Light-redirecting retractable window covering

Patent metadata

Field	Value
Publication number	US-10577859-B2
Application number	US-201715458006-A
Country	US
Kind code	B2
Filing date	Mar 13, 2017
Priority date	Jun 10, 2014
Publication date	Mar 3, 2020
Grant date	Mar 3, 2020

Abstract

A retractable window covering for natural illumination of building interiors by redirecting the incident daylight at angles that promote its deeper penetration into the interior space. The window covering comprises an optically transmissive, flexible polymeric sheet having reflective surfaces incorporated into its material and configured to redirect at least a portion of light propagating through the sheet towards a desired direction. The window covering is operable from a closed to an open position so as to increase or decrease the amount of redirected and/or admitted light.

First claim

What is claimed is:

1. A retractable window covering, comprising:
a roller;
a flexible translucent sheet having a first end and an opposing second end, the first end being windingly received around the roller;
the translucent sheet having a layered structure comprising an optically transmissive light redirecting sheet and an optically transmissive light diffusing sheet bonded to a broad-area surface of the light redirecting sheet using an optically transmissive adhesive;
a parallel array of total internal reflection (TIR) channels formed in the broad-area surface and longitudinally extending between a first edge and an opposing second edge of the light redirecting sheet, each of the TIR channels defining an optical surface configured to reflect light propagating transversely through the light redirecting sheet using a total internal reflection; and
a plurality of light deflecting surface microstructures formed in an outer surface of the light diffusing sheet and configured to randomize emergence angles of light rays passing through the light diffusing sheet,
wherein the TIR channels are dimensioned such that at least a portion of incident light received on a surface of the light redirecting sheet is intercepted and redirected along a direction of propagation that is different than a direction of incidence.

2. The retractable window covering of claim 1 , comprising a second roller configured for windingly receiving the second end of the flexible translucent sheet.

3. The retractable window covering of claim 1 , comprising a rigid bar attached to the second end of the flexible translucent sheet.

4. The retractable window covering of claim 1 , wherein the material of the light redirecting sheet comprises plasticized polyvinyl chloride.

5. The retractable window covering of claim 1 , wherein at least one of the TIR channels is filled with an optically clear material having a different refractive index than the material of the light redirecting sheet.

6. The retractable window covering of claim 1 , wherein at least one of the TIR channels comprises a mirrored surface.

7. The retractable window covering of claim 1 , further comprising one or more channels crossed at a right angle with respect to the parallel array of TIR channels.

8. The retractable window covering of claim 1 , wherein a transverse cross-section of at least one of the TIR channels has the form of a wedge having concave walls.

9. The retractable window covering of claim 1 , wherein the light redirecting sheet is configured for a generally unimpeded transversal light passage along at least one viewing direction.

10. The retractable window covering of claim 1 , wherein the flexible translucent sheet comprises a light filtering feature configured to block infra-red or ultra-violet rays.

11. The retractable window covering of claim 1 , wherein the optical surface is planar and oriented perpendicular to a surface of the light redirecting sheet.

12. The retractable window covering of claim 1 , wherein the optical surface has a curved shape and wherein at least a portion of the optical surface is disposed at an angle with respect to a normal to a broad-area surface of the light redirecting sheet.

13. The retractable window covering of claim 1 , wherein one or more side walls of the TIR channels at a first location of the light redirecting sheet make a first dihedral angle with respect to a surface of the light redirecting sheet and one or more side walls of the TIR channels at a second location of the light redirecting sheet make a second dihedral angle with respect to the surface of the light redirecting sheet, the second dihedral angle being different than the first dihedral angle.

14. The retractable window covering of claim 1 , wherein a root mean square surface profile roughness parameter of the optical surface is at most about 60 nanometers at a sampling length of between 20 and 100 micrometers.

15. The retractable window covering of claim 1 , wherein a root mean square surface profile roughness parameter of the optical surface is at least about 10 nanometers and at most about 60 nanometers at a sampling length of between 20 and 100 micrometers.

16. The retractable window covering of claim 1 , wherein the thickness of the flexible translucent sheet is between 200 micrometers and 2 millimeters.

17. The retractable window covering of claim 1 , wherein the flexible translucent sheet has at least one optically transparent section.

18. The retractable window covering of claim 1 , wherein the flexible translucent sheet has two or more sections having different optical properties.

19. A method for illuminating a building interior with daylight, comprising:
providing a retractable window covering attachable to an opening in a building façade, said window covering including a flexible translucent sheet windingly received around at least one roller, said flexible translucent sheet comprising a light redirecting layer and a light diffusing layer bonded to the light redirecting layer using an optically transmissive adhesive, said light redirecting layer comprising a plurality of total internal reflection surfaces and being configured to redirect at least off-axis light rays at a bend angle being greater than the angle of incidence using a total internal reflection, said light diffusing layer having light deflecting surface microstructures formed in a surface facing away from the light redirecting layer; and
operating said retractable window covering from a closed to an open position in response to a demand for redirecting daylight received upon said opening in a building façade.

20. A method for making a retractable light redirecting window covering, comprising:
providing a thin and flexible sheet an optically clear polymeric material;
forming a plurality of parallel channels in a broad-area surface of the thin and flexible sheet, at least one of said channels defining an optical surface having a root-mean-square roughness parameter of at least 10 nanometers and at most 60 nanometers on a sampling length between 20 and 100 micrometers;
bonding a light diffusing film to the broad-area surface using an optically transmissive adhesive so as to form a layered sheet-form structure, said light diffusing film having light deflecting surface microstructures; and
windingly receiving at least one end of the layered sheet-form structure around a roller,
wherein the light redirecting window covering is operable from a closed to an open position using the roller.

Assignees

• Vasylyev Sergiy
• Svv Tech Innovations Inc

Inventors

• Vasylyev Sergiy

Classifications

• F21S11/007

  characterised by the means for transmitting light into the interior of a building · CPC title

• E06B2009/2411

  Coloured fluid flow for light transmission control · CPC title

• E06B2009/2417

  Light path control; means to control reflection · CPC title

• E06B9/42 Primary

  Parts or details of roller blinds, e.g. suspension devices, blind boxes (brackets or adjustable mountings for roller blinds and drawable curtains A47H1/13) · CPC title

• E06B2009/2405

  Areas of differing opacity for light transmission control · CPC title