Color conversion in LCD displays

Patent metadata

Field	Value
Publication number	US-9868859-B2
Application number	US-201615353015-A
Country	US
Kind code	B2
Filing date	Nov 16, 2016
Priority date	Nov 16, 2015
Publication date	Jan 16, 2018
Grant date	Jan 16, 2018

Abstract

Color conversion films for a LCD (liquid crystal display) having RGB (red, green, blue) color filters, as well as such displays, formulations, precursors and methods are provided, which improve display performances with respect to color gamut, energy efficiency, materials and costs. The color conversion films absorb backlight illumination and convert the energy to green and/or red emission at high efficiency, specified wavelength ranges and narrow emission peaks. For example, rhodamine-based fluorescent compounds are used in matrices produced by sol gel processes and/or UV (ultraviolet) curing processes which are configured to stabilize the compounds and extend their lifetime—to provide the required emission specifications of the color conversion films. Film integration and display configurations further enhance the display performance with color conversion films utilizing various color conversion elements.

First claim

The invention claimed is:

1. A hybrid sol-gel precursor formulation comprising:
an ESOR (epoxy silica ormosil) solution comprising TEOS (tetraethyl orthosilicate), at least one silane precursor other than TEOS, and GLYMO ((3-Glycidyloxypropyl) trimethoxysilane);
a DURS (diurethane siloxane) nanoparticles powder comprising isocyanate-functionalized silica nanoparticles and ethylene glycol, wherein the silica nanoparticles are maintained as nanoparticles in the formulation; and
a transition metal alkoxide matrix solution.

2. The sol-gel precursor formulation of claim 1 , wherein ratios (wt/vol/vol (mg/ml/ml)) of the DURS/the ESOR/and the transition metal alkoxide matrix solution are 15-25/1-3/1.

3. The sol-gel precursor formulation of claim 1 , wherein the at least one silane precursor comprises at least one of: PhTMOS (trimethoxyphenylsilane), a TMOS (trimethoxysilane) with fluorine substituents, F 1 TMOS (trimethoxy(3,3,3-trifluoropropyl)silane), F 2 TMOS ((tridecafluoro-1,1,2,2-tetrahydrooctyl)trimethoxysilane), 1,2-bis(triethoxysilyl)ethane, trimethoxy(propyl)silane, octadecyltrimethoxysilane, fluorotriethoxysilane, and ammonium(propyl)trimethoxysilane.

4. A formulation comprising the hybrid sol-gel precursor formulation of claim 1 and at least one rhodamine-based fluorescent (RBF) compound.

5. The formulation of claim 4 , wherein the RBF compound is a red-fluorescent RBF compound and the at least one silane precursor comprises PhTMOS.

6. The formulation of claim 5 , wherein the red-fluorescent RBF compound is defined by
Formula 1:

wherein
R 1 is COOR, NO 2 , COR, COSR, CO(N-heterocycle), CON(R) 2 , or CN;
R 2 each is independently selected from H, halide, N(R) 2 , COR, CN, CON(R) 2 , CO(N-heterocycle), NCO, NCS, OR, SR, SO 3 H, SO 3 M and COOR;
R 3 each is independently selected from H, halide, N(R) 2 , COR, CN, CON(R) 2 , CO(N-heterocycle), NCO, NCS, OR, SR, SO 3 H, SO 3 M and COOR;
R 4 -R 16 and R 4′ -R 16′ are each independently selected from H, CF 3 , alkyl, haloalkyl, cycloalkyl, heterocycloalkyl, alkenyl, alkynyl, aryl, benzyl, halide, NO 2 , OR, N(R) 2 , COR, CN, CON(R) 2 , CO(N-Heterocycle) and COOR;
R is H, alkyl, cycloalkyl, heterocycloalkyl, alkenyl, alkynyl, aryl, benzyl, —(CH 2 CH 2 O) r CH 2 CH 2 OH, —(CH 2 ) p OC(O)NH(CH 2 ) q Si(Oalkyl) 3 , —(CH 2 ) p OC(O)CH═CH 2 or —(CH 2 ) p Si(Oalkyl) 3 ;
n and m are each independently an integer between 1-4;
p and q are each independently an integer between 1-6;
r is an integer between 0-10;
M is a monovalent cation; and
X is an anion.

7. The formulation of claim 4 , wherein the RBF is a red-fluorescent RBF compound and the at least one silane precursor comprises a TMOS with fluorine substituents.

8. The formulation of claim 4 , wherein the RBF is a green-fluorescent RBF compound and the at least one silane precursor comprises F 1 TMOS.

9. The formulation of claim 8 , wherein the green-fluorescent RBF compound is defined by
Formula 4:

wherein:
R 1 each is independently H, Q 1 , OQ 1 , CF 3 , C(O)OQ 1 , C(O)NQ 1 Q 2 , NHC(O)Q 1 , C(O)Q 1 , NQ 1 Q 2 , NO 2 , CN, SQ 1 , —NQ 1 Q 2 CONQ 3 Q 4 , NCO, NCS, —OC(O)OQ 1 , SO 3 —, SO 3 Q 1 , or halide;
n is an integer between 1-5;
R 3 , R 3′ , R 6 and R 6′ are each independently selected from H, CF 3 , alkyl, alkenyl, alkynyl, haloalkyl, heterocycloalkyl, cycloalkyl, aryl and benzyl;
R 2 , R 2′ , R 4 , R4′, R 5 and R 5′ are each independently selected from H, Q 1 , OQ 1 , CF 3 , NQ 1 Q 2 , NO 2 , CN, SO 3 − , SO 3 Q 1 and halide;
Q 1 and Q 2 are each independently selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, azide, haloalkyl, heterocycloalkyl, cycloalkyl, aryl, benzyl, —(CH 2 ) p OC(O)NH(CH 2 ) q Si(Oalkyl) 3 , —(CH 2 ) p OC(O)CH═CH 2 , —(CH 2 ) p Si(Oalkyl) 3 , —OC(O)N(H)Q 4 , —OC(S)N(H)Q 4 , —N(H)C(O)N(Q 3 ) 2 and —N(H)C(S)N(Q 3 ) 2 ;
Q 3 and Q 4 are each independently selected from H, alkyl, haloalkyl, heterocycloalkyl, cycloalkyl, aryl and benzyl;
X is an anion.

10. The formulation of claim 4 , wherein the at least one silane precursor comprises at least one of: F 2 TMOS, 1,2-bis(triethoxysilyl)ethane, trimethoxy(propyl)silane, octadecyltrimethoxysilane, fluorotriethoxysilane, and ammonium(propyl)trimethoxysilane.

11. A color conversion film for a LCD (liquid crystal display) having RGB (red, green, blue) color filters, the color conversion film prepared from the formulation of claim 4 by a sol gel process, wherein the RBF compound is selected to absorb illumination from a backlight source of the LCD and have at least one of a R emission peak and a G emission peak.

12. The LCD comprising the color conversion film of claim 11 .

13. The LCD of claim 12 , wherein the color conversion film is in the LCD panel.

14. A method comprising:
preparing a hybrid sol-gel precursor formulation from:
an ESOR (epoxy silica ormosil) solution comprising TEOS (tetraethyl orthosilicate), at least one silane precursor other than TEOS, and GLYMO ((3-Glycidyloxypropyl) trimethoxysilane);
a DURS (diurethane siloxane) nanoparticles powder comprising isocyanate-functionalized silica nanoparticles and ethylene glycol, wherein the silica nanoparticles are maintained as nanoparticles in the formulation; and
a transition metal alkoxide matrix solution, and

mixing the hybrid sol-gel precursor with at least one RBF compound; and
spreading the mixture and drying the spread mixture to form a film.

15. The method of claim 14 , further comprising evaporating alcohols from the mixture prior to the spreading.

16. The method of claim 14 , wherein the spreading is carried out by bar coating.

17. The method of claim 14 , wherein the drying is carried out by at least one of convective heating, evaporating and infrared radiation.

18. The method of claim 14 , further comprising associating the film with any of:
a diffuser, a prism film and a polarizer film in a display backlight unit.

19. A formulation comprising:
a hybrid sol-gel precursor formulation comprising:
an ESOR (epoxy silica ormosil) solution comprising TEOS (tetraethyl orthosilicate), at least one silane precursor other than TEOS, and GLYMO ((3-Glycidyloxypropyl) trimethoxysilane);
a DURS (diurethane siloxane) nanoparticles powder comprising isocyanate-functionalized silica nanoparticles and ethylene glycol, wherein the silica nanoparticles are maintained as nanoparticles in the formulation; and
a transition metal alkoxide matrix solution;

and a at least one rhodamine-based fluorescent (RBF) compound;
wherein the at least one silane precursor, isocyanate-functionalized silica and transition metal alkoxide matrix are selected according to the RBF compound and may be tuned to receive a desired emission spectra.

20. The formulation of claim 19 , wherein the RBF compound is a red-fluorescent RBF compound represented by the structure of formula 1-1, 1-2, 1-3, 1-4, 1-5, 1-6, 1-7, 1-8, 1-9, 1-10, or 1-11:

Assignees

• Storedot Ltd

Inventors

• Szwarcman Daniel
• Cohen Elad
• ARMON Mor Shmuel
• KUKS Evgenia Liel (Jeny)
• Schwarz Rony
• Eisurovich Elena
• Aronov Daniel
• Sella Eran

Classifications

• C08K5/3437

  condensed with carbocyclic rings · CPC title

• G02F1/133617

  Illumination with ultraviolet light; Luminescent elements or materials associated to the cell · CPC title

• C09K2211/1088

  containing oxygen as the only heteroatom · CPC title

• G02F1/133516

  Methods for their manufacture, e.g. printing, electro-deposition or photolithography · CPC title

• C09B11/24

  Phthaleins containing amino groups {; Phthalanes; Fluoranes; Phthalides; Rhodamine dyes; Phthaleins having heterocyclic aryl rings; Lactone or lactame forms of triarylmethane dyes} · CPC title