The merit of using silicon for the development of hearing aid microphones and intraocular pressure sensors*

An unportant design rule for a hearmg rud 1s the reqmrement of a large stgnal to nome ratlo, wluch IS mainly determmed by that of the mIcrophone and 1t.s preampldier It ~11 be shown that m order to increase the signal to noise ratlo it IS favourable to mtegrate the preamplifier wth the rmcrophone, whtch unphes that the mIcrophone should be made of dicon, preferably with a smgle wafer technology For the development of a tonometer for the measurement of mtraocular pressure, the apphcatlon of a s&con force sensor ratlonahzes that also the flattening of the eye globe 1s measured with a sdlcon applanabon sensor, Instead of by optical means wluch IS the present practze A sensor construction has been developed, wiuch combmes a force, pressure and applanatlon sensor, all made m sdicon