TAEUS War Stories: The “Art” of Searching for Prior Art

Prior art searching is often times a dull, uninteresting affair that is done on a computer searching electronic records.  Electronic database searching has its place but it often times does not yield the information needed to invalidate a patent.  Here is a true story about a prior art search TAEUS did to invalidate a Japanese patent.


The patent, in this case, had to do with a heat sink mounted on the back of a plasma display. Plasma displays generate a lot of heat due to the nature of the underlying technology, so, in order to dissipate that heat, engineers designed special heat sinks to help dissipate that heat. This patent was owned by a Japanese company, Panasonic, and they were asserting it against LG.  This particular patent also had a relatively recent date relative to the evolution of plasma display technology.


In every patent case TAEUS works on, our team first reviews the patent and claim construction. In this review, the TAEUS team concluded that plasma displays had always generated heat and the heat always had to be removed.  So, based on this deduction, the patent had a very high likelihood of prior art.


While the obviousness of this technology is pretty clear, concrete proof of prior art was needed but not available online.  So, we sent an engineer on a mission to a display library in San Jose, California. The volumes and the papers in this display library were not electronically searchable and only existed in their paper format. After several days of studying the stacks of books and papers on plasma display technology a name continuously showed up, Don Wedding.


Now the real detective work began.


We tracked Don down using social media. Wedding was 80 years old and lived just outside of Toledo, Ohio. We called his home and were promptly turned away by his daughter who said that her dad was very old and frail and wasn’t interested in talking about this kind of stuff anymore. However, we are engineers, not attorneys and engineers love to talk technology, especially technology they’ve invented. Wedding wanted to talk.


We booked a flight to Toledo, Ohio and arrived on a stereotypical dark and stormy night in December. We met Don and his daughter at his house and spoke with him about this particular patent. In our conversation, he mentioned that he had sold products into Japan 10 years prior to the priority date on the patent. He also told us that he had a storage unit with the old product and records in it.




In his old dusty storage unit, we found exactly what we’d been seeking, a 4-inch diameter display with a heat sink attached to the back of it. A heat sink attached to a display alone wouldn’t constitute prior art though, the patent also contained language that stipulated how the heat sink was bonded to the display. We looked at the bonding technique, and indeed, it was the same as the technique on the patent.  The most important discovery, however, was that Wedding’s product came out 10 years prior to the Japanese patent!


Because this was a Japanese court case, Japanese law stipulates that there had to be not only a demonstration of the technology in Japan, but the product had to have been sold in Japan as well. Lo and behold, Wedding had documented records of the display being sold and then re-sold within Japan.


Armed with this newly found information, we said our “thank you’s” to Don Wedding and flew back to sunny Colorado.  We presented this information to outside counsel and demonstrated how it predated this patent by at least a decade. The case was settled outside of court for an undisclosed amount. The Japanese company, Panasonic, that was asserting this patent against LG decided to drop the case, and the case went away.


At the time, this was most expensive prior art search that TAEUS had ever done. Total cost to LG was about $250,000.  While this may seem like a quite the price tag, it was massively beneficial to LG in terms of ROI.  LG’s line of plasma displays was very large and our detective work saved them millions of dollars.


Written by: Arthur Nutter