ELECTRICAL DIGITAL DISPLAY TONOMETER

• US 3,724,263 A
• Filed: 09/29/1970
• Issued: 04/03/1973
• Est. Priority Date: 09/29/1970
• Status: Expired due to Term

• Current Assignee: Bruce Jay Sand, Harold Bern Rose
• Original Assignee: Bruce Jay Sand, Harold Bern Rose
• Inventors: Rose, Harold Bern, Sand, Bruce Jay
• Primary Examiner(s): Gill, James J.
• Application Number:
  US05/076,554
• Time in Patent Office: 917 Days
• Field of Search: 73/78,80,81,84,94,313,DIG.5,105,146.5 128/2T 33/169,172,173,174,201,143L,147N,148H 324/34PS,99B,99D 340/195-199,252,336
• US Class Current: 600/399
• CPC Class Codes: A61B 3/16 for measuring intraocular pressure, e.g. tonometers

Abstract

Apparatus for measuring displacement is disclosed which includes a prehensible member including a transducer for developing an analog electrical signal whose value is a function of the displacement to be measured and digital display means for visually displaying a digital reading of such value. A stationary unit remote from the prehensible member is also provided which includes conversion means for converting the analog signal into a suitable digital signal for display in the digital display means. A flexible cord is provided interconnecting the prehensible member and the stationary unit for conducting the analog signals from the transducer to the conversion means and the digital signal from the conversion means to the digital display means.

Claims

1. A tonometer for measuring intra-ocular pressure, comprising, in combination:

a prehensible member including a transducer for developing an analog electrical signal whose value is a function of the intra-ocular pressure to be measured and digital display means for visually displaying said value, a stationary unit remote from said prehensible member including conversion means for converting an analog signal into a digital signal, and a flexible cord including a plurality of electrically conductive paths interconnecting said prehensible member and said stationary unit for conducting analog signals from said transducer to said conversion means and digital signals from said conversion means to said digital means, whereby an operator using the tonometer on a patient can simultaneously observe said digital display means and accurately position said transducer on the patient'"'"''"'"'s eyeball.

2. A tonometer according to claim 1 in which said transducer comprises two electrical coils and a movable core member magnetically coupling said coils and means for displacing said core member as a function of the intra-ocular pressure which is to be measured and which further includes an oscillator having an output signal of a predetermined frequency and magnitude located in said stationary unit and means for connecting an output signal from said oscillator through said flexible cord to one of said coils in said transducer, whereby an analog signal is developed in the other of said coils having said predetermined frequency and whose magnitude is a function of the displacement of said core.

3. A tonometer according to claim 2 in which said transducer further includes a probe adapted to be placed against a patient'"'"''"'"'s cornea and means for coupling said probe to said movable core.

4. The tonometer of claim 3 in which said transducer is movably mounted on said prehensible member to allow said transducer to move axially relative to the rest of said prehensible member.

5. The tonometer of claim 4 which further includes an amplitude demodulator located in said stationary unit for demodulating the analog signal from said transducer, means for connecting said analog signal from said transducer through said flexible cord to said demodulator, and means for connecting the output signal from said demodulator to said conversion means.

6. The tonometer of claim 5 in which said conversion means comprises a dual slope integraTor, means for connecting the output signal from said demodulator and pulses from said oscillator to said dual slope integrator, an output gate controlled by the output signal from said dual integrator, means for applying pulses from said oscillator to said output gate, whereby the signal from said output gate is a digital signal comprising a series of pulses whose number is a function of the displacement to be measured, and means for connecting said digital signal from said output gate through said flexible cord to said digital display means.

7. The tonometer of claim 6 in which said digital display means comprises a plurality of light emitting diodes arranged in a digital format and which further includes light emitting diode control means located in said prehensible member including a counter for counting the pulses in said digital signal, and means responsible to the count of said counter for energizing selected ones of said light emitting diodes.

8. The tonometer of claim 7 which further includes a movable graph and a movable recording pen located in said stationary unit , means for moving said graph whenever said tonometer is being operated, and means driven by the output signal of said demodulator for moving said recording pen.