No. PCT/CN2017/098836, filed on Aug. 24, 2017, entitled “ARRAY SUBSTRATE AND DRIVING METHOD THEREOF, MANUFACTURING METHOD AND DISPLAY APPARATUS,” which claims priority to the Chinese Patent Application No. 201710030511.1, filed on Jan. 16, 2017, incorporated herein by reference in their entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/CN2017/098836 | 8/24/2017 | WO | 00 |