Light-emitting diode device having a support structure including a patterned photomodifying layer

Abstract

Disclosed are light emitting devices including solid-state light emitting devices, light emitting diode (LED) devices, and LED packages with support elements for improving near-field and far-field light emission. LED chips (12-1, 12-2) can be mounted on the support element (14) in a manner that guides light through the support element in a desired direction of light emission. The support element includes an optical structure that laterally diffuses and mixes light within the support element. The optical structure includes various light modifying layers, such as light diffusing layers (40-1, 40-2) or light reflecting layers, that are arranged to effectively increase internal reflection for lateral spreading of light. The patterned arrangement of the light modifying layers includes portions that mask direct light emission from the LED chip, thereby laterally redistributing the light emission and enhancing the light-emitting surface (14). E ) improves near field and / or far field uniformity across the extended portion. The support element as described may be well suited for thin LED devices where the device height is less than or equal to the device width.

Description

[Technical Field]

[0001]

[0001] The present disclosure relates to a solid-state light-emitting device, a light-emitting device including a light-emitting diode and a light-emitting diode package having a support element including one or more patterned light-altering layers. [Background technology]

[0002]

[0002] Solid-state lighting devices such as light-emitting diodes (LEDs) are increasingly being used in both consumer and commercial applications. Advances in LED technology have resulted in light sources that are highly efficient, mechanically robust, and long-life. Thus, modern LEDs enable a variety of new display applications, such as video screens, and are routinely utilized for general lighting applications, frequently replacing incandescent and fluorescent light sources.

[0003]

[0003] An LED is a solid-state device that converts electrical energy into light and typically contains 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 across the doped layers, holes and electrons are injected into the active layer(s), where they recombine to produce light, such as visible or ultraviolet light. An LED chip typically contains an active region that may be fabricated from, for example, silicon carbide, gallium nitride, gallium phosphide, aluminum nitride, gallium arsenide-based materials, and / or organic semiconductor materials. Photons generated by the active region are emitted in all directions.

[0004]

[0004] LED packages have been developed that provide mechanical support, electrical connections, thermal management, encapsulation, and reflective surfaces for LED emitters to direct light emission in a desired direction. Light emitted from the surface of an LED emitter may interact with various elements or surfaces of the corresponding LED package before exiting the LED emitter. As LED package structures continue to evolve to meet modern applications, the challenge of producing high-quality light with desired light emission characteristics remains, especially as the overall size of LED packages continues to shrink. The art continues to develop improved LEDs and solid-state lighting devices with desired illuminance characteristics that can overcome the challenges associated with conventional lighting devices. Summary of the Invention [Means for solving the problem]

[0005]

[0005] The present disclosure relates to a light emitting device including a solid-state light emitting device, a light emitting diode (LED) device, and an LED package with a support element for improving near-field and far-field emission. The LED chip can be mounted on the support element so that light is directed through the support element in a desired emission direction. The support element includes an optical structure that laterally spreads and mixes light within the support element. The optical structure includes various light-modifying layers, such as a light-diffusing layer or a light-reflective layer, arranged to effectively increase internal reflection for the lateral spread of light. The patterned arrangement of the light-modifying layers includes portions that mask direct emission for the LED chip, thereby laterally redistributing the emission and improving near-field and / or far-field uniformity across an extended portion of the light-emitting surface. The described support element may be well suited for thin LED devices, where the device height is equal to or less than the device width. Other patterned structures are also described that are not typically considered support elements but may provide similar improvements in near-field and / or far-field emission.

[0006] In one aspect, an LED device includes one or more LED chips, a light-transmitting layer on the one or more LED chips, and a light-modifying layer arranged in a pattern on the light-transmitting layer, the light-transmitting layer being between the light-modifying layer and the one or more LED chips. In certain embodiments, the light-modifying layer includes one or more of a light-diffusing layer, a light-scattering layer, and a light-reflecting layer. In certain embodiments, the light-modifying layer includes a light-diffusing layer, the light-diffusing layer including light-diffusing particles dispersed within a light-transmitting material or a textured surface. In certain embodiments, the light-modifying layer includes a light-reflecting layer, the light-reflecting layer having a thickness of 100 nanometers (nm) or less. The LED package may further include a light-absorbing layer on the light-modifying layer and on portions of the light-transmitting layer between portions of the light-modifying layer. In certain embodiments, the pattern includes discontinuous segments of the light-modifying layer. In other embodiments, the pattern includes connected segments of the light-modifying layer. The pattern may comprise segments of the light modifying layer aligned with one or more LED chips.

[0007]

[0007] In a particular embodiment, the one or more LED chips include a first LED chip configured to provide a first peak wavelength in the range of 430 nanometers (nm) to 480 nm, a second LED chip configured to provide a second peak wavelength in the range of 500 nm to 570 nm, and a third LED chip configured to provide a third peak wavelength in the range of 600 nm to 750 nm.

[0008] The LED package may further include a base structure on which one or more LED chips are mounted, the base structure including an insulating submount having electrically conductive traces or a lead frame structure. In certain embodiments, the light-modifying layer includes at least one anodized metal layer. The LED package may further include a current spreading layer between the at least one anodized metal layer and the one or more LED chips. In certain embodiments, the at least one anodized metal layer includes a light-absorbing pigment. In certain embodiments, the at least one anodized metal layer includes localized regions having different thicknesses. In certain embodiments, the pattern is a molded pattern or an embossed pattern. In certain embodiments, the pattern includes individual features having sizes ranging from 10 nm to 900 nm.

[0009] In another aspect, an LED device includes one or more LED chips, a first light modifying layer on the one or more LED chips, a second light modifying layer on the first light modifying layer, the first light modifying layer being closer to the one or more LED chips than the second light modifying layer, and a light transmitting layer between the first and second light modifying layers, at least one of the first and second light modifying layers being disposed in a pattern on the light transmitting layer. In certain embodiments, the first and second light modifying layers each include a light diffusing layer or a light reflecting layer.

[0010] In certain embodiments, the pattern comprises one or more segments of the second light-modifying layer. The first light-modifying layer can be arranged in an additional pattern comprising one or more segments of the first light-modifying layer. In certain embodiments, the one or more segments of the first light-modifying layer are laterally spaced from one or more LED chips to form openings in the first light-modifying layer aligned with the one or more LED chips. In certain embodiments, the one or more segments of the first light-modifying layer are positioned between one or more LED chips and a light-transmissive layer, and the one or more segments of the first light-modifying layer are aligned with the one or more LED chips. In certain embodiments, the one or more segments of the first light-modifying layer are arranged in an inverse pattern with the one or more segments of the second light-modifying layer. In certain embodiments, the one or more segments of the first light-modifying layer are arranged in the same pattern as the one or more segments of the second light-modifying layer. In certain embodiments, the one or more segments of the second light-modifying layer form a checkerboard pattern. In certain embodiments, the one or more segments of the second light modifying layer comprise alternating segments that vary in surface area or shape. In certain embodiments, the one or more segments of the second light modifying layer comprise a first segment disposed over one or more LED chips and multiple second segments disposed around the first segment. In certain embodiments, the one or more segments of the second light modifying layer comprise multiple segments that vary in density across the LED device. In certain embodiments, at least one of the first light modifying layer and the second light modifying layer comprises an anodized metal layer.

[0011] In other aspects, any of the foregoing aspects may be combined individually or together, and / or with various separate aspects and features as described herein to provide additional advantages. Any of the various features and elements disclosed herein may be combined with one or more of the other disclosed features and elements, unless indicated to the contrary herein.

[0012] Those skilled in the art will appreciate the scope of the present disclosure and realize additional aspects thereof after reading the following detailed description of the preferred embodiments in conjunction with the accompanying drawings.

[0013] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate several aspects of the disclosure and, together with the description, serve to explain the principles of the disclosure. [Brief explanation of the drawings]

[0013] [Figure 1]

[0014] 1 is a cross-sectional view of a light-emitting diode (LED) device including multiple LED chips mounted on a mounting surface of a support element. [Figure 2]

[0015] 2 is a cross-sectional view of an LED device similar to that of FIG. 1, except that the support element further includes a diffusing material therein. [Figure 3]

[0016] 2 is a cross-sectional view of an LED device similar to that of FIG. 1, except that the support element includes a light-transmitting layer and a light-diffusing layer. [Figure 4]

[0017] FIG. 4 is a cross-sectional view of an improved LED device relative to the LED device of FIG. 3, in which the support element includes a multi-layer structure that forms an interior mixing chamber for improving near-field and far-field emission while maintaining a low profile for the LED device. [Figure 5]

[0018] 5 is a cross-sectional view of an LED device similar to that of FIG. 4, for an embodiment in which the support element further includes a light-absorbing layer. [Figure 6]

[0019] 5 is a cross-sectional view of an LED device similar to that of FIG. 4, except that the support element includes first and second light-reflecting layers on opposite sides of the light-transmitting layer. [Figure 7]

[0020] 5 is a cross-sectional view of an LED device similar to that of FIG. 4, except that the support element includes a light-transmitting layer between a first light-modifying layer and a second light-modifying layer different from the first light-modifying layer. [Figure 8]

[0021] 8 is a cross-sectional view of an alternative configuration of the support element of FIG. 7 for an embodiment in which the first and second light modifying layers are filled with air voids or air bubbles to promote increased light scattering. [Figure 9]

[0022] 8 is a cross-sectional view of an alternative configuration of the support element of FIG. 7 for an embodiment in which the first and second light-modifying layers are filled with oxide particles having different shapes and / or particle size distributions or media with different refractive index values ​​to increase light scattering. [Figure 10]

[0023] 5 is an exploded view of a typical LED device similar to that of FIG. 4, in which at least one light-modifying layer is patterned to tailor the emission pattern from the LED device. [Figure 11A]

[0024] 11 is a cross-sectional view of an LED device similar to that of FIG. 10, but including first and second light-modifying layers on opposite sides of a light-transmitting layer. [Figure 11B]

[0025] 11B is an exemplary top view of the LED device of FIG. 11A. [Figure 12]

[0026] FIG. 11C is a cross-sectional view of an LED device similar to that of FIGS. 11A and 11B, in which the first light-modifying layer is also patterned. [Figure 13]

[0027] 13 is a cross-sectional view of an LED device similar to that of FIG. 12, in which the first light-modifying layer is patterned with segments aligned with the LED chip to block direct LED chip light emission. [Figure 14]

[0028] 13 is a cross-sectional view of an LED device similar to that of FIG. 12 for an embodiment in which the pattern of the first light modifying layer is the inverse of the pattern of the second light modifying layer. [Figure 15]

[0029] 15 is a cross-sectional view of an LED device similar to that of FIG. 14 for an embodiment in which the pattern of the first light modifying layer is the same as the pattern of the second light modifying layer. [Figure 16]

[0030] FIG. 10 is a top view of an LED device for an embodiment in which the second light modifying layer is disposed in a checkerboard pattern over the entire LED device. [Figure 17]

[0031] 17 is a top view of an LED device similar to that of FIG. 16 for an embodiment in which the segments of the second light-modifying layer vary in size along the LED device. [Figure 18]

[0032] 17 is a top view of an LED device similar to that of FIG. 16 for an embodiment in which segments of the second light-modifying layer are discontinuously formed throughout the LED device. [Figure 19]

[0033] 17A and 17B are top views of an LED device similar to that of FIG. 16 for an embodiment in which the shape and / or size of the segments of the second light-modifying layer vary throughout the LED device. [Figure 20]

[0034] 20 is a top view of an LED device similar to that of FIG. 19 for an embodiment in which the density of the segments of the second light-modifying layer varies across the LED device. [Figure 21]

[0035] A top view of an LED device similar to that of Figure 16 for an embodiment in which the pattern includes a single large segment of the second light-modifying layer aligned with the LED chip and covering a large portion of the top of the LED device. [Figure 22]

[0036] FIG. 22 is a top view of an LED device similar to that of FIG. 21 in which a single segment of the second light-modifying layer is provided in a transverse band between two opposing peripheral edges of the LED device. [Figure 23]

[0037] 23 is a top view of an LED device similar to that of FIG. 22 in which a single segment of the second light-modifying layer is provided with a surface area corresponding to the combined surface area or footprint of the LED chips. [Figure 24]

[0038] 23 is a top view of an LED device similar to that of FIG. 22, except that the second light-modifying layer forms a pattern with individual segments, each segment aligned or otherwise matched to the footprint of a corresponding individual one of the LED chips. [Figure 25]

[0039] FIG. 25A is an exploded cross-sectional view of a generic LED device similar to that of FIG. 10 for an embodiment in which the base structure is a lead frame structure.

[0014]

[0040] FIG. 25B is an assembled cross-sectional view of the LED device of FIG. 25A. [Figure 26]

[0041] FIG. 26A is a partially exploded cross-sectional view of a typical LED device similar to that of FIG. 10 for an embodiment in which the light-modifying layer includes an anodized metal structure, illustrating a manufacturing step prior to anodization.

[0042] FIG. 26B is a partially exploded cross-sectional view of the LED device of FIG. 26A after anodization. DETAILED DESCRIPTION OF THE INVENTION

[0015]

[0043] The embodiments described below represent the information necessary to enable one skilled in the art to realize the embodiments and illustrate the best modes for achieving them. Upon reading the following description in conjunction with 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 should be understood to be within the scope of this disclosure and the appended claims.

[0016]

[0044] 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 used only to distinguish one element from another. For example, a first element can be referred to as a second element, and similarly, a second element can be referred to as a 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.

[0017]

[0045] When an element such as a layer, region, or substrate is referred to as being "on" or extending "upon" another element, it will be understood that the element may be directly on or extending directly onto the other element, or that 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 "above" or extending "upon" another element, it will be understood that the element may be directly on or extending directly onto the other element, or that 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. It will also be understood that 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.

[0018]

[0046] Relative terms such as "lower" or "above" or "upper" or "bottom" 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 illustrated in the figures. It is understood that these terms, and those discussed above, are intended to encompass various orientations of the device in addition to the orientation depicted in the figures.

[0019]

[0047] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly dictates otherwise. It will be further understood that the terms "comprises," "comprising," "including," and / or "comprising," as 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.

[0020]

[0048] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Terms used herein should be interpreted as having a meaning consistent with the meaning in the context of this specification and related art, and will be further understood not to be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0021]

[0049] Embodiments are described herein with reference to schematic diagrams of embodiments of the present disclosure. As such, actual dimensions of layers and elements may vary, and variations from the shapes of the figures are expected, for example, as a result of manufacturing techniques and / or tolerances. For example, regions illustrated or described as square or rectangular may have rounded or curved features, and regions illustrated as straight lines may have some irregularities. Accordingly, regions illustrated in the figures are schematic, and their shapes are not intended to illustrate the exact shape of a region of a device or to limit the scope of the disclosure. Additionally, the size of structures or regions may be exaggerated relative to other structures or regions for illustrative purposes and, therefore, are provided to illustrate the general structure of the present subject matter and may or may not be drawn to scale. Boundaries between various adjacent layers may be sharp or more gradual, depending on the intended surface finish and details of the manufacturing process. Elements common between figures may be illustrated with common element numbers herein and may not be described again later.

[0022]

[0050] The present disclosure relates to a light-emitting device including a solid-state light-emitting device, a light-emitting diode (LED) device, and an LED package with a support element for improving near-field and far-field emission. The LED chip can be mounted on the support element so that light is directed through the support element in a desired emission direction. The support element includes an optical structure that laterally spreads and mixes light within the support element. The optical structure includes various light-modifying layers, such as light-diffusing or light-reflecting layers, arranged to effectively increase internal reflection for lateral spreading of the light. The patterned arrangement of the light-modifying layers includes portions that mask the direct emission of the LED chip, thereby laterally redistributing the emission and improving near-field and / or far-field uniformity across an extended portion of the light-emitting surface. The described support element may be well-suited for thin LED devices, where the device height is equal to or less than the device width. Other patterned structures that would not normally be considered support elements but that provide similar improvements in near-field and / or far-field emission are also described.

[0023]

[0051] Before delving into the specific details of various aspects of the present disclosure, an overview of the various elements that may be included in an exemplary LED device of the present disclosure is provided for context. An LED chip typically comprises an active LED structure or region that may have a number of different semiconductor layers arranged in various ways. The fabrication and operation of LEDs and their active structures are generally known in the art and will be discussed only briefly herein. The layers of the active LED structure can be fabricated using known processes, with a suitable process being fabrication using metal organic chemical vapor deposition. The layers of the active LED structure can comprise many different layers, and typically comprise an active layer sandwiched between n-type and p-type oppositely doped epitaxial layers, all of which are formed sequentially on a growth substrate. It is understood that the active LED structure may also include additional layers and elements, including, but not limited to, buffer layers, nucleation layers, super lattice structures, undoped layers, cladding layers, contact layers, current spreading layers, light extraction layers, and elements. The active layer may comprise a single quantum well, multiple quantum well, double heterostructure, or super lattice structure.

[0024]

[0052] The active LED structure can be fabricated from different material systems, some of which are group III nitride-based. Group III nitrides refer to semiconductor compounds formed from nitrogen (N) and elements from group III of the periodic table, usually aluminum (Al), gallium (Ga), and indium (In). Gallium nitride (GaN) is a common binary compound. Group 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 group III nitrides, silicon (Si) is a common n-type dopant, and magnesium (Mg) is a common p-type dopant. Thus, for III-nitride based material systems, the active, n-type, and p-type layers may include one or more layers of undoped or Si- or Mg-doped GaN, AlGaN, InGaN, and AlInGaN. 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.

[0025]

[0053] The active LED structure can be grown on a growth substrate, which can include many materials, such as sapphire, SiC, aluminum nitride (AlN), GaN, GaAs, glass, or silicon. SiC has certain advantages, such as a closer crystal lattice match with III-nitrides than other substrates, resulting in high-quality III-nitride films. SiC also has very high thermal conductivity, so the total output power of III-nitride devices on SiC is not limited by the heat dissipation of the substrate. Sapphire is another common substrate for III-nitrides and also has certain advantages, such as lower cost, an established manufacturing process, and good optical properties with good light transmission.

[0026]

[0054] Different embodiments of the active LED structure can emit light of different wavelengths, depending on the configuration of the active layer, n-type layer, and p-type layer. In certain embodiments, the active LED structure emits blue light with a peak wavelength range of approximately 430 nanometers (nm) to 480 nm, green light with a peak wavelength range of 500 nm to 570 nm, or red light with a peak wavelength range of 600 nm to 700 nm. In certain embodiments, the active LED structure can be configured to emit light outside the visible spectrum, including one or more portions of the ultraviolet (UV) spectrum. The UV spectrum is typically divided into three wavelength range categories, designated by the letters A, B, and C. Thus, UV-A light is typically defined as a peak wavelength range of 315 nm to 400 nm, UV-B is typically defined as a peak wavelength range of 280 nm to 315 nm, and UV-C is typically defined as a peak wavelength range of 100 nm to 280 nm. UV LEDs have attracted particular attention for use in applications related to disinfecting microorganisms in air, water, and surfaces, among others. In other applications, UV LEDs may be provided with one or more lumiphoric materials to provide the LED package with aggregated light emission having a broad spectrum and improved color quality for visible light applications. In certain embodiments, a single LED package may include multiple LED chips, one or more of which may be configured to provide a different peak wavelength than the other LED chips.

[0027]

[0055] The LED chip may also be coated with one or more luminescent materials (also referred to herein as luminescent materials), such as phosphors, such that at least a portion of the light from the LED chip is absorbed by the one or more luminescent materials and converted to one or more different wavelength spectra according to the characteristic emission from the one or more luminescent materials. In this regard, at least one luminescent material that receives at least a portion of the light generated by the LED light source may re-emit light having a different peak wavelength than the LED light source. The LED light source and one or more luminescent materials may be selected so that their combined output provides light with one or more desired characteristics, such as color, color point, intensity, spectral density, color rendering index, etc. In certain embodiments, the total emission of the LED chip, optionally in combination with one or more luminescent materials, may be arranged to provide cool white, neutral white, or warm white light, such as within a color temperature range of 2500 Kelvin (K) to 10,000 K. In certain embodiments, luminescent materials having peak wavelengths of cyan, green, amber, yellow, orange, and / or red may be used. In some embodiments, the combination of the LED chip and one or more light emitters (e.g., phosphors) emits a generally white light combination. 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 AlSiN3) light-emitting phosphors, and combinations thereof.

[0028]

[0056] The luminescent materials described herein may be or include one or more of a phosphor, a scintillator, a luminescent ink, a quantum dot material, day glow tape, etc. The luminescent material may be provided by any suitable means, such as directly coated on one or more surfaces of the LEDs, dispersed in an encapsulant configured to cover one or more LEDs, embedded in an optical or support element, and / or coated on one or more optical or support elements (e.g., by powder coating, inkjet printing, etc.). In certain embodiments, the luminescent material may be down-converting or up-converting, and a combination of both down-converting and up-converting materials may be provided. In certain embodiments, multiple different (e.g., different composition) luminescent materials arranged to produce different peak wavelengths may be arranged to receive the emitted light from one or more LED chips.

[0029]

[0057] As used herein, a layer or region of a light-emitting device may be considered “transparent” if at least 50% or at least 80% of the optical radiation impinging on that layer or region passes through that layer or region and emerges. Additionally, as used herein, a layer or region of an LED may be considered “reflective” or embody a “mirror” or “reflector” if more than 50% or at least 80% of the optical radiation impinging on that layer or region is reflected. In some embodiments, the optical radiation comprises visible light, such as blue and / or green LEDs, with or without luminescent materials. In other embodiments, the optical radiation may comprise 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). For UV LEDs, appropriate materials may be selected to provide a desired, in some embodiments, high reflectivity and / or a desired, in some embodiments, low absorption. In certain embodiments, a “light-transmitting” material may be configured to transmit at least 50% of the optical radiation of a desired wavelength. In other embodiments, a "light-transmitting" material may be configured to transmit lower values, e.g., at least 10% or at least 25% of light having a desired wavelength, while still being useful for a particular application and suppressing other wavelengths, such as ambient light and / or sunlight. In yet another embodiment, the term "light-transmitting" may be used for applications in which any useful light, such as the emission wavelengths from an underlying LED, may pass through the material. The terms transparent, reflective, and light-transmitting may be defined with respect to a particular wavelength range, such as that emitted by an LED chip and / or converted by any light-emitting material. The specific values ​​listed above are intended to describe average values ​​or properties of an element or layer. It is understood that variations in these properties may exist within or throughout such elements or layers.

[0030]

[0058] As used herein, the term "opaque" refers, inter alia, to materials, surfaces, and particles that are not transparent or non-transparent across at least a portion of the visible light spectrum. In certain embodiments, the term "opaque" can also apply to the entire visible light spectrum. The term "non-transparent" can be thought of as transmitting less than 20%, or less than 10%, of the received light, or of specific wavelengths of received light. Materials can be made more opaque by either light absorption or light reflection. Some materials are opaque at certain wavelengths and transparent at other wavelengths. As a non-limiting example, a red pigment can function as a color filter by absorbing light wavelengths less than about 600 nm, becoming opaque, and transmitting light wavelengths greater than about 600 nm, becoming transparent. A layer can contain a distribution of opaque material in an amount that allows the layer to maintain light transmission.

[0031]

[0059] The present invention can be useful for LED chips having various geometries, such as lateral geometries. Lateral geometry LED chips typically include both anode and cathode electrical connections on the same side of the LED chip, opposite a substrate such as a growth substrate. In certain embodiments, lateral geometry LED chips can be flip-chip mounted such that the anode and cathode connections are on the face of the active LED structure opposite the primary emission face of the LED chip. In this configuration, electrical traces or patterns can be provided on the mounting surface to provide electrical connections to the anode and cathode connections of the LED chip. In a flip-chip configuration, the active LED structure is configured between the substrate and mounting surface of the LED chip. Thus, light emitted from the active LED structure can pass through the substrate in a desired emission direction.

[0032]

[0060] As described herein, the principles of the present disclosure are applicable to various embodiments with LED chips of various sizes, including not only large-area chips, but also small LED chips and micro LED chips. As used herein, large-area LED chips may have lateral dimensions of up to about 2000 microns (μm), while small LED chips may have lateral dimensions of about 100 μm, and micro LED chips may have lateral dimensions of less than 50 μm. Thus, LED chips of the present disclosure may have lateral dimensions in the range of 20 μm to 2000 μm, or in the range of 20 μm to 1000 μm, or in the range of 20 μm to 100 μm, or in the range of 100 μm to 2000 μm, depending on the application.

[0033]

[0061] According to aspects of the present disclosure, an LED package may include one or more elements provided with one or more LED chips, such as a light-emitting material, an encapsulant, a light-modifying material, a lens, a superstrate or support element, an adhesive element, and electrical contacts, among others. A light-modifying material may be disposed inside the LED package to reflect or otherwise redirect light from one or more LED chips in a desired emission direction or pattern. The term "superstrate" is used herein in part to refer to a support element in an LED device to avoid confusion with other conventional substrates or submounts that may traditionally be part of an LED device, such as a growth substrate or carrier substrate for an LED chip and / or a submount for an LED package. The term "superstrate" is not intended to limit the orientation, position, and / or configuration of the structure it describes, nor the various optical, electrical, thermal, and mechanical properties beyond those of the support element as described herein. In certain embodiments, the superstrate may be composed of a transparent, translucent, or optically transmissive material to the various wavelengths of light provided by the LED chip and / or light-emitting material.

[0034]

[0062] As used herein, light-modifying materials can include many different materials, including light-reflective materials that reflect or redirect light, light-absorbing materials that absorb light, and materials that act as thixotropic agents. As used herein, the term "light-reflective" refers to materials or particles that reflect, refract, scatter, or otherwise redirect light. In the case of light-reflective materials, the light-modifying material can include at least one of fused silica, fumed silica, titanium dioxide (TiO), zirconium oxide (ZrO), aluminum oxide (AlO), metal particles, glass fiber, and / or glass particles suspended in a binder such as silicone or epoxy. In certain aspects, the particles can have a refractive index configured to refract light emission in a desired direction. In certain aspects, light-reflective particles can also be referred to as light-scattering particles. In the case of light-absorbing materials, the light-modifying material may include at least one of carbon, silicon, metal, metal oxide (e.g., iron oxide, etc.), and organic particles suspended in a binder such as silicone or epoxy. Exemplary organic particles may include various pigments, dyes, and / or absorbing additives. Thixotropic materials may include one or more of glass fillers and fumed silica. Light-reflective and light-absorbing materials may comprise nanoparticles. In certain embodiments, the light-modifying material may comprise a generally white color to reflect and redirect light. In other embodiments, the light-modifying material may comprise a generally opaque color, such as black or gray, to absorb light and enhance contrast. In certain embodiments, the light-modifying material includes both a light-reflective material and a light-absorbing material suspended in a binder. As used herein, one or more layers or coatings of light-modifying material may be referred to as a light-modifying coating. In certain embodiments, the light-modifying material or coating may be free of a luminescent material. Light modifying elements may also refer to modified surfaces that do not necessarily require the addition of particles, such as textures used for diffusion and / or scattering.In yet another embodiment, the light-modifying material may be provided in the form of a coating that is applied to the exterior or surface of a light-emitting device to control light emission.

[0035]

[0063] In certain applications, it is desirable to increase the speed at which LED devices can be manufactured. One approach to increasing manufacturing speed is to assemble multiple components on a single support element (or superstrate, as described below) and later divide the group into component arrays. This can be particularly useful when creating multicolor component arrays for use in high-definition (HD) video displays. Multiple arrays can be created as large sheets and then singulated into individual arrays with multiple LED devices for each singulated portion. In this way, a single LED device, after singulation, can include multiple LED chips of different emitting colors, such as red, green, and blue, among others. In this regard, such LED devices may be well suited for use as pixels within HD video displays and / or signage applications. In other embodiments, larger arrays of LED chips can be formed together to provide LED components, LED tiles, LED screens, and / or LED displays.

[0036]

[0064] Additionally, eliminating various elements of conventional LED devices may streamline the manufacturing process, improve light quality, facilitate device miniaturization, and / or reduce costs. For example, LED devices can be assembled without or without conventional LED package submounts (e.g., ceramic submounts with traces, lead frame structures, printed circuit boards, etc.). This can be achieved by assembling the LEDs top-down, i.e., the LEDs are assembled on a support element, such as a transparent superstrate or light-transmitting layer, that will become the top exterior surface of the finished product. These components can then be electrically connected through exposed electrical connection points on the opposite side of the LED. As such, a device or apparatus may lack a conventional submount, e.g., a ceramic, metal, or other type of rigid material substrate to which LEDs are often attached, on the side of the LED opposite the light-transmitting side. An LED device constructed top-down as described herein can be considered a complete LED device without such a rigid submount. This does not mean that such LED devices cannot be later assembled into larger (e.g., multi-component) devices, which may include, for example, conventional package submounts.

[0037]

[0065] While such a single LED device containing densely packed LED chips of multiple colors may be well-suited for use as pixels within HD video displays and / or signage applications, challenges exist with the near-field and / or far-field emission patterns from such devices. For example, inconsistent far-field emission patterns provided by different LED chips (e.g., red, blue, and green LED chips) within a single package can cause the appearance of color shifts when a video display is viewed at various angles. Emission variations can arise both from different emission patterns for the different color chips and from their geometric arrangement within the LED package. As another example, near-field emission is typically concentrated along the center of the LED device from densely packed LED chips, contributing to a more pixelated appearance and reduced fill factor within video screens and displays. In this regard, when multiple LED devices with centrally concentrated near-field emission patterns are assembled together, a so-called "screen door" effect may be visible when dark lines are formed by the columns and rows along the boundaries of the LED devices within the display.

[0038]

[0066] Support elements according to the present disclosure provide improved far-field light emission patterns for improved uniformity at wider viewing angles within a display, and / or improved near-field light emission uniformity by increasing the fill factor within each LED device, thereby reducing the screen door effect within the display. The support element may include a laminate structure with a transparent superstrate and / or light-transmitting layer, and any number of materials and optical structures that exhibit light-transmitting and / or light-scattering properties for the associated LEDs and / or light-emitting materials. In certain embodiments, the support element may include a laminate structure of various layers or sublayers configured to improve the near-field and / or far-field light emission patterns, particularly in the case of a light-emitting device with multiple chips emitting light at multiple peak wavelengths. The laminate film may generally be light-transmitting to light from the corresponding LED chips, while also exhibiting one or more of light reflection, light refraction, light absorption, light scattering, and / or light-diffusion properties. In certain embodiments, an exemplary support element may include a light-transmitting layer sandwiched between two layers that have enhanced light-reflecting, light-refracting, light-absorbing, light-scattering, and / or light-diffusing properties relative to the light-transmitting layer. In this regard, the centrally located light-transmitting layer may form a light-mixing chamber, where light may propagate laterally and internally reflect several times along the support element before finally exiting the LED device with enhanced light emission uniformity. As used herein, the internal mixing chamber within the support element may also be referred to as an optical cavity.

[0039]

[0067] FIG. 1 shows a mounting surface 14 of a support element 14. M1 is a cross-sectional view of an LED device 10 including multiple LED chips 12-1 to 12-2 mounted on a substrate. For illustrative purposes, only two LED chips 12-1 to 12-2 are illustrated. However, depending on the embodiment, the LED chips 12-1 to 12-2 may include any number of LED chips configured to emit light of the same or different wavelengths. For example, for a display application in which the LED device 10 forms a display pixel, three LED chips configured to emit blue, green, and red light may be provided. Depending on the application, other color combinations, including white light emission, may be provided. Depending on the application, the LED chips 12-1 to 12-2 may have various lateral dimensions, such as in the range of 20 μm to 2000 μm, or in the range of 20 μm to 1000 μm, or in the range of 20 μm to 1000 μm, or in the range of 20 μm to 1000 μm. Small LED chips (eg, about 100 μm to 300 μm + / - 50 μm) and micro LED chips (eg, less than 100 μm) may be well suited for pixels in LED displays.

[0040]

[0068] The LED chips 12-1 to 12-2 are mounted on a mounting surface 14 of the support element 14. MThe LED chips 12-1 to 12-2 may be mounted to the support element 14 via a die-attach layer 16, which may be continuous or discontinuous throughout. The die-attach layer 16 may be optically transparent to the wavelengths of light generated by the LED chips 12-1 to 12-2; exemplary materials include silicone and / or epoxy. After the LED chips 12-1 to 12-2 are adhered to the support element 14 via the die-attach layer 16, an encapsulation layer 18 may be applied around the perimeter of, and optionally between, the LED chips 12-1 to 12-2. The encapsulation layer 18 may be applied by one or more of dispensing, molding, stenciling, screen printing, spinning, spraying, powder coating, or slit coating. The encapsulating layer 18 may comprise one or more electrically insulating materials, such as epoxy, epoxy-polyester hybrid, aliphatic urethane, triglycidyl isocyanurate (TGIC) polyester, non-TGIC polyester, silicone, silicone-modified polyester, silicone hybrid, silicone-epoxy hybrid, acrylic, polycarbonate, or any suitable combination thereof. In certain embodiments, the encapsulating layer 18 may comprise a light-modifying material used to control the light output of the LED device 10. For example, the encapsulating layer 18 may comprise a light-reflective and / or light-refractive material that redirects light from the LED chips 12-1 to 12-2, or even a light-absorbing material that enhances contrast. Certain light-reflective and / or light-refractive materials may exhibit a white appearance, while light-absorbing materials may exhibit a dark or even black appearance. In certain embodiments, the encapsulation layer 18 may include structures designed to enhance mechanical strength or other fillers designed to control the coefficient of thermal expansion (CTE).

[0041]

[0069] The electrical connections for the LED chips 12-1 to 12-2 may be provided on the side of the LED chips 12-1 to 12-2 opposite the support element 14. In other words, the LED chips 12-1 to 12-2 may be disposed between the support element 14 and the electrical connections for the LED chips 12-1 to 12-2. In this manner, at least a portion of the light from the LED chips 12-1 to 12-2 may pass through the support element 14 without interacting with the electrical connections. The electrical connections may include device contact pads 20 electrically connected to one or more of the LED chips 12-1 to 12-2 via conductive paths 22, which may include, but are not limited to, conductive pedestals, bump bonds, solder materials, wires, traces, and vias comprising metals such as gold (Au) and / or copper (Cu). The different conductive paths 22 may be coupled to corresponding ones of the chip contact pads 24. The device contact pads 20 may include a single layer or multiple layers, depending on the arrangement and / or manufacturing sequence. Multiple conductive traces 26-1, 26-2 and insulating layers 28-1, 28-2 may further be used to route the electrical connections between the device contact pads 20 and the chip contact pads 24. In certain embodiments, the conductive traces 26-1, 26-2 may embody patterned metal traces. For example, the conductive trace 26-1 may be patterned so that segments thereof are electrically coupled to one or more of the LED chips 12-1 to 12-2 and further extend through portions of the encapsulation layer 18. In certain embodiments, the conductive traces 26-1, 26-2, insulating layers 28-1, 28-2, and various conductive paths 22 may form a fan-out circuit structure. In yet other embodiments, the conductive traces 26-1, 26-2, insulating layers 28-1, 28-2, and various conductive paths 22 may be formed at the wafer level or panel level before the individual LED devices 10 are singulated.

[0042]

[0070] The arrangement of the LED chips 12-1 to 12-2 relative to the support element 14 is such that light 30 exiting the LED device 10 from the LED chips 12-1 to 12-2 passes through the support element 14 and reaches the mounting surface 14 M The main light-emitting surface 14 opposite E For illustrative purposes, light 30 is provided so as to be able to exit from primary light emitting surface 14. E The illustrated arrows of light 30 are not intended to accurately represent a specific light direction as in a ray trace diagram, but are intended to represent a specific direction of light, away from the primary light emitting surface 14. E In an arrangement in which support element 14 is substantially transparent to light 30, light 30 emitted from LED device 10 is directed through primary light emitting surface 14 aligned with LED chips 12-1 to 12-2. E In this way, LED device 10 can not only reduce color shift and uniformity of the far-field light emission pattern, but also increase the near-field bright spot, which reduces the fill factor in an LED display.

[0043]

[0071] FIG. 2 is a cross-sectional view of an LED device 32 similar to the LED device 10 of FIG. 1 , except that the support element 14 further includes a diffusing material 34 therein. In this manner, the support element 14 may diffuse and / or scatter the light 30 from the LED chips 12-1 to 12-2. However, for certain applications, such as LED display applications, the thickness of the support element 14 is typically thin, small, or reduced to maintain an overall low profile for the LED device 32. In this regard, the presence of the diffusing material 34 alone throughout the support element 14 may not be sufficient to substantially affect the near-field and far-field emission patterns of the light 30 exiting the LED device 32. While adding the diffusing material 34 above the LED chips 12-1 to 12-2 is common, it may have minimal desired effects on light uniformity, as suggested by the lack of change in the arrows of the light 30 between FIG. 2 and FIG. 1 . This effect is particularly minimal when the thickness of the diffusing material 34 is thin.

[0044]

[0072] FIG. 3 is a cross-sectional view of an LED device 36 similar to the LED device 10 of FIG. 1 , except that the support element 14 includes a light-transmitting layer 38 and a light-diffusing layer 40. Thus, the support element 14 of the LED device 36 incorporates features of both the LED device 10 of FIG. 1 and the LED device 32 of FIG. 2 . As illustrated, the light-transmitting layer 38 is provided with a thickness substantially greater than the light-diffusing layer 40, or for that matter, any other element of the LED device 36, to ensure an adequate propagation length for mixing of the light 30 from the LED chips 12-1 to 12-2. In this regard, the light-diffusing layer 40 is spaced a greater distance from the output surfaces of the LED chips 12-1 to 12-2, thereby allowing the light 30 from the LED chips 12-1 to 12-2 propagating at various output angles through the light-transmitting layer 38 to reach the light-diffusing layer 40 and pass through with high uniformity. While such an arrangement may advantageously improve near-field and far-field emission patterns, the increased thickness of the LED device 36 from the thick light-transmitting layer 38 may not be suitable for certain low-profile applications, such as LED displays, or for certain manufacturing processes, as singulation of high aspect ratio devices may be difficult.

[0045]

[0073] FIG. 4 is a cross-sectional view of an LED device 42, an improvement over the LED device 36 of FIG. 3 , in which the support element 14 includes a multi-layer structure that forms an internal mixing chamber to improve near-field and far-field emission while maintaining a low profile for the LED device 42. In certain embodiments, the support element 14 may include a first light-diffusing layer 40-1 and a second light-diffusing layer 40-2 on opposite sides of the light-transmitting layer 38. During operation, light emitted from the LED chips 12-1 to 12-2 may be initially scattered as it passes through the first light-diffusing layer 40-1 and enters the light-transmitting layer 38. The scattered light within the light-transmitting layer 38 may be scattered a second time upon interacting with the second light-diffusing layer 40-2. Such a structure provides a scattering interface on the opposite side of the light-transmitting layer 38 at the interface with the light-diffusing layers 40-1 and 40-2, and the light-transmitting layer 38 may form an internal mixing chamber bounded by the scattering interface within the support element 14. In this way, the light emitted within the light-transmitting layer 38 may be scattered multiple times at interfaces with the light-diffusing layers 40-1, 40-2 before exiting the LED device 42, which causes more light emission to spread laterally within the light-transmitting layer 38. Therefore, the light 30 exiting the LED device 42 may exhibit improved near-field and far-field emission patterns.

[0046]

[0074] In certain embodiments, the light-transmitting layer 38 may comprise glass, sapphire, epoxy, or other rigid material that is optically transparent to the wavelengths of light generated by the LED chips 12-1 to 12-2. The light-diffusing layers 40-1, 40-2 may comprise light-diffusing particles dispersed within the light-transmitting material, such as particles with a high refractive index, or particles with a refractive index different from that of the surrounding medium, or visible white pigments. As used herein, light-diffusing particles may include any of the light-reflecting and / or light-refractive particles described above with respect to the light-modifying material. The light-diffusing layers 40-1, 40-2 may also comprise roughened and / or textured surfaces formed, for example, by etching. In certain embodiments, the light-transmitting layer 38 and the light-diffusing layers 40-1, 40-2 may comprise the same material, such as glass, with the light-diffusing layers 40-1, 40-2 further comprising light-diffusing particles added to the material to form the light-diffusing layers 40-1, 40-2. In other embodiments, the light diffusing layers 40-1, 40-2 may comprise other materials, such as sol-gel, spin-on glass, and / or sintered glass frit with light diffusing particles dispersed therein.

[0047]

[0075] By forming an internal mixing chamber within the support element 14, improved light emission can be achieved while maintaining a low profile for the LED device 42. As used herein, low profile refers to the distance from the device contact pads 20 to the primary light-emitting surface 14. EThis may refer to a relative dimension in which the height or thickness of the LED device 42, measured from the edge of the support element 14, is less than or equal to the lateral width of the LED device 42, measured from the opposing periphery of the support element 14. By way of example, the overall dimensions of the LED device 42 may include the above-described height and width being 1000 microns (μm) or less, or 500 μm or less, or in the range of 200 μm to 1000 μm, or in the range of 200 μm to 500 μm. To achieve such dimensions, the light diffusing layers 40-1, 40-2 and the light transmitting layer 38 may each have a thickness in the range of 50 μm to 200 μm, or in the range of 25 μm to 200 μm, or in the range of 20 μm to 200 μm. In yet another embodiment, the above-described height and width may be in the range of 10 μm to 1000 μm, or in the range of 10 μm to 2000 μm.

[0048]

[0076] FIG. 5 is a cross-sectional view of an LED device 44 similar to the LED device 42 of FIG. 4 for an embodiment in which the support element 14 further includes a light-absorbing layer 46. In certain embodiments, the light-absorbing layer 46 may be configured to be optically transparent to a majority of the light 30 while also providing sufficient light-absorbing properties to enhance contrast. For example, the light-absorbing layer 46 may be configured to reduce the appearance of a white color underlying the light-diffusing layers 40-1, 40-2 at wide viewing angles. In certain embodiments, the light-absorbing layer 46 may comprise the same base material as the light-diffusing layers 40-1, 40-2 with light-absorbing particles, such as black particles, instead of white particles. In yet another embodiment, the light-absorbing particles may be dispersed in the light-diffusing layer 40-2, and a separate light-absorbing layer 46 may be omitted.

[0049]

[0077] FIG. 6 is a cross-sectional view of an LED device 48 similar to the LED device 42 of FIG. 4, except that the support element 14 includes first and second light-reflecting layers 50-1, 50-2 on opposite sides of the light-transmitting layer 38. In this regard, the internal mixing chamber of the light-transmitting layer 38 is bounded by a reflective interface with the first and second light-reflecting layers 50-1, 50-2. The first and second light-reflecting layers 50-1, 50-2 may include thin layers or coatings of reflective material that are generally optically transparent to the light emitted from the LED chips 12-1 to 12-2. In this regard, some light may pass through the first and second light-reflecting layers 50-1, 50-2, while other portions of the light may be reflected. Thus, the first and second light-reflecting layers 50-1, 50-2 may provide a function similar to the light-diffusing layers 40-1, 40-2 of FIG. 4. In certain embodiments, the first and second light-reflecting layers 50-1, 50-2 may each embody a metal layer having a thickness of 50 nm or less, or in the range of 2 nm to 50 nm. In other embodiments, the thickness may be greater than 50 nm or less than 100 nm. In certain embodiments, the first and second light-reflecting layers 50-1, 50-2 comprise a thin layer of metal or dielectric reflector, including a single dielectric layer or a stack of multiple dielectric layers.

[0050]

[0078] FIG. 7 is a cross-sectional view of an LED device 52 similar to the LED device 42 of FIG. 4, except that the support element 14 includes a light-transmitting layer 38 between a first light-modifying layer 54-1 and a second light-modifying layer 54-2 that is different from the first light-modifying layer 54-1. For example, the second light-modifying layer 54-2 may be configured to exhibit a higher light transmittance than the first light-modifying layer 54-1. In this manner, light 30 propagating and / or scattering within the light-transmitting layer 38 may preferentially pass through the second light-modifying layer 54-2 and exit the LED device 52 in a desired light emission direction. Therefore, a reduced amount of light 30 may pass through the first light-modifying layer 54-1 and return toward the LED chips 12-1, 12-2, and such emission may be sensitive to absorption. In other embodiments, the order may be reversed, with the first light-modifying layer 54-1 configured to exhibit a higher light transmittance than the second light-modifying layer 54-2, promoting increased spreading and / or recycling of light within the light-transmitting layer 38 before exiting the LED device 52.

[0051]

[0079] 7, first light modifying layer 54-1 and second light modifying layer 54-2 may both comprise light-reflecting layers 50-1, 50-2, as described above for FIG. 6, except that first light modifying layer 54-1 may be configured to be more reflective of the peak wavelength of light from LED chips 12-1 to 12-2 than second light modifying layer 54-2. For example, first light modifying layer 54-1 may comprise a different reflective material than second light modifying layer 54-2. In another example, both first and second light modifying layers 54-1, 54-2 may comprise the same material, and second light modifying layer 54-2 may be formed with a reduced thickness compared to first light modifying layer 54-1 to enhance light transmittance.

[0052]

[0080] 7, first light modifying layer 54-1 and second light modifying layer 54-2 may both comprise light diffusing layers 40-1, 40-2, as described above for FIG. 4, except that first light modifying layer 54-1 may be configured to diffuse more light from LED chip 12-1-12-2 than second light modifying layer 54-2. For example, first light modifying layer 54-1 may be loaded with a higher density of light diffusing particles than second light modifying layer 54-2, and / or second light modifying layer 54-2 may be formed with a thinner thickness compared to first light modifying layer 54-1 to provide improved light transmittance.

[0053]

[0081] 7, first light modifying layer 54-1 may comprise light reflecting layer 50-1 as described above for FIG. 6, and second light modifying layer 54-2 may comprise light diffusing layer 40-2 as described above for FIG. 4. In this manner, first light modifying layer 54-1 may embody a thin layer of reflective material that allows sufficient light to pass from LED chips 12-1 to 12-2 to light transmitting layer 38 while simultaneously limiting the amount of light within light transmitting layer 38 that propagates back to LED chips 12-1 to 12-2. Second light modifying layer 54-2 may be reflective to the primary light-emitting surface 14 of support element 14. E This can serve to further diffuse the light emitted from the

[0054]

[0082] FIG. 8 is a cross-sectional view of an alternative configuration of support element 14 of FIG. 7 for an embodiment in which first and second light modifying layers 54-1, 54-2 are filled with pores 56, or air pockets and / or bubbles, to promote increased light scattering. In this regard, the majority of first and second light modifying layers 54-1, 54-2 may comprise a light-transmitting material, such as a glass or ceramic material, with pores 56 dispersed therein to provide light-diffusing properties. In certain embodiments, each of first and second light modifying layers 54-1, 54-2 and light-transmitting layer 38 may comprise the same material, such as a ceramic material, glass, spin-on glass, or sintered glass frit. In other embodiments, one or more of first and second light modifying layers 54-1, 54-2 and light-transmitting layer 38 may comprise different materials from one another. For example, light transmissive layer 38 may comprise sapphire, and first and second light modifying layers 54-1, 54-2 may comprise another ceramic, such as aluminum oxide, with some porosity. For glass frit embodiments, the laminate structure of first and second light modifying layers 54-1, 54-2 and light transmissive layer 38 may be sintered together, and the size and / or density of pores 56 may be controlled by selection of frit particle size and / or pressure of the laminate structure.

[0055]

[0083] FIG. 9 is a cross-sectional view of an alternative configuration of support element 14 of FIG. 7 for an embodiment in which first and second light modifying layers 54-1, 54-2 are filled with oxide particles 58 having a shape and / or particle size distribution or a medium with a different refractive index value to promote increased light scattering. In this regard, the majority of first and second light modifying layers 54-1, 54-2 may comprise a light-transmitting material, such as a glass or ceramic material, and oxide particles 58 may be dispersed therein to provide light-diffusing properties. With respect to the configuration of FIG. 8, each of first and second light modifying layers 54-1, 54-2 and light-transmitting layer 38 may comprise the same material, such as a ceramic material, glass, spin-on glass, or sintered glass frit. In other embodiments, one or more of first and second light modifying layers 54-1, 54-2 and light-transmitting layer 38 may comprise different materials from each other. For example, the light-transmitting layer 38 may comprise sapphire, and the first and second light-modifying layers 54-1, 54-2 may comprise another ceramic, such as aluminum oxide, having oxide particles 58. For glass frit embodiments, the laminate structure of the first and second light-modifying layers 54-1, 54-2 and the light-transmitting layer 38 may be sintered together. The size and / or density of the oxide particles 58 may be controlled by selecting the size or distribution of the frit particles and / or controlling the sintering time, which may cause some glass to precipitate from the oxide particles 58 within the first and second light-modifying layers 54-1, 54-2. In another embodiment, the size and / or density of the oxide particles 58 may be controlled by adding an oxide precursor material that is loaded within the first and second light-modifying layers 54-1, 54-2 prior to sintering. In yet another embodiment, the oxide particles 58 as illustrated in FIG. 9 may represent any medium that provides a different refractive index value than the light-transmitting layer 38 and the bulk of the first and second light-modifying layers 54-1, 54-2.

[0056]

[0084] In certain embodiments, the support element 14 may be formed by a co-fired or sintered laminate structure, as described above with respect to any of FIGS. 4 through 9 . The laminate structure may include optically transparent materials, such as aluminum oxide, sapphire, glass, spin-on glass, or ceramics, including sintered glass frit, in the light-transmitting and / or light-modifying layers described above. Light-diffusing particles, pores, oxide particles, and reflective layers may be used as light-modifying layers to define the boundaries of an internal light-mixing chamber between which light circulates. Light inside the mixing chamber may thus be diffused laterally before exiting, thereby improving near-field and far-field emission patterns. In certain embodiments, such benefits may be realized due to thin dimensions, in which the overall device height is equal to or less than the overall device width. Both the support element 14 and associated LED devices described above may be advantageously formed at the wafer level prior to individual device singulation. 4-9 may be well suited to providing improved near-field and far-field emission when the LED device includes multiple LED chips of multiple colors. For example, a first LED chip may be configured to provide a first peak wavelength in the range of 430 nm to 480 nm, a second LED chip may be configured to provide a second peak wavelength in the range of 500 nm to 570 nm, and a third LED chip may be configured to provide a third peak wavelength in the range of 600 nm to 700 nm or in the range of 600 nm to 750 nm. Other embodiments may include one or more LED chips providing UV wavelengths or wavelength ranges as described above.

[0057]

[0085] Additionally, while support element 14 is generally illustrated above as a three-layer structure, it should be recognized that support element 14 can include any number of layers within the scope of the present disclosure. For example, individual layers of light-diffusing layers 40-1, 40-2, light-reflecting layers 50-1, 50-2, and light-modifying layers 54-1, 54-2 may embody a multi-layer structure. The principles disclosed herein relate to increasing the lateral spread of light by recycling light through support element 14 while increasing reflection and / or diffusion (e.g., specular or diffuse reflection) from upper and lower regions or layers. These regions or layers can be anything from very thin (e.g., metal mirrors) to thick. These regions or layers can be uniform within themselves, have graduated contours, or be composed of multiple semi-uniform layers, as illustrated herein. In yet another embodiment, the individual layers of support element 14 described above with respect to any of Figures 4 through 9 can be repeated to form multiple stacked mixing chambers within a single support element 14.

[0058]

[0086] As explained above, the LED devices of the present disclosure are well suited for use as pixels in LED display applications. In such applications, it is desirable to further improve the light fill factor within each LED device to reduce the pixelated appearance of the display, especially when viewed at close range. In certain LED devices, the LED chip area within the LED device is typically much smaller than the overall device footprint, which can provide higher-intensity light emission in the center of the LED device and contribute to a screen-door effect when arranged as pixels in lines and columns within a display. According to further embodiments of the present disclosure, additional configurations of optical structures are disclosed that include a light-transmitting layer and one or more patterned light-modifying layers to further promote lateral spreading of light within each LED device. One or more patterned light-modifying layers can be provided to redistribute higher light intensity laterally within the LED device, thereby reducing or even masking the light output associated with bright spots that would otherwise exist directly above the LED chips.

[0059]

[0087] FIG. 10 is an exploded view of a generic LED device 60 similar to LED device 42 of FIG. 4 , with at least one light-modifying layer 54 patterned to tailor the light emission pattern from LED device 60. LED device 60 may include one or more of LED chips 12-1 to 12-2, as illustrated. Light-modifying layer 54 may embody a patterned or segmented layer similar to any of the light-diffusing layers 40-1, 40-2 described above for FIG. 4 and / or the light-reflecting layers 50-1, 50-2 described above for FIG. 6 . As with the previous embodiment, LED device 60 may include any number of LED chips, including embodiments having red, blue, and green LED chips. In FIG. 10 , a base structure 62 is schematically shown below LED chips 12-1 to 12-2. If present, base structure 62 may provide primary support for LED chips 12-1 to 12-2 and other elements of LED device 60. In this regard, the support element 14 may represent an additional layer formed on and / or supported by the base structure 62. The base structure 62 may include any of the conductive traces 26-1, 26-2, insulating layers 28-1, 28-2, device contact pads 20, chip contact pads 24, and conductive paths 22, as described and illustrated in FIGS. 1 through 7 . The base structure 62 may also embody one of many base structures known in the art, such as a lead frame-based plastic leaded chip carrier (PLCC). In such cases, other elements not shown in FIG. 10 are contemplated, such as reflectors that redirect light along the sides of the LED device 60 to areas such as the light-transmitting layer 38. In the case of a PLCC device, such a reflector typically comprises a white plastic housing that houses a portion of the leads.

[0060]

[0088] As illustrated in FIG. 10 , light-modifying layer 54 is patterned so as not to completely cover light-transmitting layer 38. The pattern may include several discontinuous segments of light-modifying layer 54. Alternatively, the pattern may include continuous or connected segments of light-modifying layer 54, with various openings distributed across the surface area of ​​light-modifying layer 54. The pattern may be implemented by a selective deposition or selective removal process. In other embodiments, the pattern may be provided by a molding or even embossing process, in which features are formed in a host material and then filled with light-modifying material. The size of the individual features of light-modifying layer 54 within the pattern may be nanoscale, such as in the range of 10 nm to 900 nm. The pattern of light-modifying layer 54 causes at least some light from LED chips 12-1, 12-2 to be redirected by light-modifying layer 54 to specific regions. In other regions that do not include portions of light-modifying layer 54, light may pass more freely. In certain embodiments, such a pattern of light modifying layer 54 may be positioned to avoid the appearance of a bright spot located in the center of LED device 60, thereby increasing the light fill factor. For example, portions of light modifying layer 54 may be vertically aligned with LED chips 12-1 to 12-2 to reduce and / or redirect light from LED chips 12-1 to 12-2 away from the center of LED device 60. As used herein, vertical alignment may be defined as an arrangement in which a vertical line intersects two elements. For example, a first vertical line passing through LED chip 12-1 and a second vertical line passing through LED chip 12-2 both intersect a portion of light modifying layer 54. In certain embodiments, other portions or segments of light modifying layer 54 may be positioned in other areas other than directly above LED chips 12-1 to 12-2 to further align the light emission pattern. In certain embodiments, light absorbing layer 46 may be provided on light modifying layer 54 and / or light transmitting layer 38.

[0061]

[0089] FIG. 11A is a cross-sectional view of an LED device 64 similar to the LED device 60 of FIG. 10, including first and second light-modifying layers 54-1, 54-2 on opposite sides of the light-transmitting layer 38. In FIG. 11A, the second light-modifying layer 54-2 above the light-transmitting layer 38 is patterned relative to the LED chips 12-1, 12-2, while the first light-modifying layer 54-1 continuously covers the light-transmitting layer 38. In this manner, as light 30 propagates within the light-transmitting layer 38, such light 30 can more easily pass through the second light-modifying layer 54-2, which is patterned with a desired light emission distribution. However, it is understood that the order can be reversed to pattern the first light-modifying layer 54-1 to provide a different light emission pattern. This pattern creates localized mixing chambers that promote localized light recycling throughout the portion of the support element 14 bounded by the first and second light-modifying layers 54-1, 54-2.

[0062]

[0090] As illustrated in FIG. 11A , the central segment of the second light modifying layer 54-2 is vertically aligned above the LED chips 12-1, 12-2. In certain embodiments, the segment of the second light modifying layer 54-2 includes an area large enough to extend laterally beyond the periphery of the LED chips 12-1, 12-2. The second light modifying layer 54-2 may further include segments positioned closer to the periphery of the LED device 64 to further tailor the light emission pattern. If present, the light absorbing layer 46 may be disposed over the segment of the second light modifying layer 54-2 and, optionally, over portions of the light-transmitting layer 38 that are between the segments or portions of the second light modifying layer 54-2. In certain embodiments, the pattern of the light absorbing layer 46 may be the same as that of the second light modifying layer 54-2, while in other embodiments, the light absorbing layer 46 may have an inverse pattern to that of the second light modifying layer 54-2.

[0063]

[0091] FIG. 11B is an exemplary top view of the LED device 64 of FIG. 11A. As illustrated, a central segment of the second light modifying layer 54-2 is centrally disposed, while several smaller segments of the second light modifying layer 54-2 are radially inset from the periphery of the LED device 64. In this regard, some of the light from the LED chips 12-1, 12-2 of FIG. 11A may be redirected laterally away from the center of the LED device 64 toward the periphery, and such light may be further redirected laterally at various local locations near the periphery. In the context of LED devices 64 forming pixels in an LED display, the placement of the second light modifying layer 54-2 may reduce and / or suppress the direct visibility of the underlying LED chips 12-1 to 12-2 of FIG. 11A.

[0064]

[0092] FIG. 12 is a cross-sectional view of an LED device 66 similar to LED device 64 of FIGS. 11A and 11B , in which first light modifying layer 54-1 is also patterned. Thus, both first and second light modifying layers 54-1, 54-2 may be patterned on opposite sides of light-transmitting layer 38. In certain embodiments, the pattern of second light modifying layer 54-2 is similar to FIG. 11A , but an additional pattern of first light modifying layer 54-1 is provided. For example, first light modifying layer 54-1 may be formed in segments laterally spaced from LED chips 12-1, 12-2, thereby forming openings in first light modifying layer 54-1 vertically aligned with LED chips 12-1, 12-2 and allowing an increased amount of light to enter light-transmitting layer 38. Such an arrangement may be particularly suitable for embodiments in which first light modifying layer 54-1 comprises a layer with a higher reflectivity compared to second light modifying layer 54-2. In this way, light can pass freely from the LED chips 12-1, 12-2 into the light-transmitting layer 38, while light propagating laterally within the light-transmitting layer 38 can be reflected toward the desired light emission direction. As explained above, the pattern of the light-absorbing layer 46 can be the same as or the inverse of the second light-modifying layer 54-2.

[0065]

[0093] FIG. 13 is a cross-sectional view of an LED device 68 similar to the LED device 66 of FIG. 12 , in which the first light-modifying layer 54-1 is patterned with segments aligned with the LED chips 12-1, 12-2 to block direct light emission from the LED chips 12-1, 12-2. As illustrated, the segments of the first light-modifying layer 54-1 may be disposed between the top surfaces of the LED chips 12-1, 12-2 and the light-transmitting layer 38, thereby redirecting light emission from the LED chips 12-1, 12-2 laterally before entering the light-transmitting layer 38. In this manner, bright spots associated with the locations of the LED chips 12-1, 12-2 in the light 30 exiting the LED device 68 may be reduced. As further illustrated in FIG. 13 , the segments of the second light-modifying layer 54-2 need not completely cover the LED chips 12-1, 12-2, but may be dispersed throughout the light-transmitting layer 38. In such an arrangement, one or more of die attach layer 16 and encapsulant 18 may be at least partially light-transmitting and function as a laterally extending layer through which light propagates away from LED chips 12-1 to 12-2 before passing through light-transmitting layer 38. If die attach layer 16 sufficiently covers the surface area of ​​light-transmitting layer 38 adjacent LED chips 12-1 to 12-2, encapsulant 18 may be configured to enhance reflectivity, such as by including white reflective particles. As discussed above, the pattern of light-absorbing layer 46 may be the same as or the reverse of second light-modifying layer 54-2.

[0066]

[0094] FIG. 14 is a cross-sectional view of an LED device 70 similar to LED device 66 of FIG. 12 for an embodiment in which the pattern of the first light modifying layer 54-1 is the inverse of the pattern of the second light modifying layer 54-2. As illustrated, the inverse pattern provides an arrangement in which segments of the first light modifying layer 54-1 are vertically aligned with openings in the second light modifying layer 54-2. In this manner, variations in the amount of light passing through each of the first and second light modifying layers 54-1, 54-2 can be offset, improving overall light emission uniformity. As explained above, the pattern of the light absorbing layer 46 can be the same as or the inverse of the pattern of the second light modifying layer 54-2.

[0067]

[0095] Figure 15 is a cross-sectional view of an LED device 72 similar to LED device 70 of Figure 14 for an embodiment in which the pattern of the first light modifying layer 54-1 is the same as the pattern of the second light modifying layer 54-2. As illustrated, the same pattern provides an arrangement in which the segments of the first light modifying layer 54-1 are vertically aligned with the segments of the second light modifying layer 54-2. In this manner, the openings in the first and second light modifying layers 54-1, 54-2 can be aligned to combine increased light emission along the LED device 72. As explained above, the pattern of the light absorbing layer 46 can be the same as or the inverse of the pattern of the second light modifying layer 54-2.

[0068]

[0096] 16 through 24 illustrate various patterns of second light modifying layer 54-2 for LED chips 12-1 through 12-3 that can provide improved near-field and far-field light emission uniformity in accordance with aspects of the present disclosure. First light modifying layer 54-1 may be omitted or provided in any of the arrangements illustrated in FIGS. 11A, 12, and 13. In further embodiments, first light modifying layer 54-1 may be provided in an inverse pattern to second light modifying layer 54-2 in FIGS. 18 through 24, similar to that described above for FIG. 14. In other embodiments, first light modifying layer 54-1 may be provided in the same pattern as second light modifying layer 54-2 in FIGS. 18 through 24, similar to that described above for FIG. 15. Various patterns of second light modifying layer 54-2 may include segments of various shapes, including squares, rectangles, triangles, circles, ellipses, other shapes, and combinations thereof. The various patterns may also be arranged in more random or noisy patterns, such as Gaussian noise distributions, to reduce the effects of optical interference, especially when the structure sizes are smaller. The illustrations are conceptual and are not intended to illustrate the relative sizes of the various patterns, LED chips 12-1 to 12-3, and the overall LED device. While the size of the patterns may range anywhere from submicron to the size of the corresponding LED device, the LED chips 12-1 to 12-3 are typically large micrometers, exceeding 100 μm. In each of FIGS. 16 through 24, the footprints of the LED chips 12-1 to 12-3 are indicated by superimposed dashed boxes.

[0069]

[0097] 16 illustrates a top view of an LED device 74 for an embodiment in which the second light modifying layer 54-2 is disposed in a checkerboard pattern across the LED device 74. Thus, the openings in the second light modifying layer 54-2 are evenly distributed across the LED device 74, improving uniformity. In certain embodiments, the checkerboard nature of the pattern may provide connecting corners for segments of the second light modifying layer 54-2.

[0070]

[0098] Figure 17 is a top view of an LED device 76 similar to LED device 74 of Figure 16 for an embodiment in which the segments of second light modifying layer 54-2 vary in size along the LED device 76. For example, the pattern of segments of second light modifying layer 54-2 may alternate between smaller surface area segments and larger surface area segments across the LED device 76. In particular, only the smaller surface area segments may be located closest to the periphery of the LED device 76, where light emission may be reduced in conventional devices.

[0071]

[0099] FIG. 18 is a top view of an LED device 78 similar to LED device 74 of FIG. 16 for an embodiment in which segments of second light modifying layer 54-2 are discontinuously formed throughout LED device 78. In this manner, the surface area of ​​LED device 78 free of second light modifying layer 54-2 is increased compared to FIG. 16. Such an arrangement may be beneficial for reducing any appearance of a pattern in second light modifying layer 54-2 depending on the brightness levels of LED chips 12-1 to 12-3. In other embodiments, the illustrated pattern for second light modifying layer 54-2 may be inverted, with the shaded squares representing holes or openings in second light modifying layer 54-2.

[0072]

[0100] FIG. 19 is a top view of an LED device 80 similar to LED device 74 of FIG. 16 for an embodiment in which the shape and / or size of segments of second light modifying layer 54-2 vary throughout the LED device 80. For example, a larger rectangular segment of second light modifying layer 54-2 may be positioned to cover the area of ​​LED chips 12-1 to 12-3, thereby masking their appearance and reducing the higher direct emission intensity in the center of LED device 80. In addition, other segments of second light modifying layer 54-2 may be positioned around the larger rectangular segment. Such additional segments may be arranged in circles or other rounded shapes to reduce instances of sharp corners in second light modifying layer 54-2 and improve the uniformity of the light emission. In other embodiments, the illustrated circle pattern for second light modifying layer 54-2 may be inverted so that the shaded circles represent holes or openings in second light modifying layer 54-2. In yet other embodiments, many other patterns of second light modifying layer 54-2 that serve similar purposes are contemplated. For example, the central rectangle of second light modifying layer 54-2 aligned with LED chips 12-1 to 12-3 may be replaced with a checkerboard-like pattern having small openings through it.

[0073]

[0101] 20 is a top view of an LED device 82 similar to LED device 80 of FIG. 19 for an embodiment in which the density of the segments of second light modifying layer 54-2 varies throughout LED device 82. For example, the segments of second light modifying layer 54-2 can be densely arranged in the areas corresponding to LED chips 12-1 to 12-3 to at least partially mask their appearance and reduce the higher emission intensity in the center of LED device 82. In other embodiments, the illustrated circle pattern for second light modifying layer 54-2 can be inverted so that the shaded circles represent holes or openings in second light modifying layer 54-2.

[0074]

[0102] 21 is a top view of an LED device 84 similar to LED device 74 of FIG. 16 for an embodiment in which the pattern includes a single segment of second light modifying layer 54-2 aligned with LED chips 12-1 through 12-3. As illustrated, the segment of second light modifying layer 54-2 may cover a larger portion of LED device 84 that, in conventional devices, is centrally located and typically associated with a bright light-emitting point. In this regard, second light modifying layer 54-2 may reduce central emission while redirecting other emission laterally away from near the periphery of LED device 84.

[0075]

[0103] Figure 22 is a top view of an LED device 86 similar to LED device 84 of Figure 21, in which a single segment of second light modifying layer 54-2 is provided in a band that traverses between two opposing peripheries of LED device 84. In certain embodiments, the single segment of second light modifying layer 54-2 may traverse completely between two opposing peripheries.

[0076]

[0104] Figure 23 is a top view of an LED device 88 similar to LED device 86 of Figure 22 in which a single segment of second light modifying layer 54-2 is provided with a surface area corresponding to the combined surface area or footprint of LED chips 12-1 to 12-3. In this regard, second light modifying layer 54-2 may mask the appearance of LED chips 12-1 to 12-3 and / or reduce the emission intensity in a central portion of LED device 88 without occupying a large area of ​​LED device 88.

[0077]

[0105] Figure 24 is a top view of an LED device 90 similar to LED device 88 of Figure 22, except that second light modifying layer 54-2 forms a pattern having individual segments, each segment aligned or otherwise matched with the footprint of a corresponding individual one of LED chips 12-1 through 12-3. As with Figure 23, such an arrangement may mask the appearance of LED chips 12-1 through 12-3 and / or reduce the emission intensity in a central portion of LED device 90 without occupying a large area of ​​LED device 90.

[0078]

[0106] It is understood that the above-described patterns in second light modifying layer 54-2 can have a transmittance of 0% or close to 0%, thereby effectively blocking and redirecting all incident light, or any intermediate transmittance percentage, whereby some light is redirected while other portions of light are allowed to pass. Additionally, the boundaries or pattern edges of second light modifying layer 54-2 can be graduated from one amount or shade of transmittance to another, thereby having what are called "soft" edges.

[0079]

[0107] As previously explained, the base structure 62 of any of the aforementioned embodiments of FIGS. 10 through 24 can embody a variety of structures, such as an insulating submount with conductive traces or a leadframe structure including a PLCC LED package. FIG. 25A is an exploded cross-sectional view of a generic LED device 92, similar to the LED device 60 of FIG. 10, for an embodiment in which the base structure 62 is a leadframe structure. In this regard, the base structure 62 includes a leadframe 94 and a corresponding housing 96. The leadframe 94 provides electrical connections to the LED chips 12-1 to 12-2, which in some cases are mounted on one portion of the leadframe 94 and wirebonded to another portion of the leadframe 94. For illustrative purposes, the wirebonds are generally depicted in FIG. 25A as curved lines connecting the LED chips 12-1 to 12-2 to one portion of the leadframe 94. It will be understood that other wirebonding arrangements may also be implemented. In other configurations, one or more of the LED chips 12-1 to 12-2 may be flip-chip mounted to the lead frame 94 without the need for wire bonding. The housing 96 may include a recess having sidewalls in which the LED chips 12-1 to 12-2 reside. In certain embodiments, the sidewalls of the housing 96 may be beveled. The light-transmitting layer 38 may be formed to fit within the recess of the housing 96, or the light-transmitting layer 38 may be formed within the recess to conform to the shape of the recess. The light-modifying layer 54 and the optional light-absorbing layer 46 may be provided as described above. One or more portions of the light-modifying layer 54 and one or more of the light-absorbing layers 46 generally conform to the shape of the light-transmitting layer 38 and may be planar, convex, concave, or lens-shaped. FIG. 25B is an assembled cross-sectional view of the LED package 92 of FIG. 25A.

[0080]

[0108] In certain embodiments, the light-modifying layer of the present disclosure may embody an anodized metal layer, such as anodized aluminum oxide. Anodization is an electrochemical process that forms a metal oxide layer on a metal surface. In the case of aluminum, anodization forms an aluminum oxide layer or film on the surface of the aluminum body. In certain embodiments, the aluminum oxide layer of anodized aluminum may be formed with a porous structure. If the anodized aluminum oxide is thin enough, the porous structure may be able to allow light to pass through. Other portions of the porous structure may be filled with pigment and then sealed to provide other optical properties for the LED device. For example, black pigment or a hue may be applied to certain areas to provide localized light absorption properties as described above.

[0081]

[0109] 26A and 26B are partially exploded cross-sectional views of a generic LED device 98 similar to LED device 60 of FIG. 10 for an embodiment in which light-modifying layer 54 includes an anodized metal structure, such as anodized aluminum. FIG. 26A illustrates light-modifying layer 54 before anodization, and FIG. 26B illustrates light-modifying layer 54 after anodization. LED device 98 may include LED chips 12-1 to 12-2, light-transmitting layer 38, and base structure 62, as previously described. Light-modifying layer 54 may include a patterned metal layer 100 provided in a manner similar to any of the patterns of light-modifying layer 54 illustrated in the previous embodiment. As illustrated in FIG. 26B, an upper portion of patterned metal layer 100 may form a metal oxide 100′ after anodization. In addition, the sidewall surface of patterned metal layer 100 may have an anodized surface. As illustrated, the patterned metal layer, which is an anodized metal layer, may be formed with localized regions having different thicknesses. In certain embodiments, the metal oxide layer 100' may be dyed with a light-absorbing pigment or color, such as a black pigment, to provide various light-emitting tuning properties, such as a top matte finish, for improved contrast. The bottom of the patterned metal layer 100 has unoxidized metal portions, which may improve the light reflectance of light passing through the light-transmitting layer 38.

[0082]

[0110] As illustrated in FIG. 26A , the light-modifying layer 54 may further include several optional layers that aid in the anodization process. For example, an additional metal layer 102 and / or a current-spreading layer 104 may be formed between the patterned metal layer 100 and the light-transmitting layer 38 to allow current to flow to various regions as needed during the anodization process. The current-spreading layer 104 may be electrically conductive and at least partially optically transparent to light from the LED chips 12-1 to 12-2. As illustrated in FIG. 26B , the additional metal layer 102 may also be anodized during the anodization process to form a metal oxide 102′. If sufficiently thin, the porosity of the metal oxide 102′ may provide an optical path for light to travel between the patterned metal layer 100 and the additional metal layer 102. In certain embodiments, both the patterned metal layer 100 and the additional metal layer 102 comprise aluminum. The current spreading layer 104 may comprise, among other things, indium tin oxide, which may maintain electrical conductivity and thereby facilitate complete anodization of the additional metal layer 102. In this manner, the metal oxide 102' of the additional metal layer 102 may be formed with increased porosity such that the metal oxide 102' is optically transparent, or even optically transmissive.

[0083]

[0111] In other embodiments, the additional metal layer 102 and / or current spreading layer 104 may be omitted. In such embodiments, the patterned metal layer 100 with metal oxide 100′ may be formed by blanket metal deposition, such as evaporation or sputtering, followed by anodization, after which the anodized structure may be further patterned. In either case, the anodization process and / or the thickness of the patterned metal layer 100, with or without the additional metal layer 102 and / or current spreading layer 104, may be tailored to tune the optical properties of the light-modifying layer 54.

[0084]

[0112] 26A and 26B are provided in the context of light-modifying layer 54 being provided on a side of light-transmitting layer 38 farther from LED chips 12-1 to 12-2, it is contemplated that an anodized metal layer may also be provided on a side of light-transmitting layer 38 closest to LED chips 12-1 to 12-2. For example, as illustrated with respect to FIG. 12, one or more of light-modifying layers 54-1, 54-2 may embody an anodized metal layer.

[0085]

[0113] It is contemplated that any of the foregoing aspects, and / or various individual aspects and features as described herein, may be combined to further advantage. Any of the various embodiments as disclosed herein may be combined with one or more of the other disclosed embodiments, unless indicated to the contrary herein.

[0086]

[0114] 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 herein and the following claims.

Claims

1. 1. A light emitting diode (LED) device comprising: one or more LED chips; a support element on which the one or more LED chips are mounted, the support element configured to be optically transparent to wavelengths of light generated by the one or more LED chips, the support element comprising an internal mixing chamber that spreads light laterally within the support element.

2. 10. The LED device of claim 1, wherein the internal mixing chamber is formed by a light-transmitting layer between a first light-diffusing layer and a second light-diffusing layer.

3. 3. The LED device of claim 2, wherein at least one of the first light-diffusing layer and the second light-diffusing layer comprises a multi-layer structure.

4. 3. The LED device of claim 2, wherein the light-transmitting layer comprises glass, and the first and second light-diffusing layers comprise glass with light-diffusing particles.

5. 5. The LED device of claim 4, wherein the light-diffusing particles comprise particles having a different refractive index than the glass.

6. 3. The LED device of claim 2, wherein the light-transmitting layer, the first light-diffusing layer, and the second light-diffusing layer each have a thickness in the range of 20 microns (μm) to 200 μm.

7. 3. The LED device of claim 2, wherein the support element further comprises a light absorbing layer on the second light diffusing layer.

8. 10. The LED device of claim 8, wherein the light-absorbing layer comprises light-diffusing particles dispersed within a light-transmitting material.

9. 10. The LED device of claim 1, wherein the one or more LED chips are mounted on a mounting surface of the support element, an opposite surface of the support element forming a primary light emitting surface of the LED device.

10. 10. The LED device of claim 9, further comprising contact pads on a side of the one or more LED chips opposite the support element, wherein a height of the LED device measured from the contact pads to the primary light-emitting surface is less than or equal to a width of the support element measured between opposing peripheries of the support element.

11. 11. The LED device of claim 10, wherein the height and the width are in the range of 200 microns ([mu]m) to 1000 [mu]m.

12. 10. The LED device of claim 1, wherein the internal mixing chamber is formed by a light-transmitting layer between a first light-reflecting layer and a second light-reflecting layer.

13. 13. The LED device of claim 12, wherein the first light-reflecting layer and the second light-reflecting layer each have a thickness of 0.05 microns (μm) or less.

14. 10. The LED device of claim 1, wherein the one or more LED chips comprise: a first LED chip configured to provide a first peak wavelength in a range of 430 nanometers (nm) to 480 nm; a second LED chip configured to provide a second peak wavelength in a range of 500 nm to 570 nm; and a third LED chip configured to provide a third peak wavelength in a range of 600 nm to 700 nm.

15. 10. The LED device of claim 1, wherein the internal mixing chamber is one of a plurality of internal mixing chambers stacked within the support element.

16. 1. A light emitting diode (LED) device comprising: one or more LED chips; a support element on which the one or more LED chips are mounted, the support element configured to be optically transparent to wavelengths of light generated by the one or more LED chips, the support element comprising a light-transmitting layer between first and second light-modifying layers.

17. 17. The LED device of claim 16, wherein the first light modifying layer is closer to the one or more LED chips than the second light modifying layer.

18. 18. The LED device of claim 17, wherein the first light modifying layer comprises a first light reflecting layer and the second light modifying layer comprises a second light reflecting layer, the first light reflecting layer having a different reflectivity than the second light reflecting layer for peak wavelengths of light from the one or more LED chips.

19. 20. The LED device of claim 17, wherein the first light modifying layer comprises a first light diffusing layer and the second light modifying layer comprises a second light diffusing layer, the first light diffusing layer diffusing the light from the one or more LED chips in a different manner than the second light diffusing layer.

20. 20. The LED device of claim 17, wherein one of the first and second light modifying layers comprises a light reflecting layer and the other of the first and second light modifying layers comprises a light diffusing layer.

21. 17. The LED device of claim 16, wherein one or more of the first light modifying layer and the second light modifying layer comprises pores dispersed within a bulk material.

22. 17. The LED device of claim 16, wherein one or more of the first light modifying layer and the second light modifying layer comprises oxide particles dispersed within a bulk material.

23. 17. The LED device of claim 16, wherein the light-transmitting layer forms an internal light-mixing chamber bounded by the first light-modifying layer and the second light-modifying layer.

24. 24. The LED device of claim 23, wherein the internal mixing chamber is one of a plurality of internal mixing chambers stacked within the support element.

25. 17. The LED device of claim 16, wherein the one or more LED chips comprise: a first LED chip configured to provide a first peak wavelength in a range of 430 nanometers (nm) to 480 nm; a second LED chip configured to provide a second peak wavelength in a range of 500 nm to 570 nm; and a third LED chip configured to provide a third peak wavelength in a range of 600 nm to 700 nm.

26. 17. The LED device of claim 16, wherein at least one of the first light modifying layer and the second light modifying layer comprises a multi-layer structure.

27. 1. A light emitting diode (LED) device comprising: one or more LED chips; a light-transmitting layer on the one or more LED chips; a light modifying layer disposed in the pattern of the light transmitting layer, the light transmitting layer being between the light modifying layer and the one or more LED chips.

28. 30. The LED device of claim 27, wherein the light modifying layer comprises one or more of a light diffusing layer, a light scattering layer, and a light reflecting layer.

29. 30. The LED device of claim 28, wherein the light modifying layer comprises the light diffusing layer, the light diffusing layer comprising light diffusing particles dispersed within a light-transmitting material or textured surface.

30. 30. The LED device of claim 28, wherein the light-modifying layer comprises the light-reflecting layer, the light-reflecting layer having a thickness that is less than or equal to 100 nanometers (nm).

31. 30. The LED device of claim 28 further comprising a light absorbing layer over the light modifying layer and over portions of the light transmitting layer between portions of the light modifying layer.

32. 30. The LED device of claim 27, wherein the pattern comprises discontinuous segments of the light modifying layer.

33. 30. The LED device of claim 27, wherein the pattern comprises connected segments of the light modifying layer.

34. 30. The LED device of claim 27, wherein the pattern comprises segments of the light modifying layer aligned with the one or more LED chips.

35. 28. The LED device of claim 27, wherein the one or more LED chips comprise: a first LED chip configured to provide a first peak wavelength in a range of 430 nanometers (nm) to 480 nm; a second LED chip configured to provide a second peak wavelength in a range of 500 nm to 570 nm; and a third LED chip configured to provide a third peak wavelength in a range of 600 nm to 750 nm.

36. 30. The LED device of claim 27, further comprising a base structure on which the one or more LED chips are mounted, the base structure comprising an insulating submount with conductive traces or a leadframe structure.

37. 30. The LED device of claim 27, wherein the light-modifying layer comprises at least one anodized metal layer.

38. 38. The LED device of claim 37, further comprising a current spreading layer between the at least one anodized metal layer and the one or more LED chips.

39. 38. The LED device of claim 37, wherein the at least one anodized metal layer comprises a light-absorbing pigment.

40. 38. The LED device of claim 37, wherein the at least one anodized metal layer comprises localized regions having different thicknesses.

41. 28. The LED device of claim 27, wherein the pattern is a molded pattern or an embossed pattern.

42. 30. The LED device of claim 27, wherein the pattern comprises individual features having sizes ranging from 10 nm to 900 nm.

43. 1. A light emitting diode (LED) device comprising: one or more LED chips; a first light-modifying layer on the one or more LED chips; a second light modifying layer on the first light modifying layer, the first light modifying layer being closer to the one or more LED chips than the second light modifying layer; and a light-transmitting layer between a first light-modifying layer and the second light-modifying layer, wherein at least one of the first light-modifying layer and the second light-modifying layer is disposed on the light-transmitting layer in a pattern.

44. 44. The LED device of claim 43, wherein the first light modifying layer and the second light modifying layer each comprise a light diffusing layer or a light reflecting layer.

45. 44. The LED device of claim 43, wherein the pattern comprises one or more segments of the second light-modifying layer.

46. 46. ​​The LED device of claim 45, wherein the first light modifying layer is arranged in an additive pattern comprising one or more segments of the first light modifying layer.

47. 47. The LED device of claim 46, wherein the one or more segments of the first light modifying layer are laterally spaced from the one or more LED chips to form openings in the first light modifying layer aligned with the one or more LED chips.

48. 47. The LED device of claim 46, wherein the one or more segments of the first light modifying layer are disposed between the one or more LED chips and the light-transmitting layer, and the one or more segments of the first light modifying layer are aligned with the one or more LED chips.

49. 47. The LED device of claim 46, wherein the one or more segments of the first light modifying layer are arranged in an inverse pattern to the one or more segments of the second light modifying layer.

50. 47. The LED device of claim 46, wherein the one or more segments of the first light modifying layer are arranged in the same pattern as the one or more segments of the second light modifying layer.

51. 46. ​​The LED device of claim 45, wherein the one or more segments of the second light-modifying layer form a checkerboard-like pattern.

52. 46. ​​The LED device of claim 45, wherein the one or more segments of the second light-modifying layer comprise alternating segments of varying surface area or shape.

53. 46. ​​The LED device of claim 45, wherein the one or more segments of the second light-modifying layer comprise a first segment disposed over the one or more LED chips and a plurality of second segments disposed around the first segment.

54. 46. ​​The LED device of claim 45, wherein the one or more segments of the second light modifying layer comprise a plurality of segments that vary in density across the LED device.

55. 44. The LED device of claim 43, wherein at least one of the first light modifying layer and the second light modifying layer comprises an anodized metal layer.

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