Ex Parte Ikeda

Board of Patent Appeals and Interferences

Dec 22, 2008

09821636 (B.P.A.I. Dec. 22, 2008)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte HIROYUKI IKEDA
____________

Appeal 2008-5317
Application 09/821,636
Technology Center 2800
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Decided: December 22, 2008
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Before JOSEPH F. RUGGIERO, MAHSHID D. SAADAT,
and MARC S. HOFF, Administrative Patent Judges.

SAADAT, Administrative Patent Judge.

DECISION ON APPEAL
Appellant appeals under 35 U.S.C. § 134(a) from the Examiner’s
Final Rejection of claims 1-3 and 39-41, which are all of the claims pending
in this application as claims 4-38 have been canceled. We have jurisdiction
under 35 U.S.C. § 6(b).
We reverse.
Appeal 2008-5317
Application 09/821,636

STATEMENT OF THE CASE
Appellant’s invention relates to a thin film transistor display and a
method for controlling the threshold voltage of the thin film transistors
(Spec. 7-12).
Independent Claim 1 is representative and reads as follows:
1. A display apparatus comprising:

a plurality of thin film transistors, each of said thin film
transistor comprising a semiconductor thin film constituting a channel
and having a threshold voltage, and a first gate electrode on one side
of said semiconductor thin film and a second gate electrode on an
opposite side of said semiconductor thin film,

and further comprising a means for adjusting the threshold
voltage by applying a first threshold adjustment voltage to the second
gate electrode when the first gate electrode receives a first control
voltage and applying a second threshold adjustment voltage different
than the first threshold adjustment voltage to the second gate electrode
when the first electrode receives a second control voltage.

The Examiner relies on the following prior art in rejecting the claims:
Kubota US 5,808,595 Sep. 15, 1998

Claims 1-3 and 39-41 stand rejected under 35 U.S.C. § 102(b) as
being anticipated by or, in the alternative, under 35 U.S.C. § 103(a) as being
unpatentable over Kubota.1

1 The Examiner relies on “known facts” or “obvious” modifications to
Kubota in the 35 U.S.C. § 103 rejection of claims 2, 3, 40, and 41 only in the
Final Rejection (mailed Nov. 2, 2005), but does not explain what
modification to Kubota would render claims 1 and 39 obvious.
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Appeal 2008-5317
Application 09/821,636

Rather than repeat the arguments here, we make reference to the
Briefs and the Answer for the respective positions of Appellant and the
Examiner.

ISSUE
The issue is whether the Examiner erred in rejecting the claims under
35 U.S.C. §§ 102(b) and 103(a). The issue specifically turns on whether
Kubota anticipates Appellant’s claimed invention by disclosing
applying a first threshold adjustment voltage to the second gate
electrode when the first gate electrode receives a first control voltage
and applying a second threshold adjustment voltage different than the
first threshold adjustment voltage to the second gate electrode when
the first electrode receives a second control voltage,

as recited in claim 1.

FINDINGS OF FACT
1. Kubota relates to a thin film transistor having a thin-film
channel region which is formed between a conductive electrode and a gate
electrode. A constant voltage applied to the conductive electrode shifts the
threshold voltage of the channel. (Abstract).
2. As depicted in Figures 1(a) and 1(b) of Kubota, a constant
voltage is applied to the conductive electrode 14 placed beneath a
polysilicon thin-film layer 12 which acts as the active layer and forms the
channel region (col. 12, ll. 25-33).
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Appeal 2008-5317
Application 09/821,636

3. The gate electrode 16 is formed on the channel layer, on the
opposite side of the conductive layer 14, and separated by the gate insulating
layer 15 (col. 12, ll. 33-35).
4. Kubota shows a graph of gate-source voltage vs. drain-source
current characteristics in Figure 4 where two different values of no bias
voltage and -20 volts are applied to the conductive electrode. The graph
shows the threshold voltage shifted by 2.5 volts by application of the bias
voltage to the conductive electrode. (Col. 13, ll. 27-37).
5. Kubota discloses that different constant bias voltages are
applied to the conductive electrode for each type of transistors in the buffer
circuits 22 and the sampling circuits 23 of Figures 8 and 9 (col. 16, ll. 8-13
and 22-29).
PRINCIPLES OF LAW
A rejection for anticipation under section 102 requires that each and
every limitation of the claimed invention be disclosed in a single prior art
reference. See In re Paulsen, 30 F.3d 1475, 1478-79 (Fed. Cir. 1994).
“Anticipation of a patent claim requires a finding that the claim at issue
‘reads on’ a prior art reference.” Atlas Powder Co. v. IRECO, Inc., 190 F.3d
1342, 1346 (Fed. Cir. 1999) (quoting Titanium Metals Corp. of Am. v.
Banner, 778 F.2d 775, 781 (Fed. Cir. 1985)).
ANALYSIS
Appellant argues that Kubota applies a constant voltage to the
conductive electrode which does not change based upon the application of
one of two or more voltages to the gate electrode (App. Br. 9). Appellant
asserts that the graph in Figure 4 and the disclosure in column 12 are
consistent as to application of a constant voltage of 0 or -20 throughout the
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Application 09/821,636

entire range of control voltage applied to the gate or the first electrode (App.
Br. 10).
The Examiner argues that claims 1 and 39 do not require applying the
two different threshold adjustment voltages during circuit operation (Ans. 5).
The Examiner points to the two constant threshold voltages depicted in
Figure 4 of Kubota as the applied first and the second threshold adjustment
voltages showing a shift of 2.5 V, at the points corresponding to two gate
voltages of about 3 V and 6 V where the arrows touch the dashed line and
the solid line (Ans. 5-6). The Examiner further argues that the limitation of
for adjusting the threshold voltage by applying a first threshold
adjustment voltage to the second gate electrode when the first gate
electrode receives a first control voltage and applying a second
threshold adjustment voltage different than the first threshold
adjustment voltage to the second gate electrode when the first
electrode receives a second control voltage

does not limit the claim since such recitation is merely functional (Ans. 7-8).
We disagree with the Examiner’s characterization of the claimed
limitation as merely “functional languages” and “nonlimiting.” As argued
by Appellant (Reply Br. 5), claims 1 and 39 should be construed as
including means plus function languages which require a means for
adjusting the threshold voltage by
applying a first threshold adjustment voltage to the second gate
electrode when the first gate electrode receives a first control voltage
and applying a second threshold adjustment voltage different than the
first threshold adjustment voltage to the second gate electrode when
the first electrode receives a second control voltage.

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As such, the term “when” in claim 1 indicates a condition for applying the
first and the second threshold adjustment voltages in relation with the first
and second control voltages applied to the first electrode.
Therefore, we disagree with the Examiner that applying the two bias
voltages shown in Figure 4 of Kubota meets the above stated claimed
language. We specifically disagree with the Examiner’s reference (Ans. 5)
to the 3V and 6V values on the Vgs axis in Figure 4 as the first and the
second control voltage corresponding to the first and the second threshold
adjustment voltages applied to the conductive electrode since each of the
bias voltage values is applied to the conductive electrode for the entire range
of Vgs values. Kubota applies a constant voltage to the conductive electrode
14, positioned across from the gate electrode and on the opposite side of the
channel layer, for adjusting the threshold voltage of the thin-film transistor
(FF 1-3). The threshold voltage shift of 2.5 V in Figure 4 of Kubota is a
measure of a general shift in threshold voltage when no bias is compared
with a -20 V bias applied to the conductive electrode 14, each to the entire
range of Vgs values (FF 4). In other words, in either case of the applied bias
voltage, Kubota discloses no change in the threshold adjustment voltage that
corresponds to a first or second control voltage applied to the gate electrode
16. The different bias voltages indicated in Kubota are in fact applied to
different transistors in the buffer circuit and the sampling circuit according
to their required threshold adjustment (FF 5).
CONCLUSION
On the record before us, we find that Appellant has shown error in the
Examiner’s position that Kubota anticipates claim 1 or other independent
claim 39 which includes similar limitations. Therefore, in view of our
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Application 09/821,636

analysis above, the 35 U.S.C. § 102 rejection of claims 1-3 and 39-41 as
anticipated by Kubota cannot be sustained. Additionally, we do not sustain
the 35 U.S.C. § 103 rejection of these claims over Kubota since the
Examiner has not identified any modifications to Kubota to overcome the
deficiencies discussed above.

DECISION
The decision of the Examiner rejecting claims 1-3 and 39-41 is reversed.

REVERSED

gvw

ROBERT J. DEPKE
ROCKEY, DEPKE & LYONS, LLC
SEARS TOWER
SUITE 5450
CHICAGO, IL 60606-6306
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