Reflector for support structure in light emitting diode package

Abstract

Solid state lighting devices including light emitting diodes (LEDs), and more particularly, include a reflector for a support structure in an LED package (48). The support structure includes an arrangement of dielectric reflectors (18) relative to conductive traces (14) and LED chips (36) patterned on the submount (12). The dielectric reflector includes a plurality of dielectric layer structures that form a distributed Bragg reflector (DBR) or in some cases an aperiodic Bragg reflector. Such dielectric reflectors (18) may be disposed on one or more conductive traces (14) and on portions of the submount (12) that are not covered by the conductive traces to provide increased reflectance over various wavelengths provided by the LED chip, including wavelengths in the ultraviolet (UV) spectrum. Each disclosed LED package (34, 42, 44, 46, 48, 50, 52, 54, 56, 60, 62, 64) is also provided with a cover structure (38).

Description

Technical Field

[0001] The present disclosure relates to solid state lighting devices including light emitting diodes (LEDs), and more particularly to reflectors for support structures in LED packages. Background Art

[0002] Solid-state lighting devices, such as light emitting diodes (LEDs), are increasingly used in consumer and commercial applications. Advances in LED technology have produced highly efficient and mechanically robust light sources with long service lives. As a result, modern LEDs have enabled a variety of new display applications and are increasingly being used in a wide range of lighting applications, often replacing incandescent and fluorescent light sources.

[0003] An LED is a solid-state device that converts electrical energy into light, and typically includes one or more active layers (or active regions) of semiconductor material arranged between relatively doped n-type and p-type layers. When a bias is applied to the doped layers, holes and electrons are injected into the active layer or layers, where they recombine to produce emission, such as visible or ultraviolet light. An LED chip typically includes an active region, which may be made of, for example, silicon carbide, gallium nitride, gallium phosphide, aluminum nitride, gallium arsenide-based materials, and / or from organic semiconductor materials. Photons generated by the active region are emitted in all directions.

[0004] Generally, it is desirable to operate an LED at the highest possible luminous efficiency, which can be measured by emission intensity with respect to output power (e.g., in lumens / watt). A practical goal of improving emission efficiency is to maximize the extraction of light emitted from the active region in the direction of desired light transmission. Light extraction and external quantum efficiency of an LED may be limited by a variety of factors, including internal reflections. LED packages have been developed that can provide mechanical support, electrical connections, and packaging for LED emitters. Light emission from the surface of the LED emitter can then interact with elements or surfaces of the corresponding LED package, thereby increasing the chance of light loss. In addition, the wavelength of the emitted light and various operating conditions can cause degradation of various materials traditionally used for LED packaging. Therefore, there may be challenges in producing high quality light with desired emission characteristics while also providing high light emission efficiency in an LED package.

[0005] The art continues to seek improved LEDs and solid state lighting devices having desirable lighting characteristics that overcome challenges associated with conventional lighting devices. Summary of the invention

[0006] The present disclosure relates to solid-state lighting devices including light-emitting diodes (LEDs), and more particularly to reflectors for support structures in LED packages. The support structure includes an arrangement of dielectric reflectors relative to conductive traces and LED chips patterned on a base. The dielectric reflectors include a plurality of dielectric layer structures that form a distributed Bragg reflector or, in some cases, a non-periodic Bragg reflector. Such dielectric reflectors can be arranged on one or more conductive traces and on portions of the base not covered by the conductive traces to provide increased reflectivity at various wavelengths provided by the LED chip, including wavelengths in the ultraviolet spectrum.

[0007] In one aspect, an LED package includes: a base including a first face and a second face opposite the first face; at least one LED chip on the first face of the base; a cover structure disposed over the at least one LED chip; a patterned trace on the first face of the base, the cover structure attached to the patterned trace at a cover structure mounting area outside of at least one die attach pad; and a dielectric reflector on a portion between at least one die attach pad of the patterned trace and the cover structure mounting area, the dielectric reflector comprising a distributed Bragg reflector. In a specific embodiment, the distributed Bragg reflector is a non-periodic distributed Bragg reflector. In a specific embodiment, the non-periodic distributed Bragg reflector includes a plurality of dielectric layers; and each dielectric layer of the plurality of dielectric layers includes a unique optical thickness relative to other dielectric layers of the plurality of dielectric layers. In a specific embodiment, the plurality of dielectric layers include alternating dielectric layers of a first material type and a second material type. In a specific embodiment, the dielectric reflector is also on a portion of the base not covered by the patterned trace and the at least one LED chip. In a particular embodiment, a dielectric reflector is further disposed in a gap between the at least one LED chip and the submount formed by the patterned trace along the at least one die attach pad. In a particular embodiment, the at least one LED chip is configured to provide a peak wavelength in a range from 200 nm to 400 nm.

[0008] In another aspect, an LED package includes: a base including a first face and a second face opposite the first face; at least one LED chip on the first face of the base; a cover structure disposed over the at least one LED chip, the cover structure being mounted to the base at a cover structure mounting region spaced apart from a peripheral boundary of the at least one LED chip; a patterned trace on the first face of the base, the patterned trace forming at least one die attach pad for the at least one LED chip; and a dielectric reflector on a portion of the base laterally adjacent to the patterned trace, the dielectric reflector comprising a distributed Bragg reflector. In a specific embodiment, the dielectric reflector is also disposed on a portion of the patterned trace. In a specific embodiment, the dielectric reflector is also disposed between the cover structure and the base at the cover structure mounting region. In a specific embodiment, the distributed Bragg reflector is a non-periodic distributed Bragg reflector; the non-periodic distributed Bragg reflector includes a plurality of dielectric layers; and each dielectric layer of the plurality of dielectric layers includes a unique optical thickness relative to other dielectric layers of the plurality of dielectric layers. In a specific embodiment, the plurality of dielectric layers include alternating dielectric layers of a first material type and a second material type. In a particular embodiment, a dielectric layer having a maximum optical thickness among the plurality of dielectric layers is positioned to be spaced apart from a top surface of the non-periodic distributed Bragg reflector and inside the non-periodic distributed Bragg reflector. In a particular embodiment, at least one LED chip is configured to provide a peak wavelength in a range from 200 nm to 400 nm.

[0009] On the other hand, an LED package includes: a base including a first face and a second face opposite the first face; at least one LED chip on the first face of the base; a patterned trace on the first face of the base; and a dielectric reflector, on a portion of the patterned trace and on a portion of the base laterally adjacent to the patterned trace, the dielectric reflector including a distributed Bragg reflector. In a specific embodiment, the distributed Bragg reflector is a non-periodic distributed Bragg reflector. In a specific embodiment, the non-periodic distributed Bragg reflector includes a plurality of dielectric layers; and each dielectric layer in the plurality of dielectric layers includes a unique optical thickness relative to other dielectric layers of the plurality of dielectric layers. In a specific embodiment, the plurality of dielectric layers include alternating dielectric layers of a first material type and a second material type. In a specific embodiment, the dielectric layer having the largest optical thickness among the plurality of dielectric layers is positioned to be spaced apart from the top surface of the non-periodic distributed Bragg reflector and inside the non-periodic distributed Bragg reflector. In a particular embodiment, the patterned trace includes at least one die attach pad for at least one LED chip; and the dielectric reflector is also arranged in a gap formed by the patterned trace along the at least one die attach pad between the at least one LED chip and the base. In a particular embodiment, the at least one LED chip is configured to provide a peak wavelength in the range from 200 nm to 400 nm. The LED package may also include a cover structure arranged on the base to form a cavity on the at least one LED chip. The LED package may also include a reflector structure arranged between the cover structure and the base, wherein the sidewalls of the reflector structure define a portion of the cavity. In a particular embodiment, the dielectric reflector is arranged on the sidewalls of the reflector structure. In a particular embodiment, the dielectric reflector is arranged between the reflector structure and the base.

[0010] On the other hand, any of the aforementioned aspects, independently or together, and / or as described herein, different individual aspects and features can be combined for additional advantage. Unless otherwise indicated herein, any of the various features and elements disclosed herein can be combined with one or more other disclosed features and elements.

[0011] Those skilled in the art will understand the scope of the present disclosure and appreciate additional aspects thereof after reading the following detailed description of the preferred embodiments in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] 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.

[0013] Figure 1is a top view of a portion of a light emitting diode (LED) package including a portion of a first patterned trace (collectively referred to herein as the first patterned trace) disposed on a submount and a dielectric reflector according to principles of the present disclosure.

[0014] Figure 2 is with Figure 1 A top view of a portion of an LED package similar to an LED package with an alternative layout for a dielectric reflector.

[0015] Figure 3 is a cross-sectional view of an exemplary dielectric reflector that may be provided for any embodiment of the present disclosure.

[0016] Figure 4A is a cross-sectional view of a structure including a first patterned trace and a dielectric reflector.

[0017] Figure 4B is a cross-sectional view of a structure for an alternative arrangement of first patterned traces and dielectric reflectors.

[0018] Figure 5A According to the principles of the present disclosure, Figure 1 The cross-sectional view of the LED package is similar to that of a portion of the LED package taken along section line AA, wherein the LED package is assembled with at least one LED chip and a cover structure.

[0019] Figure 5B is along with Figure 1 The cross-sectional line BB is similar to a portion of the LED package cut in the area outside the LED chip. Figure 5A Cross-sectional view of an LED package.

[0020] Fig. 6A is an alternative arrangement with a covering structure similar to Figure 5A and Figure 5B A cross-sectional view of an LED package.

[0021] Figure 6B is along with Figure 1 The cross-sectional line BB is similar to a portion of the LED package cut in the area outside the LED chip. Fig. 6A Cross-sectional view of an LED package.

[0022] Fig. 7A is along with Figure 1 Section line AA is similar to a cross-sectional view of a portion of the LED package taken along section line AA, and wherein the dielectric reflector is disposed between the cover structure and the base in the cover structure mounting region.

[0023] Figure 7B is along with Figure 1 The cross-section line BB is similar to that of a portion of an LED package taken Fig. 7A Cross-sectional view of an LED package.

[0024] Fig. 8A is with Fig. 6A and Figure 6B An LED package is similar to a cross-sectional view of an LED package, and wherein a dielectric reflector is disposed between the cover structure and the base in a cover structure mounting area.

[0025] Figure 8B is along with Figure 1 The cross-sectional line BB is similar to a portion of the LED package cut in the area outside the LED chip. Fig. 8A Cross-sectional view of an LED package.

[0026] Fig. 9 is with Figure 5A An LED package is similar to a cross-sectional view of an LED package, and wherein the dielectric reflector is further disposed on a portion of the base that is laterally adjacent to the first patterned trace.

[0027] Fig.10 is with Fig. 7A An LED package is similar to a cross-sectional view of an LED package, and wherein the dielectric reflector is further disposed on a portion of the base that is laterally adjacent to the first patterned trace.

[0028] Fig.11 is along with Figure 1 Section line AA is similar to a cross-sectional view of a portion of the LED package taken similarly to that of the LED package, and wherein the first patterned trace is not provided in the cover structure mounting area.

[0029] Fig.12 is with Fig.11 An LED package is a cross-sectional view of a similar LED package, except that the dielectric reflector is not positioned within the cover structure mounting area.

[0030] Fig.13 is along with Figure 1 The cross-sectional view of the LED package is similar to that of a portion of the LED package taken along section line AA, and wherein the LED package includes a reflector structure arranged between the cover structure and the base.

[0031] Fig.14 is with Fig.13 An LED package similar to FIG. 1 is a cross-sectional view of an LED package of FIG. 1 and wherein the dielectric reflector extends on the first patterned trace in a position between the reflector structure and the base.

[0032] Fig.15 is with Fig.13 FIG. 1 is a cross-sectional view of an LED package similar to an LED package and wherein the dielectric reflector extends along the sidewalls of the reflector structure.

[0033] Fig.16 is with Fig.15 An LED package is similar to a cross-sectional view of an LED package of FIG. 1 , and wherein the dielectric reflector extends along a sidewall of the reflector structure and between the reflector structure and the first patterned trace. DETAILED DESCRIPTION

[0034] The embodiment of the following explanation represents the necessary information that enables those skilled in the art to practice the embodiment, and shows the best mode of practicing the embodiment. When reading the following description according to the accompanying drawings, those skilled in the art will understand the concept of the present disclosure, and will recognize that these concepts are not specifically addressed in this article. It should be understood that these concepts and applications fall within the scope of the present disclosure and the appended claims.

[0035] It should be understood that, although the terms first, second, etc. may be used in this article to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the present disclosure, the first element may be referred to as the second element, and similarly, the second element may be referred to as the first element. As used in this article, the term "and / or" includes any and all combinations of one or more related listed items.

[0036] It should be understood that when an element such as a layer, region or substrate is referred to as being "on" or extending to another element "on", the element may be directly on or directly extended to another element, or there may also be an intermediate element. On the contrary, when an element is referred to as "directly on" another element or "directly extending to another element", there is no intermediate element. Similarly, it should be understood that when an element such as a layer, region or substrate is referred to as "on" another element "above" or "extending" "above" another element, the element may be directly on or directly above another element, or there may also be an intermediate element. On the contrary, when an element is referred to as "directly above" or "directly above" another element, there is no intermediate element. It should also be understood that when an element is referred to as "connected" or "coupled" to another element, the element may be directly connected or coupled to another element, or there may be an intermediate element. On the contrary, when an element is referred to as "directly connected" or "directly coupled" to another element, there is no intermediate element.

[0037] Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe the relationship of one element, layer or region to another element, layer or region as shown in the figures. It should be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the figures.

[0038] The terms used herein are used only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that when used herein, the terms "comprises", "comprising", "includes", and / or "including" specify the presence of the features, wholes, steps, operations, elements, and / or parts, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, parts, and / or combinations thereof.

[0039] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. It should also be understood that, unless explicitly defined as such herein, the terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art, and should not be interpreted in an idealized or overly formal sense.

[0040] Embodiments are described herein with reference to schematic diagrams of embodiments of the present disclosure. Therefore, the actual sizes of layers and elements may be different, and due to factors such as manufacturing technology and / or tolerances, it is foreseeable that there will be deviations from the illustrated shapes. For example, the area illustrated or described as a square or rectangle may have circular or curved features, and the area shown as a straight line may have some irregularities. Therefore, the areas shown in the drawings are schematic, and their shapes are not intended to illustrate the precise shape of the area of ​​the device, and are not intended to limit the scope of the present disclosure. In addition, for the purpose of illustration, the size of a structure or area may be enlarged relative to other structures or areas, and therefore, it is provided to illustrate the general structure of the subject matter and may or may not be drawn to scale. Common elements between the drawings may be shown in this article with common element numbers, and may not be repeated subsequently.

[0041] The present disclosure relates to solid-state lighting devices including light-emitting diodes (LEDs), and more particularly to reflectors for support structures in LED packages. The support structure includes an arrangement of dielectric reflectors relative to conductive traces and LED chips patterned on a base. The dielectric reflectors include a plurality of dielectric layer structures that form a distributed Bragg reflector or, in some cases, a non-periodic Bragg reflector. Such dielectric reflectors can be arranged on one or more conductive traces and on portions of the base not covered by the conductive traces to provide increased reflectivity at various wavelengths provided by the LED chip, including wavelengths in the ultraviolet spectrum.

[0042] Before exploring the specific details of various aspects of the present disclosure, an overview of the various elements that may be included in the exemplary LED package of the present disclosure is provided for context. The LED chip typically includes an active LED structure or region, which may have many different semiconductor layers arranged in different ways. The manufacture and operation of LEDs and their active structures are generally known in the art and are only briefly discussed here. The layers of the active LED structure can be manufactured using known processes, wherein a suitable process is manufactured using metal organic chemical vapor deposition. The layers of the active LED structure may include many different layers, and typically include an active layer sandwiched between n-type and p-type relatively doped epitaxial layers, all of which are continuously formed on a growth substrate. It should be understood that the active LED structure may also include additional layers and elements, including but not limited to buffer layers, nucleation layers, superlattice structures, undoped layers, cladding layers, contact layers, and current spreading layers and light extraction layers and elements. The active layer may include a single quantum well, a multiple quantum well, a double heterostructure, or a superlattice structure.

[0043] The active LED structure can be made from different material systems, some of which are based on Group III nitride material systems. Group III nitrides refer to those semiconductor compounds formed between nitrogen (N) and elements in Group III of the periodic table, typically aluminum (Al), gallium (Ga), and indium (In). Gallium nitride (GaN) is a common binary compound. 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). Other material systems include silicon carbide (SiC), organic semiconductor materials, and other Group III-V systems, such as gallium phosphide (GaP), gallium arsenide (GaAs), and related compounds.

[0044] The active LED structure can be grown on a growth substrate, which can include many materials, such as sapphire, SiC, aluminum nitride (AlN), and GaN. SiC has certain advantages, such as being more closely lattice-matched to III-nitrides than other substrates and producing high-quality III-nitride films. SiC also has very high thermal conductivity, so that the total output power of a III-nitride device 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, including low cost, mature manufacturing processes, and good light-transmitting optical properties.

[0045] Depending on the composition of the active layer and the n-type layer and the p-type layer, different embodiments of the active LED structure can emit light of different wavelengths. In some embodiments, the active LED structure emits blue light with a peak wavelength range of about 430 nanometers (nm) to 480nm. In other embodiments, the active LED structure emits green light with a peak wavelength range of 500nm to 570nm. In other embodiments, the active LED structure emits red light with a peak wavelength range of 600nm to 650nm. In a specific embodiment, the active LED structure can be configured to emit light outside the visible spectrum, including one or more parts of the UV spectrum. The UV spectrum is generally divided into three wavelength range categories represented by the letters A, B, and C. In this way, UV-A light is generally defined as a peak wavelength range from 315nm to 400nm, UV-B is generally defined as a peak wavelength range from 280nm to 315nm, and UV-C is generally defined as a peak wavelength range from 100nm to 280nm. UV LEDs are particularly suitable for applications related to microbial disinfection in air, water, and surfaces, etc. In other applications, UV LEDs may also be provided with one or more luminescent materials to provide LED packages with concentrated emission with a broad spectrum and improved color quality for visible light applications.

[0046] Light emitted by the active layer or region of the LED chip can typically propagate in multiple directions. For directional applications, internal reflectors or external reflective surfaces can be used to redirect as much light as possible toward the desired emission direction. The internal reflector can include a single layer or multiple layers. Some multilayer reflectors include a metal reflective layer and a dielectric reflective layer, wherein the dielectric reflective layer is arranged between the metal reflective layer and the multiple semiconductor layers. The passivation layer is arranged between the metal reflective layer and the first and second electrical contacts, wherein the first electrical contact is arranged to conduct electrical communication with the first semiconductor layer, and the second electrical contact is arranged to conduct electrical communication with the second semiconductor layer. For single or multilayer reflectors including a surface exhibiting a reflectivity of less than 100%, some light can be absorbed by the reflector. In addition, light redirected through the active LED structure can be absorbed by other layers or elements within the LED chip.

[0047] As used herein, a layer or region of a light emitting device may be considered "transparent" when at least 80% of the emitted radiation impinging on the layer or region is transmitted through the layer or region. In addition, as used herein, a layer or region of an LED is considered "reflective" or embodied as a "reflector" or "reflector" when at least 80% of the emitted radiation impinging on the layer or region is reflected. In some embodiments, the emitted radiation includes visible light, such as blue and / or green LEDs with or without luminescent materials. In other embodiments, the emitted radiation may include invisible light. For example, in the context of GaN-based blue and / or green LEDs, silver (Ag) may be considered a reflective material (e.g., at least 80% reflective). In the case of UV LEDs, appropriate materials may be selected to provide a desired, and in some embodiments high, reflectivity and / or a desired, and in some embodiments low absorptivity. In a particular embodiment, a "light-transmitting" material may be configured to transmit at least 50% of the emitted radiation of the desired wavelength.

[0048] The present disclosure can be useful for LED chips having a variety of geometries, including flip chip geometries. Flip chip structures for LED chips typically include anode and cathode connections made from the same side or face of the LED chip. The anode side and cathode side are typically configured as mounting surfaces for LED chips that are flip-chip mounted to another surface, such as a printed circuit board. In this regard, the anode and cathode connections on the mounting surface are used to mechanically join and electrically couple the LED chip to the other surface. When mounted in a flip chip manner, the opposite side or face of the LED chip corresponds to a light emitting surface oriented toward the intended emission direction. In particular embodiments, when mounted in a flip chip manner, the growth substrate of the LED chip can form the light emitting surface and / or be adjacent to the light emitting surface. During chip manufacturing, the active LED structure can be epitaxially grown on the growth substrate.

[0049] According to various aspects of the present disclosure, an LED package may include one or more elements arranged together with one or more LED chips, such as luminescent materials or phosphors for wavelength conversion, encapsulants, light-variable materials, lenses, and electrical contacts, etc. In certain aspects, the LED package may include a support member, such as a base or a lead frame. Light-variable materials may be arranged within the LED package to reflect or otherwise redirect light from one or more LED chips in a desired emission direction or pattern. As used herein, light-variable materials may 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.

[0050] Aspects of the present disclosure including support structures for LED packages are provided. A support structure may refer to a structure of an LED package that supports one or more other elements of an LED package, including but not limited to an LED chip and a cover structure. In a particular embodiment, the support structure may include a base on which the LED chip is mounted. Suitable materials for the base include but are not limited to ceramic materials (e.g., aluminum oxide or alumina), AlN, or organic insulators (e.g., polyimide (PI) and polyphthalamide (PPA)). In other embodiments, the base may include a printed circuit board (PCB), sapphire, Si, or any other suitable material. For PCB embodiments, different types of PCBs may be used, such as a standard FR-4 PCB, a metal core PCB, or any other type of PCB. In yet another embodiment, the support structure may be embodied as a lead frame structure. Aspects of the present disclosure are provided in the context of a support structure for an LED chip that can emit light in any number of wavelength ranges, including wavelengths within the UV and / or visible spectrum.

[0051] UV LEDs are particularly suitable for applications related to air, water and surface microbial disinfection. In other applications, UVLEDs may also be equipped with one or more luminescent materials to provide a concentrated broad emission with improved color quality in the visible spectrum. Specific embodiments of the present disclosure may be well suited for applications in which LED emission is provided in one or more of the UV-A, UV-B and UV-C wavelength ranges. Lower peak wavelengths, such as peak wavelengths in one or more of the UV-B and UV-C wavelength ranges, may have high energy levels, which may lead to the decomposition of materials commonly used in other LED packages, including silicones, polymers and / or other organic materials that are commonly used as encapsulants and / or adhesives for reflective particles and / or luminescent materials. The covering structure of the UV-based LED package may also need to provide protection from exposure to the external environment, such as providing an airtight seal, etc. As used herein, an airtight seal generally refers to an airtight and watertight seal, thereby preventing air, gas and / or liquid from passing through. In this regard, organic materials, such as silicones and epoxy resins, are not considered to be airtight seals due to their permeability. In this way, a cover structure for a UV LED can include at least one of glass, quartz and / or ceramic materials that can reduce degradation due to exposure to UV emission while also being capable of being attached or otherwise bonded to a packaging support structure to hermetically seal the LED chip underneath.

[0052] The support structure of the LED package may include one or more conductive materials that can provide electrical connections to the LED chip. The conductive material may be disposed on the base as a metal trace or a patterned metal trace, or the conductive material may form a lead frame structure that may or may not include a corresponding base. The conductive material may include any number of materials, including copper (Cu) or its alloys, nickel (Ni) or its alloys, nickel chromium (NiCr), gold (Au) or its alloys, chemical Au plating, chemical silver plating (Ag), NiAg, Al or its alloys, titanium tungsten (TiW), titanium tungsten nitride (TiWN), chemical nickel plating chemical palladium plating immersion gold (ENEPIG), chemical nickel plating immersion gold (ENIG), hot air solder leveling (HASL) and organic solderability preservative (OSP). In a particular embodiment, the conductive material may include ENEPIG or ENIG, and ENEPIG or ENIG includes an Au top layer. In other embodiments, the conductive material may include an Ag top layer. Au and Ag exhibit poor reflectivity (e.g., a reflectivity of about 20% to 40%) for UV-B and UV-C wavelength spectra. In such an embodiment, a layer with increased reflectivity with respect to UV emission, such as Al, may be disposed on or otherwise merged with the conductive material.

[0053] According to the principles disclosed herein, the arrangement of dielectric reflectors provides further increased reflectivity for LED packages. In certain embodiments, the dielectric reflectors can be configured to provide increased reflectivity for specific wavelengths (e.g., UV wavelengths) while also being composed of a material that resists degradation associated with UV exposure. As will be described in more detail later, the dielectric reflectors can include a multilayer structure that forms a distributed Bragg reflector or even a non-periodic distributed Bragg reflector. Such dielectric reflectors can be disposed on patterned metal traces and / or on portions of the package base that are located between patterned metal traces, thereby providing an increased reflective surface without electrically shorting adjacent electrical traces.

[0054] Figure 1 1 is a top view of a portion of an LED package 10 according to the principles of the present disclosure, the portion including portions 14-1 to 14-3 of a first patterned trace (collectively referred to herein as the first patterned trace 14) disposed on a base 12 and a dielectric reflector 18. As used herein, the base 12 is a form of a support structure for the LED package 10. The first patterned trace 14 can form several discontinuous portions or traces 14-1 to 14-3 on the base 12. For example, the discontinuous portions or traces 14-2 and 14-3 of the first patterned trace 14 can form a die attach pad for an LED chip, wherein one of the discontinuous portions 14-2, 14-3 forms an anode pad of the die attach pad and the other of the discontinuous portions 14-2, 14-3 forms a corresponding cathode pad of the die attach pad. In this manner, the LED chip can be mounted to the die attach pad in a flip chip manner. A through hole 16 may be provided that electrically connects the discontinuous portions 14-2, 14-3 to corresponding electrical connections on the back side or bottom surface of the base 12. In a particular embodiment, the protrusions 14-2', 14-3' of the discontinuous portions 14-2, 14-3 may extend away from the die attach pad area to form an attachment area for another component, such as an electrical overstress component (e.g., an ESD chip, a Zener diode, etc.) that may be coupled in parallel with the LED chip. As shown, portions of the base 12 between and around the discontinuous portions 14-2, 14-3 are not or are not covered by the first patterned trace 14. In a particular embodiment, the discontinuous portion 14-1 may be provided on the base 12 around the perimeter of the discontinuous portions 14-2, 14-3.

[0055] The first patterned trace 14 may include one or more layers of copper, gold, silver, ENEPIG, ENIG, etc. that exhibit reduced reflectivity to UV-B and UV-C emissions. In a particular embodiment, a dielectric reflector 18 is selectively disposed on the first patterned trace 14. Figure 1 In the embodiment, the dielectric reflector 18 is disposed on a portion of the discontinuous portion 14-1 (e.g., Figures 5A-6B ). The dielectric reflector 18 can include any material that exhibits increased reflectivity (such as at least 60% reflectivity, or at least 80% reflectivity, or at least 90% reflectivity) for a particular LED emission as compared to the first patterned trace 14. As an example, for UV-B and UV-C wavelengths, aluminum can provide at least 90% reflectivity, while the material of the first patterned trace 14 can exhibit a reflectivity of less than 40%. As will be described in more detail later, the cover structure can be mounted to the base 12 via a metallurgical bonding material. Although the dielectric reflector 18 can exhibit increased reflectivity, the metallurgical bonding material can have improved adhesion to the material of the first patterned trace 14. In this regard, the dielectric reflector 18 is selectively disposed on the first patterned trace 14 to allow the cover structure mounting area to directly access the first patterned trace 14. Figure 1 , the portion of the discontinuous portion 14-1 that is not or is not covered by the dielectric reflector 18 forms a cover structure mounting area disposed at the periphery of the surface of the base 12. Therefore, the cover structure for the LED package 10 can be mounted so that the cover structure contacts the base 12 only in the cover structure mounting area. In this way, the dielectric reflector 18 can be disposed on the portion of the first patterned trace 14 that is located between the die attach pads (e.g., 14-2, 14-3) and the cover structure mounting area. As will be described in more detail later, in other embodiments, the dielectric reflector 18 can alternatively extend across the cover structure mounting area so that all or substantially all of the base 12 except the die attach pads of the LED chip and the attachment area of ​​the electrical overstress element is covered by the dielectric reflector 18.

[0056] Figure 2 is with Figure 1 FIG. 1 is a top view of a portion of an LED package 20 that is similar to the LED package 10 and has an alternative layout for the dielectric reflector 18. As shown, the dielectric reflector 18 forms a circular shape on the discontinuous portion 14-1 of the first patterned trace 14. In this regard, the cover structure mounting area formed by the area of ​​the discontinuous portion 14-1 that is not or is not covered by the dielectric reflector 18 is also provided with a corresponding circular pattern. This arrangement can be well suited for a cover structure including a dome lens mounted on the base 12. Figure 1 Likewise, the dielectric reflector 18 may extend to the peripheral edge of the submount 12 to cover all or substantially all of the area on the submount 12 except for the die attach pads of the LED chips, and the attachment area of ​​the electrical overstress element is covered by the dielectric reflector 18 .

[0057] Figure 3is a cross-sectional view of an exemplary dielectric reflector 18 that may be provided for any previous or subsequent embodiment of the present disclosure. The dielectric reflector 18 may include a plurality of dielectric layers 18-1 to 18-9 configured to enhance light reflection from an associated LED chip. In particular embodiments, the material and / or thickness of each of the dielectric layers 18-1 to 18-9 may be arranged to provide a varying optical thickness. Optical thickness, which may also refer to optical path length, may be defined as the product of the refractive index of a material and the geometric length of the path that light travels through the layer. Thus, the optical thickness of an individual layer 18-1 to 18-9 may be altered by increasing or decreasing the actual layer thickness and / or by providing the layer with a different material type than another layer of the layers 18-1 to 18-9. In particular embodiments, the dielectric layers 18-1 to 18-9 may form layers of alternating optical thicknesses such that the dielectric reflector 18 comprises a distributed Bragg reflector. For example, each of dielectric layers 18-1, 18-3, 18-5, 18-7, and 18-9 may include a first material type, while each of dielectric layers 18-2, 18-4, 18-6, and 18-8 may include a second material type having a different refractive index than the first material type.

[0058] The dielectric reflector 18 may also form a non-periodic distributed Bragg reflector, wherein the optical thickness for each of the dielectric layers 18-1 to 18-9 varies throughout a portion of the dielectric reflector 18. In certain embodiments, each individual dielectric layer 18-1 to 18-9 may include a unique optical thickness compared to the other dielectric layers 18-1 to 18-9. For example, each of the dielectric layers 18-1, 18-3, 18-5, 18-7, and 18-9 may include a first material type, but the relative thicknesses of the dielectric layers 18-1, 18-3, 18-5, 18-7, and 18-9 may vary. In certain embodiments, the dielectric layer 18-3 in the interior of the dielectric reflector 18 is the thickest layer, while the other dielectric layers 18-1, 18-5, 18-7, and 18-9 may also have varying thicknesses relative to each other. In a similar manner, the dielectric layers 18-2, 18-4, 18-6, and 18-8 may include a second material type having a different refractive index than the first material type, and one or more of the dielectric layers 18-2, 18-4, 18-6, and 18-8 may also have a thickness that varies relative to each other. In this manner, the interface between each pair of adjacent dielectric layers 18-1 to 18-9 may provide a different total internal reflection (TIR) ​​response based on the incident angle and wavelength of the light. A dielectric layer having a larger optical thickness (e.g., 18-3) will generally promote TIR of light having a smaller incident angle than another layer having a smaller optical thickness (e.g., 18-1). In this manner, it may be advantageous to position the layer having the thickest optical thickness (e.g., 18-3) inside the dielectric reflector 18 and away from its top surface, or even at the bottom of the dielectric reflector 18, so that light having a larger incident angle can be redirected earlier, thereby avoiding potential light loss due to internal absorption. Thus, having multiple layers with different optical thicknesses allows some layers to reflect more light incident at smaller angles, while other layers reflect more light incident at larger angles, thereby providing the multiple layers with increased total reflection at all angles.

[0059] The materials of the dielectric layers 18-1 to 18-9 may include aluminum oxide (Al2O3), hafnium oxide (HfO2), silicon dioxide (SiO2), zirconium dioxide (ZrO2), and / or silicon nitride, among others. In the context of UV emission, dielectric layers 18-1 to 18-9 having higher optical thickness contrast and / or higher refractive index difference may be used to appropriately redirect such wavelengths. For example, the ability to independently adjust the optical thickness of each of the dielectric layers 18-1 to 18-9 may provide a reflectivity value of at least 97% or in the range of from 97% to 99% for UV emission in the range from 250nm to 315nm or from 200nm to 315nm. Such reflectivity values ​​exceed conventional metal reflective layers typically employed in UV LED packages. In yet another embodiment, the ability to independently adjust the optical thickness of each of the dielectric layers 18-1 to 18-9 may also provide the ability to specifically customize the emission pattern and / or wavelength range of the LED package.

[0060] Figure 4A FIG. 2 is a cross-sectional view of a structure 22 including a first patterned trace 14 and a dielectric reflector 18 according to a particular embodiment. For illustration purposes, the dielectric reflector 18 is not depicted. Figure 3 details, but it should be understood that the dielectric reflector 18 may include the above Figure 3 Any of the described layers 18-1 to 18-9. Figure 4A Any embodiment of the present disclosure from the region where the dielectric reflector 18 is formed on the first patterned trace 14 can be represented. As shown, the first patterned trace 14 can be embodied as a multi-layer structure, such as a first layer 24, a second layer 26, and a third layer 28 of the first patterned trace 14. In a particular embodiment, the first layer 24 can include a layer of Cu and / or its alloys, the second layer 26 can include one or more layers of Ni, palladium (Pd), or their alloys, and the third layer 28 can include a layer of Au. The first patterned trace 14 can include an electrolytic layer and can be collectively referred to as an ENEPIG layer. In a particular embodiment, a thin bonding layer including titanium (Ti) and / or its alloys can be disposed on the bottom side of the first layer 24 for bonding to an underlying substrate.

[0061] Figure 4B FIG. 3 is a cross-sectional view 32 of a structure 30 for an alternative arrangement of first patterned traces 14 and dielectric reflectors 18. Figure 4B In the embodiment shown in FIG. 1 , structure 30 includes a layer 31 that occupies most or even all of first patterned trace 14. In a particular embodiment, a thin adhesive layer can be provided on the bottom side of layer 31. For Cu-free embodiments, layer 31 can include an Au layer. Alternatively, layer 31 can include a Cu layer and have a thin silver layer on the top side at the interface with dielectric reflector 18.

[0062] FIG. 5A to FIG. 16 are cross-sectional views of LED packages having various configurations of dielectric reflectors 18 and first patterned traces 14 as described above. FIG. 5A to FIG. 16 As shown above for Figure 4A The first patterned trace 14 is described. However, it should be understood that FIG. 5A to FIG. 16 The first patterned trace 14 in each of the may alternatively include the above for Figure 4B In addition, FIG. 5A to FIG. 16 The dielectric reflector 18 may include the above Figure 3 Describes any structure.

[0063] Figure 5A According to the principles of the present disclosure, Figure 1 FIG. 1 is a cross-sectional view of an LED package 34 taken from a portion of the LED package 34 similar to the section line AA, and wherein the LED package 34 is assembled with at least one LED chip 36 and a cover structure 38. Depending on the embodiment and the target application, the LED chip 36 can be configured to emit a peak wavelength in any one of the visible spectrum or the UV spectrum, including a peak wavelength in the range from 200 nm to 750 nm or in the range from 200 nm to 400 nm. As shown, the LED chip 36 is mounted on a portion of the first patterned trace 14 (e.g., Figure 1 The through hole 16 can extend through the entire thickness of the base 12 to provide an electrical connection between the LED chip 36 on the top surface of the base 12 and the corresponding portion of the second patterned trace 15 disposed on the bottom surface of the base 12. The second patterned trace 15 can be configured to receive external electrical connections for the LED package 34. In addition, the second patterned trace 15 can be provided with sufficient surface area across the bottom surface of the base 12 to improve heat dissipation of the LED package 34. In particular embodiments, the second patterned trace 15 can include an arrangement similar to the first patterned trace 14, such that the first layer 24, the second layer 26, and the third layer 28 are disposed in sequence on the bottom surface of the base 12. In other embodiments, the second patterned trace 15 can include a structure different from the first patterned trace 14.

[0064] A cover structure 38 may be formed over the LED chip 36 and attached to the first patterned trace 14 at or near the perimeter of the LED package 34. Such an attachment area may be referred to as a cover structure mounting area. The cover structure 38 may include vertical sidewalls extending to the base 12 in one or more locations below the height of the LED chip 36. To this end, the cover structure 38 may form a cavity 40 or opening above the LED chip 36 and above the base 12. In a particular embodiment, the cavity 40 may be filled with air and / or nitrogen. In a particular embodiment, the cavity 40 may be under a vacuum relative to the surrounding atmosphere, depending on how the cover structure 38 is attached. In a particular embodiment, the cover structure 38 forms an airtight seal for the LED package 34. As shown, the cover structure mounting area is defined as an area where the cover structure 38 is attached to the first patterned trace 14 at or near the perimeter of the base 12. In a particular embodiment, the cover structure 38 may form a lens having a dome-shaped or hemispherical shape for directing light emission from the LED chip 36. In certain embodiments, the lens may include many different shapes depending on the desired light output shape. Suitable shapes include hemispherical, ellipsoidal, ellipsoidal bullet, cubic, flat, hexagonal, and square. In certain embodiments, suitable shapes include both curved and flat surfaces, such as a hemispherical or curved top portion with flat side surfaces. Figure 5A As shown, the ends of the curved top portion of the cover structure 38 may be aligned with corresponding ends of the cavity 40 .

[0065] While the material of the first patterned trace 14 can provide good adhesion for mounting the LED chip 36 and the cover structure 38, the material of the first patterned trace 14 can have an unsuitable reflectivity, particularly for embodiments where the LED chip 36 provides UV-B and / or UV-C light. To this end, a dielectric reflector 18 is disposed on a portion of the first patterned trace 14 located between the die attach pad of the LED chip 36 and the cover structure mounting area. By arranging the dielectric reflector 18 over the portion of the first patterned trace 14 that will be exposed within the cavity 40, increased reflectivity is provided, thereby increasing light emission from the LED package 34. While the dielectric reflector 18 can be configured for all wavelengths of light, including visible and UV, the dielectric reflector 18 can be particularly useful for UV applications where traditional insulating reflective materials, such as white solder resist, can degrade under UV emission. As shown, in a particular embodiment, at least a portion of the dielectric reflector 18 can be self-aligned with at least one edge of the first patterned trace 14.

[0066] Figure 5B is along with Figure 1 The section line BB is similar to the section of the LED package 34 taken in the area outside the LED chip 36. Figure 5A 4. As shown, a dielectric reflector 18 can be disposed along the first patterned trace 14 substantially entirely outside the LED chip 36 and within the cavity 40 to provide enhanced reflectivity. Figure 5A and Figure 5B , the dielectric reflector 18 is shown with a small gap near the cover structure 38 to provide installation tolerance for the cover structure 38. In other embodiments, the dielectric reflector 18 may extend completely from one end of the cavity 40 to the other end without any gap.

[0067] Fig. 6A is an alternative arrangement with a covering structure 38 similar to Figure 5A and Figure 5B FIG. 4 is a cross-sectional view of LED package 34 and LED package 42 . Fig. 6A The cross-sectional view provided in FIG. 4 is taken along the LED package 42 and the Figure 5A A similar partially cutaway view of the LED package 34 is provided. Figure 6B is along with Figure 1 The section line BB is similar to the section of the LED package 42 taken in the area outside the LED chip 36. Fig. 6A The LED package 42 is similar to Figure 5A and Figure 5B however, the cover structure 38 forms a flat or planar cover over the base 12, the cover having vertical sidewalls extending to a position in the base 12 below the height of the LED chip 36. In this regard, for certain applications, the LED package 42 can be provided with a lower profile.

[0068] Fig. 7A According to the principles of the present disclosure, Figure 1 Section line AA is a cross-sectional view of the LED package 44 taken similarly to a portion of the LED package 44 and wherein the dielectric reflector 18 is disposed between the cover structure 38 and the base 12 in the cover structure mounting region. Figure 7B is along with Figure 1 The cross-sectional line BB is similar to a portion of the LED package 44 cut out of Fig. 7A A cross-sectional view of an LED package 44. The LED package 44 is Figure 5A and Figure 5B34, except that the dielectric reflector 18 extends between the cover structure 38 and the base 12 in the cover structure mounting area. In this regard, the dielectric reflector 18 can cover the entire area of ​​the first patterned trace 14 that is discontinuous with the die attach pad of the LED chip 36. Such a configuration can be well suited for embodiments in which the cover structure 38 includes a material that does not require metallurgical attachment, such as glass, etc. In this regard, the cover structure 38 can be mounted to a portion of the dielectric reflector 18, and in some cases, the reflectivity in the cover structure mounting area of ​​the LED package 44 can be improved, particularly for UV applications.

[0069] Fig. 8A is with Fig. 6A and Figure 6B LED package 42 is similar to a cross-sectional view of LED package 46 and wherein dielectric reflector 18 is disposed between cover structure 38 and submount 12 in the cover structure mounting region. Fig. 8A The cross-sectional view provided in FIG. 4 is taken along the LED package 46 and the Fig. 6A A similar partially cutaway view of the LED package 42 is provided. Figure 8B is along with Figure 1 The section line BB is similar to the section of the LED package 46 taken in the area outside the LED chip 36. Fig. 8A For embodiments where the cover structure 38 forms a flat or planar cover over the base 12, the cover having vertical sidewalls extending to a position in the base 12 below the height of the LED chip 36, the LED package 46 is similar to Fig. 7A and Figure 7B LED package 44. In this regard, for certain applications, LED package 46 can be provided with a lower profile.

[0070] Fig. 9 is with Figure 5A 4 and 5. A similar cross-sectional view of an LED package 48 is shown, and in which the dielectric reflector 18 is also disposed on portions of the submount 12 that are laterally adjacent to the first patterned traces 14. In this manner, the dielectric reflector 18 can be disposed on portions of the submount 12 that do not have the first patterned traces 14 therebetween. For example, portions of the dielectric reflector 18 can be located on the submount 12 to form a die attach pad (e.g., Figure 114-2, 14-3). In this way, the dielectric reflector 18 can be positioned between the LED chip 36 and the base 12 to reflect the light propagating downward toward the covering structure 38. In order to avoid topographic differences for mounting the LED chip 36, this portion of the dielectric reflector 18 can have a thickness that is less than the thickness of the first patterned trace 14. In a specific embodiment, the dielectric reflector 18 can cover the portion of the base 12 between the other discontinuous portions of the first patterned trace 14 outside the die attach area. Fig. 9 , such areas are shown to the left and right of LED chip 36. In this way, all or substantially all of the bottom surface of cavity 40 (including the top surface of first patterned trace 14 and the top surface of submount 12 not covered by first patterned trace 14) can be covered with dielectric reflector 18 to improve brightness. Fig. 9 As further shown in FIG. 1 , by providing a dielectric reflector 18 within the cover structure mounting area and on the portion of the submount 12 not covered by the first patterned trace 14, the dielectric reflector 18 can effectively cover the entire submount 12 except for the portion of the first patterned trace 14 where the LED chip 36 and the optional electrical overstress element are mounted. In a particular embodiment, in combination with Fig. 9 The arrangement of the dielectric reflector 18 can be Fig. 9 The LED package 48 provides Fig. 6A The covering structure 38 is arranged.

[0071] Fig.10 is with Fig. 7A A cross-sectional view of an LED package 50 similar to the LED package 44 of FIG. 1 and wherein the dielectric reflector 18 is also disposed on a portion of the base 12 that is laterally adjacent to the first patterned trace 14. Fig. 9 In a similar manner, the dielectric reflector 18 can be positioned along portions of the submount 12 between discontinuous portions of the first patterned trace 14, such as below the LED chip 36 in the gaps of the die attach pads and / or along portions of the submount 12 adjacent to the LED chip 36. Furthermore, the dielectric reflector 18 can extend along portions of the first patterned trace 14 such that the dielectric reflector 18 is between the cover structure 38 and the first patterned trace 14. In this manner, the cover structure 38 can be attached to the dielectric reflector 18.

[0072] Fig.11 According to the principles of the present disclosure, Figure 1FIG. 1 is a cross-sectional view of an LED package 52 taken along a section line AA similar to that of a portion of the LED package 52, and wherein the first patterned trace 14 is not disposed in the cover structure mounting area. As shown, the first patterned trace 14 may be disposed only in the die attach pad (e.g., Figure 1 14-2, 14-3). In this regard, the dielectric reflector 18 can be disposed on an area of ​​the periphery of the base 12 that surrounds the LED chip 36 and the first patterned trace 14 and is devoid of the first patterned trace 14. The dielectric reflector 18 can even be arranged to extend to and contact the sidewalls of the first patterned trace 14 adjacent to the LED chip 36. Thus, the covering structure mounting area includes the dielectric reflector 18 instead of the first patterned trace 14. As shown, the dielectric reflector 18 can include a thickness that is the same as or greater than the first patterned trace 14 to facilitate bonding of the covering structure 38. In other embodiments, the dielectric reflector 18 can include a thickness that is less than the thickness of the first patterned trace 14. In addition, a portion of the dielectric reflector 18 can be disposed in a region where a die attach pad (e.g., Figure 1 In order to avoid the topographic difference for mounting the LED chip 36, the portion of the dielectric reflector 18 can have a thickness less than the thickness of the first patterned trace 14.

[0073] Fig.12 is with Fig.11 5 is a cross-sectional view of an LED package 52 that is similar to an LED package 54, except that the dielectric reflector 18 is not positioned within the cover structure mounting area. As shown, the first patterned trace 14 is disposed in an area of ​​the base 12 for a die attach pad and an area of ​​the base 12 for a cover structure mounting area. In this regard, the dielectric reflector 18 can cover a portion of the base 12 within the cavity 40 that is not covered by the first patterned trace 14. In a particular embodiment, the dielectric reflector 18 can even be arranged to extend to and contact the sidewalls of the first patterned trace 14 adjacent to the LED chip 36 and the cover structure mounting area.

[0074] Fig.13 is along with Figure 1FIG. 1 is a cross-sectional view of an LED package 56 taken along a section line AA similar to FIG. 1 , and wherein the LED package 56 includes a reflector structure 58 disposed between the cover structure 38 and the base 12. In a particular embodiment, the reflector structure 58 is a separate element that can be mounted or otherwise attached to one or more of the first patterned trace 14 and the base 12. As shown, the cover structure 38 can be attached to the reflector structure 58, and the reflector structure 58 and the cover structure 38 are attached to a cover structure mounting area disposed around the periphery of the LED chip 36. Fig.13 4, the cover structure mounting area of ​​the base 12 can be defined as the area where the reflector structure 58 is mounted to the first patterned trace 14. The reflector structure 58 may include an interior sidewall 58' that defines the lateral boundary of the cavity 40. In certain embodiments, the sidewall 58' can be angled relative to the base 12 to redirect laterally emitted light from the LED chip 36 through the cover structure 38 in a desired emission direction of the LED package 56. In other embodiments, the sidewall 58' can form a vertical sidewall that is substantially perpendicular to the base 12 while still redirecting lateral light emission from the LED chip 36.

[0075] The reflector structure 58 can include a material having a sufficient coefficient of thermal expansion (CTE) relative to other portions of the LED package 56. In a particular embodiment, the reflector structure 58 includes silicon and can optionally have a metal coating on the sidewalls 58', such as aluminum or an alloy thereof. In other embodiments, the entire reflector structure 58 can include a metal, such as aluminum or an alloy thereof. In still other embodiments, the reflector structure 58 can include a ceramic, such as one or more of aluminum oxide (Al2O3), zirconium dioxide (ZrO2), silicon dioxide (SiO2), and aluminum nitride (AlN). For embodiments in which the reflector structure 58 includes a ceramic material, the sidewalls 58' can be coated with a metal as described above to increase reflectivity. As shown, the dielectric reflector 18 is disposed on the exposed portions of the first patterned traces 14 within the cavity 40 to provide increased reflectivity. The dielectric reflector 18 can also be disposed on portions of the base 12 between discontinuous portions of the first patterned traces 14, such as below and / or adjacent to the LED chip 36 in the die attach pad. Although the cover structure 38 is Fig.13 Although shown as planar in FIG. 3 , the cover structure 38 may form a lens having a dome-shaped or hemispherical shape for directing light emission from the LED chip 36 .

[0076] Fig.14 is with Fig.13FIG. 5 is a cross-sectional view of an LED package 60 that is similar to the LED package 56 of FIG. 5 and wherein the dielectric reflector 18 extends over the first patterned trace 14 in a position between the reflector structure 58 and the submount 12. In this regard, the reflector structure 58 can be directly bonded to the dielectric layer 18. Extending the dielectric reflector 18 across the first patterned trace 14 and a portion of the submount 12 (as shown) can provide simplified manufacturing steps and can also provide electrical isolation between the reflector structure 58 and the dielectric reflector 18.

[0077] Fig.15 is with Fig.13 5 and 6. The LED package 56 of FIG. 5 is similar to the LED package 56 of FIG. 5 and wherein the dielectric reflector 18 extends along the sidewalls 58' of the reflector structure 58. In this manner, the dielectric reflector 18 can cover the sidewalls 58' and the floor defining the cavity 40 for increased reflectivity. In this embodiment, the dielectric reflector 18 can be formed within the LED package 62 after the reflector structure 58 is attached and before the LED chip 36 is disposed. As with other embodiments, the dielectric reflector 18 can also be disposed on portions of the base 12 between discontinuous portions of the first patterned traces 14, such as below and / or adjacent to the LED chip 36 in the die attach area.

[0078] Fig.16 is with Fig.15 The LED package 62 is similar to the cross-sectional view of the LED package 64, and wherein the dielectric reflector 18 extends along the sidewall 58' of the reflector structure 58 and between the reflector structure 58 and the first patterned trace 14. In this way, the portion of the dielectric reflector 18 on the first patterned trace 14 and the base 12 can be formed before the reflector structure 58 is attached, and the portion of the dielectric reflector 18 on the sidewall 58' can be formed after the reflector structure 58 is attached to the base 12.

[0079] It should be considered that any of the aforementioned aspects, and / or multiple individual aspects and features as described herein can be combined for additional advantages. Unless otherwise indicated herein, any of the multiple embodiments disclosed herein can be combined with one or more other disclosed embodiments.

[0080] Those skilled in the art will recognize improvements and modifications to the preferred embodiments of the present disclosure. All such improvements and modifications are considered to be within the scope of the concepts disclosed herein and the following claims.

Claims

1. A light emitting diode (LED) package, comprising: A base, comprising a first surface and a second surface opposite to the first surface; at least one LED chip, on the first surface of the base; A covering structure arranged above the at least one LED chip; a patterned trace, on the first side of the base, the cover structure attached to the patterned trace at a cover structure mounting area, the cover structure mounting area being outside of at least one die attach pad; as well as A dielectric reflector comprises a distributed Bragg reflector on a portion of the patterned trace between the at least one die attach pad and the cover structure mounting area.

2. The LED package according to claim 1, wherein: The distributed Bragg reflector is a non-periodic distributed Bragg reflector.

3. The LED package according to claim 2, wherein: The non-periodic distributed Bragg reflector comprises a plurality of dielectric layers; and Each dielectric layer of the plurality of dielectric layers comprises a unique optical thickness relative to other dielectric layers of the plurality of dielectric layers.

4. The LED package according to claim 3, wherein: The plurality of dielectric layers includes alternating dielectric layers of a first material type and a second material type.

5. The LED package according to claim 1, wherein: The dielectric reflector is further on a portion of the submount not covered by the patterned traces and the at least one LED chip.

6. The LED package according to claim 5, wherein: The dielectric reflector is further disposed between the at least one LED chip and the submount in a gap formed by the patterned trace along the at least one die attach pad.

7. The LED package according to claim 6, wherein: The at least one LED chip is configured to provide a peak wavelength within a range from 200 nm to 400 nm.

8. A light emitting diode (LED) package, comprising: A base, comprising a first surface and a second surface opposite to the first surface; at least one LED chip, on the first surface of the base; a cover structure disposed over the at least one LED chip, the cover structure mounted to the base at a cover structure mounting area spaced apart from a peripheral boundary of the at least one LED chip; a patterned trace on the first side of the submount, the patterned trace forming at least one die attach pad for the at least one LED chip; and A dielectric reflector comprises a distributed Bragg reflector on a portion of the base laterally adjacent to the patterned trace.

9. The LED package according to claim 8, wherein: The dielectric reflector is further disposed on portions of the patterned traces.

10. The LED package according to claim 8, wherein: The dielectric reflector is further arranged between the base and the cover structure at the cover structure mounting area.

11. The LED package according to claim 8, wherein: The distributed Bragg reflector is a non-periodic distributed Bragg reflector; The non-periodic distributed Bragg reflector comprises a plurality of dielectric layers; and Each dielectric layer of the plurality of dielectric layers comprises a unique optical thickness relative to other dielectric layers of the plurality of dielectric layers.

12. The LED package according to claim 11, wherein: The plurality of dielectric layers includes alternating dielectric layers of a first material type and a second material type.

13. The LED package according to claim 11, wherein: A dielectric layer having a maximum optical thickness among the plurality of dielectric layers is positioned to be spaced apart from a top surface of the non-periodic distributed Bragg reflector and to be inside the non-periodic distributed Bragg reflector.

14. The LED package according to claim 8, wherein: The at least one LED chip is configured to provide a peak wavelength within a range from 200 nm to 400 nm.

15. A light emitting diode (LED) package, comprising: A base, comprising a first surface and a second surface opposite to the first surface; at least one LED chip, on the first surface of the base; a patterned trace on said first side of said base; as well as A dielectric reflector on portions of the patterned trace and on portions of the base laterally adjacent to the patterned trace, the dielectric reflector comprising a distributed Bragg reflector.

16. The LED package according to claim 15, wherein: The distributed Bragg reflector is a non-periodic distributed Bragg reflector.

17. The LED package according to claim 16, wherein: The non-periodic distributed Bragg reflector comprises a plurality of dielectric layers; and Each dielectric layer in the plurality of dielectric layers comprises a unique optical thickness relative to other dielectric layers in the plurality of dielectric layers.

18. The LED package according to claim 17, wherein: The plurality of dielectric layers includes alternating dielectric layers of a first material type and a second material type.

19. The LED package according to claim 17, wherein: A dielectric layer having a maximum optical thickness among the plurality of dielectric layers is positioned to be spaced apart from a top surface of the non-periodic distributed Bragg reflector and to be inside the non-periodic distributed Bragg reflector.

20. The LED package according to claim 15, wherein: The patterned trace includes at least one die attach pad for the at least one LED chip; and The dielectric reflector is also disposed between the at least one LED chip and the submount in a gap formed by the patterned trace along the at least one die attach pad.

21. The LED package according to claim 15, wherein: The at least one LED chip is configured to provide a peak wavelength within a range from 200 nm to 400 nm.

22. The LED package of claim 15, further comprising a cover structure disposed over the submount to form a cavity over the at least one LED chip.

23. The LED package of claim 22, further comprising a reflector structure disposed between the cover structure and the base, wherein: Sidewalls of the reflector structure define portions of the cavity.

24. The LED package according to claim 23, wherein: The dielectric reflector is arranged on a side wall of the reflector structure.

25. The LED package according to claim 23, wherein: The dielectric reflector is disposed between the reflector structure and the base.

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