Optical sheets suitable for spreading light
First Claim
1. An optical sheet suitable for spreading light, in which a first major surface of the sheet is a structured surface comprising an array of prisms such that, if the second major surface of the sheet is substantially smooth, a normally-incident beam of light that enters the sheet through the second major surface and leaves through the array of prisms will be spread by the latter;
- wherein the array comprises;
(a) a plurality of reflection prisms selected to deviate the normally-incident light through different angles and a plurality of refraction prisms selected to deviate the normally-incident light through different angles, in which successive reflection prisms are separated by at least one refraction prism;
or (b) a non-ordered arrangement of a plurality of reflection prisms selected to deviate the normally-incident light through different angles;
or (c) a non-ordered arrangement of a plurality of refraction prisms selected to deviate the normally-incident light through different angles;
in which each refraction prism deviates the normally-incident light only by refraction at a prism facet as the light leaves the sheet through the first major surface and each reflection prism deviates the normally-incident light by total internal reflection within the prism before the light leaves the sheet through the first major surface.
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0 Petitions
Accused Products
Abstract
An optical sheet (25) for spreading light has a substantially smooth surface (27), and a structured surface (28) comprising an array of prisms (30, 31). A beam of light that is to be spread is directed through the film from the smooth surface. Some of the prisms (termed “refraction prisms”) deviate normally-incident light only by refraction at a prism facet as the light leaves the film while others (termed “reflection prisms”) deviates normally-incident light by total internal reflection within the prism before the light leaves the film. There are a plurality of reflection prisms (30) selected to deviate normally-incident light through different angles and a plurality of refraction prisms (31) selected to deviate the normally-incident light through different angles, and they are arranged, preferably in a non-ordered manner, so that successive reflection prisms are separated by at least one refraction prism. In alternative embodiments, the structured surface comprises a non-ordered arrangement of a plurality of reflection prisms selected to deviate normally-incident light through different angles, or a non-ordered arrangement of a plurality of refraction prisms selected to deviate normally-incident light through different angles.
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Citations
17 Claims
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1. An optical sheet suitable for spreading light, in which a first major surface of the sheet is a structured surface comprising an array of prisms such that, if the second major surface of the sheet is substantially smooth, a normally-incident beam of light that enters the sheet through the second major surface and leaves through the array of prisms will be spread by the latter;
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wherein the array comprises;
(a) a plurality of reflection prisms selected to deviate the normally-incident light through different angles and a plurality of refraction prisms selected to deviate the normally-incident light through different angles, in which successive reflection prisms are separated by at least one refraction prism;
or(b) a non-ordered arrangement of a plurality of reflection prisms selected to deviate the normally-incident light through different angles;
or(c) a non-ordered arrangement of a plurality of refraction prisms selected to deviate the normally-incident light through different angles;
in which each refraction prism deviates the normally-incident light only by refraction at a prism facet as the light leaves the sheet through the first major surface and each reflection prism deviates the normally-incident light by total internal reflection within the prism before the light leaves the sheet through the first major surface. - View Dependent Claims (2, 3, 4)
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5. An optical sheet suitable for spreading light, in which a first major surface of the sheet is a structured surface comprising an array of prisms and the second major surface of the sheet is substantially smooth, whereby a normally-incident beam of light that enters the sheet through the second major surface and leaves through the array of prisms will be spread by the latter;
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wherein the array comprises;
a non-ordered arrangement of a plurality of reflection prisms selected to deviate the normally-incident light through different angles and a plurality of refraction prisms selected to deviate the normally-incident light through different angles, in which successive reflection prisms are separated by at least one refraction prism;
in which each refraction prism deviates the normally-incident light only by refraction at a prism facet as the light leaves the sheet through the first major surface and each reflection prism deviates the normally-incident light by total internal reflection within the prism before the light leaves the sheet through the first major surface. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification