Resistive pressure sensor with improved structure design

Abstract

A transparent resistive pressure sensor and method of making the same are disclosed. The transparent resistive pressure sensor may include a flexible pressure substrate, a pressure electrode layer, an elastic dielectric spacer with microstructure, a transparent pressure-sensitive composite layer composed of a transparent polymer dielectric matrix and a conductive one-dimensional nanomaterial oriented substantially in a thickness direction of the transparent pressure-sensitive composite layer, a support electrode layer, and a support substrate, where the elastic dielectric spacer with microstructure may include a transparent elastic dielectric film and a plurality of size-varied straight holes penetrating through the transparent elastic dielectric film in a thickness direction of the transparent elastic dielectric film.

1 . A resistive pressure sensor comprising:
 a flexible pressure substrate having a pressure receiving surface and a support substrate facing surface and being parallel to a support substrate;   a pressure electrode layer disposed on the support substrate facing surface of the flexible pressure substrate;   an elastic dielectric spacer with a microstructure;   a pressure-sensitive composite layer having a first surface facing the pressure electrode layer and a second surface opposite and parallel to the first surface, wherein the pressure-sensitive composite layer comprises a conductive one-dimensional nanomaterial oriented substantially perpendicular to the first surface;   wherein the pressure-sensitive composite laver further consists of a pre-patterned structure of isolated 2-dimensional dots arrays,   a support electrode layer disposed on a pressure substrate facing surface of the support substrate and facing the pressure electrode layer; and   the support substrate,   wherein the elastic dielectric spacer with the microstructure and the pressure-sensitive composite layer are positioned between the pressure electrode layer and the support electrode layer and are optically transparent,   wherein the elastic dielectric spacer with the microstructure is attached to the first surface of the pressure-sensitive composite layer and contacts the pressure electrode layer, and the support electrode layer is attached to the second surface of the pressure-sensitive composite layer and is directly in electrical contact with the pressure-sensitive composite layer; or wherein the elastic dielectric spacer with the microstructure is attached to the second surface of the pressure-sensitive composite layer and contacts the support electrode layer, and the pressure electrode layer is attached to the first surface of the pressure-sensitive composite layer and is directly in electrical contact with the pressure-sensitive composite layer, and   wherein the elastic dielectric spacer with the microstructure comprises a transparent elastic dielectric film and a plurality of size-varied straight holes penetrating through the transparent elastic dielectric film in a thickness direction of the transparent elastic dielectric film.   
     
     
         2 . A resistive pressure sensor comprising:
 a flexible pressure substrate having a pressure receiving surface and a support substrate facing surface and being parallel to a support substrate;   a pressure electrode layer disposed on the support substrate facing surface of the flexible pressure substrate;   an elastic dielectric spacer with a microstructure;   a pressure-sensitive composite layer having a first surface facing the pressure electrode layer and a second surface opposite and parallel to the first surface, wherein the pressure-sensitive composite layer comprises a conductive one-dimensional nanomaterial oriented substantially perpendicular to the first surface;   a support electrode layer disposed on a pressure substrate facing surface of the support substrate and facing the pressure electrode layer;   wherein the support electrode layer and pressure electrode layer are further patterned into a plurality of isolated paths,   wherein the plurality of isolated paths in the support electrode layer intersect the plurality of isolated paths in the pressure electrode layer, and   the support substrate,   wherein the elastic dielectric spacer with the microstructure and the pressure-sensitive composite layer are positioned between the pressure electrode layer and the support electrode layer and are optically transparent,   wherein the elastic dielectric spacer with the microstructure is attached to the first surface of the pressure-sensitive composite layer and contacts the pressure electrode layer, and the support electrode layer is attached to the second surface of the pressure-sensitive composite layer and is directly in electrical contact with the pressure-sensitive composite layer; or wherein the elastic dielectric spacer with the microstructure is attached to the second surface of the pressure-sensitive composite layer and contacts the support electrode layer, and the pressure electrode layer is attached to the first surface of the pressure-sensitive composite layer and is directly in electrical contact with the pressure-sensitive composite layer, and   wherein the elastic dielectric spacer with the microstructure comprises a transparent elastic dielectric film and a plurality of size-varied straight holes penetrating through the transparent elastic dielectric film in a thickness direction of the transparent elastic dielectric film.   
     
     
         3 . A resistive pressure sensor comprising:
 a flexible pressure substrate having a pressure receiving surface and a support substrate facing surface and being parallel to a support substrate;   a pressure electrode layer disposed on the support substrate facing surface of the flexible pressure substrate;   an elastic dielectric spacer with a microstructure;   a pressure-sensitive composite layer having a first surface facing the pressure electrode layer and a second surface opposite and parallel to the first surface, wherein the pressure-sensitive composite layer comprises a conductive one-dimensional nanomaterial oriented substantially perpendicular to the first surface;   wherein the pressure-sensitive composite layer further consists of a pre-patterned structure of isolated paths;   a support electrode layer disposed on a pressure substrate facing surface of the support substrate and facing the pressure electrode layer;   wherein the support electrode laver and pressure electrode laver are further patterned into a plurality of isolated paths,   wherein the plurality of isolated paths in the support electrode layer intersect the plurality of isolated paths in the pressure electrode layer,   wherein the isolated paths structure of the pressure-sensitive composite layer completely overlap with the isolated paths structure of the pressure electrode layer, and   the support substrate,   wherein the elastic dielectric spacer with the microstructure and the pressure-sensitive composite layer are positioned between the pressure electrode layer and the support electrode layer and are optically transparent,   wherein the elastic dielectric spacer with the microstructure is attached to the first surface of the pressure-sensitive composite layer and contacts the pressure electrode layer, and the support electrode layer is attached to the second surface of the pressure-sensitive composite layer and is directly in electrical contact with the pressure-sensitive composite layer; or wherein the elastic dielectric spacer with the microstructure is attached to the second surface of the pressure-sensitive composite layer and contacts the support electrode layer, and the pressure electrode layer is attached to the first surface of the pressure-sensitive composite layer and is directly in electrical contact with the pressure-sensitive composite layer, and   wherein the elastic dielectric spacer with the microstructure comprises a transparent elastic dielectric film and a plurality of size-varied straight holes penetrating through the transparent elastic dielectric film in a thickness direction of the transparent elastic dielectric film.   
     
     
         4 . A resistive pressure sensor comprising:
 a flexible pressure substrate having a pressure receiving surface and a support substrate facing surface and being parallel to a support substrate;   a pressure electrode layer disposed on the support substrate facing surface of the flexible pressure substrate;   an elastic dielectric spacer with a microstructure;   a pressure-sensitive composite layer having a first surface facing the pressure electrode layer and a second surface opposite and parallel to the first surface, wherein the pressure-sensitive composite layer comprises a conductive one-dimensional nanomaterial oriented substantially perpendicular to the first surface;   wherein the pressure-sensitive composite layer further consists of a pre-patterned structure of isolated 2-dimensional dots arrays;   a support electrode layer disposed on a pressure substrate facing surface of the support substrate and facing the pressure electrode layer;   wherein the support electrode layer and pressure electrode layer are further patterned into a plurality of isolated paths,   wherein the plurality of isolated paths in the support electrode layer intersect the plurality of isolated paths in the pressure electrode layer,   wherein at least one dot of the isolated 2-dimensional dots array structure of the pressure-sensitive composite layer is located at each of the intersecting areas between the isolated paths structure of the support electrode layer and the pressure electrode layer, and   the support substrate,   wherein the elastic dielectric spacer with the microstructure and the pressure-sensitive composite layer are positioned between the pressure electrode layer and the support electrode layer and are optically transparent,   wherein the elastic dielectric spacer with the microstructure is attached to the first surface of the pressure-sensitive composite layer and contacts the pressure electrode layer, and the support electrode layer is attached to the second surface of the pressure-sensitive composite layer and is directly in electrical contact with the pressure-sensitive composite layer; or wherein the elastic dielectric spacer with the microstructure is attached to the second surface of the pressure-sensitive composite layer and contacts the support electrode layer, and the pressure electrode layer is attached to the first surface of the pressure sensitive composite layer and is directly in electrical contact with the pressure sensitive composite layer, and   wherein the elastic dielectric spacer with the microstructure comprises a transparent elastic dielectric film and a plurality of size-varied straight holes penetrating through the transparent elastic dielectric film in a thickness direction of the transparent elastic dielectric film.   
     
     
         5 . The pressure sensor of  claim 4 , wherein the 2-dimensional dots array and plurality of pre-patterned isolated paths are fabricated by laser ablation, ion beam etching, photolithography, or E-beam lithography. 
     
     
         6 . The pressure sensor of  claim 4 , wherein the pressure sensitive composite layer is prepared by spray coating and followed by curing of polymer precursors. 
     
     
         7 . The pressure sensor of  claim 4 , wherein the 2-dimensional dots array have a diameter between 1 mm and 10 mm for each dot. 
     
     
         8 . The pressure sensor of  claim 4 , wherein each of the isolated paths has a diameter between 1 mm and 10 mm. 
     
     
         9 . The pressure sensor of  claim 4 , wherein each material layer is flexible. 
     
     
         10 . The pressure sensor of  claim 4 , wherein each material layer is transparent. 
     
     
         11 . The pressure sensor of  claim 4 , wherein angle between the longitudinal axis of the conductive one-dimensional nanomaterial embedded in the pressure-sensitive composite film and the thickness direction of the pressure-sensitive composite film is in a range of 0-20 degrees. 
     
     
         12 . The pressure sensor of  claim 4 , wherein the support electrode, the pressure sensitive composite layer, and the pressure electrode are transparent. 
     
     
         13 . The pressure sensor of  claim 4 , wherein no conductive path is present between the support electrode and the pressure electrode when pressure is not applied. 
     
     
         14 . The pressure sensor of  claim 4 , wherein the conductive paths increase between the support electrode and the pressure electrode when force is applied. 
     
     
         15 . The pressure sensor of  claim 4 , wherein the conductive paths are formed via the pressure sensitive composite layer through the medium-diameter holes of the elastic dielectric layer. 
     
     
         16 . The pressure sensor of  claim 4 , wherein the amount and level of the applied force may be qualitatively and accurately measured at the location of force applied. 
     
     
         17 . The pressure sensor of  claim 4 , wherein the diameters and area ratio of the straight holes on the surface of the elastic dielectric layer can be adjusted to fine tune the detection range of pressure level and sensitivity of the resistive pressure sensor. 
     
     
         18 . The pressure sensor of  claim 4 , wherein at 60% of the conductive nanowires in the transparent polymer dielectric matrix are oriented substantially perpendicular to the first surface. 
     
     
         19 . The pressure sensor of  claim 4 , wherein the conductivity along the thickness direction is substantially higher than the conductivity in plane in the pressure sensitive composite layer. 
     
     
         20 . The pressure sensor of  claim 4 , wherein the conductive paths are formed via a few or single conductive nanowires inside the composite layer or in some instances, through electrical shorting between the pressure electrode and the support electrode caused by applied pressure.