US 6505959

I'll search for the specific patent number as requested.

Let me verify whether there's any 2026 CAFC docket or litigation activity specific to this patent.

US Patent 6,505,959 — Verification Summary

Search scope: USPTO (patent full text via Google Patents / USPTO PTACTS), FreePatentsOnline, and a CAFC 2026 docket sweep. Result: I found authoritative bibliographic and claim data for US 6,505,959, but no Federal Circuit 2026 docket or appeal involving this patent number. The only litigation-adjacent hit is IPR2015-00506, where "US6505959 Masaki" appears as Exhibit 1036 (i.e., used as prior art against a different patent) — not as the challenged patent. So there is no 2026 CAFC activity for 6505959 that I can confirm.

Bibliographic Data (as listed literally)

Source: https://patents.google.com/patent/US6505959/en ; https://www.freepatentsonline.com/6505959.html ; https://patents.justia.com/patent/6505959

Abstract (verbatim)

"A directional diffusing film of the invention includes a base film, and a plurality of convex directionality-providing elements regularly arranged on at least one surface of the base film. A section of a first directionality-providing element in a first plane including a top of the directionality-providing element has a shape of a substantially triangle, and a section of the directionality-providing element in a second plane including the top of the directionality-providing element and perpendicular to the first plane has a top of a second directionality-providing element and a shape of a continuous wave. The directional diffusing film having characteristics specified by the invention can diffuse light in proper directionally diffused light, while maintaining high light-diffusing ability. The directional diffusing film utilizes light highly efficiently as compared with conventional diffusing films."

Independent Claims — Plain-Language Overview

The granted patent has 11 claims. Three are independent: claim 1 (the film itself), claim 10 (a surface light source unit), and claim 11 (a liquid crystal display). Claims 2–9 depend from claim 1.

Claim 1 — Directional diffusing film (the core product claim)

An optical film made of two parts:

1. a base film, and
2. a set of convex "directionality-providing elements" (small raised bumps/prisms) arranged in a regular pattern on at least one surface of the base film.

The bumps are defined by two orthogonal cross-sections taken through the top of a bump:

• Cut one way (a first plane through the peak), each bump is substantially triangular.
• Cut the perpendicular way (a second plane, also through the peak), the profile traces a continuous wave that runs from one bump's top and onward through the top of the next bump.

In short: a regularly patterned micro-prism surface combining a triangular (prism-like) profile in one direction with a wave profile in the orthogonal direction, to control and direct diffusion rather than scatter randomly.

Claim 10 — Surface light source unit

The same film, but claimed in combination as a backlight assembly: a light source + a surface light-emitting means (e.g., a light guide plate) with a light-emitting surface that projects light from the source in a predetermined direction + the claim-1 directional diffusing film. The film has the same two-cross-section geometry (triangular section in a first plane; continuous-wave section in the perpendicular second plane).

Claim 11 — Liquid crystal display

The claim-10 assembly (light source + surface light-emitting means + the same directional diffusing film) plus a transparent liquid-crystal element positioned on the light-emitting side of the film, i.e., the backlit LCD incorporating the film. Same geometry requirements.

Note on claim status: the pre-grant publication US 2001/0046134 A1 had 15 claims, including method-of-manufacture claims (drafting to a "preparing step" of a molding cylinder and a "molding step" using ionizing-radiation hardening resin and cell-engraving with a diamond stylus). The granted patent as published shows 11 claims and no independent method claim; the manufacturing disclosure is retained in the specification (FIGS. 3–4) but is not in the granted claim set as shown.

Key dependent limitations (context)

• Claim 3: the continuous wave is substantially sinusoidal.
• Claim 4: the wave has wavy parts (at the elements) with straight parts between adjacent wavy parts.
• Claim 5: the triangular section is isosceles.
• Claim 6: vertex angle 80°–100°.
• Claim 7: the apex may be rounded and/or truncated by a predetermined amount.
• Claim 8: elements arranged so incident light at 70°–80° exits at a maximum outgoing angle of 25°–40°.
• Claim 9: elements arranged so haze value is 70–90 for light entering the receiving surface.

Embodiment / Figures Highlights (for context, from the specification)

• The elements can be visualized as an isosceles-triangle section (α = 90°) swept along a sinusoidal waveform; the working example used a PET base film (100 µm, Toyobo A4300) and a UV-curing resin (RC19-793, Dai Nippon Inki Kagaku Kogyo).
• The molding cylinder cavities were cut by gravure electronic engraving with a 90° diamond stylus, 100 lines/cm, at 4°, tip truncated 5 µm.
• Measured result vs. a Tujiden D121-based comparative backlight: 1495 cd/m² (102.1%) vs. 1465 cd/m² (100%) front luminance, and no particles fell on cutting/assembly (versus resin fragments from the bead-based comparative).

Uncertainty / Caveats

1. No authoritative CAFC 2026 docket or appeal for 6,505,959 was found. The patent is recorded as expired as of 2021-04-23, which makes live 2026 appellate litigation unlikely. I found only an IPR proceeding (IPR2015-00506) in which this patent was submitted as prior-art Exhibit 1036, not challenged.
2. I could not independently confirm via the PTACTS document whether any petition/paper naming "Masaki et al." is an active 2026 proceeding; the PTACTS hit I retrieved contained the patent's own text and does not by itself establish a 2026 case.
3. Claim-set difference between the 2001 pre-grant publication (15 claims, incl. method claims) and the granted patent (11 claims as displayed) is reported as shown in the sources; I did not retrieve a certified USPTO copy to rule out a display discrepancy.
4. Legal-status entries are database "assumptions" per the source disclaimers and are not legal conclusions.

Primary authoritative source: https://patents.google.com/patent/US6505959/en

I'll research litigation involving US patent 6505959. Let me search multiple sources.

Let me search targeted litigation databases and the patent's format with commas.

Litigation search results for U.S. Patent No. 6505959

Bottom line: I found no known litigation (district court, ITC, or Federal Circuit appeal) in which U.S. Patent No. 6505959 was asserted or challenged. All searches returned either unrelated matters or references to the patent as prior art in someone else's proceeding.

What I searched

• Google Patents page for US6505959 (litigation/"cited by" data) — https://patents.google.com/patent/US6505959
• Docket Alarm court-record search (returned the IPR exhibit below)
• Unified Patents / PTAB document portals
• General web searches for "6505959", "6,505,959", "directional diffusing film lawsuit," and Dai Nippon Printing litigation

Note on search noise: the string 6505959 matches many unrelated things (e.g., WL citations like Johansen v. Nat'l Gas & Elec. LLC, No. 2:17-cv-587, 2017 WL 6505959; a Lithuanian registry notice; a Chinese logistics penalty record). These are not the patent and I have excluded them.

Closest relevant record (NOT an assertion of the '959 patent)

This means the '959 patent appears in a PTAB proceeding only as a prior-art reference against another patent. It is not a case involving infringement of the '959 patent, and I could not confirm the full party names, outcome, or docket status from the retrieved snippet. I flag this as the single verifiable trace, not as litigation over the '959 patent.

Related Dai Nippon Printing litigation (different patents — does NOT involve the '959 patent)

Dai Nippon Printing Co., Ltd. is the assignee of the '959 patent and has appeared as a defendant in patent suits, but I found no indication those suits asserted US6505959:

• Advanced Technology Incubator, Inc. v. Sharp Corporation et al., No. 5:09-cv-00135 (E.D. Tex.), filed Aug. 10, 2009 — defendants included Sharp, Dai Nippon Printing, and DNP Color Techno Kameyama; patent-in-suit not the '959 patent. https://dockets.justia.com/docket/texas/txedce/5:2009cv00135/[118750](/patent/118750)
• Cedar Lane Technologies Inc. v. Dai Nippon Printing Co., Ltd., No. 6:21-cv-00597 (W.D. Tex.), filed June 11, 2021 — patent-in-suit not the '959 patent. https://unicourt.com/case/pc-db5-cedar-lane-technologies-inc-v-dai-nippon-printing-co-ltd-[931973](/patent/931973)

I did not identify the asserted patents in these cases, so I cannot rule out overlap with certainty; they are listed only as context for the assignee.

Confidence and caveats

• High confidence that no public record of an infringement suit asserting US6505959 was surfaced. The patent is recorded as "Expired – Lifetime" (anticipated expiration 2021-04-23) per Google Patents, which makes recent assertion unlikely.
• Not absolute. My search relied on web-indexed sources; PACER and the full Unified Patents litigation caselist were not exhaustively queried, and I could not retrieve the Unified Patents case list directly (the search returned an unrelated PTAB document). Cases filed in the late 1990s–2000s may also be under-indexed online.
• Per your instruction, I have not auto-corrected any identifiers; all numbers are reported literally as they appear in the sources.

If you want a definitive answer, the reliable next steps would be a PACER docket search for "6505959" across all district courts, the ITC EDIS database, and the Docket Alarm / Unified Patents patent-level pages for patent number 6505959 directly — I was not able to complete those direct lookups here.

PTAB / AIA Trial Landscape — US 6,505,959 B2

"Directional diffusing film" · Inventors: Tadahiro Masaki, Fumihiro Arakawa · Assignee: Dai Nippon Printing Co., Ltd. · App. 09/839,691 · Filed 2001-04-23 · Granted 2003-01-14 · Priority 2000-04-27 (JP 2000-127528)

Proceedings overview

Total AIA trial proceedings on file: 0. The USPTO Open Data Portal returns no IPR, PGR, or CBM petition ever filed against US 6,505,959. The breakdown is therefore active: 0 · claims invalidated: 0 · claims sustained: 0 · settled: 0 · institution denied: 0. All 11 claims (1–11) stand untested at the PTAB and unamended — but the patent itself expired on 2021-04-23 ("Expired - Lifetime," 20 years from the 2001-04-23 filing date), so the practical defensive posture for a defendant today is not "hardened patent" or "dead claims" — it is "expired patent with no PTAB record." Any assertion against you would be limited to pre-2021-04-23 past damages under 35 U.S.C. § 286's six-year lookback, and the PTAB route (§ 311 IPR) is largely academic because there is no injunction exposure left to enjoin.

Proceedings on this patent

None. There is no IPR####-#####, PGR####-#####, or CBM####-##### naming US 6,505,959 as the challenged patent in the ODP structured data, and web search surfaced no such filing, no Final Written Decision, no institution denial, and no Federal Circuit appeal arising from this patent.

⚠️ Look-alike to avoid: IPR2015-00506 (NOT a proceeding against this patent)

One search hit creates an easy false positive, and it is worth flagging explicitly:

• IPR2015-00506 — LG Display Co., Ltd. et al. v. Delaware Display Group LLC, filed 2014-12-30, institution decision 2015-07-06. The challenged patent in that case is US 7,434,973, not US 6,505,959.
• Within that IPR, "Ex 1036 — US6505959 (Masaki)" was submitted as an exhibit — i.e., the '959 patent was used as prior art against someone else's claims, dated 2014-12-30. It was the sword, not the shield. See the exhibit listing at Docket Alarm, IPR2015-00506 and the case page at GreyB/IPVerse — IPR2015-00506.
• Takeaway: never cite IPR2015-00506 in a brief as "the IPR on the '959 patent." It isn't one, and opposing counsel will notice.

Strategic summary

Claim status. Because no AIA trial was ever instituted, no claim of US 6,505,959 has been canceled, narrowed, or held unpatentable by the PTAB. Claims 1–11 — including independent claim 1 (the base film + regularly arranged convex directionality-providing elements, triangular first-plane section, continuous-wave second-plane section), independent claim 10 (surface light source unit), and independent claim 11 (liquid crystal display) — are all UNTESTED at the Board, and all are now expired. There are no surviving-amendment claims to track because the patent owner never filed a § 316(d) motion to amend; nothing was disclaimed or substituted.

Estoppel landscape. § 315(e)(2) estoppel is a non-issue: with no petitioner, no IPR, no FWD, no party is estopped from anything. Conversely, a defendant gains nothing from a PTAB record that doesn't exist. If you are somehow facing a demand today, your invalidity theories are unconstrained by § 325(e) or § 315(e) — but that cuts both ways, since you also get no free claim construction or claim-cancellation leverage from a prior trial. Note the only prior art affirmatively on the public record against this patent family is minimal: the examiner cited exactly one reference, US 5,552,907 (Sekisui Chemical — "Light adjusting sheet having a sinusoidal surface..."), which is worth a hard look, though a § 102/§ 103 attack on an expired patent has little commercial upside.

Pattern signals. No repeat-petitioner pattern exists, no defensive aggregator (Unified Patents, RPX, etc.) ever targeted this patent, and the patent owner (DNP) never had occasion to defend claims at the Board or to appeal a loss to the Federal Circuit. The absence of IPR activity is unsurprising here: an expired, 2000-priority, component-level optical film patent rarely attracts AIA challenges, because there is no ongoing exclusionary leverage to defeat. DNP's enforcement posture on this family appears to have been licensing/portfolio rather than litigation, and the practical life of the right is over.

Recommended next steps

1. If you are a defendant: do not build any argument on "claims canceled in IPR." There is no such proceeding. Your first-line defense is expiration: the patent's term ran out on 2021-04-23 and Google Patents records the legal status as Expired - Lifetime. Confirm the maintenance-fee/expiration record on USPTO PatentCenter for US 6,505,959 before relying on it, but if accurate, there is no prospective infringement and any damages theory is confined to pre-expiration conduct — which is now also outside the six-year window of § 286 for most (if not all) of the relevant period.
2. If a demand letter cites this patent: check whether the asserted claims are claims 1–11 as issued — those are the only claims that exist, since no reissue, reexamination certificate, or PTAB amendment has altered them. Any reference to "claims canceled at the PTAB" in a demand letter would be false.
3. Milestone tracking is unnecessary. With zero pending proceedings, there is no institution deadline, no oral hearing date, and no statutory PTAB 1-year FWD deadline to monitor. Nothing is docketed.
4. Verify independently. The negative result here is sourced from the ODP "PTAB proceedings on file" block plus web search. For a belt-and-suspenders confirmation, run the patent number through PTAB E2E and the USPTO Patent Public Search reexamination tab (to rule out any ex parte reexamination, which would not appear as an AIA trial), and check CourtListener/Court of Appeals for the Federal Circuit for any appeal that might have been filed off a reexamination rather than an IPR — nothing surfaced in search, but those are the authoritative sources for a clean negative.

Bottom line: No PTAB proceedings exist on US 6,505,959. Its claims were never adjudicated by the Board, and the patent is expired — the "PTAB story" on this one is the absence of a story, plus one exhibit citation in an unrelated IPR that should not be mistaken for a challenge to this patent.

I'll verify the assignment record directly. Let me run targeted searches on the USPTO assignment databases and cross-referencing sources.

Let me try to pin down the specific reel/frame record and check for any post-issuance transfers.

Let me attempt the USPTO assignment API/legacy endpoint and check for any later transfers.

Note before starting: I hit the tool-call ceiling while trying to hit the USPTO Assignment Center's per-patent view directly (that interface is an interactive Java/JS app that does not serve a crawlable result page, and the legacy-assignment PDF index does not expose a stable per-patent URL I could resolve). So the reel/frame numbers below are not in hand — I flag that explicitly rather than inventing them. Everything else is grounded in what I did retrieve.

Inventors

Pattern check — no anomalies found, but the underlying data is thin:

• Both inventors assigned to the same entity that is the original assignee. Inventors did not retain any interest, and there is no evidence of a post-filing carve-out or joint-inventor partial assignment.
• No evidence of departure from DNP within 12 months of filing. A third-party compilation (PatentLeaderboard) lists Tadahiro Masaki with 15 patents assigned to Dai Nippon Printing, with US 6505959 among them — that is a weak but directional indicator of continued employment rather than a quick exit. It is a secondary/aggregator source, not a USPTO record, so treat it as corroborative only: https://www.patentleaderboard.com/dai-nippon-printing-co/tadahiro-masaki/[960470](/patent/960470)
• No inventor-side later filings, no conflicting assignment to a third party, and no reissue/reassignment events appear in the Google Patents legal-events ledger.

Original assignee

Dai Nippon Printing Co., Ltd. (Tokyo-to, JP) — the assignee named on the face of the issued patent and the only assignee ever recorded.

• Primary line of business: Large-scale commercial printing and a major supplier of functional/electronic materials — including the optical films, diffusion films, and light-control films used in LCD backlight units. This is not a passive holding entity; it is a diversified, publicly listed Japanese manufacturer (Tokyo Stock Exchange, ticker 7912). Its continuing public-company status is corroborated by a 2024 dividend event record: https://www.dtcc.com/-/media/Files/pdf/2024/3/21/19486-24.pdf
• Did it ship a product embodying the claims? Substantially yes, in the sense that matters here: DNP is a commercial manufacturer of optical diffusion/light-control films for LCD backlights — the exact product category of US 6505959. The patent's own working example uses DNP-group materials (UV-curable resin RC19-793 from Dai Nippon Inki Kagaku Kogyo, i.e., a DNP affiliate). I did not find a specific DNP SKU publicly designated as practicing the claims, so I state this as strong category-level evidence, not a claim-chart finding. Broad DNP assignee portfolio for context: https://companyprofiles.justatic.com/assignee/dai-nippon-printing-co-ltd
• Current status: Operating, publicly traded, not in bankruptcy. No Chapter 7/11, dissolution, or M&A event affecting this patent was found.
• Ownership today: DNP remains the owner. The Google Patents legal-status field reads "Expired – Lifetime" with anticipated expiration 2021-04-23 — i.e., the patent ran to full statutory term with maintenance fees paid. That is itself evidence of continued DNP ownership through 2021: a patent that had been dumped to a licensing shell typically lapses for non-payment instead of expiring "lifetime." Source: https://patents.google.com/patent/US6505959/en

Assignment timeline

The record contains exactly one recorded assignment. The Google Patents legal-events ledger shows a single post-filing reassignment entry, dated 2001-05-24, from the inventors to Dai Nippon Printing Co., Ltd., described as "ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS)," with assignors listed as ARAKAWA, FUMIHIRO and MASAKI, TADAHIRO. There is no subsequent security agreement, merger, change of name, license recordation, release, correction, or transfer of any kind in the sources I could reach.

• Executed date not shown / recorded 2001-05-24 — Reel not retrieved / Frame not retrieved (see caveat below)
  • Conveyance: Assignment (inventor → corporate assignee)
  • Assignor: Tadahiro Masaki and Fumihiro Arakawa (joint inventors)
  • Assignee: Dai Nippon Printing Co., Ltd., Tokyo-to, Japan
  • Correspondent of record: Not retrieved. I could not resolve the recording attorney/agent from the sources reachable here. This is the one field you specifically asked me to capture, and I am not going to guess it. It is also the field with the least diagnostic value here, because there is only one link in the chain — a "repeat correspondent" signal requires at least two links, and this chain has one.
  • Context: Standard employment/inventor assignment at filing — not a fire-sale, not a securitization, not a transfer-to-asserter, not a change of name. This is the ordinary "we own our employees' inventions" recordation.

Caveat on reel/frame: The USPTO Assignment Center (https://assignmentcenter.uspto.gov/, mirror at https://assignment.uspto.gov/patent/index.html) is the authoritative source for reel/frame and correspondent, and its per-patent lookup is interactive. I was unable to complete that direct lookup within this session. I have no reel/frame value in evidence, and I am reporting it as unknown rather than supplying a plausible-looking number. To finish this section you (or I, on a follow-up run with more steps) need one manual Assignment Center query for patent 6505959 and one for application 09/839,691.

Timeline diagram

timeline
    title Ownership of US 6505959
    2000 : JP priority filed by Masaki and Arakawa
    2001 : US application 09 839 691 filed
         : Assignment recorded to Dai Nippon Printing
    2003 : US 6505959 granted to Dai Nippon Printing
    2021 : Patent expires at full term

NPE / troll-pattern signals

Non-signal worth naming explicitly: US 6505959 appears in IPR2015-00506 as Exhibit 1036, "Ex 1036 US6505959 Masaki" — i.e., it was submitted as prior art against U.S. Patent No. 7,434,973, which was the patent actually under challenge. That is the opposite of an NPE signal: it means the '959 patent was used as a defensive/anticipatory reference by a petitioner. Source: https://www.docketalarm.com/search/?q=patent%3A%287434973%29&page=8

Verdict

Insufficient data — specifically, the "only the original assignment" branch of that category.

Justification (2–3 sentences): The Assignment Center record, as reflected in the Google Patents legal-events ledger, contains exactly one recorded assignment — the 2001-05-24 inventor-to-Dai Nippon Printing conveyance of the 2001-04-23-filed application 09/839,691 — and nothing after it, so the formal-prong test in your rubric lands on "only the original assignment." Under your own constraint that "could be a shell" is not a finding, there is no evidence-supported NPE signal at all here: no LLC transferee, no known asserter, no cascading transfers, no bankruptcy sale, no privateering, and no defensive-aggregator terminus. The affirmative evidence points the other way — DNP is an operating manufacturer of LCD optical films that held the patent to full-term expiry on 2021-04-23, and the only third-party use of the patent on record (IPR2015-00506 Ex. 1036) was as prior art against someone else's patent.

One honest qualification on the verdict label: "Insufficient data" here denotes a thin record, not an absence of evidence about the owner. If your taxonomy permits, the substantively accurate description is "operating-company-owned, non-asserting, no NPE involvement" — I chose the rubric's literal category because the chain has a single link and there is no litigation to support the "assertion" prong of the operating-company option.

Verification links:

• USPTO Assignment Center (search patent 6505959): https://assignmentcenter.uspto.gov/
• USPTO Assignment Search mirror: https://assignment.uspto.gov/patent/index.html
• Google Patents legal events: https://patents.google.com/patent/US6505959/en

Open item for a follow-up run: one manual Assignment Center query for patent 6505959 / application 09/839,691 to capture the reel/frame and the recording correspondent. Those are the only two fields in your spec I could not fill, and the correspondent field is the one that would let us check the (likely absent) repeat-attorney tell against other Dai Nippon Printing recordings.

I'll research the prior-art citations for US 6,505,959, starting with the single examiner-cited reference and then validating against the patent's own prosecution/citation record.

I have the authoritative record. Let me confirm whether the '959 patent's face lists any additional (e.g., foreign) references beyond the single U.S. citation, so my prior-art inventory is complete.

Prior-Art Analysis — U.S. Patent No. 6,505,959

Patent analyzed: US 6,505,959 B2, "Directional diffusing film" (Masaki et al.; Dai Nippon Printing Co., Ltd.)
Source of record: https://patents.google.com/patent/US6505959/en (authoritative full text supplied in the brief)
Rule applied: Identifiers are read literally. No patent number has been auto-corrected.

1. Scope of the citation record (verified, literal)

US 6,505,959 has an unusually thin citation record: the patent's own bibliography lists exactly one patent document cited by the examiner against it.

I confirmed via the USPTO/Google Patents record and cross-databases that no other patent document is cited against the '959 patent. Note a frequent source of confusion: the long "Cited By"/"Citations (51)" and "(99)" lists on the '959 page are documents that cite '959 later, or that belong to the Sekisui family — those are not prior art against '959 and I do not treat them as citations. Likewise, the IPR2015-00506 exhibit "US6505959 Masaki" (Ex. 1036) is '959 being used as prior art against another patent (US 7,434,973), not a reference cited against '959.

Therefore, the complete prior-art citation set to analyze is a single reference: US 5,552,907.

2. The one cited reference — full citation and analysis

Reference A — U.S. Patent No. 5,552,907

Brief description. Yokota discloses a light adjusting sheet for an edge-light planar lighting device in which one surface carries a plurality of convex and concave streaks arranged alternately and approximately parallel to one another, the streaks having a cross-section of a sine curve Y = a·sin(bX) (with a = 15–1500 µm; b = 0.005–1 degree/µm). The opposite surface is a "non-optically flat surface," which may be (i) a fine uneven surface (mat / sand-blast / press), (ii) a surface with a triangular cross-section (claims 5, 11; FIGS. 21/24-25), or (iii) a "moderate wave-form surface" (claims 6, 12). The sheet may also contain a light-diffusing material (claim 13). Yokota further discloses a planar lighting device (light-guide plate with a dot pattern on its back, a linear light source at a side, a reflector behind the guide, and the light-adjusting sheet in front — claims 14–15) and a liquid crystal display (same assembly with a liquid crystal element forward of the light-guide plate — claims 16–17). Peak/bottom lines of the streaks are set at a "predetermined angle" to the lamp axis. Performance data (Table 2/3) shows forward luminance and half-luminance angle ranges.

Prior-art status (dates). US 5,552,907 granted 1996-09-03. The '959 application was filed 2001-04-23 with a JP priority of 2000-04-27; both dates are more than one year after the Yokota issuance/publication. Under pre-AIA 35 U.S.C. § 102 (the governing statute here, since the application predates the AIA first-inventor-to-file changeover), Yokota is available under § 102(b) (printed publication/patent more than one year before filing) and also § 102(a)/(e). There is no date-availability dispute — Yokota is unquestionably prior art.

§ 102 anticipation mapping — claim by claim

The decisive structural question: does Yokota disclose a directionality-providing element whose cross-section in the plane perpendicular to the sine-wave direction is substantially triangular? Yokota's arcs are rounded (convex/concave arcs), and its ridges are effectively linear (lenticular) — the section perpendicular to the arc direction is essentially straight. Its triangular feature exists only as a separate pattern on the opposite face, not as the section of the same element.

Bottom line on § 102: US 5,552,907 is the only reference cited against '959, and it fails to anticipate any of claims 1–11, because in every independent claim the required substantially triangular section in the first plane (taken through the top of the element) is absent. Yokota's surface is a one-dimensionally varying sine surface (rounded arcs, straight orthogonal profile); the '959 invention is a three-dimensional element — an isosceles-triangle section swept along a sinusoid, so that both the triangular section and the wave section occur in the same element. That three-dimensional combination is what distinguishes '959 over Yokota. (Consistent with the earlier summary, '959 issued over this reference; the granted set also drops the method claims that appeared in the 2001 pre-grant publication.)

3. Supplementary references that are germane but not citations against '959

These are offered for completeness; none is a "patent citation for 6505959." I list them so the prior-art landscape is not mistaken for the citation record.

1. US 5,394,255 A (Yokota et al., Sekisui Chemical; granted Feb 28, 1995) — the parent of US 5,552,907 (same family, same sine-curve light-adjusting sheet concept). Same § 102 defects as the '907 reference: no triangular-section-plus-wave element. Not cited on the '959 face.
2. US 5,764,315 A (Sekisui Chemical; published June 9, 1998) — a sibling in the Sekisui family (continuation/divisional lineage). Same subject matter; not cited on the '959 face.
3. US 6,002,464 (light-diffusing sheet with a "section resembling sinusoidal wave, cycloidal wave, triangular wave, trapezoidal wave" corrugated surface) and US 5,591,521 (Arakawa — appears in a different application's search report, not '959's) surfaced in searching but are not listed in the '959 citation record and post-date/relate differently; included only as background.

I flag explicitly: because the examiner cited a single reference and the claim was allowed, any obviousness theory over Yokota would have required combination with a second teaching supplying the triangular-section element — and no such second reference appears in the '959 citation record.

4. Caveats

• Single-reference record confirmed against the authoritative text (Google Patents "Patent Citations (1)" = US 5,552,907). I did not retrieve a certified USPTO "References Cited" image of the '959 front page; if the certified copy shows additional foreign (e.g., JP) documents, my inventory would be incomplete. Based on all sources retrieved, US 5,552,907 is the sole citation.
• The "Cited By" lists (US 2002/0163726 to Dai Nippon Printing's light-diffusive protective film, the 3M and Rambus documents, etc.) are later documents and are not prior art against '959.
• The § 102 conclusions are structural/anticipation conclusions based on the published claim texts of both patents; they are not a legal opinion, and claim construction of "substantially triangular" could shift the margin, though the triangular-vs-arc distinction here is stark.

Primary sources: https://patents.google.com/patent/US6505959/en ; https://www.freepatentsonline.com/5552907.html ; http://www.everypatent.com/comp/pat5552907.html ; https://patents.justia.com/patent/5552907

I'll ground this analysis in the prior-art record actually shown on the patent's page. Let me verify the one examiner-cited reference and check whether the other page-listed references qualify temporally.

The examiner-cited reference is now well-characterized. Let me verify the secondary references that appear in this patent's own family pages, so any §103 combination rests on references actually on the record.

Let me confirm the dates and assignees of the two secondary references I intend to rely on, so the §102/§103 qualification is grounded rather than assumed.

Obviousness Analysis — U.S. Patent No. 6,505,959 B2 under 35 U.S.C. § 103

0. Framing, law, and the scope of the prior-art record

Applicable law. The application was filed 2001‑04‑23 with a JP priority of 2000‑04‑27, so pre‑AIA § 103 governs. Pre‑AIA art qualifies under § 102(a)/(b)/(e). Critically, the KSR standard (flexible, "expansive and flexible approach"; a combination can be obvious where it is "the product of ordinary creativity, not of a genius") applies to pre‑AIA § 103 as construed. Graham factors govern secondary considerations.

What is actually in the page's Prior Art section. As flagged in the earlier-generated sections, the examiner cited exactly one reference: US 5,552,907 (Sekisui Chemical; Yokota et al.; issued 1996‑09‑03) — squarely § 102(b) art. Everything else on the page's "Cited By" list is later material and therefore generally not prior art (a document that cites the '959 post‑dates it). I therefore build the analysis in tiers, and I flag which tier each reference comes from:

PHOSITA. A person of ordinary skill in the art circa April 2000: a B.S. in physics/optics or materials engineering plus 2–4 years' experience designing LCD backlight optics (light guides, prism sheets, diffusers), or a technician with substantially more experience in the same work. That level of skill includes fluency with Snell's law, TIR, prism apex-angle selection, and the standard micro-replication toolkit (extrusion/embossing, UV-casting against a machined roll).

The one thing everyone agrees on: the environment is admitted prior art. The '959's own FIG. 8 (an edge-lit guide 122 with dot pattern 123, reflector 124, plural diffusing films, LCD unit 133) is expressly described as "a sectional view of a liquid crystal display … as an example of a conventional surface light source unit employing a conventional light diffusing film." And the specification admits the two-layer "base film + coated resin layer" architecture ("formed by coating a transparent resin base with an ink containing a dispersing matter"). Claims 10 and 11 therefore add no environment that was not already conventional.

1. Claim 1 vs. US 5,552,907 — element mapping and the single real gap

The gap is real but narrow. In the '959 the same element must be triangular in one plane and part of a continuous wave in the orthogonal plane; '907's corrugation is sinusoidal across the ridges and constant along them. Note, however, that '907 itself contains every building block plus express combination teaching:

• A 90° isosceles-triangle ridge array. '907 sheet (g): "a plurality of parallel streaks 91 with a lateral cross section of a right angled isosceles triangle … (the peak angle is a right angle)." That is exactly the '959's FIG. 2B geometry and its α = 90° worked example, including the "zig-zag trace" the '959 describes as the sweep shape.
• The very apex-angle range of dependent claim 6. '907 Table 1 tabulates working sheets with peak angles of 90°, 80°, 100° and 75°, and the spec says α is "in the range of 30° to 150°, and preferably of about 60° to 120°." Claim 6's 80°–100° is literally the endpoints of two of '907's own embodiments.
• Triangular and wavy profiles combined on one sheet, same pitch. '907 Embodiment 6: front surface "forming a sine curved surface," back surface unevenness "the same pitch of 400 µm as that of the front surface, but the amplitude is 20 µm"; Embodiment 7: "unevenness with a triangular cross section is provided on the back surface opposite … the front surface provided with … a sine curved surface." And claim 5 of '907: the non-optically-flat surface "has a triangular cross-section."
• An express statement that the combination is beneficial. '907: "even better results can be obtained by making the period of the uneven streaks on the back surface … the same as the period of the convex and concave streaks of the front surface and making the amplitude less than a half of that of the front surface," plus "the directionality of the light decreases if the back surface of the sheet is provided with convex and concave streaks of a cross section of a continuous curve … or of a triangular cross section."

So '907 alone comes very close; what it lacks is the single-element orthogonal dual profile. Two secondary references close it.

2. Grounds of rejection

Ground A — § 103: '907 in view of US 4,906,070 (Cobb / 3M)

Cobb discloses a "thin, flexible film … having a structured surface on one side and a smooth surface opposite…, said structured surface includ[ing] a linear array of miniature isosceles prisms …, the perpendicular sides of said prisms mak[ing] an angle of approximately 45° with said smooth surface" — i.e., a 90° isosceles prism array on a film base. Cobb's FIG. 8 and text further disclose that "peaks 17, which are normally razor sharp … may be blunted or rounded … by varying the radius r of the peaks, light leakage can be controlled."

• Claim 1: '907 supplies "base film + array of convex elements + continuous-wave section + regular arrangement"; Cobb supplies the "substantially triangular section in a first plane." The claimed swept element (triangle in the first plane, wave in the second) is the mechanical intersection of the two disclosed corrugations.
• Claims 5, 6: Cobb's prisms are isosceles with a 90° included apex — inside 80°–100°. '907's Table 1 independently discloses 80° and 100°.
• Claim 7: Cobb's rounded/blunted peaks, disclosed for the purpose of controlled light leakage, map directly onto "vertex which is rounded and/or a predetermined amount of which is cut off."
• Motivation (KSR): (i) Same field, same problem, same solution mechanism — both are light-transmitting films with a ridged structured surface placed over an edge-lit guide to redirect light that "usually goes out from the light guiding plate at a very small angle from the surface" ('907 spec). Cobb's prisms refract/TIR oblique rays toward the normal; '907's sine ridges concentrate light "into the forward direction." (ii) '907 itself supplies the motivation to put a triangular profile into the same sheet as a sine profile (its Embodiments 6–7 and claim 5). (iii) Predictable result: apex angle and pitch are recognized result-effective variables; the '959's own comparative data shows only a ~2% front-luminance gain (1495 vs. 1465 cd/m²) over a bead-diffuser stack — the antithesis of an unexpected result.

Ground B — § 103: '907 in view of AU Optronics US RE41,566 E (and its original)

The AUO disclosure is even closer textually: "an optical film of transparent material comprises a first surface having a wave structure including a plurality of isosceles triangle prisms arranged side-by-side, and a second surface having an optically rough structure for performing diffuse transmission," with a top angle of 95°–120°, positioned "between the back surface of the LCD panel and the top surface of the light guide means" with a reflector and side-mounted light source — i.e., the identical claimed environment.

• Claims 1, 5, 6, 11: supplies the isosceles-triangle element in a wave-structured surface within an edge-lit LCD; 95–100° overlaps the claimed 80–100°.
• Claim 9 (haze 70–90): the "optically rough structure for performing diffuse transmission" is a diffusion/haze-generating function, and '907 claim 13 teaches the sheet "contains a light diffusing material." Haze in 70–90 is a routine optimization target, expressly characterized in the '959 as merely increasing "luminous intensity (density) of diffused light in a necessary range."
• Caveat: because the RE41,566 header's filing date could not be confirmed, a real rejection would need a certified copy of the original patent to fix its §102 date. If the original's filing/publication does not predate 2000‑04‑27, this ground drops out and Ground A carries the day.

Ground C — § 103: '907 in view of US 5,890,791 (Saito, Konica)

Konica claims a light-control sheet with prisms whose "two side surfaces have asymmetrical shapes … and at least one of the two side surfaces is nonplanar." This is the obviousness route to claims 1 and 7 where the element faces are curved rather than planar — the '959 expressly contemplates that "the outline 12a of the section DD … may have straight lines dependently on a method and/or condition for forming a molding cylinder," i.e., the curvature/straightness of the profile is presented as a process artifact, not a point of novelty.

Ground D — § 103: '907 (claims 14 and 16) in view of the '959's admitted prior art → claims 10 and 11

This ground needs no prism reference at all for the assembly limitations. '907 claim 14 recites a "planar lighting device comprising: a light guiding plate having a dot pattern on a back surface; a linear light source placed on at least one side of said light guiding plate; a reflector plate placed in back of said light guiding plate; and a light adjusting sheet placed at the front of a light emitting surface of said light guiding plate … peak lines of said convex regions … arranged to make a predetermined angle with an axis of said linear light source." '907 claim 16/17 adds "a liquid crystal display element being forward of said light guiding plate."

That is the whole environment of the '959's claims 10 and 11 — light source + surface light-emitting means + film (+ LC element on the light-emitting side). US 5,394,255 / US 5,764,315 (Tier B, same inventors) supply the multi-film stacking limitation ("peak lines … of one single sheet [make] an angle of 5° or greater with … at least one other single sheet"), which maps onto the '959's disclosed 4°/45° and 45°/45° two-film orientations. Again, the only surviving difference is the film geometry of claim 1.

Ground E — claims 2, 3, 4, 8, 9 as independent obviousness findings

3. Secondary considerations (Graham) — thematically absent

• Unexpected results: the patentee's own Table 1 shows 1495 vs. 1465 cd/m² (+2.1%) against a three-film Tujiden D121 stack — modest and directionally expected from adding a prismatic collimator to a diffuser. Luminous-intensity data (FIGS. 7A/7B) shows improvement over a conventional bead stack, not over the closest art.
• Long-felt need: '907 was already expressly motivated by the same need — "the light in the forward direction is scarce, so that the luminance … is low," and the need for thinness ("the back light is required to be thin"). No unmet need survives.
• Teaching away: none. '907 does not disparage triangular or prismatic profiles; it claims one (claim 5) and builds one (sheet (g)).
• Copying / commercial success / nexus: nothing in the record establishes a nexus; the "particle falling" advantage (no beads → no dust on cutting) is a use of the admitted bead-free architecture, not a nexus to the claimed dual profile.
• Note the "2% and no dust" framing: the specification's own objective is a drop-in replacement for bead diffusers at a comparable cost — the hallmark of an obvious substitution, not a new principle.

4. Weakest links and what to verify before relying on this

1. Claim 1's orthogonal-section geometry is the entire case. If the final claim construction requires the second plane to show a wave connecting successive element tops (a serrated ridge line, not a furrowed corrugation), Grounds A–C are combinations, not anticipations, and the Federal Circuit's "predictable result" law controls. Expect a counter-argument that '907's corrugation and Cobb's prisms "differ in principle" (Cobb is a TIR/light-transport film; '907 is a refracting diffuser). This is a non-analogous-art / different-principle attack; it is beatable because both references are addressed to LCD backlight luminance and both are expressly cited in the same substrate—but it is the strongest defense argument.
2. Do not use US 5,995,288 as a § 103 reference. It is DNP-assigned with a shared inventor (Arakawa) and would be disqualified under pre‑AIA § 103(c) if commonly owned at the time of invention. Similarly, the examiner's citation of a single reference means the file history likely contains applicant arguments distinguishing '907 on the dual profile — retrieve the '959's file wrapper before filing anything, since those arguments may supply prosecution-history-estoppel or narrowing constructions that change the analysis.
3. Verify § 102 dates from certified copies for RE41,566's original, US 5,890,791, and US 4,906,070; only '907 (Tier A) and the Sekisui family (Tier B) have dates I can state with confidence from the page/record.
4. No AIA-trial or litigation record exists on this patent (consistent with the earlier-generated PTAB and litigation sections), and the patent expired 2021‑04‑23. Obviousness here is therefore a hypothetical/defensive exercise; there is no live injunction exposure and damages are confined to pre‑2021 conduct outside § 286's six-year lookback for most periods.

5. Bottom line

Claims 2, 3, 4 are directly disclosed by '907 (a periodic sinusoidal ridge array, with flat connecting surfaces). Claims 10 and 11 are obvious from '907 claims 14/16/17 plus the applicant's own admitted FIG. 8 backlight/LCD environment, with multi-film angular stacking coming from the same Sekisui family. Claim 1's triangular-section element, and hence claims 5, 6, 7, are obvious over '907 in view of US 4,906,070 (90° isosceles prisms on a film; rounded peaks for controlled leakage) or, alternatively, AU Optronics RE41,566 (isosceles-triangle prisms in a "wave structure" on an edge-lit LCD film — subject to date verification). Claims 8 and 9 are obvious as predictable, result-effective-parameter outputs of that geometry, unsupported by any criticality showing. The single strongest obstacle to a clean § 103 case is the "one element, two orthogonal profiles" limitation, and the primary motivation to bridge it comes, notably, from the primary reference itself — '907's express teaching that same-pitch triangular and sine profiles on one sheet give "even better results."