your "design around".
Interesting Patent Case
patentability protection against infringement?
This is the second issue of Directions, a newsletter from TechRoadmap Inc. discussing intellectual property issues and
ideas. We hope to stimulate you to examine and improve your own IP
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Patenting your "design around"
In today's competitive environment we are often faced with the problem
of "designing around" prior art. In the patent case discussed
below we see an excellent example of how designing around an existing
patented product works. In Zygo v. Wyco we also see the value in
patenting the design around. Although not a certainty by any means, the
patentablility of a design around is a good defense against infringement
Prior art comes in two forms,
protected and public. Public prior art is openly revealed information
such as the IBM Technical Disclosure Bulletin,
whose sole purpose was to put selected technical concepts into the
public domain (thereby ensuring IBM's freedom to use). Public prior art
bars us from protecting our product with a patent, but does not keep us
from incorporating those features in our product. More
difficult is protected prior art; that is, an existing unexpired patent.
Protected prior art not only keeps us from protecting that aspect of our product but
also may bar us from selling it at all. Often the only solution for
bringing a product to market is to develop a "design around".
around is best executed early in your design cycle. One of
TechRoadmap's Invention Mining activities is guiding your
engineers through the forest of prior art to help you avoid the costs of
late redesigns and to help deflect infringement suits. Working as a
team, your engineers, your patent attorney, and TechRoadmap can identify
design arounds that have a high likelihood of patentability. As Wyco learned by experience, not every alternative design escapes the
"doctrine of equivalents" and doing a redesign in the middle
of an infringement suit is less than pleasant, but a design that is
patented over the identified prior art will go a long way to protect you
in infringement suits.
high tech businesses the need to design around is prevalent. Start-ups
entering an established marketplace will surely design their products
similar to existing products and established competitors always eyeball
each other's products for significant improvements.
you cannot license the protected prior art, then you must design around.
To ease the pain, consider these steps:
the prior art - particularly patents - continually through your
product development cycle. There's no sense in re-inventing someone
else's wheel and you might as well know about it as early as
the openings for your design - TechRoadmap and your Patent
Attorney can help you understand what is actually claimed by the
prior art and what regions are left open for you.
a patent covering your design around as early as possible -
Again, while not a panacea, patentability is a part of your defense
against infringement...but only if the patent has issued by the time
you need it.
a patent examiner's concern that your design around is
"obvious" during the non-adversarial patent
prosecution process is likely to be easier and less expensive than
fighting the doctrine of equivalents in an adversarial infringement
in the preceding article should be construed as legal advice. TechRoadmap
Inc serves as an interface between companies and their legal counsel.
Is patentability protection against
v. WYKO Corp.
March 26, 1996
Corporation appealed the judgment of the US District
Court for the District of Arizona (Civil Action No. CIV 88-454-T-JLQ),
which held Zygo Corporation's US Patent 4,201,473
("the '473 patent") for an interferometer system not invalid
and was infringed by three models of Wyko interferometers. The appeals
court held that the district court clearly erred in finding that one
model, the Wyko 6000 Redesign, infringed under the doctrine of
equivalents but affirmed the finding of infringement on the original
Wyko 6000 designs. In this discussion I have only included a review of the
infringement issues, based on the published court opinion.
In 1977, Zygo introduced the Zygo Mark II,
based on the invention claimed in the '473 patent. The Mark II has an alignment
mode in which the reference and test wavefronts are collected by a series of optical elements and focused as two dots of
light onto a stationary diffuse screen. A visible cross-hair reticle is
embedded into the screen with intersection of the cross-hairs
pre-aligned to the optical axis. An internal TV camera is focused on the screen
so an image of the dots and
reticle is displayed on a CCTV monitor. An
operator moves each of the dots independently to the center of the alignment reticle at which
point alignment is achieved (viz., each beam parallel to the optical axis and thereby
parallel to each other) .
Five years later Wyko Corporation was founded.
In January 1988 the Wyco 6000, an interferometer intended to compete
with the Zygo instruments, was introduced. It appears that Wyco tried to
design around the '473 patent in the area of the alignment system. The Wyko 6000 included a stationary diffuse screen onto
which the reference and test wavefronts were focused as dots of light
which were, in turn, imaged onto a television camera, converted into electronic
data, and appeared on a computer monitor along with a cross-hair-like reticle that was generated by computer software.
During factory setup, the electronic cross-hair was aligned to the
system optical axis. An operator moved each dot until they overlapped at the center of the cross-hair,
which meant they were aligned.
The Wyko 6000
Redesign made its debut about one year after initiation of this lawsuit.
In the Redesign a further design around of the alignment system is
included. No reticle is displayed for alignment.
Instead, a prism is used which is factory-positioned so that its axis is
parallel to the optical axis of the interferometer. When so positioned,
the prism deflects light that is not parallel to its axis. If the
wavefronts are not in alignment, the prism creates a split-image of the
test and reference wavefronts such that four dots (two for each
wavefront) are projected onto the diffuse screen. This image is
transferred to a TV monitor. Both pairs of dots are moved together. When
properly aligned, the four dots coalesce into a single spot, which means
they are aligned along the optical axis of the interferometer.
Procedural History - The court entered its Findings of Fact and Conclusions of Law on
March 3, 1993, holding the '473 patent was neither invalid nor was the patent unenforceable
(two claims made by Wyco). While none of the accused Wyko devices were found to
literally infringe the '473 patent, the court concluded that all
versions of the accused Wyko devices infringed under the doctrine of
equivalents. In this appeal, Wyko alleged the district court erred in the finding that
the accused devices infringed the '473 patent under the doctrine of
INFRINGEMENT UNDER THE DOCTRINE OF EQUIVALENTS (or did
Wyco adequately design around the Zygo patent)
The infringement dispute in this case centers on the claim language
"means for collecting said two wavefronts and focusing them as
spots onto a diffuse screen containing an integral alignment reticle
having a marked center." The court construed the emphasized
language to mean the alignment reticle and the diffuse screen were
"one piece." Literal infringement is not an issue. No Wyko
device contains a unitary screen and an alignment reticle as required by
the claim. The only issue is infringement under the doctrine of
The appeals court stated that infringement under the doctrine of equivalents may be found where
those limitations of a claim not found exactly in the accused device are
met equivalently. Additionally, the court said it is well settled that each element of a claim is material and
essential, and that in order for a court to find infringement, the
plaintiff must show the presence of every element or its substantial
equivalent in the accused device. Infringement may not be found under the
doctrine of equivalents if a limitation is missing, that is, not
replaced with an equivalent substituent. But the substituent need not be in the exact
same location specified by the claim. If, in the context of the
invention, the substituent substantially performs the same function to
achieve the same result in the same way as the required limitation, that
limitation is satisfied.
Now, in the original Wyko 6000 devices, a reticle which coincided with the
location of the optical axis, in the words of the claim, an
"alignment reticle," was generated by hardware or software and
appeared on a monitor together with the two dots imaged by the camera
from the diffuse screen.
Thus, the image on the Wyko monitor duplicated the required image on the
monitor in the alignment mode of the Zygo invention. The court had no difficulty
agreeing that the image of the reticle generated on the monitor is the
equivalent of the physical reticle on the screen which is also imaged on
the monitor in the Zygo invention. While the alignment reticle has been
moved within the alignment leg of the accused interferometers, the
function of alignment is accomplished in the same way, by moving the two
spots to coalesce at the center of a reticle which coincides with the
optical axis of the interferometer. Similarly, the point at which the
crosshairs cross is at least equivalent to a marked spot.
court found that Wyco's first attempt to design around a Zygo feature
"failed" because the approach was equivalent to the patented
Turning to the Wyko 6000 Redesign, the court reached the opposite conclusion.
In these devices, an image inverting prism is placed in the path of the
wavefronts that emerge from the diffuse screen. Each portion of the
wavefronts that passes around the prism is projected as a spot on the
camera. Each part of the wavefront passing through the prism is
deflected and projected as a separate spot on the camera. The spots are
mirror images. When these four spots coincide, the positions of which
can be adjusted by the operator, alignment is achieved. In the Redesign,
there is no substitute "alignment reticle," that is,
crosshairs defining the optical axis of the interferometer. The
"alignment aid" is the prism structure which splits each of
the beams on its way to the camera into two so that four dots appear on
the monitor. These four dots are moved so as to coalesce into one, at
which point the beams are centered on the axis of the interferometer.
Thus, to find infringement, the prism structure must be found an
equivalent of an alignment reticle placed on the optical axis, a finding
which is not supportable. That both can be labeled "alignment
aids," as Zygo terms them, does not answer the question whether
they are equivalent within the concept of infringement. That the
substituent performs the same general function to achieve the same
result as the required element also does not establish their
equivalency. The result must be achieved in substantially the same way.
Thus, just incorporating the same general function, was not enough
to trigger infringement.
Finally, the court pointed out that for purposes of infringement under the doctrine of
equivalents, the differences between the claimed device and the accused
device must be insubstantial. According to Wyko, the fact that the Wyko 6000
Redesign alignment system was patented demonstrates the substantiality
of the differences between the claimed and accused devices. [emphasis
added] Wyko's patent, which cited the '473 patent as prior art, is thus presumed nonobvious in view of the '473 patent
until proven otherwise.
Thus, the court implied a logical imperative
that a patented device cannot be simultaneously non-obvious
(as determined by the USPTO) and insubstantial (required by the doctrine
As a footnote, remember that patent examinations
are not adversarial while infringement suits are. It should be easier to
make your non-obviousness case at the patent office than your
substantiality case in the court.
US Patent office
Searchable database of all US Patents and, now, published patent
The Patent Cafe - an on-line source of interesting insights into
current IP issues.
EKMS Inc. - a company with whom
we've worked that provides a range of IP management services including
portfolio analysis, deal-making, and process improvement.