Provisional specification

A provisional is often sold as a cheap way to “get a date”. It is - but only for what it actually describes.

In simple words

A first filing that describes the invention but need not contain claims. It secures a priority date, and a complete specification must follow within twelve months or the application is treated as abandoned.

Think of it as

A dated envelope. It protects what is inside it, and nothing else.

Why it matters

A provisional buys time and priority, which can be decisive. But priority attaches only to subject matter fairly disclosed in it. Anything you add in the complete specification gets the later date, and prior art published in between can be used against that added matter.

A simple example

Your provisional describes a sensor using an infrared emitter. Eleven months later you file a complete specification adding an ultrasonic version. A paper published in month six describing an ultrasonic version is prior art against that added part - though not against the infrared part.

Common mistake

Filing a two-page provisional and assuming it covers whatever the product becomes. It covers what it describes.

Where it comes from

Patents Act 1970 - sections 9 and 11; Patents Rules 2003, rule 13