## Facts

- Inventors sought patent protection for a “rasterizer” used in a digital oscilloscope to improve display of waveform data.
- Digital oscilloscopes convert sampled data points into pixels; connecting points can produce “jaggies” and aliasing artifacts.
- The claimed rasterizer converts vector list waveform data into anti-aliased pixel illumination intensity data to create smoother traces.
- Claim 15 was drafted as a machine/apparatus claim using “means for” limitations.
- Under 35 U.S.C. § 112 ¶ 6, the “means” limitations corresponded to disclosed hardware structures (e.g., arithmetic logic circuitry, ROM, and related logic circuitry) and equivalents.

## Issues

1. Whether the agency’s reconsideration decision by an expanded adjudicatory panel constituted an appealable “decision” permitting appellate jurisdiction.
2. Whether claims 15–19 were patent-eligible subject matter under 35 U.S.C. § 101 or instead an unpatentable mathematical algorithm/abstraction.

## Decision

- The court held it had jurisdiction because the reconsideration ruling constituted a valid, appealable decision.
- The court reversed the § 101 rejection.
- Properly construed, the claims were directed to a “machine” or “apparatus,” not a disembodied mathematical algorithm.
- The claimed rasterizer produced a concrete output: anti-aliased pixel intensity data that improved oscilloscope waveform display.

## Legal Principles

- § 101 is construed broadly across the statutory categories (process, machine, manufacture, composition of matter), subject to exclusions for laws of nature, natural phenomena, and abstract ideas.
- Patent-eligibility turns on the claim as a whole as properly construed, not on whether the invention uses mathematics.
- For “means-plus-function” limitations, § 112 ¶ 6 confines the claim to corresponding structures disclosed in the specification and their equivalents; this construction can render the claim a specific machine rather than an abstract idea.
- A claim to a specific configuration of circuitry (or a programmed implementation that amounts to a specific machine) that applies an algorithm to produce a concrete result is not barred as a mere mathematical formula.

## Conclusion

The court upheld appellate jurisdiction over the agency decision and held that the rasterizer claims, construed as specific hardware-implemented “means” performing defined functions, were directed to a patent-eligible machine under § 101 rather than an unpatentable abstract mathematical algorithm.


In re Alappat, 33 F.3d 1526 (Fed. Cir. 1994) (en banc)