optimization Archives - ElementIP Law

In Ex parte Abbott (Appeal No. 2021-000770), the examiner rejected the claims as obvious based on an optimization rationale. The PTAB reversed.

Independent claim 1 recited a lighting device for an additive manufacturing machine (i.e., a 3D printer). The device included an array of light sources configured to emit monochromatic light within a band of wavelengths. The band of wavelengths included a peak light absorption of a liquid coalescing agent, so that when the liquid coalescing agent absorbed the light, heat would be generated to melt or sinter a patterned building material.

Claim 1 recited a spectral intensity of at least 1 x 10¹² W m^-3 sr^-1 for each of the monochromatic light sources. The dispositive issue on appeal was whether this limitation was suggested by the applied references.

The examiner acknowledged that the primary reference (Miller) did not disclose this limitation. However, the examiner cited Miller’s teaching that the “amount of radiation provided to each location on the built model should be the amount that ensures sufficient curing in that location,” and that “[t]he radiation may be of any type, or in any wavelength that causes curing of the build material.” The examiner found that a skilled artisan “would have recognized that the light sources taught by Miller could be operated to emit a desired spectral intensity.” The examiner concluded that the claimed spectral intensity could be obtained through “routine optimization of this result-effective variable to provide the intended result of curing of build material during an additive manufacturing process.”

In contrast, the applicant noted that the Miller reference taught no specific values or ranges for spectral intensity. Because of this, the applicant argued that an optimization rationale was unsupported. The applicant cautioned that if the examiner’s position were correct, then the general disclosure of Miller would be sufficient to “render obvious the use of radiation to solidify anything under any conditions for every 3D printing process no matter how specific and how novel the radiation and no matter how different the process.”

The PTAB agreed with the applicant. The PTAB found the lack of any disclosed range of spectral intensity in Miller to be “akin to a very broad range (as there is not a set limit since no limit is provided in Miller).” The PTAB found such a broad range to be “so broad that there is no invitation for routine optimization.” Accordingly, the PTAB reversed the obviousness rejection.

Takeaway: Whenever an examiner takes the position that a claimed variable is a result-effective variable that would have been obvious to optimize, it is important to carefully evaluate the teaching of the prior art relating to the claimed variable. If, as in Ex parte Abbott, there are no specific values or ranges of the claimed variable in the prior art, then the optimization rationale might lack adequate support.

Judges: Franklin, Praiss, Inglese

In Ex parte Kano (Appeal No. 2021-004640), the Patent Trial and Appeal Board (“Board”) rejected an Examiner’s finding of obviousness that was premised on a nonoverlapping range being “sufficiently close.”

The independent claim on appeal was directed to a non-oriented steel having a chemical composition defined by various ranges of elements (e.g., C, Si, Mn, Al, P, S, N, etc.) and exhibiting, among other things, an X-ray diffraction (XRD) intensity ratio, I{100}/I{111}, between 0.50 and 1.18.

The primary reference relied on by the Examiner disclosed a non-oriented electrical steel sheet having a chemical composition that included each of the chemical elements in overlapping amounts, but failed to describe the intensity ratio. To remedy this deficiency, the Examiner relied on a secondary reference; however, its intensity ratio was greater than or equal to 1.20.

Notwithstanding the absence of an overlapping intensity ratio, the Examiner maintained obviousness on the basis that a steel sheet constructed from the prior art with an intensity ratio of 1.20 was sufficiently close to the claimed 1.18 ratio that one of ordinary skill in the art would expect them to have the same properties. The Board did not agree.

In particular, the applicant’s specification showed that the claimed intensity ratio resulted from a combination of the claimed composition and holding the composition at 550–700°C for 10–300 seconds (an intermediate holding step). The primary and secondary references relied on by the Examiner performed annealing processes at 950°C and 860°C, respectively, but did not include an intermediate holding step. Thus, the Board held that a skilled artisan would not have expected the steel composition from the Examiner’s hypothetical construct to have an intensity ratio within the claimed range and reversed the Examiner’s rejection.

Takeaway: While a prima facie case of obviousness may be established where the claimed range and the prior art range do not overlap, it is essential that there be an expectation that the properties would be the same. This expectation may be rebutted by information in the applicant’s own specification as in Kano or with additional experimental evidence. Another great source of rebuttal evidence is the prior art itself because a lot of times the prior art will associate its nonoverlapping range with a particular property and describe values outside that range (likely values within the claimed range) as inferior or different in some way such that a skilled artisan would not expect the properties to be the same.

Judges: J. Housel, W. Wilson, J. Gupta

In Ex parte Zhang (Appeal No. 2021-005022), the Patent Trial and Appeal Board (“Board”) rejected an Examiner’s finding of obviousness that was premised on an unappreciated ratio being a result-effective variable.

The independent claim on appeal read:

1. A sinterable conductive composition comprising:

a metal component having an average particle diameter of greater than about 150 nm to about 100 μm…;

a sintering agent; and

an emulsion comprising water, and

at least one particulate polymer having an average particle diameter

wherein a ratio of average metal component particle diameter to average particulate polymer particle diameter is between 1:1 and 10:1.

The Examiner rejected claim 1 over a primary reference that disclosed a metal component having an overlapping average particle diameter and a secondary reference disclosing metal particles, a sintering promoter, and an emulsion containing resin fine particles. Equating “fine particles” with nano-sized particles, the Examiner found the claimed ratio obvious (i.e., using the overlapping metal component diameter from the primary reference and the nano-sized particulate polymer diameter from the secondary reference).

In the alternative, the Examiner argued it would have been obvious to optimize the “fine particle” size to sufficiently disperse the polymer particles in the emulsion.

The Board rejected both of the Examiner’s positions. The Board first emphasized that claim 1 required a specific ratio particle size of the metal component and the polymer particle, and “not merely a size range for the polymer particle.” The primary reference did not disclose a particulate polymer so it could not possibly recognize a relationship between the metal component and the polymer particle.

As for the secondary reference, the diameter of the polymer relied on by the Examiner was for a precursor – not the final product – and nowhere did it suggest a relationship between the polymer particle size and metal particle size.

In the Board’s own words:

Missing from the record is any evidence of an interdependent relationship between the diameter sizes of the metal component and the polymer particle. In addition, nothing in the combined references suggests or recognizes that the claimed ratio relationship is a result effective variable.

…

We cannot accept general conclusions about what is ‘basic knowledge’ or ‘common sense’ as a replacement for documentary evidence for core factual findings in a determination of patentability.

Takeaway: Sometimes patentability resides in a relationship between properties that are seemingly obvious when considered individually. As shown in In re Zhang, when a reference relied on by the Examiner is missing the claimed property, it cannot possibly recognize a relationship involving that property. And even where a reference has the individual properties needed to arrive at the claimed relationship, the relationship will not obvious unless there is an overlap or a recognition of an interdependent relationship between the properties involved in the relationship.

Judges: C. Timm, D. Dennett, M. Cashion, Jr.

Ratios can be useful when claiming a subset of two well-known components or variables, particularly when the subset (defined by a ratio) provides a new and useful result. However, when the prior art teaches broad ranges for the individual components or variables, it is common for examiners and petitioners to argue obviousness based on overlapping theoretical ranges of the ratio derived from selecting the maximum and/or minimum values for each of the components or variables. The issue with this is approach is that the prior art may not direct a person of ordinary skill in the art (POSA) to the particular selections required to arrive at the claimed ratio. SNF S.A. v. Solenis Technologies is illustrative. IPR2020-01730, Paper 10 at 4 (PTAB April 22, 2021).

In SNF S.A., the challenged claims required a glyoxalated copolymer (G-PAM) obtained by reacting:

[A] 5–40 parts of glyoxal; and

[B] 60–95 parts of a cationic copolymer including:

[b1] ~15–85 wt% of diallyldimethylammonium halide monomer (DADMAC); and

[b2] ~85–15 wt% of acrylamide monomer,

the cationic copolymer having a weight average molecular weight (WAMW) of 120,000 to 1,000,000 Daltons, and

a ratio of the WAMW to the weight % of the DADMAC being greater than 4000 Daltons/weight%.

According to the background of the patent, the patentee found that the ranges of the WAMW and % DADMAC in combination with the claimed ratio thereof improved water drainage during processing and increased the strength of paper or boards treated with the G-PAM.

The petitioner, SNF S.A., argued obviousness based on three different primary references: Wright, Lu, and Dauplaise. The petitioner admitted that none of the cited references disclosed a ratio between WAMW and % DADMAC. To remedy this deficiency, the petitioner presented two arguments.

The petitioner’s first argument was that a POSA would have selected values of the WAMW and % DADMAC disclosed by each of the references to arrive at the ratio required by the claims. Specifically, with respect to the Wright reference, the petitioner argued “the ratio of 150,000 WAMW to 25 wt.% DADMAC, as both taught by Wright ’343, is 6,000 [and] … the ratio of 1,000,000 WAMW to 30 wt.% DADMAC is 33,333.” The petitioner supported this assertion with an expert declaration that similarly stated it would have been “obvious” and “routine” to select molecular weights of 150,000 (an upper endpoint of the preferred range) and to select DADMAC concentrations of 25% and 30% (preferred concentrations).

For ease of discussion, the scope covered by the claims (shaded blue box) relative to the scope disclosed by the Wright reference (shaded red box) and the two particular data points of the Wright reference relied on by the petitioner (red dots) are shown graphically below and here:

As shown above, Wright’s broad WAMW range of 30,000 to 5,000,000 and broad % DADMAC range of 0.1–90 wt% cover a WAMW/%DADMAC ratio of 4,000, as they theoretically cover ratios from 333 to 5×10⁷. And although one of the ratios derived by the petitioner (lower red dot) was derived from a preferred amount of DADMAC (25 wt%) and an upper endpoint of a preferred WAMW range (150,000), the Board found:

Petitioner, however, never explains how or why a person of ordinary skill in the art would have been led to select the value ‘150,000 WAMW,’ or ‘25 wt.% DADMAC,’ or any of the specific values it uses to calculate the claimed ratio. Nor does Petitioner direct us to any disclosure in the prior art showing an embodiment having the specific values used in Petitioner’s calculations.

…

Absent explanation from Petitioner, it appears that Petitioner picked the specific values it used to calculate a ratio from broad, unrelated ranges of WAMW and % DADMAC disclosed in the prior art simply because they combine to produce a ratio that meets the ratio recited in the claims of the ’320 patent. This suggests Petitioner relied on hindsight in forming its challenges. Metalcraft of Mayville, Inc. v. The Toro Co., 848 F.3d 1358, 1367 (Fed. Cir. 2017) (‘[W]e cannot allow hindsight bias to be the thread that stitches together prior art patches into something that is the claimed invention.’).

This use of hindsight is not excused by the mere fact that the specific values combined to produce the claimed ratio fall within the ranges disclosed in the prior art.

The other two primary references relied on by the petitioner, Lu, and Dauplaise, suffered similar defects.

The petitioner’s second argument was that “a POSA would have arrived at the ratio using routine experimentation to optimize result-effective variables, as guided by the art.” The Board also rejected this argument.

First, the Board found that a POSA would not have optimized the ratio itself because “there is no evidence that skilled artisans knew that the claimed ratio of WAMW to % DADMAC was a parameter of any importance or one worth optimizing.” That is, the ratio was not a result-effective variable.

Second, the Board found that there was no persuasive evidence to support a conclusion that independently optimizing WAMW and % DADMAC would result in a polymer having the claimed ratio rather than one of the many ratios falling outside the scope of the claims. Again, the Board emphasized the innumerable combinations of values. But it seemed that the Board was more persuaded by the fact that there was evidence of polymers outside the scope of the claim exhibiting the same properties as those having the claimed ratio such that optimization could equally result in a copolymer having a ratio outside the claim. Ultimately, the Board concluded that the evidence did not support the petitioner’s assertion that independent optimization would lead to the claimed ratio.

For the foregoing reasons, the Board concluded that the petitioner failed to carry its burden and declined to institute the IPR.

Takeaway: When facing an office action or post-grant petition in which a claimed ratio is alleged to be obvious based on the selection or optimization of the components making up the numerator and denominator, you should first determine whether the ratio itself is a result-effective variable. If not, the next step is to determine whether there is an embodiment that discloses values for the numerator and denominator that would result in the claimed ratio. As shown in SNF S.A., the fact that specific values can be combined to produce the claimed ratio is insufficient by itself when there are innumerable combinations of values. If neither of these applies, the final step is to determine whether the prior art teaches a reason to optimize the numerator and denominator in a manner that would result in the claimed ratio.

Judges: C. Crumbley, J. Abraham, D. Cotta

Ex parte Yim, is a recent decision of the Patent Trial and Appeal Board (PTAB) addressing whether claimed properties were inherent in prior art compositions.

In Ex parte Yim, the claim at issue was directed to a resin. However, the resin was not defined by structure or composition. Instead, only properties of the resin were recited in the claim: (a) content of water-soluble fraction, (b) absorbency against pressure property, and (c) water-soluble fraction shear index property. Independent claim 16 is reproduced in part below:

16. A water-absorbing resin, in which

[a] a content of a water-soluble fraction is 15 wt% or less based on the total weight of the resin,

[b] an absorbency against pressure at 0.3 psi with respect to a saline solution including sodium chloride at 0.9 wt% is 25 g/g or more, and

[c] a water-soluble fraction shear index A/B represented by the following Expression 1 is in a range of 0.1 x 10^-5 (s) to 10 x 10^-5 (s)….

In rejecting the claim, the examiner relied on a single prior art reference that disclosed a water-absorbing resin but did not disclose the properties recited in the claim. Both the prior art reference and the application on appeal disclosed forming water-absorbing polymers by polymerizing and crosslinking an acrylic acid monomer. The examiner asserted that, in view of the similarities in starting materials and processing steps used in the prior art reference and the application on appeal, the properties in the claim were inherent in the water-soluble resins of the prior art reference.

The examiner further asserted that, even if applicant could demonstrate that none of the water-soluble resins exemplified in the prior art reference had the claimed properties, it would have been obvious to tune the reactions in the prior art references to optimize absorbance/solubility characteristics.

The examiner’s inherency arguments turned, particularly, on the examiner’s determination that the prior art reference used two internal crosslinkers to crosslink an acrylic acid, which was the same or similar to the method disclosed in the application on appeal. Applicant countered by arguing, inter alia, that the steps of the prior art method were different such that the two internal crosslinkers were reacted together before being added to acrylic acid, which could not be said to necessarily result in the claimed properties.

The PTAB found that the examiner had made a good argument that the processes of the prior art reference would result in the claimed properties, such that it became applicant’s burden to show that the exemplified resins did not possess the claimed properties. The PTAB also noted that applicant failed to present arguments rebutting the examiner’s fallback assertion that optimizing the properties of the prior art resin would have been a mere matter of routine experimentation to a skilled artisan. Thus, the examiner’s rejection was affirmed.

Takeaway: Parameter or property claims can be valuable in a patent directed to a material or chemical composition. By keeping strict compositional or structural limitations out of a claim, materials or compositions not contemplated at the time of filing may be encompassed by the claim. Further, if claimed parameters/properties are not explicitly disclosed in the prior art, it can be difficult for a third party to confidently analyze the validity of the claim. However, these advantages in a patent claim can be challenges during examination. While some parameter/property claims “sail through” examination, Ex parte Yim shows that an applicant should be prepared to reproduce prior art examples and provide evidence to rebut assertions of routine optimization to obtain allowance.

Judges: Timm, Smith, Range

Ex parte Whalen, is a 2008 decision of the Board of Patent Appeals and Interferences (BPAI) that is listed among the Patent Trial and Appeal Board’s (PTAB) precedential decisions. Ex parte Whalen, is indicated by the PTAB to be precedential as to “Anticipation – 35 U.S.C. § 102… Inherency… evidence and reasoning” and “Obviousness – 35 U.S.C. § 103… Rationales… optimizing a variable.”

According to the PTAB’s Standard Operating Procedure, “[a] precedential decision is binding Board authority in subsequent matter involving similar facts or issues.”

In Ex parte Whalen, the BPAI considered whether an examiner met his burden in asserting inherency, or alternatively routine optimization, of a claimed viscosity that was not explicitly disclosed in the prior art.

Independent claim 1 was identified as a representative claim:

A composition capable of embolizing an aneurysm at a vascular site comprising:

(a) a biocompatible polymer;

(b) a biocompatible contrast agent wherein a sufficient amount of said contrast agent is employed in said composition to effect visualization in vivo; and

(c) a biocompatible solvent which solubilizes said biocompatible polymer

wherein a sufficient amount of said polymer are [sic] employed in said composition such that, upon delivery to a vascular site, a polymer precipitate forms which embolizes said vascular site; and

further wherein the biocompatible polymer has a molecular weight sufficient to impart to the composition a viscosity of at least about 150 cSt at 40° C.

The claim was rejected as anticipated or obvious over several prior art references. All of the cited prior art references disclosed combinations of components (a), (b), and (c) in compositions for embolizing an aneurysm at a vascular site, but none explicitly disclosed a composition having “a molecular weight sufficient to impart to the composition a viscosity of at least about 150 cSt at 40° C.” The examiner argued that the prior art compositions inherently possessed the claimed viscosity or, alternatively, it would have been obvious to a skilled artisan to “optimize” the prior art compositions by increasing their viscosity to the level recited in the claims.

It was undisputed that the prior art disclosed compositions including components (a), (b), and (c) in amounts overlapping those in the specification and claims of the application on appeal. However, the only disclosure in the prior art of viscosity was of a preferred composition having a viscosity much lower than the viscosity specified in claim 1. The BPAI found that the examiner had not met his burden in establishing inherency. The BPAI stated that, even if some of the compositions encompassed by the prior art’s broad disclosure might have the claimed viscosity, “that possibility is not adequate to support a finding of inherent anticipation.” The BPAI noted that the examiner did not provide evidence or scientific reasoning to show that any specific composition disclosed in the prior art was within the scope of claim 1.

The examiner’s obviousness position rested on the assertion that a skilled artisan would have been motivated to optimize the viscosity of the prior art composition to achieve “the safest clinical outcome and avoiding transvenous passage.” The BPAI noted that the prior art disclosed “adjustment of the viscosity of the composition as necessary for catheter delivery can be readily achieved by mere adjustment of the molecular weight of the copolymer composition.” However, the prior art also disclosed that low viscosity was a desired property in embolic compositions and, as noted above, the only disclosed viscosity in the prior art was much lower than that of claim 1.

Taking the foregoing facts into consideration, and mindful of the Supreme Court’s (then) recent command of “flexibility” in the obviousness inquiry (KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398 (2007)), the BPAI nonetheless concluded that the examiner had not met his burden. Particularly:

… when the prior art teaches away from the claimed solution as presented here… obviousness cannot be proven merely by showing that a known composition could have been modified by routine experimentation or solely on the expectation of success; it must be shown that those of ordinary skill in the art would have had some apparent reason to modify the known composition in a way that would result in the claimed composition.

That is, the examiner was required but failed to provide an “explanation based on scientific reasoning” that would support the conclusion that a skilled artisan would have considered it obvious to optimize the prior art compositions by increasing their viscosity to the level recited in the claims.

Ex parte Whalen was decided by an expanded five-judge panel, instead of the usual three-judge panel. The Chief Administrative Patent Judge was one of the deciding judges. According to the PTAB’s Standard Operating Procedure, “[a]n expanded panel is not favored and ordinarily will not be used… [a]n expanded panel may be used, where appropriate, to secure and maintain uniformity of the Board’s decisions…”

Takeaway: One of the challenges of prosecuting composition claims (combinations of known components) is the seeming ease with which an examiner can assert that a property not explicitly disclosed in the prior art is inherent and/or would have been readily achieved by a skilled artisan as a matter of routine optimization. Of course, the burden-shifting framework for examination of claims reciting properties is reasonable; however, there remains some burden on the examiner. Rejections based on inherency or routine optimization require that the examiner provide “scientific reasoning” consistent with the overall teaching of the prior art. Conclusory or thinly reasoned assertions of inherency or routine optimization thus provide an avenue for challenge.

Judges: Fleming, Lane, Grimes, Lebovitz, Prats

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PTAB Tosses Examiner’s Result Effective Variable Rationale For Unappreciated Ratio

Nonobvious Ratio From Obvious Numerator and Denominator

Parameter/Property Claims Can Be Valuable In Patents But Challenging During Examination

Examiner Burden in Showing Inherency and Routine Optimization – Past “Precedential” PTAB Decisions

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