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Copyright & Patents/Invention claims and prior art



As the question is long, if you do not wish to read everything, please jump to the  question at the end.

For example's sake, imagine an inventor invents an electronic device which can be put on top of a television and it will change the picture from colour to black and white.

Assume that in the patent, the inventor wishes to make claims for the device which goes on top of the television only, nothing to do with colour projection, or the technologies of a television etc.

When writing the patent, the inventor considers two options :

1) Listing 'television method X', 'television method y' etc as specific prior art with which the new invention is combined.

2) Just detailing an 'image projection device' as a commonly known method in the invention and proceeding to describe to some level of detail how an 'image projection device' works.

Now I am wondering if there is a potential advantage to an inventor in choosing 2 ,and additionally not going into great detail in this regard, because:

i) If the inventor does not disclose prior art, and if it so happens that the examiner does not discover the similar prior art him/herself, then it is more likely that the examiner would view the invention as inventive (novel, inventive step etc) and thus be awarded a patent.

ii) If specific examples of prior art is listed (the patents etc) and thus are instantly known to the examiner, the examiner will start looking at the prior art to see if it does what the invention says it does, and maybe the examiner will decide 'well, this patent for a television also sometimes has the option of changing the colour level in a picture, so this is not a new invention'

On the other hand, maybe in some way it can be counterproductive for patent applications to be overly generic in their descricptions of prior art, or lacking in detail. Perhaps a patent application can be rejected on the grounds that it doesnt go into enough detail about known methods, or 'punished' in that sense for not being descriptive enough.

So, in light of the above, my questions are:

1) When writing a patent, is it necessary (mandatory) to describe all the technology, steps, methods, prior art etc related with the invention, or is it only necessary to describe the technology, setps etc related with the specific CLAIMS for which protection is sought?

Thanks very much in advance for any help.

Your question is not completely clear to mme. But I think you get the answer you want below:

When writing a patent application it is always necessary to mention the relevant prior art.

If you do not mention it yourself, the examiner will ask you to add what he considers as the closest prior art. The better you do this yourself from the start, the more clearly it will be what you see as your invention.

Your statements under i) and ii) are rather speculative. The clearer the prior art is described from the start, the better.

As far as your questions in the final paragraph are concerned, let me say the following:
In the claims you define what protection you seek. In the first part of the claim you state the prior art (in your case some thing like "Television set ...". Then after the words "characterised by" you describe (clearly!) in which technical measures your invention differs from the prior art.

So, stated otherwise, in your case it will not be necessary to describe how a television set works. That is the state of the art. It is only necessary to describe clearly how your device on top of the television set changes the colour picture to B&W.

Rene Hasekamp.

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Rene Hasekamp


I can answer questions about European patent law and practice. My experience mainly lies in the Dutch patent practice. I am not familiar with other patent systems than the European and Dutch systems, although I am familiar with general issues regarding patents. Please don`t ask me questions, specific for US patent law or any other non-European patent law.


I have been a patent examiner in the Netherlands Patent Office for 35 years. Now I am retired. I have been a deputy judge for patent cases in The Hague's District Court from January 1991 until June 2011.

I graduated in Chemistry and Law at Leiden University. I have worked in the Netherlands Patent Office as an examiner for 35 years until my retirement in 2003. I was appointed as a honorary deputy judge for patent cases in 1991. After my retirement I still work at a few cases on patent law in The Hague District Court.

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