Prior Art: The Silent Patent Killer Most Inventors Never See Coming

Before a patent is granted, one question always needs to be answered: has anyone, anywhere in the world, ever made this public before? That single question can determine whether years of work result in a granted patent or a rejected application.

But here’s what many inventors don’t realise: the threat doesn’t just come from the outside. Sometimes, the biggest risk to your patent is something you did yourself.

This post covers both sides of the prior art problem: what’s already out there in the world, and what you might accidentally be putting out there yourself.

The only protection: file before you go publicPart 1: What’s Already Out There

What counts as prior art?

Prior art is everything that was already known or publicly available before the date of your patent filing. A scientific paper, a product on the market, a conference presentation, an earlier patent, a blog post, a video online, if it was accessible to the public, it counts.

And the patent office does not limit its search to your country or your industry. A publication in Japan, a product sold in Brazil, or a patent filed in South Korea can all be cited against your application in Belgium or anywhere in Europe. Prior art is global, and it goes back as far as records exist.

Why can it kill your patent?

Novelty is one of the core requirements for a patent. If your invention has already been disclosed, even partially, it can no longer be considered new. And without novelty, there is no patent. It does not matter how much time, money, or effort you have invested. If someone else got there first and made it public, that is the end of the road.

Why a prior art search is worth your time

A prior art search before filing is one of the most valuable things you can do as an inventor. It helps you understand what already exists in your field, where the genuine gaps are, and how to position your invention to maximise the scope of your protection. It also helps you refine the claims in your application, making it stronger and harder to challenge.

Beyond that, a prior art search gives you a clearer picture of the competitive landscape. You may discover that a competitor has already filed in a related area, which could affect your freedom to operate. Or you may find that a key patent in your space has expired, opening up possibilities you were not aware of. Going in without that knowledge is rarely a good strategy, and the cost of a search is almost always far lower than the cost of a misdirected application.

Part 2: What You Might Be Doing to Yourself

Your own disclosures can count as prior art

This is the part that catches many inventors off guard. It’s not just your competitors who can create prior art against you, you can do it to yourself.

Presenting your idea at a trade fair. Publishing about it on your website. Writing about your innovation on social media. Sharing it in a pitch without a confidentiality agreement in place. Any of these can compromise your ability to file a valid patent application later. You do not need a competitor to destroy your chances. We see it happen regularly, and the inventors involved almost never realised the risk at the time.

Once it’s public, you can’t take it back

In most countries outside the United States, there is no grace period. Once something is out in the open, the clock doesn’t just start ticking, it’s already too late. A public disclosure cannot be undone after the fact.

This is especially important for companies that attend trade fairs, publish research, or pitch to investors on a regular basis. Each of those moments is a potential prior art event, if no filing has been made yet.

The only protection: file before you go public

The rule is simple in principle, but easy to overlook in practice. File first, then talk about it. Not the other way round.

If you are planning a launch, a trade fair appearance, a press release, or even an investor pitch, make sure your patent application is on file before any of those events. That single step protects everything that comes after.

Where Do You Start?

Whether you’re trying to understand what’s already out there or making sure you don’t accidentally undermine your own position, the answer is the same: get advice before you go public.

At brantsandpatents, we help you understand what is at stake, both from the outside and from within your own organisation and make sure your timing and your strategy work in your favour.