Patent law does impose a duty of due diligence on a company learning of a patent that it may be infringing. A defendant found guilty of willful patent infringement faces the prospect, but not the guaranteed promise, of additional damage award against it. Additional damages may include paying the plaintiff's attorney's fees, and/or up to triple the nominal infringement damages awarded. A determination of willfulness is circumstantial, on a case-by-case basis.

The common tactic to avoid willfulness is an opinion of counsel - a written opinion from a patent attorney that the company's products don't infringe the patent claims, and/or that the patent claims are invalid by virtue of prior art. Such opinions are expensive, but the blowback of willfulness has been a chilling prospect. Historically, there has been a presumption of adverse inference regarding willfulness if a defendant could not produce such an opinion at trial.

The Federal Circuit upturned precedence with regard to willfulness in its ruling in Knorr-Bremse v. Dana (Fed. Cir. 2004) (01-1357).

We now hold that no adverse inference that an opinion of counsel was or would have been unfavorable flows from an alleged infringer's failure to obtain or produce an exculpatory opinion of counsel. Precedent to the contrary is overruled.

Determination of willfulness is made on consideration of the totality of the circumstances, see Gustafson, Inc. v. Intersystems Indus. Prods., Inc., 897 F.2d 508, 510 (Fed. Cir. 1990), and may include contributions of several factors, as compiled, e.g., in Rolls-Royce Ltd. v. GTE Valeron Corp., 800 F.2d 1101, 1110 (Fed. Cir. 1986) and Read Corp. v. Portec, Inc., 970 F.2d 816, 826-27 (Fed. Cir. 1992). These contributions are evaluated and weighed by the trier of fact, for, as this court remarked in Rite-Hite Corp. v. Kelley Co., 819 F.2d 1120, 1125-26 (Fed. Cir. 1987), "'[w]illfulness' in infringement, as in life, is not an all-or-nothing trait, but one of degree. It recognizes that infringement may range from unknowing, or accidental, to deliberate, or reckless, disregard of a patentee's legal rights."

The artificiality of business-as-usual infringement while clutching an opinion seems bygone, but that's not to say that an opinion still wouldn't help.

All that said, throwing money speculatively on patent applications, without knowing the prior art, is imprudent. Moreover, selling in a market with limited freedom to operate owing to patents signals only two reasonable strategies: get patents or get out.

Defensively, having patents affords counterclaim potential. And actively patenting is surely a "best practice" for any technology company. Besides, if a company doesn't proactively cite the patent prior art, a patent office action may do the job for it. Further, knowing the prior art offers an excellent opportunity to fortify and extend a patent application.

One suggestion to actively patent and avoid willfulness: create a separate patent holding company. A subsidiary patent holding company can turn its parent's technologies into patents, advise the parent discretely regarding infringement potentialities and possible workarounds, all the while providing some cover in regard to the parent's willfulness of patent infringement. Such an arms-length relationship can enhance the potential for a better patenting regime while limiting liability.