Invalidity dossier
US 5598281
Backlight assembly for improved illumination employing tapered optical elements
Current assignee: Honeywell International Inc
Added 9/23/2026, 10:21:00 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 — US5598281A
Title: Backlight assembly for improved illumination employing tapered optical elements
Patent number: US5598281A
Application number: US08/203,232
Inventors: Scott M. Zimmerman; Karl W. Beeson; Paul M. Ferm
Original assignee: AlliedSignal Inc. (current assignee listed as Honeywell International Inc.)
Priority/filing date: 1993-11-19
Publication (grant) date: 1997-01-28
Legal status: Expired – Lifetime (anticipated expiration 2014-01-28)
Purpose. The patent addresses direct-view electro-optical displays, such as liquid crystal displays (LCDs), and more particularly backlit displays for military and avionics applications. The stated aim is to provide an efficient, bright, uniform image with high contrast, viewable over a wide viewing angle, in a low-profile assembly. The text notes that transmissive LCDs require a backlight, that LCDs suffer low contrast and chromaticity shifts at large viewing angles, and that the backlighting scheme is important to both image quality and display profile. The patent characterizes itself as directed to flat panel displays having an improved backlit electronic display.
Plain-language scope. According to the title, the assembly is a backlight for improved illumination that employs tapered optical elements to distribute light from a source across the display. The supplied text also references prior arrangements via EPO 0 525 55 A1; U.S. Pat. Nos. 4,659,185, 5,132,830, 5,159,478, 5,128,783 and 5,161,041; and Japanese Publication Nos. 245106 and 42241, and notes that the present invention is distinguished from such past backlighting configurations. The excerpt lists prior-art keywords "light," "array," "collimating," "backlight assembly," and "input surface," which suggest a collimating, array-based light-input arrangement, but the excerpt does not describe the claimed structure.
What the excerpt does not establish. It does not supply the claims, detailed description, drawing descriptions, or any express claim language; no specific tapered-element geometry, dimensions, materials, or optical performance figures are given. It also does not verify inventorship, ownership, or legal status beyond the stated assumptions.
Source: https://patents.google.com/patent/[US5598281](/patent/US5598281)/en
Generated 10/1/2026, 9:33:31 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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