Fifth in a series of articles aimed at scientists, engineers, business managers, non-patent lawyers, and other professionals that desire or need to understand basic principles of patent law and practice.

Be sure of it; give me the ocular proof.
– Shakespeare, Othello, III, iii, 361

The proof of the pudding is in the eating.
– Miguel de Cervantes (1547-1616)

Whether seeing is believing, as when Othello challenged Iago to demonstrate Desdemona’s fidelity (or lack thereof), or whether proof has more to do with tasting as Cervantes suggested, proving patentability often hinges on the quality of experimental evidence.

Obviousness is one of patent law’s basic requirements.  Section 103 of 35 U.S.C. provides that even if an invention is novel (as defined in Section 102), a patent may not be obtained if the “differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date to a person having ordinary skill in the art to which the invention pertains.”

In assessing whether or not a claimed invention would have been obvious, patent examiners look for differences between a claimed invention and prior art and decide whether the person of ordinary skill in the relevant field would have found it obvious to deviate from the art teachings in a way that arrives at the claimed invention.  When the claims are at least new, and there are unexpected and valuable results from the invention, the applicant is usually in a strong position to demonstrate nonobviousness.

In KSR International Co. v. Teleflex Inc., 550 U.S. 398 (2007), the Supreme Court “raised the bar” for nonobviousness, but even its expanded view emphasizes  predictability as a hallmark of obviousness (see USPTO guidelines in Part IV of this series).  As I noted in Part IV, the cure for KSR is experimental results.

Usually, inventors work in crowded fields.  Related work is published in
patent applications, scientific articles, product brochures, technical bulletins, and the like.  Scientific journals have proliferated almost beyond comprehension (to more than 25,000), and we will soon have over 9 million issued U.S. patents.  Consequently, most patented improvements are incremental tweaks, not Nobel Prize-worthy breakthroughs.  Yet even small advances can be patentable because the hurdle for establishing nonobviousness is relatively modest.  The chemical arts are mature but less predictable compared with the electro-mechanical arts, so experimental results are often crucial for satisfying a patent examiner that an allowance is warranted.

What quality of proof is needed to establish nonobviousness?  Must the evidence be present in the application as filed, or may it be supplied later?  Briefly, the proof needs to be enough to satisfy the examiner that the prior art would not have suggested at least one claim element, and that the claims are “commensurate in scope” with the showing of nonobvious results.  Consider claim 1 of U.S. Pat. No. 5,455,215:

1.  A supported catalyst comprising:
(a) from about 5 to about 95 wt.% of lithium phosphate; and
(b) from about 5 to about 95 wt.% of a high-purity silica support;
wherein the silica support contains at least about 98 wt.% of silicon dioxide.

The inventor discovered that lithium phosphate on high-purity silica makes a good catalyst for isomerizing propylene oxide to allyl alcohol while producing reduced amounts of by-products (propionaldehyde, acetone, and 1-propanol).  Lithium phosphate on ordinary silica (94% SiO2) was already known for the same reaction, making an experimental demonstration crucial.

Table 1 shows the results obtained by the inventor with high-purity silica, showing higher selectivity to allyl alcohol in experiments performed using 25-60 wt.% lithium phosphate:

Table 1.
Propylene Oxide Isomerization to Allyl   Alcohol using Lithium Phosphate on High-Purity Silica1
Product Selectivities
Ex. # Li3PO4   (wt.%) PO conversion (%) Allyl alcohol Propionaldehyde Acetone 1-Propanol
4 25 39 92 0.5
5 37 42 93 4.4 1.8 0.4
6 50 68 94 0.45
7 60 80 93 0.45
C8 37 34 88 6.8 2.9 0.65
1  Examples 4-7 use high-purity silica (HP-321   silica, a product of PQ, 99.6 wt.% SiO2).    Comparative Example 8 uses ordinary silica from United Catalysts,   Inc., which has an SiO2 content of 94.0 wt.%.

While the application was pending, the examiner rejected the claims.  She explained that the experimental showing was not commensurate in scope with the claims because the claims encompassed 5-95 wt.% lithium phosphate.  In response to the rejection, the inventor performed additional experiments to prove that catalysts with as little as 5 wt.% and as much as 95 wt.% Li3PO4 did, in fact, deliver superior allyl alcohol selectivity.  The results were supplied in a declaration under 37 C.F.R. § 1.132.  The additional results convinced the examiner to allow the broad claim as originally filed.  Ideally, these results would have been available and included in the original application.

The moral of the story?  Arguments alone won’t cut it: “Show me, don’t tell me.”  To taste, smell, touch, hear, and see is to believe.  Experimental results are important evidence for proof of nonobviousness, especially when prior art is close.  When the results are such that no one with ordinary skill could have predicted the outcome in advance with any reasonable degree of certainty, patentability is likely.  Finally, the quality of the experimental showing needs to be commensurate in scope with the claims.  When it comes to patent applications, give the examiner “ocular proof.”

Stay tuned for Part VI of our Basic Patent Law series!

– Jon Schuchardt
Check out Jon’s bio page


This article is for informational purposes, is not intended to constitute legal advice, and may be considered advertising under applicable state laws.  The opinions expressed in this article are those of the author only and are not necessarily shared by Dilworth IP, its other attorneys, agents, or staff, or its clients.