Is it legal to write an logical equation for a FPGA LUT in claims of a patent?

Hmm. I assume you mean "acceptable" to the USPTO instead of legal. I suppose since Xilinx does hardware, then its claims would be in gates rather than an equation which could ambiguously be construed as hardware, software or mathematics. Concise and simple are not the focus of the claims section of the patent. The claims have to be narrowed so they don't intrude on other patents. If you want a simpler and easy to follow explanation using the equation notation, you can put it in the preferred embodiment section.

Brad Smallridge aivision.com

Hi Brad, Thank you for your response.

1. Yes, the 'legal' should change to 'acceptable'.

1. I agree with your opinion: "If you want a simpler and easy to follow explanation using the equation notation, you can put it in the preferred embodiment section. " The question arises when the logic equation in LUT is described in the preferred embodiment section, but their correspondent logical circuits are not described in a provisional patent application. When I file for regular patent application later, claims would be invalid because the appropriate circuits are not described in provisional patent application.

So I want to know if there is an approved patent with logical equation in its claims or if there is someone having experienced similar scenario, but was declined by USPTO.

Thank you.

Weng

You are asking the wrong people.. you need to ask a patent attorney. They are better at filling in the grey areas which is what you want... After all.. if what you were doing was smart.. it would already be done.. and if it is.. you had better have a better attorney then they do :-)

besides.. you are asking a public domain news group.. therefore anything you try to patent later and have describe here has been released into the public domain before the patent has been applied for :-)

Simon

Simon, I am asking the right persons who did some inventions before and might have good experiences with the problem I have met and I am asking for their advices.

I didn't leak any information about my inventions. Never! But for advices I would like to ask and don't know well.

How do you know a better layer who, for example, is the first time dealing with your knowledge area? When you ask layers, they always have advice for you, even though they are a novice one, or their knowledge is in different area.

Weng

Sim> You are asking the wrong people.. you need to ask a patent attorney. They

Finding a patent attorney with FPGA experience might be difficult. One way to find one, I suppose, is to look at some of the prior art, and see if the attorney is close by and still in practice. The more work you do on your own, the cheaper it is in attorney fees.

I don't see anything wrong with Weng asking questions to the group. He didn't reveal any innovation and was just asking about a procedural matter of patent writing.

I am not even so sure that revealing the innovation would void his opportunity to patent the idea, only put him at risk for someone beating him to file, and he already has a provisional patent. I believe that the "offer for sale" still triggers starts a one year deadline to get your patent filed. And then after that there is a one year deadline to get you foreign patents.

As to Weng's original question about provisional patents, I am not able to answer. When I applied for patents, provisional patents didn't exist.

Brad Smallridge w w w . a i v i s i o n. c o m

You can file for a US patent up to a year after having divulged the idea. That grace period does not apply to foreign filing. There you lose the right to file immediately after divulging. So, foreign filing is more demanding, not less.

As far as equations vs LUTs, I think it makes no difference. But equations may be more widely understood. BTW, the OP is confusing in the example, using a logic equation that is actually AND and OR...

Peter Alfke (with about 30 patents, but all filed by company patent lawyers)

Weng Tianxiang schrieb:

After all it is a LUT, so why not describe it as a LUT? List the output for all 16 input combinations. It is not more conscise but it is simpler than doing it in english.

Kolja Sulimma

Hi Peter, Thank you for your response.

You are a famous inventor in Xilinx and I have read many your patents and learn a lot from your patents.

As a starter for an inventor, I would like to do more myself to save first investment. The best ideal way for me to follow is to get first patent filed and successfully approved by PTO. I know it is very difficult, but It should be much easier than to learn English as 2nd language. When you have first successful experiences with patent application, then it will go smoother for next patent applications.

I think it is better to ask for advices and suggestions on the groups and to get first hand experiences from other experts and to avoid misstep as much as possible. I met a layer who hasn't finished his patent license testing yet and prepared to open the patent application business and to help me file patent applications.

I have read many patents from Xilinx and especially pay attentions on their claims. No patent claims from Xilinx contain any logical equations. I did remember once I read a patent that is not Xilinx's, but certainly contains an equation. But I cannot find it any more.

Using a logical equation for LUT in claim area in a patent certainly helps explain the idea of the invention. But Xilinx's layers never use them, even though in the description area logical equations are used. So I guess there are some rules in USPTO forbidding to use logical equations for LUT in patent applications.

Weng

Peter Alfke wrote:

You should be aware that 'Clarity' and 'Patent' are often mutually exclusive :) Patent lawyers have motivation to obfuscate, for many reasons. Patents are merely a license to litigate, (and an income stream for the lawyer) so they tend to break them into many small claims, that can be argued. If there is prior art, it also helps to sound a lot different, even if you are the same. This also helps to get over the first hurdle, of Patent examiner.

Most (all?) FPGA patents will be electronic searchable, so scan those yourself, and then "work your claim into the gaps" between those patents.

-jg

DISCLAIMER: I am not a lawyer, but I have watched them on TV and they all have better hair than me, so I know this is not a career for me.

Correct spelling is lawyer.

Using a lawyer who hasn't yet passed the appropriate tests might be cheap, but may not be the best idea. A poorly written patent may still get issued, but will be easier to invalidate later.

That's because Xilinx does not typically file systems patents. They don't care how the parts are used, just that they are used by many customers. This is one of the reasons why you can't find details of LUT contents. Another really important one in your case is the following question: Does your idea REQUIRE that it be implemented in a LUT, or is your idea DEPENDENT on being implemented in a LUT, or is your idea a NEWER/BETTER LUT. If your answer is no to all of these (and I am guessing it probably is) then you probably do not want to tie you patemt application to implementation in a LUT. In fact, tying it to details of LUT implementation provides a huge hole for someone else to implement the idea in non-LUT stuff and get around your patent. Same thing for implementation in an FPGA. You probably should not require FPGA implementation to practice your idea, since an ASIC, or a bag of TTL chips would also bypass your patent.

Xilinx files patents because they don't want someone else to make FPGAs that use the technology that they have invented. This is independent of the LUT contents, which is why you don't see patents from Xilinx that refer to specific contents.

You might find the following patent educational: 6148313

It goes to a level of detail even below logic equations, it gives the raw bit patterns of the LUTs, since this is part of the preferred embodiment. You will find no reference to LUTs in the claims though. The patent should show how the claims could be implemented, but the claims leave it far more open to cover other implementations that depend only on what is in the claims.

The patent is the first to my knowledge that describes addition through code compression (population counters), but the details of the compressors is not in the claims. The primary claim of the patent does not depend on code compressors.

Again, unless your patent can only be implemented in LUTs, you probably do not want to restrict your patent by mentioning LUTs in the claims section. (But remember, I am not a lawyer).

Philip

What does a good haircut cost in Sunnyvale? :)

They also seem to file patents on novel applications of their FPGAs. My guess is this is to prevent anyone limiting what Xilinx customers can do with Xilinx FPGAs - a kind of defensive patenting on behalf of their customers.

John

One of the big problems in defining a patent in the terms of logic is that it is too specific if your patent covers and/or logic. I'll just use nand/nor logic. That's a good reason why there is no logic in Xilinx's patent. As mentioned Patents have to be as broad as possible to cover as much as possible so that even if it so much as smells the same, your patent will cover it. And that's why you need an expensive patent lawyer

Simon

Hi Jim, I disagree with your opinion: "You should be aware that 'Clarity' and 'Patent' are often mutually exclusive".

I found that a Xilinx patent defines a 1-bit CPU that is capable to do addition, subtraction and multiplication.

While doing addition and subtranction, the patent correctly lists its equation. But in claim area, it describes it in a XOR and inverter to describe the adder/subtractor. I found that I cannot change the equation for the LUT, but it is easy for me to change the logic to another logic implementing same equation.

That is the reason why I want to use logical equation in claims, not gate circuit descriptions. For example, you can concisely describe an addition/subtraction with a logical equation, but there are many different logical circuits to implement the same equation.

Weng

Jim Granville wrote:

Anything that is divulged in a public forum can constitute "prior art". I have been part of a counter-legal action related to postings I have made. So keep posting away if you want to be "prior art" and hope that the "truth" will come through at some point.

RAUL Not An Attorney