Patent Publication Number: US-10312231-B2

Title: Array substate and display device

Description:
TECHNICAL FIELD 
     Embodiments of the present disclosure relate to an array substrate and a display device. 
     BACKGROUND 
     At present, with constant improvement of people&#39;s living standard, display products are more and more widely applied, and people pose higher and higher demand on quality of the display products. However, the display product may be influenced by static electricity in the production, transportation and working process, and hence cannot meet the demand for high-quality display. 
     In an array substrate of an existing display device, several suspension protection capacitors generally are arranged on a signal line (a data line or a gate line) so as to prevent breakdown of the signal line due to static electricity. For example, as illustrated in  FIG. 1 , a plurality of suspension protection capacitors  10  can be arranged on a data line  103 .  FIG. 2  is a sectional view of  FIG. 1  along AA′, and illustrates the suspension protection capacitor having a structure of three layers, that is, a suspension electrode  101 , an intermediate layer  102  and the data line  103 , wherein the suspension electrode  101  can be formed along with a gate electrode of a thin film transistor, and the intermediate layer  102  usually is a gate insulating layer; and when high-voltage static electricity is existed on the data line  103 , the static electricity can be subjected to partial voltage storage by the suspension protection capacitor  10  formed between the suspension electrode  101  and the data line  103 , so as to prevent breakdown of the data line  103  due to the static electricity and guarantee a display effect of the display device. However, in such method, the data line  103  has to be used as one of the electrodes of the suspension protection capacitor  10 , which may increase a load of the data line  103  and influence normal transmission of a signal on the data line  103  so as to influence a product yield. 
     SUMMARY 
     At least one embodiment of the present disclosure provide an array substrate and a display device which can achieve protection of a signal line against static electricity and meanwhile decrease a load on the signal line, so as to improve product yield. 
     On one aspect, embodiments of the present disclosure provide an array substrate, including a first signal line, a second signal line and an electrostatic protection device, wherein the electrostatic protection device comprises a suspension Thin Film Transistor (TFT), wherein a source electrode of the suspension TFT is connected with the first signal line, a gate electrode of the suspension TFT is connected with the second signal line, and a drain electrode of the suspension TFT is suspended; and the drain electrode and the gate electrode have an overlapping region. 
     In an example, every first signal line is connected to at least two electrostatic protection devices. 
     In an example, drain electrodes of suspension TFTs in the electrostatic suspension devices connected to a same first signal line are electrically connected with each other. 
     In an example, gate electrodes of suspension TFTs in the electrostatic suspension devices connected to a same first signal line are electrically connected with each other. 
     In an example, the suspension TFT further includes an active layer arranged between the gate electrode and the drain electrode, and active layers of suspension TFTs in the electrostatic protection devices connected to a same first signal line are electrically connected with each other. 
     In an example, suspension TFTs in the electrostatic protection devices connected to two adjacent first signal lines share a same drain electrode and a same gate electrode. 
     In an example, the electrostatic protection device is connected with two adjacent first signal lines at the same time. 
     In an example, the source electrode of the suspension TFT is selected from a group consisted of a U-shaped electrode, an L-shaped electrode and a W-shaped electrode. 
     In an example, the array substrate further includes a common electrode line, wherein the second signal line is electrically connected with the common electrode line. 
     In an example, the array substrate further includes a first anti-static unit, wherein an input end of the first anti-static unit is connected with the second signal line, and an output end of the first anti-static unit is electrically connected with the common electrode line. 
     In an example, the first signal line is a gate line or a data line. 
     In an example, the array substrate further includes a second anti-static unit and a short circuit ring, wherein an input end of the second anti-static unit is connected with the first signal line, and an output end of the second anti-static unit is connected with the short circuit ring. 
     On another aspect, embodiments of the present disclosure further provide a display device, including any of the above-mentioned array substrates. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Hereafter, the embodiments of the present invention will be described in a more detailed way with reference to the accompanying drawings, so as make one person skilled in the art be able to understand the present invention more clearly, wherein: 
         FIG. 1  is a schematic diagram illustrating partial structure of a known array substrate; 
         FIG. 2  is a sectional view illustrating the structure of the known suspension capacitor; 
         FIG. 3  is a schematic diagram illustrating partial structure of an array substrate provided by an embodiment of the present disclosure; 
         FIG. 4  is a schematic diagram illustrating partial structure of an array substrate provided by another embodiment of the present disclosure; 
         FIG. 5  is a schematic diagram illustrating partial structure of an array substrate provided by yet another embodiment of the present disclosure; 
         FIG. 6  is a schematic diagram illustrating partial structure of an array substrate provided by still another embodiment of the present disclosure; 
         FIG. 7  is a schematic diagram illustrating partial structure of an array substrate provided by further another embodiment of the present disclosure; 
         FIG. 8  is an equivalent circuit diagram of B region in  FIG. 7 ; 
         FIG. 9  is a schematic diagram illustrating partial structure of an array substrate provided by yet further another embodiment of the present disclosure; 
         FIG. 10  is a schematic diagram illustrating partial structure of an array substrate provided by still further another embodiment of the present disclosure; 
         FIG. 11  is a schematic diagram illustrating partial structure of an array substrate provided by one more embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Hereafter, the technical solutions in the embodiments of the present disclosure will be described in a clearly and fully understandable way in connection with the drawings in the embodiments of the present disclosure. It is obvious that the described embodiments are just a part but not all of the embodiments of the disclosure. Based on the described embodiments herein, one person skilled in the art can obtain other embodiment(s), without any inventive work, which should be within the scope of the disclosure. 
     Unless otherwise defined, the technical terminology or scientific terminology used herein should have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Likewise, terms like “first,” “second,” etc., which are used in the description and the claims of the present application for invention, are not intended to indicate any sequence, amount or importance, but distinguish various components. The phrases “connect”, “connected”, etc., are not intended to define a physical connection or mechanical connection, but may include an electrical connection, directly or indirectly. “On,” “under,” “left,” “right” or the like is only used to describe a relative positional relationship, and when the absolute position of a described object is changed, the relative positional relationship might also be changed accordingly. 
     An embodiment of the present disclosure provides an array substrate. As illustrated in  FIG. 3 , in one example, the array substrate includes: a first signal line  31 , a second signal line  32  and an electrostatic protection device, wherein the electrostatic protection device includes a suspension thin film transistor (TFT)  33 , a source electrode  331  of the suspension TFT  33  is connected with the first signal line  31 , a gate electrode  333  of the suspension TFT  33  is connected with the second signal line  32 , and a drain electrode  332  of the suspension TFT  33  is suspended; and the drain electrode  332  and the gate electrode  333  have an overlapping region. 
     According to the embodiment of the present disclosure, the drain electrode  332  and the gate electrode  333  have an overlapping region such that when a voltage is applied on both the drain electrode  332  and the gate electrode  333 , the drain electrode  332  and the gate electrode  333  of the suspension TFT  33  can form an electrostatic storage capacitor. 
     According to the embodiment of the present disclosure, the source electrode  331  of the suspension TFT  33  is connected with the first signal line  31  such that the first signal line  31  can supply the source electrode  331  of the suspension TFT  33  with a source voltage; the gate electrode  333  of the suspension TFT  33  is connected with the second signal line  32  such that the second signal line  32  can supply the gate electrode  333  of the suspension TFT  33  with a gate voltage; and the drain electrode  332  of the suspension TFT  33  is suspended, that is, the drain electrode  332  is not electrically connected with any conductive layer. In this way, at specific times or periodically, a gate-on voltage is provided to the second signal line  32  so as to turn on the suspension TFT  33 ; at this moment, if a great amount of electrostatic charges exist on the first signal line  31 , the drain electrode  332  and the gate electrode  333  of the suspension TFT  33  form an electrostatic storage capacitor which can store the electrostatic charges on the first signal line  31 . 
     As compared to the existing array substrate, the first signal line of the array substrate provided by the embodiment of the present disclosure is connected with the suspension TFT such that the first signal line supplies the suspension TFT with the source voltage, and the second signal line supplies the suspension TFT with the gate-on voltage at specific times or periodically so as to turn on the suspension TFT. Therefore, during a turn-on period of the suspension TFT, in case that there are electrostatic charges on the first signal line, the source voltage of the suspension TFT is increased, and then the source electrode and the drain electrode of the suspension TFT are conducted; in this way, a great amount of electrostatic charges are transferred into the electrostatic storage capacitor formed by the drain electrode and the gate electrode of the suspension TFT, and electrostatic breakdown of the first signal line is prevented; in case that the second signal line provides no gate-on voltage, the suspension TFT may be turned off, and then the first signal line and the suspension TFT are in a disconnected state, so that a load of the first signal line is reduced and a normal transmission of the signal on the first signal line is guaranteed, thereby improving the product yield. 
     The embodiment of the present disclosure does not limit the specific number of the electrostatic protection devices connected on the first signal line  31  or the specific number of the suspension TFTs  33  included in the electrostatic protection device, which can be flexibly arranged by those skilled in the art through comprehensively considering factors such as electrostatic protection capacity, cost, production process and the like. 
     It should be noted that the suspension TFT in the embodiment of the present disclosure can have the same process steps with at least one type of other thin film transistors in the array substrate, e.g., the suspension TFT can be produced and completed synchronously with a switching transistor and/or a driving transistor in the array substrate by using a photoetching process; and certainly, the suspension TFT also can be prepared by adopting other process steps, such as printing. The production method of the suspension TFT is not particularly limited in the embodiment of the present disclosure, and is not repeated herein. 
     In one example, every first signal line is connected with at least two electrostatic protection devices, so that the electrostatic protection capacity for the first signal line can be further reinforced and a probability for the first signal line to be broken down by the static electricity is reduced, without increasing the load of the first signal line. In practical application, four to six electrostatic protection devices can be connected on every first signal line to implement electrostatic protection for the first signal line. 
     In one example, as illustrated in  FIG. 4 , the drain electrodes  332  of the suspension TFTs connected to a same first signal line  31  are electrically connected. 
     With reference to  FIG. 4 , the drain electrodes  332  of the suspension TFTs included in the electrostatic protection devices connected to the same first signal line  31  are connected together, so that areas of the drain electrodes  332  can be increased, thereby improving the charge storage capacity of the electrostatic storage capacitor formed by the drain electrode  332  and the gate electrode  333 . In practical production process, the areas of the drain electrodes  332  can be made as large as possible, so that the charge storage capacity of the electrostatic storage capacitor can be further improved. It should be noted that, by connecting the drain electrodes  332  of the suspension TFTs included in the electrostatic protection devices connected to the same first signal line  31  together, a relatively large drain electrode is formed, and the relatively large drain electrode is still suspended, i.e., the relatively large drain electrode is not electrically connected with any conductive layer. 
     In one example, as illustrated in  FIG. 5 , the gate electrodes  333  of the suspension TFTs connected to a same first signal line  31  are electrically connected. 
     With reference to  FIG. 5 , the gate electrodes  333  of the suspension TFTs included in the electrostatic protection devices connected to the same first signal line  31  are connected together, so that areas of the gate electrodes  333  can be increased, thereby improving the charge storage capacity of the electrostatic storage capacitor formed by the drain electrodes  332  and the gate electrodes  333 . 
     In one example, the drain electrode of the suspension TFT has a U shape, an L shape or a W shape. 
     In practical application, the source electrode of the suspension TFT can be configured to have the U shape, the L shape or the W shape, which is not particularly limited in the embodiment of the present disclosure. For example, with reference to  FIG. 3 , by configuring the drain electrode  331  of the suspension TFT  33  to have a U shape, a conduction area between the source electrode  331  and the drain electrode  332  can be increased; in this way, when a great amount of electrostatic charges on the first signal line  31  need to be transferred into the electrostatic storage capacitor formed by the drain electrode  332  and the gate electrode  333  of the suspension TFT  33 , a relatively stronger charge conduction can be established between the drain electrode  331  and the drain electrode  332 , so that a retention time of the static electricity on the first signal line  1  is reduced, thereby reducing the probability that the first signal line is broken down by the static electricity. 
     In one example, with reference to  FIG. 5 , the array substrate further includes a common electrode line  36 , wherein the second signal line  32  is electrically connected with the common electrode line  36 . By electrically connecting the second signal line  32  with the common electrode line  36 , the gate voltage can be provided to the gate electrode  333  of the suspension TFT  33  through the common electrode line  36 , which is simple and convenient to implement. 
     In one example, as illustrated in  FIG. 6 , the array substrate further includes a first anti-static unit  34 , wherein an input end of the first anti-static unit  34  is connected with the second signal line  32 , and an output end of the first anti-static unit  34  is electrically connected with the common electrode line  36 . 
     For example, the first anti-static unit  34  can have an Electro-Static Discharge (ESD) structure which generally includes a plurality of TFTs; by turning on the TFTs, the static electricity on a signal line being protected is transferred onto a dredging line so as to prevent electrostatic breakdown of the signal line being protected. 
     Therefore, by connecting the first anti-static unit  34  between the second signal line  32  and the common electrode line  36 , both the first signal line  31  and the second signal line  32  can be protected against static electricity, wherein the first signal line  31  generally is a gate line or a data line. 
     In one example, as illustrated in  FIG. 7 , the array substrate further includes a second anti-static unit  35  and a short circuit ring  37 , wherein an input end of the second anti-static unit  35  is connected with the first signal line  31 , and an output end of the second anti-static unit  35  is connected with the short circuit ring  37 . 
     For example, the second anti-static unit  35  has an ESD structure. Generally, in case that the first signal line  31  is being protected against the static electricity by using an ESD structure, since the ESD structure generally includes a plurality of TFTs, the TFTs are easily to be broken down to cause damage to the ESD structure when a great amount of static electricity exists on the first signal line  31 , so that the number of times of protection, the time last for protection and the like of the ESD structure with respect to the first signal line  31  are limited, which may influence the effect of protection against static electricity. Therefore, in this example, the first signal line  31 , on which the suspension TFT electrostatic protection device is arranged, is additionally connected with a second anti-static unit  35 , so that the suspension TFT and the ESD structure are cooperated with each other to further reinforce the capacity of protection against static electricity for the first signal line  31 . 
       FIG. 8  is an equivalent circuit diagram of a B region in  FIG. 7 . As illustrated in  FIG. 8 , the suspension TFT can be equivalent to a switching TFT with a switching effect and an electrostatic storage capacitor C. When electrostatic charges exist on the first signal line  31 , the switching TFT is turned on and a part of the electrostatic charges on the first signal line  31  are transferred to and stored in the electrostatic storage capacitor C while the other part of the electrostatic charges on the first signal line  31  are dredged onto the short circuit ring  37  through the ESD structure, thereby preventing the first signal line from being broken down by the static electricity. 
     In one example, as illustrated in  FIG. 9 , the suspension TFT  33  further includes an active layer  334  arranged between the gate electrode  333  and the drain electrode  332 , and the active layers  334  of suspension TFTs  33  connected to a same first signal line  31  are electrically connected. In this way, a production process for the active layer  334  of the suspension TFT  33  can be simplified. 
     In one example, as illustrated in  FIG. 10 , the suspension TFTs  33  connected on two adjacent first signal lines  31  share the same drain electrode  332  and the same gate electrode  333 . Therefore, the two adjacent first signal lines  31  can be protected against the static electricity at the same time, and the cost can be saved and the process can be simplified. 
     In one example, as illustrated in  FIG. 11 , the electrostatic protection device is simultaneously connected with two adjacent first signal lines  31 . Since every first signal line  31  is connected with two electrostatic protection devices, better effect of protection against the static electricity can be achieved. 
     As described above, the array substrate provided by the embodiment of the present disclosure includes the first signal line, the second signal line and the electrostatic protection device; the electrostatic protection device includes the suspension TFT, wherein the source electrode of the suspension TFT is connected with the first signal line, the gate electrode of the suspension TFT is connected with the second signal line, and the drain electrode of the suspension TFT is suspended; and the drain electrode  332  and the gate electrode  333  have an overlapping region. As compared to the existing array substrate, the first signal line of the array substrate provided by the embodiment of the present disclosure is connected with the suspension TFT such that the first signal line supplies the suspension TFT with the source voltage, and the second signal line supplies the suspension TFT with the gate-on voltage at specific times or periodically so as to turn on the suspension TFT. Therefore, during a turn-on period of the suspension TFT, in case that there are electrostatic charges on the first signal line, the source voltage of the suspension TFT is increased, and then the source electrode and the drain electrode of the suspension TFT are conducted; in this way, a great amount of electrostatic charges are transferred into the electrostatic storage capacitor formed by the drain electrode and the gate electrode of the suspension TFT, and electrostatic breakdown of the first signal line is prevented; in case that the second signal line provides no gate-on voltage, the suspension TFT may be turned off, and then the first signal line and the suspension TFT are in a disconnected state, so that a load of the first signal line is reduced and a normal transmission of the signal on the first signal line is guaranteed, thereby improving the product yield. 
     An embodiment of the present disclosure further provides a display device which includes the array substrate provided by any embodiment above. The display device can be any product or component with a display function, e.g., a liquid crystal panel, an Organic Light Emitting Diode (OLED) panel, a displayer, a television, a notebook computer, a digital photo frame, a mobile phone, a tablet personal computer, a navigator and the like, without particularly limited in the embodiments of the present disclosure. 
     The foregoing embodiments merely are exemplary embodiments of the disclosure and not intended to define the scope of the disclosure, and any variations or replacements which can be easily thought of by those skilled in the art in the technical scope of the disclosure shall fall within the scope of disclosure. Therefore, the scope of the disclosure shall be determined by the scope of the appended claims. 
     The present disclosure claims the benefits of Chinese patent application No. 201520679430.0, which was filed with the SIPO on Sep. 2, 2015 under the title of “ARRAY SUBSTRATE AND DISPLAY DEVICE” and is fully incorporated herein by reference as part of this application.