Pen tip position detector

US4888710A · kind A · utility

Assignee

• AMETEK, INC. · US

Inventors

• John C. Venthem · Georgetown, US
• James A. Parnell · Austin, US
• Mark G. Hill · Austin, US
• Dan R. Poole · Austin, US

Key dates

• Filing date: Dec 11, 1987
• Grant date: Dec 19, 1989
• Expiry date: Dec 11, 2007

Classification

• Technology area (CPC G): Physics
• CPC primary: G01D9/40
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Apparatus, for use in conjunction with a digital plotter incorporating controlled multiple markers to create displays, for determining the position of the markers along axes of movement, comprises a detector assembly disposed at a fixed axial position relative to the plotter, and a driver for moving a marker relative to the detector assembly. The detector assembly includes means for detecting movement of the marker relative thereto and producing signals indicative of the movement. A processor interprets the signals for determining an axial position of the marker and optionally detects and compensates for a variation in the axial position of a current marker relative to the axial position of a prior marker.