Somewhere in almost every joint development effort is an outside scientist or engineer whose contribution nobody wants to sort out too carefully. That's exactly the fight now playing out in a Massachusetts patent case, where a judge ruled that leaving two of them off a patent application was enough to wipe out five patents at once.

Inline Plastics, which makes tamper-resistant food packaging, had been developing new packaging concepts together with a company called 4Sight Inc. After a bench trial, the judge found that two 4Sight engineers, not Inline employees, had come up with the idea for a "tear strip" feature claimed in five of Inline's patents, and should have been named as joint inventors. Because they weren't, she ruled all five patents unenforceable.

Inline is now asking the court to undo that finding, arguing it rests on "several manifest errors." Its argument isn't “yes, but we didn't mean to,” it's that the finding is wrong on the merits. Inline says there wasn't the kind of real working relationship between its own inventors and the 4Sight engineers that joint inventorship legally requires, that the specific claimed feature was developed independently in-house and doesn't appear anywhere in 4Sight's own drawings, and that neither its inventors nor the 4Sight engineers themselves ever thought the two should be listed. Notably, Inline also argues there was no reason to hide anyone in the first place since 4Sight would have assigned any rights back to Inline regardless. That last point turns out to matter a lot, with more on why below.

Why This Has Nothing to Do With Whether the Invention Is Any Good

This comes from inequitable conduct, a different question from whether a patent is valid. A genuinely novel, deserving invention can still become completely unenforceable if the company misled the Patent Office on something material, but importantly, knowingly. Getting inventorship wrong is one of the most common ways companies stumble into it, usually without meaning to.

The rule sounds simple: everyone who contributed a genuine inventive idea has to be named, no more, no less. But joint inventorship also requires some real connection between the contributors, i.e., communication, shared drawings, working toward the same idea together, not just two people or two companies independently landing on something similar. That line gets genuinely blurry in real joint development work, and blurry is exactly where these disputes live: it's Inline's central argument here, that its own engineers and 4Sight's never had the kind of working relationship the law requires, whatever similarities existed on paper.

In practice, this is easy to get wrong precisely because collaboration between organizations rarely produces a clean record of who talked to whom, who saw whose drawings, and when. Outsiders, such as vendors, development partners, joint venture engineers, are the biggest blind spot, not necessarily because anyone's hiding something, but because nobody documented the relationship while it was happening. That gap is exactly what a competitor's litigation team goes looking for years later, and it can look a lot like concealment even when the real story is a good-faith disagreement about where the legal line falls.

The consequence is severe by design: if it was knowing and material, the whole patent goes, not a claim, not a royalty, the entire asset.

The Conversation Nobody Wants to Have

Here's the part that actually plays out in practice: a company doing joint development work with an outside partner ends up with an idea that took shape somewhere in the middle, and nobody wants to sort out afterward exactly who belongs on the patent application. Sometimes that's discomfort. Just as often, it's a genuine, good-faith belief that the outside contributor's involvement doesn't legally rise to inventorship, which is exactly the position Inline is defending now, years after the fact, in front of a judge instead of around a table with its own team.

The fix is almost never "don't name the person." It's:

Get the assignment right before the work starts, not after. Making sure every consultant, contractor, or development partner agreement has a clear, present-tense IP assignment clause before that person does a single hour of work won't excuse you from the duty to name every actual inventor. That's a separate, non-negotiable obligation to the Patent Office, and no assignment clause changes who legally counts as an inventor. What it does do is take away any argument that you had a reason to hide someone, since you already owned whatever rights they had. That's the exact point Inline is now making in its own defense: that there was no motive to deceive because 4Sight's rights would have come to Inline either way. Better to have that argument available before litigation than to be building it after the fact.

No assignment on file for past work? Get one now. If that clause was missing when the work actually happened, retroactively securing a signed assignment or release, even for a modest payment, is nothing compared to losing the entire patent's value and litigation leverage.

If you conclude an outside contributor isn't an inventor, write down why at the time. Note what the relationship actually was: who talked to whom, who saw whose work, and why that falls short of joint inventorship. That contemporaneous record is the only thing that turns a defensible legal call into something other than a guess made under oath years later.

The Paperwork Is Cheaper Than the Alternative

A patent's value depends on the integrity of the process behind it, not just the invention. The agreement that assigns a development partner's rights takes an hour to draft and a signature to close. Losing an entire patent over its absence takes one bad fact pattern and a competitor's litigation team with time to dig. Fix it at intake, and the "should we name them" fight never has to happen at all.