## Facts

- Petrus A.C.M. Nuijten applied for a patent on technology that embeds digital watermarks into audio/video signals while reducing perceptible distortion.
- The application described processing steps that encode a watermark and then further process the result to compensate for watermark-induced distortion.
- The application included multiple claim types, including method claims, device/system claims, storage-medium claims, and claims directed to the encoded signal itself.
- The disputed claims covered the encoded signal “as such,” including transitory, propagating electromagnetic signals, without tying the signal to a physical storage medium or other tangible article.
- A USPTO examiner rejected the signal claims under 35 U.S.C. § 101 as outside the statutory subject-matter categories; the Board of Patent Appeals and Interferences affirmed.
- Nuijten appealed to the United States Court of Appeals for the Federal Circuit, challenging only the § 101 rejection of the signal claims.

## Issues

1. Whether a man-made, encoded, propagating signal constitutes patent-eligible subject matter under 35 U.S.C. § 101.
2. Whether such a signal fits within any of § 101’s four statutory categories: process, machine, manufacture, or composition of matter.

## Decision

- The Federal Circuit affirmed the Board’s § 101 rejection of the signal claims.
- The court held that the claimed signal is not a process or a machine because it claims a result (a signal) rather than a series of acts or a concrete device with parts.
- The court held the signal is not a “manufacture” because a propagating signal is intangible and transitory and is not claimed as a tangible article or commodity.
- The court held the signal is not a “composition of matter” because it is not a physical combination of substances or a material composition; it is a pattern of variations in energy.
- Judge Linn concurred in part and dissented in part, concluding the signal claims could qualify as a “manufacture” under a broader reading of § 101.

## Legal Principles

- Section 101 patent eligibility requires that claimed subject matter fall within one of four exclusive statutory categories: process, machine, manufacture, or composition of matter.
- A claim directed to a transitory, propagating signal, untethered to a tangible medium, is not a patent-eligible “manufacture” because it lacks the required tangible article-like character.
- An encoded signal, as claimed, is not a “composition of matter” where it is not a material combination of substances but instead a configuration of electromagnetic or electrical energy.
- Patent protection for information-encoding technology may be available through claims to methods, machines, or tangible storage media, even if claims to “signals per se” are not eligible.

## Conclusion

The Federal Circuit held that claims to an encoded, propagating electromagnetic signal, apart from any physical medium, are not patent-eligible under § 101 because they do not qualify as a process, machine, manufacture, or composition of matter, and the court declined to recognize a new eligibility category for signals.


In re Nuijten, 500 F.3d 1346 (Fed. Cir. 2007)