Browse Prior Art Database

Optical Micrometer

IP.com Disclosure Number: IPCOM000079453D
Original Publication Date: 1973-Jul-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Malin, JR: AUTHOR

Abstract

Most devices using reflected light to measure height are qualitative and not quantitative. The device described herein is a quantitative device.

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Optical Micrometer

Most devices using reflected light to measure height are qualitative and not quantitative. The device described herein is a quantitative device.

Light from bulb 1 is divided by mirrors 2 and 3, collimated by lenses 4 and 5 and chopped by rotating disk 13 which is driven by motor 6. When a hole in disk 13 is allowing light to pass through path A, light is blocked at path B. As the disk rotates, the light is alternately switched between paths A and B.

Light path A is reflected by mirror 7 and passes through beam splitter 8 to reflect off mirror 9. Lens 14 focuses the beam just in front of the object 11 to be measured. Light path B follows a similar course being reflected by beam splitter 8, reflected by mirror 9, and focused by lens 14 just behind the object 11 to be measured.

Light is reflected from object 11 to be measured and focused on photodetector 10 by lens 14. A hole in mirror 9 allows the reflected light to pass.

As the object 11 to be measured is moved closer to the focal point of light path A, the intensity of the reflected light increases due to the increased flux density. Conversely, the light intensity from path B reflected from the object to be measured is reduced in intensity as the flux density decreases.

The logic differentiates between the two light paths and compares the relative intensity of both light paths. A voltage output is then generated proportional to the position of the object between the two focal points.

An optical...