KR20120099704A - Light-emitting diode (led) devices comprising nanocrystals - Google Patents

Abstract

The present invention provides light emitting diode (LED) devices comprising a container and compositions of hermetically sealed luminescent nanocrystals. The present invention also provides a display comprising LED devices. Suitably, the LED devices are white light LED devices.

Description

LIGHT-EMITTING DIODE (LED) DEVICES COMPRISING NANOCRYSTALS}

The present invention relates to a light-emitting diode (LED) comprising light emitting nanocrystals, suitably a white light LED device method. The invention also relates to display systems comprising LED devices.

Luminescent nanocrystals are oxidatively damaged upon exposure to air and moisture, often resulting in loss of luminescence. The use of luminescent nanocrystals in applications such as down-conversion and filtering layers often exposes the luminescent nanocrystals to elevated temperatures, high light intensity, gases and moisture in the environment. Together with the requirements for long luminescent lifetimes in these applications, these factors often limit the use of luminescent nanocrystals or require frequent replacement. Accordingly, there is a need for a method and composition that hermetically seals luminescent nanocrystals to increase their service life and luminescence intensity.

There is also a need for light emitting diode (LED) devices using hermetically sealed nanocrystals, including white light LED devices.

Brief Summary of the Invention

In one embodiment, the present invention provides light emitting diode (LED) devices. LED devices suitably include a hermetically sealed container containing a plurality of luminescent nanocrystals and a blue luminescent LED. The vessel is disposed relative to the LED to facilitate down conversion of the luminescent nanocrystals.

Suitable hermetically sealed containers include plastic or glass tubes, such as glass capillaries. In an exemplary embodiment, the hermetically sealed container is spaced apart from the LED. Suitably, the luminescent nanocrystals emit green light and red light. Exemplary luminescent nanocrystals for use in LED devices include CdSe or ZnS and include cores / shells including CdSe / ZnS, InP / ZnS, PbSe / PbS, CdSe / CdS, CdTe / CdS or CdTe / ZnS Luminescent nanocrystals that are luminescent nanocrystals. In exemplary embodiments, luminescent nanocrystals are dispersed in a polymeric matrix. The present invention also provides display systems comprising LED devices.

In further embodiments, the present invention provides a light emitting diode comprising an LED, a hermetically sealed container comprising a plurality of luminescent nanocrystals optically connected to the LED, and a light guide optically connected to the hermetically sealed container ( LED) devices. Suitably, the first portion of light emitted from the LED is down converted by the luminescent nanocrystals, and the second portion of light emitted from the LED, and the down converted light from the luminescent nanocrystals are emitted from the light guide.

In exemplary embodiments, the LED emits blue light. Suitably, the first portion of blue light emitted from the LED is down converted to green light and red light by the light emitting nanocrystals. The second portion of blue light, green light and red light are suitably combined to produce white light.

Exemplary hermetically sealed containers include plastic or glass containers, such as glass capillaries having at least one dimension from about 100 μm to about 1 mm. Suitably, the luminescent nanocrystals may be core / shell luminescent nanocrystals, including CdSe or ZnS and comprising CdSe / ZnS, InP / ZnS, PbSe / PbS, CdSe / CdS, CdTe / CdS or CdTe / ZnS have. Luminescent nanocrystals can be dispersed in a polymeric matrix. In a suitable embodiment, the hermetically sealed container is spaced apart from the LED. In embodiments, the LED devices of the present invention are white light LED devices.

The present invention also provides display systems comprising a plurality of LED devices and a display described herein. Suitably, the display at least partially surrounds the light guide. The first portion of light emitted from the LED is down converted by the luminescent nanocrystals, and the second portion of light emitted from the LED, and the down converted light from the luminescent nanocrystals is emitted from the light guide and displayed on the display. . In an exemplary embodiment, the hermetically sealed container is optically connected to at least two LEDs.

In yet another embodiment, the present invention provides a composite material. The composite material includes a first polymeric material having a first composition. The composite material also includes a second polymeric material having a second composition, and a plurality of luminescent nanocrystals dispersed in the second polymeric material. The second polymeric material is dispersed in the first polymeric material.

Suitably, the first polymeric material comprises epoxy or polycarbonate and the second polymeric material comprises aminosilicone. In embodiments, the luminescent nanocrystals emit green light and / or red light. Suitably, the luminescent nanocrystals comprise CdSe or ZnS, or core / shell luminescent nanocrystals comprising CdSe / ZnS, InP / ZnS, PbSe / PbS, CdSe / CdS, CdTe / CdS or CdTe / ZnS Can be. In further embodiments, the composite material includes an inorganic layer of SiO ₂ , TiO ₂ or AlO ₂ that hermetically seals the composite material. Suitably, the composite material has an optical density of about 0.5 to about 0.9 (eg about 0.8) and a path length of about 50 μm to about 200 μm (eg about 100 μm) at a blue LED wavelength.

The present invention also provides methods for producing luminescent nanocrystal composite materials. The methods suitably include dispersing a plurality of luminescent nanocrystals in the first polymeric material to form a mixture of luminescent nanocrystals and the first polymeric material. The mixture is cured and particles are produced from the cured mixture. The particles are dispersed in the second polymeric material to produce a composite material. Suitably, the crosslinking agent is added to the mixture before curing. In exemplary embodiments, the particles are produced by ball milling the cured mixture. The composite material can be formed into a film.

In further embodiments, the present invention provides light emitting diode (LED) devices. LED devices include an LED, a light guide optically connected to the LED, and a plurality of luminescent nanocrystals dispersed in an area within the light guide, the area extending along the length of the light guide. Light emitted from the LED is down converted by the nanocrystals and exits the surface of the light guide. Suitably, the luminescent nanocrystals emit blue light, green light and red light, and the LED emits ultraviolet light. Blue light, red light and green light combine to produce white light.

In still other embodiments, the first portion of light emitted from the LED is down converted by the luminescent nanocrystals, and the second portion of light emitted from the LED and the down converted light exit the surface of the light guide. Suitably, the LED emits blue light. The first portion of blue light emitted from the LED is down converted to green and red light by the luminescent nanocrystals, and the second portion of the blue light, green light and red light are suitably combined to produce white light.

Exemplary nanocrystals for use in LED devices include CdSe or ZnS and core / shell including CdSe / ZnS, InP / ZnS, PbSe / PbS, CdSe / CdS, CdTe / CdS or CdTe / ZnS It may be luminescent nanocrystals.

Suitably, the light guide comprises one or more reflectors. The area in the light guide is suitably a layer of luminescent nanocrystals. In exemplary embodiments, the region has a thickness that varies along the length of the light guide, suitably increasing (eg, linearly) along the length of the light guide from the LED. In exemplary embodiments, the LED devices are white light LED devices. The present invention also provides displays that include LED devices.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof and in the accompanying drawings.

The foregoing general description and the following detailed description are for purposes of illustration and description, and are intended to further explain the claimed invention.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate the invention, and together with the description serve to explain the principles of the invention, to help those skilled in the art to make and use the invention.
1 shows a hermetically sealed luminescent nanocrystal composition according to one embodiment of the invention.
2 illustrates a method for hermetically sealing a container including nanocrystals according to one embodiment of the present invention.
3 shows hermetically sealed luminescent nanocrystal compositions comprising individual hermetically sealed compositions according to one embodiment of the invention.
4 shows a hermetically sealed container containing luminescent nanocrystals according to one embodiment of the invention.
5 shows a hermetically sealed composition further comprising microlenses in accordance with one embodiment of the present invention.
6A-6C show a hermetically sealed composition further comprising a light-focusing device according to one embodiment of the invention.
7A shows an LED device according to one embodiment of the invention.
7B shows the down conversion of light from the LED device of the present invention.
8A-8C show variations of the LED device of the present invention.
9 shows an LED device of the present invention comprising a reflector.
10A-10B show hermetically sealed capillaries in accordance with embodiments of the present invention.
11 shows a display device according to one embodiment of the invention.
12 illustrates a luminescent nanocrystal composite material according to one embodiment of the invention.
13 shows a flowchart of a method of manufacturing a luminescent nanocrystal composite material according to one embodiment of the present invention.
FIG. 14 illustrates an LED device including a light guide having a region of nanocrystals in accordance with an embodiment of the present invention.
15 (a)-15 (c) show light intensity output for an LED device that includes a light guide having regions of nanocrystals.
16 (a) -16 (c) show light intensity output for an LED device including a light guide having an area of increasing nanocrystals of thickness.
Hereinafter, the present invention will be described with reference to the accompanying drawings. In the drawings, like reference numerals refer to the same or functionally similar components.

It is to be understood that the specific embodiments shown and described herein are examples of the invention only and are not intended to limit the scope of the invention in any way. For practical clarity, conventional electronic components, manufacturing methods, semiconductor devices, and nanocrystals, nanowires, nanorods, nanotubes, and other nanoribbon technologies and systems Functional aspects (and parts of the individual operating components of the system) may not be described in detail herein.

The present invention provides various compositions comprising nanocrystals, including luminescent nanocrystals. Various properties of the luminescent nanocrystals, including their absorption properties, emission properties, and refractive index properties, can be tailored and adjusted for a variety of applications. As used herein, the term "nanocrystal" refers to a nanostructure that is substantially monocrystalline. Nanocrystals are less than about 500 nm and have at least one region or characteristic dimension with dimensions descending to an order of less than about 1 nm. As used herein, when referring to any numerical value, "about" refers to a value of ± 10% of the stated value (e.g., "about 100 nm" refers to a value between 90 nm and 90% including both boundaries. To cover a size range of 110 nm). The terms "nanocrystal", "nanodot", "dot", and "quantum dot" are easily understood by those skilled in the art to refer to the same structures, and are interchangeable herein. Used. The present invention also encompasses the use of polycrystalline or amorphous nanocrystals. As used herein, the term "nanocrystal" also encompasses "luminescent nanocrystals". As used herein, the term "luminescent nanocrystals" refers to nanocrystals that emit light when excited by an external energy source (suitably light). As used herein, when describing hermetic sealing of nanocrystals, it is to be understood that in suitable embodiments, the nanocrystals are luminescent nanocrystals.

Typically, the area of characteristic dimension is along the smallest axis of the structure. Nanocrystals may be substantially homogeneous in material properties, or in certain embodiments, may be heterogeneous. The optical properties of nanocrystals can be determined by their particle size, chemical composition or surface composition. The ability to fit luminescent nanocrystal sizes in the range between about 1 nm and about 15 nm allows photoelectron emission coverage in the entire light spectrum to provide great versatility in color rendering. Particle encapsulation provides robustness against chemical and UV degradation factors.

Nanocrystals, including luminescent nanocrystals for use in the present invention, can be prepared using any method known to those skilled in the art. Suitable methods and exemplary nanocrystals are described in US patent application Ser. No. 11 / 034,216 filed Jan. 13, 2005; US Patent Application No. 10 / 796,832, filed March 10, 2004; US Patent No. 6,949,206; And US Provisional Application No. 60 / 578,236, filed June 8, 2004, each of which is hereby incorporated by reference in its entirety. Nanocrystals for use in the present invention can be made from any suitable material, including inorganic materials, and more suitably, inorganic conductors or semiconductor materials. Suitable semiconductor materials include those disclosed in US patent application Ser. No. 10 / 796,832 and include any type of semiconductor including group II-VI, group III-V, group IV-VI, and group IV semiconductors. Suitable semiconductor materials include, but are not limited to, Si, Ge, Sn, Se, Te, B, C (including diamonds), P, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si ₃ N ₄ , Ge ₃ N ₄ , Al ₂ O ₃ , (Al, Ga, In) ₂ (S, Se, Te) ₃ , Al ₂ CO, and suitable combinations of two or more such semiconductors.

In certain aspects, the semiconductor nanocrystals may comprise a dopant from the group consisting of a p-type dopant or an n-type dopant. Nanocrystals useful in the present invention may also include group II-VI or III-V semiconductors. Examples of group II-VI or group III-V semiconductor nanocrystals include any combination of elements of group II, such as Zn, Cd, and Hg, of the periodic table with elements of group VI, such as S, Se, Te, Po; And any combination of elements in group III, such as B, Al, Ga, In, and Tl, of the periodic table with elements in group V, such as N, P, As, Sb, and Bi.

Nanocrystals comprising luminescent nanocrystals useful in the present invention may be conjugated, cooperated, associated, or attached to their surface as described throughout the specification. Ligands may be further included. Suitable ligands include any group known to those of skill in the art, including those disclosed in US Patent Application No. 11 / 034,216, US Patent Application No. 10 / 656,910, and US Patent Application No. 60 / 578,236. And each of the above disclosures is incorporated herein by reference. The use of such ligands can enhance the ability of nanocrystals to incorporate into various solvents and matrices comprising polymers. Increasing the miscibility of nanocrystals in various solvents and matrices (ie, properties that can be mixed without separation) allows the nanocrystals to be polymerized so that the nanocrystals do not aggregate together and thus do not scatter light. To be distributed throughout. Such ligands are referred to herein as "miscibility-enhancing" ligands.

As used herein, the term nanocomposite refers to a matrix material comprising distributed or embedded nanocrystals. Suitable matrix materials can be any materials known to those skilled in the art, including polymeric materials, organic or inorganic oxides. The nanocomposites of the present invention can be layers, encapsulants, coatings, or films as used herein. In embodiments of the invention, when referring to layers, polymeric layers, matrices, or nanocomposites, these terms are used interchangeably, and the embodiments so described are not limited to any one type of nanocomposite, It encompasses any matrix material or layer described herein or known in the art.

Down-converting nanocomposites (eg, as disclosed in US patent application Ser. No. 11 / 034,216) absorb active light by emitting light at a second wavelength and then emitting at a second wavelength. It utilizes the emission characteristics of luminescent nanocrystals tailored to provide improved performance and efficiency. As mentioned above, the use of luminescent nanocrystals in such down-conversion applications as well as in other filtering or coating applications has been found to make nanocrystals resistant to elevated temperatures, high intensity light (eg, LED sources), external gases and moisture. It may be exposed. Exposure to such an environment can reduce the efficiency of the nanocrystals, thereby reducing the effective product life. To solve this problem, the present invention provides a method for hermetically sealing luminescent nanocrystals and a hermetically sealed container and composition comprising luminescent nanocrystals.

Luminescent Nanocrystalline Phosphor

Any method known to those skilled in the art can be used to produce nanocrystalline phosphors, but a solution-phase colloidal method is used for the controlled growth of inorganic nanomaterial phosphors. Alivisatos, A. P., "Semiconductor clusters, nanocrystals, and quantum dots," Science 271: 933 (1996); X. Peng, M. Schlamp, A. Kadavanich, A.P. Alivisatos, "Epitaxial growth of highly luminescent CdSe / CdS Core / Shell nanocrystals with photostability and electronic accessibility," J. Am. Chem. Soc. 30: 7019-7029 (1997); And in C. B. Murray, D.J. Norris, M.G. Bawendi, "Synthesis and characterization of nearly monodisperse CdE (E = sulfur, selenium, tellurium) semiconductor nanocrystallites," J. Am. Chem. Soc. 115: 8706 (1993), the disclosure of which is incorporated herein by reference in its entirety. This manufacturing process technology takes advantage of low cost processability without the need for clean rooms and expensive manufacturing equipment. In this method, metal precursors undergoing pyrolysis at high temperature are rapidly injected into the hot solution of organic surfactant molecules. These precursors react to break up into parts at elevated temperatures to form nuclei of nanocrystals. After this initial nucleation phase, the growth phase begins by adding a monomer to the growth crystals. The result is independent crystalline nanoparticles in solution with an organic surfactant molecular coating on its surface.

Using this approach, synthesis occurs by crystal growth at elevated temperatures for several minutes, followed by initial nucleation events that occur over a few seconds. Parameters such as temperature, type of surfactant present, precursor material, ratio of surfactant to monomer, and the like can be changed to change the nature and progress of the reaction. Temperature controls the structural phase, precursor degradation rate, and growth rate of nucleation events. Organic surfactant molecules coordinate both the control and solubility of the nanocrystalline shape. The ratio of surfactants to monomers, the ratio of surfactants to each other, the ratio of monomers to each other, and the individual concentrations of monomers have a great influence on the kinetics of growth.

In suitable embodiments, CdSe is used as the nanocrystals material for visible light downconversion due to the relative maturity of this material synthesis as an example. Due to the general use of surface chemistry, it is also possible to substitute nanocrystals that do not contain cadmium.

Core / Shell Luminescent Nanocrystals

In semiconductor nanocrystals, light induced emission occurs from band edge states of the nanocrystals. Band edge emission from luminescent nanocrystals competes with radial and non-radiative decay channels resulting from surface electronic states. X. Peng, et al., J. Am. Chem. Soc. 30: 7019-7029 (1997). As a result, the presence of surface defects, such as dangling bonds, provides a non-radiative rebonding center, contributing to lowering emission efficiency. An efficient and permanent way to passivate and remove surface trap states is to epitaxially grow inorganic shell materials on the surface of the nanocrystals. X. Peng, et al., J. Am. Chem. Soc. 30: 7019-7029 (1997). The shell material may be selected such that the electron levels are of type I relative to the core material (eg, to have a larger bandgap to provide a potential step of localizing electrons and holes to the core). As a result, the possibility of non-radiative recombination can be reduced.

A core-shell structure is obtained by adding an organometallic precursor comprising a shell material to a reaction mixture containing core nanocrystals. In this case, growth does not follow after the nucleation event, but the core acts as nuclei and the shells grow from the surface. The reaction temperature is kept low to favor the addition of shell material monomers to the core surface while preventing independent nucleation of the nanocrystals of the shell material. Surfactants are present in the reaction mixture to drive controlled growth of the shell material and ensure solubility. When there is a low lattice mismatch between the two materials, a uniform and epitaxially grown shell is obtained.

Exemplary materials for preparing core-shell luminescent nanocrystals include, but are not limited to, Si, Ge, Sn, Se, Te, B, C (including diamond), P, Co, Au, BN, BP, BAs , AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, ZnO, ZnS, ZnSe, ZnTe, CdS , CdSe, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si ₃ N ₄ , Ge ₃ N ₄ , Al ₂ O ₃ , (Al, Ga, In) ₂ (S, Se, Te) ₃ , Al ₂ CO, and appropriate combinations of two or more such materials. Exemplary core-shell luminescent nanocrystals for use in the practice of the present invention include, but are not limited to, CdSe / ZnS, InP / ZnS, PbSe / PbS, CdSe / CdS, CdTe / CdS, CdTe / ZnS, and the like. (Expressed as core / shell).

Hermetically sealed luminescent nanocrystal composition and a container comprising luminescent nanocrystals

In one embodiment, the present invention provides a method for hermetically sealing a composition comprising a plurality of luminescent nanocrystals. The method suitably includes disposing a barrier layer on the composition to seal the luminescent nanocrystals. As described throughout the specification, the terms "hermetic", "hermetic sealing", and "hermetically sealed" are used to penetrate or penetrate a container or composition and / or Or the composition, container, and / or in such a way that the amount of gas (eg, air) or moisture in contact with the luminescent nanocrystals is reduced to a level that does not substantially affect the performance (eg, luminescence) of the nanocrystals. Luminescent nanocrystals are used to represent the preparation. Thus, for example, "hermetically sealed composition" comprising luminescent nanocrystals is such that the performance (eg, luminescence) of the nanocrystals is substantially achieved or affected (eg, reduced). A composition is such that the amount of air (or other gas, liquid, or moisture) penetrates into the composition and does not contact the luminescent nanocrystals.

As used throughout the specification, a plurality of luminescent nanocrystals means more than one nanocrystals (ie, 2, 3, 4, 5, 10, 100, 1,000, 1,000,000, etc. nanocrystals). The composition suitably includes luminescent nanocrystals having the same composition, but in another embodiment, the plurality of luminescent nanocrystals can be various and different compositions. For example, the luminescent nanocrystals can all emit at the same wavelength, or in another embodiment, the composition can include luminescent nanocrystals emitting at different wavelengths.

As shown in FIG. 1, in one embodiment, the present invention provides a composition 100 comprising a plurality of luminescent nanocrystals 104. In the compositions of the present invention, any nanocrystal can be prepared, including those described throughout the specification, and those known in the art, for example, as disclosed in US patent application Ser. No. 11 / 034,216.

In a suitable embodiment, the composition 100 includes a plurality of luminescent nanocrystals 104 dispersed throughout the matrix 102. As used throughout, dispersed is not only uniform (ie substantially homogeneous) but also heterogeneous (ie substantially heterogeneous) nanocrystals / distribution Include. Suitable matrices for use in the compositions of the present invention include polymers and organic oxides and inorganic oxides. Suitable polymers for use in the matrix of the present invention include any polymer known to those skilled in the art that can be used for this purpose. In suitable embodiments, the polymer will be substantially translucent or substantially transparent. Such polymers include, but are not limited to, poly (vinyl butyral): poly (vinyl acetate); Epoxy; urethane; Silicone and silicone derivatives including, but not limited to, polyphenylmethylsiloxanes, polyphenylalkylsiloxanes, polydiphenylsiloxanes, polydialkylsiloxanes, fluorinated silicones, and vinyl and hydride substituted silicones; Without limitation, acrylic polymers and copolymers formed of monomers, including methylmethacrylate, butylmethacrylate, and laurylmethacrylate; Styrenic polymers; And polymers crosslinked with difunctional monomers such as divinylbenzene.

The luminescent nanocrystals used in the present invention are, for example, mixing nanocrystals in a polymer and casting a film, mixing monomers and nanocrystals and polymerizing them together, sol gel -gel) into the polymeric (or other suitable material such as wax, oil) matrix using any suitable way, such as by mixing nanocrystals to form an oxide, or any other way known to those skilled in the art. Can be. As used herein, the term "embedded" is used to indicate that luminescent nanocrystals are enclosed or encased in a polymer that constitutes most of the components of the matrix. . Note that at this point, the luminescent nanocrystals are suitably distributed evenly throughout the matrix, but in another embodiment it can be distributed according to a uniform distribution function specific to the application.

The thickness of the composition of the present invention can be controlled by any method known in the art, such as spin coating and screen printing. The luminescent nanocrystal composition of the present invention may be of any desired size, shape, configuration, and thickness. For example, the composition may be in the form of a layer, for example, in the form of a disc, sphere, cube or block, tube or other configuration. While the various compositions of the present invention may be of any desired or desired thickness, suitably, the composition may be on the order of about 100 mm thick (ie, in one dimension) and down to a degree less than about 1 mm thick. have. In another embodiment, the polymeric layer of the present invention may be on the order of tens to hundreds of microns in thickness. Luminescent nanocrystals can be embedded in various compositions / matrixes at any loading ratio appropriate for the desired function. Suitably, the luminescent nanocrystals are loaded at a rate between about 0.001% and about 75% by volume, depending on the application, the matrix, and the type of nanocrystals used. Appropriate loading ratios can be readily determined by those skilled in the art, and the specification is described in more detail with respect to particular applications. In an exemplary embodiment, the amount of nanocrystals loaded into the luminescent nanocrystal composition is on the order of about 10 volume percent to parts-per-million (ppm) level.

Luminescent nanocrystals for use in the present invention are suitably smaller in size than about 100 nm and down to levels smaller than about 2 nm. In a suitable embodiment, the luminescent nanocrystals of the present invention absorb visible light. As used herein, visible light is electromagnetic radiation having a wavelength between about 380 and about 780 nanometers that is visible to the human eye. Visible light can be separated into various colors on the spectrum, such as red, orange, yellow, green, blue, indigo, and violet. The photon-filtering nanocomposites of the present invention may be configured to absorb light constituting any one or more of these colors. For example, the nanocomposites of the present invention can be configured to absorb blue light, red light, or green light, a combination of these colors, or any colors in between. As used herein, blue light includes light between wavelengths of about 435 nm and about 500 nm, green light includes light between about 520 nm and 565 nm, and red light includes about 625 nm and about 740 nm. It includes light between. Those skilled in the art will be able to construct nanocomposites capable of filtering any combination of these wavelengths, or wavelengths between these colors, which nanocomposites are embodied by the present invention.

In another embodiment, the luminescent nanocrystals have a size and composition to absorb photons in the ultraviolet, near infrared, and / or infrared spectral regions. As used herein, the ultraviolet spectrum includes light between wavelengths of about 100 nm and about 400 nm, the near infrared spectrum includes light between about 750 nm and about 100 μm, and the infrared spectrum has a wavelength of about Light between 750 nm and about 300 μm.

In embodiments of the invention luminescent nanocrystals of any suitable material may be used, while in certain embodiments, the nanocrystals may be ZnS, InAs or CdSe nanocrystals, or the nanocrystals may be used in the practice of the invention. Various combinations can be included to form a population of nanocrystals for use. As mentioned above, in another embodiment, the luminescent nanocrystals are core / shell nanocrystals such as CdSe / ZnS, CdSe / CdS or InP / ZnS.

In order to hermetically seal the composition of the present invention, a barrier layer is disposed on the composition. For example, as shown in FIG. 1, the barrier layer 106 is disposed on a matrix 102 comprising luminescent nanocrystals 104, thereby producing a hermetically sealed composition. The term "barrier layer" is used to refer to a layer, coating, sealant, or other material disposed on the matrix 102 to hermetically seal the composition throughout the specification. Examples of barrier layers include layers, coatings, or materials of any material capable of producing an airtight seal on the composition. Suitable barrier layers include inorganic layers and suitably include inorganic oxides such as oxides of Al, Ba, Ca, Mg, Ni, Si, Ti or Zr. Exemplary inorganic oxide layers include SiO ₂ , TiO ₂ , AlO ₂ , and the like. As used throughout the specification, the terms "dispose" and "disposing" include any suitable method of applying a barrier layer. For example, placement includes layering, coating, spraying, sputtering, plasma enhanced chemical vapor deposition, atomic layer deposition, or other suitable method of applying the barrier layer to the composition. In suitable embodiments, sputtering is used to place the barrier layer on the composition. Sputtering involves a physical vapor deposition process using high energy ions to bombard an elemental source of material, thereby bouncing off vapors of atoms, and then depositing vapors in thin layers on the substrate. See, for example, US Pat. Nos. 6,541,790, 6,107,105, and 5,667,650, each disclosure of which is incorporated herein by reference in its entirety.

In yet another embodiment, disposing the barrier layer can be performed using atomic layer deposition. In applications such as coating of LEDs, luminescent nanocrystal compositions, such as nanocrystalline containing polymeric layers, can sometimes have complex geometries and features. For example, components of LEDs, such as bonding wires and solder joints, are sometimes in direct contact with or even contained within the polymeric layer. Suitably, in order to hermetically seal the nanocrystal composition, a practically flawless (ie, no pinhole) barrier layer is often needed. In addition, applying the barrier layer should not degrade the polymer or nanocrystals. Thus, in a suitable embodiment, atomic layer deposition is used to place the barrier layer.

Atomic Layer Deposition (ALD) may comprise deposition of an oxide layer (eg, TiO ₂ , SiO ₂ , AlO ₂ , etc.) on a luminescent nanocrystal composition, or in another embodiment, a nitride ( Deposition of a non-conductive layer such as, for example, silicon nitride) may be used. ALD deposits an atomic layer (ie, only a few molecules thick) by alternately supplying a reaction gas and a purging gas. Thin coatings can be formed having high aspect ratios, uniformity of depressions, and good electrical and physical properties. The barrier layer deposited by the ALD method is suitably low impurity density and thickness less than 1000 nm, suitably less than about 500 nm, less than about 200 nm, less than about 50 nm, less than about 20 nm Thickness, or thickness less than about 5 nm.

For example, in a suitable embodiment two reaction gases A and B are used. When only reaction gas A flows into the reaction chamber, atoms of reaction gas A are chemically adsorbed to the luminescent nanocrystal composition. Thereafter, any residual reaction gas A is purged with an inert gas such as argon or nitrogen. Thereafter, the reaction gas B is introduced, and a chemical reaction between the reaction gases A and B occurs only on the surface of the luminescent nanocrystal composition to which the reaction gas A is adsorbed, creating an atomic barrier layer on the composition.

In embodiments where a non-conductive layer, such as a nitride layer, is disposed, suitably, SiH ₂ Cl ₂ and remote plasma enhanced NH ₃ are used to place the silicon nitride layer. This can be done at low temperatures and does not require the use of reactive oxygen species.

Using ALD to deposit the barrier layer in the luminescent nanocrystal composition creates a barrier layer that is practically pinhole free regardless of the morphology of the substrate. By repeating the deposition step, the thickness of the barrier layer may be increased, thereby increasing the thickness of the layer in atomic layers according to the number of repetitions. In addition, the barrier layer may be further coated with additional layers (eg, via sputtering, CVD, or ALD) to protect or further strengthen the barrier.

Suitably, the ALD method utilized in the practice of the present invention is performed at a temperature below about 500 ° C., suitably below about 400 ° C., below about 300 ° C., or below about 200 ° C.

Exemplary barrier materials include organic materials that are specifically designed to reduce oxygen and moisture permeability. Examples include filled epoxy and liquid crystal polymers (such as alumina filled epoxy).

As described throughout the specification, the matrix 102 suitably includes a polymeric substrate. Accordingly, the present invention provides a composition comprising luminescent nanocrystals, suitably a polymer comprising luminescent nanocrystals, by disposing a barrier layer on the composition using any of the various methods known herein or in the art. A method of hermetically sealing a sexual substrate is included.

The ability to use a polymeric substrate as the matrix 102 allows for the formation of various shapes and configurations of the composition by simply molding or otherwise manipulating the composition in the desired shape / orientation. For example, a solution / suspension of luminescent nanocrystals (eg, luminescent nanocrystals in a polymeric matrix) can be prepared. This solution can then be placed in any desired mold to form the desired shape and then cured (eg, cooled or heated depending on the type of polymer) to form a solid or semi-solid structure. have . For example, the mold may be prepared in the form of a cap or disk to be placed on or above the LED. This then allows for the preparation of a composition which can be used, for example, as a downconversion layer. Subsequent to preparing the desired form, a barrier layer is then disposed on the composition to hermetically seal the composition, protecting the luminescent nanocrystals from oxidation.

In additional embodiments, compositions (eg, polymeric compositions) comprising luminescent nanocrystals directly may be placed directly on a desired substrate or article (eg, LED). Thereafter, after the luminescent nanocrystal composition (eg, a solution or suspension) is cured, a barrier layer can be placed on the composition to hermetically seal the composition directly onto the desired substrate or article. Thus, this embodiment does not require the preparation of a separate composition, but instead makes it possible to prepare the composition directly on the desired article / substrate (eg, a light source or other final product).

In yet another embodiment, the present invention provides a method for hermetically sealing a container comprising a plurality of luminescent nanocrystals. Suitably, the method includes providing a container, introducing luminescent nanocrystals into the container, and then sealing the container. For example, an exemplary method of hermetically sealing a container of luminescent nanocrystals is shown in the flowchart 200 of FIG. 2 with reference to FIGS. 3 and 4. In step 202 of FIG. 2, for example, a container such as the container 302 or 402 of FIGS. 3 and 4 is provided. As used herein, "container" refers to any suitable article or receptacle for holding nanocrystals. As used herein, it is to be understood that "vessel" comprising luminescent nanocrystals and "composition" comprising luminescent nanocrystals represent different embodiments of the present invention. A "composition" comprising luminescent nanocrystals refers to a matrix, such as a polymeric substrate, solution, or suspension, containing nanocrystals dispersed throughout. As used herein, "container" refers to a carrier, receptacle, or preformed article into which luminescent nanocrystals are introduced (sometimes a composition of luminescent nanocrystals, such as a polymeric matrix comprising luminescent nanocrystals). Examples of containers include, but are not limited to, polymeric or glass structures, such as tubes, molded or formed vessels, or receptacles. In an exemplary embodiment, the container may be formed by extruding the polymeric or glass material to a desired shape or similar structure, such as a tube (round, rectangular, triangular, elliptical, or other desired cross section). Any polymer may be used to form a container for use in the practice of the present invention, including throughout the specification. Exemplary polymers for the preparation of containers for use in the practice of the present invention include, but are not limited to, acrylics, poly (methylmethacrylate) (PMMA), and various silicone derivatives. Additional materials may also be used to form the container for use in the practice of the present invention. For example, the vessel can be prepared from metal, various glasses, ceramics, and the like.

For example, as shown in FIG. 2, once the container is provided in step 202, a plurality of luminescent nanocrystals 104 are introduced into the container in step 204. As used herein, "introduced" includes any suitable method of providing luminescent nanocrystals in a container. For example, luminescent nanocrystals can be injected into a container, located in a container, withdrawn into a container (eg, by using a suction or vacuum mechanism), or directed into the container, for example by using an electromagnetic field, Or other suitable method for introducing luminescent nanocrystals into a container. Suitably, luminescent nanocrystals are present in a solution or suspension, for example a polymeric solution, to aid in the introduction of the nanocrystals into the container. In an exemplary embodiment, the luminescent nanocrystals 104 may be introduced into a vessel, for example a vessel 302 in the form of a tube, as shown in FIG. 3. In another embodiment, as shown in FIG. 4, the container 402 can be prepared to have a cavity or cavity 404 into which the luminescent nanocrystals 104 can be introduced. For example, a solution of luminescent nanocrystals 104 can be introduced into the cavity 404 of the vessel 402.

Following introduction of luminescent nanocrystals into the container, the container is hermetically sealed at step 206, as shown in FIG. Examples of methods for hermetically sealing a container include, but are not limited to, heat sealing the container, ultrasonically welding the container, soldering the container, or adhesive bonding to the container. For example, as shown in FIG. 3, the container 302 can be sealed at any number of locations to produce various numbers of seals 304 throughout the container. In an exemplary embodiment, the container 302 may be heat sealed in various locations throughout the container, for example, by “pinching” the container after heating it at various sealing points 304.

In a suitable embodiment, as shown in FIG. 3, polymeric or glass tubes may be used as the vessel 302. Thereafter, a solution of luminescent nanocrystals 104 can be drawn to the vessel by applying a reduced pressure to the end of the vessel. The container 302 may then be sealed by heating and “pinching” the container in various sealing positions or seals 304 throughout the length of the container or by using other sealing mechanisms as described throughout the specification. . In this way, the container 302 can be separated into several individual sections 306. These sections can either be held together as a single sealed container 308, as shown in FIG. 3, or the sections can be separated into separate parts. Hermetic sealing of the container 302 can be performed such that each individual seal 304 separates solutions of the same nanocrystals. In other embodiments, the seal 304 can be created such that each of the separate sections of the container 302 includes a different nanocrystal solution (ie, different nanocrystal composition, size, or density).

In another embodiment, as shown in FIG. 4, luminescent nanocrystals can be placed into a cavity / cavity 404 formed in the vessel 402. The container 402 can be created using any suitable process. For example, the container 402 can be injection molded in any desired form or shape. The cavity / cavity 404 may be prepared for an initial preparation process (ie, during molding), or may be added subsequently after formation. Thereafter, luminescent nanocrystals 104 are introduced into the cavity / cavity 404. For example, luminescent nanocrystals may be injected or placed into the cavity / cavity 404 of the vessel 402. Suitably, the solution of luminescent nanocrystals fills the entire container, but it is not necessary to completely fill the container with nanocrystals. However, if the entire container is not filled, it is necessary to remove substantially all air in the container prior to sealing to ensure that the luminescent nanocrystals are hermetically sealed. As shown in FIG. 4, in an exemplary embodiment, the container 402 can be hermetically sealed by bonding, welding, or otherwise sealing the container with the cover or lid 406. Suitably, the cover 406 may be produced from the same material as the container 402 (and may be suitably partially attached prior to sealing), but may also include different materials. In additional embodiments, materials such as organic materials, especially designed to reduce oxygen and moisture permeability, may be used to cover or seal the container 402. Examples include filled epoxy (such as alumina filled epoxy) and liquid crystalline polymers.

For example, the ability to manufacture custom designed containers, such as by molding, extruding or molding the containers, allows for the preparation of highly specialized components in which luminescent nanocrystals can be introduced and hermetically sealed. To make it possible. For example, matching shapes can be generated around an LED or other light source (eg, for the purpose of piping down-conversion to another optical component). In addition, various films, disks, layers, and other forms may be prepared. In an exemplary embodiment, several different containers can be prepared, each of which can contain luminescent nanocrystals of different composition (ie, each composition emits a different color), and then the desired performance characteristics. Separate containers may be used together to produce this. In yet another embodiment, the container may be prepared to have a plurality of cavities or reservoirs into which luminescent nanocrystals can be introduced.

While the luminescent nanocrystals 104 may be hermetically sealed to the containers 302, 402 while in solution, suitably (eg, in step 210 of FIG. 2), the luminescent nanocrystal solution may be sealed prior to hermetic sealing. Cures. As used herein, "cured" refers to a process of hardening a solution of luminescent nanocrystals (eg, a polymeric solution). Curing can be accomplished by simply allowing the solution to dry and allowing any solvent to vaporize, or curing can be accomplished by heating or exposing the solution to light or other external energy. Following curing, the container can be hermetically sealed using various methods described throughout the specification.

In an exemplary embodiment, no additional hermetic sealing is required to protect the luminescent nanocrystals from oxidative degradation. For example, sealing the luminescent nanocrystals in a glass or polymeric container provides sufficient protection from oxygen and moisture so that no further modification is necessary. However, in another embodiment, an additional level of protection against oxidation can be added to the hermetically sealed container by placing a barrier layer on the container. For example, as shown in step 208 of FIG. As described throughout the specification, exemplary barrier layers include not only organic materials but also inorganic layers such as inorganic oxides such as SiO ₂ , TiO _2, and AlO ₂ . Any method of placing the barrier layer on the container may be used, while suitably, the barrier layer is sputtered on the container or disposed on the container via ALD. As shown in FIG. 3, the barrier layer 106 is disposed on a container with sealed sections, or on separate sections after sealing and separating from each other, to seal the hermetically sealed containers 310, 312. It can manufacture.

In a suitable embodiment of the invention, the various steps for producing a hermetically sealed container of luminescent nanocrystals are performed in an inert atmosphere. For example, steps 204, 206, and 208 (if required, step 210) are all suitably performed in an inert atmosphere, ie in vacuum and / or in the presence of only N ₂ or other inert gas (es). do.

In yet another embodiment, the present invention provides a container and a hermetically sealed composition comprising a plurality of luminescent nanocrystals. In an exemplary embodiment, the luminescent nanocrystals comprise one or more semiconductor materials (as described throughout the specification) and suitably comprise a core / such as CdSe / ZnS, CdSe / CdS or InP / ZnS. Shell luminescent nanocrystals. In general, luminescent nanocrystals are sizes of about 1 nm to 50 nm, suitably about 1 nm to 30 nm, more suitably about 1 nm to 10 nm, such as about 3 nm to 9 nm. In an exemplary embodiment, as described throughout the specification, the hermetically sealed composition and container of the present invention is a barrier layer that coats the composition (eg, a barrier layer 106 that coats the composition 100 of FIG. 1). )) And optionally a barrier layer for coating the container (eg, barrier layer 106 for coating the container 302 in FIG. 3). Exemplary barrier layers include inorganic layers such as SiO ₂ , TiO ₂ , and AlO ₂ , including those described throughout the specification.

In addition to creating various shapes, orientations, and sizes of the vessel for hermetically sealing the luminescent nanocrystals, further modifications may be made to the vessel / composition. For example, the container / composition may be prepared in the form of a lens for filtration or may include other light source changes. In yet another embodiment, the container / composition may be modified, for example by preparing or attaching a reflector or similar device to the container / composition.

In addition, the micropattern can be molded directly into the composition or container to form a flat (or curved) microlens. This can be done during the casting process or at a subsequent embossing step. When space is limitedly available, such as in displays, micropatterns may be utilized to achieve flat microlenses. Examples of such techniques include 3M's brightness enhancing films with 20-50 micron prisms molded on their surfaces. In a suitable embodiment, the present invention provides microlenses comprising luminescent nanocrystals that are hermetically sealed in (or in a container) encapsulated polymer and then micropatterned to form microlenses. For example, as shown in FIG. 5, the microlens assembly 500 is suitably positioned on top of the LED 506 supported by the substrate 508 or otherwise in contact with the LED 506. A hermetically sealed composition 502 comprising a layer 504 of nanocrystals 104. The surface of the composition 502 may be molded in various forms to form a microlens, including, for example, a series of microprisms 510 as shown in FIG. 5.

In an exemplary embodiment, the use of microlenses in combination with the hermetically sealed composition of the present invention allows to increase the amount of emitted light captured (and therefore emitted from the composition) from the LED / luminescent nanocrystals. For example, adding microprisms or other microlenses to the hermetically sealed compositions and containers of the present invention is suitably about as compared to compositions where the amount of light captured does not include microprisms or other microlens assemblies. Resulting in an increase of greater than 10% (eg, about 10% to 60%, about 10% to 50%, about 10% to 40%, about 20% to 40%, or about 30% to 40%). This increase in the amount of light captured is directly correlated with the increase in the total amount of light emitted from the composition or container.

In suitable embodiments, a dichroic mirror forming a lens for application to the light source can be attached or coupled to the container / composition. Dichroic mirrors allow light of a certain wavelength to pass through the mirror while others reflect it. As light from the light source enters the container / composition in the form of a lens, the photon can enter the container / composition and excite various luminescent nanocrystals that have been hermetically sealed inside. As the luminescent nanocrystals emit light, the photons can exit the container / composition, but cannot be reflected back toward the initial light source (since they are reflected by the dichroic mirror). In an embodiment, then, a suitable container / composition may be created to fit the light source (eg, LED). This allows light to enter from and excite the luminescent nanocrystals inside, but the emitted light is only allowed to exit the container / composition away from the light source, blocking it from being reflected back to the light source by the dichroic mirror do. For example, blue light from an LED light source passes through a dichroic mirror to excite encapsulated luminescent nanocrystals, which then emit green light. Green light is reflected by the mirror and is not allowed to reflect back to the light source.

As described herein, in a suitable embodiment, the hermetically sealed luminescent nanocrystal composition of the present invention is used in combination with an LED or other light source. The application of such sealed nanocrystals / LEDs is known to those skilled in the art and includes the following. For example, such sealed nanocrystals / LEDs can be found in microprojectors (see, eg, US Pat. Nos. 7,180,566 and 6,755,563, the disclosures of which are incorporated herein by reference in their entirety); Head-ups or heads for cellular phones, PDAs, personal media players (PMPs), gaming devices, laptops, digital versatile disk (DVD) players, and other video output devices, personal color eyewear, and automotive and aircraft It can be used in applications such as down (and other) displays. In additional embodiments, hermetically sealed nanocrystals can be used in applications such as Digital Light Processor (DLP) projectors.

In additional embodiments, hermetically sealed compositions and containers disclosed throughout the specification can be used to minimize the properties of the optical system known as etendue (or how diffuse light is in area or angle). have. Emitting nanocrystals with respect to the area (or thickness) of the LED by placing, stratifying, or otherwise covering (or even partially covering) the LED or other light source with the composition or container of the claimed invention. By controlling the proportion of the total area (or thickness) of the composition or container, the amount or range of etendue can be minimized to increase the amount of light captured and emitted. Suitably, the thickness of the luminescent nanocrystal composition or container is less than about 1/5 of the thickness of the LED layer. For example, the luminescent nanocrystal composition or container is less than about 1/6, less than about 1/7, less than about 1/8, less than about 1/9, or about 1 / of the thickness of the LED layer. Less than 10, less than about 1/15, or less than about 1/20.

In another embodiment, a system 602 comprising a light-focusing device (or focusing device) as shown in FIGS. 6A-6C, for example, hermetically sealed luminescent nanocrystals of the claimed invention. Can be used). In an exemplary embodiment, the light-focusing device 604 may be prepared with, attached to, and otherwise coupled with the LED 506. Suitably, the light-focusing device 604 is in the form of a cube or rectangular box, where the bottom of the box is located above or above the LED 506 and the side of the device extends above the LED. FIG. 6A shows a cross-sectional view of the device 604 taken through plane 1-1 of FIG. 6B, and FIG. 6B shows a top view of the device 604, the LED 506, and the substrate 508. In an exemplary embodiment, the device 604 includes four sides surrounding the LED 506, while in other embodiments, only a single piece of material (or multiple in a manner to form a continuous piece) Any number of sides (eg, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.) may be used, or a circular device, so that the pieces surround the LED 506). Can be used. In general, the top and bottom of the light-focusing device 604 are open (ie, the device is positioned directly above the LED 506 and surrounds the LED 506), in another embodiment, the device 604 The top or bottom of the rod, or both, can be closed by further pieces of material.

The focusing device 604 is suitably made of a material capable of reflecting light generated by the LED, or coated with a material that reflects light. For example, the focusing device may comprise a polymer, metal, ceramic, or the like. In other embodiments, the inner surface (ie, the surface facing the LED) may be coated with a reflective material, such as a metal (eg, Al) or other reflective coating. Such reflective coatings may be deposited on the surface of the focusing device using any suitable method such as spray coating, ALD, painting, dipping, spin coating, and the like.

The focusing device 604 suitably surrounds or encapsulates the hermetically sealed nanocrystal composition 504 (or hermetically sealed nanocrystal container) of the present invention, such that the device is associated with the composition or container. In a suitable embodiment, the focusing device 604 can be prepared separately from the LED 506, after which the central portion of the device 604 is hermetically sealed after being attached to the LED by an adhesive such as, for example, epoxy. Filled nanocrystalline composition 504. In yet another embodiment, the focusing device 604 may be assembled directly on the LED 506. In another embodiment, a hermetically sealed composition may be disposed on the LED, and then the focusing device may be added as a pre-made device or in a manner that is built directly on the LED. In a suitable embodiment, the device 604 also includes a cover (eg, a glass or polymer cover) to seal the nanocrystal composition 504. This cover serves as a hermetic seal over the nanocrystalline composition, or simply as an additional structural element for supporting the nanocrystalline composition and the focusing device. Such a cover may be located directly above the nanocrystalline composition 504 or may be located anywhere on or between the top of the device 604.

As shown in FIGS. 6A and 6C, in a suitable embodiment, the focusing device 604 is characterized in that the sides of the device are inward at the bottom (eg, near the LED), but outward at the top (away from the LED). Ready to taper. This helps to focus and focus the light 606 into a beam to direct light out of the device. As shown in FIG. 6C, suitably, the focusing device 604 directs the light 606 out of the LED. By using the tapered or angled side, the light 606 emitted from the LED / nanocrystals is not lost by simply bounced back and forth inside the device, or simply lost due to escape, but out of the device 604. Lose. The use of a light-focusing device in combination with the luminescent nanocrystal composition and container of the present invention can be suitably employed in microprojectors and other applications where a focus beam of light is required or desired.

Light Emitting Diode (LED) Device With Hermetically Sealed Nanocrystals

In a further embodiment, the present invention includes light emitting diode (LED) devices. An example LED device 700 is shown in FIG. 7A. LED device 700 suitably includes an LED 702. For illustrative purposes only, the LED 702 is shown on the substrate 706. It should be understood that any suitable configuration of LEDs may be used in the practice of the present invention. In addition, multiple (ie, more than one) LEDs can be used in the LED device 700. The LED device 700 also includes a hermetically sealed container 708 that includes a plurality of luminescent nanocrystals 710. The vessel 708 is optically connected to the LED 702. The LED device 700 also includes a light guide 712 optically coupled to the hermetically sealed container 708.

In embodiments of the invention, the first portion of the light emitted from the LED is down converted by the luminescent nanocrystals 710. The second portion of the light emitted from the LED and the down converted light from the luminescent nanocrystals are emitted from the light guide 712.

Any suitable LED is seen, including LEDs of various configurations, and LEDs that emit light over the entire visible spectrum, and LEDs that emit ultraviolet light (light having a wavelength of 10 nm to about 380 nm). It can be used in the LED devices of the invention. Suitably, LED 702 emits blue light. As described herein, the visible spectrum includes light having a wavelength between about 380 nm and about 780 nm that is visible to the human eye. Visible light can be separated into various colors of the spectrum such as red, orange, yellow, green, blue, indigo and purple. As used herein, blue light includes light between about 435 nm and about 500 nm, green light includes light between about 520 nm and 565 nm, more suitably between about 525 nm and about 530 nm, and red light. The silver wavelength includes light between about 625 nm and about 740 nm, more suitably between about 625 nm and about 640 nm.

Suitably, as shown in FIG. 7B, the LED 702 emits blue light 716. The first portion 718 of blue light emitted from the LED is down converted by the luminescent nanocrystals 710. As the nanocrystals absorb this portion of blue light, they emit light 722, 724 at a second wavelength (see FIG. 7B). Suitably, the light emitted from the nanocrystals 710 has a wavelength primarily of green (eg between about 520 nm and about 565 nm, more suitably between about 525 nm and about 530 nm) and red (eg For example, wavelengths between about 625 nm and about 740 nm, more suitably about 625 nm to about 640 nm). Thus, suitably the nanocrystals 710 comprise two groups of nanocrystals. One group of nanocrystals is designed to absorb blue light and emit red light, and the other group of nanocrystals are designed to absorb blue light and emit green light. The population of nanocrystals suitably includes a plurality of nanocrystals (ie, at least 2, at least 10, at least 100, at least 1000, etc.). As described herein, the ability to adjust the composition and size of nanocrystals allows the design of nanocrystals with specific absorption and emission characteristics.

The “first portion” 718 of blue light refers to the percentage of blue light 716 emitted from the LED that is down converted from blue to light of other wavelength (s). The first portion is any amount of original blue light emitted from the LED 702 that is less than the total amount of blue light emitted by the LED (eg, about 99% to about 1% of the blue light emitted from the LED 702, Suitably about 80% to about 30%, about 70% to about 40%, about 70% to about 50% or about 60%).

The second portion 720 of blue light emitted from the LED 702 passes through the hermetically sealed container 708 (suitably about 20% to about 50%, or about 20% to about 40%) blue light Appears. Next, down-converted light 722 and 724 (eg, red and green light) emitted from the second portion 720 of blue light and nanocrystals are emitted from the light guide 712 (726). Ultimately when emitted from the light guide, the blue light 720 emitted from the LED, and the down converted green light and red light 722 and 724 are suitably combined to produce white light 726.

In further embodiments, two (or more) blue light emitting LEDs are used such that all light from one (or more) LEDs can be downconverted by nanocrystals, while the second ( All light from the LED passes through the hermetically sealed container, resulting in red, green and blue wavelengths, which combine to produce white light.

Hermetically sealed container 708 is suitably a plastic or glass container. Exemplary hermetically sealed containers are described throughout. In a suitable embodiment, the hermetically sealed container is a plastic or glass (eg borosilicate) capillary. As described herein, “capillary” refers to an elongated container having a length dimension that is longer than the dimensions of both width and height. Suitably, the capillary is a tube or similar structure having a circular, rectangular, square, triangular, irregular, or other cross section. Suitably, the capillary for use in the LED devices of the present invention may be configured such that it matches the shape and orientation of the LED to which it is optically connected. In exemplary embodiments, the capillary has at least one dimension of about 100 μm to about 1 mm. In embodiments where plastic capillaries are used, coatings such as SiO ₂ , AlO ₂ or TiO ₂ and others described herein may be added to provide additional hermetic sealing to the capillary.

Suitably, the capillary of the present invention has a thickness of about 50 μm to about 10 mm, about 100 μm to about 1 mm, or about 100 μm to about 500 μm. Thickness refers to the dimension of the capillary into the plane of the light guide. Suitably, the capillary of the present invention has a height (in terms of light guide) of about 50 μm to about 10 mm, about 100 μm to about 1 mm, or about 100 μm to about 500 μm. Suitably, the capillary of the present invention (from the surface of the light guide) has a diameter of 1 mm to about 50 mm, about 1 mm to about 40 mm, about 1 mm to about 30 mm, about 1 mm to about 20 mm about 1 mm to It has a length of about 10 mm.

Also in further embodiments a hermetically sealed composition of luminescent nanocrystals can be used in LED devices as described herein. In such embodiments, the hermetically sealed composition is optically coupled to the LED and the light guide, thus providing down converted light from the nanocrystals.

As used herein, “light guide” refers to an optical component suitable for directing electromagnetic radiation (light) from one location to another. Exemplary light guides include fiber optic cables, polymeric or glass solids such as plates, films, containers or other structures. The size of the light guide will depend on the ultimate application and characteristics of the LED device. In general, the thickness of the light guide will be compatible with the thickness of the LED. Other dimensions of the light guide are generally designed to extend beyond the dimensions of the LED and suitably range from tens of millimeters to tens to hundreds of centimeters. The light guides illustrated in the figures indicate embodiments suitable for use in a display system and the like, but other light guides may also be used, including fiber optic cables and the like.

Exemplary nanocrystals for use in the practice of the invention are described herein. In some embodiments, the nanocrystals are core / shell nanocrystals. Suitably, the nanocrystals contain one or more ligands attached to the surface of the nanocrystals, which increase the solubility of the nanocrystals in the polymeric material. Exemplary ligands are described herein and in U.S. Patent Application No. 11 / 034,216, U.S. Patent Application Nos. 10 / 656,910 and U.S. Is described in patent application No. 60 / 578,236. Exemplary sizes of nanocrystals are also described herein.

In suitable embodiments, the luminescent nanocrystals comprise CdSe or ZnS. Exemplary core / shell nanocrystals that can be used include CdSe / ZnS, InP / ZnS, PbSe / PbS, CdSe / CdS, CdTe / CdS and CdTe / ZnS, nanocrystals. In exemplary embodiments, as described herein, nanocrystals are dispersed or embedded in a polymeric matrix. This matrix is then drawn into the capillary or otherwise placed in the capillary before sealing the capillary.

In further embodiments, scattering material (eg, particles of material that scatter light entering the hermetically sealed container) may be added to the matrix. Suitably the scattering media are metallic, polymeric, semiconducting or other material particles ranging in size from 500 nm to microns and even on the order of millimeters. In other embodiments, the scattering material may be located between the LED and the hermetically sealed container or between the container and the light guide.

The concentration of nanocrystals in a hermetically sealed container will depend on the application of nanocrystals, the size, the composition of the nanocrystals, the composition of the polymeric matrix and other factors and can be optimized using routine methods in the art. Can be. Suitably, the luminescent nanocrystals are about 0.01% to about 50%, about 0.1% to about 50%, about 1% to about 50%, about 1% to about 40%, about About 1% to about 30%, about 1% to about 20%, about 1% to about 10%, about 1% to about 5%, or about 1% to about 3% by weight Present in concentration. Suitably, about 40% to about 80%, more suitably about 50% to about 70%, or about 60% of the light from the LEDs is absorbed by the nanocrystals and the remaining light is suitably airtight. Pass through a sealed container. Suitably, about 10% to about 40%, or about 20% to about 30% of the light impinging on the container passes through the container without being downconverted.

As described herein, the hermetically sealed container 708 is optically connected to both the LED 702 and the light guide 712. As used herein, "optically coupled" means a component (eg, a hermetically sealed container and a container that allows light to pass through without substantial interference from one component to another). LED) is arranged. The optical connection may be such that the hermetically sealed container 708 and the LED 702 are in direct physical contact or the suitably hermetically sealed container 708 (and thus nanocrystals), as shown in FIG. 7A. 710) and the LEDs 702 are spaced apart at a distance 704. Although the hermetically sealed container 708 is shown in contact with the top of the substrate 706 in FIG. 7A, any suitable configuration, as long as light from the LED can pass through the hermetically sealed container 708. This can be used. For example, a hermetically sealed container may be disposed in the space between the top of the substrate 706 and the LED 702. In other embodiments, an optically transparent element (eg, a glass or plastic sheet or strip, including a lens) can be disposed between the hermetically sealed container 708 and the LED 704. It should be noted that the optical connection does not require physical interaction between the components. Rather, as long as light can pass between components, they are considered optically connected. Spacing between the hermetically sealed container 708 and the LED 702 results in the nanocrystals being placed remotely from the LED. This remote location improves the properties of light generated from LEDs and nanocrystals (intensity, purity, color rendering, etc.).

In embodiments, the light guide 712 is optically coupled to the hermetically sealed container 708 through adhesive, tape mechanical alignment alone or the like, and combinations thereof. As shown in FIG. 7A, the light guide 712 suitably makes direct contact with the hermetically sealed container 708. Tape, adhesive or other fastening device can be used to maintain physical contact between the two elements. Suitably the fastening device is optically transparent or substantially optically transparent, allowing light to pass from the hermetically sealed container to the light guide. This can also be accomplished, for example, by using a polymeric light guide that melts or deforms when heated so that the hermetically sealed container can contact the light guide, and then the light guide is cooled, Facilitate the formation of physical adhesion or contact between the dog elements.

8A-8C show additional configurations of the LED device described in FIG. 7A. In FIG. 8A, the light guide 712 is shown having a tapered edge 802. Tapered edge 802 may help to facilitate directing light emitted from LEDs and nanocrystals to light guide 712. In FIG. 8B, the hermetically sealed container 708 may be embedded into the light guide, as shown at 804. This can be accomplished, for example, by removing one section of the light guide 712 so that the hermetically sealed container can be inserted directly into the light guide 712. As mentioned above, in other embodiments, the light guide 712 is heated to melt or deform to allow the hermetically sealed container 708 to be inserted or embedded into the light guide 712. As illustrated in FIG. 8C, in further embodiments, the hermetically sealed container 708 may be shaped as shown at 806. In exemplary embodiments, the hermetically sealed container 708 can be shaped to act as a lens or other optical device to enhance light transmission from the LED to the light guide.

9 shows an embodiment of the LED device of the present invention, wherein the device comprises one or more reflectors 902 disposed against the LED, the light guide and the hermetically sealed container to increase the amount of light emitted from the light guide. It includes more. As shown in FIG. 9, in exemplary embodiments, the reflector reflects any light that is not directed to the light guide, or light bound back from the LED, emitted from nanocrystals in a hermetically sealed container. May be placed behind the LED. Likewise, the sides of the hermetically sealed container may also include a reflector 902 to reflect light towards the light guide. In further embodiments, the substrate on which the LED is disposed may also include reflective, angled sides that help direct light from the LED to the hermetically sealed container.

10A-10B provide an illustration of an exemplary hermetically sealed container 708, eg, a capillary tube. As shown in FIG. 10B, in embodiments, the end of the hermetically sealed container 708 (capillary) may be covered with a cap 1002. Cap 1002 is suitably made from a polymeric material that can be heated prior to application and then cooled to seal the hermetically sealed container. In other embodiments, the liquid polymeric solution can be used to fill the end of the hermetically sealed container to seal the container. Additional methods of sealing the hermetically sealed container, as described herein or otherwise known in the art, for example, crimping, pinching, laser sealing the end of the container Laser sealing, heat shrinking or otherwise closing may also be used.

Suitably, a solution of luminescent nanocrystals dispersed in the polymeric matrix is drawn out to the capillary by creating a reduced pressure, for example using a vacuum. The polymer is then suitably cooled and cured. The curing process can often result in small bubbles forming in the polymeric matrix. In these preparations small bubbles do not interfere with the optical properties of the nanocrystals or the composition, and in reality the presence of these small bubbles is when the matrix is thermally cycled during use or fabrication for the LED. It has been found that this may help to reduce the pressure that is escalating.

In suitable embodiments, the present invention provides white light emitting diode (LED) devices. Such devices suitably include a hermetically sealed container comprising a blue light emitting LED and a plurality of luminescent nanocrystals (suitably CdSe / ZnS luminescent nanocrystals) optically coupled to the LED. The device also includes a light guide optically coupled to the hermetically sealed container.

As illustrated in FIG. 7B, as the first portion 718 of blue light emitted from the LED enters the hermetically sealed container, the light is luminescent nanocrystals (eg, CdSe / ZnS luminescent nanocrystals). Are down converted to green light and red light 722 and 724. Second portion 720, green light and red light of blue light emitted from the LED are emitted from the light guide and combined to produce white light 726.

As described herein, the white light LED devices of the present invention include a hermetically sealed container that suitably includes luminescent nanocrystals spaced (remote) away from the LED. The concentration of nanocrystals in the hermetically sealed container is provided so that a portion of the blue light emitted by the LED can pass through the container without being absorbed by the nanocrystals. Another portion of the blue light is absorbed, then downconverted by the nanocrystals and emitted as green and red light. The red light, blue light and green light then combine to produce white light when emitted from the light guide. The approach of the present invention is different from white light LEDs in which three separate light sources (eg three LEDs) are used, or in which all blue light from the LED is absorbed by the luminescent nanocrystals. By optimizing the concentration / density and properties of the nanocrystals, high intensity, high purity, precisely color adjusted, white light can be produced.

In further embodiments, the present invention provides a light emitting diode comprising an LED, a hermetically sealed container comprising a plurality of luminescent nanocrystals optically connected to the LED, and a light guide optically connected to the hermetically sealed container ( LED) devices. Light emitted from the LED is down converted by the nanocrystals and exits the surface of the light guide. Suitably, the luminescent nanocrystals emit blue light, green light and red light and the light combines to produce white light. In such embodiments, the LED suitably emits ultraviolet light.

In further embodiments, the present invention provides display systems comprising the LED devices described herein. Suitably, as shown in FIG. 11, display system 1100 includes a display 1102 and a plurality of LED devices 700. As described herein, the LED devices 700 suitably include an LED 702 and a hermetically sealed container 708 that includes a plurality of luminescent nanocrystals optically coupled to the LED. The devices also include a light guide 712 optically coupled to the hermetically sealed container. As shown in FIG. 11, suitably, the display 1102 at least partially surrounds the light guide 712.

In embodiments, the down converted light emitted from the luminescent nanocrystals is emitted from the light guide and displayed on the display. Display systems of the present invention can emit light over the entire range of the visible spectrum, including white light.

In further embodiments, the first portion of light emitted from the LED is down converted by luminescent nanocrystals. The second portion of the light emitted from the LED and the down converted light from the luminescent nanocrystals are emitted from the light guide and displayed on the display. Display systems of the present invention can emit light over the entire range of the visible spectrum, including white light. In exemplary embodiments, the LEDs emit blue light.

 Exemplary hermetically sealed containers (including capillaries) and luminescent nanocrystals are described herein. As shown in FIG. 11, suitably a single hermetically sealed container 708 ′ is optically connected to at least two LEDs. A single hermetically sealed container may be optically connected to two or more, three or more, four or more, five or more, 10 or more LEDs. The hermetically sealed container 708 can be connected to each individual LED, but in the display system embodiments of the present invention, the use of a single hermetically sealed container connected to multiple LEDs allows for easier assembly and Allow manufacturing. In embodiments in which a single hermetically sealed container is connected to multiple LEDs, each LED suitably emits blue light, some of which is downwardly transformed by nanocrystals in the container, some of which are emitted from the light guide. do. Although FIG. 11 describes an embodiment in which a single light guide and a single display are used, the display systems of the present invention can include a plurality of light guides and multiple displays optically coupled to one another, resulting in a display system.

Hermetically sealed containers containing luminescent nanocrystals as described herein can be used to retrofit existing LED display systems. By including a hermetically sealed container (eg, a capillary tube) between the LED of the display and the light guide, some light from the LED (preferably blue light) is combined with the LED light to produce white light. Can be converted to any desired color.

Table 1 below shows the light output from the luminescent nanocrystals of the present invention and the light from the blue LED used to excite the nanocrystals. Nanocrystals are spaced from the LED (remote from the LED) as described herein. Also shown are data for a traditional Yttrium Aluminum Garnet (YAG) phosphor. FWHM = full width at half maximum

Spectral characteristics YAG Luminescent Nanocrystals Blue peak (nm) 451.8 463.5 Blue FWHM (nm) 21.6 21.6 Green peak (nm) N / A 535.3 Green FWHM (nm) N / A 32.8 Orange peak (nm) 559 N / A Orange FWHM (nm) 105 N / A Red peak (nm) N / A 614.5 Red FWHM (nm) N / A 44.5

Luminescent Nanocrystalline Composites

In yet another embodiment, the present invention provides a luminescent nanocrystal composite material 1200. As shown in FIG. 12, in embodiments, the composite material includes a first polymeric material 1204 including a first composition, a second polymeric material 1202 comprising a second composition, and a second polymeric material And a plurality of luminescent nanocrystals 710 dispersed at 1202. The second polymeric material 1202 is dispersed in the first polymeric material 1204.

Dispersing the luminescent nanocrystals in the second polymeric material 1202 provides a method of sealing the nanocrystals and provides a mechanism for mixing the various compositions and sizes of the nanocrystals. Suitable second polymeric material 1202 includes aminosilicone, and other polymers described herein, including but not limited to poly (vinyl butyral): poly (vinyl acetate); Epoxy; urethane; Silicones and derivatives of silicones including, but not limited to, polyphenylmethylsiloxanes, polyphenylalkylsiloxanes, polydiphenylsiloxanes, polydialkylsiloxanes, silicone fluorides and vinyl and hydride substituted silicones; Acrylic polymers and copolymers formed from monomers including but not limited to methylmethacrylate, butylmethacrylate and lauryl methacrylate; Styrenic polymers; And polymers crosslinked with bifunctional monomers such as divinylbenzene.

The second polymeric material 1202 provides a suitable environment for dispersing nanocrystals, but polymers that provide effective mixing of nanocrystals can often be brittle or difficult to mold or mold. Dispersing nanocrystals / polymer mixture 1202 in additional polymeric material 1204 maintains the desired optical / downconversion properties of the luminescent nanocrystals, while also providing a hermetically sealed composition that can be machined as desired. Allow the manufacture of composites to retain. Exemplary polymeric materials for use as the first polymeric material 1204 include epoxy and polycarbonate. Exemplary epoxies and polycarbonates are well known in the art.

Suitably, the luminescent nanocrystals dispersed in the composite material absorb light (eg, blue light) and emit green light and / or red light, but other colors may also be emitted from the nanocrystals. Exemplary nanocrystals for use in the composite material are described herein, nanocrystals comprising CdSe or ZnS and CdSe / ZnS, InP / ZnS, PbSe / PbS, CdSe / CdS, CdTe / CdS or CdTe Core / shell luminescent nanocrystals comprising / ZnS.

In further embodiments, the composite can include an inorganic layer 1206 that hermetically seals the composite. Examples of inorganic layers are described herein and include SiO ₂ , TiO ₂ or AlO ₂ .

Suitably, the composite material of the present invention has an optical density of about 0.5 to about 0.9 and a path length of about 50 μm to about 200 μm at a blue LED wavelength. Suitably, the composite has an optical density of about 0.5 to about 0.8, about 0.7 to about 0.8, or about 0.8 at a blue LED wavelength. Suitably, the path length of the composite material is from about 75 μm to about 150 μm, or about 100 μm. The concentration of luminescent nanocrystals used in the composite material of the present invention is suitably about the same as the concentration used in the hermetically sealed compositions described herein. Thus, the luminescent nanocrystals suitably range from about 0.01% to about 50%, from about 0.1% to about 50%, from about 1% to about 50%, from about 1% to about 40%, About 1% to about 30%, about 1% to about 20%, about 1% to about 10%, about 1% to about 5%, or about 1% to about 3% At a concentration of about 40% to about 80%, more suitably about 50% to about 70%, or about 60% of the light impinging on the composite is absorbed by the nanocrystals.

The present invention also provides methods for producing luminescent nanocrystal composite materials. As shown in flowchart 1300 of FIG. 13, with reference to FIG. 12, such methods suitably include a plurality of luminescent nanocrystals (eg, to form a mixture of luminescent nanocrystals and a first polymeric material). 710 includes dispersing 710 into the first polymeric material 1202. The mixture is then cured at 1304. At 1308, particles are produced from the cured mixture. In step 1310, the particles are dispersed in the second polymeric material 1204 to produce a composite material. The particles can be dispersed in the second polymeric material using various forms of mechanical mixing when the second polymeric material is in the liquid state, or primarily in the liquid state.

Exemplary polymeric materials for use in the methods are described herein, which are suitable luminescent nanocrystals. Suitably, the luminescent nanocrystals are core / shell nanocrystals comprising CdSe or ZnS or comprising CdSe / ZnS, InP / ZnS, PbSe / PbS, CdSe / CdS, CdTe / CdS or CdTe / ZnS, Suitably dispersed in aminosilicon.

Suitably the mixture of luminescent nanocrystals and the first polymeric material is mechanically processed to form the particles. Examples of mechanical processing include forming particles from a mixture by ball milling, grinding, pulverizing, crushing or other methods. Chemical or other treatments may also be used to produce the particles. Suitably, the particles are powders. Suitably, the particles of the mixture of nanocrystals and the first polymeric material may be from about 10 μm to about 200 μm, or from about 10 μm to about 100 μm, or from about 20 μm to about 70 μm, or about 50 μm Has a size.

In addition to the particles, other structures of the mixture of luminescent nanocrystals and the first polymeric material may also be produced, such as films, rods, ribbons, spheres and the like. These structures can then be dispersed in the second polymeric material.

In further embodiments, the second polymeric material may be replaced with other materials, such as ceramic, glass, or other inorganic material, such as having the desired optical and physical properties of the final desired product.

In exemplary embodiments, the crosslinker is added to the mixture at step 1306 before curing at 1304. Exemplary crosslinkers are described herein or otherwise known in the art.

In further embodiments, as shown in FIG. 13, the methods can further include a step 1312 of forming the composite material into a film. Suitably, the composite material is for example, a casting (casting) on a substrate such as a non-adhesive substrate (non-stick substrate) such as a sheet of TEFLON ^®. After the mixture has cured, the cured film can be removed from the non-adhesive substrate. Next, the film can be cut or diced into any desired size or shape.

In further embodiments, an inorganic layer can be disposed on the composite to provide additional hermetic sealing to the composite, as shown in step 1314 of flowchart 1300. The inorganic layer may be disposed after the composite material is formed but before forming the composite into the film, or the inorganic layer may be disposed after film formation (including dicing / cutting into the desired shape). Methods of placing an inorganic layer in a composite are described herein and include various methods such as coating, spraying, ALD, dipping, and the like.

The composite material can also form composites of the desired shape and configuration by extruding, molding, solvent casting, compression molding, and the like. Methods and parameters for performing these techniques are well known in the art.

The composite material of the present invention can be used in the downconversion applications described herein or in other applications where a downconversion layer / film / structure is desired. Thus, in exemplary embodiments, a layer, film, tube, strip or other suitable structure is prepared from the composite material and optically connected to the LED (and / or light guide) to direct the light from the LED as described herein. You can provide a transformation.

Light Guide Nanocrystals Including Nanocrystals

In yet another embodiment, the present invention provides light emitting diode (LED) devices as shown in FIGS. 14A-14B. Suitably, the LED devices 1400 and 1401 include an LED 702 and a light guide 712 optically coupled to the LED. A plurality of luminescent nanocrystals 710 are dispersed in regions 1404, 1404 ′ in the light guide. Suitably, the region extends along the length 1410 of the light guide. Suitably, the nanocrystals emit blue light, red light and green light. In embodiments, the LED is an ultraviolet (UV) emitting LED.

In further embodiments, the first portion of light emitted from the LED is down converted by nanocrystals. As shown in FIGS. 14A and 14B, the second portion 1412 and down-converted light 1414 and 1416 of the light emitted from the LED exit the surface of the light guide.

As will be explained, the luminescent nanocrystals of the present invention suitably absorb light of a particular wavelength and then down convert the absorbed light and emit light of different wavelengths. In the embodiments of the invention illustrated in FIGS. 14A-14B, luminescent nanocrystals 710 are dispersed in regions 1404 and 1404 ′ of the light guide. Light emitted from the LED travels through the length of the light guide 1410 and suitably reflects off the reflectors along the surface of the light guide. In embodiments, a portion of the light emitted from the LED is emitted from the surface of the light guide as shown at 1412. Another portion of the light emitted from the light guide is absorbed and downconverted by the luminescent nanocrystals. This down-converted light 1414 and 1416 are then emitted from the light guide. In further embodiments, all light emitted from the LED is down converted by the nanocrystals.

In exemplary embodiments, the LED is a blue light emitting LED. As described in detail herein, in exemplary embodiments, a portion of the blue light emitted from the LED is down converted to red and green light by luminescent nanocrystals. When the emitted green light 1414 and red light 1416 combine with the portion 1412 of blue light emitted from the (not down-converted) LED, white light is emitted from the surface of the light guide. In suitable embodiments, the light guide 712 includes one or more features 1406 on the emitting surface (s) of the light guide. The features 1406 are suitably patterns etched or formed from the surface of the light guide 712, which aids in the transmission of light from the light guide. In embodiments, features 1406 are designed to enhance the emission of light emitted directly from the LED (including blue light).

In further embodiments, the LED is a UV emitting LED and substantially all light emitted from the LED is down converted to red, green and blue light by nanocrystals. The light is then emitted from the light guide and combined to produce white light.

Exemplary nanocrystals for use in the regions within the light guides are described herein. Suitably, the nanocrystals comprise CdSe or ZnS, or suitably core / shell nanocrystals comprising CdSe / ZnS, InP / ZnS, PbSe / PbS, CdSe / CdS, CdTe / CdS or CdTe / ZnS admit.

As used herein, “region” refers to one section or portion of the light guide in which the luminescent nanocrystals are disposed. Suitably, as shown in FIGS. 14A-14B, regions 1404 and 1404 ′ extend along length 1410 of light guide 712. The length 1410 of the light guide is a transverse dimension extending perpendicular to (or substantially perpendicular to) the LED. By orienting the light guide 712 with respect to the LED 702 as shown in FIGS. 14A and 14B, the light from the LED 702 is in the areas 1404 and 1404 ′ before exiting the light guide. It collides with more parts of the nanocrystals. Suitably, region 1404/1404 'is a layer of luminescent nanocrystals. The dimensions of the region 1404/1404 'are governed by the overall dimensions of the light guide, but in general the thickness of the region is proportional to the size of the LED (i.e., on the order of tens of microns to tens of millimeters), while the plane of the light guide The dimensions (ie, length and width) suitably span the entire light guide. In other embodiments, the region comprising nanocrystals may span the entire light guide in all dimensions (ie, may be dispersed throughout the light guide).

Region 1404/1404 'can be created by dispersing nanocrystals in a polymeric matrix and then forming a light guide around the polymer either before or after curing the polymer. Alternatively, the light guide may be prepared and then the nanocrystals may be deposited, implanted, painted, sprayed or otherwise deposited to form a region. Other methods for producing polymeric materials can also be used to form regions, including the methods described herein with respect to the formation of polymeric composites. In exemplary embodiments, the luminescent nanocrystal composite material 1200 described herein can be used to prepare regions in the light guide.

Dispersing luminescent nanocrystals in areas within the light guide provides many benefits and advantages to the overall system. For example, more uniform illumination of nanocrystals can be achieved, reducing the presence of local hot spots. Dispersing nanocrystals throughout the region allows for improved heat dissipation from the nanocrystals, lowering the overall temperature of the nanocrystals. By reducing the light path length from the nanocrystals to the top side of the light guide, the loss of efficiency due to reabsorption of green and red photons is reduced. In addition, low concentrations of nanocrystals are used in the region, thus reducing the possible photon- and heat-induced interactions between the nanocrystals and the material (eg, the polymer) in which the nanocrystals are dispersed, thereby increasing system life. Can be.

The concentration of luminescent nanocrystals in the region of the light guide will depend on the application of the nanocrystals, the size, the composition of the nanocrystals, the composition of the polymeric matrix and other factors and can be optimized using routine methods in the art. Can be. Suitably, the luminescent nanocrystals are suitably about 0.01% to about 50%, about 0.1% to about 50%, about 1% to about 50%, more suitably about 1% by weight. To about 40%, about 1% to about 30%, about 1% to about 20%, about 1% to about 10%, about 1% to about 5%, or about 1% At a concentration of from about 3% to about 3% by weight, the concentration is less than the concentration used in the LED device embodiments described herein using a hermetically sealed container. In general, the concentration of luminescent nanocrystals is scaled proportionally based on the size of the light guide. Thus, the concentration of luminescent nanocrystals used in a hermetically sealed container having a thickness of approximately 100 mm will be reduced by 2 orders of magnitude compared to, for example, a light guide about 10 cm long.

In exemplary embodiments, the region 1404 ′ has a thickness that varies along the length 1410 of the light guide. As shown in FIG. 14B, the thickness of the region 1404 ′ suitably is along the length 1410 of the light guide, away from the minimum value 1406 in the LED, away from the LED, the far end of the light guide 1408. Increases to the maximum at In exemplary embodiments, the thickness increases approximately linearly along the length of the light guide. In further embodiments, the thickness may increase in a non-linear manner and / or achieve a maximum thickness before reaching the original end of the light guide 1408. The schematic diagram shown in FIG. 14B showing the thickness of the region 1404 ′ increasing linearly along both the top and bottom of the region is for illustrative purposes only and the region 1404 ′ of any suitable shape / orientation. It should be noted that this can be used. Changing the thickness of the area provides more uniform light illumination from the light guide.

15 (a) -15 (c) show the intensity of light emitted from the light guide shown in FIG. 14a. The intensity is shown as a function of relative distance, starting at zero (0), adjacent to the LED 1406, along the light guide, to the far end 1408, day 1 of the light guide, away from the LED. . Figure 15 (a) shows the intensity of blue light reflected in the light guide before being emitted as well as emitted (going forward) from the LED. Figure 15 (b) shows the intensity of green and red light emitted from nanocrystals, obtained from both blue light reflected directly from the LED as well as reflected blue light. Finally, FIG. 15C illustrates a plot of intensity showing the combined sum of all blue light emitted from the light guide (sum of blue) and the combined sum of all green and red light (sum of green / red). . As shown in Fig. 15 (c), the intensity of the blue light and the green / red light is weakened along the length of the light guide. Blue light is weakened as a result of absorption over the length of the light guide. Since the amount of nanocrystals in the region of the light guide is constant (due to the uniform thickness of the region), the intensity of the red and green light is also reduced along the length of the light guide.

Figures 16 (a)-16 (c) are figures 15 (a)-15 (c) except for the light guide configuration (region 1404 'with nanocrystals with varying thickness) illustrated in Figure 14b. Show an intensity plot similar to the ones in. In addition to moving forward, the amount of emitted blue light reflected is similar to a constant thickness region. However, when comparing the intensity of the green light / red light in Figs. 16 (b)-16 (c) with Figs. 15 (b)-15 (c), the thickness 1404 'of which the green / red light of better uniformity changes. It can be seen that it is emitted from a light guide having an area with. This is likely a result of increased thickness of the area 1404 'at the end of the light guide away from the LED. As there are more nanocrystals at the far end of the light guide (although the concentration can be consistent across the lightguide), more blue light can be absorbed and downconverted to green and red light.

The invention also provides display systems comprising a display, a plurality of LEDs and a light guide optically coupled to the LEDs, the display at least partially surrounding the light guide. As described herein, a plurality of nanocrystals are dispersed in a region inside the light guide, which region extends along the length of the light guide. Light from the LED is down converted by the nanocrystals, exits the light guide, and displayed on the display. In embodiments, the LED is a UV emitting LED and the nanocrystals emit red light, green light and blue light.

In other embodiments, the first portion of light emitted from the LED is down converted by the luminescent nanocrystals, and the second portion of light emitted from the LED, and the down converted light from the luminescent nanocrystals is emitted from the light guide. And displayed on the display. As described herein, in the exemplary embodiments the LED emits blue light, and the first portion of the blue light emitted from the LED is down converted to green and red light by the luminescent nanocrystals. Suitably, the second portion of blue light, green light and red light are combined to produce white light.

Exemplary nanocrystals are described herein, including core shell nanocrystals. In exemplary embodiments, the light guide includes one or more reflectors.

Suitably, the region containing luminescent nanocrystals is a layer of nanocrystals. In exemplary embodiments, the thickness of the region varies along the length of the light guide and increases, for example, linearly, along the length of the light guide, suitably from the LED, as described herein.

Yes

The following examples are illustrative of the methods and compositions of the present invention, but are not limited to these. Other suitable changes and adaptations of various conditions and parameters will normally be encountered in nanocrystal synthesis, which will be apparent to those skilled in the art and are within the spirit and scope of the present invention.

Example 1

Preparation of hermetically sealed containers

An approximately 3 mm by 0.5 mm rectangular tube with a 2 mm by 0.5 mm cavity is prepared by extrusion of the PMMA. The length of the tubing is then filled with a solution containing fluorescent luminescent nanocrystals. The luminescent nanocrystal solution is then cured. Segments of the tubing are then heat sealed to trap the nanocrystals of the tubing. Suitably, filling and sealing are performed in an inert atmosphere. A barrier layer (eg SiO ₂ , TiO ₂ or AlO ₂ ) can then be disposed on the outer surface of the tubing.

Drawn glass capillary can also be used to prepare a hermetically sealed container containing nanocrystals. The end of the capillary is sealed either by melt sealing or by soldering or plugging with an adhesive or similar structure. The capillary can be filled with a solution of luminescent nanocrystals such that the entire volume of the capillary is filled with the same nanocrystal solution, or the capillary can be filled in stages so that different nanocrystals separate along the length of the capillary. For example, after the first luminescent nanocrystal solution is introduced into the capillary, a seal can be placed adjacent to the solution (eg, melt sealing or plugging the capillary). Thereafter, a second luminescent nanocrystal solution can be added to the capillary and again the seal is placed near the solution. This process can be repeated as desired until the desired number of individual hermetically sealed nanocrystal segments is produced. In this manner, luminescent nanocrystals of different composition may be separated from each other in the same vessel, to enable the manufacture of a vessel comprising luminescent nanocrystals of multiple compositions (eg, colors). In a similar embodiment, multi-lumens of different compositions of luminescent nanocrystals (eg those emitting different colors) are introduced and separated from each other, which can still be hermetically sealed from outside air and moisture. Capillary can be used.

Example 2

Preparation of Nanocrystalline Composites

Luminescent nanocrystals (eg, CdSe / ZnS) that emit red light (630 nm) and green light (530 nm) are mixed in an aminosilicone polymer at a concentration of 3% by weight. The aminosilicone polymer has a viscosity of 350 centipoise and comprises 5% amino groups and 95% dimethylsiloxane. The resulting composition has an optical density of about 0.8 and a path length of 100 μm.

An epoxide crosslinker is added and the material cures to form a rubber. The cured quantum dot composition is then placed in a ball mill and ground to a 50 μm powder.

The powder is then mixed into a two part epoxy at about 30% loading and the polymer is degassed. The refractive indices of the nanocrystals and the epoxy are suitably matched to minimize light scattering and the resulting absorption by the nanocrystals.

The epoxy / nanocrystal mixture is cast on a TEFLON ^® sheet about 300 μm thick. After curing, the film is removed. The optical density of the final composite material is about 0.8 OD.

Exemplary embodiments of the invention have been provided. The invention is not limited to these examples. Such examples are provided herein for purposes of illustration, but are not limited to these. Alternatives (including equivalents, expansions, modifications, deviations, etc. of those described herein) will be apparent to those skilled in the art based on the teachings contained herein. Such alternatives fall within the scope and spirit of the present invention.

All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent if each individual publication, patent, or patent application is specifically and individually indicated to be incorporated by reference. .

Claims (114)

As a light emitting diode (LED) device,
(a) a blue light emitting LED; And
(b) a hermetically sealed container comprising a plurality of luminescent nanocrystals,
Wherein the vessel is disposed relative to the LED to facilitate down conversion of the luminescent nanocrystals. The method of claim 1,
The hermetically sealed container is a plastic tube or glass tube. The method of claim 1,
The hermetically sealed container is a glass capillary. The method of claim 1,
The hermetically sealed container is spaced apart from the LED. The method of claim 1,
The luminescent nanocrystals emit green light and red light. The method of claim 1,
Wherein the luminescent nanocrystals comprise CdSe or ZnS. The method of claim 1,
The luminescent nanocrystals are core / shell luminescent nanocrystals comprising CdSe / ZnS, InP / ZnS, PbSe / PbS, CdSe / CdS, CdTe / CdS or CdTe / ZnS. The method of claim 1,
Wherein the luminescent nanocrystals are dispersed in a polymeric matrix. As a display system,
(a) a display; And
(b) a plurality of light emitting diode (LED) devices, wherein the LED devices are:
(i) blue light emitting LEDs; And
(ii) a hermetically sealed container comprising a plurality of luminescent nanocrystals, the container being disposed relative to the LED to facilitate down conversion of the luminescent nanocrystals. The method of claim 9,
And the hermetically sealed container is a plastic tube or a glass tube. The method of claim 9,
And the hermetically sealed container is a glass capillary. The method of claim 9,
And the hermetically sealed container is spaced apart from the LED. The method of claim 9,
Wherein the luminescent nanocrystals emit green light and red light. The method of claim 9,
Wherein the luminescent nanocrystals comprise CdSe or ZnS. The method of claim 9,
The luminescent nanocrystals are core / shell luminescent nanocrystals comprising CdSe / ZnS, InP / ZnS, PbSe / PbS, CdSe / CdS, CdTe / CdS or CdTe / ZnS. The method of claim 9,
Wherein the luminescent nanocrystals are dispersed in a polymeric matrix. As a light emitting diode (LED) device,
(a) an LED;
(b) a hermetically sealed container comprising a plurality of luminescent nanocrystals optically coupled to the LED; And
(c) a light guide optically coupled to the hermetically sealed container,
Wherein the first portion of light emitted from the LED is down converted by the luminescent nanocrystals, and the second portion of light emitted from the LED and light down converted from the luminescent nanocrystals is emitted from the light guide. Diode (LED) device. The method of claim 17,
Wherein the LED emits blue light. The method of claim 18,
Wherein the first portion of blue light emitted from the LED is down converted to green and red light by the light emitting nanocrystals. The method of claim 19,
And a second portion of the blue light, the green light and the red light combine to produce white light. The method of claim 17,
The hermetically sealed container is a plastic container or a glass container. 22. The method of claim 21,
The hermetically sealed container is a glass capillary. The method of claim 22,
Wherein the glass capillary has at least one dimension of about 100 μm to about 1 mm. The method of claim 17,
Wherein the luminescent nanocrystals comprise CdSe or ZnS. The method of claim 17,
The luminescent nanocrystals are core / shell nanocrystals comprising CdSe / ZnS, InP / ZnS, PbSe / PbS, CdSe / CdS, CdTe / CdS or CdTe / ZnS. The method of claim 17,
Wherein the light guide is optically coupled to the hermetically sealed container via an adhesive or tape. The method of claim 17,
The hermetically sealed container is spaced apart from the LED. The method of claim 17,
Wherein the luminescent nanocrystals are dispersed in a polymeric matrix. White light emitting diode (LED) device,
(a) a blue light emitting LED;
(b) a hermetically sealed container comprising a plurality of CdSe / ZnS luminescent nanocrystals optically coupled to the LED; And
(c) a light guide optically coupled to the hermetically sealed container,
The first portion of blue light emitted from the LED is down converted to green light and red light by the CdSe / ZnS luminescent nanocrystals, and the second portion of blue light emitted from the LED, the green light and the red light are from the light guide. A white light emitting diode (LED) device, wherein the light is emitted and combined to produce white light. 30. The method of claim 29,
The hermetically sealed container is a plastic container or a glass container. 31. The method of claim 30,
The hermetically sealed container is a glass capillary. The method of claim 31, wherein
And the glass capillary has at least one dimension of about 100 μm to about 1 mm. 30. The method of claim 29,
And the light guide is optically connected to the hermetically sealed container via an adhesive or tape. 30. The method of claim 29,
And the hermetically sealed container is spaced apart from the LED. 30. The method of claim 29,
The CdSe / ZnS luminescent nanocrystals are dispersed in a polymeric matrix. As a display system,
(a) a display;
(b) a plurality of light emitting diode (LED) devices, wherein the LED devices are:
(i) an LED; And
(ii) the plurality of light emitting diode (LED) devices comprising a hermetically sealed container comprising a plurality of luminescent nanocrystals optically coupled to the LED; And
(c) a light guide optically coupled to the hermetically sealed container, the light guide at least partially surrounded by the display,
The first portion of light emitted from the LED is down converted by the light emitting nanocrystals, and the second portion of light emitted from the LED and light down converted from the light emitting nanocrystals is emitted from the light guide and the display A display system displayed on the display. The method of claim 36,
And the LED emits blue light. 39. The method of claim 37,
And a first portion of blue light emitted from the LED is down converted to green light and red light by the light emitting nanocrystals. The method of claim 38,
And the second portion of the blue light, the green light and the red light combine to produce white light. The method of claim 36,
And the hermetically sealed container is a plastic container or a glass container. 41. The method of claim 40,
And the hermetically sealed container is a glass capillary. 42. The method of claim 41,
And the glass capillary tube has at least one dimension of about 100 μm to about 1 mm. The method of claim 36,
Wherein the luminescent nanocrystals comprise CdSe or ZnS. The method of claim 36,
The luminescent nanocrystals are core / shell luminescent nanocrystals comprising CdSe / ZnS, InP / ZnS, PbSe / PbS, CdSe / CdS, CdTe / CdS or CdTe / ZnS. The method of claim 36,
And the light guide is optically connected to the hermetically sealed container via adhesive or tape. The method of claim 36,
And the hermetically sealed container is optically connected to at least two LEDs. The method of claim 36,
Wherein the luminescent nanocrystals are dispersed in a polymeric matrix. As a composite material:
(a) a first polymeric material having a first composition;
(b) a second polymeric material having a second composition; And
(c) a plurality of luminescent nanocrystals dispersed in said second polymeric material,
And the second polymeric material is dispersed in the first polymeric material. 49. The method of claim 48,
Wherein the first polymeric material comprises epoxy or polycarbonate. 49. The method of claim 48,
And the second polymeric material comprises aminosilicon. 49. The method of claim 48,
The luminescent nanocrystals emit green light and / or red light. 49. The method of claim 48,
The luminescent nanocrystals comprise CdSe or ZnS. 49. The method of claim 48,
The luminescent nanocrystals are core / shell luminescent nanocrystals comprising CdSe / ZnS, InP / ZnS, PbSe / PbS, CdSe / CdS, CdTe / CdS or CdTe / ZnS. 49. The method of claim 48,
The composite material further comprising an inorganic layer of SiO ₂ , TiO ₂ or AlO ₂ hermetically sealing the composite material. 49. The method of claim 48,
Wherein the composite material has an optical density of about 0.5 to about 0.9 and a path length of about 50 μm to about 200 μm. 56. The method of claim 55,
The composite material has an optical density of about 0.8 and a path length of about 100 μm. As a manufacturing method of a light emitting nanocrystal composite material,
(a) dispersing a plurality of said luminescent nanocrystals in said first polymeric material to form a mixture of luminescent nanocrystals and a first polymeric material;
(b) curing the mixture;
(c) producing particles from the cured mixture; And
(d) dispersing said particles in a second polymeric material to produce said composite material. 58. The method of claim 57,
And dispersing in (a) comprises dispersing the luminescent nanocrystals in aminosilicon. 58. The method of claim 57,
And dispersing in (a) comprises dispersing luminescent nanocrystals comprising CdSe or ZnS. 58. The method of claim 57,
The dispersing in (a) comprises dispersing luminescent nanocrystals comprising CdSe / ZnS, InP / ZnS, PbSe / PbS, CdSe / CdS, CdTe / CdS or CdTe / ZnS. Method of making a composite material. 58. The method of claim 57,
And adding a crosslinking agent to the mixture before the curing step in (b). 58. The method of claim 57,
Producing the particles comprises ball milling the cured mixture. 58. The method of claim 57,
Forming the composite material into a film, the method of manufacturing a light emitting nanocrystal composite material. As a light emitting diode (LED) device,
(a) an LED;
(b) a hermetically sealed container comprising a plurality of luminescent nanocrystals optically coupled to the LED; And
(c) a light guide optically coupled to the hermetically sealed container,
Light emitted from the LED is down converted by the nanocrystals and exits the surface of the light guide. 65. The method of claim 64,
The luminescent nanocrystals emit blue light, green light and red light, and the light is combined to produce white light. 65. The method of claim 64,
The LED emits ultraviolet light. 65. The method of claim 64,
The hermetically sealed container is a plastic container or a glass container. 68. The method of claim 67,
The hermetically sealed container is a glass capillary. 69. The method of claim 68,
Wherein the glass capillary has at least one dimension of about 100 μm to about 1 mm. 65. The method of claim 64,
Wherein the luminescent nanocrystals comprise CdSe or ZnS. 65. The method of claim 64,
The luminescent nanocrystals are core / shell nanocrystals comprising CdSe / ZnS, InP / ZnS, PbSe / PbS, CdSe / CdS, CdTe / CdS or CdTe / ZnS. 65. The method of claim 64,
Wherein the light guide is optically coupled to the hermetically sealed container via an adhesive or tape. 65. The method of claim 64,
The hermetically sealed container is spaced apart from the LED. 65. The method of claim 64,
Wherein the luminescent nanocrystals are dispersed in a polymeric matrix. As a light emitting diode (LED) device,
(a) an LED;
(b) a light guide optically coupled to the LED; And
(c) a plurality of luminescent nanocrystals dispersed in a region inside the light guide, the region comprising the plurality of luminescent nanocrystals extending along the length of the light guide,
The light emitted from the LED is down converted by the nanocrystals and exits the surface of the light guide. 78. The method of claim 75,
The luminescent nanocrystals emit blue light, green light and red light, and the light is combined to produce white light. 80. The method of claim 76,
The LED emits ultraviolet light. 78. The method of claim 75,
A first portion of light emitted from the LED is down converted by the light emitting nanocrystals, and a second portion of light emitted from the LED and the down converted light exit the surface of the light guide (LED) ) device. 79. The method of claim 78,
Wherein the LED emits blue light. 80. The method of claim 79,
Wherein the first portion of blue light emitted from the LED is down converted to green and red light by the light emitting nanocrystals. 79. The method of claim 80,
And a second portion of the blue light, the green light and the red light combine to produce white light. 78. The method of claim 75,
The nanocrystals comprise CdSe or ZnS. 78. The method of claim 75,
The nanocrystals are core / shell nanocrystals comprising CdSe / ZnS, InP / ZnS, PbSe / PbS, CdSe / CdS, CdTe / CdS or CdTe / ZnS. 78. The method of claim 75,
The light guide comprises one or more reflectors. 78. The method of claim 75,
Wherein said region is a layer of luminescent nanocrystals. 78. The method of claim 75,
And the region has a thickness that varies along the length of the light guide. 87. The method of claim 86,
And the thickness increases along the length of the light guide from the LED. 88. The method of claim 87,
Wherein the thickness increases approximately linearly along the length of the light guide. White light emitting diode (LED) device,
(a) a blue light emitting LED;
(b) a light guide optically coupled to the LED; And
(c) a plurality of CdSe / ZnS luminescent nanocrystals dispersed in a region inside the light guide, the region including the plurality of CdSe / ZnS luminescent nanocrystals extending along the length of the light guide,
The first portion of the blue light emitted from the LED is down converted to green light and red light by the CdSe / ZnS luminescent nanocrystals, and the second portion of the blue light, the green light and the red light are emitted and combined from the light guide. White light emitting diode (LED) devices. 90. The method of claim 89,
And the light guide comprises one or more reflectors. 90. The method of claim 89,
Wherein said region is a layer of CdSe / ZnS luminescent nanocrystals. 90. The method of claim 89,
And the region has a thickness that varies along the length of the light guide. 90. The method of claim 89,
And the thickness increases along the length of the light guide from the LED. 89. The method of claim 90,
And the thickness increases approximately linearly along the length of the light guide. White light emitting diode (LED) device,
(a) ultraviolet light emitting LED;
(b) a light guide optically coupled to the LED; And
(c) a plurality of CdSe / ZnS luminescent nanocrystals dispersed in a region inside the light guide, the region including the plurality of CdSe / ZnS luminescent nanocrystals extending along the length of the light guide,
Light emitted from the LED is down-converted to green light, red light and blue light by the CdSe / ZnS light emitting nanocrystals, and the green light and the red light and blue light are emitted from the light guide and combined to produce white light Diode (LED) device. 95. The method of claim 95,
And the light guide comprises one or more reflectors. 95. The method of claim 95,
Wherein said region is a layer of CdSe / ZnS luminescent nanocrystals. 95. The method of claim 95,
And the region has a thickness that varies along the length of the light guide. 99. The method of claim 98,
And the thickness increases along the length of the light guide from the LED. The method of claim 99, wherein
And the thickness increases approximately linearly along the length of the light guide. As a display system,
(a) a display;
(b) a plurality of light emitting diodes (LEDs);
(c) a light guide optically coupled to the LEDs, the light guide at least partially surrounded by the display; And
(d) a plurality of luminescent nanocrystals dispersed in a region inside the light guide, the region comprising the plurality of luminescent nanocrystals extending along the length of the light guide,
The light emitted from the LED is down converted by the nanocrystals and exits the surface of the light guide and displayed on the display. 102. The method of claim 101,
Wherein the luminescent nanocrystals emit blue light, green light and red light. 103. The method of claim 102,
And the LED emits ultraviolet light. 102. The method of claim 101,
And a first portion of the light emitted from the LED is down converted by the luminescent nanocrystals, and the second portion of the light emitted from the LED and the down converted light exit the surface of the light guide. 105. The method of claim 104,
And the LED emits blue light. 105. The method of claim 105,
And a first portion of blue light emitted from the LED is down converted to green light and red light by the light emitting nanocrystals. 107. The method of claim 106,
And the second portion of the blue light, the green light and the red light combine to produce white light. 102. The method of claim 101,
Wherein the luminescent nanocrystals comprise CdSe or ZnS. 102. The method of claim 101,
The luminescent nanocrystals are core / shell luminescent nanocrystals comprising CdSe / ZnS, InP / ZnS, PbSe / PbS, CdSe / CdS, CdTe / CdS or CdTe / ZnS. 102. The method of claim 101,
And the light guide comprises one or more reflectors. 102. The method of claim 101,
Wherein said region is a layer of luminescent nanocrystals. 102. The method of claim 101,
And the region has a thickness that varies along the length of the light guide. 112. The method of claim 112,
And the thickness of the region increases along the length of the light guide from the LED. 115. The method of claim 113,
And the thickness increases approximately linearly along the length of the light guide.

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