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A design patent claim has almost no words in it. One sentence points at the figures, and everything you own is decided by which lines are solid and which are dashed. That makes design patent broken lines the most consequential drafting decision in the entire application — more consequential than anything you will write in the specification.
Get the split wrong in one direction and you have claimed the whole article, so a competitor changes the handle and walks away. Get it wrong in the other direction and the examiner objects, or worse, you discover during a continuation that the boundary you wanted was never supported. Here is what the rules actually say, and the seven checks worth running before the drawings go out the door.
What Design Patent Broken Lines Actually Claim
A design patent under 35 U.S.C. § 171 protects the ornamental appearance of an article, and the drawing is the claim. There is no prose limitation to fall back on. So the first question in any design filing is not what to write but where to stop drawing in solid line.
The governing rule is 37 CFR 1.152, which requires that the design “be represented by a drawing that complies with the requirements of § 1.84” and contain “a sufficient number of views to constitute a complete disclosure of the appearance of the design.” On dashes it is narrow and specific: broken lines “may be used to show visible environmental structure, but may not be used to show hidden planes and surfaces that cannot be seen through opaque materials.”
The working convention practitioners apply every day is simpler than the rule text:
- Solid line — claimed. It is part of the design an accused product must have.
- Broken line — disclosed but not claimed. It gives the examiner and the public context without becoming a limitation.
- Everything left out entirely — not disclosed at all, which can create a completeness objection if the article looks unfinished.
Here is the part that trips up people coming from utility practice. Converting a solid line to a broken line broadens the claim. Infringement of a design patent is judged on the claimed features under the ordinary observer test, so every feature you dash away is one fewer thing an accused product needs to share with you. Utility instincts say more detail equals more protection. In design practice, more solid line usually means less.
The Two Jobs Dashes Do Under MPEP 1503.02
MPEP 1503.02 is blunt about it: the two most common uses of broken lines are “(1) to disclose the environment related to the claimed design and (2) to define the bounds of the claim.” Those are different jobs and the Office expects you to know which one you are doing.
Environment. “Structure that is not part of the claimed design, but is considered necessary to show the environment in which the design is associated, may be represented in the drawing by broken lines.” A dashed phone body around a claimed icon, a dashed vehicle around a claimed wheel, a dashed bottle around a claimed cap.
Bounds. A boundary dash cuts a claimed region out of a larger article. You are telling the world you claim the area on one side of that line and nothing on the other. This is the mechanism behind every partial design filing, and it is also where the priority problems live.
A practical consequence people miss: surface shading belongs only on claimed subject matter. Shading unclaimed broken-line structure muddies exactly the boundary the dashes were drawn to establish, and examiners will say so.
There is a trade-off here that rarely makes it onto a drafting checklist. Because design patent broken lines broaden what the claim covers, they also widen the field of prior art that can be read against it. A claim to a whole coffee maker is hard to infringe but easy to distinguish from earlier designs. Dash away everything except the handle profile and the claim suddenly catches far more products — and far more references. The right amount of dashing is a commercial judgment about what competitors are likely to copy, informed by a look at what already exists in the class, not a mechanical preference for the broadest possible claim.
5 Things a Broken Line May Never Show
Rule 1.152 and MPEP 1503.02 both contain outright prohibitions. These are the ones that generate real objections:
- Hidden planes and surfaces. Dashes may not depict what “cannot be seen through opaque materials.” A design patent covers appearance; internal structure is not appearance.
- Alternate positions in the same view. 37 CFR 1.152 states that “[a]lternate positions of a design component, illustrated by full and broken lines in the same view are not permitted in a design drawing.” Show the second position in its own figure.
- Relative importance. Per MPEP 1503.02, “broken lines are not permitted for the purpose of indicating that a portion of an article is of less importance in the design.” A feature is claimed or it is not; there is no middle tier.
- Shaded unclaimed matter. Surface shading on broken-line structure confuses claim scope and invites a § 112 objection.
- Environment in a photograph. This one surprises people. Rule 1.152 provides that photographs submitted in lieu of ink drawings “must not disclose environmental structure but must be limited to the design claimed for the article,” and that photographs and ink drawings may not be combined as formal drawings in one application. You cannot dash out a background in a photo — if you need a disclaimer, you need line drawings.
That last point quietly settles a lot of arguments. Teams who want to file quickly from product photography end up with a claim to the whole photographed article, which is almost never what they wanted. If partial-design scope matters, budget for proper drawings from the start; our note on drawing mistakes that trigger office actions covers the downstream cost.
The Specification Statement That Makes the Dashes Stick
Dashes on a sheet are not self-explaining. The specification has to say what they are for, and the Office requires the description. The standard sentence most practitioners use is some form of: the broken lines are for the purpose of illustrating portions of the article that form no part of the claimed design.
Where broken lines are doing both jobs in the same figure, MPEP 1503.02 wants the description to make the distinction visible, suggesting language along the lines of: “The broken lines immediately adjacent the shaded areas represent the bounds of the claimed design while all other broken lines are directed to environment.” Two purposes, two explanations.
Skip the statement and you are inviting an indefiniteness rejection under 35 U.S.C. § 112, because a reader cannot tell what the applicant regards as the invention. It is a thirty-second fix at drafting and an expensive one after a first action.
Unclaimed Boundary Lines and the In re Owens Trap
The most expensive mistake in this area is not a formality — it is priority. In In re Owens, 710 F.3d 1362 (Fed. Cir. 2013), the applicant filed a continuation that introduced a broken boundary line splitting a region that had been claimed as a whole in the parent. The Federal Circuit treated that line as an “unclaimed boundary” — a line that divides a previously claimed area and signals that the applicant has disclaimed the portion beyond it while claiming the area within.
The court held that such a line, like any amendment, must satisfy the written description requirement to earn the benefit of the parent’s filing date under 35 U.S.C. § 120. Because nothing in the parent disclosure suggested that particular division of the bottle’s surface, the continuation lost priority. In a design portfolio, losing priority frequently means losing the case.
MPEP 1503.02 reflects the same logic on amendments: a straight broken boundary line may be added where it complies with written description, but any boundary other than a straight broken line risks being treated as new matter.
The planning lesson is to think about future partial claims before the parent is filed. If the commercially important region of the product might later need to stand alone, disclose it as a distinguishable region in the parent — along a design seam, a material change, or an existing solid feature line — rather than inventing an arbitrary cut two years later.
How 37 CFR 1.84 Formalities Break Dashed Drawings
Rule 1.152 does not stand alone; it incorporates 37 CFR 1.84 wholesale. That matters more for broken lines than for solid ones, because dashes are the first thing to disintegrate in reproduction.
- Line quality. 37 CFR 1.84(l) requires every line to be durable, clean, black, sufficiently dense and dark, and uniformly thick and well-defined. Faint or hairline dashes that look fine on screen frequently do not survive scanning.
- Consistent dash pattern. Vary dash length between figures and a reviewer cannot tell environment from boundary. Pick one pattern for environment and one for bounds, and hold them across every sheet.
- Shading discipline. Surface shading under 1.84(m) shows contour on claimed surfaces. Keep it off the dashed regions entirely.
- Sheet layout. Margins, view numbering and sheet numbering under 1.84 apply to design cases exactly as they do to utility cases.
Most of the drawing objections we see on design cases are not conceptual disagreements about scope. They are reproduction problems dressed up as rejections, and they cost a response cycle either way. The distinctions in our guide to utility versus design drawing practice are worth reviewing before a first design filing.
Broken Lines Abroad, and the Rule 46 EPC Myth
A US broken-line strategy does not port cleanly overseas, and the citations people reach for are often stale.
Start with a correction that still circulates in drawing guides: Rule 46 EPC was deleted with effect from 1 February 2023. The form requirements for European patent application drawings now sit in Rule 49 EPC together with the EPO Guidelines at Part A, Chapter IX. Any checklist still citing Rule 46 EPC for drawing formalities is out of date. Separately, the EPO began accepting colour drawings and photographs in applications from 1 October 2025 — a genuine change, and one we cover in our note on EPO colour drawing practice.
More fundamentally, none of that governs designs. The European Patent Office does not grant design rights at all. Design protection in Europe comes from the EUIPO for EU-wide registrations or from national offices, and those systems have their own disclaimer practice — broken lines, but also colour shading, boundaries and blurring are accepted visual disclaimers in EU design filings.
If you are routing a design family through the Hague system, remember that a single international application is examined against each designated office’s requirements. A drawing set built purely to US broken-line convention can clear one office and draw a refusal at another, so the safest approach is to prepare the figures to the strictest designated standard rather than the most convenient one.
A 7-Point Check Before the Drawings Go Out
Run this before every design filing. It takes ten minutes and it is the cheapest insurance in the whole prosecution budget.
- Confirm every solid line is a feature you would be willing to require of an infringing product.
- Confirm no broken line depicts hidden structure behind opaque material.
- Confirm no figure shows alternate positions in full and broken line together.
- Confirm surface shading appears only on claimed, solid-line surfaces.
- Confirm the specification describes the broken lines, and distinguishes environment from bounds when both appear.
- Confirm any boundary line is straight, and is supported by something actually disclosed — the Owens question.
- Confirm the dashes reproduce cleanly at print resolution under 37 CFR 1.84(l).
If more than one of those comes back uncertain, the drawings are not ready. Design cases move fast at the USPTO relative to utility cases, and a formal drawing objection is one of the few things that reliably slows them down.
One further habit is worth building at portfolio level. Where a product matters commercially, file more than one design application against it: a broad filing that dashes away everything but the signature feature, and a narrower filing that claims the article as a whole. The two fail in opposite conditions — the broad one to prior art, the narrow one to a competitor’s minor restyle — so holding both is materially stronger than agonising over a single set of design patent broken lines. Filing fees for design applications are modest compared with the cost of discovering, mid-litigation, that the one claim you have sits on the wrong side of the line.
How PerspireIP Can Help
Our illustrators prepare design and utility figures to USPTO, EPO and PCT standards every week, and they draft to claim strategy rather than just to formality — which is exactly where broken-line decisions are won or lost. See our patent drawing services, or talk to us about a design filing before the figures are finalized. This article is general information, not legal advice; consult a qualified attorney for your situation.
Frequently Asked Questions
Do broken lines make a design patent broader or narrower?
Broader. Infringement is assessed on the claimed, solid-line features, so every feature moved to broken line is one fewer element an accused product must share. Adding solid line narrows the claim.
Do I have to explain the broken lines in the specification?
Yes. The specification must describe what the broken lines represent, and where they serve both purposes in one figure, MPEP 1503.02 expects the description to distinguish environment from the bounds of the claim.
Can I add a broken boundary line in a continuation?
Only if the parent disclosure supports it. In re Owens, 710 F.3d 1362 (Fed. Cir. 2013), held that an unclaimed boundary line must satisfy the written description requirement to keep priority under 35 U.S.C. § 120.
Can I use broken lines in design patent photographs?
No. Under 37 CFR 1.152, photographs filed in lieu of ink drawings must not disclose environmental structure and must be limited to the claimed design, and photographs cannot be combined with ink drawings as formal drawings in one application.
Does Rule 46 EPC still govern drawing form at the EPO?
No. Rule 46 EPC was deleted with effect from 1 February 2023; drawing form requirements now sit in Rule 49 EPC and the EPO Guidelines Part A, Chapter IX. The EPO also does not grant design rights — EU designs are handled by the EUIPO.
Can broken lines show that a feature is less important?
No. MPEP 1503.02 states that broken lines are not permitted for the purpose of indicating that a portion of an article is of less importance in the design. A feature is either claimed or disclaimed.