If you’ve been following Apple’s ongoing patent battle with Samsung, especially the cases being tried in California, then you’re probably familiar with U.S. District Court Judge Lucy Koh. She’s the one trying to wrangle these two beastly legal teams while sorting out Apple’s claims and Samsung’s defensive tactics.

Judge Koh has taken a no-nonsense tack towards the tactics of both companies. At one point in a trial back in October, Koh held both the Samsung Galaxy Tab 10.1 and the iPad over her head and asked the lawyers from Samsung and Apple to tell her which one was which. Court correspondent Dan Levine said that it “took them a while to do so.”

Apple is trying to prove that Samsung is infringing on two design patents that refer to the look and feel of iDevices, these are U.S. Design Patent D558,757 and U.S. Design Patent No. D618,678.

But it hasn’t been all in Apple’s favor. Judge Koh says that, while the Samsung tablet may look very similar to the iPad, there is actually a device that appeared on the scene much earlier than either of those. Back in 1994, the news conglomerate Knight-Ridder produced this concept video for a ‘tablet newspaper’. The features and use case are startlingly similar to what we use tablets for today.

In fact, the inline video playback that is demonstrated in the video isn’t something that appeared on the iPad until as recently as iOS 4. Previously, the video would always enlarge to full screen. Now, this is a concept, obviously, and never made it to market. The technology of the time wouldn’t even have supported something like that existing.

There were tablets in between that and the iPad, of course, but none were as thin and light as it appears. They couldn’t make it happen either. It took 17 years for this kind of experience to get here in a form that was purchasable by humans.

This tablet concept was used by Judge Koh to refute Apple’s claims that the iPad design patent was being infringed, because it may constitute prior art. The case is ongoing, but this definitely put a dampener on that line of attack for Apple. When Judge Koh used the Knight-Ridder concept as an example, the Samsung counsel on the case seemed to know that this was as a good thing.

The knowledge that this tablet looks a lot like the iPad is nothing new, but its use as a refutation of Apple design patents is interesting.

The case is still ongoing but at this point Koh says that she will not grant a preliminary injunction against the sale of Galaxy devices based on one of the technical patents that Apple exercised, even though she says that Samsung does infringe on them.

It is unclear whether she will do so on any of the design patents yet, but evidence that something very much like the iPad was conceived nearly two decades earlier couldn’t hurt Samsung’s case that the design of the current crop of tablets is ‘inevitable’.