Invalidity dossier
US 5706134
Light-diffusing sheet member
Current assignee: Keiwa KK
Added 9/23/2026, 10:05:48 PM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
US 5,706,134 — "Light-diffusing sheet member"
Bibliographic data (from supplied text)
- Patent number: US 5,706,134 A
- Application number: US 08/658,314; filed 1996-06-05
- Granted/published: 1998-01-06
- Inventors: Teruaki Konno; Koichi Sawada; Masahiro Kitamura
- Original assignee: Keiwa Shoko KK; current assignee listed as Keiwa KK (name change recorded 1999-07-08)
- Status listed: Expired – Lifetime; anticipated expiration 2012-09-30
- The listing shows a "prior art date" of 1919-06-22 and labels priority dates as assumptions, not legal conclusions.
Purpose
The patent concerns a light-diffusing sheet member that uniformly diffuses light, particularly for use as a light-diffusing plate that uniformly diffuses light transmitted from a light source serving as the backlight of a liquid crystal panel in a liquid crystal display.
Plain-language scope
The supplied text describes a diffusing plate 13 positioned above a guide plate 12, which guides upward light from a fluorescent tube 11 backlight; diffused light passes to a liquid crystal display unit 14 above. The diffusing plate may be a light-diffusing sheet member in which a resin such as polycarbonate is melted and extruded onto a base material surface and finished with a pressing/cooling "mat roll" having many fine concave and convex portions, or the resin is heated and pressurized by a pressing roll having many fine convex portions so the resin is embossed with fine concave and convex portions. The excerpt also notes Japanese Utility Model Publication No. 26481/1991 disclosing a light-diffusing sheet member in which a light-diffusing layer containing light diffusing materials is affixed to a polyester film surface; that passage is truncated in the supplied text.
Source: https://patents.google.com/patent/US5706134/en
What the excerpt does not establish
The excerpt omits the claims, abstract, examples, and most of the description; it does not establish the full claimed scope, claim limitations, measured optical properties, all cited prior art, or the accuracy of the listed dates and assignees.
Generated 10/1/2026, 9:33:46 PM
Cases on file (0)
Specific litigation cases in our database that name US patent 5706134. The free-form analysis below may also discuss cases beyond this list.
No cases on file mention this patent. Upload a CSV or add a case manually in Admin → Manage litigation cases.
Litigation summary
Past and pending lawsuits — plaintiffs, defendants, jurisdictions, outcomes, and notable rulings.
Proceedings on file (0)
All PTAB activity →AIA trial proceedings (IPR / PGR / CBM) filed at the USPTO Patent Trial and Appeal Board against this patent. Sourced from the USPTO Open Data Portal and refreshed every six hours; each proceeding number deep-links to the PTAB E2E docket.
No PTAB proceedings on file. This patent has not been challenged via IPR, PGR, or CBM. The absence is itself a signal — well-asserted patents eventually attract IPRs. The LLM analysis below may surface filings the ODP feed hasn’t indexed yet.
PTAB challenges
AIA trial proceedings at the USPTO Patent Trial and Appeal Board — IPR, PGR, and CBM. Petitioners, judge panels, claim-level invalidation outcomes from Final Written Decisions, and Federal Circuit appeals. The single most important defensive datapoint after litigation history.
Assignment history
Inventors, original assignee, and the chain of ownership recorded with the USPTO — including the correspondent attorney who recorded each assignment, since shell-LLC chains often share one repeat-player attorney even when the entity names look unrelated. Surfaces NPE / patent-troll patterns: shell-entity transfers, known asserters in the chain, repeat correspondent fingerprints, pre-litigation assignments, and bankruptcy fire-sales.
Prior art
Earlier patents, publications, and products that may anticipate or render the claims unpatentable.
Obviousness
Combinations of prior art that suggest the claimed invention would have been obvious under 35 U.S.C. § 103.
Extensions
Patent term adjustments, term extensions, continuations, divisionals, family members, and expiration dates.
Derivative works
Defensive disclosure: derivative variations of each claim designed to render future incremental improvements obvious or non-novel.