Glare management of reflective and thermoreflective surfaces

• US 8,634,137 B2
• Filed: 04/23/2009
• Issued: 01/21/2014
• Est. Priority Date: 04/23/2008
• Status: Expired due to Fees

• Current Assignee: Ravenbrick, LLC
• Original Assignee: Ravenbrick, LLC
• Inventors: Powers, Richard M., McCarthy, Wil
• Primary Examiner(s): FONT, FRANK G
• Application Number:
  US12/429,092
• Publication Number:
  US 20090268273A1
• Time in Patent Office: 1,734 Days
• Field of Search: 359/485.01, 359/485.05, 359/485.07, 359/488.01, 359/490.01, 359/493.01, 359/494.01, 359591-599, 359601-602, 359/609, 359/613, 359/614, 359/890
• US Class Current: 359/485.01
• CPC Class Codes: B32B 2307/42 Polarizing, birefringent, filtering
• CPC Class Codes: B32B 2551/00 Optical elements
• CPC Class Codes: B32B 37/18 involving the assembly of discrete sheets or panels only
• CPC Class Codes: B32B 38/1808 characterised by the laying up of the layers
• CPC Class Codes: G02B 27/281 used for attenuating light intensity, e.g. comprising rotatable polarising elements
• CPC Class Codes: G02B 5/0231 the surface having microprismatic or micropyramidal shape macroscopic prism arrays G02B5/045
• CPC Class Codes: G02B 5/0242 by means of dispersed particles
• CPC Class Codes: G02B 5/0247 by means of voids or pores
• CPC Class Codes: G02B 5/0252 using holographic or diffractive means
• CPC Class Codes: G02B 5/0268 characterized by the fabrication or manufacturing method
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02B 5/0284 used in reflection
• CPC Class Codes: G02B 5/0289 used as a transflector
• CPC Class Codes: G02B 5/0294 adapted to provide an additional optical effect, e.g. anti-reflection or filter
• CPC Class Codes: G02B 5/3058 comprising electrically conductive elements, e.g. wire grids, conductive particles
• CPC Class Codes: G02F 1/0147 based on thermo-optic effects G02F1/132 takes precedence
• CPC Class Codes: G02F 1/133545 Dielectric stack polarisers
• CPC Class Codes: G02F 1/133548 Wire-grid polarisers
• CPC Class Codes: G02F 2201/346 distributed (Bragg) reflector
• CPC Class Codes: G02F 2201/38 Anti-reflection arrangements

Abstract

The reflectivity and transmissivity of building and vehicle surfaces is maintained while employing partial, variable, selective, or asymmetric diffusers between a surface and an external light source such that the reflected light is diffused to produce a reduction in glare, while minimally effecting the specular or collimated transmission (if any) of light through the surface. Glare is also reduced by utilizing diffuser devices that reflect light in a temperature dependent manner.

Claims

1. An energy-efficient device that reduces glare from reflection of incident light comprising a first reflective polarizer;

a second reflective polarizer;

a thermochromic depolarizer positioned between the first reflective polarizer and the second polarizer;

a transparent substrate affixed to the second reflective polarizer; and

an at least partially diffusive filter affixed to the first reflective polarizer.

2. The energy-efficient device of claim 1 further comprising incorporating an electrochromic depolarizer in conjunction with the thermochromic depolarizer.

3. The energy-efficient device of claim 1, wherein the at least partially diffusive filter is a variable diffuser with a light scattering ability controllable by one or more external conditions.

4. The energy-efficient device of claim 3, wherein the one or more external conditions comprise a temperature and/or an applied electric field.

5. The energy-efficient device of claim 3, wherein the variable diffuser further comprises a thermodiffusive filter that is mostly transparent within a first temperature range and that is mostly diffusive within a second temperature range.

6. The energy efficient device of claim 5, wherein the thermodiffusive filter comprises

a first transparent material;

and

beads or bubbles of a second transparent material, wherein

within a first temperature range, an index of refraction of the first transparent material is substantially the same as an index of refraction of the second transparent material; and

within a second temperature range, one or both of the index of refraction of the first transparent material and the index of refraction of the second transparent material change such that there is a substantial mismatch between the index of refraction of the first transparent material and the index of refraction of the second transparent material.

7. The energy efficient device of claim 6, wherein the first transparent material and the second transparent material are selected such that the thermodiffusive filter functions as a thermochromic diffusive Bragg reflector.

8. The energy-efficient device of claim 1, wherein the partially diffusive filter is a selective diffuser that only diffuses light of particular wavelengths or particular polarities.

9. The energy-efficient device of claim 1, wherein the partially diffusive filter is an asymmetric diffuser that scatters light passing through the device in a first direction more strongly than light passing through the device in a second direction.