Patent Drawing in Leuven.

A patent drawing Leuven filing sits in a system with one unusual feature that changes how figures should be prepared: Belgium grants patents without substantive examination. No Belgian examiner will tell you that a view is missing, that a numeral is unmatched, or that your hatching has swallowed a reference sign. The defect simply travels into the granted patent and waits to be argued about in Brussels. For a city whose filing profile is dominated by imec-grade nanoelectronics and KU Leuven spin-outs, where the figures often carry more technical weight than the prose, that is a meaningful risk to leave unmanaged.

Where a patent drawing Leuven application is actually filed

Belgium’s national office is the Belgian Office for Intellectual Property — the Office de la Propriété Intellectuelle / Dienst voor de Intellectuele Eigendom, usually shortened to OPRI or DIE. It is not a standalone agency. It sits inside the Federal Public Service Economy in Brussels, which is also where the filing and registration functions live. There is no separate patent counter in Leuven or in Flemish Brabant, so a Leuven applicant files centrally, electronically in almost every case. A patent drawing Leuven project therefore has no local filing desk to ask about formalities, which is one reason the sheets tend to get checked late.

Language is a real consideration rather than a formality. Belgium’s filing languages follow its language regions, and Leuven is in Dutch-speaking Flanders, so a Belgian national application from a Leuven applicant is normally filed in Dutch. That matters for the drawings because any text matter on a sheet is text that will have to survive translation if the family later moves to the European Patent Office in English. Keeping sheet annotation to the minimum the rules allow is cheaper than re-lettering a set later.

The other route into Belgium does not involve OPRI at all. A European patent granted by the EPO can be given effect in Belgium, and since Belgium dropped its translation requirements that route is administratively light. Many Leuven applicants — certainly most of the ones with international portfolios — reach Belgium that way rather than through a Belgian national filing.

Article 14: the drawing formalities OPRI actually applies

Belgian drawing requirements are not in the Code of Economic Law itself. They sit in the implementing decree: the Royal Decree of 2 December 1986 on the application for patents and the granting and maintenance of patents. Article 14 is the drawing article, and it is specific:

• Useful surface of 26.2 cm × 17 cm on A4 sheets of 29.7 × 21 cm. The paper must be flexible, strong, white, smooth, matte and durable.
• Margins of 2.5 cm at the top, 2.5 cm on the left, 1.5 cm on the right and 1 cm at the bottom. Sheets are used in portrait orientation, short sides top and bottom.
• Black, sufficiently dense and dark, uniformly thick and well-defined lines, without colours or washes. Hatching used for cross-sections must not obscure reference signs.
• Figures and letters at least 0.3 cm high, in the Latin alphabet, with Greek letters where customary.
• Views numbered consecutively in Arabic numerals, independently of the sheet numbering — so Figure 7 can sit on sheet 3 without any difficulty.
• No text on the drawings beyond short indications that are genuinely indispensable, of the “water”, “steam”, “open”, “closed” variety. Circuit and process diagrams may carry essential keywords only.
• Reference signs may only be used if they appear in the description and claims, and the same sign must be used for the same element throughout the application.

Anyone who has prepared sheets to European standards will recognise most of this, because the Belgian decree was drafted alongside the EPC formalities. The margins are identical to those the PCT uses.

The practical effect is that a competent EPO-standard set generally satisfies Article 14 without modification, while a set prepared only to US practice may not — the 0.3 cm character height, for instance, is slightly below the 0.32 cm the USPTO requires, so that direction is safe, but the no-colour rule is absolute here in a way it no longer is at the EPO. A patent drawing Leuven set built for both offices should therefore default to the stricter of the two rules at every point of conflict.

Why no Belgian examiner will fix your figures

This is the feature of Belgian practice that should change how a Leuven figure set is prepared, and it is routinely misunderstood.

OPRI does not examine patentability. There is no request for substantive examination in the Belgian system because the step does not exist. A novelty search is carried out — the European Patent Office prepares a search report with a written opinion on patentability, on payment of the relevant fee — but that written opinion is not binding on OPRI and does not constitute an examination of the invention. The patent is granted irrespective of what the search found, generally around 18 months after the filing date.

Compare that with a US utility application, where an examiner reads the claims against the sheets and will issue a requirement for additional illustration if a claimed feature is not shown. In Belgium nobody performs that check on your behalf. A missing view, a numeral that appears on a sheet but nowhere in the description, or a cross-hatch pattern that has buried a reference sign will all pass straight through to grant.

They do not disappear. They surface years later, when the patent is asserted and the defendant goes looking for a sufficiency or added-matter argument — and the figures are part of the disclosure that is read to decide what the application actually taught. Our work on patent drawings as prior art covers how figures get read back against a patent long after filing. For a Belgian national patent the pre-filing sweep is the only quality gate in the process, which is a reason to take it seriously rather than a reason to skip it. In a patent drawing Leuven engagement that sweep is the work, not an add-on to it.

There is no Belgian PCT national phase

If your Leuven filing programme runs through the PCT, this determines which drawing standard governs, and getting it wrong wastes a national-phase deadline.

Belgium cannot be entered nationally from a PCT application. OPRI ceased to act as a PCT receiving Office with effect from 1 April 2018, and Belgium is one of the group of states — alongside Cyprus, France, Greece, Ireland, Italy, Latvia, Monaco, Malta, the Netherlands and Slovenia — that have closed the national route for international applications. For a PCT family, protection in Belgium is obtained through the EPO regional phase and nothing else.

The consequence for the sheets is direct. The governing formalities for the overwhelming majority of Leuven patent families are the EPO’s, not Article 14’s, because the application is going to be examined in Munich or The Hague rather than registered in Brussels. Build to EPO standards and the Belgian national requirements are satisfied automatically if you ever do file nationally. Build only to Article 14 and you have optimised for the route you are least likely to use. We scope every patent drawing Leuven brief around the route the family is actually taking, for that reason.

Both still differ from the international phase. PCT Rule 11.13(a) requires black lines without colourings, so a colour figure that the EPO will now accept electronically is not acceptable on an international application. Variants are worth planning deliberately at the outset; discovering the conflict at regional-phase entry is the expensive version.

Where Leuven patent disputes are heard

Belgium concentrates patent litigation in a single venue, which makes the forum question unusually simple to answer and unusually important to plan for.

• Brussels Enterprise Court — the Ondernemingsrechtbank Brussel / Tribunal de l’entreprise de Bruxelles holds exclusive jurisdiction for the whole of Belgian territory over patent and supplementary protection certificate disputes. A Leuven company suing on a Belgian patent does not litigate in Leuven; it litigates in Brussels, and so does everyone else in the country.
• Brussels Court of Appeal — the appellate venue for those decisions.
• Unified Patent Court, Brussels local division — Belgium participates in the UPC, which opened on 1 June 2023. The Brussels local division sits in the Federal Public Service Economy building at Rue du Progrès 50, 1210 Brussels, and is the only division in the system where proceedings can be conducted in four languages: Dutch, German, French and English.

That four-language capability is a genuine strategic asset for a Flemish applicant, because it allows a Dutch-language case to be run locally without the translation overhead most divisions impose. For unitary patents the UPC is exclusively competent; during the transitional period national courts still share jurisdiction over classical European patents that have not been opted out, which means a Leuven portfolio can face both forums at once. In either court the drawings are read as part of the disclosure, so figure quality is a litigation input and not only a filing formality — the reason a patent drawing Leuven brief is worth treating as enforcement preparation rather than paperwork.

What Leuven’s deep-tech base demands from a figure set

Leuven files a narrow and demanding mix, and the industry profile shapes what good drawings look like here more than in most cities of its size.

• Nanoelectronics and semiconductors. imec is headquartered in Leuven, with several thousand researchers working on system scaling, silicon photonics, advanced sensing and beyond-5G communications, and a patent portfolio to match. Semiconductor disclosures live or die on cross-sectional stack views where layer order and relative thickness are the invention, and on process-flow sequences shown as a series of related figures. Hatching discipline is not cosmetic in this work — Article 14’s rule that hatching must not obscure reference signs is exactly the rule a dense layer stack breaches.
• University spin-outs. KU Leuven, founded in 1425, and its technology transfer office KU Leuven Research & Development generate a steady stream of filings, often arriving as research figures built for a journal rather than for a patent office. Converting a publication figure into a compliant sheet means stripping the annotation, re-lettering to 0.3 cm, and adding the views the claims will need.
• Additive manufacturing and medical devices. Materialise is headquartered on Technologielaan in Leuven, in 3D printing and medical additive manufacturing. These filings combine geometry that is genuinely three-dimensional with regulatory-grade detail, which usually means more sectional and partial views than an applicant’s first draft contains.
• Brewing and process engineering. AB InBev has its global headquarters at Brouwerijplein in Leuven. Process, packaging and plant filings mean flow diagrams and schematics, which is precisely the category where Article 14 permits essential keywords and nothing more.

Across all four, the recurring failure is the same: a figure set that was produced for a different audience — an examiner’s monitor, a journal reviewer, a design review — and never re-tested against the claims. Deciding the view list before anyone opens a CAD package remains the cheapest intervention available, and it is where a patent drawing Leuven project earns most of its value. Our guide to patent drawing sectional views covers the hatching conventions this work depends on.

Rule 46 EPC is gone — cite the right European authority

Because most Leuven families reach Belgium through the EPO, the European citation matters more here than the Belgian one. If a drawing provider quotes you “Rule 46 EPC compliance”, they are quoting a rule that no longer exists.

Rule 46 EPC was deleted with effect from 1 February 2023, together with Rule 49(3) to (12) EPC, as part of the EPO’s digital-transformation package. The presentation requirements moved into a Decision of the President published in the Official Journal, so the Office can adjust them without amending the Implementing Regulations. The working text to rely on now is the EPO Guidelines for Examination, Part A, Chapter IX.

Two points from the Guidelines bear directly on Leuven work. Text matter on drawings is limited to a single word or a few words where absolutely indispensable — “section on AB” is fine, a block of Dutch annotation carried over from an internal design document is not — and remaining keywords must be placed so they can be replaced by translations without disturbing the line work.

The second point is colour. Since 1 October 2025 the EPO accepts electronically filed drawings in colour or greyscale, provided they are contrast-rich and legible at 300 dpi. That is a real change for semiconductor and biological figures, and it is also a trap: Article 14 still forbids colour for a Belgian national filing, and PCT Rule 11.13(a) still requires black lines. Three routes, three answers on the same question — which is why a patent drawing Leuven set is usually delivered as variants rather than as one file. Our guide to EPO Guidelines A-IX sets out the detail.

Seven checks before you file in Leuven

1. Decide the route first — Belgian national filing with OPRI, or EPO regional phase. There is no Belgian PCT national phase, so for a PCT family the EPO standard governs.
2. Verify A4 geometry, a 26.2 × 17 cm useful surface and margins of 2.5 / 2.5 / 1.5 / 1 cm on every sheet, including continuation sheets.
3. Confirm line work is true black, uniformly thick and free of colours and washes, and that cross-section hatching does not obscure any reference sign.
4. Check character height — at least 0.3 cm under Article 14, and at least 0.32 cm if the family is also going to the USPTO.
5. Reconcile every reference sign against the description and claims in both directions. No Belgian examiner will do this for you.
6. Strip sheet annotation to genuinely indispensable keywords, placed so a translation can replace them without redrawing.
7. Plan the colour variants: greyscale or colour is acceptable for an electronic EPO filing, but not for a Belgian national deposit and not under PCT Rule 11.13(a).

Belgian patents are granted without anyone checking any of this. That is convenient at the filing stage and expensive in Brussels, which is the whole argument for getting the sheets right before they are ever filed.

IP Landscape & Resources in Leuven

Key intellectual-property authorities and venues relevant to Leuven:

• OPRI / DIE — Belgian Office for Intellectual Property — the Belgian IP office within the Federal Public Service Economy, where national patents are granted
• Royal Decree of 2 December 1986 (WIPO Lex) — Article 14 sets the Belgian drawing formats, margins, line and reference-sign rules
• Unified Patent Court — Brussels local division — the four-language local division sitting at Rue du Progrès 50, Brussels
• EPO Guidelines for Examination — Part A, Chapter IX — the current European drawing requirements since Rule 46 EPC was deleted

Request Patent Drawing Services in Leuven

Explore related PerspireIP services: Patent Drawing services · patent drawing services in Amsterdam · our Belgium IP services.

Frequently Asked Questions