Angle measurement device employing angle sensor and electronics integrally formed on a printed circuit board

• US 5,381,604 A
• Filed: 05/23/1994
• Issued: 01/17/1995
• Est. Priority Date: 04/08/1993
• Status: Expired due to Term

• Current Assignee: Cline Labs, Inc.
• Original Assignee: Cline Labs, Inc.
• Inventors: Carlson, Bradley D., Heidel, Jeffrey C., Stansberry, Warren W.
• Primary Examiner(s): Wirthlin, Alvin
• Application Number:
  US08/247,923
• Time in Patent Office: 239 Days
• Field of Search: 33/366, 33/377, 340/689
• US Class Current: 33/366.21
• CPC Class Codes: G01C 9/06 Electric or photoelectric indication or reading means
• CPC Class Codes: G01C 9/20 the indication being based on the inclination of the surface of a liquid relative to its container

Abstract

An integral angle measurement device employs a printed circuit board having electronic components mounted on the front surface thereof and having a pair of sensor plates etched into the back surface thereof. Containment of the sensor fluid adjacent the sensor plates is accomplished by soldering a sensor cover to an etched sealing ring on the back of the circuit board. The sensor plates etched into the back of the printed circuit board, in combination with the sensor fluid, act as variable resistors whose resistance changes as a function of their angle of rotation from a reference position. An output signal across these variable resistors is in or out of phase with an applied reference signal. The output signal is demodulated with the same reference signal and then filtered to a DC level that corresponds to the angle of rotation. An output stage serves as a driver and also as a means for permitting the user to remotely control the electronic gain of the angle measurement device.

Claims

1. An integral resistive angle measurement device comprising:

a single printed circuit board having front and back surfaces;

a pair of sensor plates formed on the back surface of said printed circuit board;

a single cylindrically-shaped cap sealed to said back surface of said printed circuit board so as to cover said pair of sensor plates, said cap retaining a volume of resistive sensor fluid in contact with a portion of each one of said pair of sensor plates;

a metallic sealing ring surrounding said pair of sensor plates, said metallic sealing ring being electrically insulated from said pair of sensor plates, said single cylindrically-shaped cap being sealed to said metallic sealing ring by soldering; and

electronic circuitry mounted on said front surface of said printed circuit board, said electronic circuitry being responsive to incremental angular rotation of said angle measurement device for providing an output signal representative of an angle of rotation of said angle measurement device, said electronic circuitry including an output amplifier stage and gain selection circuitry for selecting one of a plurality of predetermined gain settings of said output amplifier stage, said gain selection circuitry including switching means for enabling a user to select a desired one of said plurality of predetermined gain settings of said output amplifier stage.

2. An integral angle measurment device as in claim 1 wherein each one of said pair of sensor plates is formed by etching a metallic clad layer on said back surface of said printed circuit board.