How to Conduct a Professional Patent Search for Your Invention

Key Takeaways

• A professional patent search is critical to ensuring your invention is unique before filing a patent application.
• Conducting a search yourself can be a good first step, but hiring a professional patent search service or attorney increases accuracy.
• International patent databases should be included in searches to avoid conflicts in other jurisdictions.
• Understanding patent classifications and advanced search techniques can improve the search's effectiveness.
• A Freedom to Operate (FTO) search helps determine if an invention infringes on existing patents.
• The USPTO, WIPO, and Google Patents are valuable free resources for conducting a preliminary patent search.
• Patent landscapes and analytics provide insights into market trends and competition.
• UpCounsel provides access to experienced patent attorneys for conducting professional patent searches and ensuring compliance.

What is a Patent Search?

A patent search verifies that an invention is original by checking patent databases for a similar invention before the inventor spends time and thousands of dollars applying for a patent. The United States Patent and Trademark Office (USPTO) will reject a patent application if a valid patent already exists for the same invention.

Some entrepreneurs may try to do their own patent search to avoid spending money on hiring an organization that performs patent searches.

However, inventors should be aware of potential problems before conducting a patent search. These include:

• Searching for patents is very difficult. Inventors commonly fail to find patents that a professional patent search organization or patent attorney would discover. The search is only as good as the keywords entered, and without experience, inventors often won't enter the optimal keywords. Most patent descriptions are also represented by drawings which are not searchable using keywords.
• The patent collections of most websites are also limited. For example, the USPTO website doesn't show full-text patents issued before 1976. This won't concern people working in high-tech fields, but may be a serious limitation for someone with a more traditional invention.

Patent attorneys typically suggest that conducting your own patent search is a good first step, but additional measures should be taken to confirm whether a valid patent already exists.

Types of Patent Searches

Conducting a patent search goes beyond simply checking for existing patents. Different types of searches serve unique purposes, including:

• Novelty Search (Patentability Search): Determines if an invention is new and patentable.
• Freedom to Operate (FTO) Search: Identifies whether an invention might infringe existing patents.
• Invalidity Search: Challenges an existing patent by finding prior art.
• State-of-the-Art Search: Examines industry trends for strategic R&D planning.
• Patent Landscape Search: Provides a broad analysis of patents in a specific field.

A professional patent search can encompass multiple search types to help inventors and businesses make informed decisions.

Steps to do a Patent Search

The following steps will yield the most productive results in your patent search:

1. Brainstorm terms or phrases. Choose a term that might appear in the patent description, such as "insulating beverage container," and type it into the search box of your chosen patent search engine.
2. Search for patent classifications. The USPTO search is considered the best place to start. In the search box at the top right of the USPTO homepage, enter in quotes CPC Scheme (Cooperative Patent Classifications) and your chosen keywords.
3. Browse relevant results. The Patents Full-Text and Image (PatFT) database will help you find the most relevant classifications for your information. Check their relevancy using the CPC Classification Definition which is often linked to your results.
4. Get the right number of results. If the search returns too many results, try searching for different terms from your brainstorming list or refining the search using advanced search functions. If it doesn't return any search results at all, use different terms from your brainstorming list or synonyms. The International Patent Classification Catchword Index can be useful if you still aren't getting results.
5. Assess the patents. Once you have a manageable number of results, click on the listed patents with your selected CPC classification and compare them to your own invention. Review them and decide which are the most relevant by scanning the abstracts and representative drawings on the front page. Note the numbers and Cooperative Patent Classifications of the most similar inventions. It's smart to repeat the process using a variety of keywords to get the most complete picture.
6. Evaluate the patents more closely. Once you have a selection of the most relevant patents, take a more in-depth look at them. Note any similarities to your own invention. Focus on the additional drawings pages, specifications, and claims. Also note the references, as they may lead you to other relevant patents.
7. Conduct further searches. Repeat your CPC classification search using the Applications Full-Text and Image AppFT database. Then widen your search to use keywords without classifications in the PatFT and AppFT databases and perform classification and keyword searches on the other websites and resources listed above.
8. Look to different websites. Using a variety of online sources at the same time can be helpful. The strengths of several websites will complement one another, making the search process easier.

Common Mistakes in Patent Searches

Even experienced inventors can make errors when conducting patent searches. Some common mistakes include:

• Using overly broad or narrow keywords: A well-optimized keyword strategy helps find relevant prior art.
• Relying solely on one database: Searching multiple patent databases, including international ones, ensures thoroughness.
• Ignoring expired patents: Even expired patents can impact the Freedom to Operate (FTO).
• Overlooking non-patent literature (NPL): Industry papers, scientific journals, and product documentation may contain relevant prior art.

Professional patent search firms and attorneys utilize advanced classification-based searching, Boolean logic, and AI-assisted tools to enhance accuracy.

Resources for a Patent Search

A number of credible resources can help people in their patent search. These include:

• The USPTO's Patents Full-Text and Image search page: This should be the first stop for anyone conducting a patent search. The site offers an intuitive search function and helpful guide to educate inventors on its features. However, its online search will not show full-text patents issued before 1976.
• Free Patents Online: This free, fast-loading site provides copies of patent documents in PDF form. This helps users view the illustrations contained within patent application more easily than searching through the USPTO.
• The Global Patent Network: This is an initiative between the USPTO and State Intellectual Property Office of the People's Republic of China. Its database includes full-text Chinese patents, English translations, and complete document images.
• European Patent Office's Worldwide Espacenet patent database: This is another valuable international resource.
• Other International Property Offices: Official bodies in several countries, including Australia, Canada, France, Great Britain, Israel, and Taiwan, also have searchable databases.
• Google Patent Search: This Google website is very fast, with a database that stretches back further than the USPTO's online search and Free Patents Online. It has a relatively small number of search fields though which limits its search capabilities and also doesn't always feature the most recent patents.
• Patent Application Information Retrieval (PAIR) system: IP customers can use this system to easily and securely retrieve and download information about patent applications and their statuses.
• The Patent Official Gazette: Inventors can also browse through patents issued within the week in the electronic version of this publication. Users can search new patents by their classification or type (utility, design, or plant). This is an excellent source for up-to-date information often overlooked by other patent databases.
• Common Citation Document application: This website application is another good source of up-to-date citation information regarding patent applications. It consolidates information from all five participating intellectual property (IP5) offices so you see all results for the same invention produced by various offices on one page.
• Publication Site for Issued and Published Sequences: This website has sequence listings, tables, and other mega items for granted United States patents and published United States patent applications. Access the relevant document detail page and then submit a sequence identification number or mega table identification number to see all sequences and tables for listed patents and publications.
• Patent Assignment Search: This website has a searchable database of patent assignments and ownership changes.
• The USPTO Public Search Facility in Alexandria, Virginia, and local Patent and Trademark Resource Centers: These brick-and-mortar facilities let you search through patents online, in print, and on microfilm. They also have staff that may be able to assist in your search or train you in the best patent searching techniques.

Advanced Patent Search Tools & Databases

In addition to the standard USPTO search, inventors and businesses should explore:

• WIPO PatentScope: International patent applications under the Patent Cooperation Treaty (PCT).
• Espacenet: European Patent Office’s extensive database.
• The Lens: An open-access patent search platform offering citation analysis.
• Derwent Innovation: A professional tool that categorizes patents based on novelty and legal status.
• USPTO Patent Public Search (PPUBS): Replaces older USPTO search systems with a more user-friendly interface.

For a comprehensive professional patent search, combining AI-driven patent analytics with human expertise is becoming increasingly essential.

Common Abbreviations Used in Patent Searching

A number of abbreviations are commonly used in the area of patent searching. Understanding the most common will help you in your own searching. These are:

• AADR: assignee address (complete string)
• ABST: abstract
• AC: assignee city
• ACLM: claims
• ACN: assignee country
• AGTC: agent address city
• AGTCN: agent country
• AGTN: agent name
• AN: assignee name
• AGT: agent
• APD: filing date
• APN: application number
• CCL: U.S. class
• AS: assignee state
• ASEX: assistant examiner name
• DN: document number (also PN, meaning patent number)
• ECLA: ECLA classification
• FOS: field of search
• FREF or FREFN: foreign patent reference
• IADR: inventor address
• IC: inventor city
• ICN: inventor country
• IN: inventor name
• IPC: IPC classification
• IPCR: revised IPC classification
• IS: inventor state (within the U.S.)
• ISD: publication date
• KCOD: Kind code
• OREF: other references
• PARN: parent case
• PCCL: primary class
• PD: publication date
• PEX: primary examiner name
• PRICN: priority country
• PRIN: priority number
• PRIR: foreign priority
• PT: document type
• REF or REFN: U.S. patent reference
• SPEC: specification
• TTL: title

Patent Search Strategies for Optimal Results

Professional patent searchers use specialized strategies, including:

• Boolean Searching: Using operators like AND, OR, and NOT to refine searches.
• Citation Searching: Examining patents cited in similar technologies.
• Legal Status Tracking: Identifying patents that are expired, abandoned, or invalidated.
• Competitor Monitoring: Watching for patent trends within a specific industry.

These approaches ensure a deeper, more strategic patent search, reducing the risk of legal conflicts.

Understanding Patent Documents

Structure of a Patent Document

Patents follow a standardized format, with sections identified by numbers in parentheses, known as INID codes. These codes help classify different parts of the document, making it easier to interpret.

Type of Patent Document

The heading of a patent document typically states its type, such as:

• United States Patent – A standard utility patent.
• United States Design Patent – Protects the ornamental design of a functional item.
• United States Plant Patent – Covers new plant varieties.
• Patent Application Publication – Indicates a patent is still in the application phase.
• Reissued Patent – A modified version of a previously granted patent.
• Defensive Publication – A disclosure that prevents others from patenting the idea but does not grant exclusive rights.
• Statutory Invention Registration – A now-defunct system that allowed inventors to make an invention public without obtaining a patent.

Below the document type, the inventor’s name appears. If there are multiple inventors, only the first is listed, followed by "et al."

Patent Number and Letter Codes

Each patent is assigned a unique number, sometimes accompanied by a letter code indicating its classification. Common codes include:

• AI – Additional improvement patents (1838-1861).
• B – Re-examination certificate, signifying the patent was reviewed.
• D or Des. – Design patent.
• H – Statutory invention registration (1985-2013).
• NP – Non-patent literature, not issued by USPTO.
• PP or Plt. – Plant patent.
• RE – Reissue patent.
• RD – Reissued design patent.
• RP – Reissued plant patent.
• T – Defensive publication (issued between 1968 and 1987).
• X – Patents issued before 1836 when patents were not numbered.

Post-2001 Letter Codes

Since January 2, 2001, patent numbers include a suffix letter to indicate publication status:

• A1 – First publication of a patent application (A2, A3, etc., for subsequent publications).
• A9 – Corrected published patent application.
• B1 – Utility patent issued without prior publication.
• B2 – Utility patent issued after prior publication.
• C1 – First re-examination certificate (C2, C3, etc., for subsequent ones).
• E1 – Reissue patent.
• F1 – Re-examination certificate of a reissued patent.
• H – Statutory invention registration.
• P1 – Plant patent (pre-2001) or plant patent application published after 2001.
• P2 – Issued plant patent without pre-grant publication.
• P3 – Issued plant patent that was previously published.
• S – Design patent.
• X6 – Post-issue patent document (e.g., disclaimer or correction certificate).
• X7 – Patent assignment.

Key Patent Information Sections

A patent document contains several essential components that provide insights into its legal and technical status:

Date of Issue

The official grant date of the patent issued by the USPTO.

Patent Title

Older patents often have vague titles, but newer patents are more descriptive.

Inventor(s) Information

All inventors' names are listed, often along with their respective cities or addresses.

Assignee (Patent Owner)

If the patent is not owned by the inventor, the assignee (such as a company or institution) will be listed.

Term Extension Notice

Indicates if the patent term has been extended beyond the standard duration, often expressed in days.

Application Number

A six-digit number assigned sequentially when the patent application is filed.

Filing Date

The date the application was submitted. This may not always be the earliest priority date.

Prior Publication Date

If the patent application was published before it was granted, the publication date will be included.

Related U.S. and Foreign Applications

Lists any related U.S. or international applications that share priority with the patent.

Patent Classifications

• International Patent Classification (IPC): Categorizes the patent’s subject matter.
• United States Patent Classification (USPC or CPC): Used to organize patents based on technology sectors.

Field of Search

Details the U.S. classes and subclasses the patent examiner used when assessing prior art.

References Cited

Lists previously published patents or literature that are relevant to the invention, either found by the examiner or disclosed by the applicant.

Examiner Information

Identifies the primary and assistant examiners who reviewed the application.

Legal Representation

Names the attorney, agent, or law firm that helped file and prosecute the patent.

Abstract

A brief summary of the invention, typically under 150 words.

Claims and Drawings

• Number of Claims: Specifies how many distinct claims define the patent's protection scope.
• Drawing Sheets: Many patents include visual representations to clarify the invention.

Determining Whether a Patent is Enforceable

Patent Expiration and Enforceability

A patent remains enforceable from its issue date until its expiration, provided all maintenance requirements are met. If a patent expires, it enters the public domain and is no longer enforceable.

The USPTO patent term calculator can help determine whether a patent is still valid. Additionally, checking the European Patent Office's Espacenet or Google Patents can provide further insights.

Indicators of an Expired or Invalid Patent

Several factors determine whether a patent remains enforceable:

1. Patent Number Below 5,000,000

Utility patents with numbers below 5,000,000 have expired as of August 31, 2010. Patents with higher numbers may still be valid but require further verification.

2. Conversion from Provisional to Utility Patent

In rare cases, a provisional patent is converted into a utility patent instead of filing a new application. In these cases, the patent’s term starts from the provisional filing date and may expire earlier than usual.

3. Terminal Disclaimer

If two patents claim the same invention, a terminal disclaimer limits the enforceability of the second patent. This information can be found in the USPTO Public PAIR system, specifically in the image file wrapper and continuity tab.

4. Patent Term Adjustments & Extensions

• USPTO Delays: Patents filed after May 29, 2000 may have extended terms due to patent term adjustments (PTA).
• Non-USPTO Delays: Some patents receive extensions for delays unrelated to the USPTO, such as FDA approvals for pharmaceuticals and medical devices.
• Congressional Extensions: While rare, Congress has previously extended patent terms—though no active patents currently have such extensions.

5. Re-examination Certificates

Patents under re-examination may lose some or all of their claims. The USPTO database provides re-examination certificates, which disclose any lost claims that affect enforceability.

6. Unpaid Maintenance Fees

Most modern utility patents expire if maintenance fees are unpaid. Fees are due at:

• 3.5 years
• 7.5 years
• 11.5 years

If the grace period of six months expires without payment, the patent becomes invalid. However, if the non-payment was unintentional, the patent may be revived within its original term.

7. Court-Declared Invalidity

Courts can invalidate patents, but this information is not always easily accessible. Checking LexisNexis, Westlaw, BNA USPQ, or the Public Access to Court Electronic Records (PACER) system can reveal relevant litigation records.

Final Thoughts

A patent’s validity is complex and depends on legal, technical, and administrative factors. If you are uncertain about a patent’s enforceability, consulting a patent attorney is the best course of action.

Frequently Asked Questions

1. What is the difference between a professional and a self-conducted patent search?
   A professional patent search uses advanced databases, AI tools, and classification-based searches, reducing the likelihood of missing prior art compared to a self-conducted search that may rely on limited databases and keyword searches.
2. How long does a professional patent search take?
   A basic patent search can take a few hours, while a comprehensive search with legal analysis typically takes 1-2 weeks.
3. Can I patent an idea that is already patented but not in use?
   No, an existing patent, even if not in use, can block a new patent application. You may explore licensing options or modifications to create a new patentable feature.
4. Do I need a patent attorney for a patent search?
   While not required, a patent attorney can help interpret search results and ensure you don’t infringe on existing patents.
5. How much does a professional patent search cost?
   The cost varies, ranging from $300 to $3,000, depending on the search depth, industry, and patent attorney involvement.

Searching for patents can be difficult, but it can also provide enough information to help you feel confident in the originality of your ideas and your right to pursue a patent for them. If you need help with your patent search, you can post your question or concern 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.