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Patent Classification Primer

Patent classification information tells you a lot about a patent including:

How Patents Are Organized

We are working on adding new information on how classification using the Cooperative Patent Classifications (CPC) works pending release of official classification procedures from the USPTO—EPO classification organization.

image of data archive

Classification information is a valuable tool in helping you understand what's "IN" a patent or patent application. If you understand the way patents are classified it makes looking for what you want less torture. It also lowers the odds that you'll miss important inventions before you spend a lot of money on developing a patent application or developing a product that infringes on someone else's patent. The research may still be torture but it won't be as bad as trying to find things without their classifications.

If your invention is really novel, searching for patents and looking for prior art will be hard, frustrating, and won't produce much. This is a GOOD THING.

Finding Patents Using The USPC

A Fingerprint of an Invention
Looking at classifications gives you a fingerprint of what an invention is and a list of all of its important parts. Patent pros know that understanding the content of the patent classification systems can give you an important edge in your patent and intellectual property activities.

The USPC covers eveything that was invented since George Washington signed the first patent in 1790. (That's why patent nerds use 1790 as a codeword for their projects.) The current US Patent Classfication system has over 150,000 classifications. The new and emerging Cooperative Patent Classification system due our in January 2013 promises to have over 200,000 classifications. Think of classes and subclasses as the modern version of a patent shoe — the specialized cabinets that were used to organize patent documents. (The photo of our favorite patent examiner in front of the shoes is below.)

Classification —What's "in" an Invention
The USPC is designed for organizing US patent documents (patent applications, patents, prior art technical and scientific material) into relatively small collections based on a common subject matter.

USPTO defines classes — major boundaries between one technology and another — and subclasses which delineate processes, structural features, and functional features of the subject matter in a class.

Subclasses are the smallest division of subject matter that USPTO uses to organize subject matter. Patents are only classified at the subclass level, not at the class level. It's done this way so that examiners have a very granular breakdown of what's in a patent. In the old days the patent documents were organized in "Shoes" that held patents about the same subject matter. Modern classification tries to keep things broken down into reasonable groups.

Classifying patents is hard work.
Despite sometimes getting a bad press over the quality of the patent classification, USPTO and the people who actually classify the patents, work very hard at a sometimes daunting task. And, they meticulously cross-reference all the content so you can slice and dice the classifications to find what you are looking for. (Really.)

What do the numbers mean?
The way USPTO represents the class and its subclasses is CLASS/SUBCLASS. So classes look like this: 368/10. Class 368 is HOROLOGY: TIME MEASURING SYSTEMS OR DEVICES. Subclass 10 covers inventions for COMBINED WITH DISPARATE DEVICE. This is patentspeak for a time measuring or time telling device that has some other gizmo that isn't part of the time telling stuff. More on this in a bit. (The titles are all capitals despite making them hard to read — a USPTO convention.)

Keep the collections manageable.
Since USPTO (and all the other national patent offices) handle inventions for just about everything you can imagine, they break the subclasses down into finer and finer groups so that the collections are manageable. Consider the 368/10 example. There are lots of different types of disparate devices that can be combined with a time measuring device. If you are a basketball fan, there's the timer that has a signal to indicate that the quarter is over. There are many different uses of internal clocks that control all kinds of industrial and consumer devices. There are watches that have thermometers and watches with GPS and other navigational devices (scary but true.) If you are really interested in how this process works, checkout USPTO's Classification Change Orders. The Change Orders provide a very interesting look at the evolution of technology by themselves. (Kind of patent nerdy but fun.)

So USPTO breaks the disparate devices into their own groups. These groups are "indented " under subclass 10. So basically it looks like this:

Class Subclass Class/Subclass Title
368 HOROLOGY: TIME MEASURING SYSTEMS OR DEVICES
10 COMBINED WITH DISPARATE DEVICE
11 .Ambient condition detector: (With environmental stuff like the thermometer)
12 .External alarm
13 .Telephone
14 .Navigational instrument: (A rescue-facilitating, preferably water resistant communicating wrist watch — US 8,059,491)

As the technology grows more complex or just grows, the USPTO and other patent offices split the subclasses up into reasonable groups to assist the examiners and the inventors in understanding what's "in" a patent. For the patent purists among us there is some additional deep dive information at the bottom of this page.

How Do I Use Classification Information?

You want to invent a device for telling time and communicating with headquarters during a crime spree but you want to know if your device is patentable. You're thinking that you want to invent a radio watch like that Yellow Fedora wearing detective wore, so you'd need to research patents with a watch with a radio (or a cellphone), and a clock, some buttons to make it work, a wrist band, and a wireless antenna device, to name some of the basics. Or maybe it's a radio that you wear on your wrist that also tells time. Where do you start looking?

Watches might be a good place to start.

radio watch with telephone

USPC Class 368 is Horology: Time Measuring Systems and Devices

The next stop is to move down to the subclasses under 368 Horology and see how Time Measuring Systems and Devices are broken down.

Then you start scrolling down the list until you hit subclass 10 (368/10 is it's official identification.) 368/10 is where you will find Time Measuring Systems and Devices Combined with Disparate Device. This is where "a timepiece housed with or attached to an additional device which has a function other than that of keeping time and which does not serve to perfect the timepiece" is found.

We're getting there. So what kind of disparate device? Under 368/10 you have four choices:

Subclass Class/Subclass Title
368/11 Ambient condition detector — something that measures or senses the quality of the environment (the temperature for example)
368/12 External alarm — something that gives an audible or visual warning and is not an integral part of the timepiece.
368/13 Telephone — the disparate device is a telephone.
368/14 Navigational Instrument — an instrument used to manage or direct the course of a vehicle, GPS on your watch.

In USPTO speak, these subclasses are "indented" under 368/10. As the technology becomes more granular the subclasses are indented more. So here you are:

Class # Subclass Class/Subclass Title
368 HOROLOGY: TIME MEASURING SYSTEMS OR DEVICES
368/10 Devices Combined with Disparate Device
.368/13 Where the disparate device is a telephone.

Subclass 13 is indented under subclass 10 because it defines the type of disparate device that is combined with the time measuring system or device. (This gets easier as you do it. You find what you are looking for by moving down and to the right of the class tree.) Another trick is that the more complex inventions are at the top of the class tree and the "miscellaneous" stuff is toward the bottom.

Back to Building the New Radio Watch
The first place to look for patents like the Yellow Fedora wearing detective wore is Class 368/13.

There Can Be Only One OR
In USPTO speak this is called the OR Classification for Original Classification. This is the classification that describes the most important invention information — the technical and scientific information disclosed in the patent's claims that is new and non-obvious. The OR is based only on the claimed disclosure (forgetting for a moment the classification dictum that "claims are to be read in light of the full disclosure"). A patent can only have ONE Original (OR) classification. This is the classification that appears first on the list of classification. On the printed patent this classification appears in BOLD

Once the primary invention information is determined, the next step is to see what else is embodied in the patent. Embodied is patent speak for included, integrated, part of, incorporated in the patent. Patent pros also use the word taught because a patent is supposed to teach someone ordinarily skilled in the art how to make the invention but we digress. So the classifications that appear after the first BOLD classification on a patent are the cross-reference or XR patent classifications. These describe the other inventive elements in a patent.

So now that you have your time measuring device that has a disparate device that is a phone (head spinning yet?), you need to consider all the other facets of the invention. What it's housed in. If the invention has housings, the patent would have an XR classification on the patent indicating the class/subclass for that aspect of the invention. If the invention is the housing, the housing classification will be the OR.

Patents can have many cross-reference XRs. The classifiers and patent examiners add as many classifications that are needed to help researchers understand all of the features embodied (working on our patent vocabulary here) in a patent. (Most have one or two XRs. Some have many.) Mandatory classifications pertaining to the claims are required, and discretionary classifications pertaining to the remainder of the disclosed information in a patent (the stuff in the description or the abstract or the drawings) may be assigned at the discretion of the examiner to aid in prior art searches. The mandatory classifications provide very useful information on the components and complexity of a patent, but USPTO chooses to create a giant blob of patent classifications that doesn't distinguish between mandatory and discretionary classifications. (Patent cognoscente would love to have the breakdown. If you would like one, let us know one of our patent analysts can work one up for you.)

The XR classifications are added for all the other elements of the invention described in a patent. Class 224 defines package and article carriers, how things are adapted to be supported on a person or an object. Class 224/165 describes the watch attaching means extending circumferentially around the wrist supporting a different article. Class 224/165 is used for a carrier where in another article is also carried by the attaching means (patent speak for the case and the band, not just a band.)

Then you might need to look and see if you need to add an antenna to the mix. The antenna would have its own XRs.

Confronting Convergence with a Class Mashup

Classifications come in handy when you are trying to figure out if science and technology are converging or if you are looking for patents that have all of the components of your radio watch (or watch radio) above. Consider all the items embodied in a smartphone. Or consider the smoke detecting cellphone. There are also situations where USPTO makes a call on what the OR classification is. It's done in a very systematic way but it's also a call —it is a phone, it is primarily a camera, is it a computer? The Class Mashup helps you find the patents with the exact group of classes you are looking for.

The Class Mashup
Way Better Patents™ solves the problem by letting you create your own very specific patent classification mashup. You can pick an OR that defines what you think the major content of the invention that you are looking for is and then select a group of XR classifications that define the add-in features and then do a search. The results that come back from a Class Mashup search will be the patents that match the patent fingerprint you are looking for. This can help you figure out how other inventors have put these features together as well as if your combination is unique, novel, and non-obvious.

The Class Timeline
Every patent has a classification. The Class Timeline lets you see how far back the patents classified in a particular subclass go back over time. You may think something is new but there may be older inventions (and sometimes very old inventions) that are out there in an area you are interested. The Class Timeline organizes all of the patents in a class/subclass by year. This gives you a quick visual on how far back the inventions go, which years saw a lot of inventions and which didn't which gives you clues on when certain technologies took off. Try it — it's in the blue tool bar at the top of the tool pages.

A Bit of Classification Geekery

Box Notes

Classification Box Notes are a bit of patent geekery known by patent analysts and researchers but generally not known by mere mortals that seek to find patents and prior art. A box note is an innocuous looking phrase at the beginning of the definition of a patent classification that says, "this is a an integral part of that" — "Class 600 is an integral part of Class 128". The US Patent Classification System (USPC) uses this convention when the number of patent assigned to a particular class explodes and becomes unmanageable. USPTO creates another class and puts the new stuff there. The box note basically informs the reader that if you are looking for prior art in this class, or within a certain class/subclass pair, that the rest of the patents and patent applications you need to look at can be found in another class. To use the Box Note effectively you also need to understand the concept of the indent within the USPC so you can understand exactly where the classes converge.

You'll find box notes in several key classes that have seen very large growth like Surgery which includes Class 128 plus 600, 601, 602, 604, 606 and 607; or Drug, Bio-Affecting and Body Treating Compositions which is covered by 424 and 514 Class 514 is an integral part of Class 424. It incorporates all the definitions and rules as to subject matter of Class 424.; or Organic Chemistry where there are many permutations.

Accounting for box notes can change the patent count calculus. When you look at the USPTO E-Gazette, it reports each class separately. There is also no guarantee that all of the art classified in one of the classes described in a box note is going to wind up in the same Group Art Unit, the group of patent examiners responsible for examining patent applications containing a particular classification. Injecting this bit of patent geekery into the box scores adds a level of intellectual vertigo that is contrary to our desire to make patents easier to understand. So we made a command decision not to torture our users with it. (We do includes this geekery in our custom patent analytics.) As a rule, we don't adjust USPTO's numbers to account for the impact of box notes when creating our score cards and boxscores.

The acetylsalicylic acid (aspirin) can be found in Class 560/143.

Deep Dive on Patent Classification Systems

USPTO and other national patent offices use their classification systems to organize patents so that researchers can find patents based on what the invention is about. They also use the classification assigned to a patent application to determine which group of patent examiners will be responsible for prosecuting the patent. And they harmonize the classifications so that you can look for patents globally.

The two primary classification systems are the US Patent Classification system (USPC) and the International Patent Classification System (IPC) which is managed by the World Intellectual Property Organization (WIPO).

There are other classifications systems like ECLA, the European Classification System, managed by the European Patent Office, which is an extension of the IPC; and DWPI, the Derwent World Patents Index; and a host of specialized classification schemes based on specific industries and subject matter. In short, there are lots of ways to slice and dice the content contained in a patent.

To add to the fun, the USPTO, which still grants the majority of patents in the world, and EPO have announced the Cooperative Patent Classification Project, an effort to harmonize (patent speak for coordinate and integrate) a classification scheme for inventions that will be used by both offices in the search and examination of patent applications. To say this is ambitious is an understatement.

Classification information is a valuable tool in helping you understand what's "in" a patent or patent application.If you understand how to use it, it will give you an edge. If you need a patent classification guru, — let us know.

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