Invalidity dossier
US 5775791
Surface emission apparatus
Current assignee: Nidec Precision Corp
Added 9/23/2026, 9:17:29 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 5,775,791 A
Title: Surface emission apparatus
Assignee/Current Assignee (per source): Nidec Precision Corp; original assignee Nidec Copal Corp
Inventors: Yukio Yoshikawa; Shigekazu Nakamura
Prior art date / Priority date: 1992-08-31 (priority claimed from PCT/JP1993/001238)
Filing date: 1993-09-01
Publication (grant) date: 1998-07-07
Application number: US08/338,580
Status: Expired – Lifetime (anticipated expiration 2015-07-07)
Source: https://patents.google.com/patent/US5775791/en
Purpose: The patent addresses backlighting for a liquid crystal display panel or similar illuminated body. As panels grew larger and devices demanded low-profile, compact, lightweight construction, conventional light-guide plates produced uneven brightness—brighter near the light source, darker farther away. The stated object is to provide a surface emission apparatus that uniformly emits light across the entire light-emitting surface.
Plain-language scope: Light from a source (4) enters an end face (1f) of a transparent light-guide plate (1). Small projecting portions (31) are formed integrally on the bottom surface (1b) opposite the light-emitting surface, acting as reflecting shape portions. Their sections parallel to the bottom surface are circular, and the parts extending from each vertex to the bottom surface form curved surfaces of radius R (edge portions); alternatively the projecting portions may be circular cones with a vertex angle of 90°–140°. Light striking these edge portions reflects and emerges from the upper surface (1a), then passes through a diffusion plate (2) and exits the light-emitting surface (2a). Critically, the density of the projecting portions increases with distance from the light source, and they are arranged in a staggered manner away from the light source, making emitted light easy to couple directly into many projecting portions and controlling reflectance to even out brightness. Example dimensions: height h ≈ 0.03–0.07 mm; diameter d ≈ 0.05–0.2 mm; plate thickness H ≈ 1 mm. Two light sources at both ends, with highest density at the center, is also described. The plate can be made at low cost since projecting portions are integrally formed without post-processing such as hairline formation.
What the excerpt does not establish: It does not provide the full claims (only definitions/description and figures), all embodiments, exact numerical limits beyond those quoted, or any legal conclusions on validity, enforceability, or ownership transfers. The status shown is expressly an assumption, not a legal conclusion.
Generated 10/1/2026, 9:34:25 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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