SPD films with darker off-state transmittances and lighter on-state transmittances

• US 8,922,872 B2
• Filed: 02/07/2013
• Issued: 12/30/2014
• Est. Priority Date: 02/10/2012
• Status: Active Grant

• Current Assignee: Research Frontiers Incorporated
• Original Assignee: Research Frontiers Incorporated
• Inventors: Chen, Xiao-Ping, Slovak, Steven M., Van Voorhees, Seth
• Primary Examiner(s): TRA, TUYEN Q
• Application Number:
  US13/761,577
• Publication Number:
  US 20130208342A1
• Time in Patent Office: 691 Days
• Field of Search: 359/296, 359/253, 359/241, 345/107, 252582-584, 252/588
• US Class Current: 359/296
• CPC Class Codes: G02F 1/172 based on a suspension of orientable dipolar particles, e.g. suspended particles displays

Abstract

A light valve film forming a light-modulating element of a light valve, the film comprised of a cross-linked polymer matrix with a plurality of droplets of a liquid light valve suspension distributed therein. The film has a phase ratio: % particle number value calculated by the formula:

$\frac{\mathrm{Matrix}/\mathrm{capsule}\mathrm{ratio}}{\%\mathrm{particles}\mathrm{in}\mathrm{the}\mathrm{capsule}}=\mathrm{Phase}\mathrm{ratio}\text{:}\%\mathrm{particle}\mathrm{number}$
In one embodiment the light valve film has a relatively low visible transmittance in the unpowered Off state such that the film has a % T of <0.05 and a ΔT of >42%. In another embodiment the light valve film has a relatively high visible transmittance in the On state such that the film has a % T of >70% and a ΔT of >57%.

Claims

1. A light valve film forming a light modulating element of a light valve, said film comprised of a cross-linked matrix polymer with a plurality of droplets of a liquid light valve suspension distributed therein, said film having a phase ratio:

% particle number value >

0.157 and <

0.220, wherein the phase ratio;

% particle number value is calculated using the following formula

2. The light valve film of claim 1, further comprising, applied upon said film, at least one layer selected from among a film, a coating and a sheet, wherein the at least one layer provides to said film at least one selected from the group consisting of scratch resistance, protection from ultraviolet radiation, reflection from of infrared energy, electrical conductivity for transmitting an applied electric or magnetic field to the light valve field, insulation protection from short circuits, color tinting and acoustic control.

3. An electro-optical device for controlling the transmission of radiation, said device having two opposed sides and comprising, from one side to the other:

(a) a first sheet of polyethylene terephthalate (PET) plastic;

(b) a first thin, transparent electrically conductive coating that acts, or is capable of acting as an electrode, on the first sheet of PET;

(c) a first light valve film according to claim 1;

(d) a second thin, transparent electrically conductive coating acting or capable of acting as an electrode, said second coating applied upon an outer surface of,

(e) a second sheet of polyethylene terephthalate plastic;

(f) a third thin, transparent electrically conductive coating acting or capable of acting as an electrode, said third coating applied upon an inner surface of said second sheet of polyethylene terephthalate plastic,

(g) a second light valve film according to claim 1;

(h) a fourth thin, transparent electrically conductive coating acting or capable of acting as an electrode, said fourth coating applied upon an inner surface of,

(i) a third sheet of polyethylene terephthalate (PET) plastic.

4. An electro-optical device for controlling the transmission of radiation, said device having two opposed sides and comprising, from one side to the other:

(a) a first sheet of polyethylene terephthalate (PET) plastic;

(b) a first thin, transparent electrically conductive coating that acts, or is capable of acting as an electrode, on the first sheet of PET;

(c) a first light valve film according to claim 1;

(d) a second thin, transparent electrically conductive coating acting or capable of acting as an electrode, said second coating applied upon an outer surface of,

(e) a second sheet of polyethylene terephthalate plastic;

(f) a third thin, transparent electrically conductive coating acting or capable of acting as an electrode, said third coating applied upon an inner surface of said second sheet of polyethylene terephthalate plastic,

(g) a second light valve film comprised of a cross-linked matrix polymer with a plurality of droplets of a liquid light valve suspension distributed therein, said film having a phase ratio;

% particle number value >

0.802 and <

1.197, wherein the phase ratio;

% particle number value is calculated using the following formula

Matrix/capsule ratio=Phase ratio;

% particle number % particles in the capsule

and wherein the light valve film has a relatively high visible transmittance in the On state such that the film has a % T of >

70% and a Δ

T of >

57%;

(h) a fourth thin, transparent electrically conductive coating acting or capable of acting as an electrode, said fourth coating applied upon an inner surface of,

(i) a third sheet of polyethylene terephthalate (PET) plastic.

5. An electro-optical device for controlling the transmission of radiation, said device having two opposed sides and comprising, from one side to the other:

(a) a first sheet of polyethylene terephthalate (PET) plastic;

(b) a first thin, transparent electrically conductive coating that acts, or is capable of acting as an electrode, on the first sheet of PET;

(c) a first light valve film comprised of a cross-linked matrix polymer with a plurality of droplets of a liquid light valve suspension distributed therein, said film having a phase ratio;

% particle number value >

0.802 and <

1.197, wherein the phase ratio;

% particle number value is calculated using the following formula

Matrix/capsule ratio=Phase ratio;

% particle number % particles in the capsule

and wherein the light valve film has a relatively high visible transmittance in the On state such that the film has a % T of >

70% and a Δ

T of >

57%;

(d) a second thin, transparent electrically conductive coating acting or capable of acting as an electrode, said second coating applied upon an outer surface of,

(e) a second sheet of polyethylene terephthalate plastic;

(f) a third thin, transparent electrically conductive coating acting or capable of acting as an electrode, said third coating applied upon an inner surface of said second sheet of polyethylene terephthalate plastic,

(g) a second light valve according to claim 1;

(h) a fourth thin, transparent electrically conductive coating acting or capable of acting as an electrode, said fourth coating applied upon an inner surface of,

(i) a third sheet of polyethylene terephthalate (PET) plastic.

6. A light valve film forming a light modulating element of a light valve, said film comprised of a cross-linked matrix polymer with a plurality of droplets of a liquid light valve suspension distributed therein, said film having a phase ratio:

% particle number value >

0.802 and <

1.197, wherein the phase ratio;

% particle number value is calculated using the following formula

7. The light valve film of claim 6, further comprising, applied upon said film, at least one layer selected from among a film, a coating and a sheet, wherein the at least one layer provides to said film at least one selected from the group consisting of scratch resistance, protection from ultraviolet radiation, reflection of infrared energy, electrical conductivity for transmitting an applied electric or magnetic field, insulation protection from short circuits, color tinting and acoustic control.

8. An electro-optical device for controlling the transmission of radiation, said device having two opposed sides and comprising, from one side to the other:

(a) a first sheet of polyethylene terephthalate (PET) plastic;

(b) a first thin, transparent electrically conductive coating that acts, or is capable of acting as an electrode, on the first sheet of PET;

(c) a first light valve film according to claim 6;

(d) a second thin, transparent electrically conductive coating acting or capable of acting as an electrode, said second coating applied upon an outer surface of,

(e) a second sheet of polyethylene terephthalate plastic;

(f) a third thin, transparent electrically conductive coating acting or capable of acting as an electrode, said third coating applied upon an inner surface of said second sheet of polyethylene terephthalate plastic,

(g) a second light valve film according to claim 6;

(h) a fourth thin, transparent electrically conductive coating acting or capable of acting as an electrode, said fourth coating applied upon an inner surface of,

(i) a third sheet of polyethylene terephthalate (PET) plastic.