## Facts

- Day-Brite manufactured fluorescent lighting fixtures and obtained a design patent on a cross-ribbed reflector; its application for a utility patent on the same device was denied.
- Compco (through a predecessor) marketed fixtures with a substantially similar reflector design after Day-Brite’s product entered the market.
- Day-Brite sued in federal court alleging (1) design patent infringement and (2) unfair competition under Illinois law based on copying that allegedly caused trade and customer confusion.
- The district court held the design patent invalid but found unfair competition under Illinois law, despite an express finding of no deceptive or fraudulent practices by Compco.
- The district court enjoined Compco from selling reflectors “identical to, or confusingly similar to” Day-Brite’s and ordered an accounting of damages.
- The Seventh Circuit affirmed the unfair-competition judgment and related relief.

## Issues

1. Whether a state may, through unfair-competition law, enjoin or award damages for copying an unpatented (or invalidly patented) product design when the relief functions as patent-like protection.

## Decision

- The Supreme Court reversed the judgment.
- A product design not entitled to patent protection may be copied freely, even if the design has come to identify its maker in the trade.
- Illinois could not use unfair-competition law to enjoin copying of the unpatented design or to award damages for copying alone because such relief conflicts with federal patent policy.
- Justice Harlan concurred in the result.

## Legal Principles

- Federal patent law preempts state-law rules that effectively grant exclusive rights in unpatented (or invalidly patented) designs by prohibiting copying or imposing damages for copying.
- Designs left unprotected by the federal patent system remain in the public domain and are available for copying as part of the federal scheme favoring competition in unpatented articles.
- States may regulate deception (e.g., passing off, false labeling, or other misleading conduct) but may not impose liability merely because a competing product copies the design of an unpatented article.

## Conclusion

The Court held that state unfair-competition relief cannot operate as a substitute for patent protection by barring or penalizing copying of an unpatented design; only measures aimed at preventing deception are permissible under state law.


Compco Corp. v. Day-Brite Lighting, Inc., 376 U.S. 234 (1964)