Optical filter comprising a variable transmittance layer

• US 9,588,358 B2
• Filed: 05/29/2013
• Issued: 03/07/2017
• Est. Priority Date: 05/29/2012
• Status: Active Grant

• Current Assignee: Solutia Canada, Inc. (Eastman Chemical Company)
• Original Assignee: Switch Materials, Inc.
• Inventors: Branda, Neil Robin, Erno, Zachary Bryce, Finden, Jeremy Graham, Lam, Duhane, Loo, Charles Joseph Gongming, Sargent, Jonathan Ross, Smit, Matthew Paul, Von Hahn, Peter Alexander, Wiggin, Douglas Malcolm
• Primary Examiner(s): HASAN, MOHAMMED A
• Application Number:
  US14/404,581
• Publication Number:
  US 20150109651A1
• Time in Patent Office: 1,378 Days
• Field of Search: 359/238, 359/239, 359/722, 359/642, 359/885, 359/891
• US Class Current: 1/1
• CPC Class Codes: B29D 11/00634 Production of filters
• CPC Class Codes: B32B 17/10486 photochromic
• CPC Class Codes: B32B 17/10513 Electrochromic layer
• CPC Class Codes: B32B 17/10633 Infrared radiation absorbing or reflecting agents
• CPC Class Codes: B32B 17/10761 containing vinyl acetal
• CPC Class Codes: B32B 2307/402 Coloured
• CPC Class Codes: B32B 2307/42 Polarizing, birefringent, filtering
• CPC Class Codes: B32B 2315/08 Glass
• CPC Class Codes: B32B 2419/00 Buildings or parts thereof walls, panels B32B2607/00
• CPC Class Codes: B32B 2551/00 Optical elements
• CPC Class Codes: B32B 2605/006 Transparent parts other than made from inorganic glass, e.g. polycarbonate glazings
• CPC Class Codes: B32B 2605/08 Cars
• CPC Class Codes: B32B 37/12 characterised by using adhesives
• CPC Class Codes: B60J 3/04 adjustable in transparency
• CPC Class Codes: E06B 2009/2417 Light path control; means to control reflection
• CPC Class Codes: E06B 2009/2464 featuring transparency control by applying voltage, e.g. LCD, electrochromic panels
• CPC Class Codes: E06B 9/24 Screens or other constructions affording protection against light, especially against sunshine; Similar screens for privacy or appearance; Slat blindsoperating, guiding or securing devices or arrangements for roll-type closures E06B9/56; free-hanging flexible screens A47H23/00
• CPC Class Codes: G02B 5/208 for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation
• CPC Class Codes: G02B 5/23 Photochromic filters
• CPC Class Codes: G02C 7/10 Filters, e.g. for facilitating adaptation of the eyes to the dark; Sunglasses
• CPC Class Codes: G02C 7/101 : having an electro-optical light valve electro-optical elements per se G02F
• CPC Class Codes: G02C 7/102 : Photochromic filters
• CPC Class Codes: G02F 1/0102 : Constructional details, not otherwise provided for in this subclass
• CPC Class Codes: G02F 1/157 : Structural association of cells with optical devices, e.g. reflectors or illuminating devices
• CPC Class Codes: G02F 2203/05 : wavelength dependent
• CPC Class Codes: G02F 2203/48 : Variable attenuator
• CPC Class Codes: Y10T 29/49826 : Assembling or joining

Abstract

An optical filter comprising a variable transmittance layer having a first spectrum in a dark state, and a second spectrum in a faded state; and a color balancing layer having a third spectrum; each of the first, second and third spectra comprising a visible portion; the first and third spectra combining to provide a dark state spectrum approximating a dark state target color, and the second and third spectra combining to provide a faded state spectrum approximating a faded state target color. The optical filter may further comprise a light attenuating layer. The optical filter may further comprise part of a laminated glass.

Claims

1. An optical filter comprising:

a. a variable transmittance layer having a first spectrum in a dark state, and a second spectrum in a faded state; and

b. a spectrally uniform color balancing layer having a third spectrum;

each of the first, second and third spectra comprising a visible portion;

the first and third spectra combining to provide a dark state spectrum approximating a dark state target color; and

the second and third spectra combining to provide a faded state spectrum approximating a faded state target colour.

2. The optical filter of claim 1 wherein the color balancing layer is inboard of the variable transmittance layer.

3. The optical filter of claim 1 further comprising c) a light attenuating layer.

4. The optical filter of claim 3 wherein the light attenuating layer is outboard of the variable transmittance layer.

5. The optical filter of claim 1 wherein the variable transmittance layer comprises a switching material transitionable from a faded state to a dark state when exposed to electromagnetic radiation, and from a dark state to a faded state with application of a voltage.

6. The optical filter of claim 1 wherein the electromagnetic radiation is UV light.

7. The optical filter of claim 1 wherein the electromagnetic radiation has a component with a wavelength of 450 nm or less.

8. The optical filter of claim 1 wherein the electromagnetic radiation has a component with a wavelength of between 400 and 450 nm.

9. The optical filter of claim 1 wherein the voltage applied is from about 1.1 to about 2.5 V, or any amount or range therebetween.

10. The optical filter of claim 1 further comprising an infrared (IR)-blocking layer, an ultraviolet (UV) blocking layer, or a UV blocking layer and an IR blocking layer.

11. The optical filter of claim 10 wherein the UV blocking layer blocks light with a wavelength of about 370 nm or less, about 400 nm or less, about 420 nm or less or about 435 nm or less.

12. The optical filter of claim 1 comprising any one or more of:

a. an LT_A in a dark state of less than about 15%;

b. an LT_A in a faded state of greater than about 5%; and

c. a contrast ratio of at least 5.

13. The optical filter of claim 1 comprising a light transmission value of 1% or less in the dark state and 6% or higher in the light state.

14. The optical filter of claim 1 comprising a light transmission value of 5% or less in the dark state and 15% or higher in the light state.

15. The optical filter of claim 1 wherein the target color of the dark state and color of the optical filter in the dark state provide a delta C value of from about 0 to about 20.

16. The optical filter of claim 1 wherein the target color of the dark state and color of the optical filter in the dark state provide a delta E value of from about 0 to about 20.

17. The optical filter of claim 1 wherein the target color of the faded state and color of the optical filter in the faded state provide a delta C value of from about 0 to about 20.

18. The optical filter of claim 1 wherein the target color of the faded state and color of the optical filter in the faded state provide a delta E value of from about 0 to about 20.

19. A device comprising the optical filter of claim 1, wherein the device is a laminated glass, an ophthalmic device, an automotive glazing product or an architectural glazing product;

optionally the automotive glazing product comprises a sunroof.

20. A method of preparing an optical filter approximating a target color, comprising:

a. providing a variable transmittance layer having a first spectrum in a dark state, and a second spectrum in a faded state;

b. selecting a spectrally uniform color balancing layer having a third spectrum; and

c. combining the variable transmittance layer and color balancing layer in a stack approximating the target color in the faded state, the dark state or both the faded state and the dark state.