Patent Publication Number: US-2022229506-A1

Title: Display panel and manufacturing method thereof

Description:
FIELD OF INVENTION 
     The present disclosure relates to the field of display technologies, and more particularly, to a display panel and a manufacturing method thereof. 
     BACKGROUND OF INVENTION 
     In the case that full screen mobile phones have been widely used, in-screen fingerprint recognition technology has become a key technology in the consumer electronics field due to its convenient identity authentication operation. Optical under-display fingerprint recognition is mainly used in current in-screen fingerprint recognition technology, which uses light-emitting pixels of organic light-emitting diode (OLED) displays as light sources and uses micro lens of fingerprint modules to read reflected light of a fingerprint and convert it into electric signals, thereby reading a fingerprint image. However, attaching external fingerprint recognition modules requires mechanical materials such as buffer foam and copper heat sinks to be hollowed out, which occupies whole machine structural space and adds additional product cost. 
     Technical problem: an objective of the present disclosure is to solve technical problems of high cost and great thicknesses of display devices caused by current display devices requiring to attach external fingerprint recognition modules. 
     SUMMARY OF INVENTION 
     To realize the above objective, the present disclosure provides a display panel having a fingerprint recognition area and a touch control area surrounding the fingerprint recognition area and including: a substrate layer; an encapsulation layer disposed on one side surface of the substrate layer; a first conductive layer having a plurality of metal meshes and first connecting lines; and a second conductive layer having a plurality of transparent conductive units and second connecting lines, wherein each of the transparent conductive units is correspondingly disposed on the metal meshes; wherein in the fingerprint recognition area, the transparent conductive units of each row are connected to form first electrodes by the second connecting lines, and the transparent conductive units of each column are bridged to form second electrodes by the first connecting lines; or the transparent conductive units of each column are connected to form the first electrodes by the second connecting lines, and the transparent conductive units of each row are bridged to form the second electrodes by the first connecting lines. 
     Further, each of the metal meshes surrounds one pixel, and each of the transparent conductive units covers the pixel. 
     Further, smaller sizes of pixels surrounded by the metal meshes indicate wider line widths of the metal meshes corresponding to the pixels. 
     Further, the metal meshes among adjacent pixels in the fingerprint recognition area are independent from each other, and the metal meshes among the pixels in the touch control area have commonly-owned parts. 
     Further, a shape of the metal meshes in the fingerprint recognition area is different from a shape of the metal meshes in the touch control area. 
     Further, in the touch control area, the metal meshes of each row are connected to form the first electrodes by the first connecting lines, and the metal meshes of each column are bridged to form the second electrodes by the second connecting lines; or the metal meshes of each column are connected to form the first electrodes by the first connecting lines, and the metal meshes of each row are bridged to form the second electrodes by the second connecting lines. 
     Further, the second conductive layer uses a composite structure of ITO/Ag/ITO, and the first conductive layer uses a composite structure of Ti/Al/Ti. 
     Further, the display panel further includes an insulating layer disposed between the first conductive layer and the second conductive layer. 
     To realize the above objective, the present disclosure further provides a manufacturing method of a display panel, which includes following steps: providing a substrate layer provided with an encapsulation layer; manufacturing a plurality of metal meshes and first connecting lines on an upper surface of the encapsulation layer to form a first conductive layer; and manufacturing a plurality of transparent conductive units and second connecting lines on an upper surface of the first conductive layer to form a second conductive layer, and forming a fingerprint recognition area and a touch control area; wherein in the fingerprint recognition area, the transparent conductive units of each row are connected to form first electrodes by the second connecting lines, and the transparent conductive units of each column are bridged to form second electrodes by the first connecting lines; or the transparent conductive units of each column are connected to form the first electrodes by the second connecting lines, and the transparent conductive units of each row are bridged to form the second electrodes by the first connecting lines. 
     Further, after the step of manufacturing the plurality of transparent conductive units and second connecting lines on the upper surface of the first conductive layer to form the second conductive layer, the manufacturing method of the display panel further includes: manufacturing an insulating layer on the upper surface of the first conductive layer; and manufacturing a plurality of contact holes on the insulating layer; wherein in the touch control area, the metal meshes of each row are connected to form the first electrodes by the first connecting lines, and the metal meshes of each column are bridged to form the second electrodes by the second connecting lines; or the metal meshes of each column are connected to form the first electrodes by the first connecting lines, and the metal meshes of each row are bridged to form the second electrodes by the second connecting lines. 
     Beneficial effect: technical effects of the present disclosure are that the present disclosure uses a structural design of combining the metal meshes and the transparent electrodes, and defines the fingerprint recognition area and the touch control area on an upper surface of the encapsulation layer and on a same layer, thereby realizing integrated fingerprint recognition and touch control functions. Under premise of ensuring the fingerprint recognition and touch control functions, it is not necessary for the present disclosure to attach external fingerprint recognition modules. Therefore, product cost is reduced, and meanwhile, a thickness of the display panel is also reduced, thereby effectively improving quality of the display panel. 
    
    
     
       DESCRIPTION OF DRAWINGS 
       The technical solutions and other beneficial effects of the present disclosure will be made obvious by describing the specific embodiments of the present disclosure in detail in conjunction with the accompanying drawings. 
         FIG. 1  is a schematic top view of a display panel according to an embodiment of the present disclosure. 
         FIG. 2  is a schematic top view of a fingerprint recognition area according to an embodiment of the present disclosure. 
         FIG. 3  is a schematic cross-sectional diagram of the fingerprint recognition area according to an embodiment of the present disclosure. 
         FIG. 4  is a schematic top view of a touch control area according to an embodiment of the present disclosure. 
         FIG. 5  is a schematic cross-sectional diagram of the touch control area according to an embodiment of the present disclosure. 
         FIG. 6  is a flowchart of a manufacturing method of a display panel according to an embodiment of the present disclosure. 
     
    
    
     Elements in the drawings are designated by reference numerals listed below. 
       10 . fingerprint recognition area;  20 . touch control area; 
       11 . first conductive layer;  111 . first metal meshes;  112 . first connecting line; 
       12 . second conductive layer;  121 . first transparent conductive units;  122 . second connecting line; 
       13 . first insulating layer;  131 . first contact hole; 
       21 . first conductive layer;  211 . second metal meshes;  212 . first connecting line; 
       22 . second conductive layer;  221 . second transparent conductive units;  222 . second connecting line; 
       23 . second insulating layer;  231 . second contact hole; 
       1 . substrate layer;  2 . array layer;  3 . encapsulation layer;  210 . pixel. 
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, but not all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative efforts are within the scope of the present disclosure. 
     In the description of the present disclosure, it should be understood that terms such as “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “upper”, “lower”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counter-clockwise”, as well as derivative thereof should be construed to refer to the orientation as described or as shown in the drawings under discussion. These relative terms are for convenience of description, do not require that the present disclosure be constructed or operated in a particular orientation, and shall not be construed as causing limitations to the present disclosure. In addition, terms such as “first” and “second” are used herein for purposes of description and are not intended to indicate or imply relative importance or implicitly indicating the number of technical features indicated. Thus, features limited by “first” and “second” are intended to indicate or imply including one or more than one of these features. In the description of the present disclosure, “a plurality of” relates to two or more than two, unless otherwise specified. 
     In the description of the present disclosure, it should be noted that unless there are express rules and limitations, the terms such as “mount,” “connect,” and “bond” should be comprehended in broad sense. For example, it can mean a permanent connection, a detachable connection, or an integrated connection; it can mean a mechanical connection, an electrical connection, or can communicate with each other; it can mean a direct connection, an indirect connection by an intermediary, or an inner communication or an inter-reaction between two elements. A person skilled in the art should understand the specific meanings in the present disclosure according to specific situations. 
     In the description of the present disclosure, unless specified or limited otherwise, it should be noted that, a structure in which a first feature is “on” or “beneath” a second feature may include an embodiment in which the first feature directly contacts the second feature and may also include an embodiment in which an additional feature is formed between the first feature and the second feature so that the first feature does not directly contact the second feature. Furthermore, a first feature “on,” “above,” or “on top of” a second feature may include an embodiment in which the first feature is right “on,” “above,” or “on top of” the second feature and may also include an embodiment in which the first feature is not right “on,” “above,” or “on top of” the second feature, or just means that the first feature has a sea level elevation greater than the sea level elevation of the second feature. While first feature “beneath,” “below,” or “on bottom of” a second feature may include an embodiment in which the first feature is right “beneath,” “below,” or “on bottom of” the second feature and may also include an embodiment in which the first feature is not right “beneath,” “below,” or “on bottom of” the second feature, or just means that the first feature has a sea level elevation less than the sea level elevation of the second feature. 
     The following disclosure provides many different embodiments or examples for realizing different structures of the present disclosure. In order to simplify the present disclosure, the components and settings of a specific example are described below. Of course, they are merely examples and are not intended to limit the present disclosure. In addition, the present disclosure may repeat reference numerals and/or reference letters in different examples, which are for the purpose of simplicity and clarity, and do not indicate the relationship between the various embodiments and/or arrangements discussed. In addition, the present disclosure provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize the use of other processes and/or the use of other materials. 
     Specifically, referring to  FIGS. 1 to 5 , an embodiment of the present disclosure provides a display panel, which includes a fingerprint recognition area  10  and a touch control area  20 . The display panel also includes a substrate layer  1 , an array layer  2 , and an encapsulation layer  3 , and the fingerprint recognition area  10  and the touch control area  20  are defined on an upper surface of the encapsulation layer  3  and on a same layer. 
     The substrate layer  1  may be a flexible substrate layer or a hard substrate, which has effect of being a substrate and is not limited herein. 
     The array layer  2  is disposed on an upper surface of the substrate layer  1  and includes circuit elements such as thin film transistors and a plurality of pixels  210 . Since shapes and sizes of the pixels  210  are different, areas of light-emitting areas are not completely same, either. 
     The encapsulation layer  3  is disposed on an upper surface of the array layer  2  and is configured to block external water and oxygen from eroding the display panel, thereby preventing problems such as nonuniform display caused by water and oxygen entering the display panel. 
     As shown in  FIG. 1 , the fingerprint recognition area  10  is positioned in a lower-middle part of the display panel and is configured to identify fingerprint signals. As shown in  FIG. 2 , sensing routes in the fingerprint recognition area  10  include a first direction  100  and a second direction  200  perpendicular to the first direction  100 . In this embodiment, the first direction  100  is a horizontal direction (that is, a row direction), and the second direction  200  is a vertical direction (that is, a column direction). 
     As shown in  FIGS. 2 and 3 , the fingerprint recognition area  10  includes a first conductive layer  11 , a second conductive layer  12 , and an insulating layer  13  disposed between the first conductive layer and the second conductive layer. 
     A material of the first conductive layer  11  is a metal material, and the first conductive layer  11  includes a plurality of first metal meshes  111  and first connecting lines  112 . The first conductive layer  11  is directly disposed on an upper surface of the encapsulation layer  3  and is formed by stacking multiple layers of metal materials. In this embodiment, it is preferably a composite structure of Ti/Al/Ti. The above metal materials have good conductivity, so the first metal meshes  111  have good conductivity, thereby ensuring electrical connections between the first metal meshes  111  and first transparent conductive units  121 . 
     The first metal meshes  111  are generally square or other meshed shapes, and each of the first metal meshes  111  is disposed corresponding to each of the pixels  210  of the array layer  2  with one-to-one size matching design. Orthographic projections of the first metal meshes  111  on the substrate layer  1  surround orthographic projections of the pixels  210  on the substrate layer  1 , that is, an area surrounded by one of the first metal meshes  111  is greater than an area of one of the pixels  210 . Therefore, areas where the pixels  210  are located are avoided and normal light-emitting display of the pixels  210  is not affected. 
     The first insulating layer  13  is disposed on an upper surface of the first conductive layer  11  and has an effect to insulate most of the first conductive layer  11  from the second conductive layer  12 . The first insulating layer  13  is provided with a plurality of first contact holes  131  penetrating through the first insulating layer  13  and exposing the underneath first conductive layer  11 . The first contact holes  131  provide channels for electrical connections between the first conductive layer  11  and the second conductive layer  12 . 
     A material of the second conductive layer  12  is a transparent material, and the second conductive layer  12  is disposed on an upper surface of the first insulating layer  13 . The second conductive layer  12  includes the first transparent conductive units  121  and second connecting lines  122 . The material of the second conductive layer  12  is different from the material of the first conductive layer  11 . The second conductive layer  12  uses a composite structure of ITO/Ag/ITO, which has good light transmittance. The first transparent conductive units  121  cover areas surrounded by the first metal meshes  111  and are disposed right above the pixels  210  (referring to  FIG. 2 ). The second connecting lines  122  are disposed on the first connecting lines  112 , and each of the second connecting lines  122  is used to connect two of adjacent first transparent conductive units  121 . 
     In the first direction  100 , sensing channels thereof are divided into two layers: the first conductive layer  11  and the second conductive layer  12 . The first connecting lines  112  serve as metal bridges of the first transparent conductive units  121 , the first transparent conductive units  121  are partially disposed in the first contact holes  131 , and two of the first transparent conductive units  121  form an electrical connection by one of the first connecting lines  112 , thereby forming second electrodes, in this embodiment, forming fingerprint drive electrodes. 
     In the second direction  200 , sensing channels thereof are also divided into the two layers: the first conductive layer  11  and the second conductive layer  12 . Two of the adjacent first transparent conductive units  121  are directly connected to each other by one of the second connecting lines  122 , thereby forming first electrodes which are in contact with each other directly, in this embodiment, forming fingerprint sense electrodes. 
     A special structural design of combining metal meshes and transparent conductive units can effectively reduce impedance of channels and improve intensities of sensing signals. 
     Since the sizes of the pixels  210  surrounded by the drive electrodes of the first direction  100  and the sense electrodes of the second direction  200  in the fingerprint recognition area  10  are different, sizes of the two kinds of electrodes are also different. The smaller sizes of the pixels  210  surrounded by the first metal meshes  111  are, the wider line widths of the first metal meshes  111  corresponding to the pixels  210  are. In this embodiment, compensation and matching between impedance and area sizes of the two kinds of electrodes are realized by adjusting the line widths of the first metal meshes  111 , that is, the line widths of the first metal meshes  111  in the first direction  100  are greater than the line widths of the first metal meshes  111  in the second direction  200 , thereby ensuring intensities of mutual capacitance sensing signals and realizing high sensitive fingerprint recognition induction. 
     As shown in  FIG. 1 , the touch control area  20  surrounds the fingerprint recognition area  10 . As shown in  FIGS. 4 and 5 , the touch control area  20  includes a first conductive layer  21  and a second conductive layer  22  and a second insulating layer  23  disposed between the first conductive layer  21  and the second conductive layer  22 . 
     A material of the first conductive layer  21  is a metal material, and the first conductive layer  21  is directly disposed on the upper surface of the encapsulation layer  3  and includes a plurality of second metal meshes  211  and first connecting lines  212 . The second metal meshes  211  and the first metal meshes  111  are disposed on a same layer. The first conductive layer  21  is formed by stacking multiple layers of metal materials. In this embodiment, it is preferably the composite structure of Ti/Al/Ti. The above metal materials have good conductivity, so the first conductive layer  21  has good conductivity, thereby ensuring electrical connections between the first conductive layer  21  and the second conductive layer  22 . 
     In this embodiment, shapes of the second metal meshes  211  are different from shapes of the first metal meshes  111 . The shapes of the second metal meshes  211  are oval, and each of the second metal meshes  211  is disposed corresponding to each of the pixels  210  of the array layer  2  with one-to-one size matching design. Orthographic projections of the second metal meshes  211  on the substrate layer  1  surround the orthographic projections of the pixels  210  on the substrate layer  1 , that is, an inner diameter of the second metal meshes  211  is greater than a width of the pixels  210 . Therefore, the areas where the pixels  210  are located are avoided and the normal light-emitting display of the pixels  210  is not affected. Meanwhile, the second metal meshes  211  adopt a cut-off design (referring to  FIG. 5 ), and the second metal meshes  211  among adjacent pixels  210  have commonly-owned parts, thereby preventing short circuits between adjacent electrodes. 
     The second insulating layer  23  is disposed on an upper surface of the first conductive layer  21  and has an effect to insulate most of the first conductive layer  21  from the second conductive layer  22 . The second insulating layer  23  is provided with a plurality of second contact holes  231  penetrating through the second insulating layer  23  and exposing the underneath first conductive layer  21 . The second contact holes  231  provide channels for electrical connections between the first conductive layer  21  and the second conductive layer  22 . 
     A material of the second conductive layer  22  is a transparent material, and the second conductive layer  22  is disposed on an upper surface of the second insulating layer  23 . The second conductive layer  22  includes a plurality of second transparent conductive units  221  and second connecting lines  222 . The material of the second conductive layer  22  is different from the material of the first conductive layer  21 . The second conductive layer  22  uses the composite structure of ITO/Ag/ITO, which has good light transmittance. The second transparent conductive units  221  cover areas surrounded by the second metal meshes  211  and are disposed right above the pixels  210  (not shown in  FIG. 5 ). The second transparent conductive units  221  are in an isolated state and are auxiliary electrodes (dummy electrodes), and the auxiliary electrodes are not used for electrical connections but used to maintain optical consistency between the touch control area  20  and the fingerprint recognition area  10 . 
     In the touch control area  20 , the second connecting lines  222  serve as bridges for the second metal meshes  211  and are partially disposed in the second contact holes  231 . Two of the second metal meshes  211  form an electrical connection by one of the second connecting lines  222 . In this embodiment, the second connecting lines  222  and the second metal meshes  211  electrically connected thereto form touch control drive electrodes. 
     The special structural design of combining the metal meshes and the transparent conductive units can effectively reduce the impedance of channels and improve the intensities of sensing signals. 
     In the fingerprint recognition area  10 , the first transparent conductive units  121  of each row are connected to form the first electrodes by the second connecting lines  122 , and the first transparent conductive units  121  of each column are bridged to form the second electrodes by the first connecting lines  112 ; or the first transparent conductive units  121  of each column are connected to form the first electrodes by the second connecting lines  122 , and the first transparent conductive units  121  of each row are bridged to form the second electrodes by the first connecting lines  112 . 
     In the touch control area  20 , the second metal meshes  211  of each row are connected to form the first electrodes by the first connecting lines  212 , and the second metal meshes  211  of each column are bridged to form the second electrodes by the second connecting lines  222 ; or the second metal meshes  211  of each column are connected to form the first electrodes by the first connecting lines  212 , and the second metal meshes  211  of each row are bridged to form the second electrodes by the second connecting lines  222 . 
     The present disclosure uses a structural design of combining the metal meshes and the transparent electrodes, and defines the fingerprint recognition area  10  and the touch control area  20  on the upper surface of the encapsulation layer  3  and on a same layer, thereby realizing integrated fingerprint recognition and touch control functions. Under premise of ensuring the fingerprint recognition and touch control functions, it is not necessary for the present disclosure to attach external fingerprint recognition modules. Therefore, product cost is reduced, and meanwhile, a thickness of the display panel is also reduced, thereby effectively improving quality of the display panel. 
     As shown in  FIG. 6 , an embodiment of the present disclosure further provides a manufacturing method of a display panel, which includes steps S 1  to S 5 . 
     S 1 : providing a substrate layer provided with an encapsulation layer. An array layer and the encapsulation layer are disposed on the substrate layer in sequence, and a plurality of light-emitting pixels are disposed in the array layer and form a plurality of light-emitting areas. 
     S 2 : manufacturing a plurality of metal meshes and first connecting lines on an upper surface of the encapsulation layer to form a first conductive layer. The metal meshes include a plurality of first metal meshes and second metal meshes. The first metal meshes are square meshed structures, and the second metal meshes are oval meshed structures and have a cut-off design. The first metal meshes are disposed on a lower-middle part of entire encapsulation layer, and an area where the second metal meshes are located surrounds an area where the first metal meshes are located. 
     S 3 : manufacturing an insulating layer on an upper surface of the first conductive layer to have insulating effect. 
     S 4 : manufacturing a plurality of contact holes on the insulating layer, which includes first contact holes and second contact holes. Wherein, the first contact holes are disposed in the area where the first metal meshes are located, the second contact holes are disposed in the area where the second metal meshes are located, and the contact holes serve as electrical connection channels between the metal meshes and transparent electrodes. 
     S 5 : manufacturing a plurality of transparent conductive units and second connecting lines on an upper surface of the insulating layer to form a second conductive layer. 
     The first transparent conductive units are disposed in the area where the first metal meshes are located, the first transparent conductive units and the first metal meshes are all disposed above the light-emitting areas, and areas of orthographic projections thereof on the substrate layer are greater than areas of orthographic projections of the light-emitting areas on the substrate layer, thereby ensuring normal light-emitting display of the light-emitting pixels in the light-emitting areas. Wherein, the first connecting lines serve as metal bridges to connect two of disconnected first transparent conductive units through the first contact holes, thereby forming sensing channels, which are located in the fingerprint recognition area. 
     The second transparent conductive units are disposed in the area where the second metal meshes are located, the second transparent conductive units and the second metal meshes are all disposed above the light-emitting areas, and areas of orthographic projections thereof on the substrate layer are greater than the areas of orthographic projections of the light-emitting areas on the substrate layer, thereby ensuring normal light-emitting display of the light-emitting pixels in the light-emitting areas. Wherein, the second connecting lines serve as bridges to connect two of disconnected second metal meshes through the second contact holes, thereby forming sensing channels, which are located in the touch control area. 
     The fingerprint recognition area and the touch control area are manufactured on the upper surface of the encapsulation layer at a same time, and both the fingerprint recognition area and the touch control area adopt a structural design of combining the metal meshes and the transparent electrodes, thereby realizing integrated fingerprint recognition and touch control functions. Under premise of ensuring the fingerprint recognition and touch control functions, it is not necessary for the present disclosure to attach external fingerprint recognition modules. Therefore, product cost is reduced, and meanwhile, a thickness of the display panel is also reduced, thereby effectively improving quality of the display panel. 
     In the above embodiments, the description of each embodiment has its own emphasis. For the parts that are not described in detail in an embodiment, can refer to the detailed description of other embodiments above. 
     The display panel and the manufacturing method thereof provided by the embodiments of the present disclosure are described in detail above. The specific examples are applied in the description to explain the principle and implementation of the disclosure. The description of the above embodiments is only for helping to understand the technical solution of the present disclosure and its core ideas, and it is understood that many changes and modifications to the described embodiment can be carried out without departing from the scope and the spirit of the disclosure that is intended to be limited only by the appended claims.