Light enhancing structures with a plurality of arrays of elongate features
View Patent ↗Various embodiments comprise light recycling films comprising an array of parallel ridges and grooves that form prisms that selectively reflect or transmit light. In some embodiments, the light recycling film may be used in displays that include spatial light modulators comprising a plurality of pixels. The light recycling film can limit the field-of-view of the display and enhance the luminance within that field-of-view. Various embodiments comprising multiple arrays of ridges and/or grooves can enhance uniformity of illumination of the pixels in the spatial light modulator and reduce Moiré effects.
1. An optical member comprising an array of total internal reflection structures, the optical member comprising:
an optically transmissive film having a surface;
a first plurality of non-intersecting elongate features formed in the surface; and
a second plurality of non-intersecting elongate features formed in the surface, the first plurality of non-intersecting elongate features being oriented at an angle with respect to the second plurality of non-intersecting elongate features that is less than 30°,
wherein each of the non-intersecting elongate features in the first plurality extends across the multiple non-intersecting elongate features in the second plurality thereby defining the total internal reflection structures, and at least one of the total internal reflection structures comprises a prism having facets having rounded edges,
wherein at least a portion of the second plurality of nonintersecting elongate features has a height or depth that is smaller than a height or depth of at least a portion of the first plurality of non-intersecting elongate features but that is greater than 50% of the height or depth of the portion of the first plurality of non-intersecting elongate features,
wherein a thickness of the optically transmissive film is selected based at least partly on a pitch of at least some non-intersecting elongate features of the first plurality or the second plurality so as to provide a desired on-axis luminance enhancement of light passing through the film.
2. The optical member of claim 1 , wherein at least one of the total internal reflection structures comprises a prism having planar facets.
3. The optical member of claim 1 , wherein each of the facets in the prisms has substantially the same projected area.
4. The optical member of claim 1 , further comprising a third plurality of non-intersecting elongate features.
5. The optical member of claim 1 , wherein the pitch of at least some non-intersecting elongate features in the second plurality is unequal.
6. The optical member of claim 1 , wherein the first and second plurality of non-intersecting elongate features are arranged non-symmetrically.
7. The optical member of claim 1 , wherein the optically transmissive film has a rough surface.
8. The optical member of claim 1 , wherein at least one of the elongate features includes a first pair of faceted edges and a second pair of faceted edges.
9. The optical member of claim 8 , wherein the first and second pairs of faceted edges are formed using a cutter corresponding to a shape of the features to be formed.
10. The optical member of claim 1 , wherein the non-intersecting elongate features comprise grooves, and the grooves are formed using a cutting tool that defines a groove root parallel to a plane of the surface of the film and that oscillates within a plane containing the groove root.
11. The optical member of claim 1 , wherein the non-intersecting elongate features comprise grooves, and the grooves are formed using a cutting tool that defines a groove root parallel to a plane of the surface of the film and that oscillates transverse to the direction of the groove root.
12. The optical member of claim 1 , wherein an index of refraction of the film is selected to provide a desired on-axis luminance enhancement of light passing through the film.
13. The optical member of claim 1 , wherein the optical member is used in an LCD television or a monitor for a handheld device.
14. The optical member of claim 1 , wherein the film is a composite light recycling film.
15. The optical member of claim 1 , wherein stress is used to introduce an aberration in the structure of the features in at least a portion of the film.
16. The optical member of claim 1 , wherein the angle is less than 10°.