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Canadian Patent Law Benchbook
Donald M. Cameron
Toronto: Carswell, 2012
[© 2012 Thomson Reuters Canada Limited. Reproduced by permission of Carswell, a division of Thomson Reuters Canada Limited.]
Excerpt: pp. 303-4, 381-2, 398-403
[Footnotes have been converted to endnotes.]
The question to be asked in construing a claim of a patent is:
“What would the claim have meant to a skilled reader as of the relevant date?” (Chapter 6.1).
Claim construction consists of the following:
- Read the patent as a whole, and construe the claims in the context of the patent (Chapter 126.96.36.199).
- If the disclosure expressly defines certain terms to have certain meanings, use those definitions when interpreting the claims (Chapter 188.8.131.52.1).
- The relevant date for construing the patent claims is either:
a) The date of issuance of the patent, for patents applied for before October 1, 1989; or
b) the date of publication of the patent application, for patents applied for on or after October 1, 1989 (Chapter 184.108.40.206).
- Read the patent as if you were the person to whom it was addressed. Except for terms expressly defined in the patent, give the terms in the claim the ordinary meaning they would have had to such person as of the relevant date (Chapter 6.7.1).
- To determine whether a claim element is essential or not, ask (Chapter 6.8.1):
- Was it obvious to the skilled reader at the time the patent was published that a variant of a particular element would not make a difference to the way in which the invention works? If modifying or omitting the element changes the way the invention works, and that was obvious at the relevant date, then the element is essential; (Chapter 6.8.2) or
- According to the intent of the inventor, expressed or inferred from the claims, was a particular element essential irrespective of its practical effect? If the element appears to have been intended to be essential, then the element is essential (Chapter 6.8.3).
If the claim element was not found to be essential under either Q1 or Q2, then the element is non-essential (Chapter 6.8.4).
. . . .
6.8.1 A Purposive Construction of Free World
The Free World test is explicitly disjunctive, whereas Catnic and Improver asked questions sequentially and dependently. In addition, unlike Justice Hoffman in Improver, Binnie J. did not provide specific questions, answers and directions as to how essentiality or non-essentiality were to be determined in applying the test.
In order for the disjunctive questions in Free World to be consistent with the con- junctive questions asked in Catnic and Improver (both of which Binnie J. approved) the questions for determining essentiality must be:
3. Was it obvious to the skilled reader at the time the patent was published that a variant of a particular element would not make a difference to the way in which the invention works? If modifying or omitting the element changes the way the invention works, and that was obvious at the relevant date, then the element is essential; or
4. According to the intent of the inventor, expressed or inferred from the claims, was a particular element essential irrespective of its practical effect? If the element appears to have been intended to be essential, then the element is essential.
Thus if either Question 1 or Question 2 established that the claim element is essen- tial, then it is essential. In order to be non-essential, it must be found not to be essential under both questions.
This interpretation is consistent with the approach taken by the Federal Court of Appeal in Halford v. Seed Hawk Inc.:
An element may be found to be essential on the basis of the intent of the inventor as expressed or inferred from the claims, or on the basis of evidence as to whether it would have been obvious to a skilled worker at the time the patent was published that a variant of a particular element would make a difference to the way in which the invention works (Free World at paragraphs 31 and 55).
Although the Free World test permits departing from the wording of the claims, Justice Binnie suggested that it be done sparingly:
The patent owner, competitors, potential infringers and the public generally are thus entitled to clear and definite rules as to the extent of the monopoly conferred. This in turn requires that the subjective or discretionary element of claims interpretation (e.g., the elusive quest for “the spirit of the invention”) be kept to the minimum, consistent with giving “the inventor protection for that which he has actually in good faith invented” (Western Electric Co. v. Baldwin International Radio of Canada,  S.C.R. 570 at p. 574). Predictability is achieved by tying the patentee to its claims; fairness is achieved by interpreting those claims in an informed and purpo- sive way. [emphasis added]
. . . .
6.8.4 An Inconsistency in Free World
Although Justice Binnie followed and endorsed Catnic, Improver and O’Hara, there is one portion of the judgment in Free World that is discordant with the conjunctive two step approach of the previous cases. After expressly stating the test of essentiality/non-essentiality, Justice Binnie later restated his test as a test of non- essentiality as follows:
It would be unfair to allow a patent monopoly to be breached with impunity by a copycat device that simply switched bells and whistles, to escape the literal claims of the patent. Thus the elements of the invention are identified as either essential elements (where substitution of another element or omission takes the device outside the monopoly), or non-essential elements (where substitution or omission is not necessarily fatal to an allegation of infringement). For an element to be considered non-essential and thus substitutable, it must be shown either (i) that on a purposive construction of the words of the claim it was clearly not intended to be essential, or (ii) that at the date of the publication of the patent, the skilled addressees would have appreciated that a particular element could be substituted without affecting the working of the invention, i.e. had the skilled worker at that time been told of both the element specified in the claim and the variant and “asked whether the variant would obviously work in the same way”, the answer would be yes . . . [emphasis added]
If Justice Binnie meant exactly what he said at this portion of the judgment, his test would bifurcate the questions in Catnic, Improver and O’Hara into two, mutually independent questions, either of which could establish that a claim element was non-essential:
Q#1: (ii) that at the date of the publication of the patent, the skilled addressees would have appreciated that a particular element could be substituted without affecting the working of the invention.
This is the first question in Catnic and Improver. If this question was met, then the claim element would have had equivalents at the date of publication. If this was meant to be treated as an independent question, then it would not matter whether a clear intention was expressed or inferred from the claim that the element was essential, or even an express statement in the disclosure said that the element was essential. Under this interpretation, there could never be “self-inflicted wound” as there was in O’Hara. The test under this circumstance would allow for all equivalents known at the publication date to be variants included in the claim, no matter how specific the language of the claim. Such test would be contrary to Justice Binnie’s direction that the inquiry be “. . . anchored in the language of the claims . . .” otherwise “. . . the court may be heading into unknown waters without a chart.
An example of an application of this reading of Free World can be found in Pfizer Canada Inc. v. Novopharm Ltd., discussed in more detail below in Chapter 6.9.1 where the Court considered “wet granulation” to be included in a claim that expressly referred to “dry granulation” because the Court answered only the first Free World question and considered them to be obviously substitutable at the publication date.
Q#2: (i) that on a purposive construction of the words of the claim it was clearly not intended to be essential
This is a version of the second question in Catnic, the third question in Improver and the analysis that resulted in the “self-inflicted wound” in O’Hara. If this was treated as an independent test, a variant could radically change the way the invention worked (i.e., be essential under the first Catnic and Improver questions) but if the Court considered that the inventor’s intention was to include the variant, then, under this test, the element would be found non-essential.
In contrast, in Catnic, Improver and O’Hara, the Courts effectively said “Even if the variant does not change the way the invention works, if the patentee clearly considered the claim element to be essential, then it is to be considered essential.
The contrast in logic between these questions in Free World and those in Catnic and Improver is evident upon a comparison of their logic in Catnic and Improver and the interpretation of Free World given in Chapter 6.8.1 above, as illustrated in Appendix “A” to this Chapter.
Binnie J. quoted Improver with approval. In Improver, Hoffman J. stated that the second Catnic question (the third Improver question) the question that raised the question of construction (as compared to the factual background against which the claim is to be construed):
It is worth noticing that Lord Diplock’s first two [Catnic] questions, although they cannot sensibly be answered without reference to the patent, do not primarily involve questions of construction: whether the variant would make a material difference to the way the invention worked and whether this would have been obvious to the skilled reader are questions of fact. The answers are used to provide the factual background against which the specification must be construed. It is the third question which raises the question of construction and Lord Diplock’s formulation makes it clear that on this question the answers to the first two questions are not conclusive. Even a purposive construction of the language of the patent may lead to the conclusion that although the variant made no material difference and this would have been obvious at the time, the patentee for some reason was confining his claim to the primary meaning and excluding the variant. If this were not the case, there would be no point in asking the third [Improver] question at all.
If Binnie J. intended his test to be consistent with Catnic and O’Hara, it should have been expressed as a test for essentiality (rather than non-essentiality) and the negatives turned to positives, as follows:
For an element to be considered essential and thus non-substitutable, it must be shown either:
(i) that on a purposive construction of the words of the claim it was clearly intended to be essential, or
(ii) that at the date of the publication of the patent, the skilled addressees would have appreciated that a particular element could not be substituted without affecting the working of the invention, . . .
Such test would be consistent with Catnic and O’Hara in that if either question found the element to be essential, then it would be essential and if both questions found the element not to be essential, then the element would be non-essential.
Justice Binnie appears to have repeated this apparent inconsistency in logic at another point of the decision. In dealing with the onus of proving that a variant was obvious at the publication date, Justice Binnie stated:
In my view, Catnic, supra, and O’Hara, supra, were correct to put the onus on the patentee to establish known and obvious substitutability at the date of publication of the patent. If the patentee fails to discharge that onus, the descriptive word or expression in the claim is to be considered essential unless the context of the claims language otherwise dictates. [emphasis added]
The first part of the italicized quote above is consistent with Catnic and Improver. The latter part is not.
Having found the claim element to be essential under the first question, the latter part of the sentence appears to be saying it is essential unless the context of the claims otherwise dictates (i.e., the element appears to be non-essential based on the wording of the claims — the paragraph (e)(iv) test). The test thus contemplates the possibility of the claim element being considered essential under the first question but non-essential under the second question, and the element therefore being non-essential. This is contrary to Catnic and Improver which asked the second question only after finding the element to be, at first blush, non-essential under the first question.
Perhaps the unusual nature of the proposed scenario renders it of minimal concern: a situation where the patentee has claimed something that, if changed, materially changes the way the invention works, but is referred to expressly as a claim element, yet the Court concludes that the inventor did not intend it to be essential, based on a determining such intent from the claim.
In 2010, Justice Gauthier said, in addressing this part of the Free World decision, that this sentence cannot be construed as meaning that the Supreme Court found the third question in Improver to be irrelevant. Expressed as a positive: the Supreme Court still required the third question in Improver to be asked.
Even in Free World, Justice Binnie himself applied the third Improver question, whether or not the variant affected the way the invention worked:
 In O’Hara, supra, the Federal Court of Appeal held that a patent for a pill coating machine that specified a flexible exhaust could not be interpreted to cover a machine that fulfilled the same function and contained all of the other essential elements but which utilized a fixed exhaust. Pratte J.A., for the court, considered it important that the patentee had specified “exhaust inlet flexibly biased”, and must be taken to have attached significance to the words chosen (at p. 7):
. . . unless it be obvious that the inventor knew that a failure to comply with that requirement would have no material effect upon the way the invention worked.
Pratte J.A. also stated:
A court must interpret the claims; it cannot redraft them. When an inventor has clearly stated in the claims that he considered a requirement as essential to his invention, a court cannot decide otherwise for the sole reason that he was mistaken.
To the same effect see J. K. Smit & Sons, supra, per Duff C.J., at p. 285.
 The facts of O’Hara have an echo in the facts of this case. Claim 1 of the ‘156 patent stipulates the “said magnetization coil being stationary” during treatment. Whether the magnetization coil is stationary may or may not affect the way the device works, but the inventor has explicitly so stipulated.
Had Justice Binnie truly intended the test of non-essentiality to be satisfied by either Catnic question, the last sentence of paragraph  of Free World would be non-sensical: if the magnetization coil had not affected the way the device worked, then it would have been non-essential and the second question would not have to have been asked. By Justice Binnie stated that the inventor had “explicitly so stipulated” in the context of this part of Free World, suggests that Justice Binnie intended to affirm logic of the O’Hara decision and that the test be conjunction (“and”) not disjunctive (“or”).
In Free World, Justice Binnie asked both Catnic questions. He decided that the claims clearly required “circuit means” finding that claim element to be “essential” under both questions:
- He appears to have decided that the defendant’s microcontroller performed the same or a similar function as the claimed “circuit means”, but performed that function in a “very different way”. Under the first Catnic question, the “circuit means” would be considered “essential”;
- With respect to the second Catnic question, Justice Binnie stated:
Moreover, there is no reason to think the inventor didn’t mean what he said, or considered the use of “circuit means” a non-essential element of the claims, or intended to claim more broadly than “circuit means” and thereby put at risk for “covetous claiming” the validity of the patents.
Likewise, under the second Catnic question, the “circuit means” would be considered “essential”.
. . .
353 Free World Trust c. E ́lectro Sante ́ Inc., 2000 CarswellQue 2728, 2000 CarswellQue 2731, 9 C.P.R. (4th) 168 (S.C.C.) at para. 31, per Binnie, J. The disjunctive “or” was noted by Harrington J. in Biovail Pharmaceuticals Inc. v. Canada (Minister of National Health & Welfare) (2005), 37 C.P.R. (4th) 487 (F.C.) at 503 [C.P.R.], para. 46, per Harrington J. while he applied the Improver questions in para. 44.
354 See Appendix “A” for a comparison of the logic in Catnic, Improver and Free World.
355 Halford et al v. Seed Hawk Inc. et al, 2006 FCA 275, 2006 CarswellNat 2397, 2006 CarswellNat 4150, (F.C.A. per Sexton, Sharlow and Malone JJ.A.) at para. 13.
356 Free World Trust c. E ́lectro Sante ́ Inc., 2000 CarswellQue 2728, 2000 CarswellQue 2731, 9 C.P.R. (4th) 168 (S.C.C.) at para. 43, per Binnie, J.
. . .
427 Free World Trust c. E ́lectro Sante ́ Inc., 2000 CarswellQue 2728, 2000 CarswellQue 2731, 9 C.P.R. (4th) 168 (S.C.C.) at para. 55, per Binnie, J.
428 This would be analogous (in one respect) to the U.S. Doctrine of Equivalents in that the claims would cover that which is claimed and all equivalents of each element claimed: Pennwalt Corp. v. Durand-Wayland, Inc., 833 F.2d 934 (Fed. Cir., 1987); Warner-Jenkinson Co., Inc. v. Hilton Davis Chemical Co., 520 U.S. 17 (1997) at 37, per Thomas J. It would differ in that no element could be omitted.
429 Whirlpool Corp. v. Camco Inc., 2000 CarswellNat 2846, 2000 CarswellNat 2861, 9 C.P.R. (4th) 129 (S.C.C.) at 190 [C.P.R.], paras. 45–46, per Binnie, J.; reconsideration re- fused 2001 CarswellNat 283, 2001 CarswellNat 284 (S.C.C.).
430 Pfizer Canada Inc. v. Novopharm Ltd., 2005 CarswellNat 5544, 2005 CarswellNat 3114, 42 C.P.R. (4th) 502 (F.C.) at para. 54, per Blanchard J.
431 Pfizer Canada Inc. v. Novopharm Ltd.,, 2005 CarswellNat 5544, 2005 CarswellNat 3114, 42 C.P.R. (4th) 502 (F.C.) at para. 77, per Blanchard J.
432 Compare the logic of this test, illustrated in Figure 4 in Appendix “A” with the “purpo- sive” interpretation of Free World given above in Chapter 6.8, Figure 3 in Appendix “A” and that of Catnic and Improver, given in Figures 1 and 2 of Appendix “A” respectively.
433 Improver Corp. v. Remington Consumer Products Ltd. (1989),  F.S.R. 181 (Eng. Patents Ct.) at 190; Canamould Extrusions Ltd. v. Driangle Inc., 2003 CarswellNat 554, 2003 CarswellNat 1905, 25 C.P.R. (4th) 343 (Fed. T.D.); affirmed 2004 CarswellNat 970, 2004 CarswellNat 386, 30 C.P.R. (4th) 129 (F.C.A.) at 142 [C.P.R.], para. 25.
434 Free World Trust c. E ́lectro Sante ́ Inc., 2000 CarswellQue 2728, 2000 CarswellQue 2731, 9 C.P.R. (4th) 168 (S.C.C.) at para. 5, per Binnie, J.
435 “If the patentee fails to discharge that onus, the descriptive word or expression in the claim is to be considered essential . . .”
436 “. . . unless the context of the claims language otherwise dictates.” 401
437 See Chapter 6.3.3 above:
3. Would the reader skilled in the art nevertheless have understood from the lan- guage of the claim that the patentee intended that strict compliance with the primary meaning was an essential requirement of the invention? If yes, then the variant is outside the claim.
438 Bauer Hockey Corp. v. Easton Sports Canada Inc., 2010 FC 361, 2010 CarswellNat 3031, 2010 CarswellNat 796 (F.C.) at para. 144, per Gauthier J.; affirmed 2011 CarswellNat 4827, 2011 CarswellNat 561 (F.C.A.). Although the inventor knew that the tendon guard could be attached in an overlapping fashion [substitutable, and therefore non-essential under the first Improver question], it was also evident that he chose to limit his monopoly to tendon guards attached in a side-by-side fashion [intention of the inventor as expressed in the claims, and therefore essential under the second Improver question].
439 Free World Trust c. E ́lectro Sante ́ Inc., 2000 CarswellQue 2728, 2000 CarswellQue 2731, 9 C.P.R. (4th) 168 (S.C.C.) at paras. 59–60, per Binnie, J.
440 Free World Trust c. E ́lectro Sante ́ Inc., 2000 CarswellQue 2728, 2000 CarswellQue 2731, 9 C.P.R. (4th) 168 (S.C.C.) at para. 73, per Binnie, J.