Invalidity dossier
US 4043636
Illumination-panel for liquid crystal display of similar device
Current assignee: Intel Corp
Added 9/23/2026, 1:21:32 PM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 4,043,636 A
Title: "Illumination-panel for liquid crystal display of similar device" (title as given in the source).
Patent number / application: US 4,043,636 A; application US 05/600,979.
Inventors: Noel H. Eberhardt and Ron F. Keller.
Assignee: Intel Corp (listed as original assignee and current assignee).
Key dates (as listed): Prior art date 1974-12-23; filing date 1975-08-01; publication/grant 1977-08-23; anticipated expiration 1994-08-23. Legal status listed as "Expired – Lifetime."
Purpose (from the text): The invention "relates to the field of brightness enhancement for liquid crystal displays for watches and similar devices." The background explains that liquid-crystal displays operate by a liquid crystalline substance changing to an "excited" state above a threshold voltage, producing a greater optical coefficient of scattering than "unexcited" portions—used to form alphanumeric displays such as digital watch displays ("dynamic scattered liquid crystals displays").
Plain-language scope: The text describes illumination modes for such displays. Two basic groups are identified: a transmissive mode (liquid crystalline layer between light source and observer) and a reflective mode (observer and light source on the same side). In the reflective mode, a reflective coating is placed opposite the observer; incident light passes through the display and liquid crystal, reflects back, and selectively excited portions scatter light toward the observer, producing a brightened image on a dark background. A fraction of incident light is back-scattered to the observer; the text cites a prior report of about 10% scattering efficiency (referencing U.S. Pat. No. 3,499,112). In the transmission mode, a polarizing layer placed between source and liquid crystal, with a second polarizing layer between observer and liquid crystal, allows a uniformly dark illuminated field, with excited portions rotating polarization (text is truncated here). The excerpt also states the invention "may also be applied to liquid crystal displays employing different principles (e.g., field effect) and passive (non-radiating) displays (e.g., electrochromic)."
Source: https://patents.google.com/patent/US4043636/en
What the excerpt does not establish: The full claims, dependent-claim structure, complete specification, drawings, and any specific embodiment details beyond those quoted. It does not establish prosecution history, enforceability, or the accuracy of the listed assignee/status.
Generated 10/1/2026, 9:53:10 PM
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Litigation summary
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PTAB challenges
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Assignment history
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Prior art
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Obviousness
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Extensions
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Derivative works
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