Cursor for an inductive sensor for use with a digitizer board

US4947460A · kind A · utility

Assignee

• Kon-Tron Elektronik AG · DE

Inventors

• Wolfgang Jacob-Grinschgl · Munich, DE
• Udo Muller · Unterschleißheim, DE

Key dates

• Filing date: Mar 9, 1989
• Grant date: Aug 7, 1990
• Expiry date: Mar 9, 2009

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T29/49071
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

A transparent disk with a round periphery is produced, for example, by a grinding operation, and a mark is placed at the geometric center of the disk. A coil is then wound about the periphery of the disk. As a consequence, the mark at the geometric center of the disk coincides with the electrical center point of the coil, thus obviating the need for a bobbin, or coil former, on which the coil can be wound. The transparent disk is first ground into a round shape, and a metallic film is deposited on a surface of the disk. The film is coated with a photosensitive resist material, and then exposed through a mask to define an image of a mark at the geometric center of the disk. The film is then etched to remove all but the mark from the disk. In manufacturing the coil, the disk is concentrically clamped between two plates of a winding jig, each plate having annular peripheral flanges that are radially larger than the disk and thus project beyond the periphery of the disk. The flanges are spaced from each other to define a winding space around the periphery of the disk. A wire may then be wound on the periphery of the disk in the space between the flanges to form a coil. Thereafter, the …