Clarity – Making Your Patent Claims Crystal Clear

According to European Patent Office (EPO) rules

Even if your invention is new and inventive, your patent can still fail if your claims are unclear. Clarity is about making sure others can understand exactly what you are protecting.

What does clarity mean?

According to EPO laws and practice, claims must be:

Clear – no vague words or contradictions.
Concise – no unnecessary repetition.
Supported by the description – the claim should match what you actually teach in the patent.

Think of clarity as the map of your invention: if the map is fuzzy, no one can tell where your rights begin or end.

Common clarity challenges

Vague terms: Words like “thin”, “fast”, “efficient”, “improved” without numerical definition are unclear.
Relative terms: “High speed motor” → unclear unless “high” is defined by measurable values.
Functional language: “A device adapted to…” can be fine, but only if it is testable in practice.
Contradictions: If your claim says “copper rivets” but the description only talks about aluminium rivets, clarity is lost.
Undue breadth: Claiming more than what is described can make the scope unclear.

Pitfalls to avoid

Copy-pasting marketing terms: Words like “eco-friendly” or “user-friendly” don’t work in patents.
Over-complicated phrasing: Long sentences with multiple “wherein” clauses confuse both examiners and competitors.
Unclear boundaries: If it’s impossible to tell whether a competitor’s product falls under your claim, the claim is not clear.

Practical examples

Unclear: “A lightweight bicycle frame” → how light is lightweight?
Clear: “A bicycle frame weighing less than 8 kg.”
Unclear: “A detergent providing improved cleaning.”
Clear: “A detergent composition that removes at least 95% of wine stains in a 40°C wash.”

Key takeaway

Clarity is about precision. Your patent must tell others exactly what you own—no more, no less. Think like a scientist, not a marketer: define, measure, and specify.

Clear claims don’t just satisfy the EPO — they also make your patent stronger in court and easier to enforce.