Patent Publication Number: US-2019187826-A1

Title: Touch display substrate, manufacturing method thereof and touch display device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Chinese Patent Application No. 201711338273.7 filed on Dec. 14, 2017, which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present disclosure relates to the field of display technology, in particular to a touch display substrate, a manufacturing method thereof and a touch display device. 
     BACKGROUND 
     Along with the rising of the information society and the development of the science and technology, more and more display technologies have been proposed, e.g., a conventional liquid crystal display technology, an organic light-emitting diode (OLED) display technology, and an electrophoretic display technology. As compared with the other display devices, an OLED display device has such advantages as self-luminescence, rapid response, high brightness value and wide viewing angle. In addition, for the OLED display technology, it is unnecessary to form a liquid crystal layer, so it is able to provide a flexible display device which may be curled, folded or even worn by a user. Therefore, the flexible display device is a good portable product. 
     An OLED touch display device is provided with a touch function, and a touch operation may be made by a finger or stylus intuitively and conveniently, so the OLED touch display device has been widely used in smart terminals and wearable devices. As compared with an on-cell OLED touch display device, an in-cell OLED touch display device has such advantages as being light and thin as well as low manufacture cost, so it has attracted more and more attentions. 
     For a conventional in-cell OLED touch display device, usually a touch electrode layer is formed on a package plate of an OLED element. There is a too large distance between the touch electrode layer and a touch display surface of the OLED touch display device, so touch sensitivity may be adversely affected. In addition, a display signal transmission layer is arranged between a touch signal transmission layer and the finger, so interference may easily occur. 
     SUMMARY 
     In one aspect, the present disclosure provides in some embodiments a touch display substrate, including a transparent base substrate, and a touch electrode layer, a thin film transistor (TFT) functional layer and an OLED layer arranged on the base substrate. The OLED layer is configured to emit light toward the base substrate, and the touch electrode layer is arranged between the base substrate and the OLED layer. 
     In a possible embodiment of the present disclosure, the OLED layer includes an anode layer, a cathode layer and an organic layer arranged between the anode layer and the cathode layer. The anode layer is arranged at a side of the touch electrode layer away from the base substrate, the touch electrode layer is arranged between the anode layer and the TFT functional layer, and the cathode layer is arranged at a side of the anode layer away from the touch electrode layer. 
     In a possible embodiment of the present disclosure, the anode layer is a transparent electrode layer and is multiplexed as a common electrode, the cathode layer includes a plurality of cathodes arranged in an array form, and each of the cathodes is electrically connected to a drain electrode of a TFT at the TFT functional layer and is multiplexed as a pixel electrode. 
     In a possible embodiment of the present disclosure, the TFT functional layer, the touch electrode layer and the OLED layer are stacked sequentially on the base substrate. 
     In a possible embodiment of the present disclosure, the touch electrode layer, the TFT functional layer and the OLED layer are stacked sequentially on the base substrate. 
     In a possible embodiment of the present disclosure, the organic layer includes a light-emitting layer configured to emit light beams in three-primary colors. 
     In a possible embodiment of the present disclosure, the touch display substrate further includes a cover plate arranged opposite to the base substrate and a sealant frame arranged between the base substrate and the cover plate. A sealed cavity is defined by the base substrate, the cover plate and the sealant frame, and the TFT functional layer, the touch electrode layer and the OLED layer are inside the sealed cavity. 
     In another aspect, the present disclosure provides in some embodiments a touch display device including the above-mentioned touch display substrate. 
     In a possible embodiment of the present disclosure, the touch display substrate further includes a cover plate arranged opposite to a base substrate and a sealant frame arranged between the base substrate and the cover plate. A sealed cavity is defined by the base substrate, the cover plate and the sealant frame, and a TFT functional layer, a touch electrode layer and an OLED layer are inside the sealed cavity. 
     In a possible embodiment of the present disclosure, the touch display device further includes a circuit board arranged on the base substrate, the OLED layer and the TFT functional layer each is electrically connected to a first connection region of the circuit board, and the touch electrode layer is electrically connected to a second connection region of the circuit board different from the first connection region. 
     In a possible embodiment of the present disclosure, the sealant frame is attached onto a middle portion of the circuit board in such a manner that a part of the circuit board is inside the sealed cavity and another part of the circuit board extends beyond the sealed cavity and is connected to a driving unit. The touch electrode layer, the TFT functional layer and the OLED layer each is electrically connected to the circuit board. 
     In a possible embodiment of the present disclosure, the first connection region and the second connection region are arranged at two opposite sides of the circuit board respectively. 
     In a possible embodiment of the present disclosure, an insulation layer is arranged at a side of the touch electrode layer away from the base substrate and provided with a hollowed-out structure at a position adjacent to the circuit board, and a pin of the touch electrode layer extends through the hollowed-out structure and is connected to the second connection region of the circuit board. 
     In yet another aspect, the present disclosure provides in some embodiments a method for manufacturing a touch display substrate, including: providing a transparent base substrate; and forming a touch electrode layer, a TFT functional layer and an OLED layer on the base substrate, the OLED layer being configured to emit light toward the base substrate, the touch electrode layer being arranged between the base substrate and the OLED layer. 
     In a possible embodiment of the present disclosure, the method further includes sealing the touch electrode layer, the TFT functional layer and the OLED layer though a cover plate and a sealant frame in such a manner that the touch electrode layer, the TFT functional layer and the OLED layer are inside a sealed cavity defined by the base substrate, the cover plate and the sealant frame. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to illustrate the technical solutions of the present disclosure or the related art in a clearer manner, the drawings desired for the present disclosure or the related art will be described hereinafter briefly. Obviously, the following drawings merely relate to some embodiments of the present disclosure, and based on these drawings, a person skilled in the art may obtain the other drawings without any creative effort. 
         FIG. 1  is a perspective view of a touch display device according to some embodiments of the present disclosure; 
         FIG. 2  is a sectional view of a touch display substrate of the touch display device taken along line A in  FIG. 1 ; 
         FIG. 3  is a plan view of the touch display substrate of the touch display device according to some embodiments of the present disclosure; 
         FIG. 4  is an enlarged view of a portion IV in  FIG. 2 ; 
         FIG. 5  is a flow chart of a method for manufacturing the touch display substrate according to some embodiments of the present disclosure; and 
         FIGS. 6 and 7  are schematic views showing the touch display substrate during manufacturing according to some embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In order to make the objects, the technical solutions and the advantages of the present disclosure more apparent, the present disclosure will be described hereinafter in a clear and complete manner in conjunction with the drawings and embodiments. Obviously, the following embodiments merely relate to a part of, rather than all of, the embodiments of the present disclosure, and based on these embodiments, a person skilled in the art may, without any creative effort, obtain the other embodiments, which also fall within the scope of the present disclosure. 
     The present disclosure provides in some embodiments a touch display device  100  as shown in  FIG. 1  which is a perspective view of the touch display device and  FIG. 2  which is a sectional view of a touch display substrate taken along line A. The touch display device  100  includes a display region  101  and a peripheral region  102  surrounding the display region  101 . The display region  101  is mainly used to achieve a touch display function of the touch display device  100 , and the peripheral region  102  is mainly used for the formation of lines thereon. 
     The touch display device  100  includes a touch display substrate  110 . The touch display substrate  100  includes a base substrate  111 , a TFT functional layer  112 , a touch electrode layer  113 , an OLED layer  114  and a cover plate  115  superimposed one on another. In addition, the touch display substrate  110  further includes a sealant frame  116  arranged at a side of the touch display substrate  110 . The base substrate  111  is a transparent substrate. A sealed cavity is formed by the base substrate  111 , the cover plate  115  and the sealant frame  116 , and the TFT functional layer  112 , the touch electrode  113  and the OLED layer  114  are arranged inside the sealed cavity. 
     The TFT functional layer  112  is arranged between the base substrate  111  and the OLED layer  114 , and the touch electrode  113  is arranged between the base substrate  111  and the OLED layer  114 . To be specific, the touch electrode layer  113  is arranged between the TFT functional layer  112  and the OLED layer  114 . 
     The OLED  114  is capable of emitting light toward the base substrate  111 , and a surface of the base substrate  111  away from the OLED layer  114  serves as a touch display surface of the touch display device  100 . 
     According to the touch display device in the embodiments of the present disclosure, the touch electrode layer  113  is arranged closer to the base substrate  111  than the OLED layer  114 , so the touch electrode layer  113  is arranged closer to the touch display surface of the touch display device  100 . As a result, it is able to reduce a distance between the touch electrode layer  113  and the touch display surface of the touch display device  100 , thereby improving the touch sensitivity of the touch display device  100 . In such a manner, during a touch display operation, a touch signal on the touch electrode layer  113  is between the a finger and a display signal on the OLED layer  114 , so it is able to prevent the display signal from interfering with the touch signal during the touch display operation, thereby further improving the touch sensitivity. 
     The above description is given in the case that the TFT functional layer  112  is arranged between the base substrate  111  and the touch electrode layer  113 . However as shown in  FIG. 3  which is a plan view of the touch display substrate, a TFT functional layer  212  is arranged between an OLED layer  214  and a touch electrode  213 , and the touch electrode layer  213  is arranged between the TFT functional layer  212  and a base substrate  211 . 
     The touch electrode layer may be of a single-layered or double-layered ITO (indium tin oxide) structure, or a metal mesh structure, which will not be particularly defined herein. 
     As shown in  FIG. 1 , the OLED layer  114  includes an anode layer  1141 , a cathode layer  1142  and an organic layer  1143  arranged between the anode layer  1141  and the cathode layer  1142 . The anode layer  1141  is arranged at a side of the touch electrode layer  113  away from the base substrate  111 , the touch electrode layer  113  is arranged between the TFT functional layer  112  and the anode layer  1141 , and the cathode layer  1142  is arranged at a side of the anode layer  1141  away from the touch electrode layer  113 . 
     In a possible embodiment of the present disclosure, the anode layer  1141  is formed into a single block, and it may be multiplexed as a common electrode of the touch display device  100 . 
     In a possible embodiment of the present disclosure, the cathode layer  1142  includes a plurality of cathodes (not shown) arranged independent of each other and in an array form. Each cathode may be electrically connected to a drain electrode of a TFT at the TFT functional layer  112  through via-holes in the organic layer  1143 , the anode layer  1141  and the touch electrode layer  113 . Under the control of the TFT, each cathode may be multiplexed as a pixel electrode of the touch display device  100 . 
     Here, the anode layer  1141  adjacent to the touch electrode layer  113  is formed into a single block and multiplexed as the common electrode, while the cathode layer  1142  away from the touch electrode layer  113  is formed into a plurality of blocks and multiplexed as the pixel electrodes, so a touch electrode may be arranged far away from the pixel electrode. As compared with a situation where the anode layer is formed into a plurality of blocks, it is able to reduce a magnitude of a voltage fluctuation in the case that signal interference occurs for the common electrode and prevent the common electrode from interfering with the touch electrode layer, thereby to reduce the possibility and the degree of the mutual interference between a signal in the anode layer and a signal in the touch electrode layer. 
     The organic layer  1143  further includes a light-emitting layer (not shown) for emitting light beams in three primary colors, so as to provide the touch display device  100  with a red (R)/green (G)/blue (B) light-emission mode. In addition, the organic layer  1143  may further include one or more of an electron injection layer, an electron transport layer, a hole injection layer and a hole transport layer. 
     The touch display device  100  further includes a circuit board  120  arranged on the base substrate  111 . The sealant frame  116  is attached onto a middle portion of the circuit board  120  in such a manner that a part of the circuit board  120  extends beyond the sealed cavity to be connected to an element such as a driving integrated circuit (IC) while another part of the circuit board  120  is inside the sealed cavity defined by the base substrate  111 , the cover plate  115  and the sealant frame  116 . The touch electrode layer  113 , the TFT functional layer  112  and the OLED layer  114  are each electrically connected to the circuit board  120 . 
     At the peripheral region  102  of the touch display device  100 , the OLED layer  114  and the TFT functional layer  112  are connected to a first connection region of the circuit board  120 . To be specific, the anode layer  1141  of the OLED layer  114  is connected to the first connection region of the circuit board  120 , and the cathode  1142  is connected to the first connection region of the circuit board  120  through the OLED functional layer  112 . The touch electrode layer  113  is connected, through an electrode pin of the touch electrode layer  113 , to a second connection region of the circuit board  120  different from the first connection region. 
     The first connection region and the second connection region may be arranged at two opposite sides of the circuit board  120  respectively. Of course, they may also be arranged at a same side of the circuit board  120 . 
     Through the connection of the OLED layer and the TFT functional layer to the first connection region of the circuit board and the connection of the touch electrode layer to the second connection region of the circuit board, a display signal and a touch signal may be provided in a separate manner, and a display operation and a touch operation may be performed simultaneously without any necessary to drive the touch display device in a time-division manner. As a result, it is able to use a conventional driving circuit without any necessary to provide an additional circuit, thereby to simplify the design. 
     As shown in  FIG. 4  which is an enlarged view of a portion IV in  FIG. 2 , the touch display substrate  110  further includes an insulation layer  117  arranged at a side of the touch electrode layer  113  away from the base substrate  111 . To be specific, the insulation layer  117  is arranged between the touch electrode layer  113  and the anode layer  1141 . The insulation layer  117  is provided with a hollowed-out structure  1171  at a position adjacent to the circuit board  120 , so that a pin  1131  of the touch electrode layer  113  is capable of extending through the hollowed-out structure  1171  and being connected to the second connection region of the circuit board  120 . 
     As shown in  FIG. 5 , the present disclosure further provides in some embodiments a method for manufacturing the touch display substrate  110  in  FIG. 2 , which includes the following steps  501  and  502 . 
     Step  501 : providing a transparent base substrate. To be specific, the transparent base substrate  111  may be provided, and one surface of the base substrate  111  may be a touch display surface, as shown in  FIG. 6 . 
     Step  502 : forming a touch electrode layer, a TFT functional layer and an OLED layer on the base substrate, the OLED layer being capable of emitting light toward the base substrate, the touch electrode layer being arranged between the base substrate and the OLED layer. To be specific, the TFT functional layer  112 , the touch electrode layer  113  and the OLED layer  114  may be formed on the base substrate  111 , and the touch electrode layer  113  may be arranged between the base substrate  111  and the OLED layer  114 , as shown in  FIG. 7 . Further, the TFT functional layer  112  may be arranged between the base substrate  111  and the touch electrode layer  113 , and the touch electrode layer  113  may be arranged between the TFT functional layer  112  and the OLED layer  114 . 
     The OLED layer  114  is capable of emitting light toward the base substrate  111 , and a surface of the base substrate  111  away from the OLED layer  114  serves as the touch display surface of the touch display device  100 . 
     After the formation of the touch electrode layer  113 , the insulation layer  117  may be further formed on the touch electrode layer  113 , so as to enable the touch electrode layer  113  to be insulated from the OLED layer  114 . 
     After the formation of the above layers, these layers may be placed within a sealed cavity defined by the base substrate  111 , a cover plate and a sealant frame, so as to acquire the touch display substrate in  FIG. 2 . 
     According to the touch display substrate, the manufacturing method thereof and the touch display device in the embodiments of the present disclosure, the touch display substrate includes the transparent base substrate, and the touch electrode layer, the TFT functional layer and the OLED layer arranged on the base substrate. The OLED layer is capable of emitting light toward the base substrate, and the touch electrode layer is arranged between the base substrate and the OLED layer. In this way, the touch electrode layer is arranged closer to the touch display surface of the touch display device, so as to reduce a distance between the touch electrode layer and the touch display surface of the touch display device, thereby to improve the touch sensitivity of the touch display device. In addition, the touch signal transmission layer is arranged between the finger and the display signal transmission layer, so it is able to prevent the display signal from interfering with the touch signal during the touch display operation, thereby to further improve the touch sensitivity. 
     The above are merely optional embodiments of the present disclosure, but the present disclosure is not limited thereto. Obviously, a person skilled in the art may make further modifications and improvements without departing from the spirit of the present disclosure, and these modifications and improvements shall also fall within the scope of the present disclosure.