Patent ID: 8277625

Claim:
A sheet-like gas sensing device, comprising: a first cell having a first solid electrolyte layer and first opposing electrodes formed on the front and rear faces of the first solid electrolyte layer; a first porous portion overlaid on said first cell, a hollow measuring chamber defined only by said first cell and said first porous portion, wherein gas is introduced into said hollow measuring chamber through said first porous portion, said hollow chamber communicating with one of the first opposing electrodes; a shielding layer overlaid on said first porous portion; part of an external face of said first porous portion directed toward an outermost virtual face (S 1 , S 2 , S 3 ) defined by an outermost side face of the gas sensing device, said external face of the first porous portion being located inside the outermost virtual face of the sensing device so that the part of said first porous portion is recessed from the outermost virtual face of the sensing device thereby forming a recessed cavity that includes the external face of said first porous portion, and a second porous portion having a smaller diffusion resistance than the first porous portion, a portion of said second porous portion extending into the recessed cavity and a portion of said second porous portion being disposed on said outermost side face of said gas sensing device overlaying at least an opening edge of the recessed cavity.