Wellman, Inc. v. Eastman Chemical Co., CAFC, Case 07-CV-0585, Decided April 29, 2011 (Focus on Best Mode issue of the case)

Bernadette McGann and Shuji Yoshizaki | May 11, 2011

ベストモード要件は2パートテストからなる。Green Edge Enters., LLC v. Rubber Mulch Etc., LLC, 620 F.3d 1287, 1296 (Fed. Cir. 2010).  第一に、裁判所は、出願時に発明者がクレーム発明を実施するためのベストモード(最良実施形態)を所有していたかどうかを判断する。この「ベストモード」はクレーム中の少なくとも一の限定事項に関連しなければならない。第二に、もしも発明者が他の実施例と比較して一つの実施例について主観的な選好を持っている場合、裁判所は発明者がその好適な実施例を公衆から隠したかどうかを判断しなければならない。





The best mode requirement has two parts.  Green Edge Enters., LLC v. Rubber Mulch Etc., LLC, 620 F.3d 1287, 1296 (Fed. Cir. 2010).  First, the court must determine whether, at the time of filing, the inventor possessed a best mode of practicing the claimed invention.  This “best mode” must be related to at least one limitation in the claim.  Id.  Second, if the inventor has a subjective preference for one mode over all others, the court must then determine whether the inventor “concealed” the preferred mode from the public.  Green Edge, 620 F.3d at 1296. 

If a patentee does not disclose in its specification the best (or preferred) mode of practicing the claimed invention, the patent is invalid.  The fact that the best mode was known in the art or even a commercialized product does not save the patent. 

In this case, the court found the best mode violation since the patentee did not disclose a PET resin recipe and/or the specific ingredients through which the best mode of the PET resin product is achieved based on at least one inventor’s subjective preference of the PET resin at the time of filing the application.

The patent applicant should be aware that non-disclosure of the best or preferred mode, specific ingredient or trade name of the specific ingredient that achieves the best mode in order to protect the recipes as a trade secret may result in a best mode violation under 35 USC §112, first paragraph.


The Wellman patents are directed to polyethylene terephthalate (hereinafter PET) resins for use in plastic beverage containers.  The claimed PET resin is a slow-crystallizing PET resin.  By the time Wellman filed the application leading to the patent in dispute in May 2004, Wellman had commercialized a slow-crystallizing PET called Ti818 based on the claimed PET resin.  The Wellman patents do not disclose the recipe for the Ti818 resin, do not disclose any other specific PET resin recipes, and do not disclose novel features of the elements that comprise the claimed PET resin.

Representative Claim 1

A polyethylene terephthalate resin, comprising:

less than about 25 ppm of elemental antimony, if any; and

more than about 5 ppm of elemental phosphorus; and

wherein the polyethylene terephthalate resin has a heating crystallization exotherm peak temperature (Tch) of more than about 140oC at a heating rate of 10oC per minute as measured by differential scanning calorimetry;

wherein the polyethylene terephthalate resin has an absorbance (A) of at least about 0.18 cm-1at a wavelength of 1100 nm or at a wavelength of 1280 nm; and

wherein the polyethylene terephthalate resin has an L* luminosity value of more than about 70 as classified in the CIE L*a*b* color space.

District Court Proceedings

The trial court granted Eastman’s motions for summary judgment to invalidate the Wellman patents for indefiniteness and granted in part Eastman’s motion for summary judgment for invalidity for failure to disclose the best mode. Wellman appealed the decision of the trial court.

The Law

A patent specification shall set forth the best mode contemplated by the inventor of carrying out his invention.  35 U.S.C. §112, ¶1.

Best mode issues can arise if any inventor fails to disclose the best mode known to him or her as of the date the application for patent is filed.  Pannu v. Iolab Corp., 155 F.3d 1344, 1351 (Fed. Cir. 1998).

Invalidation based on a best mode violation requires that the inventor knew of and intentionally concealed a better mode than was disclosed in the specification.  High Concrete structures, Inc. v. New Enter. Stone & Lime Co., 377 F.3d 1379, 1384 (Fed. Cir. 2004).


Suggested Alternative Course of Action:  Recite your best mode of practicing your claimed invention in a dependent claim. 

U.S. patent law grants an applicant the right to exclude others from practicing said invention.  However, one of the requirements an applicant must satisfy in order to be granted the right to exclude is to disclose the best mode for practicing said invention.

A commercial embodiment of said invention may be considered persuasive evidence of a best mode, especially if the inventors consider the commercial embodiment to be the best mode, as was the case with the Wellman patents. Thus, if there is a commercial product of said invention, an applicant may consider presenting a claim directed towards that product.  Nonetheless, Applicants must disclose the elements/novel features of their claimed invention within the specification.  An inventor may represent the contemplated best mode by a preferred range of conditions or by working examples.  In re Honn, 364 F.2d 454, 462 (CCPA 1966). 

Here, the CAFC held that Wellman failed to disclose the best mode of the invention.  This was evidenced by the inventor’s declarations and admissions of best mode, the commercial embodiment of the invention and even Wellman’s request to seal the proceedings in order to protect their trade secret.  The CAFC herein affirmed that Wellman cannot receive the right to exclude others from practicing their invention while maintaining the best mode for practicing said invention as a trade secret.

In the Wellman patents, the patentee could have claimed the composition of the PET resin.  The patentee could have claimed the preferred ranges for each component of the composition.

While failure to disclose a commercial embodiment of the claimed invention does not automatically invalidate a patent under §112, it may be considered evidence of failure to disclose the best mode if the inventors consider the commercial embodiment to be the best mode of practicing their invention.  Claiming the best mode of an invention may ensure adequate disclosure of the best mode while providing the patentee with the right to exclude others from practicing the best mode of said invention.  Applicants may consider presenting a narrow independent claim directed towards the commercial embodiment of their invention. 

Lastly, if the inventors do not subjectively believe there is a best mode of practicing the invention, then there may be nothing to disclose.  However, as everyone has an opinion about everything, it is unlikely that none of the inventors of an invention would state that there is no best mode of practicing their invention.  Therefore, one of the safest options to ensure a valid patent and to provide patentees with full protection of their invention is disclose each inventor’s best mode of practicing their invention.

Subscribe | 登録



词典 / 辞書 / 사전
  • dictionary
  • dictionary
  • 英語から日本語

Double click on any word on the page or type a word:

Powered by dictionarist.com