> Even if someone had rushed out of the gate in 2018, they would probably not have ad products ready for a couple of years (and last year there was covid too) - and this with the most basic tech, which we know actually took significant time to be refined.

Ignorant question: are you not allowed to start developing a product, or "planning" to develop a product, before a patent it infringes on expires? I see from glancing at Wikipedia that with a US patent, "making" the item is infringement, but where is the line on that? Is it that you literally can't fully make the thing, i.e. only get 99% of the way there and you're fine? Or is it infringement to have an on-the-record chat with a buddy that you're thinking of working on X when the patent for X expires? (Responses in the form of LMGTFY are welcome, I couldn't quickly figure out how to search for this.)

> Is it that you literally can't fully make the thing, i.e. only get 99% of the way there and you're fine?

Lawyer-no-longer-practicing-patent-law here: You have to look at each individual, numbered claim (at the end of the printed patent). Treat each claim as its own infringement checklist, with each term in that claim as a checklist item. IF: Every checklist item in that claim is present in what you're doing, either literally or, as an edge case, by a "substantial equivalent," a term of art; THEN: That claim is infringed. (It only takes one infringed claim for liability.)

A canonical hypothetical claim is this: "1. A seating structure comprising: (a) a generally-horizontal seating platform; and (b) at least four legs, of substantially-equal length, each affixed, substantially orthogonally, to the same side of the seating platform to extend in the same general direction relative to the seating platform."

For that hypothetical claim, a tripod-style three-legged stool with angled legs wouldn't infringe because four legs are required for infringement. (There'd probably be an argument over whether the angled legs satisfied the "substantially orthogonally" element.)

For the same claim, suppose that you had a conventional four-legged chair with a back. That chair would infringe claim 1 because the checklist elements are all present; the addition of the back is irrelevant to the infringement analysis.

(In chemical- and biological fields, extra elements can be relevant to infringement analysis, for reasons we won't go into here.)

Another edge case: If you "induce" someone to infringe the claim, you're liable as an infringer. Still another is "contributory infringement," which I won't go into here.

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> Or is it infringement to have an on-the-record chat with a buddy that you're thinking of working on X when the patent for X expires?

No infringement there — for infringement to exist, someone has to actually make, use, sell, offer to sell, or import the subject matter of at least one issued claim of the patent.

(Usual disclaimer: I'm not your lawyer, don't rely on this as legal advice about your specific situation, small changes in facts can sometimes make a big difference in outcome, etc.)

I think the question that throwaway287391 is asking is: when in product development does patent police knock on your door and have the right to drag you to the court? If I build a factory that produces chairs, and then hoard all those chairs in my house, can I be told to knock it off? What if I build the factory and then have it just stand there, producing nothing?

> when in product development does patent police [sic] knock on your door and have the right to drag you to the court?

Generally, you can be sued for infringement whenever you make, use, etc., anything that comes within the scope of any issued, unexpired, not-yet-invalidated claim.

There's a nebulous experimental-use exception to liability; it's currently of uncertain scope [0].

> If I build a factory that produces chairs, and then hoard all those chairs in my house, can I be told to knock it off?

Generally, yes — if the chairs come within the scope of an issued, unexpired claim that hasn't yet been invalidated, then simply making the chairs constitutes infringement of that claim.

> What if I build the factory and then have it just stand there, producing nothing?

If the factory itself doesn't infringe a claim, then there's no infringement under the stated circumstances.

Same disclaimer as above.

[0] See, e.g. https://www.lrrc.com/webfiles/TCL-KK_DS.pdf (not an endorsement).

Thanks! It seems the solution is to make a ton of legs and a ton of seats, and then to not slap them together until the day the patents expire.

If I recall correctly e-ink took almost a decade to work out the very complicated processing required to produce displays with good enough quality control.

It was a really hard problem that required totally different tooling from a normal display manufacturer so I'd absolutely expect that to be a huge source of delays in getting set up.

You can't just convert an existing display factory to make e-ink displays, so the startup costs are huge and the odds are good that you'll take at least a few years to work out the quirks. Probably more like 4-6... if you get lucky and can figure out what tools to use quickly.