Device for measuring at least one dimension of an object and a method of operating said device
US4115702A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 25, 1977 |
| Grant date | Sep 19, 1978 |
| Priority date | — |
| Expiry date | Apr 25, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/105
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A device for measuring at least one dimension of an object comprises two light channels of which one is intended to receive the object and the other serves as a reference channel. Light from the two channels is conducted to respective photo-electric transducers the outputs of which are connected to a comparison circuit. The relationship between the relative intensities of illumination of the transducers provides a measure of the dimension of the object. In order to improve the response characteristics of the transducers they are connected in parallel with mutually reversed polarity and the difference between the electric currents passed by the two transducers is compensated by negative feedback via a resistor connected to the output of an amplifier at the input of which the said transducers are connected.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.