Key Takeaways

  • A search for similar patents is essential to assess novelty and avoid infringement.
  • Patent classification systems like CPC and IPC help identify related inventions.
  • Even if similar patents exist, an invention can still be patentable if it's non-obvious and novel.
  • The Doctrine of Equivalents assesses infringement when products aren't identical but operate similarly.
  • Provisional patents, NDAs, and trade secrets can offer alternative or supplemental protection.

Similar Patents

When someone comes up with an idea that they think could be original, the first step to take is to conduct a search for similar patents. Similar patents, are considered “prior art,” and could potentially prevent an inventor’s product from being patentable because someone already had that idea and protected it. Prior art consists of everything that is relevant to an inventor’s claim of originality.

Prior art does not necessarily preclude a similar idea from being patentable. There are millions of ideas and products that exist, so at some point, you will run into a product or idea that is similar to yours. The real question then becomes exactly how similar the two products are and if the subsequent idea builds upon the prior art in a relevant useful way. Even if there is prior art, an inventor has the opportunity to differentiate his or her product in a way that convinces the government that it deserves to have its own patent.

How to Search for Similar Patents

To determine whether similar patents exist, inventors should conduct a comprehensive patent search. This involves exploring databases such as:

  • USPTO Patent Full-Text and Image Database (PatFT)
  • Google Patents
  • Espacenet (European Patent Office)
  • PatentScope (WIPO)

Using keyword searches alone may miss relevant results, so inventors should also consider patent classification codes such as:

  • CPC (Cooperative Patent Classification)
  • IPC (International Patent Classification)

These classification systems group similar technologies and can help identify overlapping or related inventions more effectively than keywords alone.

Professional patent searches are often advisable, as attorneys and patent agents are experienced in navigating classification hierarchies and uncovering prior art that may not be easily discoverable through general searches​.

Obtaining a Patent Despite the Existence of Prior Art

As stated above, prior art does not necessarily preclude an inventor from subsequently patenting his or her similar idea or product. A few questions to ask yourself to determine whether your product has a reasonable chance at success are:

  • Will your product be in the same industry as the patent holder?
  • Is the existing patent strong, and if so, how broad is it?
  • How technically complex is the product?
  • Are there other competitors in the same industry?

There is always a chance that the original patent owner will never know or find out about your patent. However, this is a risky strategy and the original holder can always file a claim of infringement to try and get your patent revoked. But, they must show that your product is more than just “similar.”

A person can obtain a patent even if there is a similar patent that already exists if the newer product expands upon or improves the original patent’s process. In fact, a large majority of patents are filed under this exception. In this case, the new patent would be protecting the improved process, as opposed to the actual product that the process is improving. However, the “improvement” must be nonobvious (e.g., an ordinary mechanic would not be able to create your invention) and must be able to pass a test. An invention would be considered obvious if differences between the product sought to be patented and the product already patented would have been obvious at the time the original patent was filed. Some differences to patented products that would not typically be considered patentable are:

  • Substituting one material for another; or
  • Changes in size

Because of the complexity of patent law, it is advised that a person seek a registered patent attorney or patent agent to help navigate all these possible issues. For example, a patent attorney could help prevent a person from unintentionally admitting to an infringement of an already-patented product that could later be held against him or her in court.

To help figure out whether prior art exists, a patent attorney or patent agent should run a search through the Patent Application Information Retrieval (“PAIR”) portal found on the U.S. Patent and Trademark Office’s website. There you can find all the public references associated with a particular patent or patent application. One other important thing to keep in mind is whether the new patent will be filed in the same country as the existing patent. One way to avoid a similar patent is to make, use, sell, etc. your product in a different country than that of the existing patent.

Strategies When Faced with Similar Patents

If you find similar patents during your search, you still have strategic options:

  • Design Around Existing Patents: Modify your invention’s features or processes to avoid overlapping claims. Even a small but meaningful improvement can make a difference.
  • File a Continuation-in-Part (CIP): If you're improving upon your own previous invention, a CIP can secure rights to the new subject matter.
  • Demonstrate a New and Nonobvious Use: A known product used in a novel way can still be patentable.
  • Submit a Provisional Patent Application: This gives you a priority date while buying time (up to 12 months) to further develop your invention or conduct market research.

Also consider whether the existing patent is:

  • Expired or abandoned
  • Narrow in scope, leaving room for broader claims
  • Geographically limited, meaning it might not block your product in other markets​

“Doctrine of Equivalents” Test

The patent system in the United States adopted a test known as the “Doctrine of Equivalents.” This test essentially helps determine how “similar” a product is to one that is already patented. The test poses three different questions:

  1. Does the newer product substantially perform the same function?
  2. In substantially the same way?
  3. That ends substantially in the same result?

Alternatives to Traditional Patent Protection

In some cases, especially where the invention might not qualify for a full utility patent, inventors can consider other methods of protecting their intellectual property, such as:

  • Provisional Patents: Offer temporary protection and an early filing date.
  • Non-Disclosure Agreements (NDAs): Help preserve confidentiality when sharing ideas with potential partners or investors.
  • Trade Secrets: Beneficial for processes or formulas not easily reverse-engineered (e.g., Coca-Cola’s formula).
  • Creative Commons or Open Source Licensing: For software or creative works, licensing terms can govern usage without formal patenting.

These alternatives are particularly useful when patentability is uncertain or when time and resources are limited​.

Additional Legal Doctrines Related to Similarity

In addition to the Doctrine of Equivalents, inventors should be aware of the All Elements Rule, which states that a claim is only infringed if every element is present in the allegedly infringing product or its equivalent. This complements the Doctrine of Equivalents by requiring detailed analysis of claim language and product features.

Also, prosecution history estoppel may limit a patent owner’s ability to invoke the Doctrine of Equivalents if they made narrowing amendments during prosecution to gain approval. These legal nuances are critical when assessing risk and deciding how to proceed with a similar invention.

Frequently Asked Questions

  1. Can I still get a patent if something similar already exists?
    Yes, if your invention offers a non-obvious improvement or serves a new function, it may still be patentable.
  2. How do I search for similar patents?
    Use tools like the USPTO database, Google Patents, and patent classification codes (CPC/IPC) to uncover related inventions.
  3. What happens if I accidentally infringe on a similar patent?
    You could face legal action. A patent attorney can help you assess risk and adjust your product to avoid infringement.
  4. Is a provisional patent enough to protect my idea?
    A provisional application secures a filing date but must be followed by a non-provisional application within 12 months for full protection.
  5. What if the similar patent is expired?
    If a patent has expired, its content enters the public domain, and you may freely use or build upon it.

If you need help with filing a similar patent or general issues on similar patents, you can post your legal need on UpCounsel’s marketplace. UpCounsel accepts only the top 5 percent of lawyers to its site. Lawyers on UpCounsel come from law schools such as Harvard Law and Yale Law and average 14 years of legal experience, including work with or on behalf of companies like Google, Menlo Ventures, and Airbnb.