[leros]

Patents cover specific processes. You can do the same thing with another process.

For example, there is a company that patented a dust bin fullness sensor. Their patent specifically says it uses an infrared range detector,alarms via a red strobe light, and is designed to be used for the process of detecting dust levels. You could build the same device with a different range detector, or a different alarm method, or for an application other than dust bin level detection and you would be fine.