Invalidity dossier
US 5377084
Surface illuminating apparatus
Current assignee: T Chatani and Co Ltd
Added 9/23/2026, 7:25:29 PM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 5,377,084 A
Title: Surface illuminating apparatus
Patent number: US 5,377,084 A
Application number: US 08/130,187
Inventors: Takeshi Kojima; Shinpei Ninomiya
Assignee: T. Chatani and Co., Ltd. (original assignee; assignment recorded 1993-10-01)
Priority date: 1992-10-08
Filing date: 1993-10-01
Grant/publication date: 1994-12-27
Anticipated expiration: 2013-10-01; status listed as "Expired - Lifetime"
Source: https://patents.google.com/patent/US5377084/en
Purpose: The invention relates to a surface illuminating apparatus used mainly as a back light for a liquid crystal display. The stated problem is that conventional apparatus cannot obtain sufficiently high brightness while keeping a uniform ratio of illuminance across the entire liquid crystal display panel, so the display is hard to recognize uniformly within an angle of visibility (generally 60°). The invention therefore alters the light diffusion plate.
Plain-language scope (per the excerpt): The apparatus includes a transparent plate; a reflecting plate layered on its rear surface; an irregular reflecting layer between them; a light diffusion plate layered on the front surface of the transparent plate; and light sources at both lateral ends of the transparent plate. A plurality of spotted projections having light condensing and diffusion functions are formed on the outer side surface of the light diffusion plate. The projections are preferably hemispherical and arranged in a zigzag pattern. Light passing through the transparent plate is condensed by the lens effect of each projection and diffused, raising brightness within the angle of visibility while maintaining a uniform illuminance ratio. The zigzag arrangement is said to make intervals nearly uniform and minimal, increasing projection density.
What the excerpt does not establish: It does not reproduce the full claims, the complete description, the drawing contents (FIGS. 1–8), or the second embodiment details (truncated at FIG. 5). It does not establish claim scope, validity, enforceability, or the content of any prior-art reference beyond the mention of Japanese Utility Model Laid-Open Gazette No. Sho 58-38186. Litigation and ownership-transfer details were not examined.
Generated 10/1/2026, 9:42:06 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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