Specification
of the effects of acoustic noise
on optical tools
Michael Gendreau
Optical Tools respond to internal vibration that
can be excited by the external acoustic environment. The degree to which this
occurs depends on many factors, but primarily the correspondence between the
resonance characteristics of the tool and the frequency content of the acoustic
environment in which it operates. Adverse noise environments, such as those
often found in laboratories and microelectronics fabrication facilities, can
affect the threshold of resolution achievable by the tool.
This paper reviews the (typically somewhat inadequate) state of noise specification
for optical tools, and the noise levels in typical spaces in which these are
intended to operate. Manufacturer's noise specifications often overstate or
underestimate the sensitivity of their tool when the noise sensitivity criterion
is oversimplified. More precise and detailed criteria would be useful, for example,
in the design of laboratories, or troubleshooting tool operational problems.
Noise & Vibration Worldwide, Multi-Science Publishing Co Ltd, UK; Vol. 32,
No. 4,
April 2001, pp. 17-22.