TechRoadmap Directions logo

Issue 6                                                                               September 2001

In this Issue


This is the sixth issue of Directions, a newsletter from TechRoadmap Inc. discussing intellectual property issues and ideas. As always, we hope to stimulate you to examine and improve your own IP practices.


In this month's issue we examine the effects of  the apparent imprecise use of language in the specification portion of the patent. If you ask what a patent is protecting, everyone will tell you to look at the claims. But the claims don't tell the whole story in many instances. For example, the claims sometimes use expressions that are defined in the specification, Another example in which the claims do not stand alone is when the invention incorporates prior art technology - your patent is not expected to detail what is common practice in your field. The issue raised in S3 Incorporated vs. nVidia Corporation is about the degree of latitude you can expect if you are imprecise with your definitions and rely on what you think is commonly understood knowledge. 

Feel free to share this newsletter (see copyright notice below) and to provide feedback by e-mail to:

Patent Strike ForceSM

That's precisely what I think I might have meant to say!

Many clients question the elaborate patent documents that result from their short but sweet invention disclosures. "Lawyers get paid by the word." is a comment heard more than once, with the implication that the length of the patent specification is due more to financial considerations than to legal requirements.

This month's patent case shows the fine line between excess verbiage and a defensible patent. The patent in question has only about one and a half pages of detailed description. A model, perhaps, of conciseness. Unfortunately, S3's competitor, nVidia, felt too much had been left to the reader's imagination and was able to convince the District Court the many of the claims were fatally indefinite. Although S3 was ultimately triumphant on appeal, they could have saved themselves time and expense by being a bit more expansive in their specification.

There were two problems in their specification. First, the internal definition of what the VGA controller produced was imprecise. The focus of the invention was the integration of multiple video functions into a single IC; it was not the controller function per se. Thus, when referring to a secondary mode of operation (the direct mode) the specification blithely states that the controller provides video display information directly to the D to A converter. Unfortunately, up to this point, the controller had only sent "video information" to RAM in which it was converted to "video display information", and it was upon this small point that nVidia jumped. Thus, by not being precise about what the controller could or could not produce or what was meant by video information versus video display information, S3 had a problem.

The second problem in the specification was its failure to provide at least an example structure for carrying out a function included in the claims. That is, the claims call for a means to select one or the other inputs to the DAC, but the description never says what that might be. Thus, S3 relied on what they felt was common knowledge, at least within their field. The difficulty here, of course, is knowing a priori what will be taken as common knowledge. Although ultimately vindicated by the Appeals Court, S3 could have avoided this difficultly by at least making a reference to an appropriate selector structure - it was one of only five major functional blocks in their invention.

So, what can you do?

  • Review the definitions in your application - make sure that every term you use is used consistently in the document. Also be sure that each term that is not guaranteed to be generic is defined in the document.

  • Give examples of how functions are performed - surely there are one or more alternative ways to perform the function you are claiming...that's probably why you want to claim the function in the first place.

  • Err on the side of explaining "the obvious" - although you don't want to start every patent at the beginning of time, don't let your familiarity with the subject blind you to the need to teach your invention adequately. Remember, almost by definition, you are an expert, someone more knowledgeable than a person of ordinary skill in the art.

Nothing in the preceding article should be construed as legal advice. TechRoadmap Inc serves as an interface between companies and their legal counsel.

Return to Contents

Interesting Patent Case
The risk in having an  imprecise specification.

In S3 Inc. v. nVidia Corp, S3 appealed the summary judgment that invalidated many claims in its patent US 5,581,279 on the ground of indefiniteness. The patent describes an integrated circuit for use in a computer video display card. The patent describes two modes of operation; the direct mode and the indexed mode. In both modes a video controller produces a data stream that in some sense defines the sequence of pixel values for the display. In the direct mode, the 8-bit output of the [VGA] video controller is selected by a "selector" and sent directly to a digital-to-analog converter (DAC), whose output is the signal that drives the monitor. The video controller output is also sent to an random access memory (RAM) that acts as a lookup table, converting the 8-bit controller output into 256 different words, each of which can be 18 or 24 bits wide. In direct mode these data are ignored. In indexed mode, however, the selector selects the RAM output for transmission to the DAC and ignores the signals coming directly from the controller. 

nVidia argued successfully before the District Court that seven of the patent's claims where invalid on the grounds of indefiniteness. The basis of their argument was that in both the specification and in the claims the terms "video information data" and "video display information data" are used in ways that make the claims unclear; so unclear that they did not meet the statutory requirement of "particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention". Basically they argued that it was unclear whether the controller produces "video information" (which feeds the RAM) or "video display information" (which feeds the DAC and is produced by the RAM).

The District Court agreed. The Court also held that the claim language "digital-to-analog means...for selectively receiving either..." of the two data streams was also indefinite because the structure claimed by the selectivity limitation is not disclosed in the specification as required.

The Appeals Court majority rejected the decision of the District Court, saying that while it is true that the claims require two different outputs from the video controller and this requirement is (arguably) inconsistent with the description in the specification, they "conclude that a person of skill in this field would understand the claims when viewed in the light of the description". They said "the claims are not a self-contained explanation of every step. That is not the role of claims". "The purpose of claims is not to explain the technology or how it works, but to state the legal boundaries of the patent grant". The Appeals Court pointed out a single line in the specification - "In certain modes it may be desirable for the VGA controller to...provide video display information directly to the DAC" and concluded "that a person skilled in this field would understand the meaning and scope of the data streams as set forth in the claims." Thus, it ruled, there was no indefiniteness in the claims.

The District Court had also ruled that the use of the terms "means...for selectively receiving", without either a description of the electronic structure of the selector or the details of its electronic operation in the specification, was indefinite. The District Court stated that "the disclosure must be judged on the basis of the 'common experience' of 'those outside the relevant art'. " [emphasis added] The Appeals Court strongly stated that this ruling was "incorrect, and must be reversed" The Appeals Court noted that "patent documents need not include subject matter that is known in the field of the invention [emphasis added], for patents are written for persons experienced in the field..." To hold otherwise, they continued, "would require every patent [to be] a technical treatise for the unskilled reader." Finally, referencing an earlier decision, "Patents are written to enable those skilled in the art to practice the invention, not the public."

Return to Contents

IP Links
US Patent office Searchable database of all US Patents and, now, published patent applications.
The Patent Cafe - an on-line source of interesting insights into current IP issues.
EKMS Inc. - a company with whom we've worked that provides a range of IP management services including portfolio analysis, deal-making, and process improvement.

Return to Contents

IP Glossary

Industry's Best Glossary

Return to Contents

Copyright 2001 TechRoadmap Inc.  All rights reserved. This newsletter, or portions thereof, may be copied and distributed, so long as this is not done for profit, proper acknowledgement of the source is made, and this copyright notice is included. If you wish to be removed from this mailing list, please simply reply to this message with the word REMOVE in the subject line.