Patent ID: 6875175
Filing Date: 2005-04-05
Classification: A61B

Abstract:
1. In a non-contact tonometer having a cylinder defining a compression chamber, a piston movable in a forward direction along a stroke axis relative to said cylinder for compressing fluid within said compression chamber, drive means operatively connected to said piston for forcing said piston in said forward direction, energizing means for supplying current to said drive means, a fluid discharge tube in flow communication with said compression chamber for directing a fluid pulse along a test axis, and a pressure sensor arranged to provide a pressure signal associated with said fluid pulse, the improvement comprising: said energizing means being selectively operable in a plurality of different modes for controlling the pressure versus time behavior of said pressure signal, wherein said drive means comprises a proportional solenoid and wherein said plurality of different modes includes a standard mode wherein said energizing means increases current to said proportional solenoid until said energizing means shuts off current to said proportional solenoid.