Minnesota Mining and Manufacturing Company

3m Innovative Properties Company

John F Dreyer

Sanford Cobb, Jr

Madeleine B Fleming

Lee A Pavelka

David M Burns

Bruce D Orensteen

Vera L Lightle

Roger H Appeldorn

Richard A Miller

Thomas I Bradshaw

Kenneth A Aho

Neal T Strand

Kenneth M White

Retroreflective articles provide varying retroreflection using a first surface that includes a plurality of light redirecting structures and a second surface that includes retroreflective areas and separation areas. The light redirecting structures on the first surface are preferably arranged relative to the retroreflective areas and the separation areas on the second surface such that a substantial portion of light incident on the light redirecting structures is superimposed on areas of the second surface. At some angles, it is preferred that substantially all of the light is superimposed on either the retroreflective areas or the separation areas, resulting in varying retroreflection from the retroreflective articles. Together, the two optical surfaces of the retroreflective articles provide varying retroreflection of incident light where the variations can be between, e.g., retroreflection or no retroreflection, retroreflection of different colors, retroreflection at different brightness levels, etc. In other words, when subjected to incident light from a steady light source, relative movement between the retroreflective article and the light source will result in variations in retroreflection. When retroreflective articles provide varying retroreflection, the variations or changes will tend to increase the conspicuity of an object or person on which the retroreflective article is located.

Retroreflectors having two optical surfaces and varying retroreflectivity

Imaging articles and methods are disclosed that use dual-axis retroreflective elements such as 90 degree prisms and linear lenticular elements in which the imaging is either superimposed on the imaged object or displaced therefrom. If the imaging is superimposed on the imaged object, it is accomplished by retroreflection. If the imaging is displaced from the imaged object, it may be accomplished by dual axis retroreflection or retrotransmission.

Imaging articles and methods using dual-axis retroreflective elements

A backlight display includes a case having an optical window through which displayed information may be viewed. In addition it includes an electroluminescent panel for providing the backlight. It further includes a structured surface material between the electroluminescent panel and the optical window. The structured surface material has the property of reflecting light entering it while making an angle in a first predetermined group of angles with the axis of the display back to the electroluminescent panel. It further has the property of refracting light entering it while making an angle in a second predetermined group of angles to the axis of the display such that a majority of the light in the second group will exit in an output wedge that is smaller than the input wedge.

Electroluminescent display with brightness enhancement

Retroreflective articles provide modulating retroreflection using a front surface that includes at least first and second areas having different transmission characteristics and a back surface that includes retroreflective areas and separation areas. The first and second areas on the front surface are arranged relative to the retroreflective areas and the separation areas on the back surface such that a substantial portion of light incident on the first areas of the front surface at a first angle is transmitted through the first areas of the front surface to the retroreflective areas on the back surface where it is retroreflected back through the front surface. In addition, a substantial portion of light incident on the first areas of the front surface at a second angle is transmitted through the first areas on the front surface to the separation areas. Together, the front and back surfaces manipulate light such that the retroreflective articles provide modulating retroreflection of incident light where the modulation or variation can be between, e.g., retroreflection or no retroreflection, retroreflection of different colors, retroreflection at different brightness levels, etc. In other words, when subjected to incident light from a steady light source, relative movement between the retroreflective article and the light source can result in variations or modulation in the retroreflection of light from the light source. When retroreflective articles provide modulating retroreflection, the variations or changes tend to increase the conspicuity of the retroreflective articles.

Modulating retroreflective article

Dual axis retroreflective articles and methods of using them are disclosed. The retroreflective articles may combine dual axis retroreflection with three axis retroreflection to provide a steady glow due to the three axis retroreflective portions of the article and also provide intermittent or flashing retroreflection as the plane of retroreflection from the dual axis retroreflector passes through or near the light source. The retroreflective articles may also include dual axis retroreflective structures in combination with sparkling reflective structures, as well as dual axis retroreflective structures in combination with both three axis retroreflective structures and sparkling reflective structures. Methods of use include moving the dual axis retroreflective structures to obtain intermittent or flashing retroreflection.

Dual axis retroreflective articles

A hollow, cylindrical light conduit for transporting light generally longitudinally therethrough and distributing light therealong includes a cylindrical wall member of a transparent material. The wall member has an inner cylindrical smooth surface and an outer cylindrical structured surface having an array of isosceles prisms arranged side by side thereon. The faces of adjacent prisms extend longitudinally along the cylindrical wall member and are aligned at the same desired prism angle relative to one another. The light transporting performance of the light conduit, achieved by total internal reflection, and the light distributing performance of the light conduit, specifically relative to radially aligned, high incident angle longitudinal light rays in planes parallel or near parallel to the prisms, is optimized as a function of the desired prism angle between the faces of adjacent prisms.

Totally internally reflecting light conduit

A line light source includes point light source and a light distribution assembly for transporting light from the point source. A fluorescent colorant is included in the light distribution assembly.

Line light source including fluorescent colorant

A bi-directional line light source having an improved uniformity of brightness along the length of the line light source is achieved using partial reflectors within the line light source. Partial reflectors reflect a portion of incident light and transmit the remaining light. The reflected light from a first light source supplements light from a second light source. Similarly, reflected light from the second light source supplements light from the first light source.

Uniform bi-directional dependent line light source via controlled

The present invention provides a pole light for directing or delivering light in a desired pattern to a surface proximate to the pole light. The present invention also provides a method for lighting a plurality of desired regions on a surface in a precise and predetermined pattern useful, for example, as a traffic management and guidance system.

Pole light having a programmable footprint

A conspicuity enhancer includes a case defining an optical cavity having an output optical window. The conspicuity enhancer also includes first and second linear light sources forming a V. Each linear light source has a light emitting device that inserts light into one end of the light source. The other end of each light source is attached to the case such that each linear light source is in optical communication with the optical cavity.

Conspicuity enhancer

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 line light source has a light-emitting element that emits light into an insertion conduit. A light absorber absorbs light that makes greater than a predetermined angle with the axis of the light conduit.

Line light source

A light source substantially longer than its diameter exhibits two different optical characteristics, such as two different colors, depending upon the direction along the long axis from which it is viewed. The light source comprises a light conduit employing total internal reflection and two illumination sources directing light into the light conduit from opposite ends.

Direction dependent line light source

A high aspect ratio light fixture has an optical window with a light extraction film therein. The light extraction film has a plurality of linear prisms facing the interior of the light fixture. In one embodiment of the invention the prisms are triangular in shape while in another they are four sided.

High aspect ratio light fixture and film for use therein

An overhead projector includes a projection head which contains a pivoting mirror and a pivoting projection lens interconnected by a linkage. Rotation of the mirror causes rotation and translation of the projection lens and automatically corrects for Scheimpflug distortion and loss of overall focus of the projected image.

Growing community of inventors

North Oaks, MN, United States of America

John F Dreyer