Polymerizable oligomeric urethane compositions comprising nanoparticles

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POLYMERIZABLE OLIGOMERIC
URETHANE COMPOSITIONS COMPRISING
NANOPARTICLES

RELATED APPLICATION DATA 5

This application is a continuation of U.S. Ser. No. 11/276, 691, filed Mar. 10, 2006 now U.S. Pat. No. 7,326,448, now allowed which is a continuation-in-part of pending PCT Application No. PCT/US2006/005280, filed Feb. 15, 2006, 10 which claims priority to U.S. Provisional Application Ser. No. 60/653,784, filed Feb. 17, 2005; and this application claims the benefit of U.S. Provisional Application Ser. No. 60/660,962, filed Mar. 11, 2005.

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BACKGROUND

Certain microreplicated optical products, such as described in U.S. Pat. Nos. 5,175,030 and 5,183,597, are commonly referred to as a "brightness enhancing films". 20 Brightness enhancing films are utilized in many electronic products to increase the brightness of a backlit flat panel display such as a liquid crystal display (LCD) including those used in electroluminescent panels, laptop computer displays, word processors, desktop monitors, televisions, video cam- 25 eras, as well as automotive and aviation displays.

Brightness enhancing films desirably exhibit specific optical and physical properties including the index of refraction of a brightness enhancing film that is related to the brightness gain (i.e. "gain") produced. Improved brightness can allow 30 the electronic product to operate more efficiently by using less power to light the display, thereby reducing the power consumption, placing a lower heat load on its components, and extending the lifetime of the product.

Brightness enhancing films have been prepared from high 35 index of refraction monomers that are cured or polymerized, as described for example in U.S. Pat. Nos. 5,908,874; 5,932, 626; 6,107,364; 6,280,063; 6,355,754; as well as EP 1 014113 and WO 03/076528.

Although various polymerizable compositions that are 40 suitable for the manufacture of brightness enhancing films are known, industry would find advantage in alternative compositions.

FIG. 4 is a cross-sectional view of an illustrative microstructured article that has prism elements of varying height;

FIG. 5 is a cross-sectional view of an illustrative microstructured article;

FIG. 6 is a cross-sectional view of an illustrative microstructured article in which the prism elements are of different heights and have their bases in different planes;

FIG. 7 is a cross-sectional view of an illustrative microstructured article;

FIG. 8 is a cross-sectional view of an illustrative microstructured article;

FIG. 9 is a cross-sectional view of an illustrative microstructured article;

FIG. 10 is a schematic view of an illumination device including a turning film;

FIG. 11 is a cross-sectional view of a turning film;

FIG. 12 is a cross-sectional view of another turning film.

While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

DETAILED DESCRIPTION

The term "microstructure" is used herein as defined and explained in U.S. Pat. No. 4,576,850, the disclosure of which is incorporated by reference herein. Thus, it means the configuration of a surface that depicts or characterizes the predetermined desired utilitarian purpose or function of the article having the microstructure. Discontinuities such as projections and indentations in the surface of said article will deviate in profile from the average center line drawn through the microstructure such that the sum of the areas embraced by the surface profile above the center line is equal to the sum of the areas below the line, said line being essentially parallel to the nominal surface (bearing the microstructure) of the article. The heights of said deviations will typically be about +/-0.005 to +/-750 microns, as measured by an optical or electron microscope, through a representative characteristic length of the surface, e.g., 1-30 cm. Said average center line can be piano, concave, convex, aspheric or combinations thereof. Articles where said deviations are of low order, e.g., from +/-0.005+/-0.1 or, preferably, +/-0.05 microns, and said deviations are of infrequent or minimal occurrence, i.e., the surface is free of any significant discontinuities, are those where the microstructure-bearing surface is an essentially "flat" or "smooth" surface, such articles being useful, for example, as precision optical elements or elements with a precision optical interface, such as ophthalmic lenses. Articles where said deviations are of low order and of frequent occurrence include those having anti-reflective microstructure. Articles where said deviations are of high-order, e.g., from +/-0.1 to +/-750 microns, and attributable to microstructure comprising a plurality of utilitarian discontinuities which are the same or different and spaced apart or contiguous in a random or ordered manner, are articles such as retroreflective cube-corner sheeting, linear Fresnel lenses, video discs and brightness enhancing films. The microstructure-bearing surface can contain utilitarian discontinuities of both said low and high orders. The microstructure-bearing surface may contain extraneous or non-utilitarian discontinuities so long as the amounts or types thereof do not signifi