An article, including a transparent sheet having a first side with a structured surface The structured surface includes microprisms thereon, the microprisms being part of a microprism array on the structured surface. Each one of the microprisms are part of adjacent pairs of the microprisms, such that for each one of the adjacent pairs: the first microprism has a first lateral face, a second lateral face, and a third lateral face, the second microprism has a first lateral face, a second lateral face, and a third lateral face, and there is a continuous surface transition with a maintenance of surface continuity between the second lateral face of the first microprism and the third lateral face of the second microprism, without the presence of a seam, ridge, gap or tooling line.

A method for manufacturing a mold for a retroreflective element, the mold having plural polygonal faces having a common vertex, the method including the steps of: roughing of a polygonal face in which cutting is carried out such that a predetermined cutting amount in a finishing process is left with respect to a desired shape; and finishing of the polygonal face in which a blade portion is made to move relatively towards the vertex while an angle of relief of the blade portion is kept within 1 degree so as to carry out cutting of the predetermined cutting amount, wherein a depth of cut for each one-time cutting operation is 2 micrometers or smaller, and the movement of the blade portion is a combination of a motion towards the vertex and an oscillation.

An article, including a transparent sheet having a first side with a structured surface The structured surface includes microprisms thereon, the microprisms being part of a microprism array on the structured surface. Each one of the microprisms are part of adjacent pairs of the microprisms, such that for each one of the adjacent pairs: the first microprism has a first lateral face, a second lateral face, and a third lateral face, the second microprism has a first lateral face, a second lateral face, and a third lateral face, and there is a continuous surface transition with a maintenance of surface continuity between the second lateral face of the first microprism and the third lateral face of the second microprism, without the presence of a seam, ridge, gap or tooling line.

Various geometries are described for forming retroreflective structures in polymeric sheets or films. The geometries enable venting of volatile gases that can otherwise become trapped between the embossing surface and the polymeric sheet or film. The geometries are incorporated in tooling belts or other pattern forming surfaces.

Method of manufacturing articles, including providing a substrate having a surface, forming first and second sets of first and second grooves in the surface, respectively, the first grooves parallel to each other along a same first direction across the surface and each of the first grooves including a repeating interleaved pattern of at least two first zones and at least two second zones and a maximum depth of the first zones greater than a maximum depth of the second zones, and the second grooves parallel to each other along a same second direction across the surface, the second direction being substantially perpendicular to the first direction, the second grooves passing through second zones of the first grooves, where a groove pattern is thereby formed on the surface, the groove pattern including microprisms. Articles including a substrate surface with such groove patterns or inverted groove patterns including microprisms or inverted microprisms.

Methods of making tiled articles and molds used to make retroreflective articles. The methods include forming a prism array on a master substrate and forming a replica of the master. A reference edge is formed on the replica, thereby reducing the size of the prism array, yet maintaining a lateral dimension of the replica to maintain ease of handling of the replica. The replica is copied and the reference edge on the copied tiles are exposed, such that the reference edge can be mated and secured face-to-face with a reference edge on other tiles in order to form a tiled article. The tiled article is used as a mold to produce retroreflective articles or can be further duplicated and mated to form larger tiled articles to be used as molds. Tiled articles used as molds and retroreflective articles produced from the molds are also disclosed.

A retroreflector includes an arrangement of triples, each having three side surfaces, which are disposed in the manner of a cube corner and stand approximately perpendicular on one another. The retroreflector can be produced from a carrier material by injection molding. An optical silicone resin is used as the carrier material. The retroreflector is based on triple mirrors that are both easily unmolded from a die and easily applied to curved surfaces even after unmolding or are usable for reflection of ultraviolet light.

An article, including a substrate having a surface with a groove pattern including microprisms thereon. The groove pattern includes a first set of first grooves intersecting with a second set of second grooves, the first grooves are parallel to each other along a same first direction across the groove pattern, and each of the first grooves include a plurality of repeating variable depth zones. Each of the variable depth zones include: a dive section having a first maximum depth, Z.sub.D2, and a rise section having a second maximum depth, Z.sub.R2. The second grooves are parallel to each other along a same second direction across the surface, the second direction being substantially perpendicular to the first direction.

A retroreflector includes an arrangement of triples, each having three side surfaces, which are disposed in the manner of a cube corner and stand approximately perpendicular on one another. The retroreflector can be produced from a carrier material by injection molding. An optical silicone resin is used as the carrier material. The retroreflector is based on triple mirrors that are both easily unmolded from a die and easily applied to curved surfaces even after unmolding or are usable for reflection of ultraviolet light.

Method of manufacturing articles, including providing a substrate having a surface, forming first and second sets of first and second grooves in the surface, respectively, the first grooves parallel to each other along a same first direction across the surface and each of the first grooves including a repeating interleaved pattern of at least two first zones and at least two second zones and a maximum depth of the first zones greater than a maximum depth of the second zones, and the second grooves parallel to each other along a same second direction across the surface, the second direction being substantially perpendicular to the first direction, the second grooves passing through second zones of the first grooves, where a groove pattern is thereby formed on the surface, the groove pattern including microprisms. Articles including a substrate surface with such groove patterns or inverted groove patterns including microprisms or inverted microprisms.