958 F.2d 1053
60 U.S.L.W. 2603, 22 U.S.P.Q.2d 1033
(Cite as: 958 F.2d 1053)
ARRHYTHMIA RESEARCH TECHNOLOGY, INC., Plaintiff-Appellant,
v.
CORAZONIX CORPORATION, Defendant-Appellee.
No. 91-1091.
United States Court of Appeals,
Federal Circuit.
March 12, 1992.
Rehearing Denied May 5, 1992.
Holder of patent directed to analysis of electrocardiographic
signals in order to determine certain characteristics of heart
function brought infringement suit. The United States District Court
for the Northern District of Texas, A. Joe Fish, and John B. Tolle,
JJ., declared patent invalid for failure to claim statutory subject
matter, and plaintiff appealed. The Court of Appeals, Pauline Newman,
Circuit Judge, held that process and apparatus claims satisfied
criteria for statutory subject matter.
Reversed and remanded.
Rader, Circuit Judge, filed concurring opinion.
*1054 John F. Flannery, Fitch, Even, Tabin & Flannery, Chicago,
Ill., argued for plaintiff-appellant. With him on the brief was
Robert J. Fox.
Robert W. Turner, Jones, Day, Reavis & Pogue, Dallas, Tex.,
argued for defendant-appellee. With him on the brief was John E.
Vick, Jr., Hubbard, Thurman, Tucker & Harris, Dallas, Tex.
Before NEWMAN, LOURIE and RADER, Circuit Judges.
PAULINE NEWMAN, Circuit Judge.
Arrhythmia Research Technology, Inc. appeals the grant of
summary judgment by the United States District Court for the Northern
District of Texas [FN1] declaring United States Patent No. 4,422,459
to Michael B. Simson (the '459 or Simson patent) invalid for failure
to claim statutory subject matter under 35 U.S.C. s 101. The court
did not decide the question of infringement.
FN1. Arrhythmia Research Technology, Inc. v. Corazonix Corp.,
No. CA 3-88- 1745-AJ (N.D.Tex. October 3, 1990), reconsid. denied
(November 8, 1990) (Order); appeal authorized (November 9, 1990)
(Order).
We conclude that the claimed subject matter is statutory in
terms of section 101. The judgment of invalidity on this ground is
reversed.
The Simson Invention
The invention claimed in the '459 patent is directed to the
analysis of electrocardiographic signals in order to determine certain
characteristics of the heart function. In the hours immediately after
a heart attack (myocardial infarction) the victim is particularly
vulnerable to an acute type of heart arrhythmia known as ventricular
tachycardia. Ventricular tachycardia leads quickly to ventricular
fibrillation, in which the heart ceases effectively to pump blood
through the body. Arrhythmia Research states that 15-25% of heart
attack victims are at high risk for ventricular tachycardia. It can
be treated or prevented with certain drugs, but these drugs have
undesirable and sometimes dangerous side effects. Dr. Simson, a
cardiologist, sought a solution to the problem of determining which
heart attack victims are at high risk for ventricular tachycardia, so
that these persons can be carefully monitored and appropriately
treated.
Heart activity is monitored by means of an electrocardiograph
device, whereby electrodes attached to the patient's body detect the
heart's electrical signals in accordance with the various phases of
heart activity. The signals can be displayed in wave form on a
monitor and/or recorded on a chart. It was known that in patients
subject to ventricular tachycardia certain anomalous waves having very
low amplitude and high frequency, known as "late potentials," appear
toward the end of the QRS [FN2] segment of the electrocardiographic
signal, that is, late in the ventricular contraction cycle. Dr.
Simson's method of detecting and measuring these late potentials in
the QRS complex, and associated apparatus, are the subject of the '459
patent.
FN2. According to Arrhythmia Research, the QRS complex lasts
about one tenth of a second and arises from the depolarization of the
ventricles prior to contraction.
*1055 The '459 patent specification describes these procedures.
Certain of the heart attack patient's electrocardiographic signals,
those obtained from electrodes designated as X, Y, and Z leads, are
converted from analog to digital values, and a composite digital
representation of the QRS segment is obtained by selecting and
averaging a large number of the patient's QRS waveforms. The anterior
portion of the composite QRS waveform is first isolated, and then
processed by a digital high pass filter in reverse time order; that
is, backwards. This step of reverse time order filtering is described
as the critical feature of the Simson invention, in that it enables
detection of the late potentials by eliminating certain perturbations
that obscure these signals. The root mean square of the reverse time
filtered output is then calculated, as described in the specification,
to determine the average magnitude of the anterior portion of the QRS
complex. Comparison of the output, which is measured in microvolts,
with a predetermined level of high frequency energy, indicates whether
the patient is subject to ventricular tachycardia. That is, if the
root mean square magnitude is less than the predetermined level, then
low amplitude, high frequency late potentials have been shown to be
present, indicating a higher risk of ventricular tachycardia. If the
root mean square value is greater than the predetermined level, high
risk for ventricular tachycardia is not indicated.
Certain steps of the invention are described as conducted with
the aid of a digital computer, and the patent specification sets forth
the mathematical formulae that are used to configure (program) the
computer. The specification states that dedicated, specific purpose
equipment or hard wired logic circuitry can also be used.
The district court held that the method and apparatus claims of
the Simson patent are directed to a mathematical algorithm, and thus
do not define statutory subject matter. Claim 1 is the broadest
method claim: 1. A method for analyzing electrocardiograph signals to
determine the presence or absence of a predetermined level of high
frequency energy in the late QRS signal, comprising the steps of:
converting a series of QRS signals to time segments, each segment
having a digital value equivalent to the analog value of said signals
at said time; applying a portion of said time segments in reverse time
order to high pass filter means; determining an arithmetic value of
the amplitude of the output of said filter; and comparing said value
with said predetermined level. Claim 7 is a representative apparatus
claim: 7. Apparatus for analyzing electrocardiograph signals to
determine the level of high frequency energy in the late QRS signal
comprising: means for converting X, Y, and Z lead electrocardiographic
input signals to digital valued time segments; means for examining
said X, Y, and Z digital valued time segments and selecting therefrom
the QRS waveform portions thereof; means for signal averaging a
multiplicity of said selected QRS waveforms for each of said X, Y, and
Z inputs and providing composite, digital X, Y, and Z QRS waveforms;
high pass filter means; means for applying to said filter means, in
reverse time order, the anterior portion of each said digital X, Y,
and Z waveform; and means for comparing the output of said filter
means with a predetermined level to obtain an indication of the
presence of a high frequency, low level, energy component in the
filter output of said anterior portions. The Patent and Trademark
Office had granted the patent without questioning that its claims were
directed to statutory subject matter under s 101.
35 U.S.C. s 101
Whether a claim is directed to statutory subject matter is a
question of law. Although *1056 determination of this question may
require findings of underlying facts specific to the particular
subject matter and its mode of claiming, in this case there were no
disputed facts material to the issue. Thus we give plenary review to
the question, with appropriate recognition of the burdens on the
challenger of a duly issued United States patent. See 35 U.S.C. s
282 (duly issued patent is presumed valid); Interconnect Planning
Corp. v. Feil, 774 F.2d 1132, 1139, 227 USPQ 543, 548, (Fed.Cir.1985)
(statutory presumption of validity is based in part on recognition of
the expertise of patent examiners).
[1] A new and useful process or apparatus is patentable subject
matter, as defined in 35 U.S.C. s 101: Whoever invents or discovers
any new and useful process, machine, manufacture, or composition of
matter, or any new and useful improvement thereof, may obtain a patent
therefor, subject to the conditions and requirements of this title.
The Supreme Court has observed that Congress intended section 101 to
include "anything under the sun that is made by man." Diamond v.
Chakrabarty, 447 U.S. 303, 309, 100 S.Ct. 2204, 2208, 65 L.Ed.2d 144,
206 USPQ 193, 197 (1980), quoting S.Rep. No. 1979, 82d Cong., 2d
Sess., 5 (1952); H.R.Rep. No. 1923, 82d Cong., 2d Sess., 6 (1952).
There are, however, qualifications to the apparent sweep of this
statement. Excluded from patentability is subject matter in the
categories of "laws of nature, physical phenomena, and abstract
ideas". Diamond v. Diehr, 450 U.S. 175, 185, 101 S.Ct. 1048, 1056,
67 L.Ed.2d 155, 209 USPQ 1, 7 (1981). A mathematical formula may
describe a law of nature, a scientific truth, or an abstract idea. As
courts have recognized, mathematics may also be used to describe steps
of a statutory method or elements of a statutory apparatus. The
exceptions to patentable subject matter derive from a lengthy
jurisprudence, but their meaning was probed anew with the advent of
computer-related inventions.
In Gottschalk v. Benson, 409 U.S. 63, 72, 93 S.Ct. 253, 257, 34
L.Ed.2d 273, 175 USPQ 673, 676 (1972) the Court held that a patent
claim that "wholly pre-empts" a mathematical formula used in a general
purpose digital computer is directed solely to a mathematical
algorithm, [FN3] and therefore does not define statutory subject
matter under section 101. The Court described the mathematical
process claimed in Benson as "so abstract and sweeping as to cover
both known and unknown uses of the BCD [binary coded decimal] to pure
binary conversion", 409 U.S. at 68, 93 S.Ct. at 255, 175 USPQ at 675,
citing O'Reilly v. Morse, 56 U.S. (15 How.) 62, 113, 14 L.Ed. 601
(1852) for its holding that the patentee may not claim more than he
has actually invented.
FN3. A mathematical algorithm was defined in Benson as a
procedure or formula for solving a particular mathematical problem.
409 U.S. at 65, 93 S.Ct. at 254, 175 USPQ at 674. As discussed in In
re Iwahashi, 888 F.2d 1370, 1374, 12 USPQ2d 1908, 1911 (Fed.Cir.1989),
however, any step-by-step process, whether mechanical, electrical,
biological or chemical, involves an "algorithm" in the broader sense
of the term.
In Parker v. Flook, 437 U.S. 584, 591, 98 S.Ct. 2522, 2526, 57
L.Ed.2d 451, 198 USPQ 193, 198 (1978) the Court explained that the
criterion for patentability of a claim that requires the use of
mathematical procedures is not simply whether the claim "wholly
pre-empts" a mathematical algorithm, but whether the claim is directed
to a new and useful process, independent of whether the mathematical
algorithm required for its performance is novel. Applying these
criteria the Court held nonstatutory a method claim for
computer-calculating "alarm limits" for use in a catalytic conversion
process, on the basis that "once that algorithm is assumed to be
within the prior art, the application, considered as a whole, contains
no patentable invention." Flook, 437 U.S. at 594, 98 S.Ct. at 2527,
198 USPQ at 199.
In accordance with Flook, the claims were analyzed to determine
whether the process itself was new and useful, assuming the
mathematical algorithm was "well known". Id. at 592, 98 S.Ct. at
2527, 198 USPQ at 198. As the jurisprudence developed, *1057
inventions that were implemented by the mathematically-directed
performance of computers were viewed in the context of the practical
application to which the computer-generated data were put. The Court
of Customs and Patent Appeals observed in In re Bradley, 600 F.2d 807,
811-112, 202 USPQ 480, 485 (CCPA 1979), aff'd by an equally divided
court, sub nom. Diamond v. Bradley, 450 U.S. 381, 101 S.Ct. 1495, 67
L.Ed.2d 311 (1981): It is of course true that a modern digital
computer manipulates data, usually in binary form, by performing
mathematical operations, such as addition, subtraction,
multiplication, division, or bit shifting, on the data. But this is
only how the computer does what it does. Of importance is the
significance of the data and their manipulation in the real world,
i.e., what the computer is doing. [Emphases in original] Thus
computers came to be generally recognized as devices capable of
performing or implementing process steps, or serving as components of
an apparatus, without negating patentability of the process or the
apparatus. In Diamond v. Diehr the Court explained that non-statutory
status under section 101 derives from the "abstract", rather than the
"sweeping", nature of a claim that contains a mathematical algorithm.
The Court stated: "While a scientific truth, or the mathematical
expression of it, is not a patentable invention, a novel and useful
structure created with the aid of knowledge of scientific truth may
be." Diehr, 450 U.S. at 188, 101 S.Ct. at 1057, 209 USPQ at 8-9,
quoting Mackay Radio & Telegraph Co. v. Radio Corp. of America, 306
U.S. 86, 94, 59 S.Ct. 427, 431, 83 L.Ed. 506, 40 USPQ 199, 202 (1939).
The mathematical algorithm in Diehr was the known Arrhenius equation,
and the Court held that when the algorithm was incorporated in a
useful process, the subject matter was statutory. The Court confirmed
the rule that process steps or apparatus functions that entail
computer-performed calculations, whether the calculations are
described in mathematical symbols or in words, do not of themselves
render a claim nonstatutory. Diehr, 450 U.S. at 187, 101 S.Ct. at
1057, 209 USPQ at 8. The Court clarified its earlier holdings, [FN4]
stating that "[i]t is inappropriate to dissect the claims into old and
new elements and then to ignore the presence of the old elements in
the [section 101] analysis." Id. at 188, 101 S.Ct. at 1058, 209 USPQ
at 9.
FN4. Although commentators have differed in their
interpretations of Benson, Flook, and Diehr, it appears to be
generally agreed that these decisions represent evolving views of the
Court, and that the reasoning in Diehr not only elaborated on, but in
part superseded, that of Benson and Flook. See, e.g., R.L. Gable &
J.B. Leaheey, The Strength of Patent Protection for Computer Products,
17 Rutgers Computer & Tech.L.J. 87 (1991); D. Chisum, The
Patentability of Algorithms, 47 U.Pitt.L.Rev. 959 (1986).
[2] The Court thus placed the patentability of computer-aided
inventions in the mainstream of the law. The ensuing mode of analysis
of such inventions was summarized in In re Meyer, 688 F.2d 789, 795,
215 USPQ 193, 198 (CCPA 1982): In considering a claim for compliance
with 35 USC 101, it must be determined whether a scientific principle,
law of nature, idea, or mental process, which may be represented by a
mathematical algorithm, is included in the subject matter of the
claim. If it is, it must then be determined whether such principle,
law, idea, or mental process is applied in an invention of a type set
forth in 35 USC 101. The law crystallized about the principle that
claims directed solely to an abstract mathematical formula or
equation, including the mathematical expression of scientific truth or
a law of nature, whether directly or indirectly stated, are
nonstatutory under section 101; whereas claims to a specific process
or apparatus that is implemented in accordance with a mathematical
algorithm will generally satisfy section 101.
In applying this principle to an invention whose process steps
or apparatus elements are described at least in part in terms of
mathematical procedures, the mathematical procedures are considered in
the context of the claimed invention as a whole. Diehr, *1058 450
U.S. at 188, 101 S.Ct. at 1057, 209 USPQ at 9. Determination of
statutory subject matter has been conveniently conducted in two
stages, following a protocol initiated by the Court of Customs and
Patent Appeals in In re Freeman, 573 F.2d 1237, 197 USPQ 464 (CCPA
1978); modified after the Court's Flook decision by In re Walter, 618
F.2d 758, 205 USPQ 397 (CCPA 1980); and again after the Court's Diehr
decision by In re Abele, 684 F.2d 902, 214 USPQ 682 (CCPA 1982).
[3] This analysis has been designated the Freeman-Walter-Abele
test for statutory subject matter. It is first determined whether a
mathematical algorithm is recited directly or indirectly in the claim.
If so, it is next determined whether the claimed invention as a whole
is no more than the algorithm itself; that is, whether the claim is
directed to a mathematical algorithm that is not applied to or limited
by physical elements or process steps. Such claims are nonstatutory.
However, when the mathematical algorithm is applied in one or more
steps of an otherwise statutory process claim, or one or more elements
of an otherwise statutory apparatus claim, the requirements of section
101 are met. The court explained in Abele, 684 F.2d at 907, 214 USPQ
at 686: [P]atentable subject matter [is not limited] to claims in
which structural relationships or process steps are defined, limited
or refined by the application of the algorithm. Rather, Walter should
be read as requiring no more than that the algorithm be "applied in
any manner to physical elements or process steps," provided that its
application is circumscribed by more than a field of use limitation or
non- essential post-solution activity. As summarized by the PTO in Ex
Parte Logan, 20 USPQ2d 1465, 1468 (PTO Bd.Pat.App. and Interf.1991),
the emphasis is "on what the claimed method steps do rather than how
the steps are performed". (Emphases in original)
Although the Freeman-Walter-Abele analysis is not the only test
for statutory subject matter, Meyer, 688 F.2d at 796, 215 USPQ at 198,
and this court has stated that failure to meet that test may not
always defeat the claim, In re Grams, 888 F.2d 835, 839, 12 USPQ2d
1824, 1827 (Fed.Cir.1989), this analytic procedure is conveniently
applied to the Simson invention.
Analysis
Arrhythmia Research states that the district court erred in law,
and that the combination of physical, mechanical, and electrical steps
that are described and claimed in the '459 patent constitutes
statutory subject matter. Arrhythmia Research stresses that the claims
are directed to a process and apparatus for detecting and analyzing a
specific heart activity signal, and do not preempt the mathematical
algorithms used in any of the procedures. Arrhythmia Research states
that the patentability of such claims is now well established by law,
precedent, and practice.
Corazonix states that the claims define no more than a
mathematical algorithm that calculates a number. Corazonix states
that in Simson's process and apparatus claims mathematical algorithms
are merely presented and solved, and that Simson's designation of a
field of use and post-solution activity are not essential to the
claims and thus do not cure this defect. Thus, Corazonix states that
the claims are not directed to statutory subject matter, and that the
district court's judgment was correct.
A. The Process Claims
Although mathematical calculations are involved in carrying out
the claimed process, Arrhythmia Research argues that the claims are
directed to a method of detection of a certain heart condition by a
novel method of analyzing a portion of the electrocardiographically
measured heart cycle. This is accomplished by procedures conducted by
means of electronic equipment programmed to perform mathematical
computation.
Applying the Freeman-Walter-Abele protocol, we accept for the
purposes of this analysis the proposition that a mathematical *1059
algorithm is included in the subject matter of the process claims in
that some claimed steps are described in the specification by
mathematical formulae. See In re Johnson, 589 F.2d 1070, 1078, 200
USPQ 199, 208 (CCPA 1979) ("Reference to the specification must be
made to determine whether [claimed] terms indirectly recite
mathematical calculations, formulae, or equations.") We thus proceed
to the second stage of the analysis, to determine whether the claimed
process is otherwise statutory; that is, we determine what the claimed
steps do, independent of how they are implemented.
Simson's process is claimed as a "method for analyzing
electrocardiograph signals to determine the presence or absence of a
predetermined level of high- frequency energy in the late QRS signal".
This claim limitation is not ignored in determining whether the
subject matter as a whole is statutory, for all of the claim steps are
in implementation of this method. The electrocardiograph signals are
first transformed from analog form, in which they are obtained, to the
corresponding digital signal. These input signals are not
abstractions; they are related to the patient's heart function. The
anterior portion of the QRS signal is then processed, as the next
step, by the procedure known as reverse time order filtration. The
digital filter design selected by Dr. Simson for this purpose, known
as the Butterworth filter, is one of several known procedures for
frequency filtering of digital waveforms. The filtered signal is
further analyzed to determine its average magnitude, as described in
the specification, by the root mean square technique. Comparison of
the resulting output to a predetermined level determines whether late
potentials reside in the anterior portion of the QRS segment, thus
indicating whether the patient is at high risk for ventricular
tachycardia. The resultant output is not an abstract number, but is a
signal related to the patient's heart activity.
These claimed steps of "converting", "applying", "determining",
and "comparing" are physical process steps that transform one
physical, electrical signal into another. The view that "there is
nothing necessarily physical about 'signals' " is incorrect. In re
Taner, 681 F.2d 787, 790, 214 USPQ 678, 681 (CCPA 1982) (holding
statutory claims to a method of seismic exploration including the
mathematically described steps of "summing" and "simulating from").
The Freeman-Walter-Abele standard is met, for the steps of Simson's
claimed method comprise an otherwise statutory process whose
mathematical procedures are applied to physical process steps.
It was undisputed that the individual mathematical procedures
that describe these steps are all known in the abstract. The method
claims do not wholly preempt these procedures, but limit their
application to the defined process steps. In answering the question
"What did the applicant invent?", Grams, 888 F.2d at 839, 12 USPQ2d at
1827, the Simson method is properly viewed as a method of analyzing
electrocardiograph signals in order to determine a specified heart
activity. Like the court in Abele, which was "faced simply with an
improved CAT-scan process", 684 F.2d at 909, 214 USPQ at 688, the
Simson invention is properly viewed as an electrocardiograph analysis
process. The claims do not encompass subject matter transcending what
Dr. Simson invented, as in O'Reilly v. Morse, 56 U.S. (15 How.) at 113
(claims covered any use of electric current to transmit characters at
a distance); or in Benson, 409 U.S. at 68, 93 S.Ct. at 255, 175 USPQ
at 675 (use of claimed process could "vary from the operation of a
train to verification of driver's licenses to researching the law
books for precedents"); or in Grams, 888 F.2d at 840, 12 USPQ2d at
1828 (invention had application to "any complex system, whether it be
electrical, mechanical, chemical or biological, or combinations
thereof.")
The Simson claims are analogous to those upheld in Diehr,
wherein the Court remarked that the applicants "do not seek to patent
a mathematical formula.... they seek only to foreclose from others
the use of that equation in conjunction with all of the other steps in
their claimed process". 450 U.S. at 187, 101 S.Ct. at 1057, 209 *1060
USPQ at 8. Simson's claimed method is similarly limited. The process
claims comprise statutory subject matter.
B. The Apparatus Claims
The Simson apparatus for analyzing electrocardiographic signals
is claimed in the style of 35 U.S.C. s 112, paragraph 6, whereby
functionally described claim elements are "construed to cover the
corresponding structure, material, or acts described in the
specification and equivalents thereof". Thus the statutory nature vel
non of Simson's apparatus claims is determined with reference to the
description in the '459 patent specification. In re Iwahashi, 888
F.2d 1370, 1375, 12 USPQ2d 1908, 1911-12 (Fed.Cir.1989).
The apparatus claims require a means for converting the
electrocardiograph signals from the analog form in which they are
generated into digital form. This means is described in the
specification as a specific electronic device, a conventional
analog-to-digital converter. A minicomputer, configured as described
in the specification, is the means of calculating composite digital
time segments of the QRS waveform. The product is stored, as stated
in the specification, in the form of electrical signals. The high
pass filter means is described in the specification as the
minicomputer configured to perform the function of reverse time order
filtration of the anterior portion of the QRS waveform. The
specification and drawings show a disc memory unit to store the
composite QRS signals, and associated connecting leads to the
computer's processing unit. The comparing means is the processing
unit configured to perform the specified function of root mean square
averaging of the anterior portion of the QRS complex, and comparison
of the resulting output with a predetermined level to provide an
indication of the presence of late potentials in the
electrocardiograph signal.
The Simson apparatus claims thus define "a combination of
interrelated means" for performing specified functions. Iwahashi, 888
F.2d at 1375, 12 USPQ2d at 1911. The computer-performed operations
transform a particular input signal to a different output signal, in
accordance with the internal structure of the computer as configured
by electronic instructions. "The claimed invention ... converts one
physical thing into another physical thing just as any other
electrical circuitry would do". In re Sherwood, 613 F.2d 809, 819,
204 USPQ 537, 546 (CCPA 1980), cert. denied, 450 U.S. 994, 101 S.Ct.
1694, 68 L.Ed.2d 193 (1981) (holding statutory claims to an apparatus
for analyzing seismic signals including mathematically described means
for "sonogramming", "dividing", and "plotting").
[4] The use of mathematical formulae or relationships to
describe the electronic structure and operation of an apparatus does
not make it nonstatutory. Iwahashi, 888 F.2d at 1375, 12 USPQ2d at
1911. When mathematical formulae are the standard way of expressing
certain functions or apparatus, it is appropriate that mathematical
terms be used. See W.L. Gore & Assoc., Inc. v. Garlock, Inc., 721
F.2d 1540, 1556, 220 USPQ 303, 315 (Fed.Cir.1983), cert. denied, 469
U.S. 851, 105 S.Ct. 172, 83 L.Ed.2d 107 (1984) (patents are directed
to those of skill in the art). See also In re Bernhart, 417 F.2d
1395, 1399, 163 USPQ 611, 616 (CCPA 1969) ("all machines function
according to the laws of physics which can be mathematically set forth
if known.") That Simson's claimed functions could not have been
performed effectively without the speed and capability of electronic
devices and components does not determine whether the claims are
statutory.
Corazonix argues that the final output of the claimed apparatus
(and process) is simply a number, and that Benson and Flook support
the position that when the end product is a number, the claim is
nonstatutory and can not be saved by claim limitations of the use to
which this number is put. However, the number obtained is not a
mathematical abstraction; it is a measure in microvolts of a specified
heart activity, an indicator of the risk of ventricular tachycardia.
That the product is numerical is not a criterion of whether the claim
is directed to statutory subject matter. See Meyer, 688 F.2d at 796
n. 4, 215 USPQ at *1061 198 n. 4 (explaining that so-called "negative
rules" of patentability "were not intended to be separate tests for
determining whether a claim positively recites statutory subject
matter.")
[5] The Simson apparatus claims satisfy the criteria for
statutory subject matter. They are directed to a specific apparatus
of practical utility and specified application, and meet the
requirements of 35 U.S.C. s 101.
Conclusion
The judgment of invalidity on the ground that the claimed method
and apparatus do not define statutory subject matter is reversed. The
cause is remanded for resolution of remaining issues.
Taxable costs in favor of Arrhythmia Research.
REVERSED AND REMANDED.
RADER, Circuit Judge, concurring.
Nearly twenty years ago, in Gottschalk v. Benson, 409 U.S. 63,
93 S.Ct. 253, 34 L.Ed.2d 273 (1972), the Supreme Court dealt with a
computer process for conversion of binary coded decimals into pure
binary numbers. Benson held this mathematical algorithm ineligible
for patent protection. 409 U.S. at 65, 71-72, 93 S.Ct. at 254, 257.
Because computer programs rely heavily on mathematical algorithms,
commentators saw dire implications in the Supreme Court's opinion for
patent protection of computer software. For instance, one treatise,
citing Benson, stated: [A] recent Supreme Court decision seemingly
eliminated patent protection for computer software. Donald S. Chisum,
Patents s 1.01 (1991); see also id. at s 1.03[6].
The court upholds the '459 patent by applying a permutation of
the Benson algorithm rule. In reaching this result, the court adds
another cord to the twisted knot of precedent encircling and confining
the Benson rule. While fully concurring in the court's result and
commending its ability to trace legal strands through the tangle of
post-Benson caselaw, I read later Supreme Court opinions to have cut
the Gordian knot. The Supreme Court cut the knot by strictly limiting
Benson.
Relying on the language of the patent statute, the Supreme Court
in Diamond v. Diehr, 450 U.S. 175, 101 S.Ct. 1048, 67 L.Ed.2d 155
(1981), turned away from the Benson algorithm rule. Thus, I too
conclude that the '459 patent claims patentable subject matter--not on
the basis of a two-step post-Benson test, but on the basis of the
patentable subject matter standards in title 35. Rather than
perpetuate a nonstatutory standard, I would find that the subject
matter of the '459 patent satisfies the statutory standards of the
Patent Act.
I.
The questions presented by this case are whether the '459 patent
claims a process and apparatus within the meaning of 35 U.S.C. s 101
(1988). Section 101 states: Whoever invents or discovers any new and
useful process, machine, manufacture, or composition of matter, or any
new and useful improvement thereof, may obtain a patent therefor,
subject to the conditions and requirements of this title. According to
this language, "any" invention or discovery within the four broad
categories of "process, machine, manufacture, or composition of
matter" is eligible for patent protection. "Any" is an expansive
modifier which broadens the sweep of the categories. See Diamond v.
Chakrabarty, 447 U.S. 303, 308- 09, 100 S.Ct. 2204, 2207, 65 L.Ed.2d
144 (1980). The language of section 101 conveys no implication that
the Act extends patent protection to some subcategories of machines or
processes and not to others.
The limits on patentable subject matter within section 101 focus
not on subcategories of machines or processes, but on characteristics,
such as newness and usefulness. Section 101 also specifies that, in
addition to newness and usefulness, an invention or discovery must
satisfy other "conditions and requirements." These other "conditions
and requirements" encompass *1062 characteristics like nonobviousness
under 35 U.S.C. s 103 (1988), or requirements like those in 35 U.S.C.
s 112 (1988). In other words, the language of the Patent Act does not
suggest that the words "machine" or "process" carry limitations
outside their ordinary meaning. See Diehr, 450 U.S. at 182, 101 S.Ct.
at 1054 ("Unless otherwise defined, 'words will be interpreted as
taking their ordinary, contemporary, common meaning.' "). Rather the
Act, by its terms, extends patent protection to "any" machine or
process which satisfies the other conditions of patentability.
II.
In Benson, the Supreme Court encountered the question of whether
a method for converting binary-coded decimals, which was useful in
programming digital computers, was a patentable "process" under
section 101. 409 U.S. at 64, 93 S.Ct. at 254. The Court, by reading
a limitation not found in the statute into the term "process,"
determined the method of conversion did not satisfy section 101.
In Parker v. Flook, 437 U.S. 584, 98 S.Ct. 2522, 57 L.Ed.2d 451
(1978), the Court followed Benson. Flook claimed a method for
updating alarm limits during catalytic conversion of hydrocarbons.
The Court found Flook's method involving mathematical
calculations--though applied to a post-solution use-- unpatentable.
Flook, 437 U.S. at 590, 98 S.Ct. at 2525. Flook clearly limited the
Benson rule to mathematical formulae and mathematical algorithms. Id.
437 U.S. at 585, 587, 589, 590, 591, 592, 594, 595, 98 S.Ct. at 2523,
2524, 2525, 2525, 2526, 2526, 2527, 2528. By mixing the terms
"formula" and "algorithm," 437 U.S. at 585-86, 98 S.Ct. at 2523,
however, Flook further confused the meaning of "mathematical
algorithm." As used by Benson, that term meant "a procedure for
solving a given type of mathematical problem." 409 U.S. at 65, 93
S.Ct. at 254. Thus, an "algorithm" required both a mathematical
problem and a solution procedure. A "formula" does not present or
solve a mathematical problem, but merely expresses a relationship in
mathematical terms. A "formula," even under Benson's definition, is
not an algorithm.
In the wake of Benson, the Court of Customs and Patent Appeals
struggled to implement the algorithm rule. [FN1] Much of the
difficulty sprang from the obscurity of the terms invoked to preclude
patentability--terms like "law of nature," "natural phenomena,"
"formulae," or "algorithm." [FN2] *1063 Benson, 409 U.S. at 65, 67, 93
S.Ct. at 254, 255; Flook, 437 U.S. at 593, 98 S.Ct. at 2527. In the
context of a product's subject matter patentability, Justice
Frankfurter discussed this analytical difficulty:
FN1. See, e.g., In re Christensen, 478 F.2d 1392, 1396, 178 USPQ
35 (CCPA 1973) (Rich, J., concurring) ("The Supreme Court in Benson
appears to have held that claims drafted in such terms are not
patentable--for what reason remaining a mystery."), overruled in part
by In re Taner, 681 F.2d 787, 214 USPQ 678 (1982); In re Johnston, 502
F.2d 765, 773, 183 USPQ 172, 179 (CCPA 1974) (Rich, J., dissenting)
("I am probably as much--if not more--confused by the wording of the
Benson opinion as many others."); rev'd, Dann v. Johnston, 425 U.S.
219, 96 S.Ct. 1393, 47 L.Ed.2d 692 (1976); In re Chatfield, 545 F.2d
152, 157, 191 USPQ 730, 735 (CCPA 1976) (Nonstatutory claims are
"drawn to mathematical problem-solving algorithms or to purely mental
steps."), cert. denied, Dann v. Noll, 434 U.S. 875, 98 S.Ct. 226, 54
L.Ed.2d 155 (1977).
FN2. The Court in Diamond v. Diehr, 450 U.S. 175, 101 S.Ct.
1048, 67 L.Ed.2d 155 (1981), expressly recognized that the term
algorithm "is subject to a variety of definitions." 450 U.S. at 186
n. 9, 101 S.Ct. at 1056 n. 9. Even Benson's definition for
"algorithm" creates legal problems. For instance, the Benson-Tabbot
algorithm worked with numbers, but "solved" a "mathematical problem"
only in a very loose sense. Rather the Benson-Tabbot algorithm
translated symbols from one numerical system to another. Cf. In re
Toma, 575 F.2d 872, 197 USPQ 852 (CCPA 1978) (Using a digital computer
to translate technical languages was not an algorithm.); In re
Freeman, 573 F.2d 1237, 197 USPQ 464 (CCPA 1978) (Using computer to
transcribe alphanumeric characters was not an algorithm.). Moreover
some problems, even if expressed in mathematical terms, are not
mathematical problems. Mathematics, like a language, is a form of
expression. The operation of a machine, the generation of
electricity, the reaction of two chemicals, a baseball batter's swing,
a satellite's orbit-- all are within the descriptive power of
mathematics. The Court of Customs and Patent Appeals recognized this
axiomatic point: However, some mathematical algorithms ... represent
ideas or mental processes and are simply logical vehicles for
communicating possible solutions to complex problems. In re Meyer, 688
F.2d 789, 794, 215 USPQ 193, 197 (CCPA 1982). No wonder the Benson
rule is confusing when electrical, chemical, or mechanical processes
escape scrutiny when expressed in written language, but become suspect
when expressed in the mathematical language. In In re Grams, 888 F.2d
835, 12 USPQ2d 1824 (Fed.Cir.1989), for instance, a medical diagnostic
process was considered an unpatentable "mathematical algorithm" even
though it did not present, or propose a solution to, a mathematical
problem at all.
It only confuses the issue, however, to introduce such terms as
"the work of nature" and the "laws of nature." For these are vague
and malleable terms infected with too much ambiguity and equivocation.
Everything that happens may be deemed "the work of nature," and any
patentable composite exemplifies in its properties "the laws of
nature." Arguments drawn from such terms for ascertaining
patentability could fairly be employed to challenge almost every
patent. Funk Bros. Seed Co. v. Kalo Inoculant Co., 333 U.S. 127,
134-35, 68 S.Ct. 440, 443, 92 L.Ed. 588 (1948) (Frankfurter, J.,
concurring). When attempting to enforce a legal standard embodied in
broad, vague, nonstatutory terms, the courts have floundered.
At length, in In re Freeman, 573 F.2d 1237, 197 USPQ 464 (CCPA
1978) as modified by In re Walter, 618 F.2d 758, 205 USPQ 397 (CCPA
1980), the Court of Customs and Patent Appeals settled on a two-step
test to detect unpatentable algorithms under the Benson rule: First,
the claim is analyzed to determine whether a mathematical algorithm is
directly or indirectly recited. Next, if a mathematical algorithm is
found, the claim as a whole is further analyzed to determine whether
the algorithm is "applied in any manner to physical elements or
process steps," and, if it is, it "passes muster under s 101." In re
Pardo, 684 F.2d 912, 915, 214 USPQ 673, 675-76 (CCPA 1982) (citing In
re Abele, 684 F.2d 902, 214 USPQ 682 (CCPA 1982)). Walter adopted
Flook's implicit limitation of the Benson rule to "mathematical
algorithms." 618 F.2d at 764-65 n. 4. Like Flook, however, Walter
confused "mathematical algorithms" with calculations, formulas, and
mathematical procedures generally. Id.
Although downstream from Benson, this Freeman-Walter fork hid
some of the same unnavigable cross-currents. In the first place, the
term "mathematical algorithm" remained vague. Without a statutory
anchor, this term was buffeted by every judicial wind until its course
was indiscernible. The obscurity of the term "mathematical algorithm"
is evident in two cases. In Pardo, 684 F.2d 912, the court narrowly
limited "mathematical algorithm" to the execution of formulas with
given data. In the same year, the court in In re Meyer, 688 F.2d 789,
215 USPQ 193 (CCPA 1982), sweepingly interpreted the same term to
include any mental process that can be represented by a mathematical
algorithm.
The second part of the test had similar uncertainties. The test
did not suggest how many physical steps a claim must take to escape
the fatal "mathematical algorithm" category. In Abele, 684 F.2d 902,
the court upheld claims applying "a mathematical formula within the
context of a process which encompasses significantly more than the
algorithm alone." Id. at 909. Thus, the court apparently made
compliance with the two-part test a function of the "significance" of
additions to the algorithm--hardly a predictable standard.
The Court of Customs and Patent Appeals later clarified that the
two-part algorithm is not the exclusive test for detecting
unpatentable subject matter. Meyer, 688 F.2d at 796. Indeed, the
court abandoned the two-step test in In re Taner, 681 F.2d 787, 214
USPQ 678 (CCPA 1982).
With the advent of the Court of Appeals for the Federal Circuit,
this court continued to grapple with the inherent vagueness of the
two-part test for unpatentable algorithms. See In re Grams, 888 F.2d
835, 12 USPQ2d 1824 (Fed.Cir.1989); In re Iwahashi, 888 F.2d 1370, 12
USPQ2d 1980 (Fed.Cir.1989). At one point, this court clarified *1064
that failure to satisfy the second prong of the two-part test "does
not necessarily doom the claim." Grams, 888 F.2d at 839. Instead
this court recommended asking the broader question of "What did
applicants invent?" in the context of the claim and its supporting
disclosure. Id. At another point in the same opinion, this court put
the central question in terms of whether "the claim in essence covers
only the algorithm." Id. at 837.
Recognizing the obscurity of "algorithm," this court in Iwahashi
attempted to "take the mystery out of the term": [W]e point out once
again that every step-by-step process, be it electronic or chemical or
mechanical, involves an algorithm in the broad sense of the term.
Since s 101 expressly includes processes as a category of inventions
which may be patented and s 100(b) further defines the word "process"
as meaning "process, art or method, and includes a new use of a known
process, machine, manufacture, composition of matter, or material," it
follows that it is no ground for holding a claim is directed to
nonstatutory subject matter to say it includes or is directed to an
algorithm. This is why the proscription against patenting has been
limited to mathematical algorithms.... 888 F.2d at 1374 (emphasis in
original). Because the Iwahashi claims as a whole described a machine
or a manufacture (which fit within section 101 without regard to the
meaning of "process"), this court in Iwahashi did not have occasion to
resolve conflicts over the legal bounds of "mathematical algorithm."
In sum, the two-part test was cast in the crucible of confusion
created by Benson. If the Benson algorithm rule was the last and
binding word on the meaning of "process" under section 101, this court
would be obligated to follow--regardless of any imprecision or
ambiguity. The Supreme Court, however, has already shown another
reading of the Patent Act.
III.
In Diehr, the Supreme Court adopted a very useful algorithm for
determining patentable subject matter, namely, following the Patent
Act itself. Diehr upheld claims to a process for curing synthetic
rubber which included use of a mathematical computer process. After
setting forth the procedural history of the case, the Supreme Court
stated: In cases of statutory construction, we begin with the language
of the statute. Diehr, 450 U.S. at 182, 101 S.Ct. at 1054. Perhaps
with an eye to the attempts to apply the Benson rule, the Court then
noted: [I]n dealing with the patent laws, we have more than once
cautioned that "courts 'should not read into the patent laws
limitations and conditions which the legislature has not expressed.' "
Id. (citations omitted). Indeed Congress has never stated that
section 101's term "process" excludes certain types of algorithms.
Therefore, as Diehr commands, this court should refrain from employing
judicially-created tests to limit section 101.
With that introduction, the Court proceeded to interpret the
word "process" from section 101. In doing so, the Court briefly
examined the history of patent laws back to 1793. See also
Chakrabarty, 447 U.S. at 308-09, 100 S.Ct. at 2207. The Court summed
up the legislative intent of the patent laws with this broad
admonition: [T]he Committee Reports accompanying the 1952 Act ...
inform us that Congress intended statutory subject matter to "include
anything under the sun that is made by man." S.Rep. No. 1979, 82d
Cong., 2d Sess., 5 (1952); H.R.Rep. No. 1923, 82d Cong., 2d Sess., 6
(1952). Diehr, 450 U.S. at 182, 101 S.Ct. at 1054. This passage
underscores the fallacy of creating artificial limits for the words of
the 1952 Act.
Courts should give "process" its literal and predictable
meaning, without conjecturing about the policy implications of that
literal reading. Cf. Chakrabarty, 447 U.S. at 316-18, 100 S.Ct. at
2211-12. If Congress wishes to remove some processes from patent
protection, it can enact such an exclusion. Again, in the absence of
legislated *1065 limits on the meaning of the Act, courts should not
presume to construct limits. The Supreme Court directed this court to
follow the Act.
With that preface, the Supreme Court in Diehr specifically
limited Benson. In the first place, the Court acknowledged the narrow
definition of "mathematical algorithm" set forth by Benson. 450 U.S.
at 186 n. 9, 101 S.Ct. at 1056 n. 9. Moreover, the Court expressly
stated: Our previous decisions regarding the patentability of
"algorithms" are necessarily limited to the more narrow definition
employed by the Court.... Id. Thus, after Diehr, only a mathematical
procedure for solution of a specified mathematical problem is suspect
subject matter.
The Supreme Court in Diehr also limited Benson to a further
narrow proposition. That narrow proposition supports reliance on the
statutory language of the 1952 Act, rather than a nonstatutory
algorithm rule.
Citing Benson, the Court in Diehr stated: This Court has
undoubtedly recognized limits to s 101 and every discovery is not
embraced within the statutory terms. Excluded from such patent
protection are laws of nature, natural phenomena, and abstract ideas.
Our recent holdings in Gottschalk v. Benson, supra, and Parker v.
Flook, supra, both of which are computer-related, stand for no more
than these long-established principles. 450 U.S. at 185, 101 S.Ct. at
1056. In Taner, 681 F.2d at 791, this court's predecessor said: [I]n
Diehr, the Supreme Court made clear that Benson stands for no more
than the long-established principle that laws of nature, natural
phenomena, and abstract ideas are excluded from patent protection and
that "a claim drawn to subject matter otherwise statutory does not
become nonstatutory because it uses a mathematical formula, computer
program, or digital computer." [Citations omitted.] Thus, Diehr
limited Benson and its progeny to three classes of unpatentable
subject matter--laws of nature, natural phenomena, and abstract ideas.
Indeed, in Chakrabarty, the Court also cited Benson for the
proposition that these three categories are unpatentable. 447 U.S. at
309, 100 S.Ct. at 2207; see also Flook, 437 U.S. at 593, 98 S.Ct. at
2527.
Because the Supreme Court cited Benson in Diehr, 450 U.S. at
185-86, 101 S.Ct. at 1056, this court has doubted whether Diehr
limited the algorithm rule. Grams, 888 F.2d at 838. However, In re
Taner, clearly interprets Diehr as strictly limiting Benson. 681 F.2d
at 789, 791. More importantly, the Supreme Court instructed this
court to apply the language of the 1952 Act without reading
unexpressed limitations into the statute. Diehr, 450 U.S. at 182, 101
S.Ct. at 1054. Finally, to the extent that the Benson rule applies to
mathematical algorithms in the wake of Diehr, the Supreme Court
defined "mathematical algorithm" very narrowly.
By strictly limiting Benson, the Supreme Court signalled a
change in the focus for patentability from the algorithm rule to the
statutory standards of the Patent Act. The Supreme Court confined
Benson to a narrow proposition which certainly does not preclude
patentability of the '459 patent's heart attack risk detection
process.
The '459 Patent
The '459 patent discloses an apparatus and a method for
analyzing electrocardiograph signals to detect heart attack risks.
The apparatus is a machine and is covered by the Iwahashi rule. The
method converts an analog signal to a digital signal which passes, in
reverse time order, through the mathematical equivalent of a filter.
The filtered signal's amplitude is then measured and compared with a
predetermined value.
The '459 invention manipulates electrocardiogram readings to
render a useful result. While many steps in the '459 process involve
the mathematical manipulation of data, the claims do not describe a
law of nature or a natural phenomenon. Furthermore, the claims do not
disclose mere abstract *1066 ideas, but a practical and potentially
life-saving process. Regardless of whether performed by a computer,
these steps comprise a "process" within the meaning of section 101.
The district court granted summary judgment in favor of
Corazonix because "the claims of the '459 patent are drawn to a
nonstatutory mathematical algorithm and, as such, are unpatentable
pursuant to the provisions of 35 U.S.C. s 101." This erroneous
conclusion illustrates the confusion caused by Benson and its progeny.
This conclusion is erroneous for several reasons. First, even
if mathematical algorithms are barred from patentability, [FN3] the
'459 patent as a whole does not present a mathematical algorithm. The
'459 patent is a method for detecting the risk of a heart attack, not
the presentation and proposed solution of a mathematical problem. In
Diehr, the Supreme Court viewed the claims as "an industrial process
for molding of rubber products," not a mathematical algorithm. 450
U.S. at 192-93, 101 S.Ct. at 1060. The '459 patent's claims as a
whole disclose a patentable process.
FN3. The Court in Diehr stated: "we concluded that such an
algorithm, or mathematical formula, is like a law of nature, which
cannot be the subject of a patent." 450 U.S. at 186, 101 S.Ct. at
1056 (emphasis added). In fact, a mathematical algorithm does not
appear in nature at all, but only in human numerical processes. A law
of nature is indeed not patentable, but for reasons unrelated to the
meaning of "process." A law of nature, even if a process, is not
"new" within the meaning of s 101. Moreover, in Sarker, this court's
predecessor gave another reason a law of nature cannot satisfy section
101. In re Sarker, 588 F.2d 1330, 1333, 200 USPQ 132, 137 (CCPA
1978). In sum, the Patent Act excludes laws of nature from patent
protection even without a strained explanation excluding laws of
nature from the meaning of "process." It is difficult to determine
how or why mathematical algorithms are "like" laws of nature.
Second, the '459 patent does not claim a natural law, abstract
idea, or natural phenomenon. Diehr limited the Benson rule to these
three categories, none of which encompass the '459 patent.
Finally, and most important, Diehr refocused the patentability
inquiry on the terms of the Patent Act rather than on non-statutory,
vague classifications. Under the terms of the Act, a "process"
deserves patent protection if it satisfies the Act's requirements.
The '459 patent claims a "process" within the broad meaning of section
101. Therefore, this court must reverse and remand.
CONCLUSION
When determining whether claims disclosing computer art or any
other art describe patentable subject matter, this court must follow
the terms of the statute. The Supreme Court has focused this court's
inquiry on the statute, not on special rules for computer art or
mathematical art or any other art.
The claims of the '459 patent define an apparatus and a process.
Both are patentable subject matter within the language of section 101.
To me, the Supreme Court's most recent message is clear: when all else
fails (and the algorithm rule clearly has), consult the statute. On
this basis, I, too, would reverse and remand.