Ex parte Bird et al.

Board of Patent Appeals and Interferences

Sep 29, 1997

08096626 (B.P.A.I. Sep. 29, 1997)

1
THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered today (1) was not written
for publication in a law journal and (2) is not binding precedent of the
Board.
Paper No. 14
UNITED STATES PATENT AND TRADEMARK OFFICE
_____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_____________
Ex parte NEIL C. BIRD and
ALAN G. KNAPP
_____________
Appeal No. 96-1378
Application 08/096,6261
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ON BRIEF
_______________
Before MARTIN, BARRETT and LEE, Administrative Patent Judges.
MARTIN, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision in an appeal under 35 U.S.C. ' 134 from the
examiner's final rejection of claims 1-23, which are all of appellants'
pending claims, under 35 U.S.C. ' ' 103 and 103. We reverse.
The claimed invention relates to active matrix display devices having
display elements which are controlled by respective TFTs (TFT means Thin Film
Technology). In the prior art display devices described in appellants'
specification (at 1-2), digital video signals are converted to analog signals
which are applied to the column conductors via the TFTs, which operate as

1 Application for patent filed July 21, 1993.
Appeal No. 96-1378
Application 08/096,626
2
switches to transfer analog voltages to the display elements. In appellants
invention, the digital video signals are converted to pulse width signals that
control TFTs which are biased to operate as current sources, thereby causing
the display elements to be charged to voltage levels determined by the
duration of the respective pulse width signals.
Claim 1, which is representative, reads as follows:
1. A method of driving an active matrix display device having sets of
row and column conductors and an array of display elements each comprising
first and second electrodes with electro-optical material therebetween, the
first electrodes being connected to the drain of a respective TFT whose source
and gate are connected respectively to a column and a row conductor, in which
selection signals are applied to the row conductors and in which video
information signals are converted into corresponding time dependent signals,
characterised in that the time dependent signals are applied to the column
conductors and in that during the application of a selection signal to a row
of TFTs the TFTs are biased to act as current sources such that their
associated display elements are charged to a level dependent on the duration
of the applied time dependent signal.
The examiner relies on the following references:
Ohwada et al. (Ohwada) 4,750,813 Jun. 14, 1988
Young 5,095,304 Mar. 10, 1992
A. The ' 102(b) rejection
Claims 1-12 and 16-23 stand rejected under 35 U.S.C. ' 102(b) as
anticipated by Young. Since appellants have indicated (Brief at 7) that all
of these claims stand or fall together, we will consider only claim 1.
Young discloses a matrix display device whose construction permit s a
pair of rows of display elements 12 to share a single row conductor 14.
Referring to Figure 1, this as accomplished by using n-channel TFTs 11 and p-
channel TFTs 12 to control the display devices in the upper and lower rows,
respectively, of each pair, thereby permitting the upper row to be selected by
applying a positive pulse to the conductor and the lower row to be selected by
a negative pulse (Fig. 2). We do not agree with the examiner that Young
Appeal No. 96-1378
Application 08/096,626
3
anticipates the claim. Even assuming for the sake of argument that the video
voltages stored in analog shift register 22 and applied in parallel to the
column conductors can be considered to be "time dependent signals" (i.e., each
stored voltage took a different amount of time to reach its position in the
shift register), Young does not use the TFTs as current sources for charging
the display elements to levels dependent on the duration of the applied time
dependent signals, as required by the claim. Instead, the TFTs apply analog
voltages to the display elements for fixed time intervals which correspond to
the row selection time period TL (Fig. 2). Young explains that "each
switching transistor 11 of the addressed row is switched on for a time Tl
["TL" in Fig. 2] during which the video information signals are transferred
from the column conductors 15 to the display elements 12" (col. 5, lines 22-
26) and that "[t]he gating signals applied to Ri comprise a positive pulse
which turns on the row of n-channel TFTs enabling their associated picture
elements to be loaded with [the] video signal voltage[s] then present on the
column conductors 15" (col. 6, lines 31-36).
For the foregoing reason, the ' 102(b) rejection of claim 1 is reversed,
as is the ' 102(b) rejection of claims 2-12 and 16-23, which stand or fall
therewith.
B. The ' 103 rejection
Dependent claims 13-15 stand rejected under 35 U.S.C. ' 103 as being
unpatentable over Young considered with Ohwada. In view of appellants'
indication that these claims stand or fall together (Brief at 7), we will
consider only claim 13, which calls for resetting the TFTs to a predetermined
level prior to biasing them for current source operation. Ohwada does not
cure the above-noted deficiency in Young with respect to claim 1, on which
claim 13 depends through claim 2. As a result, the rejection of claims 13 is
Appeal No. 96-1378
Application 08/096,626
4
reversed, as is the rejection of claims 14 and 15, which stand or fall
therewith.
REVERSED
)
JOHN C. MARTIN )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
LEE E. BARRETT )
Administrative Patent Judge ) APPEALS AND
)
) INTERFERENCES
)
JAMESON LEE )
Administrative Patent Judge )
CORPORATE PATENT COUNSEL
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