Ex Parte TSAI

Board of Patent Appeals and Interferences

Feb 21, 2003

09121177 (B.P.A.I. Feb. 21, 2003)

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The opinion in support of the decision being entered
today was not written for publication in a law journal
and is not binding precedent of the Board.
Paper No. 22
UNITED STATES PATENT AND TRADEMARK OFFICE

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES

Ex parte JOHN C. TSAI

Appeal No. 2001-2088
Application No. 09/121,177

ON BRIEF

Before KRASS, BLANKENSHIP and SAADAT, Administrative Patent
Judges.
KRASS, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on appeal from the final rejection of
claims 1-6, 9 and 10. Claims 7, 8 and 11-16 have been indicated
by the examiner as being allowable and form no part of this
appeal.
The invention is directed to a servo track writing apparatus
Appeal No. 2001-2088
Application No. 09/121,177
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for accurately positioning a magnetic head mounted on a
positioning arm. The positioning arm is located within a disk
drive assembly and has a through hole. An external tracking arm
is moved in a fixed relationship with the positioning arm of the
disk drive assembly. The tracking arm has a detection system
mounted thereon for detecting the edges of the through hole in
the positioning arm, thereby maintaining it in a fixed positional
relationship with the positioning arm inside the disk drive
assembly.
Representative independent claim 1 is reproduced as follows:
1. A servo track writing apparatus for positioning a
read/write head in a disk drive assembly wherein the read/write
head is mounted on a positioning arm, the positioning arm has a
through hole therein, and the positioning arm is movable by a
positioning means over a media, the writing apparatus comprising:
a tracking arm located external to the disk drive assembly;
moving means for moving said tracking arm in fixed
relationship with the positioning arm;
position determining means for determining the position of
said tracking arm;
detection means for detecting the edges of the through hole
of the positioning arm relative to the tracking arm; and
a control unit suitable to:
operate said moving means and said detection means such that
said tracking arm and the positioning arm attain a particular
Appeal No. 2001-2088
Application No. 09/121,177
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geometric relationship;
operate said moving means and the positioning means such
that said tracking arm and the positioning arm synchronously are
maintained in said geometric relationship;
operate said position determining means to measure the
position of said tracking arm and therefrom infer the positions
of the positioning arm and the read/write head inside the disk
drive assembly; and
direct the disk drive assembly to position and maintain the
read/write head as desired for servo track writing in the media.
The examiner relies on the following reference:
Tsai 5,315,372 May 24, 1994
Claims 1-6, 9 and 10 stand rejected under 35 U.S.C. 103 as
unpatenable over Tsai.
Reference is made to the briefs and the answer for the
respective positions of appellant and the examiner.
OPINION
At the outset, we note that the prior art reference applied
against the instant claims is a patent issued to appellant. The
instant invention is said to be an improvement over that patent
Appeal No. 2001-2088
Application No. 09/121,177
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(the patent is discussed at pages 2-3 of the instant
specification), the improvement being the detection of the edges
of the through hole in the positioning arm. The specification
explains how such detection is used to provide non-invasive arm
position sensing which results in an efficient way to directly
and accurately determine the position of a very small positioning
arm and providing for adjustment of the position by producing
highly defined positional feedback.
Nevertheless, the examiner finds that the instant claimed
invention would have been obvious over the disclosure of Tsai,
referring to column 6, line 60 to column 7, line 29 of the
reference. The reference detects the edges of the reflected
laser beam and the examiner holds that it is an “alternative
equivalence...to detect the beam edges is merely a true
indication of the through hole edges, since the amount of light
beam incident on the photo detector going through the hole is
directly proportional to the amount of the light beam blocked by
the hole edges” [answer-page 3].
While the examiner’s rationale may have some credence if
there was some indication that the laser beam passing through the
hole does not diverge, i.e. the width of the beam passing through
the through hole is the width of the through hole if it does not
Appeal No. 2001-2088
Application No. 09/121,177
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spread out after passing through the through hole, we have no
such evidence that that is the case.
All of the rejected claims contain the limitation of
“detecting the edges of the through hole of the positioning arm”.
The applied reference simply does not refer to such a step,
detecting, instead, the edges of the reflected laser beam. The
examiner’s position is that detection of the edges of the
reflected laser beam is somehow equivalent to detecting the edges
of the through hole because of a direct proportion of the light
beam incident on the photodetectors to the amount of the light
beam blocked by the hole edges. Whatever “proportion” is being
referred to by the examiner, there is still no through hole edge
detection disclosed or suggested by Tsai. If the examiner is
contending that by measuring the edges of the beam width, this
somehow indicates the edges of the through hole, we disagree.
While this may be true for beam widths which do not vary after
exiting the through hole, in most cases, the beam may diverge
from the through hole. If this is the case, then measurement of
beam width by detecting the edges of the beam, does not indicate
the edges of the through hole since the beam width will vary with
distance from the through hole. Without knowing the distance
Appeal No. 2001-2088
Application No. 09/121,177
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from the through hole, width of the beam at any particular
distance from the through hole would indicate nothing about the
edges of the through hole.
Moreover, even if the edges of the through hole might be
able to be derived from measurements made by Tsai, this is no
indication as to why it would have been obvious to do so. It is
also no indication as to why it would have been obvious to then
apply the through hole edge detection, even if such detection
could be derived from Tsai, in such a manner as to cause the
positioning of a read/write head as desired for servo track
writing.
Accordingly, since the examiner has not convincingly shown
how Tsai is considered to detect the edges of the through hole of
the positioning arm and to employ such detection in positioning a
read/write head in a disk drive assembly, we will not sustain the
rejection of claims 1-6, 9 and 10 under 35 U.S.C. 103.
Appeal No. 2001-2088
Application No. 09/121,177
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The examiner’s decision is reversed.
REVERSED
ERROL A. KRASS )
Administrative Patent Judge )
)
)
)
)
HOWARD B. BLANKENSHIP ) BOARD OF PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
)
)
)
MAHSHID D. SAADAT )
Administrative Patent Judge )
Appeal No. 2001-2088
Application No. 09/121,177
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