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Re: lzw patent search (fwd)

---------- Forwarded message ----------
Date: Sun, 9 Mar 2003 20:04:01 +0100
From: Arnoud Galactus Engelfriet <galactus@stack.nl>
To: Drew Scott Daniels <umdanie8@cc.UManitoba.CA>
Subject: Re: lzw patent search


Drew Scott Daniels wrote:
> When do all the lzw related patents expire? I've heard different stories
> and am confused by all the different patents that seem to exist for lzw.
> I also am unsure as to how to search for information about each of the lzw
> patents.

If you go to http://ep.espacenet.com and enter a patent number
in the right search box (US4558302 for example), you get an
overview of all the 'corresponding' patents. In this example:

CA1223965, DE3476617D,  EP0129439,  JP2610084B2, JP5068893B,
JP60116228,  JP7249996,  JP8237138

The EP patent was granted in German, France, Great Britain
and Italy. I'd have to check one of the databases at work
to determine whether the German patent given above is the
same as the EP patent.

In all countries except the USA, patents expire 20 years
from the day of filing. The EP 129439 was filed on 18.06.84
so it expires on 18.06.2004 (meaning 19.06 is the first
'patent free' day).

The USA has a somewhat complex regime, since they moved from
"17 years after grant" to "20 years after filing".

Kind regards,

Arnoud Engelfriet

Arnoud Engelfriet, Dutch patent attorney - Speaking only for myself
Patents, copyright and IPR explained for techies: http://www.iusmentis.com/

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