Writing the claims

The claims are the part of a patent that matters most. Everything else prepares and explains them. Throughout this chapter we use the telescope from the didactic example on the page "Anatomy of a patent": an imaginary invention, with an actuator (44) that turns about an axis offset from the secondary mirror (26).

What a claim protects

A claim draws a boundary. Inside the boundary is what nobody else may do without the owner's permission. Outside it, everyone is free.

The European Patent Convention (EPC) says that the extent of protection is determined by the claims, and that the description and drawings are used to interpret them (Art. 69, paragraph 1). The Italian Industrial Property Code (the "Code") takes the same approach (Art. 52, paragraph 2). This is why every word counts: a badly written claim can leave out exactly what you wanted to protect.

In our example, claim 1 does not protect "a telescope with a nice focus". It protects a telescope with a truss (10), a secondary mirror (26), a hexapod (28), a top ring (42) and an actuator (44) that turns about an offset axis. What lies outside this precise description is not covered by that claim.

Independent and dependent claims

The independent claim states the essential features of the invention and stands on its own. It may be followed by claims on particular embodiments (Rule 43(3) EPC).

The dependent claim refers to another claim, usually at the start, and then adds features (Rule 43(4)). It contains all the features of the claim it refers to. That is why it is always narrower.

In the example:

  • claim 1 is independent;
  • claim 2 adds that the distance between the two axes is between 10% and 30% of the outer radius of the hexapod (28);
  • claim 3 adds that the top ring (42) is fixed to the truss (10) by at least two blackened bolts (50).

What are dependent claims for? They are a ladder of fallback positions. If one day claim 1 turned out to be too broad compared with what already exists, claim 2 or 3 offers narrower ground to stand on. The European Patent Office (EPO) Guidelines ask that the number of claims be reasonable and that what is already claimed not be needlessly repeated (F-IV, 5).

Categories: product, process, use, apparatus

The EPC speaks of four categories: product, process, apparatus and use (Rule 43(2)). The Guidelines reduce them to two kinds of claim: those to a physical entity (product, apparatus) and those to an activity (process, use) (F-IV, 3.1).

With the telescope:

  • an apparatus claim: "A telescope comprising…", the one we have already read;
  • a process claim: "A method of focusing a telescope, comprising turning the actuator (44) about an offset axis…".

This second one is not in the claim set of the example: it is only an illustration. The choice of category changes what you can stop others from doing. Someone who sells telescopes with the offset actuator is covered by the apparatus claim. Someone who focuses telescopes in an observatory is covered by the process claim. Another independent claim in the same category is allowed only in specific cases, for example several interrelated products or alternative solutions to one problem (Rule 43(2)).

Two-part form

Rule 43(1) EPC says that, where appropriate, the claim has two parts:

  1. a preamble with the designation of the subject-matter and the necessary features that, in combination, already form part of the prior art;
  2. a characterising portion, beginning with "characterised in that", with the features for which protection is sought in combination with those of the preamble.

In claim 1, the preamble lists truss (10), secondary mirror (26), hexapod (28), top ring (42) and actuator (44): everything a telescope with focusing already has. The characterising portion holds the one novelty of the example: the offset axis of rotation.

The form is used "where appropriate". The Guidelines say it can be artificial, for example when the invention lies in a combination of known elements of equal status, or when a complex system changes at several points (F-IV, 2.3). In the preamble it is enough to cite the known features that are needed: if the invention concerns only the actuator, there is no need to list the guide scope (70) as well (F-IV, 2.2). The Italian implementing regulation (Ministerial Decree 33/2010, Art. 21) does not prescribe this form.

Clarity, conciseness and support

Article 84 EPC asks for three things: the claims must be clear, concise and supported by the description. The Italian implementing regulation says the same (Ministerial Decree 33/2010, Art. 21, paragraph 4).

  • Clarity. The reader must understand what is covered without undue effort, and the claim leaves no doubt about its category (F-IV, 4.1).
  • Conciseness. No repetition: what repeats is written as a dependent claim (F-IV, 5).
  • Support. Every claim must have a basis in the description, and its scope cannot exceed what the description and drawings justify (F-IV, 6.1).

In the example, the "10% to 30%" of claim 2 is supported because the same range appears in the embodiments.

Unity of invention

An application relates to one invention only, or to a group of inventions linked so as to form a single general inventive concept (Art. 82 EPC). The link is technical: the inventions must share one or more special technical features, meaning those that define the contribution over the prior art (Rule 44(1)).

If we added to the telescope application an independent claim on a rubber cable carrier (86), it would share no special feature with the offset actuator. It would be another invention, to be taken to a divisional application.

Reference numerals in brackets

If the application has drawings, the features of the claim are followed by the numeral from the drawing, in brackets, when this makes the claim easier to understand. The numerals do not limit the claim (Rule 43(7) EPC). Art. 21, paragraph 4, letter c) of Ministerial Decree 33/2010 says the same.

Two cautions, from the Guidelines (F-IV, 4.18):

  • in the two-part form the numerals go in both the preamble and the characterising portion;
  • no text is added inside the bracket: "actuator (44, offset)" creates doubt about what it limits.

Common mistakes

The result to be achieved. "A telescope with very precise focusing" describes a goal, not an object. Such claims are in general not allowed, especially if they amount to the problem to be solved (F-IV, 4.10). Write how it is achieved: the offset axis.

Relative terms. "A slightly offset actuator": slightly compared with what? Terms such as "thin", "wide", "strong" are potentially unclear, because their meaning changes with context (F-IV, 4.6). A range is better, as in claim 2.

Elements without antecedent. If the claim says "the useful stroke" without ever having introduced a useful stroke, the reader does not know what it refers to. Introduce each element with "a" or "an", then refer back with "the". This is good drafting practice, serving the clarity that Art. 84 requires.

Claims broader than what you described. If the description shows the actuator (44) only on an observatory telescope with a top ring, a claim to "any optical instrument" is broader than what you have taught. It risks lacking support (F-IV, 6.1) and not being sufficiently disclosed (Art. 83 EPC; F-IV, 4.22).

References to the description or the drawings. Except where absolutely necessary, a claim does not rely on references to the description or the drawings to define its technical features: expressions such as "as described in the description" or "as illustrated in figure 1" are to be avoided (Rule 43(6) EPC). The text of the claim must be enough on its own.

How claims meet the prior art

An invention is new if it does not form part of the state of the art, that is, everything made available to the public before the filing date (Art. 54, paragraphs 1 and 2, EPC; Art. 46 of the Italian Code). It involves an inventive step if, to the person skilled in the art, it is not obvious from the state of the art (Art. 56 EPC; Art. 48 of the Code).

In simple terms it reads like this. Take a prior document and compare it, feature by feature, with claim 1:

  • if the document contains all the features, including the offset axis, novelty is lacking;
  • if it contains everything except the offset axis, novelty is there. What remains to be seen is whether the offset axis, with the problem it solves, would have been obvious to an expert.

For this the Guidelines use a three-step method: identify the closest prior art, formulate the objective technical problem, assess whether the solution would have been obvious (G-VII, 5). Here claim 2 and the other dependent claims become useful: if claim 1 does not hold, the 10% to 30% distance or the 20 to 60 degree arc can make the difference.

No claim, however well written, guarantees a grant on its own. The outcome depends on what already exists and on how the office assesses it.

In practice

This chapter is general information, not legal advice: a real application should be reviewed by a patent attorney. In the app this is the Strategy step.

Sources

  1. Art. 83 EPC, Disclosure of the invention: https://www.epo.org/en/legal/epc/2020/a83.html (read on 2026-10-05)
  2. Art. 82 EPC, Unity of invention: https://www.epo.org/en/legal/epc/2020/a82.html (read on 2026-10-05)
  3. Art. 54 EPC, Novelty: https://www.epo.org/en/legal/epc/2020/a54.html (read on 2026-10-05)
  4. Art. 56 EPC, Inventive step: https://www.epo.org/en/legal/epc/2020/a56.html (read on 2026-10-05)
  5. Rule 43 EPC, Form and content of claims: https://www.epo.org/en/legal/epc/2020/r43.html (read on 2026-10-05)
  6. Rule 44 EPC, Unity of invention: https://www.epo.org/en/legal/epc/2020/r44.html (read on 2026-10-05)
  7. Index of the Guidelines, edition: https://www.epo.org/en/legal/guidelines-epc (read on 2026-10-05)
  8. F-IV, 2.2 Two-part form: https://www.epo.org/en/legal/guidelines-epc/2026/f_iv_2_2.html (read on 2026-10-05)
  9. F-IV, 2.3 Two-part form unsuitable: https://www.epo.org/en/legal/guidelines-epc/2026/f_iv_2_3.html (read on 2026-10-05)
  10. F-IV, 3.1 Categories: https://www.epo.org/en/legal/guidelines-epc/2026/f_iv_3_1.html (read on 2026-10-05)
  11. F-IV, 4.1 Clarity: https://www.epo.org/en/legal/guidelines-epc/2026/f_iv_4_1.html (read on 2026-10-05)
  12. F-IV, 4.6 Relative terms: https://www.epo.org/en/legal/guidelines-epc/2026/f_iv_4_6.html (read on 2026-10-05)
  13. F-IV, 4.10 Result to be achieved: https://www.epo.org/en/legal/guidelines-epc/2026/f_iv_4_10.html (read on 2026-10-05)
  14. F-IV, 4.18 Reference signs: https://www.epo.org/en/legal/guidelines-epc/2026/f_iv_4_18.html (read on 2026-10-05)
  15. F-IV, 4.22 Broad claims: https://www.epo.org/en/legal/guidelines-epc/2026/f_iv_4_22.html (read on 2026-10-05)
  16. F-IV, 5 Conciseness, number of claims: https://www.epo.org/en/legal/guidelines-epc/2026/f_iv_5.html (read on 2026-10-05)
  17. F-IV, 6.1 Support in description: https://www.epo.org/en/legal/guidelines-epc/2026/f_iv_6_1.html (read on 2026-10-05)
  18. G-VII, 5 Problem-solution approach: https://www.epo.org/en/legal/guidelines-epc/2026/g_vii_5.html (read on 2026-10-05)
  19. Italian IP Code (D.Lgs. 30/2005), art. 46 (Novelty), Normattiva: https://www.normattiva.it/uri-res/N2Ls?urn:nir:stato:decreto.legislativo:2005-02-10;30~art46 (read on 2026-10-05)
  20. Italian IP Code (D.Lgs. 30/2005), art. 48 (Inventive step): https://www.normattiva.it/uri-res/N2Ls?urn:nir:stato:decreto.legislativo:2005-02-10;30~art48 (read on 2026-10-05)
  21. Ministerial Decree 33 of 13 January 2010, art. 21 (Description and claims of the patent application): https://www.certifico.com/component/attachments/download/33912 (copia consolidata; ufficiale: https://www.normattiva.it/eli/id/2010/03/09/010G0044/ORIGINAL (read on 2026-10-05)