A more thorough explanation:

Definition: Field of invention refers to the classification of patents into broad classes and narrow subclasses to aid in patent searches. It is also known as office classification or field of search.

Examples: For example, a patent for a new type of computer software may be classified under the broad class of "Information Processing" and the narrow subclass of "Software Applications." Another patent for a medical device may be classified under the broad class of "Medical Technology" and the narrow subclass of "Diagnostic Equipment."

Explanation: The examples illustrate how patents are sorted into different fields of invention based on their type and purpose. This helps patent examiners and researchers to easily search for relevant patents in a specific field and avoid duplication of existing inventions.