Optical devices containing multilayer optical products with infrared absorbing adhesive layers

Abstract

An optical device includes a visible light source, a visible light detector, and a multilayer film article located in a path between the visible light source and the visible light detector. The multilayer film article includes an optical film layer and an optically transparent adhesive layer. The optically transparent adhesive layer includes a polymer adhesive matrix and at least one infrared light absorbing material that absorbs light in the range of 680 nm to 1100 nm. The infrared light absorbing material is an organic dye.

Description

Technical Field

[0001] This disclosure relates to multilayer articles containing an optically transparent adhesive layer containing an infrared light-absorbing material, and to devices containing such multilayer optical articles. Background Technology

[0002] A wide variety of optical and electronic products have multiple layers of films and substrates. These multiple layers are typically bonded together with adhesive layers. Optical products have a wide range of applications, such as sensing products and display products. Summary of the Invention

[0003] This document discloses multilayer optical articles and optical devices incorporating such multilayer articles. In some embodiments, the optical device includes a fingerprint sensor. In some embodiments, an optical device (300) configured to sense the presence of a finger (10) includes: an emitting display (20) configured to emit a visible image (21) in a visible wavelength range extending from about 420 nm to about 680 nm; a visible light source (30, 31, 32) configured to emit light (30a, 31a, 32a) having a first wavelength (64) in the visible wavelength range; a visible light detector (40) configured to detect emitted light after it has been reflected by the finger (30b, 31b, 32b); and a multilayer film article (50) situated in the path between the visible light source and the visible light detector. The multilayer film article includes a first optical film layer (60) comprising a plurality of polymer layers (61, 62) totaling at least 10 layers, each polymer layer having an average thickness of less than about 400 nm, such that for incident light (70) incident on the first optical film layer and for at least one polarization state (x-axis), the plurality of polymer layers reflect at least 70% of incident light having a first wavelength for each of a first incident angle (θ) less than about 5 degrees and a second incident angle greater than about 45 degrees, reflect at least 70% of incident light having a second wavelength (65) in the infrared wavelength range extending from about 680 nm to about 1100 nm for the first incident angle, and transmit at least 40% of incident light having a second wavelength for the second incident light. The multilayer film also has an optically transparent adhesive layer (80) disposed on at least a portion of the first optical film layer, the optically transparent adhesive layer comprising a polymer adhesive matrix and at least one infrared light absorbing material that absorbs light having a second wavelength.

[0004] Multilayer film articles are also disclosed. In some embodiments, the multilayer film article includes a first optical film layer having a first main surface and a second main surface, and an optically transparent adhesive layer having a first main surface and a second main surface, wherein the first main surface of the optically transparent adhesive layer is disposed on at least a portion of the second main surface of the first optical film layer. The optically transparent adhesive layer includes a polymer adhesive matrix and at least one infrared light absorbing material that absorbs light in the range of 680 nm to 1100 nm.

[0005] In some embodiments, a multilayer optical article includes a first optical film layer having a first main surface and a second main surface, and an optically transparent adhesive layer having a first main surface and a second main surface, wherein the first main surface of the optically transparent adhesive layer is disposed on at least a portion of the second main surface of the first optical film layer. The optically transparent adhesive layer comprises a polymer adhesive matrix and at least one infrared light absorbing material, which includes diimonium dyes, anthraquinone dyes, aminium dyes, cyanine dyes, croconium dyes, squarylium dyes, rylene dyes, chamomilene dyes, polymethyne dyes, naphthoquinone dyes, pyridinium dyes, phthalocyanine dyes, naphthalocyanine dyes, naphthlolactam dyes, azo dyes, indigo dyes, pyrene dyes, terrylene dyes, dioxadine dyes, quinacridone dyes, isodorynone dyes, quinoline phthalone dyes, pyrrole dyes, or thioindigo dyes. Attached Figure Description

[0006] This application can be more fully understood by referring to the following detailed description of various embodiments of this disclosure in conjunction with the accompanying drawings.

[0007] Figure 1 This is a graph showing the transmittance % of the coatings from DCC1 to DCC4.

[0008] Figure 2 This is a graph showing the transmittance % of adhesive example 1.

[0009] Figure 3 This is a graph showing the transmittance % of the adhesive in Example 2.

[0010] Figure 4 This is a graph showing the transmittance % of the adhesive in Example 3.

[0011] Figure 5 This is a graph showing the transmittance % of adhesive example 4.

[0012] Figure 6 This is a graph showing the transmittance % of adhesive example 5.

[0013] Figure 7 This is a graph showing the transmittance % of the adhesive in Example 6.

[0014] Figure 8 This is a cross-sectional view of the device disclosed herein.

[0015] Figure 9 This is a cross-sectional view of the multilayer film product disclosed herein.

[0016] Figure 10 This is a graph comparing the transmittance % of multilayer optical products at different incident angles.

[0017] In the following description of the illustrated embodiments, reference is made to the accompanying drawings, in which various embodiments in which this disclosure may be practiced are shown by way of example. It should be understood that embodiments may be utilized and structural changes may be made without departing from the scope of this disclosure. The drawings are not necessarily drawn to scale. Similar numbers used in the drawings refer to similar parts. However, it should be understood that the use of numbers to refer to parts in a given drawing is not intended to limit parts labeled with the same numbers in another drawing. Detailed Implementation

[0018] Many optical products have multiple layers. These layers are typically bonded together with adhesive layers. These adhesive layers have a variety of desired or required properties. Achieving some of these properties is a very complex process. Adhesive layers are designed to bond two films or substrates together, but they often require additional properties. Many of these properties are difficult to achieve because imparting new properties to the adhesive layer cannot be done by sacrificing adhesive properties.

[0019] A range of optically transparent adhesives have been developed for use in optical articles. These adhesives possess both adhesive properties and optical transparency. This combination of properties makes them well-suited for a wide range of applications. In some applications, additional properties are desired in optically transparent adhesives. However, these new properties cannot be achieved by sacrificing either adhesive or optical properties.

[0020] Optical sensing devices, such as fingerprint sensors, are found in optical articles that utilize multilayer optical films or substrates. These articles typically include multilayer optical films that reflect incident light (including IR (infrared) light). When the incident light is perpendicular to the optical film, the multilayer optical film is effective in reflecting the incident light. However, when the incident light is “off-axis,” meaning the light is not perpendicular to the optical film, at least 40% of IR light of at least some wavelengths is allowed to pass through, although it is still partially reflected by the multilayer optical film. IR light can be problematic because it can interfere with the signal. In use, off-axis IR light is a problem because it can penetrate the finger or bypass the finger at an off-axis angle. Figure 10 A graph illustrating the transmittance % of a multilayer article at normal incidence and a 60° incident angle is shown. The graph clearly shows that at a 60° incident angle, a significant amount of IR light is transmitted, which is not transmitted at the normal incident angle. Therefore, it is desirable to add an IR-absorbing layer to the sensor to absorb off-axis IR light not reflected by the multilayer optical film. However, adding another layer to an already complex layer combination is not advisable. Therefore, it is desirable to modify the existing layers to achieve the desired IR light absorption. Since an adhesive layer is present in the multilayer article, it is desirable to modify the optically clear adhesive (OCA) with an IR absorber. However, this modification will not adversely affect the optical transparency of the layer.

[0021] This invention discloses an adhesive layer that maintains a high level of visible light transmittance and additionally absorbs IR light. These adhesive layers include optically clear adhesives (OCAs) with IR absorbers.

[0022] Multilayer optical products can be used in optical devices, such as devices including light sources and optical detectors, wherein the multilayer product is located in the optical path between the light source and the optical detector.

[0023] Unless otherwise specified, all figures used in the specification and claims to express structural dimensions, quantities, and physical properties should in all cases be understood to be modified by the term "about". Therefore, unless stated to the contrary, the numerical parameters listed in the foregoing specification and appended claims are approximations, which may vary according to the desired properties sought by a person skilled in the art using the teachings disclosed herein. Numerical ranges expressed in terms of endpoints include all numbers contained within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) and any range within that range.

[0024] Unless otherwise expressly stated, as used in this specification and the appended claims, the singular forms “a,” “an,” and “described” cover embodiments having multiple referents. For example, the reference to “a layer” covers embodiments having one layer, two layers, or more layers. Unless otherwise expressly stated, as used in this specification and the appended claims, the term “or” is generally used in a meaning that includes “and / or.”

[0025] As used herein, the term "adhesive" refers to a polymer composition that can be used to adhere two adhesives together. An example of an adhesive is a pressure-sensitive adhesive.

[0026] Those skilled in the art are well aware that pressure-sensitive adhesive compositions possess properties including (1) strong and durable tack, (2) adhesion upon finger pressure, (3) sufficient ability to hold onto the adhesive, and (4) sufficient cohesive strength for clean removal from the adhesive. Materials found to be well-suited for use as pressure-sensitive adhesives are polymers designed and formulated to exhibit the desired viscoelastic properties, thereby achieving a desired balance between tack, peel adhesion, and shear retention. Achieving this proper balance of properties is not a simple matter.

[0027] The term "(meth)acrylate" refers to the monomeric acrylate or methacrylate of an alcohol. Acrylates and methacrylate monomers or oligomers are collectively referred to herein as "(meth)acrylate". Materials described as "(meth)acrylate functional" are materials containing one or more (meth)acrylate groups. Polymers described as "(meth)acrylate-based" contain a majority weight of at least one (meth)acrylate monomer and may contain other olefinically unsaturated comonomers.

[0028] The terms "room temperature" and "ambient temperature" are used interchangeably, referring to temperatures in the range of 20°C to 25°C.

[0029] The terms "Tg" and "glass transition temperature" are used interchangeably. If measured, unless otherwise specified, the Tg value is determined by differential scanning calorimetry (DSC) at a scan rate of 10 °C / min. Typically, the Tg value of the copolymer is not measured; instead, it is calculated using the well-known Fox formula, using the monomer Tg values ​​provided by the monomer supplier, as understood by those skilled in the art.

[0030] As used herein, the term "adjacent" in the context of two floors means that the two floors are adjacent to each other and there is no intervening opening space between them. They may be in direct contact with each other (e.g., stacked together) or there may be an intervening floor.

[0031] As used herein, the terms “polymer” and “macromolecule” are consistent with their common usage in chemistry. Polymers and macromolecules are composed of many repeating subunits. As used herein, the term “macromolecule” is used to describe a group attached to a monomer that has multiple repeating units. The term “polymer” is used to describe the material obtained by a polymerization reaction.

[0032] The term "alkyl" refers to a monovalent group that is an alkane group, where the alkane is a saturated hydrocarbon. Alkyl groups can be straight-chain, branched, cyclic, or combinations thereof, and typically have 1 to 20 carbon atoms. In some embodiments, the alkyl group contains 1 to 18, 1 to 12, 1 to 10, 1 to 8, 1 to 6, or 1 to 4 carbon atoms. Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, and ethylhexyl ester.

[0033] The term "alkanediol" refers to a divalent group that is a group of an alkane. Alkanediols can be straight-chain, branched, cyclic, or a combination thereof. Alkanediols typically have 1 to 20 carbon atoms. In some embodiments, alkanediols contain 1 to 18, 1 to 12, 1 to 10, 1 to 8, 1 to 6, or 1 to 4 carbon atoms. The group center of the alkanediol can be on the same carbon atom (i.e., an alkylidene group) or on different carbon atoms.

[0034] The term "heteroalkylene" refers to a divalent group comprising at least two alkylene groups linked by a thio, oxygen, or -NR- group, wherein R is an alkyl group. Heteroalkylene groups can be straight-chain, branched, cyclic, substituted with alkyl groups, or combinations thereof. Some heteroalkylene compounds are polyoxyalkylenes, wherein the heteroatom is an oxygen atom, such as, for example...

[0035] -CH2CH2(OCH2CH2) n OCH2CH2-.

[0036] The terms “radical polymerizable” and “olefinic unsaturated” are used interchangeably and refer to reactive groups containing carbon-carbon double bonds capable of polymerization via a radical polymerization mechanism.

[0037] Unless otherwise specified, the terms "optically transparent" and "visible light transmittance" are used interchangeably and refer to articles, films, or adhesives having high transmittance over at least a portion of the visible light spectrum (about 400 nm to about 700 nm). Typically, optically transparent articles have a visible light transmittance of at least 80% of the incident light not reflected from the surface and a haze of less than 10%.

[0038] Unless otherwise specified, "optically transparent" means an adhesive or article that has high transmittance and exhibits low haze (typically less than about 5%, or even less than about 2%) over at least a portion of the visible light spectrum (about 400 nm to about 700 nm). In some embodiments, the optically transparent article exhibits haze of less than 1% or even 0.5% at a thickness of 50 micrometers. Typically, the optically transparent article has at least 95%, and often higher, such as 97%, 98%, or even 99% or higher, of visible light transmittance.

[0039] As used herein, the terms “infrared light absorption,” “IR light absorption,” or “IR absorption” are used interchangeably and refer to materials that absorb light in at least some portion of the infrared spectrum from about 680 nm to 1100 nm.

[0040] This document discloses multilayer film articles. In some embodiments, the multilayer film article includes a first optical film layer having a first main surface and a second main surface, and an optically transparent adhesive layer having a first main surface and a second main surface, wherein the first main surface of the optically transparent adhesive layer is disposed on at least a portion of the second main surface of the first optical film layer. The optically transparent adhesive layer includes a polymer adhesive matrix and at least one infrared light absorbing material that absorbs light in the range of 680 nm to 1100 nm. These optically transparent adhesive layers containing infrared light absorbing materials can be described in two different ways: by light absorption characteristics and by compositional characteristics. In some embodiments, the ratio of the minimum transmittance of the at least one infrared light absorbing material in the range of 680 nm to 1100 nm to the transmittance at 500 nm is 0 to 0.5. In some embodiments, this ratio is less than 0.4, less than 0.3, less than 0.2, less than 0.1, or even less than 0.05. Therefore, the optically transparent adhesive layer transmits visible light and absorbs IR light. In other embodiments, the optically transparent adhesive layer is described by the chemical description of the infrared absorbing material (typically an infrared absorbing dye). The following is a description of suitable infrared absorbing dyes.

[0041] There are many suitable optically transparent pressure-sensitive adhesive compositions. The pressure-sensitive adhesive component can be a single pressure-sensitive adhesive, or it can be a combination of two or more pressure-sensitive adhesives.

[0042] Suitable pressure-sensitive adhesives include, for example, those based on natural rubber, synthetic rubber, styrene block copolymers, polyethylene ether, poly(meth)acrylate (including both acrylate and methacrylate), polyolefins, or silicone.

[0043] Particularly suitable are pressure-sensitive adhesives based on (meth)acrylates. In some embodiments, the (meth)acrylate-based pressure-sensitive adhesive is a radiation-curable pressure-sensitive adhesive as described below. In other embodiments, the (meth)acrylate-based pressure-sensitive adhesive is not radiation-curable.

[0044] Optically transparent pressure-sensitive adhesives based on (meth)acrylates can be (meth)acrylate copolymers comprising a combination of one or more alkyl (meth)acrylate monomers with other alkyl-bonded unsaturated monomers. Available alkyl (meth)acrylates (i.e., alkyl acrylate monomers) include straight-chain or branched monofunctional unsaturated acrylates or methacrylates of non-tert-alkyl alcohols, wherein the alkyl group has 4 to 14 carbon atoms, and specifically 4 to 12 carbon atoms. Typically, poly(meth)acrylic acid pressure-sensitive adhesives are derived from, for example, at least one (meth)acrylic acid alkyl ester monomer, such as, for example, isooctyl acrylate, isononyl acrylate, 2-methyl-butyl acrylate, 2-ethyl-n-hexyl acrylate and n-butyl acrylate, isobutyl acrylate, hexyl acrylate, n-octyl acrylate, n-octyl methacrylate, n-nonyl acrylate, isoamyl acrylate, n-decyl acrylate, isodecyl acrylate, isodecyl methacrylate, isobornyl acrylate, 4-methyl-2-pentyl acrylate and dodecyl acrylate; and at least one comonomer component, such as, for example, (meth)acrylic acid, vinyl acetate, N-vinylpyrrolidone, (meth)acrylamide, vinyl ester, fumarate, styrene macromonomer, alkyl maleate and alkyl fumarate (based on maleic acid and fumarate, respectively), or combinations thereof.

[0045] Particularly suitable (meth)acrylate-based pressure-sensitive adhesives include copolymers derived from: (A) at least one mono-olefinically unsaturated alkyl (meth)acrylate monomer (i.e., alkyl acrylate and alkyl methacrylate monomers); and (B) at least one reinforcing monomer of a mono-olefinically unsaturated free radical copolymer. The reinforcing monomer has a higher homopolymer glass transition temperature (Tg) than the homopolymer glass transition temperature of the alkyl (meth)acrylate monomer and is the monomer that improves the glass transition temperature and cohesive strength of the resulting copolymer. In this document, "copolymer" refers to a polymer containing two or more different monomers, including terpolymers, tetrpolymers, etc.

[0046] Monomer A is a monoolefinically unsaturated alkyl acrylate or alkyl methacrylate (i.e., (meth)acrylate), which contributes to the flexibility and adhesion of the copolymer. Generally, the homopolymer Tg of monomer A is not higher than about 0°C. Typically, the alkyl group of the (meth)acrylate has an average of about 4 to about 20 carbon atoms, or an average of about 4 to about 14 carbon atoms. The alkyl group may optionally contain oxygen atoms in the chain, thereby forming, for example, ethers or alkoxy ethers. Examples of monomer A include, but are not limited to, 2-methylbutyl acrylate, isooctyl acrylate, lauryl acrylate, 4-methyl-2-pentyl acrylate, isoamyl acrylate, sec-butyl acrylate, n-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-decyl acrylate, isodecyl acrylate, isodecyl methacrylate, and isononyl acrylate. Other examples include, but are not limited to (meth)acrylate monomers containing heteroatoms or heteroatom groups (such as hydroxyl groups or heteroalkylene groups). Examples of such monomers include HEA (hydroxyethyl acrylate), HEMA (hydroxyethyl methacrylate), polyethoxylated or polypropoxylated methoxy (meth)acrylates, such as acrylates from CARBOWAX (commercially available from Union Carbide) and NK ester AM90G (commercially available from Shin Nakamura Chemical Co., Ltd., Japan). Copolymers can be prepared using combinations of various monomers classified as monomer A.

[0047] Monomer B, a reinforcing monomer for monoolefin-bonded unsaturated free radical copolymerization, increases the glass transition temperature and cohesive strength of the copolymer. Generally, monomer B has a homopolymer Tg of at least about 10 °C. Typically, monomer B is a reinforcing (meth)acrylic acid monomer, including acrylic acid, methacrylic acid, acrylamide, or (meth)acrylate. Examples of monomer B include, but are not limited to, acrylamides such as acrylamide, methacrylamide, N-methylacrylamide, N-ethylacrylamide, N-hydroxyethylacrylamide, diacetone acrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, N-ethyl-N-aminoethylacrylamide, N-ethyl-N-hydroxyethylacrylamide, N,N-dihydroxyethylacrylamide, tert-butylacrylamide, N,N-dimethylaminoethylacrylamide, and N-octylacrylamide. Other examples of monomer B include itaconic acid, crotonic acid, maleic acid, fumaric acid, 2,2-(diethoxy)ethyl acrylate, 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, 3-hydroxypropyl acrylate or 3-hydroxypropyl methacrylate, methyl methacrylate, isobornyl acrylate, 2-(phenoxy)ethyl acrylate or 2-(phenoxy)ethyl methacrylate, biphenyl acrylate, tert-butylphenyl acrylate, cyclohexyl acrylate, dimethyl adamantane acrylate, 2-naphthyl acrylate, phenyl acrylate, N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone, and N-vinylcaprolactam. Particularly suitable reinforcing acrylic monomers that can be used as monomer B include acrylic acid and acrylamide. Combinations of various reinforcing monoolefin unsaturated monomers classified as monomer B can be used to prepare copolymers. In some embodiments, optically transparent pressure-sensitive adhesives comprise (meth)acrylate copolymers of 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl acrylate, and acrylamide.

[0048] Another example of a suitable (meth)acrylate-based pressure-sensitive adhesive is the radiation-curable pressure-sensitive adhesive described in PCT Publication No. 2013 / 025443. This adhesive is a (meth)acrylate copolymer having radiation-reactive sites. Typically, the radiation-reactive sites are photocrosslinkable sites, and more typically, UV-crosslinkable sites. The (meth)acrylate copolymer is prepared from two or more types of monomers. At least one of these monomers is a (meth)acrylate monomer having radiation-reactive sites. Typically, the amount of the (meth)acrylate monomer having radiation-reactive sites is about 0.1% by weight, about 0.2% by weight, or about 0.3% by weight, based on the total weight of the monomers.

[0049] In some embodiments, the radiation-reactive site is a UV-crosslinkable site. Examples include structures capable of being excited by UV irradiation and abstracting hydrogen radicals from within the same molecule or from different (meth)acrylic acid copolymer molecules. Examples of such structures include benzophenone, benzyl, o-benzoylbenzoate structures, thioxantone, ketocoumarin, ethylanthoraquinone, camphorquinone, etc. All of the above structures are capable of being excited by UV irradiation and abstracting hydrogen radicals from (meth)acrylic acid copolymer molecules to form free radicals that can form crosslinking agents. Benzophenone is particularly suitable. Examples of suitable monomers include (meth)acrylates having a benzophenone structure, such as 4-acryloyloxybenzophenone, 4-acryloyloxyethoxybenzophenone, 4-acryloyloxy-4'-methoxybenzophenone, 4-acryloyloxyethoxy-4'-methoxybenzophenone, 4-acryloyloxy-4'-bromobenzophenone, 4-acryloyloxyethoxy-4'-bromobenzophenone, 4-methacryloyloxybenzophenone, 4-methacryloyloxyethoxybenzophenone, 4-methacryloyloxy-4'-methoxybenzophenone, 4-methacryloyloxyethoxy-4'-bromobenzophenone, 4-methacryloyloxyethoxy-4'-bromobenzophenone, and mixtures thereof.

[0050] In addition to monomers containing radiation-reactive sites, (meth)acrylate copolymers typically contain alkyl (meth)acrylates, with the alkyl groups usually having 2 to 26 carbon atoms. Examples of suitable (meth)acrylate monomers include ethyl acrylate, ethyl methacrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, hexyl acrylate, hexyl methacrylate, n-octyl acrylate, n-octyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, isoamyl acrylate, isooctyl acrylate, isononyl acrylate, decyl acrylate, isodecyl acrylate, isodecyl methacrylate, lauryl acrylate, lauryl methacrylate, and tridecane acrylate. Tridecyl methacrylate, tetradecyl acrylate, tetradecyl methacrylate, hexadecyl acrylate, hexadecyl methacrylate, stearyl acrylate, stearyl methacrylate, isostearyl acrylate, isostearyl methacrylate, eicosane acrylate, eicosane methacrylate, hexadecyl acrylate, hexadecyl methacrylate, 2-methylbutyl acrylate, 4-methyl-2-pentyl acrylate, 4-tert-butylcyclohexyl methacrylate, cyclohexyl methacrylate, isobornyl acrylate, and mixtures thereof. Typically, one or more alkyl (meth)acrylate monomers are present in an amount of 60%, 70%, or 80% by weight, based on the total weight of the monomers. In some embodiments, based on the total weight of the monomers, it is about 95% by weight or less, 92% by weight or less, or 90% by weight or less.

[0051] Another potentially suitable class of optically transparent pressure-sensitive adhesives is siloxane adhesives. Siloxane pressure-sensitive adhesives include those described in the following documents, for example, U.S. Patent Nos. 5,527,578 and 5,858,545; and PCT Publication No. WO00 / 02966. Specific examples include polydiorganosiloxane polyurea copolymers and blends thereof, such as those described in U.S. Patent No. 6,007,914, and polysiloxane-polyalkylene block copolymers. Other examples of siloxane pressure-sensitive adhesives include those formed from silanols, organosilicon hydrides, siloxanes, epoxides, and (meth)acrylates. When a siloxane pressure-sensitive adhesive is prepared from a (meth)acrylate-functionalized siloxane, the adhesive is sometimes referred to as a siloxane (meth)acrylate.

[0052] A wide variety of IR absorbing materials are suitable for use in the optically transparent adhesives of this disclosure. In some embodiments, the infrared absorbing material comprises an infrared absorbing dye. In other embodiments, the infrared absorbing material comprises infrared absorbing nanoparticles. In still other embodiments, the infrared absorbing material comprises a combination of infrared absorbing dyes and infrared absorbing nanoparticles. Typically, the infrared absorbing nanoparticles comprise aggregated infrared absorbing dyes. In these embodiments, some dyes may be dispersed in a matrix, and some dyes may remain undispersed as nanoparticles.

[0053] A wide variety of infrared-absorbing dyes are suitable. Dyes are typically aromatic compounds or salts that absorb light in at least some portions of the infrared spectrum. Examples of infrared-absorbing dyes include diimino-onium dyes, anthraquinone dyes, amine-onium dyes, cyanine dyes, quinoline-onium dyes, ketone-onium dyes, aromatic-onium dyes, naphthalene-triphenylene dyes (which encompass tetranaphthalene-triphenylene and dinaphthalene-triphenylene, and other higher-order analog dyes and trinaphthalene-diphenylene dyes listed below), chamomile-onium dyes, polymethimide dyes, naphthoquinone dyes, pyranonium dyes, phthalocyanine dyes, naphthocyanin dyes, naphtholactam dyes, azo dyes, indigo dyes, pyrenone dyes, trinaphthalene-diphenylene dyes, dioxazine dyes, quinacridone dyes, isoindoleone dyes, quinoline phthalone dyes, pyrrole dyes, or thio-indigo dyes.

[0054] Suitable infrared absorbing dyes are those that are commercially available from BASF under the trade name LUMOGEN, such as LUMOGEN IR765 and LUMOGEN IR788; those known as “WDR-3” (CAS#211991-63-8) and “DBT BF4” (CAS#494762-23-1); those available from Epolin under the trade name EPOLIGHT, such as EPOLIGHT5839, EPOLIGHT 1117 and EPOLIGHT 1178; and SDA 7293 available from HWSand.

[0055] In some embodiments, the IR light-absorbing dye or dye combination is present in the polymer adhesive matrix at an amount of 0.1% to 10% by weight, based on the total dry weight of the matrix. In some embodiments, the IR light-absorbing dye or dye combination is present in the polymer adhesive matrix at an amount of 1% to 10% by weight, or even 2% to 8% by weight, or even 2% to 6% by weight, based on the total dry weight of the matrix.

[0056] The multilayer film article of the present invention includes a first optical film, referred to herein as the first optical film. In some embodiments, the optical film includes a single-layer optical film. In other embodiments, the optical film includes a multilayer optical film.

[0057] As used herein, the term "optical film" refers to a film that can be used to produce optical effects. Optical films are typically polymer-containing films and can be single-layered or multi-layered. Optical films are flexible and can have any suitable thickness. These optical films are typically at least partially transmissive, reflective, antireflective, polarized, optically transparent, or diffuse relative to certain wavelengths of the electromagnetic spectrum (e.g., wavelengths in the visible, ultraviolet, or infrared regions of the electromagnetic spectrum). Exemplary optical films include, but are not limited to: visible specular films, colored specular films, solar reflective films, collimating films, ultraviolet reflective films, brightness enhancement films, reflective polarizing films (such as double brightness enhancement films), absorptive polarizing films, optically transparent films, colored films, and antireflective films.

[0058] Some optical films have multiple layers, such as multiple layers containing polymeric materials (e.g., polymers with or without dyes), or multiple layers containing metallic and polymeric materials. Some optical films have alternating layers of polymeric materials with different refractive indices. Other optical films have alternating polymeric and metallic layers. Exemplary optical films are described in the following patents: U.S. Patent No. 6,049,419 (Wheatley et al.); U.S. Patent No. 5,223,465 (Wheatley et al.); U.S. Patent No. 5,882,774 (Jonza et al.); U.S. Patent No. 6,049,419 (Wheatley et al.); U.S. Patent No. RE 34,605 ​​(Schrenk et al.); U.S. Patent No. 5,579,162 (Bjornard et al.); and U.S. Patent No. 5,360,659 (Arends et al.).

[0059] In some embodiments, the multilayer film article further includes a second optical film, wherein the second optical film has a first main surface and a second main surface, wherein the first main surface of the second optical film is in contact with at least a portion of the second main surface of the optically transparent adhesive layer.

[0060] Similar to the first optical film, the second optical film may comprise a single-layer or multi-layer optical film. The films described above for the first optical film also apply to the second optical film. The first and second optical films may be the same or different.

[0061] This document also discloses an optical device. The optical device includes a visible light source, a visible light detector, and a multilayer film article situated in the path between the visible light source and the visible light detector. The multilayer film article, as described above, transmits visible light and absorbs IR light. In some embodiments, the multilayer film article includes a first optical film layer having a first main surface and a second main surface, and an optically transparent adhesive layer having a first main surface and a second main surface, wherein the first main surface of the optically transparent adhesive layer is disposed on at least a portion of the second main surface of the first optical film layer. As described above, the optically transparent adhesive layer includes a polymer adhesive matrix and at least one infrared light absorbing material that absorbs light in the range of 680 nm to 1100 nm. In some embodiments, the ratio of the minimum transmittance of the at least one infrared light absorbing material in the range of 680 nm to 1100 nm to the transmittance at 500 nm is 0 to 0.5. In some embodiments, this ratio is less than 0.4, less than 0.3, less than 0.2, less than 0.1, or even less than 0.05.

[0062] Suitable optically transparent adhesives, IR light-absorbing materials, and optical films have been described in detail above. In some embodiments, the multilayer film article further includes a second optical film having a first main surface and a second main surface, wherein the first main surface of the second optical film is in contact with at least a portion of the second main surface of the optically transparent adhesive layer.

[0063] Examples of optical devices disclosed herein are sensing devices. Examples of sensing devices are fingerprint sensing devices. This disclosure can be more fully understood by referring to the accompanying drawings. The embodiments are discussed in the following section. Figures 1 to 7 . Figure 8 A cross-sectional view of an optical device 300 is shown. The optical device 300 is configured to sense the presence of a finger 10. The optical device 300 includes a multilayer structure comprising an emitting display 20, a light redirection film 90, a multilayer film layer 50, and a visible light detector 40. The emitting display 20 is configured to emit a visible image 21 in the visible wavelength range of approximately 420 nm to approximately 680 nm. Visible light sources 30, 31, and 32 are configured to emit light 30a, 31a, and 32a having a first wavelength 64 in the visible wavelength range. The visible light detector 40 is configured to detect emitted light after it has been reflected by the finger 10 as 30b, 31b, and 32b. The light redirection film 90 is designed to change the direction of the emitted light (30b, 31b, 32b) reflected from the finger 10. The light redirection film 90 includes at least one optical lens 91. The multilayer film layer 50 is located in the optical path between the visible light source and the visible light detector, and... Figure 9 It is shown in more detail below.

[0064] Figure 9A cross-sectional view of the multilayer film article 50 of the aforementioned device 300 is shown. The multilayer film article 50 includes a first multilayer optical film layer 60 and an optically transparent adhesive layer 80. The first multilayer optical film layer 60 includes a plurality of alternating polymer layers 61 and 62, totaling at least 10 layers, each polymer layer having an average thickness of less than about 400 nm. The multilayer film layer 60 is configured such that, for incident light 70 incident on the first optical film layer and for at least one polarization state (x-axis), the plurality of polymer layers reflect at least 70% of incident light having a first wavelength 64 in the visible wavelength range for each of a first incident angle (θ) less than about 5 degrees and a second incident angle greater than about 45 degrees, and reflect at least 70% of incident light having a second wavelength 65 in the infrared wavelength range extending from about 680 nm to about 1100 nm for the first incident angle. The multilayer film layer 60 transmits at least 40% of the incident light having the second wavelength 65 for the second incident light. The multilayer article 60 optionally further includes one or more surface layers 63, each surface layer having an average thickness greater than about 500 nm. The optically transparent adhesive layer 80 includes a polymer adhesive matrix and at least one infrared light absorbing material that absorbs light having a second wavelength.

[0065] Figure 10 A graph showing the transmittance % of a multilayer article 60, which does not include an optically transparent adhesive layer 80 having an infrared-absorbing material, is shown. The graph indicates that, for incident light at an angle of 60°, the multilayer article allows the transmission of infrared light with a wavelength of 65. The optically transparent adhesive layer 80 of the article disclosed herein is designed to absorb this infrared light that is not reflected by the multilayer article 60.

[0066] Example

[0067] These examples are for illustrative purposes only and are not intended to limit the scope of the appended claims. Unless otherwise specified, all parts, percentages, ratios, etc., in the examples and the remainder of the specification are by weight. Unless otherwise specified, all solvents and other reagents used are available from Sigma-Aldrich Chemical; Milwaukee, Wisconsin.

[0068] Abbreviation Table

[0069]

[0070] Test methods

[0071] Transmittance %

[0072] The transmittance of the samples was tested in the wavelength range of 400 nm to 1200 nm using a Lambda 900 spectrophotometer.

[0073] Preparation of dyeing polymer solution

[0074] Solution 1 :

[0075] 0.0106 g of DYE-4 (IR 788) was added to 2.14 g of toluene, sonicated for 1 hour, and then mixed with a methyl ethyl ketone solution of 1.32 g of 15% CAB. The CAB polymer solution partially separated and had to be sonicated to redissolve the CAB with the toluene-dye blend.

[0076] Solution 2 :

[0077] 0.0128 g of DYE-3 (IR 765) was added to 1.736 g of 1-methoxy-2-propanol, sonicated for 1 hour, and then mixed with 1.70 g of 15% CAB in a methyl ethyl ketone solution.

[0078] Solution 3 :

[0079] Add 0.0105 g of DYE-1 (WDR-3) to 2.01 g of methyl ethyl ketone, sonicate for 1 hour, and then mix with 1.35 g of methyl ethyl ketone solution of 15% CAB.

[0080] Solution 4 :

[0081] Add 0.0101 g of DYE-2 (DBT BF4) to 2.00 g of methyl ethyl ketone, sonicate for 1 hour, and then mix with 1.36 g of methyl ethyl ketone solution of 15% CAB.

[0082] Examples 1 to 4 (DCC1 to DCC4) of dye-containing coatings

[0083] Examples DCC1 to DCC4 were prepared as follows: Each of solutions 1 to 4 was coated onto a PET film using a #26 wire-wound Meyer rod, and each coating was dried at 160℉ (71°C) for 2 minutes. Transmittance % was measured and... Figure 1 As shown in the image.

[0084] Preparation of (meth)acrylate adhesive-1

[0085] A mixture of 2-EHA / EHMA / HEA / Acm in a mass ratio of 65 / 18 / 14 / 3 was prepared and diluted with ethyl acetate to provide a monomer concentration of 50% by mass. An initiator was then added at a ratio based on 0.15% by mass of the monomer component, and the mixture was placed in a glass vial and purged with nitrogen for 10 minutes. The vial was then sealed and kept under an inert atmosphere in a constant temperature bath at 55°C for 6 hours. The reaction temperature was then increased to 75°C and maintained for another 4 hours. A clear, viscous solution was obtained. The weight-average molecular weight of the obtained acrylic copolymer was 563,000 Daltons, as measured by gel permeation chromatography against a polystyrene standard.

[0086] Preparation and testing of dye-containing adhesives Examples 1 to 6 (DCAE-1 to DCAE-6) Adhesive Example 1 (DCAE-1)

[0087] Based on the dry copolymer mass, silane, polyisocyanate, and DYE-1 were added to a solution of (meth)acrylate adhesive-1 at ratios of 0.05 wt%, 0.6 wt%, and 2 wt%, respectively. The prepared solution was coated onto pad-1 and dried in an oven at 70°C for 20 minutes. After drying, the PSA thickness was 25 micrometers. Subsequently, this PSA surface was laminated to pad-2. Transmittance was measured, as shown in the figure. Figure 2 As shown.

[0088] Adhesive Example-2 (DCAE-2)

[0089] Based on the dry copolymer mass, silane, polyisocyanate, DYE-1, and DYE-5 were added to a solution of (meth)acrylate adhesive-1 at ratios of 0.05 wt%, 0.6 wt%, 2 wt%, and 2 wt%, respectively. The prepared solution was coated onto pad-1 and dried in an oven at 70°C for 20 minutes. After drying, the PSA thickness was 25 micrometers. Subsequently, the PSA surface was laminated to pad-2. Transmittance was measured, as shown in the figure. Figure 3 As shown.

[0090] Adhesive Example 3 (DCAE-3)

[0091] Based on the dry copolymer mass, silane, polyisocyanate, DYE-1, DYE-5, and DYE-3 were added to a solution of (meth)acrylate adhesive-1 at ratios of 0.05 wt%, 0.6 wt%, 2 wt%, 2 wt%, and 0.2 wt%, respectively. The prepared solution was coated onto pad-1 and dried in an oven at 70°C for 20 minutes. After drying, the PSA thickness was 25 micrometers. Subsequently, the PSA surface was laminated to pad-2. Transmittance was measured, as shown in the figure. Figure 4 As shown.

[0092] Adhesive Example 4 (DCAE-4)

[0093] Based on the dry copolymer mass, silane, polyisocyanate, DYE-1, and DYE-6 were added to a solution of (meth)acrylate adhesive-1 at ratios of 0.05 wt%, 0.6 wt%, 2 wt%, and 1.5 wt%, respectively. The prepared solution was coated onto pad-1 and dried in an oven at 70°C for 20 minutes. After drying, the PSA thickness was 25 micrometers. Subsequently, the PSA surface was laminated to pad-2. Transmittance was measured, as shown in the figure. Figure 5 As shown.

[0094] Adhesive Example-5 (DCAE-5)

[0095] Based on the dry copolymer mass, silane, polyisocyanate, DYE-1, and DYE-7 were added to a solution of (meth)acrylate adhesive-1 at ratios of 0.05 wt%, 0.6 wt%, 2 wt%, and 1.5 wt%, respectively. The prepared solution was coated onto pad-1 and dried in an oven at 70°C for 20 minutes. After drying, the PSA thickness was 25 micrometers. Subsequently, the PSA surface was laminated to pad-2. Transmittance was measured, as shown in the figure. Figure 6 As shown.

[0096] Adhesive Example 6 (DCAE-6)

[0097] Based on the dry copolymer mass, silane, polyisocyanate, and DYE-8 were added to a solution of (meth)acrylate adhesive-1 at ratios of 0.05 wt%, 0.6 wt%, 2 wt%, and 1.5 wt%, respectively. The prepared solution was coated onto pad-1 and dried in an oven at 70°C for 20 minutes. After drying, the PSA thickness was 25 micrometers. Subsequently, the PSA surface was laminated to pad-2. Transmittance was measured, as shown in the figure. Figure 7 As shown.

Claims

1. An optical device (300) configured to sense the presence of a finger (10), the optical device comprising: The emitting display (20) is configured to emit a visible image (21) in a visible wavelength range extending from 420 nm to 680 nm. Visible light sources (30, 31, 32) are configured to emit light (30a, 31a, 32a) having a first wavelength (64) within the visible wavelength range. A visible light detector (40) is configured to detect emitted light after the emitted light is reflected (30b, 31b, 32b) by the finger; and Multilayer film article (50), the multilayer film article being located in the path between the visible light source and the visible light detector, wherein the multilayer film article comprises: A first optical film layer (60) comprising a plurality of polymer layers (61, 62) totaling at least 10 layers, each polymer layer having an average thickness of less than 400 nm, such that for incident light (70) incident on the first optical film layer and for at least one polarization state (x-axis), the plurality of polymer layers: For each of a first incident angle (θ) less than 5 degrees and a second incident angle greater than 45 degrees, at least 70% of the incident light having the first wavelength is reflected; The incident light reflected at the first incident angle has at least 70% of a second wavelength (65) in the infrared wavelength range extending from 680 nm to 1100 nm; and At least 40% of the incident light having the second wavelength is transmitted at the second incident angle; and Optically transparent adhesive layer (80). The optically transparent adhesive layer is disposed on at least a portion of the first optical film layer. And the optically transparent adhesive layer comprises: Polymer adhesive matrix; and At least one infrared light absorbing material, wherein the at least one infrared light absorbing material absorbs light having the second wavelength.

2. The optical device according to claim 1, wherein the ratio of the minimum transmittance of the at least one infrared light absorbing material at 680 nm to 1100 nm to the transmittance at 500 nm is 0 to 0.

5.

3. A multilayer film article for a fingerprint sensor, the multilayer film article comprising: A first optical film layer having a first main surface and a second main surface, the first optical film layer comprising a plurality of polymer layers totaling at least 10 layers, each of the polymer layers having an average thickness of less than 400 nm, such that for incident light incident on the first optical film layer and for at least one polarization state, the plurality of polymer layers: For each of a first incident angle less than 5 degrees and a second incident angle greater than 45 degrees, at least 70% of the incident light having a first wavelength in the visible wavelength range is reflected; The incident light reflected at the first incident angle has at least 70% of a second wavelength in the infrared wavelength range extending from 680 nm to 1100 nm; and At least 40% of the incident light having the second wavelength is transmitted at the second incident angle; and An optically transparent adhesive layer having a first main surface and a second main surface, wherein the first main surface of the optically transparent adhesive layer is disposed on at least a portion of the second main surface of the first optical film layer, and wherein the optically transparent adhesive layer comprises: Polymer adhesive matrix; and At least one infrared light absorbing material, wherein the at least one infrared light absorbing material absorbs light in the range of 680 nanometers to 1100 nanometers.

4. The multilayer film article according to claim 3, wherein the ratio of the minimum transmittance of the at least one infrared light absorbing material at 680 nm to 1100 nm to the transmittance at 500 nm is 0 to 0.

5.

5. The multilayer film article according to claim 3, wherein the first optical film layer comprises a single-layer optical film or a multilayer optical film.

6. The multilayer film article according to claim 3, further comprising a second optical film, wherein the second optical film has a first main surface and a second main surface, wherein the first main surface of the second optical film is in contact with at least a portion of the second main surface of the optically transparent adhesive layer.

7. A multilayer film article for use in a fingerprint sensor, the multilayer film article comprising: A first optical film layer having a first main surface and a second main surface, the first optical film layer comprising a plurality of polymer layers totaling at least 10 layers, each of the polymer layers having an average thickness of less than 400 nm, such that for incident light incident on the first optical film layer and for at least one polarization state, the plurality of polymer layers: For each of a first incident angle less than 5 degrees and a second incident angle greater than 45 degrees, at least 70% of the incident light having a first wavelength in the visible wavelength range is reflected; The incident light reflected at the first incident angle has at least 70% of a second wavelength in the infrared wavelength range extending from 680 nm to 1100 nm; and At least 40% of the incident light having the second wavelength is transmitted at the second incident angle; and An optically transparent adhesive layer having a first main surface and a second main surface, wherein the first main surface of the optically transparent adhesive layer is disposed on at least a portion of the second main surface of the first optical film layer, and wherein the optically transparent adhesive layer comprises: Polymer adhesive matrix; and At least one infrared light absorbing material, wherein the at least one infrared light absorbing material comprises diiminoonium dye, anthraquinone dye, amineonium dye, cyanine dye, cyanonium dye, ketoneonium dye, arylonium dye, naphthalene-benzene dye, chamomile-cycloonium dye, polymethimide dye, naphthoquinone dye, pyridinium dye, phthalocyanine dye, naphthalene-phthalocyanine dye, naphtholactam dye, azo dye, indigo dye, pyrenone dye, trinaphthalene-diphenylene dye, dioxazine dye, quinacridone dye, isoindoleone dye, quinoline phthalone dye, pyrrole dye, or thioindigo dye.

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