Prohibited Elements

Prohibited Elements

Certain elements are not allowed in USPTO utility patent drawings under any circumstance, unless a very narrow exception applies. These prohibitions exist to ensure technical clarity, avoid legal ambiguity, and maintain a consistent, neutral style across all patent publications.

This chapter lists the elements that must never appear in your drawings and explains why they are prohibited.

1. Scale Indications

The USPTO frequently reduces, enlarges, or scans drawings during publication.
Any indication of scale would become inaccurate.

Not allowed:

  • “Actual Size”
  • “Scale 1:1,” “Scale 1:2,” etc.
  • Scale bars or rulers

Scale indications must not appear in the drawings or the written specification.

2. Immoral, Offensive, or Inappropriate Content

Not allowed:

  • explicit sexual material
  • graphic violence
  • profanity
  • content contrary to public order

Exception:
If such imagery is technically unavoidable to understand the invention (extremely rare), it may be permitted.

3. Trademarks and Service Marks

Not allowed:

  • logos (Coca-Cola®, AT&T®, Nike®, etc.)
  • branded labels or product badges
  • corporate trademarks embedded in drawings

Exception:
Only allowed if you can prove ownership or a legal right to use the mark.

4. Irrelevant Text or Material

You cannot include:

  • commentary
  • marketing text
  • disclaimers
  • descriptive sentences
  • any text not technically necessary

Patent drawings must remain strictly functional.

5. Descriptive Legends (Long Text Labels)

Not allowed:

  • long labels such as “on/off switch,” “serrated surface,” “electrical diagram of widget”
  • paragraphs or sentences
  • captions beneath figures

Exception:
Short labels inside flowchart boxes or schematic blocks are allowed, because they are indispensable for understanding.

6. Center Lines and Axis Indicators

While not always enforced, drawings should avoid:

  • center marks
  • reference circles
  • axis indicators

Unless essential for clarity, these elements should not appear.

7. Brackets or Circles Around Reference Numerals

Do not surround reference numbers with:

  • brackets
  • parentheses
  • circles

This rule applies to both drawings and the written specification.

8. Solid Black Fills or Heavy Shaded Areas

Solid black areas obscure detail and are prohibited, except when:

  • representing a bar graph
  • depicting black color when color is a distinguishing feature of the invention
  • used in authorized color drawings (rare)

Otherwise, shading must use thin hatching or surface lines—not solid fills.

9. Copyrighted Artwork

You cannot include:

  • copyrighted images
  • technical illustrations from books or manuals
  • proprietary CAD drawings
  • screenshots from commercial software

Exception:
Only allowed if you demonstrate proprietary rights or explicit permission.

Summary

The following items are prohibited in patent drawings:

  • scale indicators
  • immoral or inappropriate content
  • trademarks without rights
  • irrelevant or decorative text
  • descriptive legends (except in flowcharts/schematics)
  • centerlines
  • brackets around numerals
  • solid fills (except for limited cases)
  • copyrighted artwork without permission

Staying within these limits ensures your drawings remain compliant, neutral, and acceptable to the USPTO.