US 6229542

Patent Overview — US 6,229,542 B1

Title: Method and apparatus for managing windows in three dimensions in a two dimensional windowing system

Assignee: Intel Corporation (original assignee and current assignee as listed). Inventor: John David Miller. Application: US 09/113,814, filed 1998-07-10. Granted/Published: 2001-05-08. Legal status: Expired – Lifetime (anticipated expiration 2018-07-10). Classification: G06F 3/04815 (3D metaphor-based interaction).

Purpose: The patent addresses window overcrowding in graphical user interfaces. Prior art windowing systems manage a "two and one half dimensional" space — horizontal and vertical coordinates plus an overlap order — so managing many windows becomes "cumbersome, confusing and slow." The invention extends window representation to include true depth, letting windows be positioned in a genuine 3D space and rotated or viewed off-axis, thereby occupying less screen space while retaining their appearance instead of being reduced to icons.

Plain-language scope: In an embodiment, the 3D space is maintained behind active 2D windows, like a traditional desktop image. A user gesture can "push back" a window: its pixels are captured and applied as a texture onto a similarly shaped 3D display object located where the window was. Conversely, activating a window moves and orients that display object to a location in the 3D window, and the actual 2D window is displayed over the top of it, giving the illusion that the window exists in 3D. An active window appears in the foreground; inactive windows appear in the background. Optional elements include a bottom surface with grid lines and "false shadows" allowing obscured windows to be selected by their shadows. The approach is intended to work without modifying existing application programs, and pushed-back windows may remain fully active.

Source: https://patents.google.com/patent/US6229542/en

What the excerpt does not establish: It is an abridged Google Patents page. The full claims, complete specification text, all drawing contents, and the full reference list are not reproduced here; noted advantages such as users' preference for 3D environments rest on "anecdotal evidence" per the text.

I'll research litigation involving US Patent 6,229,542. Let me search multiple sources.

Let me search more targeted litigation databases.

Let me check the Unified Patents litigation portal and other litigation-specific sources directly.

Litigation Search Results: US Patent No. 6,229,542

Bottom line

I found no litigation involving US Patent No. 6,229,542 (Method and apparatus for managing windows in three dimensions in a two dimensional windowing system; filed 1998‑07‑10; granted 2001‑05‑08; inventor John David Miller; assignee Intel Corp.).

Searches of publicly indexed litigation sources (Google Patents litigation/citation data, CourtListener/Justia dockets, Unified Patents‑style litigation portals, PTAB records, and general web searches for the specific number) returned no case in which US 6,229,542 was asserted as a patent‑in‑suit. The Google Patents record for this patent lists an extensive "Cited By" set (including related Intel/Microsoft/Apple/Sun families) but identifies no litigation, and the patent expired at the end of its term on 2018‑07‑10 ("Anticipated expiration," now "Expired – Lifetime").

Important caveat — do not confuse these with US 6,229,542

My searches repeatedly surfaced complaints referring to a "'542 patent," but none of those are US 6,229,542. Interpreting the identifiers literally, each of the following is a different patent sharing only the trailing digits "542":

Each of these uses "'542" as a local shorthand for patents with different full numbers. I did not find any of them mapping to 6,229,542.

Sources consulted

• Google Patents record for US 6,229,542B1 — https://patents.google.com/patent/US6229542B1/en (full text, "Cited By" and "Citations" tables; no litigation section)
• Google Patents litigation portal (portal.unifiedpatents.com/patents/…) — retrievals for this number returned no case list
• CourtListener / Justia RECAP dockets and opinions (multiple "'542" hits, all other patents)
• PTAB petition filings referencing "'542" (NuVasive and Jawbone‑family matters — different patents)

Recommended next steps to confirm (limitations of my search)

Public web search is not a complete litigation‑clearance tool. To make a definitive negative finding, I would (and you may want to) run:

1. Unified Patents Litigation Case List — https://portal.unifiedpatents.com/litigation/caselist — filter by patent number.
2. PACER / Docket Navigator — a paid docket search on "6,229,542" across all districts.
3. USPTO PatentCenter "Litigation" / Assignment tabs and the USPTO Patent Assignment Search (to check for any assignment to an NPE/litigation entity).
4. PTAB / IPR search for 6,229,542 (none found).
5. CAFC docket search for the patent number.

Given the patent's priority date (1998), its use of "G06F3/0481 / G06F3/04815" 3D‑GUI classifications, and its 2018 expiration, it would be unusual for active litigation to exist now — but I cannot certify a negative from the tools available here.

Bottom line for your file: No known litigation involving US 6,229,542 was found; the numerous "'542 patent" hits in the literature are distinct patents.

I'll verify the structured block's "no proceedings" default against live sources before finalizing.

PTAB / AIA Trial Proceedings — US 6,229,542

Patent: Method and apparatus for managing windows in three dimensions in a two dimensional windowing system
Patent owner of record: Intel Corporation (original assignee; inventor John David Miller)
Filing date / priority date: 1998-07-10 · Grant date: 2001-05-08
Structured PTAB source: USPTO ODP returned no AIA trial proceedings for this patent as of the most recent ingest.
Verification date: 2026-09-30

Proceedings overview

Total AIA trial proceedings on file: 0. No IPR, PGR, or CBM petition has been filed against US 6,229,542 — nothing instituted, nothing denied, nothing terminated, nothing appealed to the Federal Circuit. Independent web searching (Google Patents litigation/PTAB metadata, PTAB E2E/PTAB Decisions, National Law Review PTO Litigation Center petition dockets, Unified Patents portal) surfaced no proceeding, no FWD, and no CAFC appeal involving this patent number.

Defensive posture for a defendant today: the absence of PTAB activity is not the meaningful signal here — the expiration is. Google Patents' structured data records an anticipated expiration of 2018-07-10 (20 years from the 1998-07-10 filing) with legal status "Expired – Lifetime," and no terminal disclaimer, extension, or PTA adjustment appears that would push that date out by any material amount. A patent that expired in 2018 cannot support a live infringement case in 2026: § 286's six-year damages lookback window has closed for any act of infringement, and post-expiration activity is not actionable at all. So the bottom line is not "the patent has survived IPRs and is hardened" — it is "the patent is expired and there is no PTAB record at all; verify the expiration date and your product's pre-2018 timeline before you spend a dollar responding to a demand letter."

Proceedings on file

None. There is no proceeding to report. I am not listing any proceeding numbers, because doing so would require inventing them, and no candidate number exists in the structured data or in any source I searched.

What I searched, and what I found (or didn't)

Caveat stated plainly: I could not run an exhaustive docket sweep of every district court and every PTAB reexam control number within this task's tool budget. It is possible a non-appealable ex parte reexamination request exists that did not surface; I found no evidence of one. What I can affirm with high confidence is the core fact: no AIA trial proceeding (IPR/PGR/CBM) has ever been instituted or even petitioned against this patent, consistent with the ODP block.

Strategic summary

Claim status — CANCELED vs. SUSTAINED vs. UNTESTED. All 25 claims — independent claims 1, 11, 17, and 23, and every dependent claim — are UNTESTED at the PTAB. Not one claim has been canceled, and not one has been confirmed in an FWD. There is therefore no claim-level IPR holding you can cite as a clean "claim 1 is dead" argument. That is a colder comfort than a cancellation, but it is not the operative fact either: the claims expire with the patent, and the patent expired on or about 2018-07-10.

Estoppel landscape. Because no IPR/PGR/CBM was ever filed, § 315(e)(2) estoppel does not exist against anyone — not against Intel, not against any third party, and not against any privy. No petitioner has been estopped, because there has been no petitioner. Conversely, you get no benefit from estoppel either: there is no prior petitioner whose grounds were "raised or reasonably could have been raised" that you could shelter behind. Every ground is theoretically open to you (§ 102/§ 103 on patents and printed publications; § 112 in PGR only — but PGR is time-barred under § 321(b) since the patent issued long before the 9-month window and before PGR even existed for this filing date). In practice the open-ground point is academic given expiration.

Prior art worth knowing about if you ever needed it. The patent's own face already of-record includes several pre-1998 3D-windowing/3D-workspace references that a challenger would build on: US 5,880,733 (Microsoft, priority 1996-04-30 — "Display system and method for displaying windows of an operating system to provide a three-dimensional workspace"), US 5,835,094 (Compaq, 1996-12-31 — "Three-dimensional computer environment"), US 5,754,809 (Dell, 1995-12-12 — "Perspective windowing technique for computer GUI"), US 5,838,326 (Xerox, 1996-09-26 — moving document objects in a 3-D workspace), and the non-patent literature Card, Stuart K. et al., "The WebBook and the Web Forager: An Information Workspace for the World-Wide Web," CHI 96, pp. 111–117 — all cited on the face of the '542 patent. Being "considered by the examiner" does not bar using them in an IPR, but it does mean an examiner already found the claims distinguishable over them, which is a caution flag for any § 103 theory built solely on of-record art. The '542 also sits in a dense prospective-citation web — 210 third-party "cited by" entries in the Google Patents view and 414 in the ODP view, including Microsoft's Task Gallery family (1999-04-06 priority) and Sun Microsystems' 3D windowing applications (GB 2406768 / GB 2406770, priority 2003-09-15) — which tells you the general idea was heavily built upon, not that any of those later filings are invalidating art.

Pattern signals. None of the classic PTAB patterns are present: no repeat petitioner, no defensive aggregator (Unified Patents et al.) in the chain, no PTAB appeal history by the patent owner, no joinder, no settlement-linked termination. Intel has never had to defend this patent at the Board. The patent's family is a single-member family (US 09/113,814 only; no continuations or divisionals claimed from it), so there is no sibling patent that survived to carry the family's assertion value forward.

Recommended next steps

1. Lead with the expiration date, not with the PTAB record. Confirm the expiration independently in USPTO Patent Center (maintenance-fee history and any § 154(b) PTA or terminal disclaimer) before drafting anything. If the 2018-07-10 expiration is confirmed, the demand is moot and the response is short. Link: https://patentcenter.uspto.gov/ (search application 09/113,814).
2. If, and only if, someone asserts it anyway: there is no PTAB FWD to link to and no claim to quote as canceled. Do not represent to a court or an adversary that any claim of the '542 has been invalidated — it has not. The dispositive defenses are statutory (§ 286 time bar and expired-term unenforceability for post-2018 conduct), not PTAB-based.
3. If a live pre-2018 damages theory somehow surfaces (it would require an accrued claim within the § 286 window), two things follow: (a) an IPR is technically available even against an expired patent where past damages are live, but the Board frequently exercises § 314(a)/Fintiv-style discretion and, more fundamentally, an expired patent can't be amended to survive — rendering IPR a "no-future-value" exercise; and (b) the of-record art above becomes the obvious starting kit, with the caveat noted about examiner consideration.
4. Do not treat the zero-proceeding record as itself a defense. "No IPRs were filed" is a neutral fact here; it is explained most simply by the patent's age and 2018 expiration, not by litigation-forced hardening. For reference on how to check for late-added proceedings, the canonical sources are PTAB E2E / PTAB Decisions (https://ptacts.uspto.gov/ptacts/) and the Federal Circuit docket/CourtListener (https://www.courtlistener.com/); neither shows anything for this patent as of 2026-09-30.

Bottom line: zero AIA trial proceedings; zero canceled claims; zero estoppel; and a patent whose term appears to have run out in 2018 — which, for a defendant in 2026, is worth more than any IPR win would be, provided you verify it.

I'll research the assignment record for this patent across USPTO sources and asserter directories.

Let me check for litigation and NPE assertion records, and any post-issuance transfer.

I was able to retrieve the Google Patents legal-events record and asserter-directory cross-references, but I could not directly execute a live query against the USPTO Assignment Center database (assignmentcenter.uspto.gov / assignment.uspto.gov) — my searches surfaced no reel/frame data for this patent. I flag that limitation explicitly below rather than infer reel numbers.

Inventors

John David Miller — sole named inventor (per US6229542B1 front page). Employer at time of filing: Intel Corporation, on the following evidence:

• The patent names only Miller, and the assignment record shows Miller assigning to Intel Corporation on the same date as the filing (1998-07-10) — the standard employee-inventor → employer assignment pattern for a corporate R&D invention. This is consistent with Intel Architecture Labs–era HCI work (the specification's marketing of a "3D desktop" as a replacement for the Windows 95/98/NT desktop reads as internal Intel platform research, and Intel built a follow-on portfolio — e.g., US 6,597,358, "presenting two and three-dimensional computer applications within a 3D meta-visualization").
• Antecedent-based assignment (executed at filing, not later) supports employee status; a non-employee contractor typically assigns at a later date or via a separate work-for-hire instrument.

Unusual patterns: None detected. I found no evidence of the inventor departing Intel within 12 months of filing. Be aware this is an absence-of-evidence finding, not a verified employment history — I did not locate a personnel record or a later inventor assignment that would prove or disprove departure. No fire-sale-precursor signature is present.

Original assignee

Intel Corporation (Santa Clara, CA; Delaware corporation) — named on the issued patent and the sole recorded assignee.

• Primary line of business: semiconductor design/manufacture; broader computing platforms, client software, and graphical-user-interface research.
• Product embodying the claims: Unclear / not confirmed. The claims cover pushing 2D windows into a 3D desktop space as textured 3D objects. I found no shipping Intel-branded product that practices the claims, and no litigation or product literature tying a commercial product to this specific patent. The patent text itself is written as a windowing-system research disclosure (it explicitly describes implementation "as an integral part of a window system and/or window manager" such as the Windows™ window system), which is consistent with a defensive/research portfolio entry rather than a product-defining patent.
• Current status: Operating. Intel remains an active publicly traded operating company; there is no bankruptcy or dissolution of the original assignee. (Intel did undergo significant restructuring/cost-reduction in 2024–2025, but that is not a bankruptcy event and does not affect the chain.)

Assignment timeline

Data-availability caveat. The precise reel/frame identifiers and the correspondent of record were not exposed by any source I could reach. The Google Patents legal-events feed lists a single post-filing recording described only as "ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS)," with no reel/frame in the text. I therefore report the conveyance and parties with confidence but mark reel/frame and correspondent as not retrieved. Do not treat my inability to pull them as proof they are absent.

• 1998-07-10 (executed) / recorded 1998-07-10 — Reel not retrieved / Frame not retrieved
  • Conveyance: Assignment (recorded by Google Patents legal events as "reassignment … ASSIGNMENT OF INTEREST; SEE DOCUMENT FOR DETAILS")
  • Assignor: MILLER, JOHN DAVID (individual inventor)
  • Assignee: INTEL CORPORATION
  • Correspondent: Not retrieved. Because this is the only recorded link in the chain, the "repeat correspondent" test in §3 below cannot be run — there is no recurrence to observe.
  • Context: Antecedent/inventor-to-employer assignment executed at filing — i.e., the original corporate ownership transfer, not an acquisition.

No post-issuance assignments of record. Despite targeted searches (Google Patents legal events, general web, and asserter-directory cross-references), I found no subsequent assignment, security agreement, merger, change-of-name, license, or release for US 6,229,542. The patent is recorded as Expired – Lifetime with anticipated expiration 2018-07-10, and its only recorded owner from 1998 through expiry is Intel Corporation. That is itself the finding: Intel never recorded a transfer out of its name.

This is reinforced by a specific negative cross-reference: Intel's own later NPE-related litigation (e.g., Intel Corp. v. Fortress Investment Group, N.D. Cal. 3:19-cv-07651) and its 2021 Senate Judiciary testimony describe Intel patents being pried out by aggregators and shell LLCs — but US 6,229,542 does not appear among those transferred-in-suit portfolios in anything I retrieved.

Timeline diagram

timeline
    title Ownership of US 6229542
    1998 : Filed by John David Miller
         : Assigned to Intel Corporation
    2001 : Patent issued to Intel
    2018 : Patent expired

NPE / troll-pattern signals

Verdict

Insufficient data (per the defined bucket "no records, or only the original assignment"). The complete record I could reach consists of a single assignment — inventor John David Miller → Intel Corporation, executed and recorded 1998-07-10, the same date the application was filed — followed by no further recorded conveyance through the patent's 2018-07-10 expiry. There is no shell-entity transfer, no known asserter, no cascading chain, no bankruptcy sale, and no pre-litigation transfer in the record, so none of the NPE signals fire. The one diagnostic I could not run (repeat-correspondent, signal #3) is un-runnable by construction with a one-link chain, and I have marked it unclear rather than guessing.

Key caveat: Because I could not directly query the USPTO Assignment Center, treat "no post-issuance assignment" as strongly indicated but not independently confirmed at the reel/frame level; the authoritative check is to search patent number 6229542 at the USPTO Assignment Center (https://assignmentcenter.uspto.gov/) and confirm a single-chain record with one 1998 conveyance, no reel/frame beyond it, and Intel as assignee. If that query returns additional reel/frame entries that I could not surface, the verdict moves to whichever category those entries support.

Verification link: https://assignmentcenter.uspto.gov/ (search "6229542" under Patent Number), mirrored at https://assignment.uspto.gov/patent/index.html.

I'll verify details on the most load-bearing references before mapping them to claims. Let me search several of them concurrently.

I have strong detail on the top references. Let me verify the remaining cited references so each mapping is grounded.

Prior Art Analysis — US Patent 6,229,542 (Miller / Intel)

Building on the bibliographic and litigation sections already produced; those are not repeated. This section adds the prior-art review the earlier sections did not cover.

1. Scope, method, and the legal frame (do not skip)

What I searched. I ran targeted web retrievals against the Google Patents full-text record for US6229542B1, the patentimages.storage.googleapis.com facsimiles, uspto.report grant records, Unified Patents portals, and ACM/DBLP records. I could not run a structured USPTO PatentCenter/PAIR or Docket Navigator query through these tools, so the analysis below rests on (a) the authoritative citation table printed in the patent itself and (b) independent verification of the load-bearing references. Treat the "anticipates" column as my analytical mapping, not as a reproduction of the examiner's actual rejections (the file wrapper is not in front of me).

Legal frame — critical. US 6,229,542 was filed 1998-07-10 with a priority date of the same day, i.e., it is governed by the pre-AIA 35 U.S.C. § 102 / § 103. Three dates matter:

• § 102(b) critical date = 1997-07-10 (one year before filing). Only art published/enacted before this date is § 102(b) art (and can be used on the claims with no "invention date" lag).
• § 102(a) — art patented/published/known before the applicant's invention (a rolling date).
• § 102(e) — a U.S. patent is prior art as of its effective U.S. filing date if that date precedes the applicant's invention (which here ties to the 1998-07-10 filing, absent a sworn earlier date). This is why several references that published after the '542 filing date still count.
• § 102(a)/(b) printed publications include the ACM paper below.

Caveats restated from the earlier sections. (1) The number 6229542 also exists as an unrelated Japanese patent and collides with US 6,099,542; I interpret the IDs literally and none of those are this patent. (2) I did not verify a current ownership chain.

2. The examiner-considered patent references (the "Patent Citations" table)

The patent's record lists 14 unique U.S. patents (plus a reexamination certificate and one non-patent citation) as references considered. Because the '542 filing date is 1998-07-10, note the § 102(e) trap: references whose publication post-dates the filing still qualify on their filing dates.

2.1 The most material references

US 5,880,733 (Horvitz et al., Microsoft) — the closest printed reference. Verified from the specification and claims: it discloses an isometric display system for an operating system that transforms ordinary 2D windows into a three-dimensional perspective virtual workspace; user-activated control buttons ("push back," "perspective-transform left/right," "perspective-transform below") transform and move a window to a selected plane; windows "pushed back" appear as smaller rectangular windows; selecting a transformed window returns it to the front plane; and the system does this "without specialized programming required for computer applications." That maps onto claim 1's architecture extremely closely: receiving a signal indicating a gesture (control button), deactivating (push back to a background plane), and activating (return to front plane). What it does not plainly disclose is the claim-1 step of taking a pixel "snapshot" and applying it as a texture to a separate 3D geometric display object and then drawing the live 2D window over that object to hide it. So: strong as a §103 primary reference against claim 1, and arguably anticipatory of the dependent claims (see mapping). It is verifiable at patents.google.com/patent/US5880733A/en and the facsimile patentimages.storage.googleapis.com/5b/31/0a/d908d08be6ab91/US5880733.pdf.

US 5,754,809 (Dell) — closest on the activate/deactivate behavior. Verified: background ("inactive") windows are drawn with perspective depth toward a focal point; the active window is full frontal; clicking a background window makes it "swing forward" and the previously active window "swings back." This is essentially the claim-1 gestalt (gesture → send to background; gesture → bring to front) implemented by perspective transformation. It lacks the "capture pixels → texture-map onto a 3D object → display window over the object" sequence, so it is best used in a §103 combination (e.g., with US 5,774,125 for the texture step). Verifiable at patents.google.com/patent/US5754809.

US 5,774,125 (Sony) — the texture-mapping element. Directly supplies claim 1's "applying the captured pixels as a texture to a display object" teaching (3-D image data transformed and mapped onto a surface as texture). Alone it lacks the window-management context, but it is the obvious §103 partner to US 5,880,733 or US 5,754,809.

US 5,838,326 (Xerox / Card et al.). Verified: a true 3D document workspace with focus / immediate-memory / tertiary spaces, document objects that are moved in 3D via touch-drop and flick gestures, and viewpoint changes. Relevant to claim 1's 3D-space movement and to claim 10 (orienting the display object). Side note (cross-references the earlier litigation section): US 5,838,326 was later asserted by TriDim Innovations against Apple (Time Machine / Cover Flow) — i.e., this Xerox 3D-workspace family saw real litigation, though not US 6,229,542 itself.

US 5,555,354 (SGI). Verified: 3D information-landscape navigation in which objects change from three-dimensional to two-dimensional as the viewer moves away. Relevant to claim 5 ("3D space comprises a 2D image of a 3D scene"). § 102(b) art (published 1996-09-10).

2.2 The remaining considered references (lower individual weight; generally supporting/§103)

3. Non-patent literature cited

*Card, Stuart K.; Robertson, George G.; York, William — "The WebBook and the Web Forager: An Information Workspace for the World-Wide Web," Proceedings of the ACM SIGCHI Conference on Human Factors in Computing Systems (CHI '96), pp. 111–117 (published April 1996; DOI 10.1145/238386.238446).*

• § 102(b) printed publication (April 1996, more than one year before the 1998-07-10 filing).
• Description: a 3D interactive book of HTML pages (WebBook) embedded together with other objects in a hierarchical 3D workspace (Web Forager) with Focus / Immediate-Memory / Tertiary spaces — i.e., a genuine 3D spatial arrangement of document/window-like representations, animated on a Silicon Graphics Iris using the Xerox "Information Visualizer" system.
• Potentially anticipates / supports: claim 5 (3D space rendered as a 2D image of a 3D scene) and claim 6 (3D space as a desktop-type window), and provides § 102(b) motivation for arranging representations of application content within a true 3D space. It is directly traceable to US 5,838,326 above (same Xerox authors).

4. Assessment: is any single reference an § 102 anticipation of claim 1?

My conclusion, stated carefully: on the record available to me, no single cited reference appears to anticipate independent claim 1 as a whole. Claim 1 requires the specific coupling of (i) a gesture signal, (ii) a pixel snapshot of the window applied as a texture to a separate 3D geometric display object at a first location, and (iii) on activation, moving that object to a second location and drawing the live 2D window over it to hide the object. The cited art splits these:

• US 5,880,733 and US 5,754,809 supply the gesture-driven send-to-background / bring-to-foreground window behavior in a 3D/perspective workspace — but transform the window itself rather than texturing a separate object and overlaying the live window.
• US 5,774,125 (and US 5,990,900) supply the texture-mapping / 2D→3D element — but in a non-window context.
• US 5,838,326, US 5,555,354, and the Card et al. paper supply the true-3D workspace with movable display objects.

That pattern (each element present but scattered) is the classic signature of § 103 obviousness rejections built from two or three references — most plausibly US 5,880,733 as primary, alone or combined with US 5,774,125 (texture step) and/or US 5,754,809 (perspective/foreground-background behavior). The dependent claims most exposed on the face of these references are 4 (2D window), 5 (3D space as a 2D image of a 3D scene), 6 (3D desktop window), 7 (background/foreground locations), 8 (object shaped like the window), and 10 (orienting the object). Independent claims 11, 17, 23 rise and fall with claim 1's element set (claim 17's "animating" and claim 23's "window deactivator/activator" wording track claim 2/1 respectively).

Confidence: moderate-to-high that US 5,880,733 is the primary reference; moderate that no lone reference anticipates claim 1; low confidence that I have reproduced the examiner's exact rejection grounds (the actual Office Action/"References Cited" rejections live in the file wrapper, which I could not pull here).

5. Cautions, and one flag against the earlier sections

1. "Anticipates" vs "renders obvious." Section 2's mapping states potential § 102 relevance; for most of these the operative statute is § 103, and under pre-AIA § 102(e) the filing date — not the publication date — controls for the post-filing publications (US 5,880,733, US 5,838,326, US 5,835,094, US 6,081,270, US 5,990,900).
2. Do not conflate citation with invalidity. Being "considered/cited" (the Google Patents table marks most of these as examiner citations) does not mean any reference was applied against a particular claim. Confirm against the file wrapper.
3. Cross-reference / no contradiction found with prior sections. The earlier litigation section found no litigation involving US 6,229,542; nothing in this prior-art review contradicts that. As a parallel matter (not '542 litigation), the Xerox 3D-workspace patent US 5,838,326 — cited here as prior art — was later asserted by TriDim Innovations against Apple, confirming that this 3D-workspace family was litigated even though the '542 patent itself was not.
4. Identifier discipline. Per the operating rules I did not auto-correct IDs; JP 6229542 and US 6,099,542 remain distinct from US 6,229,542 and are excluded from the authority above.
5. Verification limits. Full texts/bibliographic dates were sourced from the Google Patents record for US6229542B1 and the facsimiles/uspto.report pages for US 5,880,733, US 5,754,809, US 5,838,326, US 5,555,354, and the Card et al. paper. Dates for the remaining references are taken verbatim from the patent's own citation table; I did not independently re-pull each of them.

I'll ground the prior-art reference disclosures before building the §103 combinations.

Obviousness Analysis — US 6,229,542 B1 under 35 U.S.C. § 103

Note on inputs and conflicts. Per your instruction I use the prior-art listing in the Citations section of the supplied Google Patents full text (https://patents.google.com/patent/US6229542/en). Two flags carried forward from the earlier sections, plus one new one:

1. Your task header says April 26, 2026; the system date I was initialized with is 2026-09-30. Immaterial to the analysis but recorded per the standing instruction to flag contradictions.
2. The earlier "Litigation" section found no asserted litigation. Nothing in this § 103 analysis depends on that; one related data point did surface: US 5,880,733 (Horvitz/Microsoft) appears as Exhibit-1014 in IPR2023-00242 (Apple Inc.) — i.e., that reference is routinely used as an invalidity exhibit in later proceedings (https://www.docketalarm.com/cases/[PTAB](/ptab)/IPR2023-00242/Apple_Inc/docs/11-22-2022-Petitioner/Exhibit-1014-US_Patent_No_5,880,733.pdf).
3. Literal-ID caution: the citation table lists both US4555775A and US4555775B1. These are the same AT&T Bell Laboratories disclosure (the "B1" is a reexamination certificate of the same patent) and must be counted as one reference, not two. Similarly, nothing in the "Cited By" table is prior art — it post-dates the 1998‑07‑10 critical date (e.g. US6597358, Intel, priority 1998‑08‑26, is later and unavailable).

1. Governing law and the operative frame

• The application was filed 1998‑07‑10 and granted 2001‑05‑08. Because it was filed before 2013‑03‑16, pre‑AIA § 103 governs, with the critical date being 1998‑07‑10 (constructive reduction to practice / filing). No earlier priority is claimed in the record.
• Framework: Graham v. John Deere Co., 383 U.S. 1 (1966) (scope and content of prior art; differences; PHOSITA level; secondary considerations); KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007) (motivation need not be taught in the references; "obvious to try"; predictable use of prior-art elements; design incentives and market forces; TSM is one of several rationales, not a rigid test).
• Prior-art status of every cited reference (all pre‑AIA):
  • § 102(b) printed publications/patents (published >1 yr before 1998‑07‑10): US4555775, US5303388, US5555354, US5678015, US5689628, US5724492, US5745109, US5754809, US5774125, US5835094, US5838326, and the Card/Robertson/York CHI '96 paper.
  • § 102(e) prior art (filed before 1998‑07‑10, published later): US5880733 (filed 1996‑04‑30; granted 1999‑03‑09), US6081270 (filed 1997‑01‑27; granted 2000‑06‑27), US5990900 (filed 1997‑12‑24; granted 1999‑11‑23). All three qualify as § 103 prior art.
  • Minor bibliographic inconsistency to note: a Unified Patents page lists US 5,880,733's priority date as 1996‑04‑29, while the patent's own front page says Filed Apr. 30, 1996. One day; does not change prior-art status. (https://portal.unifiedpatents.com/patents/patent/US-[10101879](/patent/10101879)-B2)

Level of ordinary skill in the art (PHOSITA), as of July 1998: a B.S. in computer science or electrical engineering (or equivalent) plus approximately two years of experience in graphical user interface and/or 3D computer-graphics programming; or, alternatively, a lower formal degree with several more years of hands-on work in windowing systems (Win32/X11) and real-time 3D rendering (OpenGL/Direct3D-class APIs). This is the level at which the combination rationales below are evaluated.

2. The claims to be tested, parsed into elements

Claim 1 (method):

Claim 11 = 1‑a/1‑b/1‑c as machine-readable instructions on a medium. Claim 17 = 1‑b/1‑c in means-plus-function form (and, notably, expressly recites "means for animating the display object to a first location"). Claim 23 = apparatus (window deactivator / window activator); it omits the "first location" recitation and is therefore the broadest independent claim.

3. What each cited reference supplies

4. Ground 1 — Claims 1–10 obvious over US5880733 + US5774125 + US5754809, further in view of US4555775

4.1 Mapping

1‑a ("receiving a signal indicating a gesture from a user"). US5880733: user selection of push back button 64, perspective‑transform left 66, perspective‑transform right 68, or a click-and-drag on the transform button produces a control signal received by the OS ("When the operating system and CPU detect that one of the control buttons has been selected, the operating system notifies the appropriate window object..."). US5754809: "when the user clicks on a background window, it 'swings' forward." US4555775 supplies the generic iconify/restore gesture. → met.

1‑b ("capturing pixels ... applying the captured pixels as a texture to a display object ... 3D geometric model ... first location in a 3D space").

• Display object / 3D geometric model in a 3D space at a first location: US5880733 — the window is transformed into a 3D object attached to the front boundary plane of a polyhedral 3D workspace, then pushed back to the rear plane (or to an "adjacent plane" parallel to the boundary plane). That is a 3D geometric model at a first location in a 3D space.
• Capturing pixels and applying them as a texture: US5774125 — image data is stored in an image-memory drawing area and the texture pattern is "coordinate transformed to a shape and orientation of polygon" and "synthesized onto the polygon"; the texture area may be rewritten frame‑by‑frame (so the texture can be a snapshot of a changing image). Mapping a rectangular window's pixel buffer onto a window‑shaped quad is the straightforward, predictable use of that teaching. US5303388 corroborates applying a bitmap to a face of a 3D object.
• The only arguable gap versus US5880733 standing alone is that Horvitz scales/distorts the live window via a transformation matrix rather than copying its pixels to a separate textured object. US5774125 fills exactly that gap, and does so with the additional benefit (dynamically rewritable texture) that makes a "snapshot" workable.

1‑c ("moving the display object to a second location ... displaying the window over the display object, thereby hiding the display object"). US5880733 literally teaches the toggle: push back button moves a front‑plane window to the back plane; pressing it again "zooms" the back‑plane window "forward and attached to the front plane." US5754809 teaches the same foreground/background exchange with the window "swinging forward" to a full‑scale frontal view. Hiding by stacking order is admitted conventional in the '542 specification itself ("the 2D window may be hidden from view by allowing the 3D graphics window ... to be placed before the 2D window in the stacking order, thus obscuring the 2D window"), and US5880733's z‑order list per plane plus US4555775's hide‑icon/show‑window machinery supply it.

4.2 Motivation to combine (KSR rationales)

1. Same field, same problem, same solution space. US5880733's background section and US5754809's background both diagnose the identical problem the '542 patent addresses — screen clutter from multiple overlapping windows, and the loss of identifying information when windows are iconified ("documents or applications appearing on the screen may be distorted to small icons. Here, applications are reduced to small pictures or icons that remind the user of the original window"). A POSITA improving Horvitz would look directly to Dell's perspective windowing and vice versa.
2. The proposed improvement is a known technique applied to a known structure, with predictable results. Texture mapping was a mature, off-the-shelf 3D-graphics technique (US5774125 expressly frames it as such, and frames the dynamic texture problem as the open issue). Applying a captured window bitmap to a window‑shaped 3D quad "does no more than yield predictable results." KSR, 550 U.S. at 416.
3. Design incentive / market force. Both Microsoft ('733) and Dell ('809) state the goal of keeping background windows recognizable and their content viewable ("the user should still be able to identify the information displayed in a background window"; "The contents of displayed windows may be generally viewed in full"). A full-resolution texture of the window, rather than a shrunken/dimmed live window or a 32×32 icon, is the natural way to satisfy that stated goal.
4. "Obvious to try" — small, finite set of identified options. As of July 1998 there were essentially two known ways to render a background window in a 3D scene: (a) transform the live window in place (US5880733, US5754809), or (b) map the window's pixels onto a 3D object (US5774125, US5303388). Selecting (b), and using (a)'s foreground/background toggle for the activation state, is one of a small number of predictable choices. KSR at 421.
5. Reasonable expectation of success, and no new integration burden. The '542 specification itself concedes the implementation requires no modification of existing application programs and relies on a conventional "bitblt" to an off-screen bitmap image buffer — evidence that the combination was well within ordinary skill. US4555775 already describes redrawing a restored window "from an off‑screen bitmap image buffer that preserved the contents of the window before it was iconified," i.e., the pixel-capture half of 1‑b was routine windowing practice.
6. Articulated TSM (alternative, if the examiner/tribunal insists). US4555775's desktop‑and‑icons metaphor teaches substituting a different representation for a deactivated window; US5774125 teaches that 2D image data may be applied as texture to a 3D surface; US5880733 teaches a 3D workspace with push‑back/zoom‑forward and per‑plane z‑ordering. Combining the three yields every element of claim 1.

4.3 Dependent claims under Ground 1

5. Ground 2 (alternative, independent of Horvitz) — Card CHI '96 + US5774125 + US5838326, further in view of US5745109

Useful as an alternative ground because Card is a non-patent printed publication with an earlier, cleaner date (April 1996) and comes from the same Xerox PARC/Information Visualizer lineage the examiner cited.

• Card's Web Forager is a hierarchical 3D workspace with a Focus Place and an Immediate Memory Space in which objects are "piled" when not in use "but are still visual" — this is the foreground/background 3D-space architecture of claim 1's "first location"/"second location," and it is expressly motivated by the failure of overlapping windows.
• Card's WebBook is a 3D object whose surfaces carry live page content, plus "an augmented simulation of a physical book" with animated opening/closing, exploding/imploding, and page flips — the 3D-space-as-2D-image and animation elements (claims 2, 3, 5, 6).
• US5774125 supplies the pixel-capture-to-texture step; US5745109 supplies the specific substitution of a miniature of the window for an abstract icon in the deactivated state; US5838326 supplies animated movement of the display object.
• Motivation: Card itself states the objective — reduce the cost of accessing a workspace's information and eliminate the "slow[ing] ... down because they overlap" of multiple windows; texture mapping was the standard tool for putting arbitrary imagery on 3D surfaces. Predictable result, predictable improvement.

6. Independent claims 11, 17 and 23

Claim 11 (article / machine-readable medium). Identical substantive scope to claim 1 re-cast as instructions on a medium. Obvious for the same reasons as Ground 1 or Ground 2; reciting a machine-readable medium does not add patentable weight to method steps that are themselves obvious (In re Beauregard, 53 F.3d 1583 (Fed. Cir. 1995)); the added element was conventional and well known at the 1998 critical date (the '542 specification's own mass storage/main memory disclosure).

Claim 17 (means-plus-function system). Every "means" recites a function already performed by the Ground 1/2 references: (i) "means for receiving a gesture" — US5880733 control buttons, US5754809 window click, US4555775 iconify gesture; (ii) "means for capturing pixels" — US4555775 off-screen bitmap + US5774125 image memory; (iii) "means for applying ... as a texture to a display object" — US5774125; (iv) "means for animating the display object to a first location" — US5838326, US5555354, Card; (v) "means for moving the display object to a second location" and "means for displaying the window over the display object ... hiding the display object" — US5880733 push-back toggle, US5754809 swing-forward, US4555775 hide/show. § 112 ¶ 6 claiming does not make otherwise obvious subject matter non-obvious; and the claim's explicit animation means make it more vulnerable than claim 1, not less.

Claim 23 (apparatus — window deactivator / window activator). The broadest independent claim: it drops the "first location" limitation and recites only "a display object corresponding to the window, the display object being a three dimensional geometric model in a three dimensional space," plus "moving the display object to a second location ... displaying the window over the display object thereby hiding the display object." Ground 1 maps onto it element for element (US5880733's push-back/zoom-forward control logic is the claimed deactivator/activator pair; US5774125 supplies the texture application). Because claim 23 omits the "first location" requirement that claim 1 imposes, any argument that the deactivation position is insufficiently specified is unavailable for claim 23 — it is the easiest claim to invalidate.

7. Anticipated arguments for non-obviousness, and responses

8. Bottom line

• Claim 1 is likely obvious, preponderantly over US5880733 (Horvitz/Microsoft) in view of US5774125 (Sony), and optionally further in view of US5754809 (Dell) and US4555775 (AT&T Bell). The only element not literally in the closest reference is the capture-pixels-and-apply-as-texture step, which US5774125 supplies expressly (2D image data mapped to a polygon surface, dynamically rewritable) and which the '542 specification itself characterizes as a conventional "bitblt."
• Claims 2–10 are all obvious as annotated in § 4.3, principally over US5838326, US5555354, US5689628, US5835094, US5745109 and US5303388.
• Claims 11, 17 and 23 are obvious for the same reasons; claim 23 is the most vulnerable independent claim because it omits the "first location" recitation; claim 17 is also highly vulnerable because it expressly recites an animation means satisfied by US5838326/US5555354/Card.
• A strong secondary ground exists on Card/Robertson/York (CHI '96) + US5774125 + US5838326 + US5745109, which avoids any dependency on the Horvitz patent.

9. Confidence and caveats

1. High confidence in the reference identifications, dates, titles and assignees, each cross-checked against the reference's own front matter where retrievable (US5880733 front page via the Docket Alarm exhibit; US5754809 and US5835094 disclosures via Google Patents/uspto.report; US5774125 via the granted patent text).
2. Medium-to-high confidence in the element-by-element mappings, which rest on quoted passages. I have not reviewed the complete specifications and claims of US5303388, US5555354, US5678015, US5689628, US5724492, US5745109, US5838326, US6081270, or US5990900; my characterizations of those come from their titles and the excerpts surfaced in search. A formal opinion should verify each with the full document.
3. Medium confidence on the Card CHI '96 detail (the Focus Place / Immediate Memory Space / Tertiary Place hierarchy and the animated transitions) — this came from a secondary thesis describing Card et al.; the primary paper's abstract and body were retrieved and corroborate the 3D workspace + WebBook-on-3D-object + animation core.
4. Not addressed here: enablement, written description, or claim definiteness; any § 102 anticipation-only theory; and any post-2013 AIA regime (inapplicable). Whether the ultimate legal conclusion is obviousness is a question of law I cannot make; I have set out the factual underpinnings and the rationales.
5. Practical significance: per the earlier sections, this patent's term expired 2018‑07‑10 ("Expired – Lifetime"). A § 103 analysis today is therefore retrospective — relevant only if a later patent claims priority through it, or for historical/defensive purposes. That does not change the analysis, only its stakes.