Color conversion in LCD displays with silica nanoparticles

• US 10,072,153 B2
• Filed: 10/17/2017
• Issued: 09/11/2018
• Est. Priority Date: 11/16/2015
• Status: Expired due to Fees

• Current Assignee: Moleculed Ltd.
• Original Assignee: StoreDot Ltd.
• Inventors: Szwarcman, Daniel, Cohen, Elad, Armon, Mor Shmuel, Kuks, Evgenia Liel (Jeny), Schwarz, Rony, Eisurovich, Elena, Aronov, Daniel, Sella, Eran
• Primary Examiner(s): Salvitti, Michael A
• Application Number:
  US15/785,443
• Publication Number:
  US 20180051174A1
• Time in Patent Office: 329 Days
• CPC Class Codes: C08G 83/001 Macromolecular compounds containing organic and inorganic sequences, e.g. organic polymers grafted onto silica
• CPC Class Codes: C08K 5/29 Compounds containing one or more carbon-to-nitrogen double bonds
• CPC Class Codes: C08K 5/3437 condensed with carbocyclic rings
• CPC Class Codes: C09B 11/24 Phthaleins containing amino groups ; Phthalanes; Fluoranes; Phthalides; Rhodamine dyes; Phthaleins having heterocyclic aryl rings; Lactone or lactame forms of triarylmethane dyes
• CPC Class Codes: C09B 67/0083 Solutions of dyes
• CPC Class Codes: C09B 69/008 Dyes containing a substituent, which contains a silicium atom
• CPC Class Codes: C09B 69/103 containing a diaryl- or triarylmethane dye
• CPC Class Codes: C09K 11/025 non-luminescent particle coatings or suspension media
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: C09K 2211/1007 Non-condensed systems
• CPC Class Codes: C09K 2211/1048 with oxygen
• CPC Class Codes: C09K 2211/1088 containing oxygen as the only heteroatom
• CPC Class Codes: G02F 1/133516 Methods for their manufacture, e.g. printing, electro-deposition or photolithography
• CPC Class Codes: G02F 1/133614 using photoluminescence, e.g. phosphors illuminated by UV or blue light
• CPC Class Codes: G02F 1/133617 Illumination with ultraviolet light; Luminescent elements or materials associated to the cell
• CPC Class Codes: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence
• CPC Class Codes: G02F 2203/055 wavelength filtering
• CPC Class Codes: G03F 7/0007 Filters, e.g. additive colour filters; Components for display devices
• CPC Class Codes: H10K 85/611 Charge transfer complexes
• CPC Class Codes: H10K 85/657 Polycyclic condensed heteroaromatic hydrocarbons

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.

Claims

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 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, F₁TMOS (trimethoxy(3,3,3-trifluoropropyl)silane), F₂TMOS ((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:

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 F₁TMOS.

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

10. The formulation of claim 4, wherein the at least one silane precursor comprises at least one of:

F₂TMOS, 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 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 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, 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:

21. The formulation of claim 19, wherein the RBF compound is a green-fluorescent RBF compound represented by the structure of formula 2-8, 2-9, 2-10, 2-11, 2-12, 2-15 or 2-16: