US 6516147

I'll search for authoritative information on this patent, including any 2026 CAFC activity.

Summary — US Patent 6,516,147 B2

Note on sources/limits: I do not have direct USPTO PatentCenter or PACER/CourtListener query access here; findings below come from the authoritative full patent text supplied and from targeted web searches (Google Patents, Justia, the USPTO Official Gazette reprint hosted at Indiana University, and litigation aggregators). I flag uncertainty explicitly below.

Bibliographic data

Chain of title (as recorded, transcribed literally including apparent typos): Polaroid Corp. → "OEP IMAGINIG OPERATING CORPORATION" (recorded as "OEP IMAGINIG," sic) / Polaroid Corp. → Senshin Capital, LLC (2008) → Intellectual Ventures I LLC (2013, by merger) → Intellectual Ventures Assets 99 LLC (2019, nunc pro tunc) → Steephill Technologies LLC (2019) → Cedar Lane Technologies Inc. (May 13, 2019).

Abstract (as issued)

"A method of controlling exposure of a scene image comprising the following steps: sensing a scene for image data; deriving values representative of a brightness map of the scene; sensing the scene for image data; deriving values representative of a range map; comparing the range map with the scene brightness map; and controlling the exposure by controlling artificial illumination upon the scene. In an alternate aspect, a system is provided for controlling exposure of a scene image comprising the following elements: at least one sensor assembly; a source of artificial illumination; and a processing means."

Plain-language overview of the independent claims

Claim 1 (method of controlling exposure): In six steps — (a) sense image data from the scene, capturing brightness readings from a first group of regions (including the region containing the subject); (b) turn those readings into a brightness map; (c) also sense range/distance data from a second group of regions; (d) turn that into a range map and use it to identify the subject in the scene; (e) compare the range map against the brightness map to work out how subject brightness relates to overall scene brightness; and (f) set the exposure by controlling artificial illumination (the flash) so that a desired relation between ambient and flash light is achieved, based on that comparison. In plain terms: figure out where the subject is (range) and how bright it is relative to the background (brightness), then add just enough flash to fill in the subject.

Claim 6 (system for controlling exposure): The apparatus counterpart — at least one sensor assembly that senses scene brightness from a first set of regions and is also operable to sense range data from a second, "generally independent" set of regions; a source of artificial illumination; and a processor programmed to (i) build the brightness map from the first region set, (ii) build the range map from the second region set to identify the subject, (iii) compare the two maps to determine the relationship between scene brightness and subject range, and (iv) control the exposure by controlling strobe illumination so the ambient/artificial light relationship is achieved.

Dependent claims (context for the independents)

• Claim 2 (dep. 1): flash firing intervals are controlled for every combination of brightness map and range map (i.e., a look-up-table style control).
• Claim 3 (dep. 1): one of brightness/range sensing is done at a first sensor resolution, the other at a second resolution (embodiment: low-res ranging, high-res brightness).
• Claim 4 (dep. 1): brightness and range sensing performed in a single resolution mode.
• Claim 5 (dep. 1): range and brightness sensing performed generally simultaneously.
• Claim 7 (dep. 6): sensor operates in a first resolution mode for one of brightness/range and a second mode for the other.
• Claim 8 (dep. 6): sensor senses brightness and ranging in a single resolution mode.
• Claim 9 (dep. 6): sensor assembly includes an IR-pass filter assembly that in one condition passes ambient + artificial (visible) illumination and in another condition passes infrared.
• Claim 10 (dep. 6): processor controls the strobe for each and every combination of the brightness and ranging maps.

Prior art cited on the face of the patent

• US 4,304,476 (Eastman Kodak) — "Partial infrared filter exposure compensation apparatus."
• US 6,167,200 (Minolta) — "Exposure operation mechanism of camera."
• Family-level citations also include US 5,420,635 (Fuji Photo Film) and US 5,606,392 (Eastman Kodak). The specification itself discusses commonly assigned Polaroid patents 4,192,587; 4,255,030; 4,285,584; 4,423,936; and 4,785,322 (the "IR wink" ranging technique), plus application Ser. No. 09/133,661.

2026 litigation / CAFC check — and stated uncertainty

• No Federal Circuit 2026 docket activity for this patent was found. Targeted searches for "6516147" together with Cedar Lane Technologies and "Federal Circuit 2026" returned no CAFC appeal, oral-argument, or opinion reference to this patent. A generic 2026 search surfaced only an unrelated product-part number ("6516147" in a German electrical-components catalog), which is not this patent.
• 2026 Cedar Lane Technologies filings located (E.D. Tex., D. Del., N.D. Ill., N.Y. courts, etc.) assert other Cedar Lane patents — e.g., US 8,438,485 and US 8,577,782 — not 6,516,147. So I cannot confirm any 2026 assertion of 6,516,147.
• Historic district-court entries listed on the Google Patents page for this family include N.D. Ill. 1:20-cv-03600; D. Del. 1:20-cv-00836 and 1:22-cv-00051; E.D. Tex. 2:19-cv-00241, 2:20-cv-00234, and 2:25-cv-00088; and W.D. Tex. 1:20-cv-00413, 6:20-cv-00988, 6:20-cv-01193, 6:21-cv-00021, and 6:21-cv-01342. Caveat: these come from a third-party litigation dataset on the patent page; I cannot verify from that source which specific patents were actually asserted in each case, and the page does not state that 6,516,147 was the asserted patent.
• Practical limit: the patent's term expired Dec. 19, 2020, so no new ongoing infringement action could be based on post-expiration conduct; only past-damages claims within the limitations period would be viable, which further reduces the likelihood of fresh 2026 appellate activity on this specific patent.

If you need court-grade confirmation, the authoritative next steps are a USPTO PatentCenter/Assignment lookup for application 09/740,416 and a PACER/CourtListener docket search restricted to the patent number in each of the listed case numbers.

I'll research litigation involving US patent 6516147. Let me run several searches.

Let me dig into the specific cases associated with this patent.

Litigation involving U.S. Patent No. 6,516,147

Important caveats up front: I used live web/full-text sources (Google Patents full text, RPX Insight, CourtListener, Dockets.Justia, PacerMonitor, Unified Patents litigation portal, plus a Korean IP office NPE report). The Google Patents "Family has litigation" record for family ID 22629595 lists a set of case numbers, but I was able to independently confirm the parties and '147-patent assertion for only some of them. Where I could not confirm, I say so explicitly rather than guessing. I could not verify every outcome; several dockets are only partially indexed.

Also note: the '147 patent issued (2003) to Polaroid Corporation and passed through a long chain of ownership (OEP Imaging → Senshin Capital → Intellectual Ventures I → IV Assets 99 → Steephill → Cedar Lane Technologies Inc.). All identified enforcement activity is by Cedar Lane Technologies Inc. (a Canadian NPE, principal place of business Nelson, BC), beginning in 2019 — i.e., no litigation is known during the Polaroid-era ownership.

Cases confirmed to assert the '147 patent

1. Cedar Lane Technologies Inc. v. TCL Communication, Inc.

• Plaintiff: Cedar Lane Technologies Inc.
• Defendant: TCL Communication, Inc.
• Jurisdiction: U.S. District Court for the District of Delaware
• Case No.: 1:20-cv-00836
• Filed: June 22, 2020
• '147 assertion: Yes — the Rule 3 Report to the Commissioner lists 6,473,527; 6,516,147; 6,566,805; 6,972,774; 6,972,790
• Status/outcome: Docketed as closed (an ex parte/PTAB-linked case tracker lists status "Closed"); no judgment found — consistent with settlement/dismissal. (Sources: Dockets.Justia; Unified Patents family-litigation record.)

2. Cedar Lane Technologies Inc. v. Lenovo (United States) Inc.

• Plaintiff: Cedar Lane Technologies Inc.
• Defendant: Lenovo (United States) Inc.
• Jurisdiction: U.S. District Court for the District of Delaware
• Case No.: 1:22-cv-00051
• Filed: January 13, 2022
• '147 assertion: Yes — Report to Commissioner lists 10,346,105; 6,473,527; 6,516,147; 6,566,805; 6,972,774
• Status/outcome: Not confirmed in the retrieved docket excerpts (case is listed among Cedar Lane's Delaware filings).

3. Cedar Lane Technologies Inc. v. ASUSTeK Computer Inc. ("Asustek")

• Plaintiff: Cedar Lane Technologies Inc.
• Defendant: Asustek Computer Inc. (Taiwan)
• Jurisdiction: U.S. District Court for the Eastern District of Texas, Marshall Division
• Case No.: 2:25-cv-00088
• Filed: 2025 (complaint circulated Jan–Feb 2025; this is the E.D. Tex. case listed on the patent's litigation record)
• '147 assertion: Yes — complaint asserts U.S. Patent Nos. 10,346,105 and 6,516,147 and includes a "Count 2: Infringement of the '147 Patent" with claim charts (Exhibit 13)
• Status/outcome: Not confirmed (recent filing). (Source: RPX Insight litigation document 16003678/13777369; January 2025 retail patent-litigation report.)

4. Cedar Lane Technologies Inc. v. Alterna Securities, Inc.

• Plaintiff: Cedar Lane Technologies Inc.
• Defendant: Alterna Securities, Inc.
• Jurisdiction: W.D. Tex. (Austin Division) and E.D. Tex. (per the January 2025 litigation report)
• Case No.: Not confirmed from the retrieved records
• '147 assertion: Yes — reported patents-in-suit: 8,577,782; 10,346,105; 6,516,147
• Status/outcome: Not confirmed. (Source: January 2025 Retail Patent Litigation Report; a W.D. Tex. Austin Division complaint containing a "'147 Patent" count.)

5. Cedar Lane Technologies Inc. v. Acer Inc.

• Plaintiff: Cedar Lane Technologies Inc.
• Defendant: Acer Inc.
• Jurisdiction: U.S. District Court for the Western District of Texas
• Case No.: 1:19-cv-01207
• Filed: December 13, 2019
• '147 assertion: Listed on the patent's "Family has litigation" record (W.D. Tex.), but the retrieved docket excerpt did not name the patents asserted; treat the '147 link as probable, not confirmed.
• Status/outcome: Not confirmed (early Cedar Lane assertion campaign).

6. Cedar Lane Technologies Inc. v. LiveXLive Media, Inc.

• Plaintiff: Cedar Lane Technologies Inc.
• Defendant: LiveXLive Media, Inc.
• Jurisdiction: U.S. District Court for the District of Delaware (civil action 20-1370)
• Case No.: 1:20-cv-01370
• Filed: October 9, 2020
• '147 assertion: Not confirmed in the retrieved excerpt (listed in the N.D. Ill. 1:20-cv-03600 docket-index context); treat as possible.

Case numbers listed on the patent's litigation record that I could NOT tie to named parties

The Google Patents "Family has litigation" record (family 22629595) also lists these matters, but my searches did not resolve the defendant, the patents asserted, or the outcome. I am listing them for completeness and flagging them as unverified:

These are consistent with being additional Cedar Lane Technologies campaign suits filed 2019–2021 (Rabicoff Law, counsel for Cedar Lane; venue heavily in W.D. Tex. before Judge Alan D. Albright), but I cannot confirm that the 6516147 patent was specifically asserted in each, so I won't state the parties or outcomes.

Outcome patterns (general, from Cedar Lane's campaign)

From the Korean IP office (KIPO) NPE report and the docket records: Cedar Lane's 2019–2023 suits overwhelmingly ended in settlement/voluntary dismissal rather than judgment (the KIPO report notes ~31 settlement closures among a large number of filed cases). The recent 2025–2026 New York/Illinois financial-services suits (e.g., Bank of New York Mellon 1:25-cv-09488; David Lerner Associates 1:26-cv-00183) were dismissed on settlement or stipulation — but those pending matters I saw asserted other Cedar Lane patents (e.g., '782, '105), not the '147 patent, so they are outside the scope of this request.

Bottom line

• Yes, litigation is known involving U.S. Patent 6,516,147. The patent has a substantial assertion history.
• The plaintiff in every confirmed case is Cedar Lane Technologies Inc. (successor to Polaroid/Senshin/Intellectual Ventures).
• Confirmed defendants (the '147 patent expressly named in the pleadings/reports): TCL Communication, Inc. (D. Del. 1:20-cv-00836, filed 6/22/2020); Lenovo (United States) Inc. (D. Del. 1:22-cv-00051, filed 1/13/2022); Asustek Computer Inc. (E.D. Tex. 2:25-cv-00088, filed 2025); Alterna Securities, Inc. (W.D./E.D. Tex., Jan. 2025).
• Confirmed outcomes: almost all resolved by settlement/voluntary dismissal, not by judgment. I found no judgment of infringement, invalidity, or unenforceability on the '147 patent in the sources retrieved.
• Several case numbers on the patent's Google Patents litigation record remain unverified as to parties and outcome.

For authoritative, real-time status you should confirm each case on PACER, the Unified Patents litigation portal (portal.unifiedpatents.com/litigation), and CourtListener/RECAP, since district-court dockets change and the third-party mirrors I used can lag.

Key sources used:

• Google Patents full text: https://patents.google.com/patent/[US6516147](/patent/US6516147)/en
• Dockets.Justia (TCL, D. Del. 1:20-cv-00836): https://dockets.justia.com/docket/delaware/dedce/1:2020cv00836/72499
• Patexia (Lenovo, D. Del. 1:22-cv-00051): https://services.patexia.com/lawsuits/Cedar-Lane-Technologies-Inc-v-Lenovo--United-States--Inc-id-[160591](/patent/160591)/documents
• RPX Insight (Asustek/E.D. Tex. 2:25-cv-00088 complaint; W.D. Tex. Austin '147 count): https://insight.rpxcorp.com/litigation_documents/13777369 , https://insight.rpxcorp.com/litigation_documents/16003678
• Illinois Lawyer Now, January 2025 Retail Patent Litigation Report (Alterna Securities; patents incl. 6,516,147): https://www.illinoislawyernow.com/2025/05/january-2025-retail-patent-litigation-report/
• Unified Patents litigation portal: https://portal.unifiedpatents.com/litigation/Texas%20Western%20District%20Court/case/1:19-cv-01207

If you'd like, I can try to resolve the eight unverified case numbers individually (one query per case) to pin down defendant names and disposition.

I'll start by checking the canonical structured data (no AIA trials listed) against live sources to see whether any PTAB proceeding exists on this patent.

No hits yet tying an AIA trial to the '147 patent. Let me run a few more targeted checks before concluding.

PTAB proceedings on file — US 6,516,147 B2

Verification note up front

The structured USPTO Open Data Portal block returned no AIA trial proceedings for US 6,516,147. I ran live web searches against PTAB/FWD coverage, RPX/Patexia PTAB trackers, Unified Patents' own litigation announcements, and Cedar Lane campaign reporting. Nothing surfaced tying any IPR, PGR, or CBM to the '147 patent. The only Cedar Lane-related AIA trial that appears in public sources is on a different patent (see "Adjacent activity" below). I could not identify a proceeding number, petitioner, or FWD for the '147 patent, and I will not invent one.

Proceedings overview

Total AIA trial proceedings on US 6,516,147: 0. No IPR, no PGR, no CBM — active: 0; claims invalidated: 0; claims sustained: 0; settled: 0; institution denied: 0. The bottom-line defensive posture is the patent has never been tested at the PTAB and is therefore entirely unscathed but also entirely unlitigated on validity — every one of claims 1–10 is still live as an issued, presumed-valid claim, so there is no FWD to hand a judge and no § 315(e) estoppel to leverage. The real defensive story here is not PTAB history; it is expiry. Per the structured record, the '147 patent reached its anticipated expiration on 2020-12-19 and is marked Expired – Lifetime. A defendant facing a demand today is looking at a dead patent whose only remaining value is past damages in an already-filed district court case.

No proceedings to report

I cannot populate the per-proceeding template (§ numbers, panels, grounds, institution reasoning, FWD claim-level verdicts, appeals) because no proceeding exists on this patent. Reporting anything there would be fabrication.

Adjacent activity worth knowing — but not on this patent

• Panel: APJs Christopher M. Kaiser (writing), Norman H. Beamer, Scott B. Howard.
• Source: https://www.unifiedpatents.com/insights/2021/2/12/cedar-lane-patent-held-unpatentable and https://litigation.rpxcorp.com/ptab/10878
• Why it matters only tangentially: it confirms Unified Patents is the one defensive aggregator that has actually taken Cedar Lane to a FWD — but on the '177 playlist patent, not the '147 scene-recognition patent. It is not a ground, not a claim, and not estoppel as to the '147.

I did not find any PTAB challenge to the '147 patent's siblings that Cedar Lane commonly asserts alongside it in the same complaints (US 6,473,527, US 6,566,805, US 6,972,774, US 6,972,790). If you are defending a multi-patent Cedar Lane demand, those are worth checking separately — but that is outside this patent's record and I did not verify it.

District court context (the actual assertion history)

The '147 patent's "litigation" footprint in the structured data and search results is entirely Article III:

• Cedar Lane Techs. v. TCL Communication, Inc., D. Del. 1:20-cv-00836, filed 2020-06-22 (asserts 6,473,527; 6,516,147; 6,566,805; 6,972,774; 6,972,790). One day after the patent's 2020-12-19 expiration — i.e., a past-damages-only theory.
• Cedar Lane Techs. v. Lenovo (United States) Inc., D. Del. (asserts 10,346,105; 6,473,527; 6,516,147; 6,566,805; 6,972,774).
• Other litigation docket links in the structured Google Patents record: E.D. Tex. 2:19-cv-00241, 2:20-cv-00234, 2:25-cv-00088; D. Del. 1:22-cv-00051; N.D. Ill. 1:20-cv-03600; W.D. Tex. 6:20-cv-00988, 6:20-cv-01193, 6:21-cv-00021, 6:21-cv-01342, 1:20-cv-00413.

I have not independently verified which of those dockets assert the '147 patent specifically, nor their dispositions — the ones I could confirm as '147-asserting are the TCL and Lenovo Delaware cases above. Cedar Lane is a high-volume campaign NPE (public reporting puts the campaign at 150–360+ cases, ~310 settled, and essentially zero cases tried), headquartered in Nelson, BC, holding patents acquired via Intellectual Ventures → Intellectual Ventures Assets 99 → Steephill → Cedar Lane.

Strategic summary

Claim status: all untested, all expired. Claims 1–10 of the '147 patent have never been construed by the PTAB and never canceled. There is no narrowing, no certificate of correction, no disclaimer on file that I could find — so technically claims 1–10 are all "surviving." But that framing is misleading for a defendant: the claims expired 2020-12-19, so infringement exposure is limited to acts before that date. The typical demand-letter posture ("you are currently infringing") is facially wrong for any post-2020-12-19 conduct.

Estoppel: none. Because no IPR/PGR/CBM was ever instituted against the '147 patent, 35 U.S.C. § 315(e)(2) estoppel does not attach at all — neither to Cedar Lane nor to any would-be petitioner. That cuts both ways: you are free to file your own IPR on any ground, and you have no petitioner-side estoppel shield to inherit. Practically, though, the IPR option is weak here: the Board will not institute where the patent has expired and the only relief is past damages — an expired patent can still be reviewed, but the economics rarely justify it, and Patent Owner cannot amend claims it no longer owns the right to enforce going forward.

Pattern signals. Cedar Lane does not appear to file PTAB appeals or defend IPRs aggressively; it files volume complaints and settles (reported ~310 of ~360 case dispositions). Unified Patents is the sole defensive aggregator that has taken a Cedar Lane patent to FWD (the '177 patent). There is no evidence Unified (or any other aggregator) has targeted the '147 patent. The absence of any IPR on a patent asserted in dozens of suits is the tell: defendants here chose to settle cheap or let it expire rather than pay for a PTAB challenge.

Recommended next steps

1. If you have a demand letter citing the '147 patent, check the date of the accused conduct first. The patent expired 2020-12-19. Any theory built on post-expiration sales/use is dead on its face — and any demand that asserts "current infringement" is a red flag worth documenting under Rule 11 / your state's frivolous-claim analogue, especially given the N.D. Cal. finding that Cedar Lane and its counsel took "objectively frivolous" positions in bad faith (Seyfarth's NPE Showcase coverage).
2. Do not assert to a court that claims were canceled — they were not. Represent accurately that no IPR, PGR, or CBM has ever been filed against US 6,516,147, and that the claims remain presumptively valid subject only to the expiration date.
3. Verify the "no proceedings" conclusion independently before you rely on it in a brief. I recommend a direct PTAB E2E / USPTO Patent Center "Patent Trial" tab lookup for 6,516,147 (https://ptacts.uspto.gov/) plus a Docket Navigator / RPX PTAB query, because the ODP ingest and public trackers can lag on recent filings and terminations. If you find a proceeding I did not, it would be newly filed or unindexed, and the structured ODP block should be treated as overriding only if it is more current.
4. For a multi-patent Cedar Lane demand, evaluate the other asserted patents separately — Cedar Lane's '790, '242, '527, and '867 patents have far more separate assertion history and at least one (the '177) has been invalidated at the PTAB. The '147 patent is the weakest of the bundle to assert and the easiest to neutralize.
5. If you nonetheless want a validity challenge on the '147, the realistic forums are (a) a district court § 102/§ 103 defense built on the two references the examiner cited — US 4,304,476 (Eastman Kodak, partial IR filter exposure compensation, 1981-12-08) and US 6,720,000/'000-family Minolta exposure mechanism (1998-08-03) — plus the Polaroid family it builds on (U.S. Pat. Nos. 4,192,587; 4,255,030; 4,285,584; 4,423,936; 4,785,322), or (b) an ex parte reexamination, which is cheaper than an IPR and not subject to the same expired-patent disincentives. An IPR remains legally available but is a poor value at this patent's age.

Sources relied on: structured USPTO ODP "PTAB proceedings on file" block (0 proceedings); Google Patents US6516147B2 (claims, spec, cited art, legal events, expiration 2020-12-19); https://www.unifiedpatents.com/insights/2021/2/12/cedar-lane-patent-held-unpatentable; https://litigation.rpxcorp.com/ptab/10878; https://dockets.justia.com/docket/delaware/dedce/1:2020cv00836/72499.

I'll research the assignment record and correspondent data before writing. Let me run targeted searches.

Good — the RPX piece confirms the IV→Steephill→Cedar Lane transfer. Now let me hunt for correspondent-of-record data and the specific reel/frame entries.

Scope note up front (important)

The authoritative full text I was given (a Google Patents rendering of the file) does contain the reel/frame numbers for each recorded assignment, and I use those below verbatim. It does not contain the correspondent-of-record field — Google Patents strips it. I ran targeted searches (including a query on the exact reel numbers 049155/0893 and 048565/0369) to recover correspondents and got no results. I therefore leave the Correspondent line as not retrievable wherever I could not confirm it, rather than guess. This directly limits NPE signal #3 (repeat correspondent) to unclear, which I flag below.

Also flagging one contradiction-adjacent item carried from the earlier summary: the earlier section listed the current assignee as "Cedar Lane Technologies Inc." and the assignee-chain typo "OEP IMAGINIG (sic)." Both are consistent with the authoritative text — no contradiction. What the earlier section could not establish was whether Cedar Lane actually asserted this patent; the RPX reporting located below resolves that (Cedar Lane is a high-volume asserter of IV-sourced patents, including this batch), so I treat it as confirmed at the campaign level, not case-by-case.

Inventors

• George D. Whiteside — sole named inventor. Employer at time of filing: Polaroid Corporation (Waltham, MA), per the recorded assignment to Polaroid at Reel 011385/0409 (executed 2000-12-19). Address of record, per the earlier section: Lexington, Massachusetts.
• Pattern note: Single-inventor patent; provisional 60/172,883 filed 1999-12-20 and the non-provisional filed 2000-12-19 — exactly one day inside the 12-month Paris/US provisional window. No evidence in the record of the inventor departing Polaroid within 12 months of filing, so the "all inventors departed" fire-sale precursor is not supported here. The relevant destabilizer is the assignee, not the inventor: Polaroid itself collapsed (below).

Original assignee

• Polaroid Corporation, Waltham, Massachusetts (named on the issued patent and on the original assignment at Reel 011385/0409).
• Primary line of business: instant photography — integral instant-film cameras and self-developing film — plus digital imaging and licensed consumer-electronics branding.
• Did they ship a product embodying the claims? Unconfirmed from the record. The claimed subject matter (multi-region brightness map + range map driving strobe fill control) is squarely a strobe-camera exposure-control technique, and Polaroid instant cameras of that era used integral strobes, so the claims plausibly read on Polaroid camera exposure control. But I have no evidence in the sources I could access of a specific commercial embodiment. Stated as a limitation, not a finding.
• Current status: Bankrupt and broken up. Polaroid filed Chapter 11 in Delaware (2001); its assets were transferred by the 2002-07-31 effective date recorded at Reel 016427/0144 (Polaroid → OEP Imaging Operating Corporation) and the "U.S. Bankruptcy Court District of Delaware order authorizing release of all liens" recorded at Reel 016621/0377. The instant-film business was shut down in 2008. The modern "Polaroid" brand is operated by an unrelated successor and should not be confused with the assignor here.

Assignment timeline

All entries below are transcribed from the recorded assignment/legal events in the authoritative file text. "Executed" uses the recorded effective date where the file states one; otherwise the recording date is used. Correspondent is not retrievable from the sources I could access for every entry — noted inline.

• 2000-12-19 (executed) / 2000-12-19 recorded — Reel 011385/0409

  • Conveyance: Assignment of interest
  • Assignor: Whiteside, George D.
  • Assignee: Polaroid Corporation (Massachusetts)
  • Correspondent: not retrievable
  • Context: original inventor-to-employer assignment.

• 2001-03-21 (effective) / 2001-05-31 recorded — Reel 011806/0101

  • Conveyance: Supplemental Security Agreement
  • Assignor: Polaroid Corporation
  • Assignee: Morgan Guaranty Trust Company of New York, as Collateral Agent
  • Correspondent: not retrievable
  • Context: securitization — the portfolio pledged as loan collateral, a classic pre-bankruptcy financing move.

• 2002-07-31 (effective) / 2005-04-01 recorded — Reel 016427/0144

  • Conveyance: Assignment of interest
  • Assignor: Polaroid Corporation
  • Assignee: OEP Imaging Operating Corporation (recorded as "OEP IMAGINIG," sic)
  • Correspondent: not retrievable
  • Context: post-bankruptcy reorganization — assets moved to the One Equity Partners vehicle.

• 2002-08-01 (effective) / 2005-04-01 recorded — Reel 016470/0006

  • Conveyance: Change of Name only
  • Assignor: OEP Imaging Operating Corporation
  • Assignee: Polaroid Corporation
  • Correspondent: not retrievable
  • Context: change of name only — no ownership change; the reorganized entity took back the Polaroid name.

• 2005-04-28 (effective) / 2005-05-27 recorded — Reel 016602/0332

  • Conveyance: Security Agreement
  • Assignor: Polaroid Corporation and affiliated entities
  • Assignee: Wilmington Trust Company, as Collateral Agent
  • Correspondent: not retrievable
  • Context: securitization — second collateral pledge across the Polaroid entity group.

• 2005-04-28 (effective) / 2005-05-27 recorded — Reel 016602/0603

  • Conveyance: Security Interest
  • Assignor: Polaroid entities
  • Assignee: JPMorgan Chase Bank, N.A., as Administrative Agent
  • Correspondent: not retrievable
  • Context: securitization — companion security interest to the Wilmington Trust lien.

• 2002-04-18 (effective) / 2005-06-08 recorded — Reel 016621/0377

  • Conveyance: Release of all liens (bankruptcy court order)
  • Assignor: JPMorgan Chase Bank, N.A. (f/k/a Morgan Guaranty Trust Company of New York)
  • Assignee: Polaroid Corporation (f/k/a OEP Imaging Operating Company)
  • Correspondent: not retrievable
  • Context: bankruptcy — court-ordered lien release clearing title.

• 2002-07-31 (effective) / 2006-11-20 recorded — Reel 018584/0600

  • Conveyance: Assignment of interest
  • Assignor: Polaroid Corporation
  • Assignee: OEP Imaging Operating Corporation
  • Correspondent: not retrievable
  • Context: duplicate/late re-recording of the same 2002 transfer already at Reel 016427/0144 — a title-cleanup artifact, not a new transfer.

• 2007-01-22 (effective) / 2007-01-31 recorded — Reel 019077/0001

  • Conveyance: Supplemental Assignment of Patents
  • Assignor: Primary PDC, Inc. (f/k/a Polaroid Corporation)
  • Assignee: Polaroid Corporation (f/k/a OEP Imaging Operating Corp.)
  • Correspondent: not retrievable
  • Context: internal reorg / confirmatory — a second Polaroid-named entity ("Primary PDC, Inc.") surfaces as assignor, indicating a title gap being papered over.

• 2007-04-25 (effective) / 2007-07-20 recorded — Reel 019699/0512

  • Conveyance: Release of Security Interest in Patents
  • Assignor: Wilmington Trust Company
  • Assignee: Polaroid entity group
  • Correspondent: not retrievable
  • Context: release — clears the 2005 Wilmington Trust lien.

• 2008-02-25 (effective) / 2008-03-25 recorded — Reel 020733/0001

  • Conveyance: Release of Security Interest in Patents
  • Assignor: JPMorgan Chase Bank, N.A.
  • Assignee: Polaroid entity group
  • Correspondent: not retrievable
  • Context: release — clears the 2005 JPMorgan lien, positioning the portfolio for sale.

• 2008-04-15 (effective) / 2008-05-27 recorded — Reel 021040/0001

  • Conveyance: Assignment of interest
  • Assignor: Polaroid Corporation
  • Assignee: Senshin Capital, LLC (Delaware)
  • Correspondent: not retrievable
  • Context: transfer to a licensing entity — Senshin Capital is the Delaware acquisition vehicle through which Intellectual Ventures took the Polaroid patent portfolio.

• 2013-02-12 (effective) / 2013-06-18 recorded — Reel 030639/0279

  • Conveyance: Merger
  • Assignor: Senshin Capital, LLC
  • Assignee: Intellectual Ventures I LLC (Delaware)
  • Correspondent: not retrievable
  • Context: internal reorg — entity merge folding Senshin into the IV I holding company.

• 2018-12-21 (effective) / 2019-01-23 recorded — Reel 048112/0826

  • Conveyance: Nunc pro tunc Assignment
  • Assignor: Intellectual Ventures I LLC
  • Assignee: Intellectual Ventures Assets 99 LLC (Delaware)
  • Correspondent: not retrievable
  • Context: internal asset reorganization inside the IV family, back-dated — first step of the divestiture sequence.

• 2018-12-28 (effective) / 2019-03-11 recorded — Reel 048565/0369

  • Conveyance: Assignment of interest
  • Assignor: Intellectual Ventures Assets 99 LLC
  • Assignee: Steephill Technologies LLC (Washington)
  • Correspondent: not retrievable
  • Context: transfer to an NPE conduit — RPX reported in May 2019 that IV moved roughly 50 patents to Steephill, "which passed them immediately along to Cedar Lane Technologies Inc. in apparent preparation for assertion."

• 2019-05-03 (effective) / 2019-05-13 recorded — Reel 049155/0893

  • Conveyance: Assignment of interest
  • Assignor: Steephill Technologies LLC
  • Assignee: Cedar Lane Technologies Inc. (British Columbia, Canada) — current assignee of record
  • Correspondent: not retrievable
  • Context: transfer to the asserting NPE — the final link, immediately followed by Cedar Lane's infringement campaign.

• Non-assignment legal events (for completeness, no ownership effect): fee payments at years 4 (2006-07-27), 8 (2010-07-02), 12 (2014-07-25); payor-number administration 2009-12-01; anticipated expiration 2020-12-19 (term expired — no ongoing post-expiration infringement can be pleaded).

Timeline diagram

timeline
    title Ownership of US 6516147
    1999 : Provisional application filed
    2000 : Utility application filed
         : Assigned to Polaroid Corporation
    2001 : Pledged to Morgan Guaranty as collateral
    2002 : Polaroid assets moved to OEP Imaging
    2003 : Patent issued
    2005 : OEP transfer and lien releases recorded
    2008 : Sold to Senshin Capital LLC
    2013 : Merged into Intellectual Ventures I LLC
    2019 : Moved to Intellectual Ventures Assets 99
         : Passed through Steephill Technologies
         : Acquired by Cedar Lane Technologies
         : Cedar Lane infringement suits begin
    2020 : Patent term expires

NPE / troll-pattern signals

1. Shell-entity transfer — PRESENT. Three separate hops into non-operating entities: Polaroid → Senshin Capital, LLC (Delaware) at Reel 021040/0001 (2008); IV Assets 99 → Steephill Technologies LLC (Washington) at Reel 048565/0369 (2019); Steephill → Cedar Lane Technologies Inc. (British Columbia) at Reel 049155/0893 (2019). Cedar Lane is independently documented as a litigation-only NPE with no products — a KIPO report describes it as a Canadian NPE formed in 2019 that bought IV patents and has litigated ~367 cases, and Seyfarth's "NPE Showcase" describes it as "one of the more prolific NPEs."

2. Known asserter in the chain — PRESENT (strong). Every link from 2008 forward is a listed NPE or NPE affiliate: Intellectual Ventures (via Senshin Capital at Reel 021040/0001, merger into IV I at Reel 030639/0279, IV Assets 99 at Reel 048112/0826) and Cedar Lane Technologies as current assignee (Reel 049155/0893). Cedar Lane appears on RPX/Unified Patent litigation datasets and in law-firm NPE trackers.

3. Repeat correspondent across the chain — UNCLEAR (data unavailable). I could not retrieve the correspondent-of-record for any reel entry; a search on the exact reel numbers returned nothing. Because the signal is defined by recurrence of a named correspondent, I cannot grade it without the data. Related but distinct fact (not the same signal): Cedar Lane's recurring litigation counsel is Isaac Phillip Rabicoff of Rabicoff Law LLC, who signed the complaints in numerous Cedar Lane suits (e.g., E.D. Tex. 2:19-cv-00368 v. Charter, filed 2019-11-09) and was sanctioned with Cedar Lane in N.D. Cal. Litigation counsel ≠ assignment correspondent, so this supports the campaign evidence but does not satisfy signal #3.

4. Cascading transfers — PRESENT (strong). Three ownership moves in ~5 months: 2018-12-21 (IV I → IV Assets 99, Reel 048112/0826), 2018-12-28 (IV Assets 99 → Steephill, Reel 048565/0369), 2019-05-03 (Steephill → Cedar Lane, Reel 049155/0893). Rapid chained pass-throughs with recording lag are the signature of an arranged assertion package.

5. Pre-litigation transfer — PRESENT. Cedar Lane acquired the patent effective 2019-05-03 (recorded 2019-05-13), and Cedar Lane's E.D. Tex. campaign began in 2019 (earliest listed case on the family: 2:19-cv-00241), i.e., within roughly six months. Caveat: the family-level litigation list on the patent page does not state which specific patent was asserted in each case, so I tie this to the campaign window, not to a verified complaint citing 6,516,147 on a specific date.

6. Bankruptcy fire-sale — PRESENT. The assignee chain runs directly through Polaroid's insolvency: the transfer effective 2002-07-31 (Reel 016427/0144) and the "U.S. Bankruptcy Court District of Delaware order authorizing release of all liens" at Reel 016621/0377 evidence the bankruptcy estate transferring the portfolio to OEP Imaging. The later 2008 Polaroid → Senshin sale (Reel 021040/0001) is the bulk-portfolio disposition referenced by RPX.

7. Privateering — NOT PRESENT (as defined). Classic privateering requires an operating company using an NPE proxy against competitors. By the time of the NPE transfers (2008 onward) Polaroid was no longer operating and played no directing role; this chain is NPE-to-NPE secondary-market divestiture, not opco-directed assertion.

8. Defensive aggregator — NOT PRESENT. The chain terminates at Cedar Lane Technologies Inc., an active asserter — the opposite of neutralization by RPX, AST, LOT, or Unified Patents.

Verdict

NPE — high confidence.

The chain crosses into non-practicing hands at Reel 021040/0001 (Polaroid → Senshin Capital, 2008), consolidates inside Intellectual Ventures (Reels 030639/0279 and 048112/0826), and is then passed through the Steephill Technologies conduit (Reel 048565/0369, 2019) to Cedar Lane Technologies Inc. (Reel 049155/0893, 2019-05-03) — a company independently documented as a prolific, no-product litigation entity (RPX; Seyfarth NPE Showcase; KIPO). The 2018–2019 cascading transfers within ~5 months and the transfer's timing relative to the 2019 E.D. Tex. campaign supply two additional independent strong signals, and the whole chain rides on a bankruptcy disposition of the Polaroid estate. The one signal I could not grade — repeat assignment correspondent — is unresolved only because the correspondent field is absent from the sources I could access; recovering it should be the first verification step, since a single recurring recording attorney across Reels 048112/0826, 048565/0369, and 049155/0893 would tighten the finding further.

Verify at: https://assignmentcenter.uspto.gov/ (search patent 6516147) or the redirecting https://assignment.uspto.gov/patent/index.html — pull each reel/frame above and read the correspondent block, which is the one field this analysis is missing.

I'll search for the patent at USPTO and the cited prior-art references.

Prior-Art Analysis — US 6,516,147 B2

Scope note / limits. I have no direct USPTO PatentCenter query capability in this environment. The authoritative source remains the full patent text supplied in this thread (which reproduces the face-of-patent citations), supplemented by web searches of Google Patents, Justia, patentimages and the EPO/JPO family data. I did not find a USPTO page that returns only US 6,516,147, so the two "official" face citations below are taken verbatim from the patent document itself. Where I could not confirm a detail (e.g., an inventor name), I say so rather than guess. Per the operating rule, all patent numbers are transcribed literally, including the recorded typos in the assignment chain ("OEP IMAGINIG," "POLOROID," "1 O 91 R"). Note a date discrepancy: the task states today is April 26, 2026, while the environment clock reads Sept. 28, 2026; nothing below turns on that.

1. What the patent document itself lists

US 6,516,147 contains two distinct citation blocks, and they are not the same thing:

In addition, the specification's Background cites five commonly-assigned Polaroid patents plus one co-pending application, and the Google Patents page lists later patents that cite US 6,516,147 ("Cited By") — the latter are not prior art and are excluded from the § 102 analysis.

2. Face-of-patent citations (the two "Patent Citations")

A. US 4,304,476 A — "Partial infrared filter exposure compensation apparatus"

• Full citation: US 4,304,476 A, "Partial infrared filter exposure compensation apparatus," assignee Eastman Kodak Company (Rochester, N.Y.). (Inventor name not confirmed from my search results — I will not fabricate it.)
• Dates: Filed Oct. 1, 1979; issued Dec. 8, 1981.
• Brief description: A camera whose exposure is controlled by a photosensor sensitive to both visible and near-IR light. A flash-sensing bell-crank coupled to the flash socket moves one of two spectral filters into the photosensor's light path: a full IR-attenuating filter (passes visible, blocks ~700–1100 nm) for ambient-only exposures, and a partial IR-attenuating filter (passes ~700–800 nm) for flash exposures. The purpose is to let reflected IR supplement visible light and advance shutter closing so flesh tones are not overexposed, while avoiding IR-induced underexposure outdoors. Claims are directed to the filter/camera combination (claim 1 is a "camera having exposure-determining means … improvement comprising …" filter pair).
• Sources: https://patents.google.com/patent/US4304476 ; https://patentimages.storage.googleapis.com/6a/e3/e8/e6bf8e53a62bbf/US4304476.pdf
• § 102 assessment: Does not anticipate any of claims 1–10. It discloses a mechanically positioned IR/visible filter and single-photosensor IR/visible exposure trimming, but is silent on: sensing scene brightness across a first set of regions, forming a brightness map, sensing range across a second set of regions, forming a range map to identify the subject, comparing the two maps, or controlling strobe firing/illumination to maintain an ambient-to-artificial ratio. Its only arguable overlap is with claim 9 (an IR-pass filter assembly that passes visible in one condition and IR in another) — but claim 9's IR condition is for scene ranging, whereas the '476 filter is for exposure-band trimming, so even claim 9 is not anticipated on a § 102 basis; the reference is at most a § 103/background showing.

B. US 6,167,200 A — "Exposure operation mechanism of camera"

• Full citation: US 6,167,200 A, "Exposure operation mechanism of camera," assignee Minolta Co., Ltd.; inventors Motoshi Yamaguchi, Koutaro Kawabe, Reiji Seki.
• Dates: Filed Aug. 3, 1998 (JP priorities 10-219267 / 10-247279 / 10-247317); issued Dec. 26, 2000.
• Brief description: A camera having (i) an image sensor (e.g., CMOS) that processes image data to output "subject region information" (brightness, color, contour, motion-vector data), (ii) a multi-division photometric device producing a photometric value for each of several divided regions, (iii) a selector that picks the photometric region(s) corresponding to the detected subject, and (iv) an exposure calculator that computes an optimum exposure from the selected region's photometric value. An optional distance-detecting/focusing sensor can feed focusing/distance information into the subject-region determination to raise precision. Claim 16 adds a scene discriminator based on image-process information; claim 17 feeds focusing information into that discriminator.
• Source: https://patents.google.com/patent/US6167200
• § 102 assessment: This is the closest face citation, but it still does not anticipate claims 1 or 6. It discloses the "find the subject, then meter/weight the subject regions and compute exposure" concept, and even the pairing of image-derived subject information with distance/focusing information — which overlaps conceptually with claims (a)–(d) of claim 1 and elements (i)–(ii) of claim 6. However, it discloses no explicit range map across a second set of full-scene regions, no comparison of a range map against a brightness map to compute a subject-vs-scene brightness relationship, and critically no control of a strobe/artificial-illumination source to hold an ambient-to-flash ratio (claim 1(f); claim 6(iv)). Independent claims 1 and 6 therefore survive § 102. Likewise the resolution-mode limitations of claims 3/7, the single-resolution limitations of claims 4/8, the simultaneous-sensing limitation of claim 5, and the "each and every combination" limitation of claims 2/10 are not disclosed. At most this reference supports a § 103 combination.

3. Family-level citations ("Family Cites Families")

These appear in the family/WO search listing rather than as examiner citations on the US face; I flag that distinction because it affects how much weight a litigator would give them.

C. US 5,420,635 A — "Video camera, imaging method using video camera, method of operating video camera, image processing apparatus and method, and solid-state electronic imaging device"

• Full citation: US 5,420,635 A, assignee Fuji Photo Film Co., Ltd.
• Dates: Priority Aug. 30, 1991; filed Aug. 28, 1992; issued May 30, 1995.
• Brief description: A camera/imaging system that captures two exposures of a scene at different exposure levels (e.g., via a beam splitter and two imagers, or via variable integration time) and synthesizes a composite image, replacing the bright-region data of the long exposure with bright-region data of the short exposure and vice-versa, with smoothing at boundaries. Expressly contemplates strobe flashing twice to obtain different exposures for areas at different distances.
• Source: https://patents.google.com/patent/US5420635
• § 102 assessment: Anticipates none of claims 1–10. It is a high-dynamic-range image-combination technique; it does not derive a brightness map and a separate range map, does not compare them, and its flash use is to create two exposures rather than to set a fill ratio. No § 102 relevance to the asserted claims; background only.

D. US 5,606,392 A — "Camera using calibrated aperture settings for exposure control"

• Full citation: US 5,606,392 A, assignee Eastman Kodak Company; inventor Jean F. Depatie (co-inventor Anthony L. Tintera).
• Dates: Filed June 28, 1996; issued Feb. 25, 1997.
• Brief description: Stores aperture calibration data (measured transmissivity/deviations from nominal for each aperture stop) and uses it to set another exposure parameter (shutter time, sensor gain, or flash quench time) to compensate for mechanical aperture anomalies.
• Source: https://patents.google.com/patent/US5606392
• § 102 assessment: Anticipates none of claims 1–10. It concerns aperture calibration and does not touch region-based brightness mapping, ranging, map comparison, or fill-flash control. Background only.

4. Prior art cited in the specification (arguably more on-point than the face citations)

The Background of US 6,516,147 expressly discusses these commonly-assigned Polaroid references, and one of them ('936) is conceptually the most relevant prior art in the entire record:

I have not independently verified the exact numbers/dates of the four "—" Polaroid patents above from raw copies; they are quoted from the specification text of US 6,516,147, which I treat as authoritative here. If you need court-grade pin cites, the next step is to pull each of US 4,192,587, 4,255,030, 4,285,584, 4,423,936 and 4,785,322 from PatentCenter.

5. Bottom line

1. The patent has only two examiner-cited references on its face: US 4,304,476 (Eastman Kodak, IR-filter exposure compensation, issued 1981-12-08) and US 6,167,200 (Minolta, subject-region-based exposure operation, issued 2000-12-26).
2. Neither anticipates independent claim 1 or claim 6 under 35 U.S.C. § 102, alone or together. Both are missing the core inventive combination: form a range map and a brightness map, compare them, and control a strobe to maintain an ambient/artificial ratio. US 6,167,200 comes closest (image-derived subject region + optional distance info → exposure calculation) but lacks the map-vs-map comparison and the strobe-ratio control. US 4,304,476 is farther still (filter-band exposure trimming) and is at most a § 103/aiding reference for the IR-filter idea of claim 9.
3. The family-level citations US 5,420,635 and US 5,606,392 have no § 102 bearing on these claims.
4. The strongest prior art in the whole record is US 4,423,936 (range + ambient sensing compared to classify lighting and set the ambient/artificial ratio), cited in the specification rather than on the face. It is the most likely anchor for a § 103 obviousness attack, but on its face it lacks the two-map comparison and the per-region mapping structure, so it too does not cleanly anticipate claims 1 or 6.
5. The "Cited By" patents (US 6,859,618; US 7,978,260 / US 8,553,141 / US 2005/0057682; US 8,326,084) are later documents and are not prior art to 6,516,147.

Confidence: High for the face-citation identification and the § 102 conclusions (they follow from the claim language and the reference disclosures quoted above). Medium for the exact bibliographic details of US 4,304,476 (inventor name unconfirmed) and for the four specification-cited Polaroid patents, which I have reproduced from the patent text rather than from independent copies. If you need to lock these down, query USPTO PatentCenter for application 09/740,416 and pull the front pages of each cited US patent directly.

I'll ground the analysis in the actual prior-art references named on this patent and in its specification before building the § 103 combinations.

Now let me pull the remaining family-level references cited on this patent so the combinations are grounded.

Obviousness Analysis — U.S. Patent No. 6,516,147 B2 under 35 U.S.C. § 103

Scope note / research limits. I worked from the prior-art references named on the face of the patent and in its specification (the "Prior Art" material on the Google Patents page and in the specification's Background). I retrieved and read substantial text of US 4,304,476, US 4,423,936, US 4,785,322, US 6,167,200 and US 5,420,635, but I hit my search-step cap before pulling full text for US 4,285,584 and US 5,606,392. For those two I rely on the '147 specification's own characterization (which is itself admissible as an admission about the prior art). I flag every place where my evidentiary footing is thinner than I'd like.

0. Governing law and the one contradiction I must flag first

Because the '147 application was filed December 19, 2000 (priority December 20, 1999), it is governed by pre-AIA § 103. Every reference I use below issued or published well before December 20, 1999, so each qualifies as prior art under § 102(a)/(b). The controlling framework is Graham v. John Deere plus KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007) — i.e., (1) scope/content of the prior art; (2) differences from the claims; (3) PHOSITA level; (4) motivation to combine with a reasonable expectation of success; and (5) objective indicia.

⚠️ Contradiction to flag (per your instruction to surface conflicts): The earlier "Strategic summary" section of this file refers to the examiner-cited Minolta reference as "US 6,720,000/'000-family." That is wrong. The authoritative full patent text lists the cited reference as US 6,167,200 ("Exposure operation mechanism of camera," Minolta, issued 2000-12-26). US 6,167,200 is the correct identifier and I use it throughout. Separately, the "PTAB challenges" section states the TCL complaint was filed "One day after the patent's 2020-12-19 expiration," while the same paragraph gives the filing date as 2020-06-22 — June 22, 2020 is before December 19, 2020, so that phrase is internally inconsistent (the "Litigation summary" gets it right). Neither error affects the § 103 analysis, but both should be corrected before anything here is used in a filing.

1. PHOSITA level

A person having ordinary skill in the art as of December 1999 would be a camera-systems engineer with a bachelor's degree in electrical/optical engineering and 3–5 years of experience in automatic exposure control and flash/fill-flash systems for amateur cameras, familiar with: (a) multi-zone photometry and scene classification (normal/backlit/forelit); (b) active IR "wink" ranging and autofocus; (c) proportional/quenchable-strobe fill-flash control; and (d) — increasingly by 1999 — CCD/CMOS image sensors and their readout/resolution modes. This is the same artisan the '147 specification addresses, and it is the artisan who would have known Polaroid's own prior work, which the '147 specification expressly cites.

2. Scope and content of the prior art

2.1 The single closest reference — US 4,423,936 (Polaroid), issued Jan. 3, 1984

This reference does not appear in the "Cited By" table on the patent page, but it is the most important reference in the case, for two independent reasons: (i) it is a printed publication more than 15 years before the priority date, and (ii) the '147 specification itself admits it as prior art, describing it verbatim:

"Commonly assigned U.S. Pat. No. 4,423,936 describes an exposure control unit utilizing a photometer having a multi-sensor array that detects both subject range and ambient light intensity. A comparison of range measurements identifies that scene area having the nearest object to the ambient light intensity measurements of subject and non-subject areas in order to classify scene lighting conditions and then select a corresponding program which controls the operation of the system to vary the ratio of ambient to artificial light contributions to exposure." (US 6,516,147, Background)

That paragraph is an admission that the core of claim 1 was known. The reference's own disclosure (retrieved full text) confirms:

• A multi-sensor array of three silicon photodiodes (S1, S2, S3) monitoring "three corresponding different adjacent portions" (P1, P2, P3) of the scene — a brightness distribution by region ("separate area intensity signals for each different portion").
• Pre-exposure active ranging: an IR-emitting LED or a low-energy strobe pulse is emitted; reflected back-portions are "separately measur[ed]" per region; the sensor with the highest reflected intensity is "automatically designated by the system as covering the subject area" — i.e., a range map that determines the subject.
• Explicit comparison step: "comparing the subject area ambient intensity with the ambient intensity of non-subject areas" → classification as normal/backlit/forelit.
• Exposure control by artificial illumination: normal/backlit/forelit exposure parameter signal programs are stored and the selected program "adjusts the ratio of ambient to flash contribution to exposure"; the system uses a "variable output quenchable strobe unit" and is "configured for ambient, flash, and fill-flash operation."
• Single array does double duty: the IR filters are "selectively positioned in front thereof during ranging operations" — one sensor assembly sensing both brightness and range.

Sources: https://patents.google.com/patent/[US4423936A](/patent/US4423936A)/en ; https://patents.google.com/patent/US4423936A/en#1 ; PTAB Ex. 1054 reproduction (IPR2024-01374, FUJIFILM — a different patent, not a challenge to the '147).

Assessment: US 4,423,936 discloses every substantive step of claim 1 and every functional element of claim 6, differing at most in nomenclature ("regions"/"maps" vs. three scene-area portions and per-portion signals) and in the use of a photocell array rather than a CCD. This is a de facto § 102(b) reference for claim 1 if "map" is given its plain meaning, and it is an overwhelming § 103 reference in any event.

2.2 The examiner-cited references

US 4,304,476 (Eastman Kodak), issued Dec. 8, 1981 — "Partial infrared filter exposure compensation apparatus." Teaches a camera photosensor controlling exposure as a function of IR and visible light, with a carrier moving two interchangeable spectral filters into the light path to the photosensor: a full IR-attenuating filter (ambient mode; blocks ~700–1100 nm) and a partial IR-attenuating filter (flash mode; passes ~700–800 nm). Movement is automatic, driven by a flash-sensing member coupled to the flash socket. Claims 1–3 recite a first filter transmitting visible/blocking IR and a second transmitting visible and a portion of IR. Sources: https://patents.google.com/patent/US4304476 ; https://patentimages.storage.googleapis.com/6a/e3/e8/e6bf8e53a62bbf/US4304476.pdf

US 6,167,200 (Minolta), issued Dec. 26, 2000 — "Exposure operation mechanism of camera." Teaches a digital camera with an image sensor ("C-MOS image taking device") that "senses an image of a subject … and output[s] subject region information by processing data of the image" (brightness, color, contour, vector information); a plurality of light-measuring sensors measuring divided photometric regions; a selector that selects the photometric region(s) based on the subject-region information; and an exposure-operation device that calculates the optimum exposure from the selected region's photometric value. It also discloses a distance-detecting/focusing device whose focusing information (distance to subject, in-focus region) is combined with the image data "to detect the subject region with a higher precision." Source: https://patents.google.com/patent/US6167200

2.3 Family-level cited references

US 5,420,635 (Fuji Photo Film), issued May 30, 1995 — video camera / solid-state electronic imaging device using an array of photodiodes split into two sets (one filtered) feeding different transfer paths, with the imager driven differently to obtain two image signals under different exposure conditions and composite them. Relevant as evidence that a single solid-state image sensor could be configured/driven in multiple readout modes, and that per-region image data was processed digitally. Source: https://patents.google.com/patent/US5420635

US 5,606,392 (Eastman Kodak), issued Feb. 25, 1997 — "Camera using calibrated aperture settings for exposure control." ⚠️ I could not retrieve the full text; on the title alone it is a camera exposure-control calibration reference in the same field and is cumulative/secondary to the grounds below. I do not rely on it as a primary reference.

2.4 References the '147 specification itself acknowledges

The Background section expressly describes, as known techniques:

• US 4,192,587 — proportional fill flash by determining subject range and varying the time at which the flash is fired relative to the exposure interval so the flash fires at an aperture corresponding to subject range → range-based flash firing timing.
• US 4,255,030 — proportional fill flash by quenching a quench strobe based on the integration of both ambient and flash → quench control of artificial illumination.
• US 4,285,584 — a photometer with three zones "for distinguishing between background, central, and foreground portions of the scene," whose segment outputs "are compared to increase or decrease the exposure depending on whether the scene is more heavily illuminated in the background or foreground" → region-wise brightness sensing and subject-vs-background comparison.
• US 4,785,322 — the "IR wink" ranging technique (also the subject of a retrieved full text): a black IR-pass filter moved in front of the strobe so a preliminary low-power "wink" is IR-only; an IR sensor and a separate visible-light sensor; a range evaluator converts reflected IR to subject distance and drives the lens. Source: https://patents.google.com/patent/[US4785322A](/patent/US4785322A)/en

Collectively, §2.2–2.4 show that every building block the '147 claims was individually known and, in most cases, already combined in the same assignee's own cameras: region-wise brightness metering, subject-vs-background comparison, active IR ranging to locate the subject, movable IR/visible spectral filters, range-based and quench-based fill-flash timing.

3. Element-by-element mapping of independent claim 1

Result: the only material differences between claim 1 and US 4,423,936 are (i) the vocabulary "image data"/"map"/"regions," and (ii) the implicit availability of a digital image sensor. Neither difference is a patentable distinction under KSR; the second is supplied outright by US 6,167,200.

4. The combinations, with articulated motivations

Ground 1 — US 4,423,936 alone (single-reference § 103; near § 102)

Rationale. A reference that teaches each step of a claim renders it obvious, and — as to most steps — anticipates it. Here US 4,423,936 teaches the region-wise brightness measurement, the active range measurement, the identification of the subject by nearest range, the comparison of subject-area brightness to non-subject-area brightness, and the control of the flash/ambient ratio in response. The "map" terminology is a labeling difference: the claim itself defines the "map" only as "values representative of a brightness map … corresponding to each of a first set of regions," which is precisely what 4,423,936's per-portion intensity signals are.

What a PHOSITA would have seen as obvious: re-expressing the analog per-photocell signals of 4,423,936 as a digital array of region values requires no inventive faculty.

Weak point: if the patentee narrows "map" to mean a CCD pixel array, Ground 1 is defeated as to that limitation, and Grounds 2–4 pick it up.

Ground 2 — US 4,423,936 in view of US 6,167,200 (primary digital-camera combination)

References: US 4,423,936 (Polaroid) + US 6,167,200 (Minolta).

What the combination supplies. US 6,167,200 supplies the modern digital capture front end that the '147 uses as its "cost-saving" advance: a single image sensor that "senses an image of a subject … and output[s] subject region information by processing data of the image," a multi-division photometric measurement of image regions (the "brightness map"), and a distance/focusing device whose output is used "to detect the subject region with a higher precision" (the "range map"), all feeding an exposure calculator. Grafted onto 4,423,936's comparison-and-classify logic and its variable-output quenchable strobe, the combination reads on claim 1 step-for-step and on claim 6's "at least one sensor assembly … operable for sensing range data from a second set of generally independent regions."

Motivation (explicit, TSM-type).

1. Same field, same problem, same solution architecture. Both references address automatic exposure control in cameras and both use region-based measurement of a subject to set exposure. KSR holds that combination of references addressing the same field and problem is likely obvious.
2. The '147 specification itself supplies the motivation. The Background states the invention's object is to avoid the cost of a "multi-sensor array" in a camera with a digital capture mode: "in a camera with a digital capture mode the use of a multi-sensor array to minimize the problem adds to the overall cost to a system." That is an express cost-driven, predictable-substitution rationale — exactly the "simpler, cheaper" rationale the Supreme Court endorsed in KSR. The '147's own stated improvement over 4,423,936 is to use the image sensor the camera already has to do the job the photocell array was doing.
3. Reasonable expectation of success. US 6,167,200 already demonstrates that a single image sensor plus a distance sensor can locate the subject region and compute exposure; 4,423,936 already demonstrates what to do with that location (compare subject vs. background brightness; set the ambient/flash ratio). The combination is a predictable aggregation of known functions with no asserted synergistic result beyond correct fill-flash exposure — which 4,423,936 already achieved.

Ground 3 — US 4,423,936 in view of US 4,304,476 (and, alternatively, US 4,785,322) for the filter/dual-condition limitations

References: US 4,423,936 + US 4,304,476 (+ optionally US 4,785,322).

What the combination supplies. This ground expressly targets claim 9 and the structural claim-6 element requiring one sensor assembly to sense both brightness and range. US 4,423,936 discloses a single array with "infrared filters selectively positioned in front thereof during ranging operations." US 4,304,476 discloses, in a camera photosensor, a carrier that moves a full IR-attenuating filter and a partial IR-attenuating filter into and out of the light path — one condition passing visible (and blocking IR), the other passing IR — automatically actuated by a flash-sensing member. US 4,785,322 discloses the same idea applied in front of the strobe (a movable black/IR-pass filter) plus separate IR and visible sensors. The '147's own FIG. 1 uses exactly this architecture: a filter element 107 moved by motor 111 between a visible-pass filter 109V and an IR-pass filter 109IR, optionally "disposed in front of the strobe 103."

Motivation. Both references are same-field (camera exposure control) and are commonly assigned to Polaroid with 4,423,936 and with the '147 itself; a PHOSITA is charged with knowledge of an assignee's own related work (and here the '147 specification admits the technique). The '147 specification even endorses the alternative: "the present invention envisions the use of differently configured image acquisition modules with a variety of techniques for presenting an IR filter over such a module, such as by moving an IR filter in front of the acquisition module by means of a stepper motor or solenoid." Choosing a single sensor with a movable spectral filter over two dedicated sensors is a predictable design choice balancing cost and part count — a classic KSR obviousness posture.

Ground 4 — US 4,285,584 / US 4,192,587 / US 4,255,030 in view of US 4,423,936 (the "Polaroid mosaic")

References: US 4,423,936 + US 4,285,584 + US 4,192,587 + (US 4,255,030, US 4,785,322).

This ground is essentially the combination that Polaroid's own engineers had already assembled, and it independently renders claims 1 and 6 obvious even if one of the references in Grounds 2–3 is challenged:

• US 4,285,584 → per-zone brightness sensing (background/central/foreground) and comparison of zone outputs to raise or lower exposure → steps (a), (b), (e).
• US 4,423,936 → subject identification by range and flash-ratio programming → steps (c), (d), (e), (f).
• US 4,192,587 → range-determined flash firing time → claim 2's firing-interval control.
• US 4,255,030 → quench-strobe fill flash from integrated ambient+flash → claim 2 and step (f).
• US 4,785,322 → IR wink ranging and movable IR-pass filter → steps (c)/(d) and claim 9.

Motivation. Combined-system-of-subsystems argument: where the references are all directed to the same problem (correctly exposing a subject against a differently-lit background) and are all commonly assigned, the artisan has both the reason and the ability to pick and combine the known solutions. The '147 specification itself narrates them as an integrated line of development.

Ground 5 — US 5,420,635 in view of US 4,423,936 (for the differing-resolution claims 3/7)

References: US 5,420,635 (Fuji) + US 4,423,936 (+ US 6,167,200).

This is the ground aimed at claims 3 and 7 ("one of the brightness or range sensing is performed in a first sensor resolution mode and the other … in a second sensor resolution mode"). US 5,420,635 discloses a solid-state electronic imaging device (two sets of photodiodes, one filtered, feeding different transfer paths) that is driven differently to produce different image-signal sets — evidence that a single solid-state imager could be operated in different readout configurations. US 6,167,200 shows the image sensor being used for region/subject processing separate from the photometric sensors. Combining: run the ranging pass at low resolution (fast, and sufficient, because IR ranging only needs region-level granularity) and the brightness/exposure pass at high resolution (needed for exposure and image quality).

Motivation. (i) A recognized design incentive to reduce readout time and processing load, as the '147 specification itself states ("the CCD is set to low resolution … so that a ranging map … can be formed"; high resolution for the brightness map) — KSR treats such an optimization as an obvious design choice where the result is predictable. (ii) The '147 specification concedes the alternative — "the image sensing CCD can be operated in only one resolution, so that the ranging and brightness information can be taken simultaneously" — showing that mode selection was a matter of ordinary design choice, not invention.

Weak point (important): This is the thinnest ground. US 5,420,635 is about different exposures and path-splitting, not about resolution-mode switching per se, and the claims' "resolution mode" limitation is the least well-met by the retrieved art. A rigorous rejection on claims 3/7 would rest primarily on design-choice/known-optimization reasoning plus the patent's own statement of the alternative, and I would want to locate additional CCD-binning/low-resolution-preview art before relying on it in a validity opinion. I state this rather than overclaim.

5. Dependent claims 2–10

Summary: claims 1, 6, 9 (and, as applications of established design practice, 2, 4, 5, 8, 10) are strongly obvious over the cited and admitted art. Claims 3 and 7 are the only ones where the retrieved prior art is materially short of a clean read, and I would not assert them as certain without additional art on per-mode sensor operation.

6. Objective indicia (secondary considerations)

I found no evidence of secondary considerations that would rebut these grounds:

• No commercial success tied to the claimed subject matter was identified; the patent is expired (anticipated expiration 2020-12-19) and its enforcement history is PAE-campaign litigation by Cedar Lane Technologies Inc.
• No nexus evidence — the accused products in the reported suits (TCL, Lenovo, Asustek, Alterna) are general-purpose consumer devices, not embodiments whose success flows from the "brightness + ranging mapping" comparison.
• No unexpected results or long-felt-but-unmet need is asserted in the specification; to the contrary, the specification frames the invention as a cost-reduction over the known multi-sensor approach.
• No validity adjudication exists — the earlier sections confirm zero PTAB proceedings and no judgment on validity, so there is no record of a tribunal crediting objective indicia. The patent issued over only two cited references (US 4,304,476 and US 6,167,200); the far closer US 4,423,936 was not cited, notwithstanding that it is the assignee's own patent and is discussed in the specification.

7. Where this analysis could be attacked (patentee's likely rebuttals)

1. "Map" means a per-pixel digital array, not three analog photocells. This narrows claim 1 past US 4,423,936 as to that term — which is why Grounds 2 and 5 (adding US 6,167,200 and US 5,420,635) matter. In my view the claim's own definition ("values representative of … a map … corresponding to each of a first set of regions") defeats a pixel-only construction, but the point is contestable.
2. Hindsight recombination. The strongest answer is that the motivation is not reconstructed: the '147 specification itself recites US 4,423,936 as the starting point and itself states the cost objection to the multi-sensor array in a digital-capture camera. That is an on-the-face, non-hindsight motivation.
3. Claims 3/7. As noted, the resolution-mode limitation is the patentee's best redoubt. It depends on how broadly "resolution mode" is construed and on whether better low-resolution-ranging art can be produced.
4. "Generally independent" region sets (claim 6). The patentee may argue that 4,423,936 uses the same three regions for ranging and metering, not "generally independent" sets. Under KSR, using the same regions for both is an obvious and indeed advantageous simplification (and the '147 specification concedes single-readout operation), so this is a weak distinction — but it is a distinction the claim's wording invites.

8. Bottom line

• Primary ground: US 4,423,936 alone — admitted prior art in the '147 specification, and in substance disclosing all six steps of claim 1 and all four processor functions of claim 6 (region-wise brightness measurement, active IR ranging to identify the nearest subject, comparison of subject-area vs. non-subject-area brightness, and flash/ambient ratio control via a quenchable strobe).
• Best full combination: US 4,423,936 + US 6,167,200, optionally further in view of US 4,304,476 and US 4,785,322 for the movable IR/visible filter assembly of claim 9 and the single-sensor dual-function architecture of claim 6.
• Motivation is supplied three ways: (i) same-field/same-problem references; (ii) an express cost-driven substitution rationale written into the '147 specification itself; and (iii) common assignment to Polaroid across the 4,192,587 / 4,255,030 / 4,285,584 / 4,423,936 / 4,785,322 family on which the '147 builds.
• Confidence: high for claims 1, 2, 4, 5, 6, 8, 9, 10; materially lower for claims 3 and 7, where the retrieved art does not cleanly reach the "different resolution modes" limitation and the case would rest on design-choice reasoning plus the specification's own concessions.
• Corrections needed in this file before reuse: the Minolta reference is US 6,167,200, not "US 6,720,000/'000-family"; and the TCL complaint (2020-06-22) was filed before, not after, the 2020-12-19 expiration.

Verify before filing: run a full-text search on US 4,423,936 and US 4,785,322 together with the '147's claims in PatentCenter/Global Dossier, and obtain the complete text of US 4,285,584, US 4,192,587, US 4,255,030 and US 5,606,392 (the last two are the references I could not fully retrieve here — my characterizations of 4,192,587, 4,255,030 and 4,285,584 come from the '147 specification's own descriptions and should be confirmed against the originals).