Apparatus and methods for maintaining a substantially constant temperature in a thermal proximity sensor
US5753803A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 21, 1996 |
| Grant date | May 19, 1998 |
| Priority date | — |
| Expiry date | Nov 21, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N25/72
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Apparatus and methods for improved thermal proximity imaging are provided. A data storage medium surface is moved relative to a sensor, in one embodiment a magnetoresistive read/write element. Topographical variations on the storage medium induce temperature changes in the sensor. These temperature changes are monitored to detect the location and nature (e.g., height) of the topographical variations on the medium surface. A feedback circuit using an impedance bridge is disclosed for sensing instantaneous changes in the temperature of the sensor, correcting for the changes and, therefore, keeping the temperature of the sensor substantially constant. By keeping the temperature of the sensor constant, the topographical variations can be detected without any adverse impacts of the surrounding thermal environment on the detection response time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.