Electronic tonometer with baseline nulling system

Details Electronic tonometer with baseline nulling system Electronic tonometer with baseline nulling system

1985-09-27

1988-05-31

Noland, Tom

Measuring and testing

Instrument proving or calibrating

Volume of flow, speed of flow, volume rate of flow, or mass...

73753, 128652, 324130, 330 9, 364558, G01L 2700

Patent

active

047472960

ABSTRACT:
Disclosed is a battery powered, hand-held self-contained electronic tonometer with a digital readout for displaying pressure in millimeters of mercury. The tonometer includes a transducer which is a solid state pressure sensitive element and which produces a voltage proportional to intraocular pressure. An electrical waveform is produced by gently bringing the transducer in contact with the cornea. The waveform is converted to a digital signal and processed by a single chip microprocessor. The baseline of a reference signal is nulled by equalizing the charges on two capacitors on the inputs of two differential amplifiers. Equalizing the differential inputs of the two amplifier stages results in a gain of zero and removes any carrier signal. Microprocessor software detects the baseline condition established by equalizing the differential inputs. The microprocessor then looks for a series of valid measurements and calculates the average intraocular pressure along with an estimate of reliability. This average value and the reliability indicator are displayed on a liquid crystal display.

REFERENCES:
patent: 3266288 (1966-08-01), Andresen, Jr. et al.
patent: 3366948 (1968-01-01), Price
patent: 3475600 (1969-10-01), Spence
patent: 3641444 (1972-02-01), Watts
patent: 3748587 (1973-07-01), Aumiaux
patent: 3781869 (1973-12-01), Sudnick et al.
patent: 3810031 (1974-05-01), Poujois
patent: 3884079 (1975-05-01), Turtle et al.
patent: 3889518 (1975-06-01), Denouter et al.
patent: 3924612 (1975-12-01), Dempster et al.
patent: 3926056 (1975-12-01), Brown
patent: 4003370 (1977-01-01), Emil et al.
patent: 4086804 (1978-05-01), Ruby
patent: 4088009 (1978-05-01), Fukuda
patent: 4263918 (1981-04-01), Swearingen et al.
patent: 4322977 (1982-04-01), Sell et al.
patent: 4532809 (1985-08-01), Antonazzi et al.
"Carrier Amplifier Has Zero Drift"; Electronics, vol. 25, No. 12, pp. 131-133; Dec. 1952; Angelo Perone.

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