3m Innovative Properties Company

Minnesota Mining and Manufacturing Company

Richard A Miller

Gary Timothy Boyd

Leland Ray Whitney

Kenneth A Aho

Sanford Cobb, Jr

Keith Michael Kotchick

Jeffrey J Melby

Kenneth A Epstein

Todd R Williams

Wade D Kretman

Bettie C Fong

John F Dreyer

Kazuhiko Toyooka

Scott G Theirl

A backlight assembly for use in a transmissive display system is described. The backlight assembly includes a light source that illuminates a light chamber. A transmissive display is positioned adjacent the light chamber so that light that exits the chamber illuminates the transmissive display. The backlight assembly may include one or more specular reflectors and one or more other optical elements to ensure that the light that exits the light chamber has the desired spatial uniformity, polarization, color, and/or angular distribution.

Backlighting transmissive displays

An illumination system for a reflective display is particularly useful for microdisplays that use reflective displays. The light source and the reflective image display unit are mounted in a coplanar manner, thus permitting the light source and the display unit to be mounted on a single board, or even on a single substrate. The display unit may include a first light source directing light generally along a first axis and a reflective image display unit disposed with an optical axis substantially parallel to the first axis. A reflective polarizing film is disposed to direct light from the first light source to the reflective image light display unit.

Illumination system for reflective displays

A backlight assembly for use in a transmissive display system is described. The backlight assembly includes a light source that illuminates a light chamber. A transmissive display is positioned adjacent the light chamber so that light that exits the chamber illuminates the transmissive display. The backlight assembly may include one or more specular reflectors and one or more other optical elements to ensure that the light that exits the light chamber has the desired spatial uniformity, polarization, color, and/or angular distribution

Shaped refractive articles having compound curved surfaces enable a light source to provide substantially uniform illumination of a linear or planar target. The refractive articles can comprise an input edge or face and an output edge or face, the input edge or face having at least one shaped notch or cavity that can at least partially envelop a light source, wherein the notch or cavity has at least two oppositely signed curved portions shaped to provide substantially uniform illumination of a target by the source. The articles can also be optically coupled to and at least partially envelop a light source, and can have an output edge or surface having at least two oppositely signed curved portions shaped to provide substantially uniform illumination of a target region by the source. The shaped articles can be used in, for example, lighting devices, frontlights, backlights and electronic displays.

Linear illumination source

A cavity diffuses light received from a light source so as to produce a uniform light output. The cavity is formed from a unitary structure having one or more portions that diffusely reflect light within the cavity and another portion that transmits the uniform light output. The cavity is a unitary structure, formed from an optically diffusive material, that defines a diffusing cavity having an access aperture. A portion of the unitary structure defines diffusely reflective walls and another portion of the unitary structure defines a diffusely transmitting screen. A portion of the diffusely reflecting walls has a portion that has a thickness being greater than a thickness of the diffusely transmitting screen. The diffusely reflective walls reflect and mix light within the diffusing cavity. The diffusing cavity may be employed in an illuminated display device, having a light source and an imaging device which imposes an image on light received from the cavity.

Unitary light diffusing cavity

A light distribution device having a light-redirecting surface with a plurality of light extraction structures having a riser segment, plateau segment, and facet segment, with adjacent light extraction structures being separated by lands. The light extraction structures improve extraction efficiency, thereby facilitating use of available light from a light source.

Light guide with extraction structures

A wedge-shaped light extractor having a light-redirecting surface with a plurality of projections having a riser segment, a plateau segment, and a facet segment, with land segments flanking the projections. The projections improve extraction efficiency, thereby facilitating use of available light from a light source.

Wedge light extractor with risers

A brightness enhancement article that includes: (a) a transparent, flexible substrate; (b) a first major surface having an array of prisms with blunted or rounded peaks characterized by a chord width, cross-sectional pitch width, and radius of curvature in which the chord width is equal to about 20-40% of the cross-sectional pitch width and the radius of curvature is equal to about 20-50% of the cross-sectional pitch width; and (c) a second major surface characterized by a plurality of light scattering protrusions. The article has a haze value between about 20-60% and a transmission value no greater than about 94% when measured under conditions in which the first surface has a substantially planar topography.

Brightness enhancement article

An optical device having a transparent body and including two prism surfaces formed thereon. The composite structure exhibits two axis stability in that the angular relationship between the input beam and the output beam remains fixed for slight movement of the device about two orthogonal axes.

Directed reflection optical device

A lighting element has a light source positioned so as to provide a beam of light at a grazing angle to a light extractor. The extractor has a plurality linear triangular prism on the side struck by the beam of light. The prisms lie in a smooth arcuate curve.

High aspect ratio lighting element

A passive railroad crossing warning device has two input optical windows that receive light from the headlight of an oncoming locomotive. The light is redirected to an output optical window where a combiner causes it to exit at a predetermined angle to make it visible to motorists approaching the railroad crossing.

Passive railroad crossing warning system

A light fixture has an optical cavity having a first region and multiple additional regions, each of the additional regions, each of the additional regions having an optical window. Light from a light source in the first region is directed out of the optical windows in each of the additional regions.

Multiple cavity light fixture

A reflector has a plurality of Fresnel-type structures, wherein at least some of said Fresnel-type structures have a plurality of active faces, for reflecting light in a plurality of directions.

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Stillwater, MN, United States of America

Richard A Miller