What a patent diagram is, the six types examiners see most often, the USPTO rules that apply to them, and how to make one from a text description or sketch.
Six schematic figures generated with PatentFig AI. Open any card to read the full prompt, then start from it in the generator.
Four steps from a plain-language description to a filing-ready schematic figure.
Paste the system description, method steps, or claim language, or upload a whiteboard sketch, slide, or hand-drawn schematic as the reference.
PatentFig AI draws the figure as black-and-white line art with labeled blocks, steps, symbols, or states and a first pass of reference numerals.
Ask for changes in plain language — add a branch, split a block, rename a step — and renumber elements so every figure in the set uses the same numerals.
Run the figure checker against USPTO 37 CFR 1.84 or the EPO, CNIPA, JPO, KIPO, or PCT rules, then export PNG or TIFF for filing and SVG or DXF for later edits.
Both are "drawings" under the rules, but they answer different questions and are described differently in the specification.
Diagrams are schematic and abstract: block diagrams, flowcharts, circuit and wiring schematics, state diagrams, and sequence or timing diagrams. Elements are boxes, symbols, and arrows rather than the outline of a physical part.
Drawings depict the invention itself: perspective, elevation, and plan views, exploded views, and cross-sections with shading and hatching. They carry reference numerals tied to physical parts by leader lines.
A device application typically opens with a block diagram (FIG. 1), follows with the mechanical views, and closes with a flowchart of the method. A software or electrical application may consist of diagrams only.
The schematic figure types that appear most often in utility applications, and when each one earns its place in the set.
Labeled rectangles for modules or components joined by lines or arrows. Use it as FIG. 1 for any system, apparatus, or platform claim so every claimed element has a numbered home.
Start and end terminals, rectangular process steps, and diamond decisions in the order the method is performed. Use it to support every method or process claim, with one step per claimed step.
Standard electrical symbols connected by conductors, with reference numerals in place of component values. Use it when the claim depends on circuit topology rather than on a black-box module.
Physical devices drawn as simple blocks with the conductors, terminals, buses, and connectors between them. Use it for harnesses, sensor networks, and installations where the connection pattern is claimed.
States as labeled nodes and transitions as arrows annotated with their triggering conditions. Use it for controllers, protocols, and user-interface logic that a linear flowchart would flatten.
Vertical lifelines with numbered horizontal messages, or signals plotted against a shared time axis. Use it when the claim recites an exchange between devices or the relative timing of events.
Diagrams are held to the same drawing standard as mechanical views. These are the parts of 37 CFR 1.84 (and 1.74) that come up most often.
Lines, boxes, symbols, and text must be solid black on white. Grey fills, gradients, drop shadows, and colour are not accepted in standard utility drawings (37 CFR 1.84(a)(1)).
Sheets are 21.6 × 27.9 cm (8.5 × 11 in) or A4 (21.0 × 29.7 cm) with a top margin of at least 2.5 cm, left 2.5 cm, right 1.5 cm, and bottom 1.0 cm (37 CFR 1.84(f)–(g)).
Every diagram is a separate view numbered consecutively in Arabic numerals — FIG. 1, FIG. 2 — with letters for partial views such as FIG. 3A (37 CFR 1.84(u)).
The same element keeps the same numeral in every figure, and a numeral is never reused for a different element. Flowchart steps are numbered too, so the description can cite step 104 or step 206 (37 CFR 1.84(p)).
Labels and legends are in English and kept to as few words as possible. Numerals and letters must be at least 0.32 cm (1/8 in) high and remain legible when the sheet is reduced to two-thirds size (37 CFR 1.84(o)–(p)).
Colour is accepted only if a petition explains why it is the only practical way to disclose the invention and is granted. Use line style — solid, dashed, dotted — to distinguish paths instead (37 CFR 1.84(a)(2)).
The specification must include a brief description of the drawings, one line per figure: "FIG. 1 is a block diagram of a monitoring system according to one embodiment" (37 CFR 1.74).
The errors that most often trigger a draftsperson objection or a Notice to File Corrected Application Papers.
Coloured arrows or shaded blocks that carry information disappear when the office prints the sheet in black and white. Encode the difference with line style or labels.
Boxes without reference numerals cannot be cited in the description, and a module numbered 110 in FIG. 1 that becomes 210 in FIG. 3 looks like a different element.
Icons, logos, screenshots, clip-art clouds, rounded gradients, and drop shadows come straight from slide decks and fail the line-art requirement. Draw a network as a plain outline, not a picture.
Labels pasted from a source diagram often fall below 0.32 cm once the sheet is scaled, and non-English labels must be translated before filing.
Step wording that drifts from the method claim weakens the figure as support for amendments. Mirror the claim language and give each claimed step its own numbered box.
Patent diagrams
Describe the system or method, generate a numbered black-and-white diagram, check it against your patent office, and export.