Appeal No. 1998-0158 Page 2
Application No. 08/427,587
BACKGROUND
In a video cassette recorder (VCR), rotary heads are used
to record and reproduce audio and video signals. The heads
are bonded on small metal plates called head bases. In turn,
the head bases are attached to a drum. Precise positioning of
the heads on the drum is required.
Conventionally, the height of the rotary heads is set
using screws to elastically deform the head bases. When the
drum is subjected to mechanical vibrations or temperature
changes, however, the screws can loosen. Such loosening
changes the height of the heads, thereby increasing tracking
errors and crosstalk interference.
The invention at issue in this appeal sets the height of
a rotary head free from the influences of mechanical
vibrations and temperature changes. Specifically, a laser
beam heats a head base, causing it to deform plastically.
Such deformation bends the head base, thereby adjusting its
height.
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