Anatomy of a patent

A patent looks like a block of legal text. It is in fact an orderly object, made of parts that each have a job and a rule that calls for them. Here we go through them one by one, on an example you can look at: a telescope.

For each part you find three things: what it is for, which rule requires it, and how it looks in the example. The rules quoted are those of the European Patent Convention (EPC) and its Implementing Regulations, with the Italian ones alongside where useful. The sources are listed at the end of the guide.

Example invention in two lines

The telescope in the example has an actuator that turns about an axis offset from the secondary mirror. A wide movement of the actuator then produces a small change in focus, and focusing becomes finer.

Six parts are involved: truss (10), secondary mirror (26), hexapod (28), top ring (42), actuator (44) and blackened bolts (50).

Front page and title

What it is for. It identifies the application: who files it, when, under which title. The title says what it is about, so that anyone searching can find it.

The rule. The title must clearly and concisely state the technical designation of the invention and exclude all fancy names (Rule 41(2)(b) EPC). The Italian Industrial Property Code also asks for a title that corresponds to the subject of the invention (Art. 51, paragraph 2).

In the example.

FieldValue
TitleTelescope with an offset-axis actuator
NatureDidactic example, imaginary invention
ApplicantNone: the document is not a real application

Note that the title is technical. It does not say "Revolutionary telescope" and it is not a trade mark.

Technical field

What it is for. It places the invention in its sector, in one sentence. The reader sees at once where it sits.

The rule. The description must specify the technical field to which the invention relates (Rule 42(1)(a) EPC; for Italy, Art. 21, paragraph 3, letter a) of Ministerial Decree 33/2010).

In the example.

The present invention relates to a telescope and, in particular, to focusing by means of an actuator acting on the hexapod of the secondary mirror.

Background art

What it is for. It tells what is already known, as far as the applicant knows, and where the invention starts from. It is the ground on which novelty is measured.

The rule. The description indicates the background art useful for understanding the invention, for drawing up the search report and for examination, and preferably cites the documents reflecting it (Rule 42(1)(b) EPC; Art. 21, paragraph 3, letter b) of Ministerial Decree 33/2010).

In the example.

In telescopes the focus depends on the position of the secondary mirror (26) along the optical axis, which the mirror holds thanks to the hexapod (28). To bring the image into focus, the useful stroke of the hexapod is lengthened or shortened with an actuator (44), carried by the top ring (42). In known solutions the actuator turns about the optical axis of the secondary mirror.

In a real application the documents would be cited here, with their publication numbers. In the example we cite none, because we do not want to attribute to anyone a text they did not write.

Technical problem

What it is for. It says what does not work in the background art, in technical terms. The problem guides everything else: the claims solve it, the description explains it.

The rule. The invention must be disclosed so that the technical problem, even if not expressly stated as such, and its solution can be understood. Any advantageous effects over the background art are stated (Rule 42(1)(c) EPC). There is no need to present the invention in "problem and solution" form, and known products or processes must not be disparaged (European Patent Office (EPO) Guidelines, F-II, 4.5).

In the example.

With the actuator turning about the optical axis of the secondary mirror, a small rotation of the actuator moves the focus a great deal. Fine focusing is therefore difficult. The technical problem is to allow finer focusing through the useful stroke of the hexapod without adding parts to the telescope.

Summary and solution

What it is for. It presents the solution briefly, in the same words as the claims. It is the summary the reader looks for after the problem.

The rule. It is part of the disclosure of the invention required by Rule 42(1)(c) EPC. If the claims change during the procedure, this part has to be brought back into line too (EPO Guidelines, F-II, 4.2).

In the example.

According to the invention, the actuator (44) turns about an axis of rotation offset from the optical axis of the secondary mirror (26). A wide rotation of the actuator (44) thus produces a small change in the useful stroke of the hexapod (28).

Brief description of the figures

What it is for. It lists the sheets of drawings and says what each one shows. It is the index of the drawings.

The rule. The description briefly describes the figures (Rule 42(1)(d) EPC). Figures are numbered consecutively in Arabic numerals, preceded by the abbreviation "FIG" (EPO Guidelines, A-IX, 5.2).

In the example.

FIG. 1 is a partial plan view of the telescope. FIG. 2 is an enlarged view of the area of the actuator (44).

Detailed description

What it is for. It explains the invention with the drawing at hand, part by part, so that a person skilled in the art can carry it out.

The rule. The invention must be disclosed in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art (Art. 83 EPC; Art. 51, paragraph 2, of the Italian Code). When an element of the drawing is cited, both name and number are written: not "26 is connected to 28" but "secondary mirror 26 is connected to hexapod 28" (EPO Guidelines, F-II, 4.7). Every numeral must be explained, and those used in the description and claims appear in the drawings (F-II, 4.8; A-IX, 7.5.4).

In the example.

With reference to FIG. 1, the telescope comprises a truss (10) carrying a top ring (42). The top ring (42) is fixed to the truss (10) by two blackened bolts (50) and holds a secondary mirror (26). A hexapod (28) is connected to the secondary mirror (26). The secondary mirror (26) is centred on the optical axis, and its position along the axis depends on the useful stroke of the hexapod (28).

With reference to FIG. 2, the top ring (42) carries an actuator (44). The actuator (44) engages the hexapod (28) and defines its useful stroke. The actuator (44) turns about an axis of rotation that does not coincide with the optical axis of the secondary mirror (26) but is offset from it. When the actuator (44) is turned through a given angle, the secondary mirror (26) moves along the optical axis by a shorter stretch than it would with a concentric axis. The useful stroke changes by a little and the focus is adjusted with more precision.

Embodiments

What it is for. It shows at least one concrete way of making the invention, with examples and variants. It supports the claims, in particular the dependent ones.

The rule. The description describes in detail at least one way of carrying out the claimed invention, using examples where appropriate and referring to the drawings (Rule 42(1)(e) EPC; Art. 21, paragraph 3, letter e) of Ministerial Decree 33/2010).

In the example.

In one embodiment, the distance between the axis of rotation of the actuator (44) and the optical axis of the secondary mirror (26) is between 10% and 30% of the outer radius of the hexapod (28). In another, the actuator (44) turns within an arc of between 20 and 60 degrees. The top ring (42) may be fixed to the truss (10) by two or more blackened bolts (50).

The figures are invented, like the whole example. In a real patent, every number that appears in a claim must have its basis here.

Claims

What they are for. They say what is protected. The rest of the patent explains, the claims delimit. The extent of protection is determined by the claims, and the description and drawings are used to interpret them (Art. 69, paragraph 1, EPC; Art. 52, paragraph 2, of the Italian Code).

The rule. The claims define the matter for which protection is sought, clearly and concisely, and are supported by the description (Art. 84 EPC). They are written in terms of the technical features of the invention. Where appropriate they have two parts: a preamble with the designation of the subject-matter and the features already known, then a characterising portion beginning with "characterised in that" and stating the features for which protection is sought (Rule 43(1) EPC). Dependent claims refer to another claim and add features (Rule 43(4)). They are numbered in Arabic numerals (Rule 43(5)).

The numbers in brackets. When the application contains drawings with reference numerals, the technical features are followed by the matching numeral, in brackets, if this makes the claim easier to understand. The numerals do not limit the claim: they only help in reading it (Rule 43(7) EPC; for Italy, Art. 21, paragraph 4, letter c) of Ministerial Decree 33/2010, which says the same). In two-part claims the numerals go in both the preamble and the characterising portion (EPO Guidelines, F-IV, 4.18).

Claim set of the example

In claim 1 every feature carries its numeral. The preamble holds what is already known, the characterising portion what the example adds.

  1. A telescope comprising:

    • a truss (10);
    • a secondary mirror (26) centred on its own optical axis;
    • a hexapod (28) connected to the secondary mirror (26);
    • a top ring (42), carried by the truss (10) and holding the secondary mirror (26); and
    • an actuator (44), carried by the top ring (42) and engaging the hexapod (28) to define a useful stroke thereof;

    characterised in that the actuator (44) is rotatable about an axis of rotation offset from the optical axis of the secondary mirror (26).

  1. The telescope according to claim 1, wherein the distance between the axis of rotation of the actuator (44) and the optical axis of the secondary mirror (26) is between 10% and 30% of the outer radius of the hexapod (28).
  2. The telescope according to claim 1 or 2, wherein the top ring (42) is fixed to the truss (10) by at least two blackened bolts (50).
  3. The telescope according to any one of the preceding claims, wherein the actuator (44) is rotatable within an arc of rotation of between 20 and 60 degrees.

How to read it:

  • Claim 1 is independent, in the two-part form.
  • Claims 2, 3 and 4 are dependent: each refers back to the preceding ones at the start and adds one feature.
  • The bracket next to "actuator" does not change what is protected: it helps the reader find the element on the drawing.

Drawings

What they are for. They show what the words describe. An application contains drawings if the description or the claims refer to them (Art. 78, paragraph 1, letter d), EPC). For the Italian patent for invention, drawings are annexed when they are needed to understand the invention (Art. 51, paragraph 1, of the Code).

The rules of form. Since 1 February 2023 the detailed rules on European drawings are no longer in a rule of the EPC: Rule 46 was deleted, and the presentation requirements are set by the President of the EPO under Rule 49(2). The Guidelines (Part A, Chapter IX) summarise the practice. In short:

  • figures are numbered in consecutive Arabic numerals with the abbreviation "FIG";
  • numbers and reference letters are simple and clear, with no brackets, circles or inverted commas (A-IX, 7.5);
  • a numeral used in the description or claims appears in the drawing, and vice versa, and the same element has the same numeral throughout (A-IX, 7.5.4 and 7.5.5);
  • the drawings contain no text, except a few indispensable words (A-IX, 8);
  • the scale must allow reproduction reduced to two thirds without losing detail (A-IX, 7.4).

In the example. Two figures: FIG. 1 with truss (10), top ring (42), secondary mirror (26) and hexapod (28); FIG. 2 with the enlargement of actuator (44) and blackened bolts (50). All six numerals used in the text, and only those.

Abstract

What it is for. It is a short card, useful to someone searching who must decide whether to read the rest. It cannot be used to interpret the extent of protection (EPO Guidelines, F-II, 2.1).

The rule. The abstract gives the title, indicates the technical field and concisely summarises the problem, the gist of the solution and the principal use. It contains no statements on the value of the invention. It preferably does not exceed 150 words. Each essential feature illustrated in the accompanying figure is followed by a numeral in brackets (Rule 47 EPC).

In the example.

Telescope with an offset-axis actuator. The telescope comprises a truss (10), a top ring (42) holding a secondary mirror (26) with a hexapod (28), and an actuator (44) defining the useful stroke of the hexapod (28). The actuator (44) turns about an axis offset from the optical axis of the secondary mirror (26), so that a wide rotation of the actuator (44) produces a small change in the useful stroke. Focusing is finer. (Figure to be published: FIG. 2.)

Before writing yours

This page is general information, not legal advice: a real application should be reviewed by a patent attorney. In the app, the parts of this page correspond to the Drawings and Draft steps.

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. 84 EPC, Claims: https://www.epo.org/en/legal/epc/2020/a84.html (read on 2026-10-05)
  3. Art. 69 EPC, Extent of protection: https://www.epo.org/en/legal/epc/2020/a69.html (read on 2026-10-05)
  4. Rule 41 EPC, Request for grant: https://www.epo.org/en/legal/epc/2020/r41.html (read on 2026-10-05)
  5. Rule 42 EPC, Content of the description: https://www.epo.org/en/legal/epc/2020/r42.html (read on 2026-10-05)
  6. Rule 43 EPC, Form and content of claims: https://www.epo.org/en/legal/epc/2020/r43.html (read on 2026-10-05)
  7. Rule 46 EPC (deleted): https://www.epo.org/en/legal/epc/2020/r46.html (read on 2026-10-05)
  8. Rule 47 EPC, Form and content of the abstract: https://www.epo.org/en/legal/epc/2020/r47.html (read on 2026-10-05)
  9. Rule 49 EPC, Presentation of the application documents: https://www.epo.org/en/legal/epc/2020/r49.html (read on 2026-10-05)
  10. Index of the Guidelines, edition: https://www.epo.org/en/legal/guidelines-epc (read on 2026-10-05)
  11. F-II, 2.1 Purpose of the abstract: https://www.epo.org/en/legal/guidelines-epc/2026/f_ii_2_1.html (read on 2026-10-05)
  12. F-II, 4.2 Technical field: https://www.epo.org/en/legal/guidelines-epc/2026/f_ii_4_2.html (read on 2026-10-05)
  13. F-II, 4.5 Technical problem and its solution: https://www.epo.org/en/legal/guidelines-epc/2026/f_ii_4_5.html (read on 2026-10-05)
  14. F-II, 4.7 Reference in the description to drawings: https://www.epo.org/en/legal/guidelines-epc/2026/f_ii_4_7.html (read on 2026-10-05)
  15. F-II, 4.8 Reference signs: https://www.epo.org/en/legal/guidelines-epc/2026/f_ii_4_8.html (read on 2026-10-05)
  16. 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)
  17. A-IX, 5.2 Numbering of figures: https://www.epo.org/en/legal/guidelines-epc/2026/a_ix_5_2.html (read on 2026-10-05)
  18. A-IX, 7.4 Scale of drawings: https://www.epo.org/en/legal/guidelines-epc/2026/a_ix_7_4.html (read on 2026-10-05)
  19. A-IX, 7.5 and 7.5.4: https://www.epo.org/en/legal/guidelines-epc/2026/a_ix_7_5.html (read on 2026-10-05)
  20. A-IX, 8 Text matter on drawings: https://www.epo.org/en/legal/guidelines-epc/2026/a_ix_8.html (read on 2026-10-05)
  21. Italian IP Code (D.Lgs. 30/2005), art. 51 (Sufficient disclosure): https://www.normattiva.it/uri-res/N2Ls?urn:nir:stato:decreto.legislativo:2005-02-10;30~art51 (read on 2026-10-05)
  22. Italian IP Code (D.Lgs. 30/2005), art. 52 (Claims): https://www.normattiva.it/uri-res/N2Ls?urn:nir:stato:decreto.legislativo:2005-02-10;30~art52 (read on 2026-10-05)
  23. 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)