Electromagnetic joystick using varying overlap of coils and conductive elements
US5911627A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 23, 1997 |
| Grant date | Jun 15, 1999 |
| Priority date | — |
| Expiry date | Oct 23, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05G2009/04755
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A joystick having an electromagnetic element coupled to a movable stick, with at least a pair of orthogonal coils on an underlying substrate. Alternately, the coils and electromagnetic elements can be reversed. The movement of the stick is detected by the amount of overlap of the electromagnetic element and the coils in each direction. The quality factor of the coil changes as more or less of the coil is overlapped, which can be measured by an electric circuit to determine the direction of movement and the amount of movement of the joystick. The electromagnetic element could be, for instance, a conductive steel plate, or a piece of another metal or of another conductive material, or ferrite particles. The coil could be wound (preferably on air only or, if needed to reach a higher value of inductance, on a magnetic core, provided this is small enough to not hide the effect of the mobile electromagnetic element). Or the coils could be made from traces on a printed circuit board (PCB), provided the use of a high enough (greater than 1 MHz) driving frequency, eliminating the need for a large, expensive wound coil.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.