MagSil Corp. v. Hitachi Global Storage Technologies, Inc.
687 F.3d 1377
| Fed. Cir. | 2012Background
- MIT is assignee and MagSil exclusive licensee of the ’922 patent, filed March 1995, issued May 1997; claims cover read-write sensors for hard disk drives.
- The patent discloses a tri-layer tunnel junction whose resistance changes with magnetization direction, enabling sensing via tunneling magnetoresistance.
- The asserted claims broadly cover a junction whose resistance changes by at least 10% at room temperature when energized, without requiring specific fabrication steps.
- The specification discloses achieved changes up to 11.8% at room temperature and discusses factors affecting ΔR/ΔR, but does not enable higher changes across the full claimed range.
- MagSil asserted claims cover open-ended resistance changes from 10% to infinity; the district court found lack of enablement due to insufficient disclosure at filing.
- District court granted summary judgment that claims 1-5, 23-26, and 28 are invalid for lack of enablement; Hitachi was found non-infringing.
Issues
| Issue | Plaintiff's Argument | Defendant's Argument | Held |
|---|---|---|---|
| Whether the claims are enabled across their full scope. | MagSil argues open-ended 10%+ range is enabled. | Hitachi argues the specification only enables up to 11.8% and cannot support infinity. | Yes; claims lack enablement across full scope. |
| Whether open-ended claim language (10% to infinity) can be enabled. | Open-ended term permits broad scope. | Open-ended language is not automatically enabled across infinite range. | Open-ended language not enabled across full scope. |
| Whether Fisher/Gillette guidance supports rejection of open-ended claims. | Open-ended term resembles Fisher open-ended sales of higher potency. | Gillette distinguishes from this technology; open-endedness not automatically enabled. | Court adopts Fisher-style open-ended enablement analysis; claims not enabled. |
| Impact on infringement judgment given invalidity. | If valid, infringement could exist. | No infringement when claims are invalid. | Affirmed non-infringement due to enablement failure. |
Key Cases Cited
- In re Fisher, 427 F.2d 833 (CCPA 1970) (open-ended claims must be enabled across scope; potency example used to limit scope)
- Gillette Co. v. Energizer Holdings, Inc., 405 F.3d 1367 (Fed. Cir. 2005) (open-ended terms require enabling disclosure; distinguishing Razor example from technology here)
- Sitrick v. DreamWorks, LLC, 516 F.3d 993 (Fed. Cir. 2008) (scope must be enabled to prevent overbreadth)
- AK Steel Corp. v. Sollac, 344 F.3d 1234 (Fed. Cir. 2003) (enablement requires disclosure commensurate with claimed scope)
- Genentech, Inc. v. Novo Nordisk, A/S, 108 F.3d 1361 (Fed. Cir. 1997) (enablement tied to ordinary skill and disclosure sufficiency)
- Microsoft Corp. v. i4i Ltd. P'ship, 131 S. Ct. 2234 (2011) (clear and convincing standard for invalidate based on non-enablement)