Light emitting device with a light-modifying material layer and manufacturing method utilizing an encapsulation template

Abstract

The solid state light emitting device includes at least one LED chip having a light-modifying material disposed over its entire top surface and lateral edges of the LED chip device of lumiphoric material, and at least one of a filler material layer in contact with the lateral surfaces of the LED chip, or a scattering material layer in contact with the lateral surfaces of the light-modifying material when the light-modifying material is a lumiphoric material. A method of manufacturing the solid state light emitting device includes applying the filler material to contact the lateral surfaces of the LED chip, adhering an encapsulation material template over the filler material, and applying the light-modifying material to the top surface of the LED chip through a window in the template, followed by removal of the template, optionally preceded by application of UV radiation to reduce adhesive tack and facilitate template removal.

Description

Detailed Description of the Invention

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims priority to U.S. patent application Ser. No. 17 / 885,765, filed Aug. 11, 2022, the entire contents of which are incorporated herein by reference.

[0002] [Technical field] SUMMARY OF THE INVENTION The subject matter herein relates to solid state light emitting devices that incorporate light-modifying materials disposed over one or more light emitting diodes, and methods for making such devices.

[0003] [background] Solid-state lighting devices, such as light-emitting diodes (LEDs), are increasingly being used in both consumer and commercial applications. LEDs have been widely adopted not only for backlighting liquid crystal displays and for providing continuously illuminated LED displays, but also in a variety of lighting environments. Lighting applications include vehicle headlamps, street lights, stadium lighting, luminaires, flashlights, and a variety of indoor, outdoor, and specialty lighting environments. Desired characteristics of LED devices for various end uses include high luminous efficacy, a uniform color point across the lighting area, long life, a wide color gamut, and compact size.

[0004] LEDs are solid-state devices that convert electrical energy into light and generally comprise one or more active layers (or active regions) of semiconductor material disposed between oppositely doped n-type and p-type layers. When a bias is applied to the doped layers, holes and electrons are injected into the one or more active layers, where they recombine and generate radiation, such as visible or ultraviolet radiation. LED chips typically comprise an active region that may be fabricated from, for example, silicon carbide, gallium nitride, gallium phosphide, indium phosphide, aluminum nitride, gallium arsenide-based materials, and / or organic semiconductor materials. Photons generated by the active region are omnidirectional.

[0005] Lumiphoric materials, such as phosphors, may be placed in the light emission path of the LED emitter to convert a portion of the light to a different wavelength. LED packages have been developed that can provide mechanical support, electrical connections, and encapsulation for the LED emitter. Light emission from the surface of the LED emitter typically interacts with the lumiphoric material and various elements or surfaces of the LED package before being emitted into the environment, thereby increasing the opportunity for light loss (e.g., due to internal absorption) and potential non-uniformity of the light emission. Thus, generating high-quality light with desired emission characteristics while providing high luminous efficiency can be challenging.

[0006] The present technology seeks improved solid state lighting devices with desirable lighting characteristics that can overcome the challenges associated with conventional lighting devices, and methods for manufacturing such devices. [overview] The present disclosure relates to a solid state light emitting device in various embodiments, comprising at least one LED mounted on a submount having a first surface; and a light-modifying material (e.g., a lumiphoric, reflective, absorbing, or thixotropic-type material) layer applied over an entire outer surface of the at least one LED distal to the first surface, wherein the lateral ends of the at least one LED are free of the lumiphoric material (or light-modifying material layer), and at least one additional layer is selected from (i) a filler material layer in contact with a lateral surface of the at least one LED, and (ii) a scattering material layer in contact with a lateral boundary of the light-modifying material layer when the light-modifying material layer is comprised of a lumiphoric material. A further aspect of the present disclosure relates to a method for manufacturing at least one light emitting device, comprising: applying a filler material layer in contact with a lateral surface of at least one LED mounted on a submount; adhering an encapsulation template on or over the filler material; applying a light-modifying material (e.g., lumiphoric material and / or light-scattering material) through a window defined in the encapsulation template to form a light-modifying material layer on the at least one LED; and removing the encapsulation template from the filler material.

[0007] In one aspect, the present disclosure relates to a solid state light emitting device comprising: at least one LED mounted on a first surface of a submount, wherein an outer surface of the at least one LED is distal from the first surface; a lumiphoric material layer comprising a lumiphoric material, the lumiphoric material layer disposed over the entire outer surface of the at least one LED, the lumiphoric material layer being free of the lumiphoric material at lateral edges of the at least one LED; and a filler material layer comprising a filler material and contacting a lateral surface of the at least one LED, the filler material comprising white or light reflective particles dispersed in a binder.

[0008] In certain embodiments, the solid state light emitting device further comprises a scattering material layer in contact with the lateral boundaries of the lumiphoric material layer. In certain embodiments, the scattering material layer has a maximum height substantially equal to the maximum height of the lumiphoric material layer.

[0009] In certain embodiments, the solid state light emitting device further comprises a lens material disposed in contact with the lumiphoric material layer and at least a portion of the scattering material layer. In certain embodiments, the filler material is compositionally identical to the scattering material layer.

[0010] In certain embodiments, the lumiphoric material layer overlaps a portion of the filler material layer proximate the periphery of the outer surface of at least one LED, and the lumiphoric material layer overlaps less than the entire filler material layer.

[0011] In certain embodiments, a central portion of the lumipholic material layer is positioned over the entire outer surface of at least one LED, and a peripheral portion of the lumipholic material layer is positioned over a portion of the fill material in an area around the periphery of the outer surface of at least one LED, and the average thickness of the peripheral portion of the lumipholic material is less than the average thickness of the central portion of the lumipholic material.

[0012] In certain embodiments, the periphery of the lumiphoric material layer has a non-uniform thickness. In certain embodiments, the solid state light emitting device further comprises a scattering material layer that (i) overlaps at least a portion of the periphery of the lumiphoric material layer and (ii) laterally bounds the lumiphoric material layer.

[0013] In certain embodiments, the filler material comprises white or reflective particles in a binder. In certain embodiments, the solid state light emitting device further comprises a lens material in contact with the lumiphoric material layer and disposed overlying at least a portion of the fill material layer.

[0014] In certain embodiments, the solid state light emitting device further comprises an elevated reflector structure overlying at least a portion of the fill material layer, the elevated reflector structure defining a reflector cavity aligned with the at least one LED, and a lens material disposed in the reflector cavity and in contact with the lumiphoric material layer.

[0015] In certain embodiments, the lumiphoric material layer, the filler material layer, the elevated reflector structure, and the lens material are substantially matched in coefficient of thermal expansion (CTE) such that the difference in CTE between any two or more of the lumiphoric material layer, the filler material layer, the elevated reflector structure, and the lens material is in a range of less than 20%, less than 15%, less than 10%, less than 5%, or less than 2%. Providing such CTE matching between components improves durability when the lighting device is subjected to numerous operating cycles, particularly in view of the high operating temperatures of the LED chip.

[0016] In another aspect, the present disclosure relates to a solid state light emitting device comprising: at least one LED mounted on a first surface of a submount, wherein an outer surface of the at least one LED is distal from the first surface; a lumiphoric material layer comprising a lumiphoric material, the lumiphoric material layer being disposed over the entire outer surface of the at least one LED, the lumiphoric material layer being free of the lumiphoric material on a side edge surface of the at least one LED; and a scattering material layer in contact with a lateral boundary of the lumiphoric material layer.

[0017] In certain embodiments, the scattering material layer has a height substantially equal to the maximum height of the lumiphoric material layer. In certain embodiments, the solid state light emitting device further comprises a filler material layer in contact with a lateral edge of the at least one LED, the filler material layer comprising white or light-reflecting particles dispersed in a binder, and a scattering material layer disposed over at least a portion of the filler material layer.

[0018] In certain embodiments, a portion of the lumiphoric material layer overlaps a portion of the filler material layer proximate the periphery of the outer surface of at least one LED. In certain embodiments, the solid state light emitting device further comprises a lens material disposed in contact with the lumiphoric material layer and at least a portion of the scattering material layer.

[0019] In certain embodiments, a central portion of the lumipholic material layer is positioned over the entire outer surface of at least one LED, and a peripheral portion of the lumipholic material layer is positioned over a portion of the fill material in an area around the periphery of the outer surface of at least one LED, and the average thickness of the peripheral portion of the lumipholic material is less than the average thickness of the central portion of the lumipholic material.

[0020] In another aspect, the present disclosure relates to a method for manufacturing at least one light emitting device, the method including: mounting at least one LED on a first surface of a submount, wherein an outer surface of the at least one LED is distal from the first surface; applying a filler material over the first surface of the submount so as to contact a side end surface of the at least one LED; adhering an encapsulation template on or over the filler material, the encapsulation template having at least a window positioned to align with the at least one LED and expose the outer surface of the at least one LED; applying a light modifying material to the outer surface of the at least one LED through the at least one window to form a light modifying material layer thereon; and removing the encapsulation template from the filler material.

[0021] In certain embodiments, the light-altering material includes at least one of a lumiphoric material or a scattering material. In certain embodiments, the sealing template comprises an ultraviolet release adhesive layer and a carrier, and the method further includes exposing the sealing template to ultraviolet radiation to reduce the tack of the ultraviolet release adhesive layer prior to removing the sealing template from the fill material.

[0022] In certain embodiments, the filler material comprises white or reflective particles in a binder (for example, but not limited to, TiO 2 particles in a silicone binder). In certain embodiments, the fill material comprises a removable material, and the method further comprises removing the fill material after removing the encapsulation template from the fill material.

[0023] In certain embodiments, the filler material is applied over the first surface of the submount by at least one process selected from the group consisting of: (a) jet pumping, (b) stencil printing, (c) screen printing, (d) dispensing, and (e) spraying.

[0024] In certain embodiments, the area of the at least one window is greater than the area of the exterior surface of the at least one LED, and applying the light-modifying material to the exterior surface of the at least one LED through the at least one window causes a portion of the light-modifying material to contact the fill material in an area outside the periphery of the exterior surface of the at least one LED.

[0025] In certain embodiments, an encapsulation template is applied over the intermediate layer that is raised against the fill material, and the light-modifying material is applied by spraying through the at least one window onto the outer surface of the at least one LED.

[0026] In certain embodiments, the light-modifying material is applied to the outer surface of the at least one LED in a manner that results in a layer thickness of the light-modifying material that varies with position along the outer surface of the at least one LED.

[0027] In certain embodiments, the method further includes applying a layer of transparent material over the encapsulating template prior to and / or after applying the light-modifying material to the outer surface of the at least one LED through the at least one window.

[0028] In certain embodiments, the method further includes, after removal of the encapsulation template, applying a layer of light-scattering or light-absorbing material over the filler material so as to contact the lateral boundaries of the light-modifying material layer.

[0029] In other aspects, any of the above aspects and / or various individual aspects and features described herein may be combined to further advantage. Any of the various features and elements disclosed herein may be combined with one or more other disclosed features and elements, unless otherwise indicated herein.

[0030] Other aspects, features, and embodiments of the present disclosure will become more fully apparent from the ensuing disclosure and appended claims. [Brief explanation of the drawings]

[0031] [Figure 1] FIG. 1 is a simplified cross-sectional view of a first conventional solid state light emitting device including an LED chip supported by a submount, a lumiphoric material layer covering the top surface of the LED chip and the submount and also covering the sides of the LED chip, a reflective material disposed on a portion of the lumiphoric material layer, and an overlaid arrow indicating a selected light beam emitted from the center of the LED chip. [Figure 2] FIG. 1 is a simplified cross-sectional view of a second conventional solid state light emitting device including an LED chip supported by a submount, a lumiphoric material layer covering the top and sides of the LED chip, and a reflective material disposed on the submount and on the side portions of the lumiphoric material layer. [Figure 3A] FIG. 1 is a simplified cross-sectional view depicting a step of utilizing an encapsulation template in the fabrication of at least a portion of a solid state light emitting device (or subassembly) according to one embodiment, wherein the device portion comprises a light-modifying (e.g., lumiphoric) material layer disposed over an upper surface of an LED chip supported by a submount and over a portion of a first fill material layer in contact with a lateral edge of the LED chip, and a second fill material layer in contact with the lateral edge of the lumiphoric material layer. [Figure 3B] FIG. 1 is a simplified cross-sectional view depicting a step of utilizing an encapsulation template in the fabrication of at least a portion of a solid state light emitting device (or subassembly) according to one embodiment, wherein the device portion comprises a light-modifying (e.g., lumiphoric) material layer disposed over an upper surface of an LED chip supported by a submount and over a portion of a first fill material layer in contact with a lateral edge of the LED chip, and a second fill material layer in contact with the lateral edge of the lumiphoric material layer. [Figure 3C]FIG. 1 is a simplified cross-sectional view depicting a step of utilizing an encapsulation template in the fabrication of at least a portion of a solid state light emitting device (or subassembly) according to one embodiment, wherein the device portion comprises a light-modifying (e.g., lumiphoric) material layer disposed over an upper surface of an LED chip supported by a submount and over a portion of a first fill material layer in contact with a lateral edge of the LED chip, and a second fill material layer in contact with the lateral edge of the lumiphoric material layer. [Figure 3D] FIG. 1 is a simplified cross-sectional view depicting a step of utilizing an encapsulation template in the fabrication of at least a portion of a solid state light emitting device (or subassembly) according to one embodiment, wherein the device portion comprises a light-modifying (e.g., lumiphoric) material layer disposed over an upper surface of an LED chip supported by a submount and over a portion of a first fill material layer in contact with a lateral edge of the LED chip, and a second fill material layer in contact with the lateral edge of the lumiphoric material layer. [Figure 3E] FIG. 1 is a simplified cross-sectional view depicting a step of utilizing an encapsulation template in the fabrication of at least a portion of a solid state light emitting device (or subassembly) according to one embodiment, wherein the device portion comprises a light-modifying (e.g., lumiphoric) material layer disposed over an upper surface of an LED chip supported by a submount and over a portion of a first fill material layer in contact with a lateral edge of the LED chip, and a second fill material layer in contact with the lateral edge of the lumiphoric material layer. [Figure 3F] FIG. 1 is a simplified cross-sectional view depicting a step of utilizing an encapsulation template in the fabrication of at least a portion of a solid state light emitting device (or subassembly) according to one embodiment, wherein the device portion comprises a light-modifying (e.g., lumiphoric) material layer disposed over an upper surface of an LED chip supported by a submount and over a portion of a first fill material layer in contact with a lateral edge of the LED chip, and a second fill material layer in contact with the lateral edge of the lumiphoric material layer. [Figure 3G] 3F after the addition of an optional transparent material layer overlying the light-modifying material and filler material. FIG. [Figure 3H] 3F is a simplified cross-sectional view depicting further steps in fabricating a solid-state light emitting device incorporating the device portion of FIG. 3F, including forming a cavity-defining elevated reflector structure disposed over the second fill material layer, and forming a lens material having an outwardly curved shape in contact with the lumiphoric material layer and the walls of the elevated reflector structure. [Figure 3I] 3F is a simplified cross-sectional view depicting further steps in fabricating a solid-state light emitting device incorporating the device portion of FIG. 3F, including forming a cavity-defining elevated reflector structure disposed over the second fill material layer, and forming a lens material having an outwardly curved shape in contact with the lumiphoric material layer and the walls of the elevated reflector structure. [Figure 3J] 3F is a simplified cross-sectional view depicting further steps in fabricating a solid-state light emitting device incorporating the device portion of FIG. 3F, including forming a lens material having an outwardly curved shape in contact with the lumiphoric material layer and a portion of the second fill material layer. [Figure 4A] FIG. 1 is a simplified cross-sectional view depicting a step of utilizing an encapsulation template in the fabrication of at least a portion of a solid state light emitting device according to one embodiment, wherein the device portion comprises a lumiphoric material layer (or other light-modifying material layer) disposed over an upper surface of an LED chip supported by a submount and over a portion of a first filler material layer that contacts the lateral edges of the LED chip, a second filler material layer contacting the lateral edges of the lumiphoric material layer, a peripheral portion of the lumiphoric material being reduced in thickness relative to its central portion, and a portion of the second filler material layer overlapping the peripheral portion of the lumiphoric material layer. [Figure 4B]FIG. 1 is a simplified cross-sectional view depicting a step of utilizing an encapsulation template in the fabrication of at least a portion of a solid state light emitting device according to one embodiment, wherein the device portion comprises a lumiphoric material layer (or other light-modifying material layer) disposed over an upper surface of an LED chip supported by a submount and over a portion of a first filler material layer that contacts the lateral edges of the LED chip, a second filler material layer contacting the lateral edges of the lumiphoric material layer, a peripheral portion of the lumiphoric material being reduced in thickness relative to its central portion, and a portion of the second filler material layer overlapping the peripheral portion of the lumiphoric material layer. [Figure 4C] FIG. 1 is a simplified cross-sectional view depicting a step of utilizing an encapsulation template in the fabrication of at least a portion of a solid state light emitting device according to one embodiment, wherein the device portion comprises a lumiphoric material layer (or other light-modifying material layer) disposed over an upper surface of an LED chip supported by a submount and over a portion of a first filler material layer that contacts the lateral edges of the LED chip, a second filler material layer contacting the lateral edges of the lumiphoric material layer, a peripheral portion of the lumiphoric material being reduced in thickness relative to its central portion, and a portion of the second filler material layer overlapping the peripheral portion of the lumiphoric material layer. [Figure 4D] FIG. 1 is a simplified cross-sectional view depicting a step of utilizing an encapsulation template in the fabrication of at least a portion of a solid state light emitting device according to one embodiment, wherein the device portion comprises a lumiphoric material layer (or other light-modifying material layer) disposed over an upper surface of an LED chip supported by a submount and over a portion of a first filler material layer that contacts the lateral edges of the LED chip, a second filler material layer contacting the lateral edges of the lumiphoric material layer, a peripheral portion of the lumiphoric material being reduced in thickness relative to its central portion, and a portion of the second filler material layer overlapping the peripheral portion of the lumiphoric material layer. [Figure 4E]FIG. 1 is a simplified cross-sectional view depicting a step of utilizing an encapsulation template in the fabrication of at least a portion of a solid state light emitting device according to one embodiment, wherein the device portion comprises a lumiphoric material layer (or other light-modifying material layer) disposed over an upper surface of an LED chip supported by a submount and over a portion of a first filler material layer that contacts the lateral edges of the LED chip, a second filler material layer contacting the lateral edges of the lumiphoric material layer, a peripheral portion of the lumiphoric material being reduced in thickness relative to its central portion, and a portion of the second filler material layer overlapping the peripheral portion of the lumiphoric material layer. [Figure 4F] FIG. 1 is a simplified cross-sectional view depicting a step of utilizing an encapsulation template in the fabrication of at least a portion of a solid state light emitting device according to one embodiment, wherein the device portion comprises a lumiphoric material layer (or other light-modifying material layer) disposed over an upper surface of an LED chip supported by a submount and over a portion of a first filler material layer that contacts the lateral edges of the LED chip, a second filler material layer contacting the lateral edges of the lumiphoric material layer, a peripheral portion of the lumiphoric material being reduced in thickness relative to its central portion, and a portion of the second filler material layer overlapping the peripheral portion of the lumiphoric material layer. [Figure 4G] 4F after the formation of a cavity-defining elevated reflector structure disposed over the second fill material layer, and the formation of a lens material having an outwardly curved shape in contact with the lumiphoric material layer and the walls of the elevated reflector structure. [Figure 4H] 4F after formation of a lens material having an outwardly curved shape in contact with the lumiphoric material layer and a portion of the second fill material layer. [Figure 5] 1 is a simplified cross-sectional view of at least a portion of a solid state light emitting device according to one embodiment, comprising a lumiphoric material layer disposed over a top surface of an LED chip and over a portion of a first fill material layer that contacts a lateral edge of the LED chip. [Figure 6]FIG. 1 is a simplified cross-sectional view of a solid state light emitting device comprising a cavity-defining elevated reflector structure disposed over a first fill material layer, and a lens material having a substantially hemispherical shape in contact with the walls of the elevated reflector structure and in contact with a lumiphoric material layer disposed over an LED chip. [Figure 7] 3F illustrates an enlarged cross-sectional view of the solid state light emitting device portion of FIG. 3F, in which a lumiphoric material layer is disposed over the top surface of the LED chip and over a portion of the first fill material layer in contact with the lateral edges of the LED chip, and the solid state light emitting device portion includes a second fill material in contact with the lateral edges of the lumiphoric material layer. [Figure 8] 8 is a simplified cross-sectional view of a solid state light emitting device according to one embodiment incorporating the device portion of FIG. 7, including a cavity-defining elevated reflector structure disposed over the second fill material layer, and a lens material having a substantially hemispherical shape in contact with the walls of the elevated reflector structure and in contact with the lumiphoric material layer. [Figure 9A] FIG. 1 is a simplified cross-sectional view of a solid state light emitting device comprising an LED chip supported by a submount and positioned in a cavity defined by an elevated reflector structure, showing application of a lumiphoric material having a non-uniform thickness on the LED chip and through a window defined in an encapsulation template positioned over the elevated reflector structure. [Figure 9B] 9B is a cross-sectional view of the solid state light emitting device of FIG. 9A after removal of the encapsulation template. DETAILED DESCRIPTION OF THE INVENTION

[0032] [Detailed explanation] The embodiments described below present the necessary information to enable one skilled in the art to practice the embodiments and illustrate the best modes of practicing the embodiments. Upon reading the following description in light of the accompanying drawings, one skilled in the art will understand the concepts of the present disclosure and will recognize applications of these concepts not specifically addressed herein. These concepts and applications are to be understood as being within the scope of this disclosure and the appended claims.

[0033] As used herein, terms such as first, second, etc. may be used to describe various elements, but it will be understood that these elements should not be limited by these terms. These terms are merely used to distinguish one element from another. For example, a first element could be referred to as a second element, and similarly, a second element could be referred to as the first element, without departing from the scope of the present disclosure. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0034] For example, when an element, such as a layer, region, or substrate, is referred to as being "on" or extending "onto" another element, it will be understood that the element may be directly on or extending directly onto the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly on" or extending "directly onto" another element, there are no intervening elements. Similarly, when an element, such as a layer, region, or substrate, is referred to as being "over" or extending "over" another element, it will be understood that the element may directly cover or extend directly over the other element, or there may be intervening elements. In contrast, when an element is referred to as being "directly over" or extending "directly over" another element, there are no intervening elements. When an element is referred to as being "connected" or "coupled" to another element, the element may be directly connected or coupled to the other element, or there may be intervening elements. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

[0035] For example, relative terms such as "below" or "above," or "upper" or "lower," or "horizontal" or "vertical" may be used herein to describe the relationship of one element, layer, or region to another element, layer, or region, as shown in the figures. It will be understood that these terms, and those described above, are intended to encompass various orientations of the device in addition to the orientation depicted in the figures.

[0036] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It will be further understood that the terms "comprises," "comprising," "includes," and / or "including," when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0037] Unless otherwise specified, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted to have a meaning consistent with their meaning in the context of the present specification and the relevant art, and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0038] Embodiments are described herein with reference to schematic diagrams of embodiments of the present disclosure. Therefore, actual dimensions of layers and elements may vary, and variations from the shapes of the illustrations may occur, for example, as a result of manufacturing techniques and / or tolerances. For example, regions shown or described as square or rectangular may have curvilinear or curved shapes, and regions shown as straight lines may have some irregularities. Therefore, regions shown in the figures are schematic, and their shapes are not intended to represent the exact shape of a region of a device, and are not intended to limit the scope of the present disclosure. Furthermore, the size of structures or regions may be exaggerated relative to other structures or regions for illustrative purposes, and therefore are provided to show the general structure of the present subject matter, and may or may not be drawn to scale. Herein, common elements between figures may be designated with common element numbers and may not be described again later.

[0039] Before delving into the specific details of various aspects of the present disclosure, a brief overview of the various elements that may be included in an exemplary LED of the present disclosure is provided for context. LED chips typically include an active LED structure or region that may include a number of different semiconductor layers arranged in various ways. The fabrication and operation of LEDs and their active structures are generally well known in the art and will only be briefly described herein. The layers of the active LED structure can be fabricated using well-known processes, including suitable fabrication processes using metalorganic chemical vapor deposition. The layers of the active LED structure can include a number of different layers, generally including an active layer sandwiched between oppositely doped n-type and p-type epitaxial layers, all of which are formed sequentially on a growth substrate. It is understood that additional layers and elements may also be included in the active LED structure, including, but not limited to, buffer layers, nucleation layers, superlattice structures, undoped layers, cladding layers, contact layers, and current spreading and light extraction layers and elements. The active layer may include a single quantum well, multiple quantum wells, double heterostructure, or superlattice structure.

[0040] Active LED structures can be fabricated from different material systems, some of which are based on III-nitrides. III-nitrides refer to semiconductor compounds formed between nitrogen (N) and elements in Group III of the periodic table, typically aluminum (Al), gallium (Ga), and indium (In). Gallium nitride (GaN) is a common binary compound. III-nitrides also refer to ternary and quaternary compounds, such as aluminum gallium nitride (AlGaN), indium gallium nitride (InGaN), and aluminum indium gallium nitride (AlInGaN). For III-nitrides, silicon (Si) is a common n-type dopant, and magnesium (Mg) is a common p-type dopant. Thus, the active layer, n-type layer, and p-type layer may comprise one or more layers of GaN, AlGaN, InGaN, and AlInGaN, undoped or doped with Si or Mg, as in III-nitride-based material systems. Other material systems include silicon carbide (SiC), organic semiconductor materials, and other III-V systems such as gallium phosphide (GaP), gallium arsenide (GaAs), indium phosphide (InP), and related compounds.

[0041] Active LED structures may be grown on growth substrates that can include a number of materials, such as sapphire, SiC, aluminum nitride (AlN), GaN, GaAs, glass, or silicon. SiC has certain advantages, such as a more closely matched crystal lattice with III-nitrides than other substrates, resulting in high-quality III-nitride films. SiC also has very high thermal conductivity, so that the total output power of III-nitride devices on SiC is not limited by the heat dissipation capabilities of the substrate. Sapphire is another common substrate for III-nitrides, and it also has certain advantages, including lower cost, an established manufacturing process, and good light-transmissive optical properties.

[0042] Different embodiments of the active LED structure may emit light of different wavelengths, depending on the composition of the active layer and the n-type and p-type layers. In some embodiments, the active LED structure emits blue light with a peak wavelength range of approximately 430 nanometers (nm) to 480 nm. In other embodiments, the active LED structure emits green light with a peak wavelength range of 500 nm to 570 nm. In other embodiments, the active LED structure emits red light with a peak wavelength range of 600 nm to 650 nm. In certain embodiments, the active LED structure may be configured to emit light outside the visible spectrum, including one or more regions of the ultraviolet (UV) spectrum.

[0043] The LED chip may also be coated with one or more lumiphoric materials (also referred to herein as lumiphores), such as phosphors, so that at least some light from the LED chip is absorbed by the one or more lumiphores and converted to one or more different wavelength spectra according to the characteristic emissions from the one or more lumiphores. In this regard, at least one lumiphore that receives at least a portion of the light generated by the LED source may re-emit light having a different peak wavelength than the LED source. The LED source and one or more lumiphoric materials may be selected so that their combined output provides light having one or more desired characteristics, such as, for example, color, color point, intensity, spectral density, etc. In certain embodiments, the aggregate emissions of the LED chip, optionally combined with one or more lumiphoric materials, may be configured to provide cool white, neutral white, or warm white, such as within a color temperature range of 2500 Kelvin (K) to 10,000 K. In certain embodiments, lumiphoric materials having peak wavelengths of cyan, green, amber, yellow, orange, and / or red may be used. In certain embodiments, the combination of the LED chip and one or more lumiphores (e.g., phosphors) emits a nearly white combination of light. The one or more phosphors may be yellow (e.g., YAG:Ce), green (e.g., LuAg:Ce), and red (e.g., Ca i-x-y Sr x EU y In other embodiments, the LED chip and corresponding lumiphoric material may be configured to emit the converted light primarily from the lumiphoric material, such that the total emission contains little or no appreciable emission corresponding to the LED chip itself.

[0044] Lumiphoric materials as described herein may be or include one or more of phosphors, scintillators, lumiphoric inks, quantum dot materials, daylight tape, and the like. Lumiphoric materials may be provided by any suitable means, such as coating directly on one or more surfaces of the LED, diffusing within an encapsulant configured to cover one or more LEDs, and / or coating on one or more optical or support elements (e.g., by powder coating, inkjet printing, or the like). In certain embodiments, lumiphoric materials may be downconverting or upconverting, or a combination of both downconverting and upconverting materials may be provided. In certain embodiments, multiple different (e.g., compositionally distinct) lumiphoric materials arranged to produce different peak wavelengths may be arranged to receive radiation from one or more LED chips. One or more lumiphoric materials may be provided in various shapes on one or more portions of the LED chip. In certain embodiments, one or more lumiphoric materials may be disposed on or over one or more surfaces of the LED chip in a substantially uniform manner. In other embodiments, one or more lumiphoric materials may be disposed on or over one or more surfaces of the LED chip in a non-uniform manner with respect to one or more of material composition, concentration, and thickness. In certain embodiments, the loading percentage of one or more lumiphoric materials may be varied on or between one or more outer surfaces of the LED chip. In certain embodiments, one or more lumiphoric materials may be patterned on a portion of one or more surfaces of the LED chip to include one or more stripes, dots, curves, or polygonal shapes. In certain embodiments, multiple lumiphoric materials may be disposed on or over the LED chip in different discrete regions or layers.

[0045] As used herein, a layer or region of a light-emitting device may be considered "transparent" when at least 80% of the emitted radiation striking that layer or region emerges through the layer or region. Additionally, as used herein, a layer or region of an LED may be considered "reflective" or embody a "mirror" or "reflector" when at least 80% of the emitted radiation striking that layer or region is reflected. In some embodiments, the emitted radiation includes visible light, such as blue and / or green LEDs, with or without lumiphoric materials. In other embodiments, the emitted radiation may include non-visible light. For example, in the context of GaN-based blue and / or green LEDs, silver (Ag) may be considered a reflective material (e.g., at least 80% reflective). In the case of UV LEDs, appropriate materials may be selected to provide desired, in some embodiments high, reflectivity and / or desired, in some embodiments low, absorption. In certain embodiments, a "light-transmitting" material may be configured to transmit at least 50% of the emitted radiation of a desired wavelength.

[0046] An LED package, in which one or more LED chips are mounted on a support member such as a submount or leadframe, may include one or more elements, such as a lumiphoric material and electrical contacts, among others. Suitable materials for the submount include, but are not limited to, ceramic materials such as aluminum oxide or alumina, AlN, or organic insulators such as polyimide (Pl) and polyphthalamide (PPA). In other embodiments, the submount may comprise a printed circuit board (PCB), sapphire, Si, or any other suitable material. For PCB embodiments, various PCB types may be used, such as standard FR-4 PCBs, metal-core PCBs, or any other type of PCB. In still further embodiments, the support structure may be embodied in a leadframe structure. A light-modifying material may be disposed within the LED package to reflect or redirect light from one or more LED chips in a desired emission direction or pattern.

[0047] As used herein, the term "light-modifying material" can include many different materials, including light-reflecting materials that reflect, redirect, and scatter light, light-absorbing materials that absorb light, lumiphoric materials, and materials that act as thixotropic agents. As used herein, the term "light-reflecting" refers to materials or particles that reflect, refract, scatter, or redirect light. With respect to light-reflecting materials, the light-modifying material may include at least one of fused silica, fumed silica, titanium dioxide (TiO), or metal particles suspended in a binder, such as silicone or epoxy. In certain embodiments, the particles may have a refractive index configured to refract light radiation in a desired direction. In certain embodiments, light-reflecting particles may also be referred to as light-scattering particles. The weight ratio of light-reflecting or scattering particles to binder may range from about 0.15:1 to about 0.5:1, or from about 0.5:1 to about 1:1, or from about 1:1 to about 2:1, depending on the desired viscosity before curing. With respect to light-absorbing materials, the light-modifying material may include at least one of carbon, silicon, or metal particles suspended in a binder, such as silicone or epoxy. The light-reflecting and light-absorbing materials may include nanoparticles. In certain embodiments, the light-modifying material may be configured in a substantially white color to reflect and redirect light. In other embodiments, the light-modifying material may be configured in a substantially opaque color, such as black or gray, to absorb light and increase contrast. In certain embodiments, the light-modifying material includes both light-reflecting and light-absorbing materials suspended in a binder.

[0048] A solid state light emitting device disclosed herein according to various embodiments comprises at least one LED mounted on a submount having a first surface, and a light-modifying material (e.g., lumiphoric material) layer applied over an entire outer surface of the at least one LED distal to the first surface, wherein the lateral edges of the at least one LED are free of the lumiphoric material (or light-modifying material layer), and the at least one additional layer is selected from (i) a filler material layer in contact with a lateral surface of the at least one LED, and (ii) a scattering material layer in contact with a lateral boundary of the light-modifying material layer when the light-modifying material layer is comprised of a lumiphoric material. A method for manufacturing at least one light emitting device includes applying a filler material layer to contact a lateral surface of at least one LED mounted on a submount; adhering an encapsulation template on or over the filler material; applying a light-modifying material (e.g., lumiphoretic material and / or light-scattering material) through a window defined in the encapsulation template to form a light-modifying material layer on the at least one LED; and removing the encapsulation template from the filler material.

[0049] A solid state light emitting device disclosed herein according to various embodiments comprises at least one LED mounted on a submount having a first surface, and a light-modifying material (e.g., lumiphoric material) layer applied over an entire outer surface of the at least one LED distal to the first surface, wherein the lateral edges of the at least one LED are free of the lumiphoric material (or light-modifying material layer), and the at least one additional layer is selected from (i) a filler material layer in contact with a lateral surface of the at least one LED, and (ii) a scattering material layer in contact with a lateral boundary of the light-modifying material layer when the light-modifying material layer is comprised of a lumiphoric material. A method for manufacturing at least one light emitting device includes applying a filler material layer to contact a lateral surface of at least one LED mounted on a submount; adhering an encapsulation template on or over the filler material; applying a light-modifying material (e.g., lumiphoretic material and / or light-scattering material) through a window defined in the encapsulation template to form a light-modifying material layer on the at least one LED; and removing the encapsulation template from the filler material.

[0050] Conventional templates have been used or tested by applicants to attempt to restrict the deposition of light-modifying materials (e.g., lumiphoric materials such as phosphors) to selected regions of one or more light-emitting device precursors, but such templates have suffered from various drawbacks that limit their usefulness. Such templates include stencil templates, three-dimensional printing templates, and the like. Such templates have not provided satisfactory results because they allowed the light-modifying material to pass between the template and the underlying layer, or they tended to cause the light-modifying material to stick to the template walls, resulting in poor control of the areas where the light-modifying material would remain on the underlying layer. For example, conventional screen printing processes for phosphor deposition utilize screen templates that do not seal well on uneven substrates (e.g., substrates with multiple light-emitting diodes and electrostatic discharge diodes mounted thereon), require significant downward force, and result in the phosphor particles migrating below the screen template. As another example, spraying a phosphor composition through windows defined in an unsealed template tends to result in the phosphor particles migrating below the template. However, locally depositing phosphor material over an LED disposed on a substrate without the use of a template is also difficult because surface effects (e.g., surface tension, which tends to cause meniscus formation) tend to prevent the phosphor mixture from covering the entire emitting area of the LED (including its corners) and / or tend to form a dome-shaped phosphor deposit of uneven thickness (i.e., thicker in the center of the LED chip than near its edges).

[0051] In certain embodiments, the sealing template comprises a carrier layer (e.g., a film) and an adhesive layer, which may be provided in the form of an adhesive tape. In certain embodiments, the carrier layer may be configured to transmit ultraviolet (UV) spectrum radiation, and the adhesive layer may include a UV-release adhesive that exhibits a reduction or loss of tack upon exposure of the adhesive to UV spectrum radiation. One or more windows may be defined in the sealing template by any suitable method, such as laser cutting, blade cutting, stamping, pressing, or the like.

[0052] In certain embodiments, the window-defining template may be applied to an underlying layer (e.g., with windows in the template aligned with one or more LEDs supported by the underlying layer) by pressing with sufficient force to engage the adhesive layer with the underlying layer. A light-modifying material (e.g., in certain embodiments, lumiphoric material and / or scattering material) may then be applied through the window (e.g., by spraying, dispensing, jet pumping, or other deposition method). In certain embodiments, the sealing template may have a thickness substantially equal to the desired deposition thickness of the light-modifying material. Optionally, any excess thickness of the light-modifying material may be removed by dragging a scooping member (e.g., a silicone or rubber blade, such as a squeegee) across the outer surface of the sealing template.

[0053] After deposition of the light-modifying material, the template may be exposed to UV radiation so that the template's adhesive layer exhibits reduced tack. The template may then be removed from the underlying layer by peeling (e.g., from its edges) so that the light-modifying material already deposited through the template's windows remains on the target surface after the template is removed. The ability to reduce the tack of the adhesive layer after material deposition allows the encapsulation template to be cleanly removed from the underlying layer without leaving adhesive residue or causing unintended removal of light-modifying material that would otherwise be laterally adhered to the edges of the encapsulation template's windows. The methods disclosed herein enable clean and complete application of the light-modifying material only in the intended locations, without depositing the light-modifying material in unintended locations or leaving residue on the underlying surface. When the light-modifying material is comprised of a lumiphoric material, providing the lumiphoric material only in the intended areas may facilitate achieving a uniform color point across the entire emission range and improve brightness levels and / or uniformity. In certain embodiments, multiple layers of light-altering (e.g., lumiphoric) material may be applied sequentially to the same (overlapping) area or to different (non-overlapping) areas, including through a single window in the sealing template or through different windows defined in a multi-window sealing template.

[0054] To provide context for the embodiments described herein, a conventional solid state light emitting device will be described in conjunction with FIGS. 1 and 2 before the embodiments of the present disclosure are described in connection with the remaining drawings. 1 is a simplified cross-sectional view of a first conventional solid-state light emitting device 10 including an LED chip 16 supported by a submount 12, with a first lumiphoric material layer portion 20 in contact with a top or outer surface 18 of the LED chip 16, a second lumiphoric layer portion 20A in contact with a side edge 19 of the LED chip 16, and a third lumiphoric layer portion 20B extending away from the LED chip 16 in contact with a portion of the first (top) surface 14 of the submount 12. During fabrication of the device 10, lumiphoric material may be applied over the outer and side edges 18, 19 of the LED chip 16 and over the submount 12 before a reflective material 25 is applied. The submount 12 (which may embody a substrate) has a second (bottom) surface 13 opposite the first surface 14 in contact with the LED chip 16. The reflective material 25 is disposed adjacent to the side of the LED chip 16, in contact with the second lumiphoric layer portion 20A and the third lumiphoric layer portion 20B. While light is generally emitted omnidirectionally from the LED chip 16, three light beams (i.e., B ) are emitted from the center point of the LED chip at low, medium, and high emission angles α1, α2, and α3. α1 ,B α2 , and B α3 ) are shown in FIG. 1. Light beam B with low radiation angle α1 α1 The light beam B having a medium emission angle α2 can be wavelength-converted in the third lumiphoric layer portion 20B and trapped between the submount 14 and the third lumiphoric layer portion 20B without emitting from the light-emitting device 10. α2 The light beam B having a high emission angle α3 can be wavelength converted by the second lumiphoric layer portion 20A and reflected by the reflective material 25 back to the LED 16, or can be reflected by the reflective material 25 outward through the first lumiphoric layer portion 20. α3 may be wavelength converted in the first lumiphoric layer portion 20 before exiting the light emitting device 10 , the first lumiphoric layer portion 20 defining the light emitting surface of the device 10 .

[0055] 2 is a simplified cross-sectional view of a second conventional solid state light emitting device 11 including an LED chip 16 supported by a submount 12, with a first lumiphoric material layer portion 20 in contact with a top or outer surface 18 of the LED chip 16 and a second lumiphoric layer portion 20A in contact with a side end surface 19 of the LED chip 16. The submount 12 (which may embody a substrate) has a second (bottom) surface 13 opposite a first surface 14 of the submount 12 that contacts the LED chip 16. A reflective material 25 is disposed laterally adjacent the LED chip 16, in contact with the second lumiphoric layer portion 20A and a portion of the top surface. The absence of lumiphoric material between the submount 12 and the reflective material 25 eliminates photon trapping between the submount 12 and the reflective material 25 (thereby improving the luminous efficiency of the solid-state light emitting device 11 relative to the device 10 illustrated in FIG. 1 ); however, the presence of the second lumiphoric material portion 20A still results in suboptimal luminous efficiency.

[0056] 1 and 2, solid state light emitting devices according to various embodiments of the present disclosure include a lumiphoric material deposited over the top surface of an LED chip, with the sides of the LED chip contacting a reflective material and free of lumiphoric material. Methods disclosed herein that utilize an encapsulation template to apply light-modifying materials (such as lumiphoric and / or light-scattering materials) are well suited to fabricating such solid state light emitting devices.

[0057] 3A-3F are simplified cross-sectional views depicting steps of utilizing an encapsulation template in fabricating at least a portion of a solid state light emitting device according to one embodiment. 3A shows an LED chip 16 mounted on a first (top) surface 14 of a submount 12, with the LED chip 16 having a top or outer surface 18 (disposed distally from the first surface 14 of the submount 12) and side end surfaces 19. In certain embodiments, the LED chip 16 may have a flip-chip configuration, and mounting the LED chip 16 on the first surface 14 of the submount may include making electrical connections between anode and cathode contacts (not shown) of the LED chip 16 and contact pads (not shown) of the submount 12.

[0058] FIG. 3B shows the item of FIG. 3A after adding a layer of filler material 30 over the submount 12 so as to contact the side end surface 19 of the LED chip 16, leaving the top or outer surface 18 of the LED chip 16 exposed. In certain embodiments, the filler material 30 includes a reflective material, such as white (e.g., titanium dioxide or TiO) particles contained in a silicone binder. The filler material layer 30 may be applied by any suitable method, such as jet pumping, screen printing, dispensing, spraying, or the like, optionally followed by a skimming step (e.g., with a rubber blade or squeegee) to remove excess filler material thickness. In certain embodiments, the filler material layer 30 has a lower boundary 31 in contact with the submount 12 and an upper boundary 32 disposed at substantially the same height or level as the top surface 18 of the LED chip 16. In certain embodiments, one or more second components (e.g., electrostatic discharge diodes) (not shown) having a height less than that of the LED chip 16 may also be supported by the submount 12 and may be encapsulated within the fill material layer 30. As shown in FIG. 3B , in certain embodiments, the upper boundary 32 of the fill material 30 may be substantially flush with the exposed outer surface 18 of the LED chip 16 to create a continuous plane.

[0059] 3C shows the item of FIG. 3B after the addition of an encapsulation template 35, which includes a carrier layer 36 and an adhesive layer 37 covering the filler material layer 30. The encapsulation template 35 may be applied by pressing with a flat member and / or one or more rollers (not shown). The encapsulation template 35 defines a window 38 (e.g., a pre-cut window) larger than but generally aligned with the LED chip 16, which also overlaps the LED-adjacent portion 32A of the filler material layer 30. In certain embodiments, the carrier layer 36 includes a material that transmits radiation in the UV spectrum, and the adhesive layer 37 includes a UV-releasing adhesive material. The top or outer surface 18 of the LED chip 16 is exposed through the window 38 defined in the encapsulation template 35.

[0060] FIG. 3D shows the item of FIG. 3C after application (using a deposition apparatus 39) of a light-modifying material (e.g., lumiphoric material) layer 40 deposited on the top or outer surface 18 of the LED chip 16 through a window defined in the template 35. As shown, the light-modifying material layer 40 is positioned over the entire outer surface 18 of the LED chip and also overlaps the LED-adjacent top surface portion 32A of the filler material layer 30, such that the light-modifying material layer 40 is wider than the top or outer surface 18 of the LED chip 16. Providing the light-modifying material layer 40 wider than the top or outer surface 18 of the LED chip 16 ensures that no portion of the LED chip 16's emission (including from its upper corners) escapes without interacting with the light-modifying material layer 40. If the light-modifying material layer 40 is made of a lumiphoric material, this may enhance the uniformity of the resulting emission color point across the emission area of the solid-state light emitting device. In certain embodiments, the light-affecting material layer 40 comprises a lumiphoric material in a silicone binder. Any suitable method may be used to apply the light-modifying material layer 40, such as, for example, spraying, dispensing, jet pumping, and the like. In some cases, any excess thickness of the light-modifying material 40 may be removed by dragging a skimming member (not shown) across the carrier layer 36 of the encapsulation template 35. Following application of the light-modifying material 40, such material may be cured and hardened, such as, for example, by heat, electromagnetic radiation, and / or other means.

[0061] Although only a single light-modifying material layer 40 is shown, it will be appreciated that multiple light-modifying (e.g., lumiphoric) material layers may be applied sequentially to the same (overlapping) or different (non-overlapping) areas, including through a single window in the sealing template or through different windows defined in a multi-window sealing template.

[0062] After (or during) curing of the light-modifying material, UV radiation may be applied to the sealing template 35 to reduce the tack of the adhesive layer 37. The sealing template 35 may then be removed (e.g., by mechanical peeling) from the fill material 30. Reducing the tack of the adhesive layer 37 prior to removing the sealing template 35 advantageously reduces the likelihood of leaving adhesive residue on the underlying fill material 30 and also reduces the likelihood that the light-modifying material 40 will remain laterally adhered to the boundaries of the windows 38 defined in the sealing template 35, such that when the sealing template 35 is removed from the underlying fill material 30, no portion of the light-modifying material 40 is removed, leaving clean side edges 41 of the light-modifying material 40. 3E shows the item of FIG. 3D after removal of encapsulation template 35, with the light-modifying material overlying not only the LED-adjacent top surface portion 32A of filler material layer 30, but also the entire top or outer surface 18 of LED chip 16, while the remaining top surface portion 32B of filler material layer 30 is exposed. As shown, the side edge surface 19 of LED chip 16 is completely covered with filler material 30 and is free of lumiphoretic material; no lumiphoretic material is provided between filler material 30 and submount 12.

[0063] FIG. 3F shows the item of FIG. 3E after adding a second filler material 45 to contact the lateral edges 41 of the light-modifying material 40 (overlying the outer surface 18 of the LED chip 16 and the LED-adjacent top surface portion of the filler material layer 30) and to contact the remaining top surface portion 32B of the filler material layer 30 to produce a solid state light emitting device portion or subassembly 50. In certain embodiments, the second filler material layer 45 includes a scattering material (e.g., fumed silica particles in a silicone binder) or a reflective material (e.g., titanium dioxide in a silicone binder). In certain embodiments, the second material layer 45 has a height substantially identical to that of the light-modifying material layer 40. In certain embodiments, the second filler material layer 45 has substantially the same composition as the (first) filler material layer 30. In certain embodiments, the second filler material layer 45 and the filler material layer 30 each include a reflective material in a binder, and the filler material layers 30, 45 may have the same or different reflectance values. In certain embodiments, second filler material layer 45 comprises a scattering material in a binder (e.g., silicone), and filler material layer 30 comprises a reflective material in a binder (e.g., silicone). Second filler material layer 45 may, in certain embodiments, serve to scatter and / or reflect light that leaks through lateral boundaries 41 of light modifying material layer 40, such that a desired beam cutoff pattern and / or improved light-emitting efficiency may be achieved. Solid state light emitting subassembly 50 is suitable for forming a variety of solid state light emitting devices that may include lenses in contact with the light modifying layer (with or without any transparent layer therebetween), and such lenses may optionally be held in reflector cavities of various sizes and shapes.

[0064] 3F , in certain embodiments, submount 12 comprises a ceramic material, LED chip 16 comprises a semiconductor material (e.g., a III-nitride material on a sapphire or silicon carbide substrate), and the remaining layers of solid state light emitting subassembly 50 (including filler material layer 30, light modifying material layer 40, and second filler material layer 45) have substantially matched coefficient of thermal expansion (CTE) properties, where “substantially matched” CTE properties may embody a difference in CTE between the layers of less than 20%, less than 15%, less than 10%, less than 5%, or less than 2%. In certain embodiments, filler material layer 30, light modifying material layer 40, and second filler material layer 45 may comprise the same binder (e.g., silicone) to which particles of the same or different compositions are added at the same or different concentrations.

[0065] Optionally, in certain embodiments, a transparent (transmissive) layer may be provided over second filler material layer 45 and light modifying material layer 40. One illustration of such an embodiment is shown in FIG. 3G, which shows solid state light emitting subassembly 50 with the addition of transparent layer 48 over second filler material layer 45 and light modifying material layer 40. In certain embodiments, transparent layer 48 may include silicone.

[0066] 3H shows the solid state light emitting subassembly 50 of FIG. 3F after formation of an elevated reflector structure 52 overlying the scattering material layer 45. The elevated reflector structure 52 has sloped reflector walls 54 that bound a reflector cavity 53. In certain embodiments, the elevated reflector structure 52 comprises reflective particles (e.g., titanium dioxide) in a silicone binder. In certain embodiments, a portion of the elevated reflector structure 52 may overlap the periphery of the light modifying material layer 40, preferably without overlapping the LED chip 16.

[0067] FIG. 3I illustrates a solid-state light emitting device 51 comprising the items of FIG. 3H (i.e., solid-state light emitting subassembly 50 and elevated reflector structure 52) after adding lens material 55 to reflector cavity 53 in contact with angled reflector wall 54. As shown, lens material 55 is disposed in contact with light modifying material 40 and reflector wall 54, and lens material 55 has an outwardly curved (convex) outer surface 56 through which light is extracted from device 51. In certain embodiments, lens material 55 comprises silicone. In certain embodiments, lens material 55 may be substantially CTE-matched to elevated reflector structure 52 and, in some cases, substantially CTE-matched to the remaining device layers (i.e., filler material layer 30, light modifying material layer 40, and second filler material layer 45); in certain embodiments, each of the above items may comprise silicone (with or without particulate matter added).

[0068] 3J shows a solid state light emitting device 61 comprising the solid state light subassembly 50 of FIG. 3F after the formation of a lens material 65 over light modifying material layer 40 and second filler material layer 45. A central portion of lens material 65 has an outwardly curved (convex, partially hemispherical) shape that merges with a planar extension 64 that extends over the periphery of second filler material layer 45. In certain embodiments, lens material 65 may be formed by molding over the solid state light emitting assembly 50 and may comprise silicone (or another material that is substantially CTE-matched to filler material layer 30, light modifying material layer 40, and second filler material layer 30).

[0069] The inventors have realized that, when using the encapsulation templates described herein, in certain instances, a light-modifying material (e.g., a lumiphoric material) applied over the top surface of the LED chip through a window defined in the encapsulation template can result in the light-modifying material having a peripheral portion with a smaller average thickness relative to the average thickness of the center of the light-modifying material. Such an effect may be adjusted during manufacturing by selecting and / or adjusting one or more of the following parameters: deposition method of the light-modifying material, directionality of deposition of the light-modifying material, viscosity of the light-modifying material, amount of deposited light-modifying material, thickness of the adhesive layer of the encapsulation template, tack of the adhesive layer of the encapsulation template, undercut of the adhesive layer of the encapsulation template, surface energy of the carrier layer of the encapsulation template, and / or surface energy of the filler material layer. In certain embodiments, a central portion of the light-modifying material layer is disposed over the entire outer surface of the LED chip, the side edges of the LED chip are covered with filler material (and are free of the light-modifying material layer), and a peripheral portion of the light-modifying material layer is disposed over the filler material layer, with the average thickness of the peripheral portion of the light-modifying material layer being less than the average thickness of the central portion of the light-modifying material layer. In certain embodiments, the peripheral portion of the light-modifying material layer has a non-uniform thickness, such as a thickness that decreases with increasing lateral distance from the LED chip. In certain embodiments, reflective and / or scattering material may be disposed in contact with the lateral boundaries of the light-modifying material, and a portion of the reflective and / or scattering material may overlap the thinner (peripheral) portion of the light-modifying material. In certain embodiments, the reflective and / or scattering material layer may have a maximum height substantially equal to the maximum height of the light-modifying material. In certain embodiments, the light-modifying material is comprised of a lumiphoric material.

[0070] 4A-4F are simplified cross-sectional views depicting steps of utilizing an encapsulating template in fabricating at least a portion of a solid state light emitting device according to one embodiment similar to the steps described in connection with FIGS. 3A-3F, however, where the solid state light emitting device portion or subassembly comprises a lumiphoric material layer (or other light-modifying material layer) having a reduced thickness at its periphery, and a portion of the second filler material layer contacts and overlaps the periphery of the lumiphoric material layer.

[0071] 4A shows an LED chip 16 mounted on a first (top) surface 14 of a submount 12, with the LED chip 16 having a top or outer surface 18 (disposed distally from the first surface 14 of the submount 12) and side end surfaces 19. In certain embodiments, the LED chip 16 may have a flip-chip configuration.

[0072] FIG. 4B shows the item of FIG. 4A after the addition of a (first) layer of filler material 30 covering the submount 12 so as to contact the side end surface 19 of the LED chip 16, leaving the top or outer surface 18 of the LED chip 16 exposed. The side end surface 19 of the LED chip 16 is free of lumiphoric material. In certain embodiments, the filler material 30 includes a reflective material, such as white (e.g., titanium dioxide or TiO) particles contained in a silicone binder. In certain embodiments, the filler material layer 30 has a lower boundary 31 in contact with the submount 12 and an upper boundary 32 disposed at substantially the same height or level as the top surface 18 of the LED chip 16, such that the upper boundary 32 of the filler material 30 may be substantially flush with the exposed outer surface 18 of the LED chip 16 to create a continuous plane.

[0073] 4C shows the item of FIG. 4B after the addition of an encapsulation template 35, which includes a carrier layer 36 and an adhesive layer 37 covering the filler material layer 30. The encapsulation template 35 defines a window 38 (e.g., a pre-cut window) that is larger than but generally aligned with the LED chip 16, and the window 38 also overlaps the LED-adjacent portion 32A of the filler material layer 30. In certain embodiments, the carrier layer 36 includes a material that transmits radiation in the UV spectrum, and the adhesive layer 37 includes a UV-releasing adhesive material. The top or outer surface 18 of the LED chip 16 is exposed through the window 38 defined in the encapsulation template 35.

[0074] FIG. 4D shows the item of FIG. 4C after application (using a deposition apparatus 39) of a lumiphoric material layer 40′ (or other light-modifying material layer) deposited on the top or outer surface 18 of the LED chip 16 through a window 38 defined in the template 35. As shown, the lumiphoric material layer 40′ is disposed over the entire outer surface 18 of the LED chip and also overlaps the LED-adjacent top surface portion 32A of the fill material layer 30, such that the lumiphoric material layer 40′ is wider than the top or outer surface 18 of the LED chip 16. Following application of the lumiphoric material layer 40′, such material may be cured or solidified, such as with heat, electromagnetic radiation, and / or other means. After (or during) curing of the light-modifying material, UV radiation may be applied to the encapsulation template 35 to reduce the tack of the adhesive layer 37. The encapsulation template 35 may then be removed (e.g., by mechanical peeling) from the fill material 30.

[0075] 4E illustrates the item of FIG. 4D after removal of encapsulation template 35, with central portion 40A' of lumiphoric material layer 40' overlying the entire top or outer surface 18 of LED chip 16 and peripheral portion 40B' of lumiphoric material layer 40' overlying LED-adjacent top surface portion 32A of filler material layer 30, while the remaining top surface portion 32B of filler material layer 30 is exposed. As shown, central portion 40A' of lumiphoric material layer 40' has a substantially constant thickness, while peripheral portion 40B' of lumiphoric material layer 40' has a thickness that decreases with increasing distance laterally from LED chip 16. In this regard, peripheral portion 40B' of lumiphoric material layer 40', with its curved lateral edges or boundaries 41', has an average thickness that is less than the average (and maximum) thickness of central portion 40A' of lumiphoric material layer 40'.

[0076] FIG. 4F shows the items of FIG. 4E after adding a second fill material layer 45′ in contact with the lateral edges or boundaries 41′ of the lumiphoric material 40′ and in contact with the remaining top surface portion 32B of the first fill material layer 30 to produce a solid state light emitting device portion or subassembly 50′. In certain embodiments, the second fill material layer 45′ includes a scattering material (e.g., fumed silica particles in a silicone binder) or a reflective material (e.g., titanium dioxide in a silicone binder). In certain embodiments, the second material layer 45′ has a maximum height substantially the same as the maximum height of the lumiphoric material layer 40′. Near the lateral edges or boundaries 41′ of the lumiphoric material 40′, the second fill material layer 45′ has a variable thickness that increases with increasing lateral distance from the LED chip 16, ultimately resulting in a constant thickness substantially equal to the maximum thickness of the lumiphoric material layer 40′. In certain embodiments, the second fill material layer 45′ has substantially the same composition as the first fill material layer 30. In certain embodiments, the second fill material layer 45′ and the first fill material layer 30 each include a reflective material in a binder, and the first and second fill material layers 30, 45′ may have the same or different reflectance values. In certain embodiments, the second fill material layer 45′ includes a scattering material in a binder (e.g., silicone), and the first fill material layer 30 includes a reflective material in a binder (e.g., silicone). The second fill material layer 45′ may, in certain embodiments, serve to scatter and / or reflect light that leaks through the lateral boundaries 41′ of the lumiphoric material layer 40′, such that a desired beam cutoff pattern and / or improved luminous efficiency may be achieved. The solid state light emitting subassembly 50' is suitable for forming a variety of solid state light emitting devices that may include a lens in contact with the lumiphoric material layer 40' (with or without a transparent layer therebetween), and such a lens may optionally be held in a reflector cavity of various sizes and shapes.

[0077] FIG. 4G shows a solid-state light emitting device 51′ comprising a solid-state light emitting subassembly 50′ with an elevated reflector structure 52 and a lens material 55 thereon. The elevated reflector structure 52 has angled reflector walls 54 that bound a reflector cavity 53. In certain embodiments, the elevated reflector structure 52 comprises reflective particles (e.g., titanium dioxide) in a silicone binder. In certain embodiments, a portion of the elevated reflector structure 52 may overlap the periphery of the lumiphoric material layer 40′, preferably without overlapping the LED chip 16. The lens material 55 is disposed in contact with the lumiphoric material layer 40′ and the reflector walls 54, and the lens material 55 has an outwardly curved (convex) outer surface 56 through which light is extracted from the device 51′. In certain embodiments, the lens material 55 comprises silicone. In certain embodiments, the lens material 55 may be substantially CTE-matched to the elevated reflector structure 52 and, in some cases, substantially CTE-matched to the remaining device layers (i.e., the first filler material layer 30, the lumiphoretic material layer 40', and the second filler material layer 45'), and in certain embodiments, each of the above items may include silicone (with or without particulate matter added).

[0078] FIG. 4H shows a solid-state light emitting device 61′ comprising the solid-state light subassembly 50′ of FIG. 4F after the formation of a lens material 65 over lumiphoric material layer 40′ and second fill material layer 45′. A central portion of lens material 65 has an outwardly curved (convex, partially hemispherical) outer surface 66 that merges with a flat extension 64 that extends over the periphery of second fill material layer 45′. In certain embodiments, lens material 65 may be formed by molding over the solid-state light emitting assembly 50′ and may comprise silicone (or another material that is substantially CTE-matched to first fill material layer 30, lumiphoric material layer 40′, and second fill material layer 45′; the aforementioned items may also include silicone into which particulate matter is bound).

[0079] While the embodiments described herein above include filler material laterally bounding a layer of light-modifying (e.g., lumiphoric) material, the present disclosure is not limited thereto. In certain embodiments, a solid state light emitting device includes a light-modifying material that is not laterally bounded by filler material that contacts the lateral edges of the light-modifying material.

[0080] 5 illustrates a solid state light emitting device portion 46′ according to one embodiment, including a light-modifying (e.g., lumiphoric) material layer 40 disposed over top surface 18 of LED chip 16 and also over LED-adjacent top surface portion 32A of filler material layer 30 that contacts side edge 19 of LED chip 16. LED chip 16 and filler material layer 30 are supported by submount 12. As shown, lateral edges or boundaries 41 of light-modifying material layer 40, as well as remaining surface portion 32B of the filler material layer, are exposed without any filler material contacting thereon.

[0081] FIG. 6 shows a solid-state light emitting device 71 according to one embodiment, comprising a device portion similar to that shown in FIG. 5 , covered with a cavity-defining reflector structure 72 and an outwardly curved lens material 65. An LED chip 16′ is supported by a submount 12, and a filler material layer 30 is also supported by the submount 12 in contact with a side edge 19′ of the LED chip 16′. A lumiphoric (or other light-modifying) material layer 40 extends over the entire outer surface of the LED chip 16′, and a peripheral edge 40A of the lumiphoric material layer 40 also extends over an LED-adjacent top surface portion 32A′ of the filler material layer 30. A cavity-defining reflector structure 72 is disposed over the remaining surface portion 32B′ of the filler material layer 30, defining angled reflector walls 74 that bound a reflector cavity containing a portion of the lens material 65, and further defining a top surface 73. The central portion of the lens material 65 has an outwardly curved (convex, partially hemispherical) surface 66, and the lens material 65 further has a flat extension 64 that overlies the upper surface 73 of the reflector structure 72. In certain embodiments, the lens material 65 may be formed by molding over the reflector structure 72 and the lumiphoric material layer 40, and may include silicone (or another material that is substantially CTE-matched to the first fill material layer 30, the lumiphoric material layer 40, and the reflector structure 72; the aforementioned items may also include silicone into which particulate matter is bound).

[0082] 7 provides an expanded view of the solid state light emitting device portion 50 of FIG. 3F, in which a lumiphoric (or other light-modifying) material layer 40 covers the top surface 18 of the LED chip 16 and is disposed over an LED-adjacent top surface portion 32A of the first filler material layer 30 that contacts a side edge 19 of the LED chip 16. The LED chip 16 and filler material layer 30 are supported by a submount 12. A second filler material layer 45 covers the remaining portion 32B of the first filler material layer 30 and is disposed in contact with a side edge 41 of the lumiphoric material layer 40, with the lumiphoric material layer 40 and second filler material layer 45 providing a substantially flat top surface suitable for depositing additional items (e.g., a reflector and / or lens structure) thereon.

[0083] 8 illustrates a solid state light emitting device according to one embodiment incorporating the device portion of FIG. 7, including an elevated reflector structure 72′ disposed over second fill material layer 45, the reflector structure defining a cavity that is filled with lens material 65. A central portion of lens material 65 has an outwardly curved (convex, partially hemispherical) shape with a substantially hemispherical outer surface 66 that merges with a flat extension 64 that extends over a flat top surface 73′ of elevated reflector structure 72′ and contacts sloped wall 74′ of elevated reflector structure 72′. Lens material 65 is also disposed in contact with lumiphoric material layer 40. Lumiphoric material layer 40 is disposed over top surface 18 of LED chip 16 and over an LED-adjacent top surface portion 32A of first filler material layer 30 that contacts side edge 19 of LED chip 16, such that the chip and first filler material layer 30 are supported by submount 12. Second filler material layer 45 is disposed over remaining portion 32B of first filler material layer 30 and contacts side edge 41 of lumiphoric material layer 40. In certain embodiments, all items of the light emitting device shown in FIG. 8 , except for the LED chip and submount, may be substantially CTE-matched, for example, by fabricating such items from silicone, optionally containing one or more particulate materials therein.

[0084] In certain embodiments, the encapsulating template may be elevated relative to the LED chip (e.g., relative to an LED chip optionally positioned within a cavity) during application of the light-modifying material layer, and the height of the encapsulating template, as well as the size and shape of the window defined in the encapsulating template, may be used to affect the pattern and / or thickness profile of the light-modifying material deposited on the LED chip (e.g., to result in a non-uniform thickness).

[0085] 9A shows a solid state light emitting device supported by a submount 12 and including an LED chip 16 disposed in a cavity 153 defined by an elevated reflector structure 152, with a window-defining encapsulation template 135 (comprising a carrier layer 136 and an adhesive layer 137) positioned above the cavity 153. The first surface 14 of the submount 12 supports the LED chip 16 and a filler material layer 30, which contacts a lateral surface 19 of the LED chip 16. The elevated reflector structure 152 defines sloped cavity sidewalls 154 that bound a portion of the cavity 153 together with an LED-adjacent top surface portion 32A of the filler material layer 30. The elevated reflector structure extends over the remaining top surface portion 32B of the filler material layer 30. The encapsulation template 135 covers the top surface of the elevated reflector structure 152 and extends beyond the sloped cavity sidewalls to define a window (through which a light-affecting (e.g., lumiphoric) material 140 is dispensed by a deposition apparatus 139 to be deposited over the LED chip 16 and the LED-adjacent top surface portion 32A of the fill material layer 30). The light-affecting material 140 may have a non-uniform thickness profile over the LED chip 16. After deposition of the light-affecting material 140, such material may be cured, the encapsulation template 135 may be treated with UV radiation to cause a reduction in or removal of the tack of the adhesive layer 137, and the encapsulation template 135 may be removed from the elevated reflector structure 152.

[0086] Figure 9B shows the items of Figure 9A after removing the encapsulation template to produce a solid state light emitting device 150, in which the light modifying material 140 on the LED chip 16 has a thickened central portion 140A and a thinned peripheral portion 140B, and has lateral boundaries 141 that may or may not be disposed in contact with the sloped reflector sidewalls 154. The remaining items in Figure 9B are the same as those described above in connection with Figure 9A.

[0087] Embodiments disclosed herein may provide one or more of the following advantageous technical effects: enabling the fabrication of solid state light emitting devices with improved luminous efficiency and / or color point uniformity across the emission area; simplifying the fabrication of solid state light emitting devices; and enabling the fabrication of solid state light emitting devices with non-uniform layers of light-modifying material.

[0088] Those skilled in the art will recognize improvements and modifications to the preferred embodiments of the present disclosure, and all such improvements and modifications are considered to be within the scope of the concepts disclosed in this specification and the claims that follow.

Claims

1. At least one LED mounted on the first surface of a submount, wherein the outer surface of the at least one LED is distal to the first surface, A luminifolic material layer comprising a luminifolic material, wherein the luminifolic material layer is arranged to cover and contact the entire outer surface of at least one LED, the proximal surface of the luminifolic material layer is positioned between opposing parallel distal surfaces of the luminifolic material layer and the outer surface of the at least one LED, there is no luminifolic material on the side end faces of the at least one LED, the central portion of the luminifolic material layer is positioned to cover the entire outer surface of the at least one LED, the average thickness of the peripheral portion of the luminifolic material layer is smaller than the average thickness of the central portion of the luminifolic material layer, and the proximal surface of the luminifolic material layer has a width greater than that of the distal surface, A filler layer comprising a filler material, wherein the filler layer is in contact with the side end face of at least one LED, and the filler material comprises white or light-reflecting particles dispersed in a binder, A scattering material layer in contact with the lateral boundary of the luminifolic material layer, Equipped with, The luminifolic material layer is arranged to cover at least a portion of the filler material layer adjacent to the outer periphery of the outer surface of at least one LED, and the peripheral edge of the luminifolic material layer is arranged on a portion of the filler material in the region surrounding the peripheral edge of the outer surface of at least one LED. The scattering material layer is formed along the lateral boundary of the peripheral edge of the luminifolic material layer, and a portion of the scattering material layer overlaps with the peripheral edge of the luminifolic material layer. The scattering material layer does not overlap with the central portion of the luminifolic material layer. Solid-state light-emitting devices.

2. The solid-state light-emitting device according to claim 1, wherein the scattering material layer has a maximum height substantially equal to the maximum height of the luminifolic material layer.

3. The solid-state light-emitting device according to claim 1 or 2, further comprising a lens material disposed in contact with at least a portion of the luminifolic material layer and the scattering material layer.

4. The solid-state light-emitting device according to claim 3, wherein the lens material covers at least a portion of the filling material layer.

5. The solid-state light-emitting device according to claim 1, wherein the luminifolic material layer overlaps less than the entirety of the filler material layer.

6. The solid-state light-emitting device according to claim 1, wherein the peripheral portion of the luminifolic material layer has an uneven thickness.

7. An elevated reflector structure, which is arranged on top of at least a portion of the filling material layer, and defines a reflector cavity that is aligned with the at least one LED, A lens material is disposed in the reflector cavity and in contact with the luminifolic material layer, The solid-state light-emitting device according to claim 1 or 2, further comprising:

8. The solid-state light-emitting device according to claim 7, wherein the coefficient of thermal expansion (CTE) of the luminifolic material layer, the filler material layer, the elevated reflector structure, and the lens material are substantially matched such that the difference in CTE between any two or more of the luminifolic material layer, the filler material layer, the elevated reflector structure, and the lens material is less than 20%.

9. A method for manufacturing at least one light-emitting device, Mounting at least one LED on the first surface of a submount, wherein the outer surface of the at least one LED is distal to the first surface. The filling material is applied to cover the first surface of the submount so as to be in contact with the side end face of at least one LED, The sealing template is bonded to or covering the filling material, wherein the sealing template has at least one window that is aligned with the at least one LED and positioned to expose the outer surface of the at least one LED. The light-changing material is applied to the outer surface of at least one LED through at least one of the windows, so as to form a layer of the light-changing material thereon. Removing the sealing template from the filling material, Methods that include...

10. The method according to claim 9, wherein the light-modifying material comprises at least one of a luminifolic material or a scattering material.

11. The method according to claim 9, wherein the sealing template comprises an ultraviolet-release adhesive layer and a carrier, and the method further comprises exposing the sealing template to ultraviolet radiation to reduce the tack of the ultraviolet-release adhesive layer prior to removing the sealing template from the filler material.

12. The method according to claim 9, wherein the filling material includes a removable material, and the method further comprises removing the filling material after the sealing template has been removed from the filling material.

13. The method according to any one of claims 9 to 12, wherein the filling material is coated over the first surface of the submount by at least one process selected from the group consisting of (a) jet pumping, (b) stencil printing, (c) screen printing, (d) dispensing, and (e) spraying.

14. The area of ​​the at least one window is larger than the area of ​​the outer surface of the at least one LED. Applying the light-changing material to the outer surface of the at least one LED through the at least one window causes a portion of the light-changing material to come into contact with the filler material in an area outside the outer periphery of the outer surface of the at least one LED. The method according to any one of claims 9 to 12.

15. The sealing template is applied to cover the intermediate layer which is raised relative to the filler material. The light-changing material is applied by spraying to the outer surface of the at least one LED through the at least one window. The method according to any one of claims 9 to 12.

16. The light-changing material is applied to the outer surface of at least one LED such that the thickness of the light-changing material layer varies depending on its position along the outer surface of the at least one LED. The method according to claim 15.

17. The method according to any one of claims 9 to 12, further comprising, after removal of the sealing template, applying a light scattering or light absorbing material layer to cover the filler material so as to be in contact with the lateral boundary of the light-modifying material layer.

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