Footwear article with pressure sensor

Abstract

An article of footwear including a pressure sensor arranged in the sole structure, where the sensor includes elongated pressure-sensing cells, each of which has an axis of main extension, each cell having a first and a second carrier film, which are attached to one another by a spacer film having an elongated opening oriented along the axis of main extension, as well as a first and a second electrode on the first and the second carrier film, respectively, where the electrodes are arranged in facing relationship with each other, so that a contact area between them increases with increasing pressure, and an electrically insulating layer is arranged within the opening having a shape such that it locally prevents direct contact between the electrodes where the insulating layer is present and enables the direct contact where it is absent, where the shape is constant or repetitionary along the axis of main extension of the cell.

1 . An article of footwear, comprising a sole structure for supporting a wearer's foot and an upper for holding the wearer's foot onto the sole structure, wherein said article of footwear comprises a pressure sensor arranged in said sole structure for measuring a pressure exerted by the wearer's foot on the sole structure, said pressure sensor comprising one or more elongated pressure-sensing cells, each of said pressure sensing cells having an axis of main extension and comprising
 a first flexible carrier film and a second flexible carrier film, said first and second carrier films being attached to one another by a spacer film having an elongated opening oriented along said axis of main extension,   a first electrode arranged on said first carrier film and a second electrode arranged on said second carrier film, at least one of said first and second electrodes made of resistive material, said first and second electrodes being arranged in facing relationship with each other in said opening in such a way that said first and second electrodes may be brought into contact with each other when pressure is exerted on said pressure-sensing cell and that a contact area between said first and second electrode increases with increasing pressure,   wherein an electrically insulating layer is arranged within the opening of said spacer, said electrically insulating layer having a shape so as to locally prevent a direct contact between said first and second electrodes where said electrically insulating layer is present and to enable said direct contact where said electrically insulating layer is absent, said shape being constant or repetitionary along said axis of main extension.   
     
     
         2 . Article of footwear as claimed in  claim 1 , wherein said one or more elongated sensor cells are located in said sole structure in areas expected to be subjected to pressure peaks when the wearer is standing still, is walking or is running. 
     
     
         3 . Article of footwear as claimed in  claim 1 , wherein each of said one or more elongated sensor cells is located in an area corresponding to a bone or part of bone of a wearer's foot selected from the heel bone, the head of the first metatarsal bone, the head of the fourth or fifth metatarsal bone, the head of the second or third metatarsal bone and the head of the first phalange. 
     
     
         4 . Article of footwear as claimed in  claim 3 , wherein the axis of main extension of each cell is oriented along a vertical projection onto the sole structure of an axis of main extension of the bone to which it corresponds. 
     
     
         5 . Article of footwear as claimed in  claim 1 , wherein each of said pressure sensing cells is oval, elliptical or rectangular with rounded angles. 
     
     
         6 . Article of footwear as claimed in  claim 1 , wherein the shape of said electrically insulating layer comprises a sequence of generally triangular tooth portions arranged in the manner of a toothed rack in parallel with said axis of main extension. 
     
     
         7 . Article of footwear as claimed in  claim 1 , wherein one of said first and second electrodes that is made of resistive material is made of graphite. 
     
     
         8 . Article of footwear as claimed in  claim 1 , wherein said electrically insulating layer is made of electrically insulating ink. 
     
     
         9 . Article of footwear as claimed in  claim 1 , wherein each of said pressure sensing cells comprises a ventilation hole, in communication with the exterior or a gas reservoir, for equalization of gas pressure inside said opening. 
     
     
         10 . Article of footwear as claimed in  claim 1 , wherein said sole structure comprises an insole, said pressure sensor being arranged on or in said insole. 
     
     
         11 . Article of footwear as claimed in any one of  claim 1 , wherein said sole structure comprises a midsole, said pressure sensor being arranged on or in said midsole. 
     
     
         12 . Article of footwear as claimed in  claim 1 , wherein said one or more pressure-sensing cells are at least two pressure-sensing cells, and wherein said pressure sensor comprises one or more connection strips interconnecting said at least two pressure sensing cells, said one or more connection strips being integrally formed with said at least two pressure sensing cells, and said one or more connection strips bearing conductors for connecting the first and second electrodes of each pressure-sensing cell with an electronic control module. 
     
     
         13 . Article of footwear as claimed in  claim 12 , wherein at least one of said connection strips has a serpentine shape. 
     
     
         14 . Article of footwear as claimed in  claim 1 , wherein said article of footwear is a sports shoe. 
     
     
         15 . A pressure sensor for an article of footwear, comprising a flexible multilayer film structure that includes a forefoot portion, a heel portion and a connection strip that connects the forefoot portion to the heel portion, the connection strip being integrally formed with the multilayer film structure, wherein the pressure sensor further comprises a trough-shaped receptacle for an electronic control module, which receptacle the connection strip is arranged across and bonded to. 
     
     
         16 . Article of footwear as claimed in  claim 1 , wherein the first and second electrodes comprise a plurality of generally triangular portions, which protrude in interdigitating manner from long sides of the pressure-sensing cell into the opening so as to form a repetitionary pattern along the axis of main extension and wherein the electrically insulating layer comprises a plurality of separate, spindle-shaped portions, each of which is arranged so as to cover areas, in which sides of neighbouring triangular portions of the first electrode run alongside one another.