Patent Publication Number: US-2022236819-A1

Title: Touch display panel and touch display device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims a priority of the Chinese patent application No. 202110117700.9 filed on Jan. 28, 2021, which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present disclosure relates to the manufacture of a display product, in particular to a touch display panel and a touch display device. 
     BACKGROUND 
     Screen-to-body ratio has become one of the main selling points for high-end mobile phones, and a display panel is required to be provided with a bezel at an increasingly small size. For a full-screen, bezel-free display product (such as mobile phone), a screen covers an entire front surface of the display product, so as to achieve a screen-to-body ratio of approximately 100%. In this way, it is able to improve the appearance of the mobile phone and provide a sense of technology. In addition, it is able to provide the mobile phone with a larger screen, so as to significantly improve the visual experience. 
     SUMMARY 
     In one aspect, the present disclosure provides in some embodiments a touch display panel, including a display region and a non-display region surrounding the display region. The non-display region includes a bonding region arranged at one side of the display region along a first direction, and a first bezel region and a second bezel region arranged respectively at two opposite sides of the bonding region along a second direction perpendicular to the first direction. The touch display panel further includes a display signal line and a touch signal line. The bonding region includes a first pad and a second pad, the display signal line is coupled to a flexible printed circuit via the first pad, the touch signal line is coupled to the flexible printed circuit via the second pad, and the second pad is arranged at one side of the first pad along the second direction. 
     In a possible embodiment of the present disclosure, the touch signal line includes a sensing signal line and a driving signal line, and the sensing signal line includes a first secondary sensing signal line extending along the first bezel region to the bonding region and a second secondary sensing signal line extending along the second bezel region to the bonding region. The first secondary sensing signal line includes a first portion arranged at the bonding region and extending along the first direction to the second pad. The second secondary sensing signal line includes a second portion, a third portion and a fourth portion arranged at the bonding region, the second portion extends along the first direction, the third portion extends from one end of the second portion, is bent and then extends along the second direction, and the fourth portion extends from one end of the third portion, is bent and then extends along the first direction to the second pad. The driving signal line is extracted from a side of the display region adjacent to the bonding region, and extends along the first direction to the second pad. 
     In a possible embodiment of the present disclosure, the bonding region includes a bending region and a non-bending region along the first direction, and the third portion is arranged at a side of the bending region adjacent to or away from the display region. 
     In a possible embodiment of the present disclosure, the touch signal line includes a sensing signal line and a driving signal line, the sensing signal line extends along the first bezel region to the bonding region and includes a fifth portion arranged at the bonding region and extending along the first direction to the second pad, the driving signal line is extracted from a side of the display region adjacent to the bonding region and includes a first secondary driving signal line and a second secondary driving signal line, the first secondary driving signal line is arranged at a side adjacent to the second pad and extends along the first direction to the second pad, the second secondary driving signal line includes a sixth portion, a seventh portion and an eighth portion, the sixth portion extends along the first direction, the seventh portion extends from one end of the sixth portion, is bent and then extends along the second direction, and the eighth portion extends from one end of the seventh portion, is bent and then extends along the first direction to the second pad. 
     In a possible embodiment of the present disclosure, the bonding region includes a bending region and a non-bending region along the first direction, and the seventh portion is arranged at a side of the bending region adjacent to or away from the display region. 
     In a possible embodiment of the present disclosure, an isolation layer is arranged between the display signal line and the touch signal line in the bonding region in a direction away from a substrate. 
     In a possible embodiment of the present disclosure, the isolation layer includes an organic material layer made of an organic material. 
     In a possible embodiment of the present disclosure, the isolation layer includes a metal shielding line with a fixed potential, and the metal shielding line is arranged at a same layer as a power source signal line of the touch display panel. 
     In a possible embodiment of the present disclosure, the isolation layer includes a metal shielding line with a fixed potential and an organic material layer arranged between the metal shielding line and the touch signal line, and the metal shielding line is arranged at a same layer as a power source signal line of the touch display panel. 
     In a possible embodiment of the present disclosure, the power source signal line serves as the metal shielding line. 
     In a possible embodiment of the present disclosure, a first inorganic insulation layer is arranged between the isolation layer and the touch signal line. 
     In a possible embodiment of the present disclosure, the touch display panel further includes a substrate, and an organic light-emitting unit and a thin film encapsulation layer laminated one on another on the substrate. A barrier layer is arranged at the non-display region in such a manner as to surround the display region, the thin film encapsulation layer includes a first region and a second region surrounding the first region, a part of the second region is arranged at a side of the barrier layer away from the substrate, a planarization layer is arranged at a side of the second region away from the substrate, and the touch signal line is extracted from the display region and extends through the planarization layer to the bonding region in the non-display region. 
     In a possible embodiment of the present disclosure, the touch display panel further includes a second inorganic insulation layer arranged at a side of the planarization layer away from the substrate. 
     In a possible embodiment of the present disclosure, a surface of the planarization layer adjacent to the bonding region is an arc-like surface. 
     In a possible embodiment of the present disclosure, an isolation layer is arranged between the display signal line and the touch signal line in the bonding region in a direction away from the substrate, and the isolation layer is arranged at a same layer, and made of a same material, as the planarization layer. 
     In a possible embodiment of the present disclosure, the planarization layer and the isolation layer are each made of an organic material. 
     In another aspect, the present disclosure provides in some embodiments a touch display device including the above-mentioned touch display panel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view showing the distribution of lines on a conventional touch display panel after the removal of a touch layer; 
         FIG. 2  is a schematic view showing the distribution of a touch signal line in the related art; 
         FIG. 3  is a schematic view showing the distribution of a touch signal line according to one embodiment of the present disclosure; 
         FIG. 4  is another schematic view showing the distribution of the touch signal line according to one embodiment of the present disclosure; 
         FIG. 5  is yet another schematic view showing the distribution of the touch signal line according to one embodiment of the present disclosure; 
         FIG. 6  is still yet another schematic view showing the distribution of the touch signal line according to one embodiment of the present disclosure; 
         FIG. 7  is a partially schematic view of the conventional touch display panel; 
         FIG. 8  is a partially schematic view of a touch display panel according to one embodiment of the present disclosure; 
         FIG. 9  is another partially schematic view of the touch display panel according to one embodiment of the present disclosure; and 
         FIG. 10  is yet another partially schematic view of a touch display panel according to one embodiment 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. 
     In the embodiments of the present disclosure, it should be appreciated that, such words as “in the middle of”, “on/above”, “under/below”, “left”, “right”, “vertical”, “horizontal”, “inside” and “outside” may be used to indicate directions or positions as viewed in the drawings, and they are merely used to facilitate the description in the present disclosure, rather than to indicate or imply that a device or member must be arranged or operated at a specific position. In addition, such words as “first”, “second” and “third” may be merely used to differentiate different components rather than to indicate or imply any importance. 
     In the design of an on-cell touch panel, usually a touch active region is greater than an active display region of the panel, i.e., an edge of a touch electrode block extends beyond the active display region. In addition, a touch signal line needs to be extracted from an upper end of a display region and extends along each of a left side and a right side of the display region to a bonding region at a lower end, is coupled to a Flexible Printed Circuit (FPC), and then is coupled to a touch integrated circuit (T-IC) via a line on the FPC. However, display signal lines are arranged in the middle of the bonding region as well as in the middle of the FPC, so the touch signal line at one side may inevitably cross the display signal line. Taking crosstalk into consideration, usually the FPC includes more than two layers, so as to shield signal interference. Hence, the manufacture cost of the FPC, in terms of process steps and materials, may increase. 
     In addition, the touch signal line is provided with a larger width due to its large distance from the bonding region, so it is difficult to reduce a size of each of a left bezel and a right bezel of the on-cell touch display panel (its size has reached a limit). There is an urgent need to provide a new design to meet the requirement on a narrow bezel. 
     As shown in  FIGS. 1 and 2 , in the related art, a touch display panel includes a display region (AA) and a non-display region surrounding the display region. The non-display region includes a bonding region arranged at one side of the display region, and bezel regions arranged respectively at two opposite sides of the bonding region. A touch signal line is extracted from the display region, and extends along a corresponding bezel region to the bonding region. A first pad  1000  bound to a display signal line  60  and a second pad  2000  bound to the touch signal line are arranged at the bezel region. Each display signal line is coupled to the FPC via the first pad  1000 , and each touch signal line is coupled to the FPC via a corresponding second pad  2000 . Two second pads  2000  are arranged at two opposite sides of the first pad  1000  respectively. As shown in  FIG. 2 , the display signal line  60  is arranged along a first direction (i.e., direction X in  FIG. 1 ), so a part of touch signal lines inevitably cross the display signal line  60 . In the related art, in order to prevent the occurrence of interference between the display signal line  60  and the touch signal line, the FPC is of a multi-layered plate-like structure, and the quantity of layers is usually greater than two. After the touch signal line has been coupled to the FPC via the corresponding second pad  2000 , it is coupled to a touch IC via a line on the FPC. Hence, the manufacture cost of the FPC, in terms of process steps and materials, may increase. 
     In order to solve the above-mentioned problems, the present disclosure provides in some embodiments a touch display panel, and a second pad  2000  bound to a touch signal line is arranged merely at a side of a first pad  1000  bound to a display signal line. In this way, it is able to reduce the quantity of lines on an FPC, and reduce the quantity of layers of the FPC, thereby to reduce the manufacture cost. 
     To be specific, the touch display panel includes a display region and a non-display region surrounding the display region. The non-display region includes a bonding region arranged at one side of the display region along a first direction, and a first bezel region and a second bezel region arranged respectively at two opposite sides of the bonding region along a second direction perpendicular to the first direction. The touch display panel further includes a display signal line and a touch signal line. The bonding region includes a first pad  1000  and a second pad  2000 , the display signal line is coupled to a flexible printed circuit via the first pad  1000 , the touch signal line is coupled to the flexible printed circuit via the second pad  2000 , the second pad  2000  is arranged at one side of the first pad along the second direction. 
     In the embodiments of the present disclosure, there are the following wiring modes. 
     In a first mode, as shown in  FIGS. 3 and 4 , the touch signal line includes a sensing signal line  101  and a driving signal line  102 , and the sensing signal line  101  includes a first secondary sensing signal line extending along the first bezel region to the bonding region and a second secondary sensing signal line extending along the second bezel region to the bonding region. The first secondary sensing signal line includes a first portion  1011  arranged at the bonding region and extending along the first direction to the second pad  2000 . The second secondary sensing signal line includes a second portion  1012 , a third portion  1013  and a fourth portion  1014  arranged at the bonding region, the second portion  1012  extends along the first direction, the third portion  1013  extends from one end of the second portion  1012 , is bent and then extends along the second direction, and the fourth portion extends from one end of the third portion  1013 , is bent and then extends along the first direction to the second pad  2000 . The driving signal line  102  is extracted from a side of the display region adjacent to the bonding region, and extends along the first direction to the second pad  2000 . 
     In this mode, the bonding region includes a bending region and a non-bending region along the first direction, and the third portion  1013  is arranged at a side of the bending region adjacent to or away from the display region. The first pad  1000  and the second pad  2000  are arranged at the non-bending region.  FIG. 3  shows a situation where the third portion  1013  is arranged at the side of the bending region away from the display region, and  FIG. 4  shows a situation where the third portion  1013  is arranged at the side of the bending region adjacent to the display region. 
     In a second mode, as shown in  FIGS. 5 and 6 , illustratively, the touch signal line includes a sensing signal line  101  and a driving signal line  102 , the sensing signal line  101  extends along the first bezel region to the bonding region and includes a fifth portion  1015  arranged at the bonding region and extending along the first direction to the second pad  200 , and the driving signal line  102  is extracted from a side of the display region adjacent to the bonding region and includes a first secondary driving signal line  1023  and a second secondary driving signal line. The first secondary driving signal line  1023  is arranged at a side adjacent to the second pad  2000  and extends along the first direction to the second pad  2000 . The second secondary driving signal line includes a sixth portion  1024 , a seventh portion  1025  and an eighth portion  1026 . The sixth portion  1024  extends along the first direction, the seventh portion  1025  extends from one end of the sixth portion  1024 , is bent and then extends along the second direction, and the eighth portion  1026  extends from one end of the seventh portion  1025 , is bent and then extends along the first direction to the second pad  2000 . 
     In this mode, the bonding region includes a bending region and a non-bending region along the first direction, and the seventh portion  1025  is arranged at a side of the bending region adjacent to or away from the display region. The first pad  1000  and the second pad  2000  are arranged at the non-bending region.  FIG. 5  shows a situation where the seventh portion  1025  is arranged at the side of the bending region away from the display region, and  FIG. 6  shows a situation where the seventh portion  1025  is arranged at the side adjacent of the bending region to the display region. 
     As shown in  FIG. 10 , illustratively, an isolation layer is arranged between the display signal line  60  and the touch signal line  100  in the bonding region in a direction away from a substrate. 
     Illustratively, the isolation layer includes an organic material layer  501  (also referred to as (overcoat layer, OC layer)) made of an organic material, such as a polymer, e.g., polyacrylate, polyimide or polycarbonate. 
     Through the organic material layer  501 , it is able to increase a distance between the display signal line  60  and the touch signal line  100  in a direction perpendicular to a substrate, thereby to prevent the occurrence of the interference between the display signal line  60  and the touch signal line  100 . 
     Illustratively, the isolation layer includes a metal shielding line  502  with a fixed potential, and the metal shielding line  502  is arranged at a same layer as a power source signal line of the touch display panel. 
     The metal shielding line  502  has a shielding effect, so it is able to prevent the occurrence of the interference between the display signal line  60  and the touch signal line  100 . 
     Illustratively, the power source signal line serves as the metal shielding line  502 . 
     As shown in  FIGS. 3-6 and 10 , in a direction away from the substrate, the touch display panel includes the display signal line  60 , the power source signal line (signal line VDD  2  and signal line VSS  3  in  FIG. 1 ) and the touch signal line  100 . The metal shielding line  502  may be provided separately, or the power source signal line of the touch display panel may serve as the metal shielding line  502 . 
     In some embodiments of the present disclosure, a width of a part of the power source signal lines in a direction parallel to the substrate increases, so that an orthogonal projection of the touch signal line  100  onto the substrate is located within the corresponding power source signal line. The power source signal line has a shielding effect, i.e., it serves as the metal shielding line. At this time, it is unnecessary to provide the metal shielding line separately, thereby to simplify the manufacture process. 
     In a specific embodiment of the present disclosure, the isolation layer includes the metal shielding line  502  and the organic material layer  501 . The organic material layer  501  is arranged between the metal shielding line  502  and the touch signal line  100 , so as to effectively prevent the occurrence of the interference between the display signal line  60  and the touch signal line  100 . 
     Illustratively, a first inorganic insulation layer  80  is arranged between the isolation layer and the touch signal line  100 , so as to protect the touch signal line  100  thereon. 
     As shown in  FIG. 7 , in the related art, the touch display panel includes to display region and a non-display region surrounding the display region. The non-display region includes a bonding region arranged at one side of the display region, and bezel regions respectively arranged at two opposite sides of the bonding region. A touch signal line is extracted from the display region, and extends along a corresponding bezel region to the bonding region. The non-display region further includes a barrier layer  10  surrounding the display region, and the touch signal line is arranged at a side of the barrier layer adjacent to the display region. Due to the touch signal line, the bezel needs to be provided with a sufficient large width. In the embodiments of the present disclosure, a planarization layer is arranged at a region of the non-display region where the barrier layer is located, and the touch signal line is arranged on the planarization layer. Hence, the barrier layer may be moved inwardly to be close to the display region, so as to reduce the width of the bezel region as a whole, thereby to provide a narrow bezel. 
     To be specific, as shown in  FIGS. 8 to 10 , the touch display panel includes a substrate, and an organic light-emitting unit and a thin film encapsulation layer  20  laminated one on another on the substrate. A barrier layer  10  is arranged at the non-display region in such a manner as to surround the display region, the thin film encapsulation layer  20  includes a first region and a second region surrounding the first region, a part of the second region is arranged at a side of the barrier layer  10  away from the substrate, a planarization layer  30  is arranged at a side of the second region away from the substrate, and the touch signal line is extracted from the display region and extends through the planarization layer  30  to the bonding region on the non-display region. 
     The thin film encapsulation layer  20  is arranged on the organic light-emitting unit, so as to prevent a light-emitting layer and other thin layers in the organic light-emitting unit from being adversely affected by external moisture and oxygen. The thin film encapsulation layer  20  includes at least one inorganic layer and at least one organic layer laminated one on another alternately. Usually, the barrier layer  10  includes a first barrier layer adjacent to the display region and a second barrier layer away from the display region. The first barrier layer functions as a stop region for the organic layer of the thin film encapsulation layer  20 , so as to define a range of the organic layer. The second barrier layer functions as to prevent cracks generated in the inorganic layer of the thin film encapsulation layer  20  from spreading to an interior of the touch display panel, thereby to prevent an encapsulation effect of the thin film encapsulation layer  20  from being deteriorated. 
     The barrier layer  10  has a certain height, so when the touch signal line  100  is arranged on the barrier layer  10 , it is easily broken, and thereby a touch defect occurs. Hence, the touch signal line  100  is arranged at a side of the barrier layer  10  adjacent to the display region, and a sufficient space needs to be reserved at the side of the barrier layer  10  adjacent to the display region for the touch signal line  100 . At this time, it is impossible to further reduce a size of the bezel region. However, in the embodiments of the present disclosure, through the planarization layer  30 , it is able to eliminate or reduce unevenness caused by the barrier layer  10  (i.e., eliminate or reduce a level difference between the first barrier layer and the second barrier layer and a level difference between the first barrier layer and the display region). The touch signal line  100  is arranged on the planarization layer  30 , and extends over the barrier layer  10  to the bonding region smoothly without any fluctuations, so it is able to ensure the reliability of the touch signal line  100 . Based on the above, as compared with  FIGS. 7, 8 and 9 , the non-display region of the touch display panel includes the bonding region and the bezel regions arranged respectively at two opposite sides of the bonding region.  FIG. 8  shows the bezel region, and  FIG. 9  shows the bonding region. In the embodiments of the present disclosure, the touch signal line  100  is arranged on the planarization layer  30 , so widths of A and B may be reduced, i.e., a width C of the barrier layer  10  adjacent to the display region may be reduced. At this time, a part of the touch signal line  100  is arranged at a region corresponding to the barrier layer  10 . As compared with a situation where the touch signal line  100  is arranged at the side of the barrier layer  10  adjacent to the display region as a whole, it is able to reduce the width of the bezel region, thereby to provide a narrow bezel. 
     In the embodiments of the present disclosure, the substrate is made of a rigid material, e.g., glass. When the substrate is a glass substrate, the touch display panel has a fixed shape. The substrate may be flexible, extendable, foldable, bendable or rollable, so as to provide a flexible, extendable, foldable, bendable or rollable touch display panel. The substrate may be made of any appropriate flexible insulation material, e.g., a polymer such as polyimide (PI), polycarbonate (PC), polyether sulfone (PES), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyarylate (PAR) or fiber reinforced plastics (FRP). The substrate may be transparent, semi-transparent or non-transparent. 
     In the embodiments of the present disclosure, the planarization layer  30  is an OC layer made of an organic material, e.g., a polymer, such as polyacrylate, PI or PC, and it may be formed through, but not limited to, an adhesive coating or printing process. 
     Illustratively, the touch display panel further includes a second inorganic insulation layer arranged at a side of the planarization layer away from the substrate. 
     Through the second inorganic insulation layer  40 , it is able to protect the touch signal line  100  thereon, thereby to prevent the occurrence of short-circuit or open-circuit. 
     Illustratively, a surface of the planarization adjacent to the bonding region is an arc-like surface. In this way, the touch signal line  100  extracted from the display region may extend to the bonding region along a smooth arc-like surface or an oblique surface, so it is able to ensure the stability of the touch signal line  100  to the greatest extend, thereby to ensure a reliable touch function. 
     In some embodiments of the present disclosure, in order to further reduce the interference between the display signal line  60  and the touch signal line  100 , an isolation layer is arranged between the display signal line and the touch signal line in the bonding region in a direction away from the substrate. In some embodiments of the present disclosure, in order to simplify the manufacture process, the isolation layer is formed at the same time with the planarization layer, i.e., the isolation layer is arranged at a same layer, and made of a same material, as the planarization layer. 
     In some embodiments of the present disclosure, the planarization layer and the isolation layer are each made of an organic material, e.g., a polymer such as polyacrylate, PI or PC, and it may be formed through, but not limited to, an adhesive coating or printing process. 
     The present disclosure further provides in some embodiments a touch display device including the above-mentioned touch display panel. The touch display device may be a mobile phone, a desk-top computer, a laptop computer, a tablet computer or an electronic photo album. The touch display device includes the above-mentioned touch display panel, so it also has the advantages of the touch display panel as mentioned hereinabove. 
     The above embodiments are for illustrative purposes only, 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.