Patent ID: 8867035

Claim:
A method of producing a particle detector, wherein the particle detector comprises a substrate in which at least one through-cavity opening, delimited by an entry cross section and an exit cross section, is formed, its entry cross section being intended to be connected to a source of an air flow, said substrate supporting: optical means comprising at least one laser source and at least one waveguide, which is connected to said at least one laser source and the end of which is located in proximity to the exit cross section of said cavity, and at least one photodetector located in proximity to the exit cross section of said cavity and offset with respect to the optical axis of said optical means, in order to detect the scattered light, the method comprising the steps of: (a) depositing a first layer of a material having a first optical index n 1 on said substrate, (b) depositing a second layer of a material having a second optical index n 2 on this first layer, n 2 being greater than n 1 , (c) producing said at least one waveguide by structuring the second layer, then by depositing and structuring a third layer of a material having a third optical index n 3 , n 3 being less than n 2 , (d) producing said at least one photodetector, (e) producing said at least one laser source at one end of said at least one waveguide, (f) producing the electrical interconnections between the various elements produced on the substrate, and (g) by etching in the substrate, producing said at least one through-cavity opening in proximity to an opposite end of said at least one waveguide from the laser source and in proximity to the said at least one photodetector, the photodetector being offset with respect to an optical axis of the optical means.