Patent Publication Number: US-2021181884-A1

Title: Pressure sensing touch module and manufacture method thereof

Description:
FIELD OF INVENTION 
     The present invention relates to field of touch technologies, and more particularly to a pressure sensing touch module and a manufacture method thereof. 
     BACKGROUND OF INVENTION 
     At present, with rapid development of display technology, touch displays have spread all over people&#39;s lives. With rapid development of portable electronic terminal devices, especially mobile phones and tablet technologies, pressure sensing touch technology has received extensive attention in the field of display technology. With the pressure sensing touch technology, the portable electronic terminal devices not only can recognize a position where a user touches, but also sense strength of the touch pressure. 
     At present, the portable electronic terminal device has a touch function, but a physical home button (for returning to the desktop) setting on the terminal device occupies a certain area on the touch display screen, thereby reducing display area of the touch display screen and affecting display performance. 
     In summary, the physical home button on the existing portable electronic terminal device affects the screen ratio of the display area, thereby affecting the display performance. 
     SUMMARY OF INVENTION 
     The present invention provides a pressure sensing touch module to solve the problem that the physical home button on the existing touch display screen affects the screen ratio of the display area. 
     In order to solve the above-mentioned problems, the technical solutions provided by the present invention are as follows: 
     The present invention provides a pressure sensing touch module, including: a buffer layer; a substrate disposed on the buffer layer, a touch sensing layer disposed on the substrate, the touch sensing layer configured to sense a position and a strength of a touch pressure applied to the touch sensing layer; an insulating layer disposed on the touch sensing layer; a first adhesive layer disposed between the buffer layer and the substrate; and a second adhesive layer disposed on a surface of the insulating layer, wherein the touch sensing layer is made of a silver nanofiber material. 
     In one embodiment of the present invention, an overall thickness of the pressure sensing touch module is 0.13-0.17 mm. 
     In one embodiment of the present invention, the touch sensing layer comprises a plurality of patterned lines, a line width of each of the patterned lines is 7-9 μm, and a vertical distance between the patterned lines is 7-9 μm. 
     In one embodiment of the present invention, a thickness of the touch sensing layer is 7-13 μm. 
     In one embodiment of the present invention, the substrate is made of a polyimide material. 
     The present invention further provides a pressure sensing touch module, including: a buffer layer; a substrate disposed on the buffer layer; a touch sensing layer disposed on the substrate, the touch sensing layer configured to sense a position and a strength of a touch pressure applied to the touch sensing layer; and an insulating layer disposed on the touch sensing layer. 
     In one embodiment of the present invention, the pressure sensing touch module further comprises a first adhesive layer and a second adhesive layer, the first adhesive layer disposed between the buffer layer and the substrate, the second adhesive layer disposed on a surface of the insulating layer. 
     In one embodiment of the present invention, an overall thickness of the pressure sensing touch module is 0.13-0.17 mm. 
     In one embodiment of the present invention, the touch sensing layer comprises a plurality of patterned lines, a line width of each of the patterned lines is 7-9 μm, and a vertical distance between the patterned lines is 7-9 μm. 
     In one embodiment of the present invention, the touch sensing layer is made of a silver nanofiber material. 
     In one embodiment of the present invention, a thickness of the touch sensing layer is 7-13 μm. 
     In one embodiment of the present invention, the buffer layer is made of a foam material. 
     In one embodiment of the present invention, the first adhesive layer and the second adhesive layer are both made of an optical adhesive. 
     In one embodiment of the present invention, the substrate is made of a polyimide material. 
     The present invention further provides a manufacture method of a pressure sensing touch module including: 
     step S 10 , forming a first adhesive layer on a buffer layer; 
     step S 20 , disposing a substrate on a surface of a first adhesive layer; 
     step S 30 , forming a touch sensing layer on a surface of the substrate; 
     step S 40 , forming an insulating layer on a surface of the touch sensing layer, and the insulating layer covering the touch sensing layer; and 
     step S 50 , forming a second adhesive layer on a surface of the insulating layer. 
     In one embodiment of the present invention, the step S 30  includes steps of: 
     step S 301 , depositing a nano silver film on the surface of the substrate; 
     step S 302 , coating a photoresist on a surface of the nano silver film, exposing and developing the photoresist to from a photoresist retention region and a photoresist removal region; 
     step S 303 , etching the nano silver film to form a plurality of patterned lines; 
     step S 304 , striping the photoresist to form the touch sensing layer. 
     In one embodiment of the present invention, a line width of each patterned line is 7-9 μm, and a vertical distance between the patterned lines is 7-9 μm. 
     In one embodiment of the present invention, a thickness of the touch sensing layer is 7-13 μm. 
     In one embodiment of the present invention, the first adhesive layer and the second adhesive layer are both made of an optical adhesive. 
     In one embodiment of the present invention, the buffer layer is made of a foam material. 
     The beneficial effect of the present invention: the present invention provides a pressure sensing touch module for sensing the position and a strength of a touch pressure applied to the touch sensing layer, in order to replace the physical home button on the touch display screen to improve the aspect ratio of the display area on the touch display screen. 
    
    
     
       DESCRIPTION OF DRAWINGS 
       In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the following drawings, which are intended to be used in the description of the embodiments or the prior art, will be briefly described. It will be apparent that the drawings and the following description are only some embodiments of the present invention. Those of ordinary skill in the art may, without creative efforts, derive other drawings from these drawings. 
         FIG. 1  is schematic structural view of a pressure sensing touch module according to a preferred embodiment 1 of the present invention. 
         FIG. 2  is a flowchart showing the steps of manufacture method of a pressure sensing touch module of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top”, “bottom”, “front”, “back”, “left”, “right”, “inside”, “outside”, “side”, etc., is used with reference to the orientation of the figure(s) being described. As such, the directional terminology is used for purposes of illustration and is in no way limiting. Throughout this specification and in the drawings like parts will be referred to by the same reference numerals. 
     The present invention is directed to the existing touch display screen. Due to the physical home button set on the touch display screen, a part of the area of the display screen cannot be used as a display area, which affects the screen ratio of the display area, thereby affecting the technical problem of display. The embodiments of the present invention can solve the drawback. 
     As shown in  FIG. 1 , the present invention provides a pressure sensing module, including: a buffer layer  11 , a first adhesive layer  12 , a substrate  13 , a touch sensing layer  14 , an insulating layer  15 , and a second adhesive layer  16 . The first adhesive layer  12  is disposed on the buffer layer  11 . The substrate  13  disposed on the buffer layer  12 . The touch sensing layer  14  disposed on a surface of the substrate  13 . The insulating layer  15  is disposed on the touch sensing layer  14 . The second adhesive layer  16  is disposed on the insulating layer  15 . 
     An overall thickness of the pressure sensing touch module is 0.13-0.17 mm. Each layer of the pressure sensing touch module is made of an organic polymer material. The pressure sensing touch module is attached to the backside of the OLED display layer, and the buffer layer  11  contacts with the middle frame of the whole display device as a support. 
     The buffer layer  11  mainly serves as a buffering function to prevent the display screen from affecting the touch sensing layer  14  when the display screen deformed in operation. The buffer layer  11  is made of a foam material having a relatively high density, and the foam material has the characteristics of good elasticity, light in weight and thin in volume. 
     The first adhesive layer and the second adhesive layer function as a connection. The first adhesive layer is used to connect the substrate  13  and the buffer layer  11 . The second adhesive layer is used to connect the upper surface of the pressure sensing touch module with other components of the touch display screen. The first adhesive layer and the second adhesive layer are both made of an optical clear adhesive (OCA). The OCA has the characteristics of high light transmittance and high adhesion, and the OCA does not cause problems of yellowing, peeling, and deterioration for a long period of use. 
     The substrate  13  is made of a polyimide material, the polyimide material has bending resistance and can deal with deformation when the touch screen is in operation. 
     A thickness of the touch sensing layer  14  is 10 μm. The touch sensing layer  14  is made of a silver nanofiber material, which has high transparency and high reliability. Forming the touch sensing layer  14  on the surface of the substrate  13  by a mask process. The benefit of using the mask process is that the patterned lines of the silver nanofiber on the touch sensing layer  14  can be brought to the required accuracy. The line width of each of the patterned lines of the silver nanofiber is 8 μm, and a vertical distance between the patterned lines of the silver nanofiber is 8 μm. 
     As shown in  FIG. 2 , the present invention further provides a manufacture method of a pressure sensing touch module, including the following steps: 
     Step S 10 , forming a first adhesive layer  12  on a buffer layer  11 . 
     Wherein the buffer layer  11  mainly serves as a buffering function to prevent the display screen from affecting the touch sensing layer  14  when the display screen deformed in operation. The buffer layer  11  is made of a foam material having a relatively high density, and the foam material has the characteristics of good elasticity, light in weight, and thin in volume. 
     Step S 20 , disposing a substrate  13  on a surface of a first adhesive layer. 
     Wherein the substrate  13  is made of a polyimide material, the polyimide material has bending resistance and can deal with deformation when the touch screen is in operation. 
     Step S 30 , forming a touch sensing layer  14  on a surface of the substrate  13 . 
     First, after the steps of cleaning the silver nanofiber with water, ultrasonic cleaning, and chemical cleaning, depositing nano silver film on the surface of the substrate by magnetron sputtering. Then, coating a photoresist on the surface of the nano silver film, exposing and developing the photoresist to retain the photoresist which is illuminated by the light and to remove the photoresist which is non-illuminated by the light. And etching the nano silver film to form the touch sensing layer  14  and to obtain a plurality of patterned lines of the silver nanofiber. Finally, stripping the photoresist. 
     Wherein, a thickness of the touch sensing layer  14  is 10 μm. The line width of each of the patterned lines of the silver nanofiber is 8 μm, and a vertical distance between the patterned lines of the silver nanofiber is 8 μm. 
     Step S 40 , forming an insulating layer  15  on a surface of the touch sensing layer  14 , and the insulating layer  15  covering the touch sensing layer  14 . 
     Wherein, the insulating layer  15  is made of an organic insulating material, the insulating layer  15  is used to protect the touch sensing layer  14 . 
     Step S 50 , forming a second adhesive layer  16  on a surface of the insulating layer  15 . 
     An overall thickness of the pressure sensing touch module is 0.13-0.17 mm. The pressure sensing touch module is attached to the backside of the OLED, and the buffer layer  11  contacts with the middle frame of the whole display device. The pressure sensing touch module can be fabricated using the same manufacturing process according to different display screen sizes. 
     The beneficial effect: the present invention provides a pressure sensing touch module for sensing the position and a strength of a touch pressure applied to the touch sensing layer, in order to replace the physical home button on the touch display screen to improve the aspect ratio of the display area on the touch display screen. 
     In view of the above, although the present invention has been disclosed by way of preferred embodiments, the above preferred embodiments are not intended to limit the present invention, and one of ordinary skill in the art, without departing from the spirit and scope of the invention, the scope of protection of the present invention is defined by the scope of the claims.