united-states software patents
Is Simplex noise still patent protected? (What is &quot;anticipated expiration&quot;?)
<p>According to the Wikipedia page on <a href="https://en.wikipedia.org/wiki/Simplex_noise#Legal_status" rel="noreferrer">Simplex noise</a>:</p>
<blockquote>
<p>Uses of implementations in 3D and higher for textured image synthesis are covered by U.S. Patent 6,867,776, if the algorithm is implemented using the specific techniques described in any of the patent claims. <strong>The patent is expected to expire on January 8, 2022.</strong></p>
</blockquote>
<p>That date has recently passed, but there was no update to the article about any change to the patent status. Following the reference to the <a href="https://patents.google.com/patent/US6867776" rel="noreferrer">patent</a> itself, it shows the following entries:</p>
<blockquote>
<p>2022-01-08 - Anticipated expiration</p>
<p>Status - Active</p>
</blockquote>
<p>What exactly does this mean? Is the algorithm still protected by the patent?</p>

<blockquote>
<p>What exactly does this mean? Is the algorithm still protected by the
patent?</p>
</blockquote>
<p>Assuming, without independently confirming, that the patent in question has indeed expired (and it would be very unusual for a patent of this kind to be extended near the end of its term), the claims made in the patent for which it sought patent protection are now part of the public domain and may be used without a royalty and without permission from the patent holder.</p>
<p>One should proceed with caution, however, because often an implementation of a patent also utilizes other patents with different claims that have a different expiration date. In a complex device, it wouldn't be unusual for dozens of patents to come into play. Likewise, an implementation of a patent may be associated with some trademark protections (like a distinctive, non-functional design associated with a particular company), or with derivative work copyright protections.</p>
<p>So, if you want to implement an expired patent in a manner that does not infringe other patents, copyrights, or trademarks, ideally you would confirm that there are not also other patents, copyrights, or trademarks that are still in force that govern some aspect of how you apply the expired patent.</p>
