Light redirecting film having varying optical elements

Abstract

The invention relates to a light redirecting film comprising a thin optically transparent substrate having opposite sides, one side of the substrate substantially covered by elongated individual optical elements whose longest dimensions are substantially aligned in a lengthwise direction, wherein the shape of at least some of the optical elements have a visually significant difference, and wherein the layout of optical element shapes and locations is such that objectionable patterns are not visible in the film under standard LCD backlight viewing conditions.

Description

technical field [0001] The present invention generally relates to light redirecting films included in light display assemblies. More particularly, the present invention relates to light redirecting films having individual optical elements arranged in shape and position such that unwanted patterns are not visible. Background technique [0002] The use of various light redirecting films in backlit displays is known. Light redirecting films are typically thin transparent optical films or substrates that redirect light passing through the film so that the distribution of light exiting the film is directed more perpendicular to the film surface. The output light intensity normal to the film divided by the input light intensity normal to the film is called the "on-axis gain" of the film. Typically, light redirecting films have ordered prismatic grooves, lenticular grooves, or pyramids on the light exit surface of the film that alter the angle of the film / air interface of the lig...

AI Technical Summary

Problems solved by technology

However, light redirecting films with variable individual optical elements can have unanticipated problems that are difficult to resolve, including gain loss, gain variation, cosmetic defects and visible unwanted patterns

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