US 5461547

Patent Overview — US 5,461,547 A

Title: Flat panel display lighting system
Patent number: US 5,461,547 A
Application number: US 08/095,753
Inventors: Werner W. Ciupke, William F. Redmond, Richard E. DuNah
Original assignee: Precision Lamp Inc.
Current assignee (per listing): Miyakawa Corp; Credit Managers Association of California
Priority/filing date: 1993-07-20
Publication (grant) date: 1995-10-24
Legal status (as listed): Expired – Lifetime; anticipated expiration 2013-07-20
Source: https://patents.google.com/patent/US5461547/en

Purpose. The invention relates generally to lighting systems for illuminating flat panel displays such as liquid crystal displays (LCDs), and more particularly to a system employing a thin flat light guide with microgrooves formed on one major surface for extracting light introduced into the light guide. The patent notes that known edge-lit large-area lighting systems generally lack uniform thickness, which is undesirable for backlighting pagers, hand-held computers, organizers and similar LCDs.

Plain-language scope. A thin, flat, transparent light guide has a first planar major surface and a second parallel major surface carrying closely spaced parallel microgrooves. Surfaces of those grooves internally reflect light introduced into the guide in a direction substantially perpendicular to the groove axes, directing it toward the other major surface, where it is emitted. Embodiments add a reflector adjacent the faceted surface, a reflector at the light pipe end, and a diffuser or brightness-enhancing film receiving emitted light. A described example uses a one-millimeter-thick pipe matched to miniature incandescent sources, with a U-shaped reflector and index-matching material that may be tinted for colored lighting. V-groove depths of 2.5–10 µm, spacing of 100–250 µm, and facet angles of 45–55 degrees are described, with spacing optionally varied along the length for uniformity.

Not established by the excerpt. The supplied text is excerpted, so complete claim language, the full number of claims, all drawing details, the complete specification, and the full prior-art discussion are not available. It also does not establish prosecution history, the accuracy of the listed assignees, or any legal conclusions about status or scope.