Color conversion films produced by UV curing processes

• US 10,473,979 B2
• Filed: 11/16/2016
• Issued: 11/12/2019
• Est. Priority Date: 11/16/2015
• Status: Active Grant

• 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): Kosack, Joseph R
• Application Number:
  US15/353,256
• Publication Number:
  US 20170139277A1
• Time in Patent Office: 1,091 Days
• 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 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: C09D 4/00 Coating compositions, e.g. paints, varnishes or lacquers, based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; Coating compositions, based on monomers of macromolecular compounds of groups C09D183/00 - C09D183/16
• CPC Class Codes: C09D 5/22 Luminous paints luminescent compositions C09K11/00
• 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: G03F 7/027 Non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds, e.g. ethylenic compounds G03F7/075 takes precedence
• CPC Class Codes: G03F 7/031 Organic compounds not covered by group G03F7/029
• CPC Class Codes: G03F 7/105 having substances, e.g. indicators, for forming visible images
• 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 color conversion film for a LCD (liquid crystal display) having RGB (red, green, blue) filters, the color conversion film prepared by UV (ultraviolet) curing from a formulation comprising:

65-70% monomers,

25-30% oligomers, and

5% photointiator, and

0.005-0.05% at least one rhodamine-based fluorescent (RBF) compound configured to absorb illumination from a LCD backlight source and have at least one of a R emission peak and a G emission peak;

wherein the at least one RBF compound is defined, respectively, by at least one of Formula 1 and Formula 4;

2. The color conversion film of claim 1, wherein the monomers consist of at least one of:

dipropylene glycol diacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol hexaacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated (3) glyceryl acrylate and trimethylolpropane triacrylate.

3. The color conversion film of claim 1, wherein the oligomers consist of at least one of:

polyester acrylate, modified polyester resin diluted with dipropyleneglycol diacrylate and aliphatic urethane hexaacrylate.

4. The color conversion film of claim 1, wherein the photointiator consists of at least one of:

alpha-hydroxy-cyclohexyl-phenyl-ketone and alpha-hydroxy ketone.

5. The color conversion film of claim 1, wherein the backlight source of the LCD provides blue illumination and the at least one RBF compound comprises at least one red-fluorescent RBF compound defined by Formula 1 and at least one green-fluorescent RBF compound defined by Formula 4.

6. A LCD comprising at least one color conversion film of claim 1 having both R and G emission peaks, a backlight unit comprising the backlight source and a LCD panel having the RGB color filters, wherein the at least one color conversion film is positioned in the LCD panel and is patterned with respect to a patterning of the RGB color filters to yield a spatial correspondence between film regions with R and G emission peaks and respective R and G color filter.

7. A LCD comprising at least one color conversion film of claim 1 having both R and G emission peaks, a backlight unit comprising the backlight source and a LCD panel having the RGB color filters, wherein an intensity of the R and G emission peaks of the at least one color conversion film are adjusted to fine tune a white point of the LCD to be at a center of an expected line of deterioration of the intensity within given LCD specifications.