Classification Codes

In the next step, we need to look 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 the previous step. This takes us to Class 345 (Computer Graphics Processing and Selective Visual Display Systems) and Subclass 156 (Display Peripheral Interface Input Device) of the Manual of Classification.
    Screenshot of patent classification subheading "mouse" showing class and subclass numbers. 

  2. Now is the time to think about that plus sign that we saw in the Index of Classification. Remember to look at the subclasses before and after 156 for any closely related classifications.

    IMPORTANT! To do so you must scroll towards the top of the page and ensure that the drop down 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.
  3. Screenshot showing dropdown menu options for expansion level.

    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.
  4. 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.

  5. In our example, Cursor mark position control device has one dot, so we know that it is a more specifically defined classification within the subdivision of Display Peripheral Interface Input Devices. You'll notice that Photosensor encoder has four dots, which indicates that it is a more specifically defined subclass of Rotatable ball detector, which 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.

    Screenshot illustrating dots that show subclass specificity.

  6. At this point, you may find that the classifications in the selected list do not match your invention, so you will need to start your search again with a revised strategy—go back to your brainstorming list, or look again at the subheadings in the Index Search step. However, if at this point you can identify a classification that seems like a good match for your invention, you can proceed.
  7. Click on the subclass number that most closely matches your invention. In this case, we'll choose subclass 163Mouse.

Screenshot of subclass 163, "mouse."