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October 4, 2022by Matthew Barnet

In Ex parte Makarova (Appeal No. 2022-002730), the examiner rejected the claims as obvious based on a combination of references. The PTAB reversed, finding important differences between two references suggesting they should not be combined in the way proposed by the examiner.

Independent claim 1 recited:

A microfilter comprising:

a single polymer layer formed from an epoxy-based negative photo-definable dry film, wherein the single polymer layer has a flexibility to be disposed on a roll and unrolled; and

a plurality of apertures formed by exposing the single polymer layer to a UV light via an optical mask to obtain a selected shape of said apertures based on said mask, each of said apertures extending through the single polymer layer having said flexibility,

said single polymer layer having said flexibility forming a freestanding unattached microfilter structure with uniform thickness and having said flexibility.

The examiner found that the primary reference (Wolfe) described most of the limitations of claim 1. For example, Wolfe described a particulate filter with regularly spaced micropores, which comprised a single flexible polymer layer formed from a photo-definable dry film (MYLAR). The single polymer layer in Wolfe had flexibility sufficient to be disposed on a roll and unrolled, and its apertures were formed by exposing the single polymer layer to radiation via an optical mask. The single polymer layer also formed a freestanding, unattached microfilter structure with a uniform thickness.

However, the film in Wolfe was not an epoxy-based film, as recited in claim 1. The examiner turned to a secondary reference (DuPont) for this limitation.

The examiner found that DuPont described a flexible epoxy-based negative photo-definable dry film that had excellent thickness uniformity after hot roll lamination. The examiner found that it would have been obvious to substitute the film from DuPont into Wolfe’s system because both references related to microfabricated polymer membrane structures.

The applicant argued that such a substitution would not have been obvious. In particular, the applicant noted that DuPont’s film was “best suited for permanent applications where it is imaged, cured and left on devices” rather than being a freestanding unattached structure as recited in claim 1. Additionally, the excellent thickness uniformity after hot roll lamination in DuPont was premised on the film being laminated to a substrate, rather than being freestanding.

The PTAB sided with the applicant. The PTAB found that “because DuPont specifically indicates that its film is best used while laminated to an underlying substrate, a person of skill in the art would not have thought that film to be a substitute for Wolfe’s freestanding polymeric sheet.” The PTAB concluded that “the Examiner’s rationale as to why a person of skill in the art would have substituted DuPont’s film for Wolfe’s polymeric sheet is not adequately supported by the evidence of record.” Accordingly, the PTAB reversed the obviousness rejection.

Takeaway: Obviousness rejections often involve a primary reference describing most of the claimed elements, with a secondary reference used to fill in gaps in the primary reference. When an examiner takes the position that it would have been obvious to substitute an element from the primary reference with an element from the secondary reference, it is worth challenging that position if there is a good reason not to make such a substitution.

Judges: Housel, Best, Wilson


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August 5, 2022by Matthew Barnet

In Ex parte Whiteman (Appeal No. 2021-003736), the examiner rejected the claims as obvious based on a hypothetical particle distribution consistent with the prior art. The PTAB reversed.

Independent claim 1 recited:

An inorganic particulate material comprising:

equal to or more than about 3 ppm of particles having a particle size equal to or greater than about 25 μm,

equal to or less than about 40 wt% of particles smaller than about 0.75 μm,

having a d98 less than about 11 μm, and

wherein the % of particles smaller than 0.5 μm is equal to or less than about 25 wt%.

Relevant to the appeal, the italicized limitations required that (i) particles smaller than about 0.75 μm made up no more than about 40 wt% of the particle distribution, and (ii) particles smaller than 0.5 μm made up no more than about 25 wt% of the particle distribution. In other words, there could not be a large fraction of very small particles. For example, a distribution in which 50 wt% of particles were smaller than 0.75 μm would be outside the scope of the claims, as would a distribution in which 30 wt% of particles were smaller than 0.5 μm.

The examiner rejected claim 1 as obvious over a single reference (Calhoun). The examiner relied on a d50 value (rather than wt%) in the range of 0.8 to 3 μm in Calhoun. A d50 value of 0.8 μm, for example, would mean that 50% of the particles were smaller than 0.8 μm. The examiner took the position that the d50 value in Calhoun “impl[ied] or at least suggest[ed] that the claimed wt% of <~0.75μm particles is met.” The examiner found that it would have been obvious “to adjust the particles’ size (either by removing undesirably-sized particles and/or agglomerates, grinding too large particles/agglomerates, and/or agglomerating too small particles)…to meet the claimed wt% of <~0.75μm particles.”

The applicant argued that although Calhoun described a d50 value in the range of 0.8 to 3 μm, the reference said nothing about the fraction of particles smaller than 0.75 μm, or smaller than 0.5 μm, as recited in claim 1. The applicant argued that the examiner had created “a convoluted hypothetical” particle distribution from Calhoun, in which a d50 value of 0.8 μm could be satisfied by 40 wt% of the particles being smaller than 0.75 μm (according to claim 1), and 10 wt% of the particles being between 0.75 and 0.80 μm. Although such a hypothetical particle distribution might have been consistent with the d50 value in Calhoun, the applicant argued that this hypothetical particle distribution was in no way disclosed or suggested by Calhoun.

The PTAB sided with the applicant. The PTAB found that Calhoun’s d50 value of 0.8 to 3 μm “neither discloses nor suggests anything about the particular percentage of particles smaller than about 0.75 μm or smaller than 0.5 μm.” The PTAB found that the “[e]xaminer assumes without providing sufficient evidence that Calhoun’s preferred particulate product having a d50 of 0.8-3 μm contains ‘smaller portion[s] within’ the product, which meet the claimed particular product size distributions.” Accordingly, the PTAB reversed the obviousness rejection.

Takeaway: Obviousness cannot be based on speculation. If a U.S. examiner finds a claimed feature to be obvious over prior art describing a somewhat related, but different feature, the examiner must provide supporting evidence instead of mere speculation. If, as in Ex parte Whiteman, the examiner speculates about a “convoluted hypothetical” feature that is consistent with the prior art – but is not disclosed or suggested by the prior art – it is worth challenging the examiner’s position.

Judges: Colaianni, Dennett, McGee


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June 27, 2022by Matthew Barnet

In Ex parte Jung (Appeal No. 2021-003163), the examiner rejected the claims as obvious based on an inherency rationale. The PTAB reversed.

Independent claim 16 recited an inkjet set consisting of:

a black inkjet ink, a cyan inkjet ink, and two inkjet inks A and B… wherein

the inkjet ink A has a hue angle H* between 70 and 85 and a chroma C* between 30 and 80;

the inkjet ink B has a hue angle H* between 20 and 40 and a chroma C* between 30 and 80 …

The dispositive issue on appeal was whether the hue angle H* and chroma C* were inherent in the applied art.

The examiner cited a reference broadly disclosing mixtures of pigments, and including the specific pigments C.I. Pigment Orange 71, C.I. Pigment Yellow 139, C.I. Pigment Red 254, and C.I. Pigment Red 122 among a long list of suitable pigments. The examiner noted that these specific pigments were recited in the applicant’s dependent claims 19 and 21. Based on this, the examiner took the position that if these specific pigments were selected in the reference, the resulting inks “would intrinsically [i.e., inherently] have” the claimed H* and C* values.

The applicant argued that even if the specific pigments were selected in the reference, the claimed H* and C* values would not necessarily result. The applicant stated that these limitations “are not only achieved by selecting specific pigments, but also by the amounts of the pigments used and the weight ratio of the different pigments in the mixture.” Additionally, the applicant provided calculations of H* and C* values resulting from the examples of the reference, showing them to fall outside the claimed ranges. However, the examiner dismissed these calculations as “attorney argument and not evidence.”

The PTAB sided with the applicant. The PTAB found that “the use of the recited pigments alone is not adequate to guarantee that the H* and C* limitations are met” and that the ratio of different pigments mattered. Regarding the calculations provided by the applicant, the PTAB found that the examiner dismissed them in error (“There is no dispute that the calculations are based on examples disclosed by [the reference], and there is no dispute as to the accuracy of the calculations. Because [the reference] itself is evidence, the calculations made using the data from [its] examples should not have been disregarded as mere ‘attorney arguments.’”).

The PTAB acknowledged that the claims still might have been obvious if the reference “teaches or suggests combining pigments in a way (e.g., optimizing the weight ratios of different pigments) that would have resulted in H* and C* values within the scope of claim 16.” However, the PTAB found no such teaching or suggestion. While the reference taught that the pigments or mixture of pigments be present “in an amount of 0.1 to 20% by weight based on the total weight of the non-aqueous inkjet ink,” the reference provided no teaching or suggestion for weight ratios among different pigments. Accordingly, the PTAB reversed the obviousness rejection.

Takeaway: Whenever an examiner takes the position that a claimed property is inherent in the applied art, it is important to carefully evaluate embodiments of the applied art that might result in the claimed property. Inherency requires necessity, not merely possibility. That is, just because it might be possible for the applied art to satisfy a claimed property, that does not mean that the applied art necessarily satisfies the property. If the prior art does not necessarily satisfy the claimed property, then inherency has not been established.

Judges: Abraham, Kennedy, Gupta


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May 13, 2022by Matthew Barnet

Composition claims sometimes recite a ratio of amounts of two different components in the composition. Similarly, claims relating to a polymeric compound sometimes recite a ratio between two different structural units of the compound. In evaluating obviousness, U.S. examiners search the prior art for ratios that overlap the claimed ratio. Ex parte Kraus (Appeal No. 2021-002347) is a recent decision of the Patent Trial and Appeal Board (“Board”) in which the examiner went a little too far in trying to find such a ratio in the prior art.

Independent claim 1 related to a polycondensate comprising at least four different structural units: (I), (IIa), (IIb) and (III). Among other limitations, the claim recited a molar ratio of structural unit (IIa) to (IIb) within the range of 0.2 to 1.5.

The examiner rejected claim 1 as obvious over one reference (Wieland), and separately over a different reference (Kraus). In the rejection based on Wieland, the examiner relied on a ratio that included structural units corresponding to (IIa) and (IIb). However, the examiner acknowledged that this was not exactly a ratio of (IIa) to (IIb) since the structural units of Wieland corresponding to (IIa) and (IIb) both were encompassed by the denominator of Wieland’s disclosed ratio. The examiner also relied on values derived from two specific examples in Wieland to construct a ratio of (IIa) to (IIb) overlapping the claimed range.

The Board reversed the rejection over Wieland. The Board found that “[t]he Examiner has not explained sufficiently why one of ordinary skill in the art would mix and match molar concentration values from two different examples to determine a ratio of (IIa) to (IIb) as claimed, particularly given that Wieland’s ratio is different.” The examiner’s calculation “involves picking and choosing convenient values from two unrelated examples to calculate a ratio not used by Wieland.”

In the rejection based on Kraus, the examiner combined a disclosed ratio of structural unit (I) to (IIa) with a disclosed ratio of the sum of structural units (I) and (IIa) to structural unit (IIb). The examiner found that this combination supported a range of molar ratios (IIa) to (IIb) that overlapped the claimed range of 0.2 to 1.5.

The Board also reversed this rejection. The Board found that the examiner had not adequately explained how the two disclosed ratios could be combined to obtain the claimed ratio. The Board noted that “[t]he calculation posited by the Examiner apparently requires substitution of a range within another range,” which it found not to be obvious.

Takeaway: A ratio between two components in a composition, or two structural units in a polymeric compound, can be a useful way to distinguish a claimed invention from prior art. If an examiner appears to be stretching the prior art to construct an overlapping ratio, it is worth challenging the examiner’s rationale.

Judges: Hastings, Kennedy, Cashion Jr.


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April 7, 2022by Matthew Barnet

U.S. patent claims typically use the terms “comprising” and “consisting of” when reciting components of a composition. “Comprising” indicates that the composition must include the recited components, but also can include unrecited components, while “consisting of” indicates that the composition excludes unrecited components.

The term “comprising” advantageously provides the applicant with broader scope of protection than “consisting of.” However, such breadth sometimes opens claims to additional prior art. In such cases, “consisting of” can be helpful to distinguish the claims from the prior art.

When claims use both “comprising” and “consisting of,” the scope of the claims must be analyzed carefully. This issue is illustrated in the recent case of Ex parte Rankin (Appeal No. 2021-001726).

Independent claim 40 recited (in part) a composition comprising:

(i) a gel base consisting of:

a wax or oil and;

a salt; and

(ii) titanium dioxide, zinc oxide, barium sulfate, or a combination thereof dispersed in the gel base.

The examiner rejected claim 40 as anticipated by two different references disclosing gels containing titanium dioxide. The gels also included polymeric gelling agents. In each case, the examiner took the position that the gelling agent was within the scope of the claim based on the open “comprising” term in the preamble. For example, in one anticipation rejection, the examiner stated that claim 40 “is interpreted to mean that the gel base consists of a wax or oil, and a salt, but it does not exclude addition of other components, such as the block polymers taught by [the cited reference] to make the final…product.”

In contrast, the applicant argued that the closed “consisting of” term excluded the polymeric gelling agents of the prior art. For example, the applicant alleged that the gels of the cited reference “differ structurally from the gel of claims 40-55 due to the latter being composed exclusively of a wax or oil and salt and therefore excluding the polymers…as constituent structural components.”

The PTAB agreed with the applicant. The PTAB acknowledged that “the ‘comprising’ language in the claim allows the mixture of the gel base and titanium dioxide, zinc oxide, barium sulfate or combination to include additional components dispersed in the gel base.” However, due to the “consisting of” language, “the gel base may contain only the recited wax or oil and salt…[W]e do not agree [with the examiner] that the claim language allows for the addition of ingredients to the gel base.” Accordingly, the PTAB reversed the anticipation rejections.

Takeaway: Whenever a claim uses both “comprising” and “consisting of,” the scope of the claim must be analyzed carefully. The closed, “consisting of” term might be intended to exclude a component disclosed in the prior art, but the examiner might take the position that the component is within the claim scope due to the “comprising” term. In such cases, it is important to clearly identify how the components of the prior art correspond to the claim. In Rankin, the applicant successfully argued that the polymeric gelling agent of the prior art was a component of the gel base (thus excluded by the “consisting of” term) rather than a component dispersed in the gel base (which would have been included by the “comprising” term).

Judges: Adams, Grimes, Jenks


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March 4, 2022by Matthew Barnet

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


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January 28, 2022by Matthew Barnet

In Ex parte Scheich (Appeal No. 2021-003495), the examiner rejected the claims as obvious over a combination of two references. The PTAB reversed.

Independent claim 1 recited:

A diffuser material of pore-containing quartz glass with

a chemical purity of at least 99.9% SiO2,

a cristobalite content of not more than 1%, and

a density in the range of 2.0 to 2.18 g/cm3,

whereby at least 80% of the pores have a maximum pore dimension of less than 20 μm,

wherein the quartz glass is produced synthetically,

has a hydroxyl group content in the range of more than 200 wt. ppm, and

contains hydrogen in a concentration in the range of 1017 molecules/cm3 to 1019 molecules/cm3.

The examiner found that the primary reference (Moritz) satisfied each limitation of claim 1, except for being silent about a hydrogen concentration. The examiner cited a secondary reference (Ohama) describing a similar quartz glass. The quartz glass in Ohama was made from a silica powder having a hydrogen concentration overlapping the range recited in claim 1.

The examiner took the position that it would have been obvious to use Ohama’s silica starting material to prepare the quartz glass of Moritz. The examiner found that the hydrogen concentration of the finished product would be expected to be the same as that of the starting material because “[n]o evidence is given” to the contrary, and “Ohama provides no teaching or suggestion that the hydrogen is removed from the powder prior to or during formation of the inventive quartz material.”

In contrast, the applicant argued that the finished product in Ohama would not be expected to have the same hydrogen content as the starting material. In particular, the applicant argued that the sintering process in Ohama would be expected to reduce or remove molecular hydrogen from the starting material in forming Ohama’s finished product. As evidence, the applicant cited a portion of Ohama describing that the hydrogen in the starting material “react[s] with free oxygen to form OH groups, and the OH groups are fixed in the glass to suppress pore expansion from occurring.”

The PTAB agreed with the applicant. The PTAB found that “Ohama discloses that the hydrogen in Ohama’s starting material reacts with oxygen in a way that would consume Ohama’s hydrogen, such that Ohama’s final quartz glass product would not have the same hydrogen concentration as its silica powder starting material.” In a footnote, the PTAB acknowledged that the broad range of hydrogen concentration in Ohama’s starting material might allow for significant removal of hydrogen while still satisfying the claimed range for the finished product. However, since the examiner made no findings as to an expected magnitude of the decrease of hydrogen, the PTAB reversed the obviousness rejection.

Takeaway: U.S. examiners often make inferences beyond the explicit teachings of prior art references. These inferences usually are phrased in terms of what would have been expected based on the technical knowledge of a person of ordinary skill in the art. Sometimes applicants can rebut such inferences with evidence of their own. This evidence can be provided in the form of a Rule 132 Declaration, or, as in Ex parte Scheich, by reference to portions of the applied art.

Judges: Best, Kennedy, Cashion Jr.


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December 22, 2021by Matthew Barnet

In Ex parte Ruvolo (Appeal No. 2021-001708), the examiner rejected nucleotide claims as anticipated under § 102. The PTAB reversed.

Independent claim 12 recited (in part):

A composition of matter comprising:

a first population of oligonucleotides comprising a top strand sequence having the following formula:

V1-B-3’; and

a second population of oligonucleotides comprising a bottom strand sequence having the following formula:

V2‘-B’-3’;…

Claim 12 further specified (in part) that (i) the nucleotide sequences of B and B’ are complementary and at least 15 nucleotides in length, (ii) the first and second population of oligonucleotides are capable of hybridizing to each other to produce a population of duplexes, and (iii) V1 and V2’ hybridize to different sites in a reference genome.

The examiner cited as anticipatory a reference (Koroulis) disclosing an oligonucleotide array. The reference included the general statement that the array could “contain all possible oligonucleotides of a given length n.” The examiner took the position that “[g]iven that the composition/array of Koroulis et al., encompasses all possible oligonucleotides of a length n, such must encompass the very oligonucleotides present in the claimed composition and kit, including that represented by the formulae of V1-B-3’; and V2‘-B’-3’.”

The appellant argued that the general statement in Koroulis was insufficient for anticipation, and that “[t]he Office Action makes no attempt to identify where Koroulis discloses the particular claim elements recited by the rejected claims.”

The PTAB sided with the appellant. It found that “[t]he bare statement that an array can include all possible nucleotides having an undefined length is not a disclosure of the two populations of oligonucleotides – having segments meeting specified structural requirements, arranged in a specified way – that are recited in Appellant’s claims.” Accordingly, the PTAB reversed the anticipation rejection.

The examiner also rejected the claims as patent ineligible under § 101, as allegedly directed to a natural phenomenon (“the claims are to oligonucleotides, the nucleotide sequence of which can occur in nature”). The PTAB also reversed this rejection, as a straightforward application of the U.S. Supreme Court’s Myriad decision.

In particular, the PTAB found the claimed oligonucleotides to be analogous to the cDNA found patent eligible in Myriad: “[t]he V1 and V2’ segments recited in Appellants’ claims might have the same sequence of nucleotides as found in a naturally occurring genome (since they hybridize to a reference genome) but the Examiner has not shown that a population of such segments – having variable sequences – are naturally found next to a common B or B’ sequence in their natural state.” Accordingly, the PTAB reversed the eligibility rejection.

Takeaway: Anticipation requires that a reference discloses “all of the limitations arranged or combined in the same way as recited in the claim.” Net MoneyIN, Inc. v. VeriSign, Inc., 545 F.3d 1359, 1371 (Fed. Cir. 2008). Ex parte Ruvolo shows that an overly general disclosure is insufficient to establish anticipation if the disclosure does not address specific limitations in the claims. By emphasizing the specific limitations in the claims, the Appellant in Ex parte Ruvolo overcame the anticipation rejection, as well as the § 101 rejection.

Judges: Grimes, Hulse, Townsend


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November 12, 2021by Matthew Barnet

During patent prosecution in the U.S., claims are given their broadest reasonable interpretation consistent with the specification. Ex parte Adel (Appeal No. 2020-006165) is a recent case in which the Patent Trial and Appeal Board (“Board”) found an examiner’s broad interpretation to be unreasonable.

Independent claim 1 recited (in part):

A process for manufacturing an edible water-in-oil emulsion, comprising the steps of:

a) providing a water-phase;

b) providing a liquid oil;

c) providing a fat powder comprising hardstock fat;

d) providing a hardstock fat in liquid form;

e) mixing the fat powder comprising hardstock fat, the hardstock fat in liquid form, and the liquid oil to form an oil-slurry, wherein the hardstock fat in liquid form is completely liquid before contact with the fat powder; …

The examiner rejected the claims as obvious over a combination of references. In the examiner’s proposed combination, the hardstock fat in liquid form included a portion that had crystallized (i.e., solidified) before contacting the fat powder.

The appellant argued that the existence of the crystallized portion meant that the hardstock fat in liquid form was not completely liquid before contact with the fat powder, contrary to the requirement of claim 1.

The examiner took the position that the hardstock fat containing the crystallized portion nonetheless satisfied the claim limitation of being “completely liquid.” The examiner noted that the primary reference described the hardstock fat as being “pumpable,” and stated that “[i]t is well understood that pumpable refers to the ability to move or transfer fluids or liquids.” The examiner took the position that the hardstock fat containing the crystallized portion “successfully meets the claimed limitation of the hardstock fat in liquid form [being] completely liquid.”

The Board disagreed with the examiner. The Board found it “unreasonable to interpret the term ‘completely liquid’ as encompassing hardstock fats that have already undergone some amount of crystallization. A liquid that has already undergone some amount of crystallization is not ‘completely’ liquid.” The Board found that such an “interpretation renders the word ‘completely’ a nullity, and such interpretations are disfavored.” Accordingly, the Board reversed the obviousness rejection.

Takeaway: U.S. examiners sometimes interpret the claims in a broader way than applicants intend. In such situations, it might be possible to argue that an examiner’s interpretation is unreasonably broad, and thus improper. Since examiners are likely to consider their interpretations to be reasonable, however, such arguments might require a supporting declaration from a skilled artisan, or an appeal to the PTAB.

Judges: Wilson, Kennedy, Gupta


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October 1, 2021by Matthew Barnet

Process (or method) claims recite one or more actions or steps to be performed. For example: a process for producing NaCl, comprising steps A, B and C. In contrast, product-by-process claims recite a product that is produced by a certain process. For example: NaCl, produced by a process comprising steps A, B and C.

In determining whether a process claim is obvious, a U.S. examiner compares the claimed process to the prior art, and asks whether the prior art suggests all the limitations (i.e., all actions or steps) recited in the process claim. In the example above, the examiner would assess the prior art for a suggestion of steps A, B and C.

The inquiry is somewhat different for a product-by-process claim. For infringement purposes, a product defined by a product-by-process claim is limited by the process. However, the patentability of the product does not depend on the process but on the product itself. In the example above (NaCl, produced by a process comprising steps A, B and C), the examiner would assess the prior art for a suggestion of the product (NaCl) not for a suggestion of the process (steps A, B and C). If the examiner could provide a rationale tending to show that the product appeared to be the same as or similar to that of the prior art, although produced by a different process, the burden would shift to the applicant to provide evidence establishing a nonobvious difference between the claimed product and the prior art product.

This important difference between process claims and product-by-process claims is illustrated in the recent Patent Trial and Appeal Board (“Board”) case of Ex parte Liu (Appeal No. 2020-006403).

Independent claim 1 recited:

A pot furnace low-temperature calcination method comprising:

providing a pot;

providing a flame path proximate to the pot such that heat from the flame path heats the pot;

controlling a flame path temperature and discharge rate of the pot furnace such that petroleum coke is calcined in the pot at a temperature range from 1150°C to 1220°C, the discharge rate of the pot being controlled to be 110 – 120 kg/hr; and

reducing an amount of desulfurization of the petroleum coke during calcination so that true density of the calcined coke is between 2.05 and 2.07 g/cm3;

wherein the flame path temperature is controlled to be less than 1250°C.

The examiner rejected claim 1 as obvious. In response, the applicant argued that the applied prior art did not suggest the process limitation of a discharge rate of 110 to 120 kg/hr. On appeal, the examiner seemed to apply a product-by-process interpretation to the claimed discharge rate: “It is not necessary for the reference to make or recognize the same mental correlation or relationship as appellant, nor to heat for the same reasons, as long as the product made is the same or essentially the same” (emphasis added).

The Board agreed with the applicant. The Board noted that “the claim is a method claim and not a product-by-process claim. Thus, it is the method step recitations that cannot be skipped in making an obviousness determination.” Accordingly, the Board reversed the obviousness rejection.

Takeaway: It is important to keep in mind the difference between process claims and product-by-process claims. If an examiner refuses to give patentable weight to a process limitation because he considers it to be a product-by-process limitation, this can form the basis of a successful appeal.

Judges: Franklin, Gupta, Inglese