How can I determine if a US patent is also protected in Canada? 3 Answers as of April 04, 2011

1) If a patent has been registered in the US, how can I determine, from the patent doc, if it is protected in Canada? If not, where should I go? 2) Is it possible to patent an incremental add on to a current patent, if this current patent has not claimed what is being considered for add-on?3) If a number of claims are made for a patent, is it considered infringement ONLY if all claims are violated, just 1 claim, or how many?4)

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Michael M. Ahmadshahi
Michael M. Ahmadshahi | Michael M. Ahmadshahi, Ph.D., Esq.
1) US patents are valid and enforceable only within the United States. They do not protect you outside of US including Canada. It is possible that the patent has a sister international patent enforceable in Canada but you best talk to either the USPTO (United States Patent & Trademark Office, Inventor Assistant Center), a patent agent, or attorney to guide you through the USPTO and other international databases to find out if such sister patent exists.

2) Yes it is as long as the add on (a) is not already described in the existing patent and (b) it is not an obvious version of the existing patent.

3) Only one claim is enough to sue for infringement. Other claims can be used as backups.
Answer Applies to: California
Replied: 4/4/2011
Malhotra Law Firm, PLLC
Malhotra Law Firm, PLLC | Deepak Malhotra
1. There is a database called Inpadoc that allows you to search patent family trees and to find corresponding foreign patents. Access is not cheap. Attorneys will usually have access via a commercial service such as Dialog. If you want to search for free, it is possible to search the Canadian patent office records at You could search based on the inventor name, for example.

2. Yes, if the improvement is not obvious. However, the fact that you obtain a patent does not mean that you do not infringe the underlying patent. It is quite possible that you will need to obtain a license from the original patent owner to be able to manufacture your patented product. If the original patent holder likes your improvement, a cross-license deal may be possible, giving the original patentee the right to use your improvement in exchange for you getting the right to use their patent, though the original patent holder is not obliged to make a deal.

3. If any one claim is infringed, a patent is infringed.
Answer Applies to: Washington
Replied: 4/1/2011
DANIEL NESBITT | Hasse & Nesbitt
1. Canadian patents: The following link takes you to the patent database at the Canadian Intellectual Property Office: Using Advanced or Boolean search tabs, you can try searching for a Canadian equivalent using inventor's name or other data from the US equivalent. If you don't find it, it might not have been filed in Canada, or you might not be searching correctly. Otherwise, any patent attorney can help you.
2. Yes, possible, but the patent's entire disclosure, not just the claims, are prior art.
3. One infringes by infringing one or more claims.
4. I don't believe you should try to figure this out on your own. Your questions show you need help.
Answer Applies to: Ohio
Replied: 4/1/2011
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