Patent ID: 7678567

Claim:
An optical biosensor comprising: a light source; a first grating diffracting an incident light emitted from the light source; a total reflection plate interposed between the light source and the first grating, including a glass layer and a silicone oxide layer provided on a surface of the glass layer, so as to totally internally reflect and transmit a diffracted light diffracted by the first grating; a second grating diffracting a transmitted light transmitted within the total reflection plate and outputting a diffracted light diffracted by the second grating to the outside of the total reflection plate; a light receiving element receiving the diffracted light diffracted by the second grating; and a sensing membrane in contact with the silicon oxide layer, that includes an enzyme and a chromogenic reagent and is provided between the first grating and the second grating on the total reflection plate, wherein the first grating and the second grating are in contact with the silicon oxide layer of the total reflection plate, and the diffracted light diffracted by the first grating is internally reflected between a bottom of the glass layer and a top surface of the silicon oxide layer.