diff options
| author | Werner Lemberg <wl@gnu.org> | 2020-08-17 09:00:33 +0200 |
|---|---|---|
| committer | Werner Lemberg <wl@gnu.org> | 2020-08-17 09:00:33 +0200 |
| commit | 64515718b77f0ddd446cdb016c46ed658a14c71b (patch) | |
| tree | 16d81a1e92ee81861da4f30d7c45d5addec19f69 | |
| parent | 25a01e3b4793e958003d3a426a040a5c769ffbe5 (diff) | |
patents.html: ClearType patents have expired.
| -rw-r--r-- | patents.html | 125 |
1 files changed, 9 insertions, 116 deletions
diff --git a/patents.html b/patents.html index bbc5f01..1652618 100644 --- a/patents.html +++ b/patents.html @@ -90,11 +90,13 @@ <!-- ************************************************** --> - <div id="other-patents"> - <h2>ClearType Color Filtering Patent Issues</h2> + <div id="cleartype-patents"> + <h2>The ClearType Color Filtering Patents Have Expired!</h2> - <p>A survey from June 2007 shows no less than ten patents - from Microsoft that cover ClearType.</p> + <p>Since August 2019, all patents related to ClearType color + filtering have expired worldwide.</p> + + <p>The affected patents were</p> <div class="quote"> <p><a href="https://patents.google.com/patent/US6219025"> @@ -150,7 +152,7 @@ pixel sub-components of a display device</em></a></p> </div> - <p>Essentially, these patents cover several different + <p>Essentially, these patents covered several different things, which can be grossly sub-divided into</p> <ul> @@ -174,120 +176,11 @@ Hitchcock's whitepaper</a>.</p> </div> - <h3>Patent Claims, Prior Art, and Validity</h3> - - <p>Steve Gibson claims that - the <a href="https://www.grc.com/ctwho.htm">technique used by - ClearType is a reinvention of a 20-years old thing used on - the Apple II</a>. His exact words are</p> - - <div class="quote"> - <p>Thus, Microsoft's ‘ClearType’ application of - sub-pixel text rendering does not represent the dramatic - breakthrough that they claim and <em>it can not be the - valid subject for intellectual property - acquisition</em>.</p> - </div> - - <p>(emphasis added).</p> - - <p>Unfortunately, we believe that Mr. Gibson doesn't - understand patent law well. Under the current US regime, - any minor improvement to a previous technique can be - considered an ‘invention’ and - ‘protected’ by a patent under the right - circumstances (e.g., if it is not totally trivial). If we - look at - the <a href="https://www.google.com/patents/US6219025">first - ClearType related patent mentioned above</a>, we see that - the <a href="https://www.google.com/patents/US4136359">Apple II - Wozniak patent</a> covering this machine's display technique - is listed <em>first</em> in the patents' citations. This - shows that both Microsoft and the patent examiner who - granted the patents were aware of this ‘prior - art’.</p> - - <p>We are not trying to defend Microsoft here, just wanting to - avoid feeding false hopes to people who would like to see - the patent revoked.</p> - - <p>Another popular view is - that <a href="https://answers.google.com/answers/threadview?id=723683">these - patents are too general to be enforceable</a>. Well, to be - fair, some of the claims in these patents do indeed use - rather vague descriptive terms (even for a patent lawyer or - an ‘expert in the field’). This is - absolutely <em>not</em> surprising, it is a direct - consequence of how the patent game works.</p> - - <p>We won't cover this in greater detail since there - are <a href="https://www.iusmentis.com/patents/claims/">many</a> - <a href="https://www.tms.org/pubs/journals/JOM/matters/matters-9007.html">interesting</a> - <a href="https://en.wikipedia.org/wiki/Claim_(patent)#Basic_types_and_categories">pages</a> - on the subject. However, in case you invalidate a single - patent claim (e.g., with prior art), that doesn't mean the - whole patent is busted. Any other independent <em>and</em> - dependent claim can still be enforced.</p> - - <p>Some of these patents have up to 40 claims. Invalidating - them is going to need <em>serious</em> prior-art, even if - there are also strong chances to invalidate the most general - claims in there. For example, many of the cheap LCD screens - on digital cameras have used a screen where each pixel is - either red, green, or blue, with colour images directly mapped - to them; they have been doing it for years, even when - displaying text or menus, and this corresponds exactly to what - the most general claims cover. If we can find a proof that - the technique was deployed before the patent's filing date, we - could have valid prior art to bust these.</p> - - <h3>Possible Work-Arounds</h3> - - <p>People have proposed alternatives to the ClearType color - filtering method. A very good example is - the <a href="http://www.oyhus.no/SubLCD.html">SubLCD</a> - technique, which employs a different way to use sub-pixels - compared to Microsoft's ClearType implementation. Its - author even says it doesn't infringe the ClearType - patents.</p> - - <p>Unfortunately, the FreeType team doesn't share this - enthusiasm. The reason is precisely the very vague patent - claims described previously. There is a non-negligible - (even if small) chance that these claims also cover the - SubLCD technique. The situation would probably be different - if we could invalidate the broader patent claims, but this - is not the case currently.</p> - - <h3>Does FreeType Implement Any of the Patented Techniques?</h3> - - <p>Technically, no. The patents cover the whole process of - generating and displaying sub-pixel images. Since the font - engine doesn't do the display part, it cannot infringe. - Apart from that, FreeType has provided the capability of - converting vector shapes into un-filtered sub-pixel images - for a long time.</p> - - <p>By default, FreeType's scan-line converter returns - ‘gray’ sub-pixel images, where for each pixel - the color components are equal (this is, R=G=B). The result - is visually identical to gray anti-aliasing and cannot - infringe any of the ClearType patents.</p> - - <p>Similarly, the LCD-specific filtering API is disabled by - default, which means that it returns an error and doesn't - alter sub-pixel images.</p> - - <p>You can override these limitations by activating option - <code>FT_CONFIG_OPTION_SUBPIXEL_RENDERING</code> in - FreeType's <code>ftoption.h</code> configuration file, but - you should do that at your own risk.</p> - <!-- ************************************************** --> <div class="updated"> - <p>Last update: 13-Feb-2018</p> + <p>Last update: 17-Aug-2020</p> </div> </div> </div> @@ -354,7 +247,7 @@ <a href="#bytecode-patents">Bytecode Patents</a> </li> <li class="secondary"> - <a href="#other-patents">Other Patents</a> + <a href="#cleartype-patents">ClearType Patents</a> </li> </ul> </div> |