by: Joseph Page
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Patent Search

Has it been 'invented' already?

Patent Search
Related Topics: Prior Art , Patentability , Obviousness , Novelty

Patent searches are generally performed to discover whether or not a particular invention is truly original or if, in fact, it has already been patented. This tutorial will focus on searching the United States Patent and Trademark Office (USPTO) Web Patent Databases. Searching these databases allows the user to search U.S. patents from 1790 to the present.
This tutorial covers the basics of patent searching. Once you have completed the tutorial you should be able to perform a basic patent search. Expect your search to be more complex and time consuming than the one presented here. Keep in mind that the average patent search takes between 25 and 30 hours to conduct from start to finish.
It is important to remember that this tutorial is only intended to assist the user in a preliminary search. To perform an exhaustive search additional avenues must be explored such as international patent documents and the review of non-patent literature. If you have further questions about the patent application process it is recommended that you contact a registered attorney or agent.

For a listing of registered patent attorneys point your browser to http://www.uspto.gov. Click on the "How To " button, then the "How To... main page " under the Find... heading click on "a Patent attorney or agent."
(Or click USPTO_Patent_attorney_or_agent_search" id="USPTO_Patent_attorney_or_agent_search">here .)

The first step in our patent search involves brainstorming. For our purposes we will start with the idea that you have invented a new kind of computer mouse. Write down all the words you can think of that describe your invention. Click here to open a note-taking window if you would like to type your ideas on the screen. It is important to think broadly and creatively. To help, keep the following questions in mind:

  • What does the invention do?
  • What is the end result?
  • How does it work?
  • What is it made of?
  • What is it used for?
  • What problem(s) does it solve?

Index Search
The second step involves looking up the terms you have generated using the Index to the U.S. Patent Classification. The index is an alphabetical list of subject headings referring to specific classes and subclasses of the classification system. For our invention we need to look up "mouse."

  1. Point your browser to http://www.uspto.gov.
  2. Click on the "Patents" heading that appears on the left side of the screen (the fourth button down.) Click the first link to the "Patents main page."
    If you are using a browser other than IE click here.
  3. Scroll down and under the "Guides..." heading, click on "Guidance, tools, and manuals" or click here.
  4. Scroll down to the "Tools and Manuals" heading and under the "Classification:" subheading, click on the "U.S. Patent Classification (USPC) Index" link.
  5. Click on "M" for "mouse" on the "Index in HTML" row.

    TIP: Instead of scrolling down to find "mouse" in the page use your browser's find command. Go to Edit and select "Find in page..." This will bring up a window into which you can type "mouse" (again, without the quotation marks) to quickly bring up the word. Make sure that the frame that you want to find the word in is active. You can activate a frame simply by clicking anywhere within it.
  6. Under the "Mouse" heading you see that the subheading "Computer Input and Display Control Devices" seems to describe your invention. We can rule out the other subheadings, such as "multicellular living organisms." However, especially when the match is less clear, you may want to continue looking up words from your brainstorming list to better understand the classification system.
  7. Take a look at the numbers on the right side of the page. These are classification codes. They consist of a class and subclass. For computer mouse the class is 345 and the subclass is 156. The plus sign next to our classification code is a reminder that when you perform the next step, examining the Manual of Classification, you will want to look at the subclasses located near your classification for other closely related classifications.

 Classification Codes

The third step involves looking up the classification code in the Manual of Classification.

  1. Click on 156 of the classification code 345/156, next to the "Computer Input and Display Control" entry from step 2.

    This takes us to Class 345, with the heading at the top of the page, ("Computer Graphics Processing and Selective Visual Display Systems") and Subclass 156 ("Display Peripheral Interface Input Device") of the Manual of Classification.
  2. Now is the time to think about that plus sign that we saw in the Index of Classification. Remember to look around subclass 156 for any closely related classifications.

    IMPORTANT! To do so you must scroll towards the top of the page and ensure that the dropdown menu next to "Select Largest Indent Level to be Displayed" is set to Expand All Indent Levels (and be sure to hit the "SUBMIT" button). Once you've done this scroll back down to 156 - DISPLAY PERIPHERAL INTERFACE INPUT DEVICE.

    Scrolling up and down you will notice that the subclass numbers are not in perfect order. Over time the contents of some subclasses became too large to be easily managed. As more inventions were patented, those subclasses were divided into more appropriate subclasses. What is important to notice is the arrangement of the subclasses, not the numbers themselves.
  3. Notice the dots to the left of the subclass titles. These dots indicate the specificity of each subclass. As a subclass becomes more specific, the number of dots increases (from zero to seven). Zero dots indicate that a subclass title is a major subdivision within a class (such as "Display Peripheral Interface Input Device.") In our example, "Cursor Mark Position Control Device" has one dot, so we know that it is a more specifically defined classification related to "Display Peripheral Interface Input Device" (which is located right above it with zero dots). The next few items ("Including orientation sensors," "Having variable cursor speed," "Cursor key," "Joystick," "Positional storage means," and "Mouse") all have two dots, indicating that they are more specifically defined subsets of "Cursor Mark Position Control Device" (which has one dot). You'll notice that "Rotatable ball detector" has three dots, which indicates that it is a more specifically defined subclass of "Mouse" and so on. This step in the process can be confusing, so make sure that you carefully examine the sequence of dots and descriptors so that you can decide which classifications you want to investigate.
  4. There is the possibility at this point that your search strategy will need to be revised and you will need to start your search again. However, if at this point you can identify a classification that seems like a good match for your invention you can proceed.
  5. Click on the subclass number that most closely matches your invention. In this case, click on subclass 163, "Mouse."

Classification Definitions

This takes us to the Classification Definitions. This is where the working definitions for all utility subclasses of the U.S. Patent Classification System are located. Occasionally, you will find suggestions for other subclasses to consider. These suggestions can also helpful if you have been looking in the wrong classification. It is often helpful to look at the definition of the class as a whole, at the top of the page.

Patent Review

Examine individual patents to determine the originality of your invention.

  1. Click on the red "P" icon to the left of the blue subclass number 163. This will bring up a list of all the U.S. Patents in that particular classification code, in this case more than 900 patents. (You can also click on the "A" icon at the top of the classification schedule or definitions to bring up a list of published applications in a particular class.) All years have been searched and the list displays the most recent patents first. Get a preliminary feel for the group by browsing the titles that look like they might describe your invention. Keep in mind that the titles are often short and not overly descriptive. Looking at the patent as a whole is the only way to really decide whether or not the invention is similar to your own. If you conclude that this is indeed the correct classification code you must examine all the patents to determine if your invention is original.
  2. To view the patent, click on the patent number (please note: if you click on a patent number to view a patent, you will have to use the Back button on your Browser to return to this patent tutorial). If the patent was issued after 1976 you may view the full text, without images.
  3. If you want to see the full image of any patent from 1790 to the present, which includes drawings, you will need a specialized TIFF viewer. Click on the "Help" button at the top of the search results page and then click on the topic "How to Access Patent Full-page Images" to get complete instructions on downloading the free software (If you click on the "Help" button, use the Back button to return to this tutorial).

* Please Note: There are other options for viewing patents once you know what you are looking for. Click here are a few of those options (under the heading Quick Links).

  1. Be sure to look at the drawings and claims sections of individual patents. These are two quick ways to determine the originality of your invention.
  2. Also, make note of the "references cited." Listed are other patents that were thought to be closely related to the patented item.
  3. Do this for each class/subclass combination that relates to the invention.


Keyword Searching

If you are still having trouble finding a term that adequately matches your invention in the Index to the U.S. Classification System or can't find the right code in the Manual of Classification, you can do a keyword search. However, only patents back through 1976 can be searched by keyword.

  1. Go back to the USPTO's homepage (http://www.uspto.gov). Click on the "Patents" link on the left side menu and "JUMP TO:" number 5 Search Patents. On the Search page, in the left-handed, green box called "Issued Patents," click on "Advanced Search."
  2. In the Query box, type in your search terms. For our invention we enter "computer mouse" in the query box (be sure to include quotation marks around the search terms in this instance). This will return a list of all the patents that have "computer mouse" anywhere in the indexed text. (For more information on how to perform an advanced search, click on the "Help" button at the top of the page. Then click on the "How to Use the Advanced Search Page" link).
  3. Click on a patent number. Again, opening a patent will cause a window to open ouside of the framed tutorial. To return to the tutorial simply click the back button in your browser's toolbar. You may notice that some patent numbers have a "D" before the number. This indicates that the patent is one of design as opposed to utility. Focus on the Abstracts, Current U.S. class and subclass numbers, and the claims. In fact, this is often a good time to go back to the Manual of Classification to see the context or a particular class/subclass. And finally, don't forget to look at the drawings. These are often a surefire way to determine your invention's uniqueness.


Patent searching is an iterative task.
To do a good search you must determine how your invention works, NOT how you will use your invention. For example, an improvement on an automobile switch will be found with switches--not with automobiles. Why? Because the invention is a switch, not an automobile.
When you don't find similar patents--try again. A good patent search will take many hours.
It is very difficult to prove a negative.
Patents are issued for new, original, non-obvious technologies. If your invention is truly original you won't find it already patented. However, you should be able to find related solutions.
Note: Just because you won't find any similar patents doesn't mean they aren't there. Examine your invention again--how does it REALLY work.
Patent language is difficult.
Patents describe a new technology so that it can be protected by a legal document. This means that patents consist of three types of language:

  • legal
  • technical
  • merely descriptive

The most difficult language is "merely descriptive." Why? Because new original technologies do not have accepted keywords, as a result the invention is described. For example, the phrase "Four rectangular uprights supporting a planar surface" describes a table. See what I mean?
Lawyers serve a purpose.
The best advice is to see a patent attorney once you have diligently searched the patent files and have determined to the best of your ability that your invention idea is:

  • new
  • patentable
  • marketable

Good luck. You may call +1 858 699 6015 or contact Integrity Intellectual Property for additional help using the patent files. 



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For new and inexperienced inventors, several really nice websites offer a great start. One first place to visit is the USPTO which dedicates significant resources to new inventors. The first place to start in most cases is the PTO search page. Another good privately run website is Ask the Inventors. Barbara and Mary have many nice pointers to save you from falling into traps. Edison Nation is a fun place with an active forum which can help many inventors help each other. Patent Attorney, Patent law A Few Good Sites
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