Daylight redirecting window film employing embedded microstructures
A daylight redirecting window film having a layered structure with a total thickness of less than one millimeter and having a first optically transmissive film, a second optically transmissive film approximately coextensive with the first optically transmissive film, an intermediate layer of a relatively soft optically transmissive material disposed between the first and second optically transmissive films, a parallel array of linear three-dimensional structures formed in a space between the first and second optically transmissive films, a layer of an optically transmissive adhesive coating a surface of the first optically transmissive film, and a two-dimensional pattern of light scattering surface microstructures formed in an outer surface of the second optically transmissive film. The parallel array of linear three-dimensional structures defines a parallel array of linear channels, and each of the linear three-dimensional structures has a total internal reflection wall extending transversely through a portion of the layered structure.
1. A daylight redirecting window film having a layered structure with a total thickness of less than one millimeter, comprising:
a first optically transmissive film;
a second optically transmissive film approximately coextensive with the first optically transmissive film;
an intermediate layer of a relatively soft optically transmissive material disposed between the first and second optically transmissive films;
a parallel array of linear three-dimensional structures formed in a space between the first and second optically transmissive films;
a layer of an optically transmissive adhesive coating a surface of the first optically transmissive film; and
a two-dimensional pattern of light scattering surface microstructures formed in an outer surface of the second optically transmissive film,
wherein the parallel array of linear three-dimensional structures defines a parallel array of linear channels each having a width of less than 50 micrometers, wherein each of the parallel array of linear three-dimensional structures has a first wall extending transversely through a portion of the layered structure and configured to reflect light using a total internal reflection, an opposing second wall, and a third wall joining the first and second walls.
2. The daylight redirecting window film of claim 1 , wherein at least one of the linear channels has an average width of about 20 micrometers, and wherein each of the linear channels extends from a first edge of the layered structure to an opposing second edge of the layered structure.
3. The daylight redirecting window film of claim 1 , wherein the layered structure is configured to be attached to an indoor-facing surface of a window of a building façade using the optically transmissive adhesive coating and further configured to mask and/or blur a view of objects through a portion of the window.
4. The daylight redirecting window film of claim 1 , wherein the layered structure is configured to be attached to an indoor-facing surface of a window of a building façade using the optically transmissive adhesive coating and further configured to have one or more edges sealed using an air and/or moisture impermeable encapsulating resin.
5. The daylight redirecting window film of claim 1 , wherein the layered structure is adapted to be operably retained in a bent or rolled configuration.
6. The daylight redirecting window film of claim 1 , wherein the layered structure is configured to be attached to a light transmitting surface of a skylight structure.
7. The daylight redirecting window film of claim 1 , wherein the width is less than 20 micrometers, wherein the layered structure is configured to be attached to an indoor-facing surface of a window of a building façade with a horizontal orientation of the parallel array of linear channels, and is further configured for redirecting daylight to a ceiling.
8. The daylight redirecting window film of claim 1 , wherein a distance between adjacent ones of the linear three-dimensional structures is substantially less than a depth of the linear channels.
9. The daylight redirecting window film of claim 1 , wherein a distance between adjacent ones of the linear three-dimensional structures is less than a depth of the linear channels by at least ten times.
10. The daylight redirecting window film of claim 1 , wherein the layered structure is configured for blocking ultra-violet rays.
11. The daylight redirecting window film of claim 1 , wherein a distance between adjacent ones of the linear three-dimensional structures is less than a depth of the linear channels by at least ten times, wherein the daylight redirecting window film is configured to be attached to an indoor-facing surface of a window of a building façade with a horizontal orientation of the parallel array of linear channels, and is further configured for redirecting daylight to a ceiling.
12. The daylight redirecting window film of claim 1 , wherein a distance between adjacent ones of the linear three-dimensional structures is less than a depth of the linear channels, wherein the layered structure is configured to have one or more edges sealed using an air and/or moisture impermeable encapsulating resin, and is further configured to be attached to an indoor-facing surface of a window of a building façade with a horizontal orientation of the parallel array of linear channels so as to redirect at least a portion of incident daylight to a ceiling.
13. The daylight redirecting window film of claim 1 , wherein a distance between adjacent ones of the linear three-dimensional structures is less than a depth of the linear channels, wherein the layered structure is configured to have one or more edges sealed using an air and/or moisture impermeable encapsulating resin, is further configured to be attached to an indoor-facing surface of a window of a building façade with a horizontal orientation of the parallel array of linear channels so as to redirect at least a portion of incident daylight to a ceiling, and is further configured to mask and/or blur a view of objects through a portion of the window.
14. The daylight redirecting window film of claim 1 , wherein a distance between adjacent ones of the linear three-dimensional structures is less than a depth of the linear channels, wherein the layered structure is configured to have one or more edges sealed using an air and/or moisture impermeable encapsulating resin, is further configured to be attached to an indoor-facing surface of a window of a building façade with a horizontal orientation of the parallel array of linear channels so as to redirect at least a portion of incident daylight to a ceiling, and is further configured to is configured for blocking ultra-violet rays and blur a view of objects through a portion of the window.
15. The daylight redirecting window film of claim 1 , wherein a durometer hardness of a material of the intermediate layer is less than 95 Shore A, wherein a distance between adjacent ones of the linear three-dimensional structures is less than a depth of the linear channels, wherein the layered structure is configured to have one or more edges sealed using an air and/or moisture impermeable encapsulating resin, is further configured to be attached to an indoor-facing surface of a window of a building façade with a horizontal orientation of the parallel array of linear channels so as to redirect at least a portion of incident daylight to a ceiling, and is further configured to mask and/or blur a view of objects through a portion of the window.
16. A daylight redirecting window film having a layered structure, comprising:
a first optically transmissive film;
a second optically transmissive film approximately coextensive with the first optically transmissive film;
an intermediate layer of a relatively soft optically transmissive material disposed between the first and second optically transmissive films;
a parallel array of linear three-dimensional structures formed in a space between the first and second optically transmissive films;
a layer of an optically transmissive adhesive coating a surface of the first optically transmissive film; and
a two-dimensional pattern of light scattering surface microstructures formed in an outer surface of the second optically transmissive film,
wherein the parallel array of linear three-dimensional structures defines a parallel array of linear channels each having a width of less than 50 micrometers, wherein each of the parallel array of linear three-dimensional structures has a first wall extending transversely through a portion of the layered structure and configured to reflect light using a total internal reflection, an opposing second wall, and a third wall joining the first and second walls, and wherein a combined thickness of the first optically transmissive film, the second optically transmissive film, the intermediate layer, and the layer of the optically transmissive adhesive is less than one millimeter.
17. A method of making a daylight redirecting window film, comprising:
providing a first optically transmissive film;
providing a second optically transmissive film approximately coextensive with the first optically transmissive film;
disposing an intermediate layer of a relatively soft optically transmissive material between the first and second optically transmissive films;
forming a parallel array of linear channels in a space between the first and second optically transmissive films, each of the linear channels having a width of less than 50 micrometers, a first wall configured to reflect light using a total internal reflection, and an opposing second wall; and
coating a surface of the first optically transmissive film with a layer of an optically transmissive adhesive,
wherein an outer surface of the second optically transmissive film comprises a two-dimensional pattern of light scattering surface microstructures, and wherein a combined thickness of the first optically transmissive film, the second optically transmissive film, the intermediate layer of the relatively soft optically transmissive material, and the layer of the optically transmissive adhesive is less than one millimeter.
18. The method of making a daylight redirecting window film of claim 17 , wherein the daylight redirecting window film is configured to be attached to an indoor-facing surface of a window of a building façade with a horizontal orientation of the parallel array of linear channels and is further configured for redirecting daylight to a ceiling.
19. The method of making a daylight redirecting window film of claim 17 , wherein the daylight redirecting window film is configured to be attached to an indoor-facing surface of a window of a building façade with a horizontal orientation of the parallel array of linear channels, is further configured for redirecting daylight to a ceiling, and is further configured for blocking ultra-violet rays.