COLORED FLUIDS FOR ELECTROWETTING, ELECTROFLUIDIC, AND ELECTROPHORETIC TECHNOLOGIES

• US 20120092753A1
• Filed: 03/15/2010
• Published: 04/19/2012
• Est. Priority Date: 03/13/2009
• Status: Active Grant

• Current Assignee: Sun Chemical Corporation
• Original Assignee: Sun Chemical Corporation
• Inventors: Heikenfeld, Jason C., Schwartz, Russell J., Milarcik, April, Clapp, Lisa, Vilner, Stanislav G.
• Granted Patent: US 8,717,663 B2
• Time in Patent Office: Days
• US Class Current: 359/296
• CPC Class Codes: C09B 67/0084 Dispersions of dyes
• CPC Class Codes: C09B 67/009 polymeric dispersing agent
• CPC Class Codes: G02B 26/005 based on electrowetting

Abstract

Colored fluids for electrowetting, electro fluidic, or electrophoretic devices, and the devices themselves, are disclosed. The colored fluid can include a nonaqueous polar solvent having (a) a dynamic viscosity of 0.1 cP to 50 cP at 250 C, (b) a surface tension of 25 dynes/cm to 55 dynes/cm at 250 C, and (c) an electrowetting relative response of 40% to 80%. Such colored fluids further include a colorant selected from a pigment and/or a dye. In another embodiment, the colored fluid can include a non-polar solvent and an organic colorant selected from a pigment and/or a dye. Such colored fluids can be black in color and have a conductivity from 0 pS/cm to 5 pS/cm and a dielectric constant less than 3. The use of the colored fluids offers improvements in reliability, higher levels of chroma in the dispersed state, and the ability to achieve higher contrast ratios in display technologies.

Claims

1. A colored fluid for electrowetting, electrofluidic, or electrophoretic devices comprising:

at least one non-aqueous polar solvent having (a) a dynamic viscosity of 0.1 cP to 50 cP at 25°

C., (b) a surface tension of 25 dynes/cm to 55 dynes/cm at 25°

C., and (c) an electrowetting relative response of 40% to 80%; and

at least one colorant selected from a pigment and/or a dye.

2. The colored fluid of claim 1 wherein the non-aqueous polar solvent is selected from the group consisting of glycols, alcohols, polyols, ethers, esters, ketones, acetals, ketals, lactones, carbonates, lactams, urethanes, ureas, pyrrolidines, pyrrolidones, sulfones, sulfoxides, amides, primary, secondary, tertiary, or quaternary amines, imines, nitriles, carboxylic acids, aldehydes, halogenated, thio, or nitro compounds, and any combinations thereof.

3. The colored fluid of claim 1 wherein the non-aqueous polar solvent is selected from one or more of the following formulas:

4. The colored fluid of claim 1 wherein the non-aqueous polar solvent is selected from the group consisting of 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, diethylene glycol, dipropylene glycol, ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 1,2-cyclohexane carbonate, glycerine carbonate, dimethyl carbonate, diethyl carbonate, acetophenone, pyridine, dimethyl malonate, diacetone alcohol, hydroxypropyl carbamate, beta-hydroxyethyl carbamate, N-methyl formamide, N-methyl acetamide, dimethylsulfoxide, sulfolane, 2-pyrrolidone, N-methyl -2-pyrrolidone, N-cyclohexyl -2-pyrrolidone, acetonyl acetone, cyclohexanone, ethyl acetoacetate, ethyl-L-lactate, pyrrole, N-methyl pyrrole, N-ethyl pyrrole, 4H-pyran-4-one, 1,3-dimethyl-2-imidazolidinone, morpholine, N-methylmorpholine, N-ethylmorpholine, N-formylmorpholine, beta-propiolactone, beta-valerolactone, beta-hexalactone, gamma-butyrolactone, gamma-valerorolactone, gamma-hexalactone, gamma-heptalactone, gamma-octalactone, gamma-nonalactone, gamma-decalactone, delta-valerolactone, delta-hexalactone, delta-heptalactone, delta-octalactone, delta-nonalactone, delta-decalactone, delta-tetradecalactone, delta-octadecolactone, and any combination thereof.

5. The colored fluid of claim 1 wherein the colorant is the pigment.

6. The colored fluid of claim 5 wherein the pigment is a self-dispersed pigment.

7. The colored fluid of claim 6 is devoid of a surfactant, a dispersant, and a resin.

8. The colored fluid of claim 5 wherein the pigment includes a plurality of particles having a mean weight diameter from 10 nm to 5000 nm.

9. The colored fluid of claim 5 further comprising at least one dispersant.

10. The colored fluid of claim 5 wherein the pigment is a self-dispersed pigment, the non-aqueous polar solvent is selected from the group consisting of a lactone, a carbonate, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, diethylene glycol, and dipropylene glycol, and wherein the colored fluid is devoid of a surfactant, a dispersant, and a resin.

11. The colored fluid of claim 1 wherein the colorant is the dye.

12. The colored fluid of claim 11 is devoid of a surfactant, a dispersant, and a resin.

13. The colored fluid of claim 1 further comprising a dispersant, an extender, a synergist, a surfactant, a resin, a polymer, a biocide, or any combination thereof.

14. The colored fluid of claim 1 comprising 60.0 wt % to 99.9 wt % non-aqueous polar solvent and 0.1 wt % to 40.0 wt % colorant, based on a total weight of the colored fluid.

15. The colored fluid of claim 14 wherein the colorant is the pigment and further comprising 0.1 wt % to 200 wt % dispersant based on wt % of the pigment.

16. The colored fluid of claim 1 wherein the non-aqueous polar solvent has a dielectric constant greater than 10.

17. The colored fluid of claim 1 is devoid of a non-polar solvent.

18. The colored fluid of claim 1 having a dynamic viscosity of 0.1 cP to 1000 cP at 25°

C., an interfacial tension of 2 dynes/cm to 55 dynes/cm at 25°

C., and an electrowetting relative response of 10% to 80%.

19. The colored fluid of claim 18 having a conductivity greater than 5 μ

S/cm.

20. The colored fluid of claim 18 having color stability for at least 4 weeks at 25°

C.

21. A colored fluid for electrowetting, electrofluidic, or electrophoretic devices comprising:

at least one non-polar solvent;

at least one organic colorant selected from a pigment and/or a dye; and

wherein the colored fluid is black in color, has a conductivity from 0 pS/cm to 5 pS/cm, and a dielectric constant less than 3.

22. The colored fluid of claim 21 wherein the organic colorant is a black colorant or a combination of two or more organic colorants to provide the black color of the colored fluid.

23. The colored fluid of claim 22 wherein the organic colorant is the black colorant that is selected from the group consisting of C.I. Black Pigment 1, 2, 3, C.I. Vat Black 1, 2, 7, 8, 9, 16, 19, 20, 21, 23, 25, 27, 28, 29, 30, 35, 44, 52, 53, 54, 55, 56, 57, 58, 63, 64, and 65.

24. The colored fluid of claim 21 wherein the organic colorant is an azo, azine, benzimidazolone, azomethine, methine, anthraquinone, arylaminoquinone, phthalocyanine, perinone, diketopyrrolopyrrole, indigo, thio indigo, dioxazine, isoindoline, isoindolinone, iminoisoindoline, iminoisoindolinone, quinacridone, flavanthrone, indanthrone, indanthren, indole-thianaphthene, anthanthrone, anthrapyrimidine, perylene, quinophthalone, violanthrene, isoviolanthrone, violanthrene, pyranthrone, or any combination thereof to provide the black color of the colored fluid.

25. The colored fluid of claim 21 wherein the non-polar solvent is a linear or branched alkane, an arylalkane, a fatty acid, an alcohol, an aromatic or alicyclic hydrocarbon, a heterocyclic compound, a halogenated hydrocarbon, an polymer or oligomer based on silicon or germanium, a cyclic siloxane, or a combination thereof.

26. The colored fluid of claim 21 is devoid of a polar solvent and/or resin.

27. A pixel for a display, the pixel comprising:

a reservoir;

a colored fluid in the reservoir, the colored fluid including at least one non-polar solvent and at least one organic colorant selected from a pigment and/or a dye, the colored fluid being black in color, having a conductivity from 0 pS/cm to 5 pS/cm, and having a dielectric constant less than 3;

a plurality of charged particles suspended within the colored fluid; and

a plurality of electrodes configured to apply a potential difference effective to cause the charged particles to move within the color fluid relative to at least one of the electrodes.

28. A pixel for a display, the pixel comprising:

a reservoir;

a colored fluid in the reservoir, the colored fluid including at least one non-aqueous polar solvent having (a) a dynamic viscosity of 0.1 cP to 50 cP at 25°

C., (b) a surface tension of 25 dynes/cm to 55 dynes/cm at 25°

C., and (c) an electrowetting relative response of 40% to 80%, and at least one colorant selected from a pigment and/or a dye; and

a plurality of electrodes configured to apply a potential difference effective to move the colored fluid relative to at least one of the electrodes.

29. A pixel for a display, the pixel comprising:

a reservoir;

a colored fluid in the reservoir, the colored fluid including at least one non-polar solvent and at least one organic colorant selected from a pigment and/or a dye, the colored fluid being black in color, having a conductivity from 0 pS/cm to 5 pS/cm, and having a dielectric constant less than 3;

a polar fluid in the reservoir, the polar fluid occupying a volume within the reservoir not occupied by the colored fluid; and

a plurality of electrodes configured to apply a potential difference effective to move the polar fluid relative to at least one of the electrodes such that the movement of the polar fluid changes a shape of the colored fluid.