IP Law Daily, PATENT—D. Ariz.: On-sale bar invalidated condensation-preventing “Door Miser” patent, (Mar 25, 2014)

By Mark Engstrom, J.D.

A patent pertaining to a “Method and Apparatus for Reducing Energy Use by Refrigeration Door and Frame Heaters” (the “Door Miser” patent) was invalid because the claimed invention was on sale and in public use more than one year before the patent application was filed, the federal district court in Phoenix has ruled (Supermarket Energy Technologies, LLC v. Supermarket Energy Solutions, Inc., March 20, 2014, McNamee, S.). The court granted summary judgment of patent invalidity in favor of the alleged infringer, Supermarket Energy Solutions (SES).

Background. The purpose of the claimed invention—the “Door Miser”—was to prevent condensation from forming on the glass doors of commercial refrigeration units by heating the doors when condensation began to form, instead of continuously heating them, which was less efficient. At least three “semi-discrete” versions of the Door Miser existed: the “humidistat” version, the “120-volt” version, and the patented version. During his deposition, the inventor of the Door Miser stated that numerous 120-volt Door Misers had been sold before the critical date, but denied that those devices were the patented iteration.

Procedural posture. The court construed five elements of the asserted claim and granted SET summary judgment on the issue of infringement. Based on discovered information, however, SES sought a finding of patent invalidity because the claimed invention was on sale and in public use more than one year before the patent application was filed.

Applicability of On-Sale Bar. The on-sale bar was applicable when two conditions were met before the critical date: (1) the claimed invention had to be the subject of a commercial offer for sale and (2) the invention had to be ready for patenting. A “definite sale” satisfied the first condition. The second condition was satisfied by proof of a reduction to practice before the critical date, or by proof that the inventor had prepared drawings or other descriptions of the invention, prior to the critical date, when the descriptions were sufficiently specific to enable a person skilled in the art to practice the invention.

In this case, the inventor admitted in his deposition that the Door Miser sold extremely well before the pre-critical date, and the patentee—Supermarket Energy Technologies (SET)—did not deny that pre-critical date sales had occurred. Because the uncontroverted evidence showed that pre-critical date sales had indeed occurred, no reasonable jury could conclude otherwise. SES thus carried its burden regarding the first condition of the on-sale bar.

With respect to the second condition—in this case, whether the potentially invalidating prior art had been reduced to practice—SES argued that the “pre-critical date” Door Misers “worked for their intended purpose.” Evidence in the record that supported that argument included assertions in a promotional brochure and a solicitation letter, corroborated by the inventor’s deposition, that the pre-critical date devices were selling “extremely well,” were “very profitable,” and had achieved “amazing test results.”

SET argued that the pre-critical date Door Miser did not work for its intended purpose because the promotional brochure claimed energy savings of 98 to 99 percent. However, a co-owner of SET’s predecessor in interest testified that that the “evolved iteration” of the Door Miser achieved only a 60 to 70 percent energy savings for freezers and an 80 to 90 percent savings for coolers. Even when the court inferred that the devices worked poorly, no reasonable jury could conclude that the pre-critical date devices did not function at all.

The court concluded that the pre-critical date devices were workable and useful, and thus worked for their intended purpose. Because the pre-critical date Door Misers had worked for their intended purpose, they were reduced to practice and ready for patenting. Consequently, both conditions to the applicability of the on-sale bar were satisfied.

Anticipation and Obviousness. For the pre-critical date Door Miser to invalidate the Door Miser patent, SES had to show that the on-sale device: (1) fully anticipated the claimed invention or (2) would have rendered the claimed invention obvious by the addition of the on-sale device to the prior art. SES argued both anticipation and obviousness.

The court compared the characteristics of the pre-critical date device with the limitations of the “infringed” claim of the Door Miser patent. The infringed claim had five means-plus-function limitations: (1) sensing means; (2) means for controlling power; (3) control means; (4) means responsive to conductivity; and (5) means for measuring resistance. According to the court, the fourth and fifth limitations were part and parcel of the control means limitation. The court noted that, to show that a means-plus-function limitation was present in the prior art, a challenger had to prove that the corresponding structure—or an equivalent—was present in the prior art.

Both the sensing means and the means for controlling power limitations were present in the prior art, the court concluded. With respect to the control means, all of the evidence indicated that the pre-critical date device had a control that would activate the refrigeration door or frame heater, using a signal, when the sensors detected condensation. Therefore, there was a functional identity between the pre-critical date control and the control means limitation in the infringed claim.

Although the function was the same, the inventor’s testimony did not indicate whether the function was accomplished in substantially the same way. Nevertheless, the evidence before the court indicated that the circuit described as the corresponding structure to the control means function was prior art, and it worked in substantially the same way to achieve substantially the same result as the circuit that necessarily must have been used in the pre-critical date device.

The pre-critical date device thus embodied the sensing means, the means for controlling power, and the control means limitations from the infringed claim. Because the court’s definition of the control means limitation necessarily encompassed the remaining limitations of “means responsive to conductivity” and “means for measuring resistance,” all of the limitations from the infringed claim were present in a single prior art reference—the so-called pre-critical date device.

Invalidity. Because all of the limitations from the infringed claim were present in the pre-critical date device, the Door Miser that was sold before the critical date fully anticipated each and every limitation of the infringed claim, thereby invalidating the Door Miser patent.

Even if the control means threshold detector circuit was not present in the same pre-critical date device that had both the sensing means and the means for controlling power limitations, the patent would be invalid for obviousness. Therefore, the hypothetical combination of the sensing means and the means for controlling power with the non-equivalent control means was a prior-art reference.

The court was left with the “abiding conviction” that it was highly probable that at least one of the pre-critical date devices embodied each and every limitation in the infringed claim. Even if the pre-critical date Door Misers did not embody the control means, the sold devices clearly rendered the claimed invention obvious by their addition to prior art.

Because SES provided clear and convincing evidence that the Door Miser patent was invalid, no reasonable jury could find otherwise. That result was in accord with the purpose of the on-sale bar because the inventor had commercially exploited his invention outside of the period that was offered for a legal monopoly.

The case is No. CV-10-2288-PHX-SMM.

Attorneys: Ray Kendall Harris (Fennemore Craig PC) for Supermarket Energy Technologies, LLC. Albert Lee Underhill (Underhill Law Office PLLC) for Supermarket Energy Solutions, Inc.

Companies: Supermarket Energy Technologies, LLC; Supermarket Energy Solutions, Inc.

Cases: Patent ArizonaNews