Ex Parte Katayama

Board of Patent Appeals and Interferences

Feb 25, 2010

10437915 (B.P.A.I. Feb. 25, 2010)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte RYUICHI KATAYAMA
____________

Appeal 2009-009537
Application 10/437,915
Technology Center 2600
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Decided: February 25, 2010
____________

Before KENNETH W. HAIRSTON, JOHN A. JEFFERY
and MARC S. HOFF, Administrative Patent Judges.
HAIRSTON, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal under 35 U.S.C. §§ 6(b) and 134 from the final
rejection of claims 17 to 20. We will reverse.
The disclosed invention relates to an optical information reproducing
device used to detect radial tilt of a read-only type optical recording
medium. The light from a semiconductor laser is divided by a diffractive
optical element into three light beams, i.e., a main beam and two sub-beams,
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and the track error signals by the main beam and the two sub-beams are
detected by a differential phase detection method. The presence of the
diffractive optical element causes a difference in the light intensity
distributions of the main beam and the sub-beams that are incident on an
objective lens. If a radial tilt exists in the recording medium, then the phases
of the track error signals by the main beam and the sub-beams are shifted
with respect to each other (Figs. 1(A), 2(B); Spec. 1-7; Abstract).
Claim 17 is the only independent claim on appeal, and it reads as
follows:
17. An optical information reproducing device, comprising:
a light source for emitting light;
a diffractive optical element for dividing light emitted from the light
source into at least a main beam, a first sub-beam, and a second sub-beam;
an objective lens for focusing the main beam, the first sub-beam, and
the second sub-beam onto a same track of a read-only type optical recording
medium;
a photodetector for receiving light reflected by the read-only type
optical recording medium, the photodetector including a first light receiving
section for receiving the main beam in four divided portions, a second light
receiving section for receiving the first sub-beam in four divided portions,
and a third light receiving section for receiving the second sub-beam in four
divided portions;
circuitry for calculating a track error signal of the main beam using a
differential phase detection method based on outputs from the first light
receiving section, and for calculating a track error signal of the first and
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second sub-beams using the differential phase detection method based on
outputs from the second and third light receiving sections, and for
calculating a radial tilt signal based on the track error signal of the main
beam and the track error signal of the first and second sub-beams; and
correcting means for correcting a radial tilt of the optical recording
medium;
wherein the first light receiving section and the second and third light
receiving sections output signals for calculating track error signals by the
differential phase detection method;
wherein the diffractive optical element is for generating the main
beam and the first and second sub-beams with different light intensity
distributions when making incidence to the objective lens;
wherein the diffractive optical element outputs 0th-order light as the
main beam and ±1st-order diffracted lights as the first and second sub-beams;
wherein the circuitry is configured to calculate the track error signal
of the main beam by calculating a phase difference between a sum of two
outputs of the first light receiving section and a sum of two other outputs of
the first light receiving section; and
wherein the circuitry is configured to calculate the track error signal
of the first and second sub-beams by calculating a first phase difference
between a sum of two outputs of the second light receiving section and a
sum of two other outputs of the second light receiving section, and by
calculating a second phase difference between a sum of two outputs of the
third light receiving section and a sum of two other outputs of the third light
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receiving section, and by calculating a sum of the first phase difference and
the second phase difference.
The prior art relied upon by the Examiner in rejecting the claims on
appeal is:
Kuribayashi US 6,246,648 B1 Jun. 12, 2001
Sasaki US 7,095,693 B2 Aug. 22, 2006
(filed Mar. 8, 2002)
Katayama, Radial Tilt Detection Using 3-Beam Optical Head, Proceedings
of SPIE, Vol. 4090, 2000, pp. 309-318.
The Examiner rejected claims 17 to 19 under 35 U.S.C. § 103(a)
based upon the teachings of Katayama and Sasaki.
The Examiner rejected claim 20 under 35 U.S.C. § 103(a) based upon
the teachings of Katayama, Sasaki, and Kuribayashi.
Katayama describes a method for detecting radial tilt for a rewritable
optical disk using a three-beam optical head (Fig. 8; Abstract). The three
beams generated by a diffractive optical element are a main beam and two
sub-beams, and the focused spots for the three beams are placed on the same
track of the rewritable optical disk (Fig. 2; p. 310). A push-pull signal for
the main beam is used for tracking servo operation, and when radial tilt is 0
degrees, the push-pull signal for the sub-beam is zero if the push-pull for the
main beam is zero on the track. When the radial tilt is +0.5 degrees, the pus-
pull signal for the sub-beams becomes positive or negative if the radial tilt
for the main beam is zero on the track (p. 311). Thus, it is possible to
determine radial tilt based on the push-pull signals for the two sub-beams
(Fig. 6; pp. 311, 316, 317).
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The Examiner acknowledges that Katayama does not disclose the
following limitations in claim 17:
(a) that the optical recording medium is of the
read-only type; (b) that the photodetector includes
a first light receiving section for receiving the main
beam in four divided portions, a second light
receiving section for receiving the first sub-beam
in four divided portions, and a third light receiving
section for receiving the second sub-beam in four
divided portions; (c) calculating a track error
signal of the main beam using a differential phase
detection method, and calculating a track error
signal of the first and second sub-beams using the
differential phase detection method; (d) that the
circuitry is configured to calculate the track error
signal of the main beam by calculating a phase
difference between a sum of two outputs of the
first light receiving section and a sum of two other
outputs of the first light receiving section; and (e)
that the circuitry is configured to calculate the
track error signal of the first and second sub-beams
by calculating a first phase difference between a
sum of two outputs of the second light receiving
section and a sum of two other outputs of the
second light receiving section, and by calculating a
second phase difference between a sum of two
outputs of the third light receiving section and a
sum of two other outputs of the third light
receiving section, and by calculating a sum of the
first phase difference and the second phase
difference.
(Final Rej. 4, 5).
According to the Examiner (Final Rej. 5, 6), Sasaki describes all of the
limitations that are not taught by Katayama except for the ultimate
“calculating a sum” limitation in claim 17. The Examiner is of the opinion
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(Final Rej. 6) that such a calculation is the obvious result of the combined
teachings of the references “since Katayama et al. teach that ‘the push-pull
signals for the two sub-beams are added and used as the radial tilt signal’
(page 316, second to the last paragraph) and ‘sum signal for the sub-beams’
(page 317, second to the last paragraph).” The Examiner contends (Final
Rej. 6) that it would have been obvious to one of ordinary skill in the art to
use the read-only type optical medium taught by Sasaki in lieu of the
rewritable optical disk used by Katayama for the benefit of nondestructive,
permanent storage on the read-only disk. With respect to the other
limitations not described by Katayama, the Examiner is of the opinion (Final
Rej. 6, 7) that it would have been obvious to the skilled artisan to apply the
teachings of Sasaki to Katayama “to improve accuracy of tracking (this is a
well-known advantage of using differential phase detection method over the
conventional push-pull method), thereby enabling accurate reproduction of
data.”
Appellant argues inter alia that:
even if Katayama and Sasaki were combined, the
combination would not have an arrangement which
allows the tracking error of each of the main beam
and sub-beams to each be determined by DPD
[differential phase detection] at the same time,
because Sasaki teaches an arrangement where the
beams are arranged across two tracks to provide
for defect detection. The purpose of the Sasaki
arrangement where the receiving surface of the
main beam and the two sub beams are divided into
portions, whether these portions are two or four
divided portions, is mainly to allow for defect
detection (See col. 23, lines 13-33), and not to
allow for the tracking error of each of the main
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beam and sub beams to each be determined by
DPD at the same time.
(App. Br. 10).
In response to the Examiner’s statement (Ans. 9) that Sasaki “was
relied upon to show that the well-known DPD method could have been
applied in lieu of the push-pull method of Katayama et al. since both
techniques are art-recognized equivalents which have been used for the same
purpose of obtaining tracking errors,” Appellant argues (Reply Br. 3) that
“[o]ne skilled in the art, based on the Sasaki teachings, would have modified
Katayama only to provide an arrangement where the main beam and sub
beams would be arranged across two tracks in order to provide for defect
detection as stressed by Sasaki.”
Although the optical disk in Sasaki is of the read-only type (col. 1, ll.
10, 11), Figure 8 of this reference clearly shows that the main beam and the
two sub beams are across tracks as opposed to onto the same track as set
forth in the claims on appeal. The across the tracks arrangement of the main
and sub beams is for the purpose of detecting defects in the optical disk (col.
23, ll. 13-33), and not for detecting radial tilt of the optical disk as set forth
in the claims on appeal.
We agree with Appellant that Sasaki’s across the track teachings for a
read-only type optical disk are counter to Katayama’s on the same track
teachings for a rewritable optical disk. Other than the conclusion reached by
the Examiner, the record is completely silent as to an art-recognized
equivalency between the DPD method supposedly taught by Sasaki and the
push-pull method of Katayama.
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Thus, the obviousness rejection of claims 17 to 19 is reversed because
the Examiner’s proposed rejection fails to tie together the disparate
teachings of the applied references to support a legal conclusion of
obviousness. KSR Int’l Co. v. Teleflex, Inc., 550 U.S. 398, 418 (2007).
The obviousness rejection of claim 20 is reversed because the
teachings of Kuribayashi fail to cure the noted shortcomings in the combined
teachings of Katayama and Sasaki.
The decision of the Examiner is reversed.

REVERSED

KIS

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