Conducting a patent search is one of the most important steps before filing a patent application or developing a new product. A patent search helps you determine whether your invention idea already exists, saving you time, money, and potential legal issues. The good news is that you can perform a thorough patent search for free using publicly available databases and tools. This comprehensive guide will walk you through the entire patent search process step by step, using simple language that anyone can understand.
What is a Patent Search?
A patent search is the process of looking through existing patents and patent applications to find inventions similar to yours. This type of search is also called a prior art search, novelty search, or patentability search. The goal is to discover if your invention is truly new and different from what already exists.
Why Do You Need to Conduct a Patent Search?
Before investing thousands of dollars in a patent application, you need to know if your invention can actually be patented. Here are the main reasons why patent searching is essential:
Avoid Wasting Money: Patent applications cost between $5,000 and $15,000 when you hire an attorney. If your invention already exists, you’ll save this expense by finding out early through a free search.
Determine if Your Idea is Novel: For an invention to be patentable, it must be new and non-obvious. A patent search reveals whether someone else has already patented or publicly disclosed your idea.
Understand the Competitive Landscape: Searching existing patents helps you see what competitors have invented in your field and identify opportunities for innovation.
Improve Your Invention: By studying similar patents, you can refine your invention to make it more unique and patentable.
Avoid Patent Infringement: A comprehensive search helps you avoid accidentally copying someone else’s patented technology, which could lead to costly legal disputes.
Strengthen Your Patent Application: Understanding existing prior art allows you to write better patent claims that clearly distinguish your invention from what already exists.
Understanding Prior Art and Patent Types
Before you start searching, it’s helpful to understand some basic patent concepts.
What is Prior Art?
Prior art refers to any publicly available information that existed before your patent filing date. This includes existing patents, published patent applications, scientific journal articles, product manuals, YouTube videos, blog posts, conference presentations, and products already sold in stores. If your invention appears in prior art, it cannot be patented.
Types of Patents You’ll Find
Utility Patents: These cover new and useful processes, machines, manufactured items, or compositions of matter. Most inventions fall into this category. Utility patents last 20 years from the filing date.
Design Patents: These protect the ornamental design or appearance of a product, not how it functions. Design patents last 15 years from the grant date.
Plant Patents: These cover new varieties of asexually reproduced plants. Plant patents also last 20 years from filing.
When searching, you’ll primarily focus on utility patents unless you’re designing a product’s appearance.
Free Patent Search Tools and Databases
Several excellent free tools are available for searching patents. Each has different strengths, so using multiple databases gives you the most comprehensive results.
USPTO Patent Public Search
The United States Patent and Trademark Office operates Patent Public Search, a powerful web-based application that provides enhanced access to U.S. patents and patent applications. This tool replaced older systems and offers both basic and advanced search interfaces.
Strengths: Official U.S. government database with complete patent records dating back to 1790. Includes both granted patents and published applications. Advanced search features for experienced users.
Best for: Searching U.S. patents specifically, looking up patents by number, and conducting detailed searches using multiple criteria.
Website: www.uspto.gov/patents/search/patent-public-search
Google Patents
Google Patents is one of the most user-friendly patent search tools available. It searches more than 120 million patent documents from over 100 patent offices worldwide, making it excellent for international searches.
Strengths: Simple interface similar to Google search, fast results, excellent visualization of patent relationships, includes non-patent literature from Google Scholar and Google Books, machine translation for foreign patents.
Best for: Beginners, quick keyword searches, exploring related patents, viewing patent citations, and international patent searching.
Website: patents.google.com
Espacenet
Espacenet is the European Patent Office’s free patent database. It provides access to patents from European countries and worldwide patent offices with machine translation capabilities.
Strengths: Excellent international coverage, machine translation for multiple languages, classification searching.
Best for: European patents, international searches, and finding patents in languages other than English.
Website: worldwide.espacenet.com
WIPO PATENTSCOPE
The World Intellectual Property Organization operates PATENTSCOPE, which searches international patent applications filed through the Patent Cooperation Treaty (PCT) system.
Strengths: Coverage of PCT applications, machine translation, access to patents from many developing countries.
Best for: International patent applications and patents from countries with smaller patent offices.
Website: patentscope.wipo.int
Step-by-Step Guide: How to Do a Patent Search
Now let’s walk through the actual process of conducting a patent search. We’ll use both USPTO Patent Public Search and Google Patents, as these two tools together provide excellent coverage.
Step 1: Describe Your Invention
Before you start searching, write down a clear description of your invention. Answer these questions:
- What problem does your invention solve?
- What are the main features or components?
- How does it work?
- What makes it different from existing products?
- What materials or methods does it use?
For example, if you invented a new type of smartphone case with a built-in battery, your description might be: “A protective smartphone case with an integrated rechargeable battery that wirelessly charges the phone through magnetic induction.”
Step 2: Create a Keyword List
Based on your description, make a list of keywords and phrases that describe your invention. Include synonyms, related terms, technical terminology, and common names.
Tips for Creating Keywords:
- Think broadly at first, then narrow down
- Include both technical and common terms
- Consider how others might describe the same concept
- Add related technologies or components
- Think about the function, not just the name
For the smartphone case example, keywords might include: smartphone case, phone case, protective case, battery case, wireless charging, inductive charging, magnetic charging, portable charger, mobile device case, cell phone accessory, rechargeable case.
Step 3: Start with Google Patents for Quick Keyword Searching
Google Patents is the easiest place to start because of its familiar interface.
Basic Search Process:
- Go to patents.google.com
- Enter your main keywords in the search box (for example, “smartphone case battery”)
- Review the results that appear
- Look at the titles and thumbnail images to identify relevant patents
- Click on interesting results to read the full patent
Refining Your Google Patents Search:
Google Patents automatically searches all fields including title, abstract, description, and claims. You can refine results using the filters on the left side:
- Filing/Publication Date: Focus on recent patents in your technology area
- Patent Office: Select specific countries (US, EP, WO, etc.)
- Status: Choose between granted patents and applications
- Type: Select utility, design, or plant patents
Using Advanced Search:
Click “Advanced Search” for more control. Here you can search specific fields:
- Enter keywords in the “with the exact phrase” box for exact matching
- Use the “inventor” field if you know specific inventors in your field
- Use the “assignee” field to find patents owned by specific companies
- Enter dates to limit your search to recent patents
Step 4: Use USPTO Patent Public Search for Detailed Searching
After your initial Google Patents search, move to USPTO Patent Public Search for more detailed searching of U.S. patents.
Accessing USPTO Patent Public Search:
- Go to www.uspto.gov/patents/search/patent-public-search
- Click “Launch Patent Public Search”
- Choose “Basic” search for simple queries or “Advanced” for complex searches
Basic Search Tutorial:
The basic search interface lets you search by common fields like keywords, inventor name, or publication number. Here’s how to use it:
- Select a search field from the dropdown menu (Title, Abstract, Claims, etc.)
- Enter your search term in the text box
- Use the operator dropdown to combine terms (AND, OR, NOT)
- Add additional search terms in the second text box
- Click “Search” to see results
Example Search:
- Top dropdown: “Title”
- Top text box: “smartphone”
- Operator: “AND”
- Bottom dropdown: “Abstract”
- Bottom text box: “battery case”
- This finds patents with “smartphone” in the title AND “battery case” in the abstract
Quick Lookup by Patent Number:
If you found a patent number elsewhere and want to view it, simply enter the patent number in the quick lookup box and click search. Format the number with leading zeros if needed (for example, 0123456 for patent 123456).
Step 5: Understand Patent Classification Codes
Patent classification codes are like a library system for patents. Every patent is assigned one or more classification codes based on its technology area. Learning to use these codes dramatically improves your search results.
Cooperative Patent Classification (CPC):
The CPC system is jointly developed by the European Patent Office and USPTO, with over 250,000 classification categories organized into sections A through H and Y. Each code represents a specific technology area.
How CPC Codes Work:
CPC codes follow a hierarchical structure. For example:
- H = Section (Electricity)
- H04 = Class (Electric Communication Technique)
- H04M = Subclass (Telephonic Communication)
- H04M1/00 = Main Group (Substation equipment)
- H04M1/02 = Group (Details of telephone sets)
The more numbers and slashes, the more specific the classification becomes.
Finding Classification Codes:
The easiest way to find relevant classification codes is to:
- Find a patent similar to your invention using keyword searches
- Open that patent and look for the classification codes (usually listed near the top)
- Click on those classification codes to see their definitions
- Search using those codes to find similar patents
Searching by Classification:
In Google Patents, you can enter a CPC code directly in the search box or use it in advanced search. In USPTO Patent Public Search, select “CPC Current” from the field dropdown and enter the classification code.
Step 6: Review and Analyze Search Results
Now that you have search results, you need to carefully review them to understand what prior art exists.
What to Look for in Each Patent:
Abstract: A brief summary of the invention (usually 150 words or less). Read this first to determine if the patent is relevant.
Claims: The legal boundaries of the patent protection. Claims define exactly what the patent covers. Read the independent claims (usually numbered 1, 10, 20, etc.) first.
Description: A detailed explanation of how the invention works, including alternative embodiments and examples.
Drawings: Visual representations of the invention. These are often the easiest way to understand a complex invention.
Citations: Patents cited by the patent (backward citations) and patents that cite this patent (forward citations). These help you find related patents.
Reading Patents Efficiently:
- Start with the abstract and drawings to get a quick overview
- Read independent claim 1 carefully to understand the core invention
- Skim the detailed description for relevant sections
- Check the filing and publication dates
- Note the assignee (patent owner) to understand who your competitors are
Taking Notes:
Create a simple spreadsheet to track relevant patents:
- Patent Number
- Title
- Filing Date
- Key Features
- How It Differs from Your Invention
- Relevance (High, Medium, Low)
Step 7: Expand Your Search Using Patent Citations
Patent citations are connections between patents. Every patent lists other patents it builds upon (backward citations) and newer patents that reference it (forward citations).
Finding Related Patents:
In Google Patents:
- Scroll to the bottom of any patent page
- Look at the “Patent Citations” section (backward citations)
- Look at the “Referenced By” section (forward citations)
- Click through relevant patents to expand your search
In USPTO Patent Public Search:
- View any patent document
- Scroll to “References Cited” to see backward citations
- These show what prior art the examiner considered when granting the patent
Why Citations Matter:
If you find one highly relevant patent, its citations often lead you to other important prior art in the same technology area. This technique, called “snowballing,” helps ensure you haven’t missed important patents.
Step 8: Search International Patent Databases
If you plan to sell your product internationally, search foreign patent databases to ensure your invention is novel worldwide.
Key International Databases:
European Patents (Espacenet): Search patents from all European countries at worldwide.espacenet.com
Japanese Patents: Search the Japan Patent Office database at www.j-platpat.inpit.go.jp (offers English translation)
Chinese Patents: Search the China National Intellectual Property Administration at english.cnipa.gov.cn
Korean Patents: Search KIPRIS at eng.kipris.or.kr
Canadian Patents: Search the Canadian Intellectual Property Office at www.ic.gc.ca/opic-cipo
Using Google Patents for International Searching:
Google Patents makes international searching easy because it includes patents from many countries. Use the patent office filter to select specific countries, or leave it open to search all jurisdictions.
Step 9: Search Non-Patent Literature
Prior art isn’t limited to patents – it includes any publicly available information such as scientific publications, product manuals, website content, and commercial products.
Where to Search Non-Patent Literature:
Google Scholar: Search academic papers, theses, and conference proceedings at scholar.google.com
Technical Journals: Search industry-specific publications in your technology field
Product Websites: Check manufacturer websites for product specifications and marketing materials
YouTube: Search for product demonstrations, tutorials, or technical explanations
Trade Shows: Look for product announcements at industry trade show archives
Commercial Products: Check online retailers like Amazon for existing products with similar features
Why This Matters:
Even if something isn’t patented, if it was publicly disclosed before your filing date, it counts as prior art and can prevent you from getting a patent.
Common Patent Search Mistakes to Avoid
Understanding common pitfalls helps you conduct more effective searches.
Using Too Few Keywords
Many inventors only search using one or two keyword phrases. Effective patent searches require testing dozens of keyword combinations, including synonyms, related terms, and technical jargon. Different inventors and patent attorneys describe the same concept using different words.
Stopping After Finding No Results
If your initial search finds nothing, that doesn’t mean your invention is clear. You may be using the wrong keywords, searching in the wrong classification codes, or looking in the wrong databases. Keep refining your search terms and strategies.
Only Searching U.S. Patents
Many inventors forget to search international patents. Someone in Japan, Germany, or China might have patented or publicly disclosed your invention. Use international databases to ensure comprehensive coverage.
Ignoring Pending Applications
Published patent applications (not yet granted) also count as prior art. Make sure you’re searching both granted patents and published applications. In USPTO Patent Public Search, this is automatic. In other databases, you may need to specifically include applications.
Not Understanding Patent Claims
Many people only read the abstract and title, missing the claims – the most important part of the patent. The claims legally define what’s protected. Two patents might have similar titles but completely different claim scope.
Searching Too Narrowly
If you search only for your exact invention as you envision it, you might miss patents that cover the same concept differently. Think about the broader principle behind your invention, not just your specific implementation.
Giving Up Too Soon
Patent searching is challenging and time-consuming. Professional patent searchers spend 10-40 hours on a comprehensive search. While you don’t need to be that thorough, expect to spend at least 3-5 hours for a decent preliminary search.
Ignoring Old Patents
Some inventors think old patents don’t matter. However, any patent published before your filing date is prior art, regardless of age. Sometimes the most relevant prior art is decades old.
When to Hire a Professional Patent Searcher
While you can conduct a basic patent search yourself, there are situations where hiring a professional is worth the investment.
Consider Professional Help If:
Your Technology is Highly Complex: Fields like pharmaceuticals, biotechnology, or advanced electronics require specialized knowledge to search effectively.
Significant Investment is at Stake: If you’re planning to invest hundreds of thousands of dollars in product development, spend $1,000-$3,000 for a professional search.
You Found Confusing Results: If your search revealed patents that might or might not cover your invention, a patent attorney can provide a legal opinion.
You Need a Freedom to Operate Search: This specialized search determines whether making and selling your product would infringe existing patents. It requires legal expertise.
You’re Preparing to File a Patent: Many patent attorneys recommend a professional patentability search before filing to strengthen your application and avoid wasting money on unpatentable inventions.
What to Do After Your Patent Search
After completing your search, you need to analyze the results and decide on next steps.
If You Found Identical or Very Similar Patents
If an existing patent or publication describes your exact invention, your idea is not patentable as currently conceived. However, you have options:
Modify Your Invention: Change your invention to avoid the prior art. Add new features, use different methods, or approach the problem from a different angle.
License the Existing Patent: Contact the patent owner to negotiate a license to use their technology.
Pursue a Different Idea: Sometimes the best decision is to move on to a different invention that has better patent prospects.
If You Found Related But Different Patents
If you found patents in your technology area but none cover your specific invention, this is promising. Review the differences carefully:
- Make a list of how your invention differs from each patent you found
- Identify the unique aspects of your invention
- These differences will become the focus of your patent claims
This information is valuable when working with a patent attorney to draft your application.
If You Found Very Little Prior Art
If your search found almost no related patents, one of two things is likely:
- Your invention is truly novel (great news!)
- You haven’t searched thoroughly enough (more common)
Before concluding your invention is unique, try different keyword combinations, check international databases, and consider hiring a professional searcher to verify your results.
Next Steps Toward Patent Protection
Document Your Invention: Keep detailed records of your invention’s development, including dates, drawings, and descriptions.
Consider Provisional Patent Application: File a provisional application to establish an early filing date while you continue development. Provisional applications are less expensive and give you 12 months to file a full patent application.
Consult a Patent Attorney: Even after a thorough search, consulting with a patent attorney is wise. They can provide a professional opinion on patentability and help you develop the best filing strategy.
Continue Product Development: Use what you learned from your patent search to improve your invention and make it more commercially viable.
File a Non-Provisional Patent Application: If your invention is patentable and you’re ready to proceed, file a non-provisional utility patent application with the USPTO.
Additional Patent Search Tips and Strategies
Here are some advanced tips to improve your patent searching skills.
Use Boolean Operators
Boolean operators (AND, OR, NOT) help create more precise searches:
- AND: Finds patents containing both terms (smartphone AND battery)
- OR: Finds patents containing either term (wireless OR inductive)
- NOT: Excludes certain terms (case NOT leather)
You can combine these: (smartphone OR cellphone) AND (battery OR charger) NOT leather
Use Wildcards and Truncation
Many databases support wildcards to find variations:
- Asterisk (*): Replaces multiple characters (charge* finds charge, charger, charging, charged)
- Question mark (?): Replaces a single character (wom?n finds woman or women)
Note: Different databases use different wildcard symbols, so check the help documentation.
Search by Date Ranges
Limit searches to recent patents if your technology is fast-moving, or search historical patents if your technology has been around for decades. In most databases, you can filter by publication date or filing date.
Study Patent Family Members
Patent families are groups of patents filed in different countries for the same invention. If you find a relevant U.S. patent, check if it has foreign counterparts that might contain additional information or claims.
Check Patent Legal Status
Before worrying too much about a patent you found, check its legal status. Patents expire after 20 years (utility) or 15 years (design). Expired patents enter the public domain, meaning anyone can use the technology. Also check if patents have been abandoned due to non-payment of maintenance fees.
Use the Patent Examiner’s Search
When the USPTO examines a patent application, the examiner conducts their own prior art search. You can access these search results in the patent file history (also called file wrapper) through USPTO’s Public PAIR system. This shows exactly what prior art the examiner considered relevant.
Understanding Your Patent Search Results
After spending hours searching, you need to interpret what you found.
Levels of Concern for Prior Art
High Concern – Blocking Patent: A patent that appears to cover your exact invention. Every element of your invention is described in the patent. This is the most problematic situation.
Medium Concern – Close Prior Art: Patents that share many features with your invention but have some differences. You may be able to patent your unique aspects, but the patent scope will be narrow.
Low Concern – Related Art: Patents in your general technology area but with significant differences. These help establish what’s already known but don’t block your patent.
No Concern – Unrelated Art: Patents that appeared in your search but aren’t actually relevant. Tag these so you don’t waste time reviewing them again.
Red Flags in Your Search Results
Be concerned if you find:
- Multiple patents by major companies in your exact field
- Recent patent applications covering similar concepts
- Products already on the market with your invention’s key features
- Academic publications describing your invention’s core technology
- Expired patents that describe your invention (others can use expired technology freely)
Conclusion
Learning how to do a patent search is an essential skill for any inventor, entrepreneur, or business developing new products. While professional patent searches provide the most comprehensive results, conducting your own preliminary search using free tools like USPTO Patent Public Search and Google Patents can save you thousands of dollars and help you make informed decisions about your invention’s patentability.
Remember that patent searching is both an art and a science. It takes practice to develop good search strategies, think of alternative keywords, and interpret patent documents correctly. Don’t be discouraged if your first few searches feel overwhelming – patent language is complex, and the databases take time to master.
The key steps to remember are: describe your invention clearly, create comprehensive keyword lists, search multiple databases, use classification codes to find relevant patents, review patent citations to expand your search, check international patents and non-patent literature, and carefully analyze your results to identify differences between your invention and existing prior art.
Whether you decide to proceed with a patent application, modify your invention, or pursue a different idea, the knowledge you gain from patent searching is invaluable. You’ll understand your competitive landscape better, identify potential design alternatives, and make better business decisions about where to invest your time and resources.
Start your patent search today, and take the first step toward protecting your innovative ideas. The patent databases are free, accessible 24/7, and contain a wealth of technical knowledge that can inspire your next breakthrough invention.