| Summary: | 博士 === 國立臺灣大學 === 應用力學研究所 === 86 === Abstract
An innovative laser Doppler vibrometer/interferometer has been developed.
In order to improve many of the drawbacks which exist in
traditional interferometers,
a circular polarization interferometer configuration that uses two orthogonally
polarized light beams instead of an acoustic optical modulator (AOM) to remove
directional ambiguity is adopted. A built-in compact
microscope system designed
to facilitate sample alignment/focusing and measurement location identification
is also discussed. A balanced mechanical design which ensures
structural thermal
stability needed for high precision interferometry measurement is presented.
The analog and digital phase demodulating methods developed to
achieve an optimum
cost performance ratio is examined.
Interferometers represent one of the most promising
technologies to measure high
precision mechanical systems. However, most traditional
interferometers are finding
it difficult to keep up with the current high speed, high-tech
development pace and
to adapt rapidly to today''s versatile and complicated measurement situations.
To overcome the main drawbacks of traditional optical metrology instruments,
a new miniature interferometer system was developed jointly by
National Taiwan University,
Tjing-Ling Industrial Research Institute, and AHEAD Optoelectronics, Inc.
This newly developed instrument possesses the following features such as
(1) requires no modification to measurement surfaces, (2) has
an absolute/differential
detection capability, (3) is able to accommodate samples with
significantly different
reflectivity, (4) possesses nanometer resolutions, and (5) has
a mega-hertz bandwidth.
To demonstrate the nanometer measurement capabilities,
this newly developed interferometer
was adopted to many different fields. They include: (1)
vertical runout measurements and
vibration analysis of optical storage device including rotating
disks and spindles,
(2) dynamic analysis of pickup heads for DVDs, (3) ultrasonic
surface wave measurements,
and (4) rotating and optically rough surface measurements. It
is clear from the
experimental data obtained that this newly developed miniature
interferometer system
can satisfy the stringent demands of today''s ultra-high
performance machinery such
as optical/magnetic disk drives, compact disk drives, digital
video disk drives,
micro sensors/actuators, etc.
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