Appeal No. 98-0174
Application 08/545,162
The invention is directed to a method and apparatus for
measuring small mass changes by quartz crystal microbalances. In
order to avoid the temperature dependency problem of the prior
art microbalance measurements, the invention senses mass changes
using a quartz crystal microbalance which automatically
compensates for variations in ambient temperatures without
affecting the accuracy of the microbalance. More particularly,
this is accomplished by forming a quartz crystal resonator
excitable in two different modes at the same time in such a
manner that the mass change and the temperature change can be
measured independently.
Independent method claim 1 is reproduced as follows:
1. A method of measuring small mass changes,
comprising the steps of;
utilizing a quartz crystal resonator onto which a
material of a certain mass is added, wherein the quartz crystal
can be excited along two modes simultaneously;
exciting the quartz crystal along the two modes
simultaneously;
measuring a change in a first resultant frequency
of said resonator;
measuring a change in a second resultant frequency
of said resonator; and
2
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