Inventive step and non-obviousness

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The inventive step and non-obviousness reflect a general patentability requirement present in most patent laws, according to which an invention should be sufficiently inventive — i.e., non-obvious — in order to be patented.[1] In other words, "[the] nonobviousness principle asks whether the invention is an adequate distance beyond or above the state of the art."[2]

The expression "inventive step" is predominantly used in Europe, while the expression "non-obviousness" is predominantly used in United States patent law.[1] The expression "inventiveness" is sometimes used as well.[3] Although the basic principle is roughly the same, the assessment of the inventive step and non-obviousness varies from one country to another. For instance, the practice of the European Patent Office (EPO) differs from the practice in the United Kingdom.


The purpose of the inventive step, or non-obviousness, requirement is to avoid granting patents for inventions which only follow from "normal product design and development", in order to eventually achieve a proper balance between the incentives provided by the patent system, namely encouraging innovation, and the social cost of the patent system, namely conferring temporary monopolies.[4]



The requirement for non-obviousness is codified under section 28.3 of the Patent Act (R.S.C., 1985, c. P-4).[5]

28.3 The subject-matter defined by a claim in an application for a patent in Canada must be subject-matter that would not have been obvious on the claim date to a person skilled in the art or science to which it pertains, having regard to
(a) information disclosed more than one year before the filing date by the applicant, or by a person who obtained knowledge, directly or indirectly, from the applicant in such a manner that the information became available to the public in Canada or elsewhere; and
(b) information disclosed before the claim date by a person not mentioned in paragraph (a) in such a manner that the information became available to the public in Canada or elsewhere.

The Supreme Court of Canada affirmed the test for non-obviousness laid out in Windsurfing International Inc. v. Tabur Marine (Great Britain) Ltd.[6] in Apotex Inc. v. Sanofi‑Synthelabo Canada Inc.:

  1. Identify the notional "person skilled in the art" and identify the relevant common general knowledge of that person;
  2. Identify the inventive concept of the claim in question or if that cannot readily be done, construe it;
  3. Identify what, if any, differences exist between the matter cited as forming part of the "state of the art" and the inventive concept of the claim or the claim as construed;
  4. Viewed without any knowledge of the alleged invention as claimed, do those differences constitute steps which would have been obvious to the person skilled in the art or do they require any degree of invention?

European Patent Convention (EPC)[edit]

Pursuant to Article 52(1) in conjunction with Article 56, first sentence, EPC, European patents shall be granted for inventions which, among other things, involve an inventive step, that is, the invention, having regard to the state of the art, must not be obvious to a person skilled in the art.

Problem-solution approach[edit]

The Examining Divisions, the Opposition Divisions, and the Boards of Appeal of the EPO almost always apply the "problem-solution approach" in order to decide whether an invention involves an inventive step. The approach consists in:

  1. identifying the closest prior art, the most relevant prior art, or at least a realistic starting point;
  2. determining the objective technical problem, that is, determining, in the view of the closest prior art, the technical problem which the claimed invention addresses and successfully solves; and
  3. examining whether or not the claimed solution to the objective technical problem is obvious for the skilled person in view of the state of the art in general.

This last step is conducted according to the "could-would approach". Pursuant to this approach, the question to address in order to assess whether the invention involves an inventive step is the following (the question is the climax of the problem-solution approach):

Is there any teaching in the prior art, as a whole, that would, not simply could, have prompted the skilled person, faced with the objective technical problem formulated when considering the technical features not disclosed by the closest prior art, to modify or adapt said closest prior art while taking account of that teaching [the teaching of the prior art, not just the teaching of the closest prior art], thereby arriving at something falling within the terms of the claims, and thus achieving what the invention achieves?

If the skilled person would have been prompted to modify the closest prior art in such a way as to arrive at something falling within the terms of the claims, then the invention does not involve an inventive step.

The point is not whether the skilled person could have arrived at the invention by adapting or modifying the closest prior art, but whether he would have done so because the prior art incited him to do so in the hope of solving the objective technical problem or in expectation of some improvement or advantage. This must have been the case for the skilled person before the filing or priority date valid for the claim under examination.

For a discussion of the inventive step test for "software patents" and "computer-implemented inventions" under the EPO case law, see also "Inventive step test" section in Software patents under the EPC.

United Kingdom[edit]

A set of rules regarding the approach taken by the United Kingdom courts was laid out by the Court of Appeal in Windsurfing International Inc. v Tabur Marine (GB) Ltd. [1985] RPC 59, in determining the requirements for inventive step:

  1. Identifying the inventive concept embodied in the patent;
  2. Imputing to a normally skilled but unimaginative addressee what was common general knowledge in the art at the priority date;
  3. Identifying the differences if any between the matter cited and the alleged invention; and
  4. Deciding whether those differences, viewed without any knowledge of the alleged invention, constituted steps which would have been obvious to the skilled man or whether they required any degree of invention.

This test has been slightly reworked in the more recent Court of Appeal case Pozzoli Spa v BDMO SA & Anor [2007] EWCA Civ 588 (22 June 2007) [7]

  1. (a) Identify the notional "person skilled in the art", (b) Identify the relevant common general knowledge of that person;
  2. Identify the inventive concept of the claim in question or if that cannot readily be done, construe it;
  3. Identify what, if any, differences exist between the matter cited as forming part of the "state of the art" and the inventive concept of the claim or the claim as construed;
  4. Viewed without any knowledge of the alleged invention as claimed, do those differences constitute steps which would have been obvious to the person skilled in the art or do they require any degree of invention?

In Schlumberger Holdings Ltd versus Electromagnetic Geoservices AS [2010] EWCA Civ 819 (28 July 2010), the Court of Appeal clarified that the fictional skilled addressee (which may be a skilled team) used for determining inventive step can vary from the one used for determining claim construction or sufficiency.

United States[edit]

"Non-obviousness" is the term used in US patent law to describe one of the requirements that an invention must meet to qualify for patentability, codified in 35 U.S.C. §103. One of the main requirements of patentability there is that the invention being patented is not obvious, meaning that a "person having ordinary skill in the art" (PHOSITA) would not know how to solve the problem at which the invention is directed by using exactly the same mechanism. Since the PHOSITA standard turned to be too ambiguous in practice, the US Supreme Court provided later two more useful approaches which currently control the practical analysis of non-obviousness by patent examiners and courts: Graham et al. v. John Deere Co. of Kansas City et al., 383 U.S. 1 (1966) gives guidelines of what is "non-obvious", and KSR v. Teleflex (2006) gives guidelines of what is "obvious".

Historical development[edit]

Constitutionally, the non-obviousness requirement is established by Article 1, Section 8, Clause 8: "The Congress shall have the power … to promote the Progress of Science .., by securing for limited Times to … Inventors the exclusive Right to their … Discoveries". The phrase to promote the Progress of Science defines the purpose of the patent system, which is to encourage private investments into fundamental science research rather than to grant monopoly on something that is taken from a public domain (or on something that limits the opportunities for doing research, e.g. research tools are not patentable). The Progress of Science requirement constitutionally validates the pragmatic approach to non-obviousness described below. The word Discoveries establishes the level to which the contribution to the Progress of Science must rise to deserve the temporary monopoly. Despite the guidelines set by the Founding Fathers in the US Constitution, it took over 200 years to develop practical criteria of what Discoveries is.[citation needed]

1790-1850: The Early Days[edit]

The first patent statute enacted by the Congress in 1790 required patentable inventions or discoveries to be "sufficiently useful and important". One can interpret important as important for the Progress of Science since the importance for economy is stated by useful.[citation needed] The next Patent Act of 1793 did not have the important language but stated that "simply changing the form or the proportions of any machine, or compositions of matter, in any degree, shall not be deemed a discovery." (This statement was actually adopted from French Patent Law of 1791). This was echoed in Thomas Jefferson's 1814 letter explaining that changing material, for example, from cast iron to wrought iron was insufficient for patentability.[8]

The difficulty of formulating conditions for patentability was heightened by the generality of the constitutional grant and the statutes implementing it, together with the underlying policy of the patent system that "the things which are worth to the public the embarrassment of an exclusive patent," as Jefferson put it, must outweigh the restrictive effect of the limited patent monopoly. The inherent problem was to develop some means of weeding out those inventions which would not be disclosed or devised but for the inducement of a patent.[9] Jefferson actually foresaw the possibility of patent trolls and sought a mechanism to exclude those patents which only value is to harass producers.[citation needed] Merges and Duffy[10] regret that "the inducement standard was not influential in the legal doctrine, and its absence from subsequent case law raises one of the great unanswered questions of patent law: How can courts continue to ignore a seemingly reasonable and theoretically solid approach to determining patentability?"

The 1836 Patent Act did not have the "simply changing" language but stated instead that the Commissioner of Patents was authorized to issue a patent for any "sufficiently used and important" invention or discovery.

The US Supreme Court considered the issue of inventiveness/non-obviousness/discovery for the first time in 1822 in Evans v. Eaton (20 US 356,431) when it approved the interpretation of a lower court that a patentable improvement must involve a change in the "principle of the machine" not "a mere change in the form or proportions". Currently, such variations are usually interpreted as a lack of novelty not of an inventive step.

1851-1951: Struggles to find practical criteria[edit]

The issue of non-obviousness reached the US Supreme Court again in 1851 in Hotchkiss v. Greenwood. The question was whether a substitution of known door knob materials such metal or wood for a new material—porcelain—deserved a patent. The court concluded that "the improvement in the work of a skillful mechanic, not that of the inventor" and invalidated the patent. Such approach foresees the line of thought which was later formulated as the PHOSITA (person having ordinary skill in the art) approach to the analysis of inventiveness. Despite beginning to develop the PHOSITA approach, the Court did not give practical means to determine what how much inventiveness deserves a patent. It is worth noting here that Eaton and Hotchkiss, respectively, illustrate the heretofore existing trend to state the appropriate inventiveness by defining both what is obvious (lacks an inventive step / discovery) and what is non-obvious (has an inventive step / discovery).

During the period from 1851 to 1951, several new cases related to the non-obviousness of claimed subject matter in patents reached the Supreme Court. One noteworthy case is Rubber-Tip Pencil Co. v. Howard 87 U.S. (20 Wall.) 498 (1874), in which the Supreme Court invalidated a patent on a pencil with a rubber eraser cap on the theory that everyone knows rubber will stick to wood inserted into a hole in the rubber.

However, during that time the Courts struggled to find both the required levels of inventiveness and obviousness and practically useful criteria to measure these levels. One notable example of this struggle is the 1941 US Supreme Court case of Cuno Engineering v. Automatic Devices Corp., which was said to establish the Flash of Genius doctrine as a test of patentability of an invention: "the new device must reveal the flash of creative genius, not merely the skill of the calling". The Flash of Genius approach was thought to have shifted the analysis of inventiveness from importance and from PHOSITA to the state of mind of the inventor; it caused uproar in the patent law community as courts struggled to find alternative approaches.[citation needed]

One notable example of this struggle is the positions of Justice Douglas in Great Atlantic & Pacific Tea Co. v. Supermarket Equipment Corp.[citation needed] in 1950, where he opined that to deserve a patent, an invention "had to serve the end of science—to push back the frontiers of chemistry, physics, and the like"; while two years prior in Funk Bros. Seed Co. v. Kalo Inoculant Co.[citation needed] he stated that the discovery of a new natural principal—is not patentable of itself, "however ingenious the discovery of this natural principle may have been." This position raised issues as to a need to establish the boundary of a patentable domain not only with routine improvements but also with major advancements in science, i.e. creating too much monopoly which may impede rather that promote the Progress of Science. Currently, the latter boundary is established via the requirement for patent-eligible subject matter (research tools, scientific theories and laws are not patent eligible) while the issue of how much inventiveness is required to deserve a patent is defined via the non-obviousness requirement.

The trend that started to develop around 1950 (and dominates today) was to require disclosure of an element of discovery while granting patent monopoly on only one or a few applications that the discoverer came up with before the very first disclosure becomes published. The US Supreme Court's decision in Great Atlantic & Pacific Tea Co. v. Supermarket Equipment Corp.[citation needed] in 1950 is often considered the high-water mark of the pragmatic approach as the Court reversed the patent grant of a commercially successful but very simple mechanical device as merely a "gadget." Based on its decision that a combination "which only unites old elements with no change in their respective functions" is unpatentable because such a patent would "obviously withdraw what already in known into the field of its monopoly and diminish . . . the resources available to skillful men." [11] As a practical test for the pragmatic approach for lower courts to use, the Supreme Court proposed "unusual or surprising consequences" from the combination of old elements: "[O]nly when the whole in some way exceeds the sum of its parts is the accumulation of old devices patentable." Although the time validated the pragmatic approach (does the patent promote the progress of science or does it take away from the public domain), the for- criterion of "unusual or surprising consequences" turned out to be too ambiguous and too high in practice. On the other hand, the against-criterion for a combination that "only unites old elements with no change in their respective functions" has been useful in practice ever since. However, neither the pragmatic approach nor the "unusual or surprising consequence" criterion received further development at that time, because the Congress took in 1952 a different approach to determining non-obviousness going back to a subjective factor similar to the inventor’s (called PHOSITA) state-of-mind.

1952-1960: Phosita[edit]

In order to reduce the impact of non-obviousness on patentability, to eliminate the "Flash of genius" test, and to provide a more fair and practical way to determine whether the invention disclosure deserves a patent monopoly, the Congress took the matter in its own hands and enacted the Patent Act of 1952 35 U.S.C. Section § 103 reads:

The latter sentence about the manner was added in order to overrule the flash of genius test.[citation needed] The Patent Act of 1952 added 35 U.S.C. § 103, which effectively codified non-obviousness as a requirement to show that an idea is suitable for patent protection. The section essentially requires a comparison of the subject matter sought to be patented and the prior art, to determine whether or not the subject matter of the patent as a whole would have been obvious, at the time of the invention, to a Person having ordinary skill in the art a.k.a. PHOSITA. (Similar criteria were enacted and are currently used in many other countries.) Clark held that the Congress, in passing the Act, intended to codify and clarify the common law surrounding the Patent Act by making explicit the requirement of non-obviousness. However, this test turned out be ambiguous and of little help in practice since PHOSITA does not exist.

1960-1989: The Adams trilogy & Graham factors[edit]

The Supreme Court soon gave more practical interpretation of the Patent Act of 1952. It followed the approach it started in Great Atlantic with the rejection rule for a combination that "only unites old elements with no change in their respective functions" and soon added acceptation rules. It was done it was is now referred to as the "Adams trilogy": Calmar v. Cook Chemical (1964),[9] Graham v. John Deere Co. (1966), and United States v. Adams (1966).

In Graham v. John Deere Co.,[12] the Court held that § 103 required a determination of the following questions of fact to resolve the issue of obviousness:

  1. the scope and content of the prior art;
  2. the level of ordinary skill in the art;
  3. the differences between the claimed invention and the prior art; and

In addition, the Court mentioned "secondary considerations" which could, when appropriate, serve as evidence of non-obviousness. They (along with of Great A.&P. Tea's rejection rule for a combination that "only unites old elements with no change in their respective functions") constitute what is a practically useful approach to the determination of what claimed invention is non-obvious, and they are commonly referred to as the "Graham factors":

  1. commercial success resulting from the device's inventive aspect;
  2. long felt but unsolved needs; and
  3. persistent failure of others.

United States v. Adams[citation needed](1966) is a particularly noteworthy case where a single inventor working in his garage on a primary Mg/CuCl/Cu battery won a patent infringement case against the US government in the Supreme Court based primarily on the Graham factors (e.g. repeated failures of others). In the non-obviousness trilogy the Supreme Court further developed positive secondary of non/obviousness in addition to the Graham factors as negative secondary considerations, but noted that the secondary factors could not overcome a strong case of obviousness.

In United States v. Adams, [t]he Court recognized that when a patent claims a structure already known in the prior art that is altered by the mere substitution of one element for another known in the field, the combination must do more than yield a predictable result. In Anderson’s-Black Rock, Inc. v. Pavement Salvage Co.[citation needed] (1969), the two pre-existing elements in combination did no more than they would have accomplished in separate, sequential operation.

Particularly noteworthy was Sakraida v. AG Pro, Inc.[citation needed] (1976), the a unanimous Court found a claimed invention (a water flush system to remove cow manure from the floor of a dairy barn) obvious because it "simply arranges old elements without "producing a new or different function" , although "doubtless a matter of great convenience, producing a desired result in a cheaper and faster way, and enjoying commercial success."[10] This is an important precedent because it reversed the 1st Graham’s factor (commercial success). In another case[citation needed] [], the Supreme Court also cautioned about using commercial success as an indicator of non-obviousness since the success may be attributed to external factors.

During this period, other courts have considered additional secondary considerations as well. See Environmental Designs, Ltd. v. Union Oil Co. of Cal., 713 F.2d 693, 697-98, 218 USPQ 865, 869 (Fed. Cir. 1983) (considering skepticism or disbelief before the invention as an indicator of non-obviousness); Allen Archery, Inc. v. Browning Mfg. Co., 819 F.2d 1087, 1092, 2 USPQ2d 1490, 1493 (Fed. Cir. 1987) (considering copying, praise, unexpected results, and industry acceptance as indicators of non-obviousness); Diversitech Corp. v. Century Steps, Inc., 850 F.2d 675, 679, 7 USPQ2d 1315, 1319 (Fed. Cir. 1988) (considering copying as an indicator of non-obviousness).

1984-2006: Teaching-suggestion-motivation test[edit]

At the same time the newly established United States Court of Appeals for the Federal Circuit, which was supposed to establish a uniform case law for patent validity appeals, started to reject the "unusual and surprising approach" altogether and introduced the "teaching, suggestion and motivation" (TSM) test in ACS Hosp. Sys. (1984)[citation needed]. The test allowed the rejection of a patent for obviousness only when factual teaching, suggestion or motivation from the prior art show the propriety of the patented combination.

Further, the combination of previously known elements can be considered obvious. As the Federal Circuit asserted inWinner Int'l Royalty Corp. v. Wang,[13] there must be a suggestion or teaching in the prior art to combine elements shown in the prior art in order to find a patent obvious. Thus, in general the critical inquiry, the Federal Circuit maintained, is whether there is something in the prior art to suggest the desirability, and thus the obvious nature, of the combination of previously known elements.

This requirement is generally referred to as the "teaching-suggestion-motivation" (TSM) test and is said to serve to prevent against hindsight bias.[14] As almost all inventions are some combination of known elements, the TSM test requires a patent examiner (or accused infringer) to show that some suggestion or motivation exists to combine known elements to form a claimed invention. Some critics of the TSM test have claimed that the test requires evidence of an explicit teaching or suggestion to make a particular modification to the prior art, but the Federal circuit has made clear that the motivation may be implicit, and may be provided for example by an advantage resulting from the modification. In other words, an explicit prior art teaching or suggestion to make a particular modification is sufficient, but not required for a finding of obviousness.

The TSM test is actually more similar to the requirement for novelty than for non-obviousness. Despite an immediate and overwhelming uproar in the technical and legal communities criticizing TSM as being too low, the Congress did not act to overturn the TSM standard. However, its application was refined by the US Supreme Court in KSR v. Teleflex (2006).

See also[edit]


  1. ^ a b Barton, John H. (2003). "Non-Obviousness". IDEA 43 (3): 475–506. "Non-obviousness," or, as known in Europe, "inventive step" is one of four traditional (and widely accepted) requirements for the grant of a patent. 
  2. ^ Barton, John H. (2003)
  3. ^ Kiklis (2014). The Supreme Court on Patent Law. Aspen Publishers Online. pp. 6–12. ISBN 9781454847748. 
  4. ^ Barton, John H. (2003). "Non-Obviousness". IDEA 43 (3): 475–506. Only research beyond that done as part of normal product design and development should be rewarded with a patent. Routine redesign should not be enough, for there is no need for monopolies as an incentive for such research. 
  5. ^ "Patent Act (R.S.C., 1985, c. P-4)". s.42. 
  6. ^ Windsurfing International Inc. v. Tabur Marine (Great Britain) Ltd., [1985] RPC 59 (CA).
  7. ^ Pozzoli Spa v BDMO SA & Anor (2007) EWCA Civ 588 (22 June 2007)
  8. ^ See Graham v. John Deere Co., 383 U.S. 1, 10 n.3 (1966) ("[A] change of material should not give title to a patent. As the making a ploughshare of cast, rather than of wrought, iron; a comb of iron, instead of horn or of ivory. . . ."
  9. ^ Ch.III
  10. ^ Merges and Duffy, ISBN 978-1-4224-8030-4 p.671
  11. ^ 340 U.S. at 152-53; Duffy p. 671.
  12. ^ 383 U.S. 1 (1966).
  13. ^ 202 F.3d. 1340, 1348 (Fed. Cir. 2000).
  14. ^ See In re Kahn,[citation needed] (Fed. Cir. 2006).

Further reading[edit]

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