Light emitting diode package with lead frame structure for flip-chip mounting of light emitting diode chips

Abstract

Disclosed is a light emitting diode (LED) package, and more particularly, an LED package having a lead frame structure for mounting an LED chip in a flip-chip manner. The lead frame structure includes a plurality of leads arranged for flip-chip mounting of LED chips across adjacent pairs of leads. An arrangement of stress relief features and anchoring features relative to a mounting location is provided in a lead frame structure to enhance the mechanical integrity of flip chip bonding during thermal cycling. The LED package may also include a housing formed around the lead frame structure. The housing may include a recess having a recess floor arrangement for positioning the LED chips.

Description

Technical Field

[0001] The present disclosure relates to a light emitting diode (LED) package, and more particularly to an LED package having a lead frame structure for mounting an LED chip in a flip-chip manner. Background Art

[0002] Solid-state lighting devices such as light emitting diodes (LEDs) are increasingly used in both consumer and commercial applications. Advances in LED technology have resulted in 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 used in general lighting applications, often replacing incandescent and fluorescent light sources.

[0003] LEDs are solid-state devices that convert electrical energy into light, and typically include one or more active layers (or active regions) of semiconductor material arranged between oppositely doped n-type and p-type layers. When a bias is applied to the doped layers, holes and electrons are injected into the active layer or layers, where they are recombined to generate emission, such as visible or ultraviolet light emission. LED chips typically include an active region, which can be made of, for example, silicon carbide, gallium nitride, gallium phosphide, aluminum nitride, gallium arsenide-based materials, and / or of organic semiconductor materials. Photons generated by the active region are excited in all directions.

[0004] An LED package is a solid-state device that incorporates one or more LED chips into a single packaged device. LED packages have been developed that can provide mechanical support, electrical connections, and encapsulation for the LED chips. Fluorescent materials such as phosphors can also be placed in close proximity to the LED emitter to convert part of the light emission to a different wavelength. Light emission that leaves the surface of the LED emitter typically interacts with various elements or surfaces of the LED package and the fluorescent material before exiting, increasing the chance of light loss and potential non-uniformity of light emission.

[0005] Generally, it is desirable to operate LED chips and LED packages at the highest possible light emission efficiency, which can be measured by emission intensity related to input power (e.g., lumens per watt). In order to meet the demands of modern LED technology, LED packages with compact size, higher light output, and higher efficiency are increasingly being developed. However, providing high light emission efficiency in an LED package while also producing high quality light with desired emission characteristics can be challenging.

[0006] The art continues to seek improved LED and solid state lighting devices having desirable lighting characteristics that overcome challenges associated with conventional lighting devices. Summary of the invention

[0007] The present disclosure relates to light emitting diode (LED) packages, and more particularly to LED packages having a lead frame structure for mounting an LED chip in a flip chip manner. The lead frame structure includes a plurality of leads arranged for mounting an LED chip in a flip chip manner across adjacent lead pairs. An arrangement of stress relief features and anchoring features relative to a mounting position is provided in the lead frame structure to enhance the mechanical integrity of the flip chip bonding during thermal cycling. The LED package may also include a housing formed around the lead frame structure. The housing may include a recess having a recessed floor arrangement for positioning the LED chip.

[0008] In one aspect, an LED package includes: a housing forming a recess having a recess floor and one or more recess sidewalls; a lead frame structure extending through the housing, the lead frame structure including a first lead, a second lead, and a third lead; a first LED chip mounted to a mounting location of the first lead and a mounting location of the second lead in a flip-chip manner; and a second LED chip mounted to another mounting location of the second lead and a mounting location of the third lead in a flip-chip manner; wherein each of the mounting locations of the first lead, the second lead, and the third lead is surrounded on at least three edges by a stress relief feature of the lead frame structure. In some embodiments, the stress relief feature includes one or more of a notch and a groove located in at least one of the first lead, the second lead, and the third lead. In some embodiments, the stress relief feature includes a notch extending into the first lead in a first direction to define two opposing edges of the mounting location of the first lead. In some embodiments, the stress relief feature further comprises a groove in the first lead, the groove extending along the length of the first lead in a second direction, the second direction being perpendicular to the first direction, the groove defining a third side of the mounting location between the two opposing edges. In some embodiments, a fourth edge of the mounting location of the first lead defines a portion of the gap between the mounting locations of the second lead.

[0009] The LED package may also include a plurality of anchoring features located in each of the first lead, the second lead, and the third lead. In some embodiments, the plurality of anchoring features include an opening located in each of the first lead, the second lead, and the third lead, and portions of the housing are located within each of the openings. In some embodiments, the first opening located in the first lead includes an extension of the first opening that extends toward the mounting location of the first lead. In some embodiments, the stress relief feature includes a groove located in the first lead that extends along the length of the first lead, and the plurality of anchoring features form an opening in the first lead that is located within the groove. In some embodiments, the bottom edges of the first lead, the second lead, and the third lead are laterally recessed from the edge of the mounting location. In some embodiments, the second lead forms a thermal pad that includes one or more openings, and portions of the housing are located within the one or more openings.

[0010] The LED package may further include an electrical overstress element mounted on the first lead and electrically coupled to the third lead, wherein the bottom edge of one or more of the first lead and the second lead is laterally recessed from the mounting position of the electrical overstress element. The LED package may further include a ridge extending upward from the recess floor. In some embodiments, at least one of the first lead and the third lead forms the mounting position of the electrical overstress element, and the ridge extends between the electrical overstress element and the first LED chip. The LED package may further include: an electrical overstress element mounted on the first lead and electrically coupled to the third lead; and a light-changing material arranged to cover a portion of the recess floor located between the ridge and the sidewall of the recess, wherein the light-changing material is arranged to cover the electrical overstress element. In some embodiments, the sidewall of the ridge facing the first LED chip forms an angle in the range of 30 degrees to 75 degrees with the vertical direction. The LED package may further include: an electrical overstress element mounted on the first lead and electrically coupled to the third lead; and a light-changing material arranged in only a portion of the recess floor, wherein the light-changing material is arranged to cover the electrical overstress element.

[0011] In another aspect, an LED package includes: a housing, forming a recess having a first recess bottom plate and a second recess bottom plate, the second recess bottom plate being arranged at a greater depth within the recess than the first recess bottom plate; a lead frame structure extending through the housing, the lead frame structure including a first lead, a second lead, and a third lead; a first LED chip, mounted in a flip-chip manner to a mounting position of the first lead and a mounting position of the second lead, both of which are located below the first recess bottom plate; and a second LED chip, mounted in a flip-chip manner to another mounting position of the second lead and a mounting position of the third lead, both of which are located below the first recess bottom plate. The LED package may also include a ridge arranged between the first recess bottom plate and the second recess bottom plate, wherein the ridge extends upward from the first recess bottom plate and the second recess bottom plate into the recess. The LED package may also include a light-changing material arranged to cover the first recess bottom plate from the ridge to the sidewall of the recess. In some embodiments, the light-changing material forms a curved surface from the ridge to the sidewall of the recess. In some embodiments, the ridge is one of two ridges, the first LED chip and the second LED chip are arranged between the two ridges, and the light-changing material is arranged between the two ridges and the sidewalls of the recess. The LED package may also include additional light-changing material arranged between the second recess floor and the first LED chip. In some embodiments, the recess forms a third recess floor, which is arranged at a greater depth within the recess than the second recess floor, wherein the mounting locations of the first lead, the second lead, and the third lead are arranged at the third recess floor. The LED package may also include a ridge arranged between the first recess floor and the second recess floor, wherein the ridge extends upward from the first recess floor and the second recess floor into the recess, and the top surface of the first LED chip is arranged at a height equal to or less than the height of the ridge. In some embodiments, each of the mounting locations of the first lead, the second lead, and the third lead is surrounded by stress relief features of the lead frame structure on at least three edges. The LED package may also include an encapsulation located in the recess, wherein the encapsulation includes a fluorescent material.

[0012] In another aspect, any of the aforementioned aspects (alone or together) and / or the individual aspects and features described herein can be combined to achieve additional advantages. Unless otherwise indicated herein, any of the disclosed individual features and elements can be combined with one or more other disclosed features and elements.

[0013] Those skilled in the art will understand 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several aspects of the disclosure and, together with the description, serve to explain the principles of the disclosure.

[0015] Figure 1A is a front side view of a lead frame structure including stress relief features and anchoring features according to aspects of the present disclosure.

[0016] Figure 1B yes Figure 1A Rear side view of the lead frame structure.

[0017] Figure 1C is a top view of a light emitting diode (LED) package, the LED package comprising Figure 1A and Figure 1B A lead frame structure and a housing at least partially surrounding the lead frame structure.

[0018] Figure 1D yes Figure 1C The LED package is along Figure 1C A partial cross section taken along section line 1D-1D, on which an LED chip is mounted.

[0019] Figure 1E yes Figure 1C A top view of an LED package at a manufacturing step, wherein the light-changing material is arranged within the recess.

[0020] Figure 1F yes Figure 1E A top view of an LED package after providing a light changing material and mounting a plurality of LED chips.

[0021] Figure 2A is with Figure 1A A lead frame structure of FIG. 1 is a front side view of a similar lead frame structure having an alternative arrangement of stress relief features and anchoring features.

[0022] Figure 2B yes Figure 2A Rear side view of the lead frame structure.

[0023] Figure 2C is a top view of an LED package, which includes Figure 2A and Figure 2B A lead frame structure and a housing at least partially surrounding the lead frame structure.

[0024] Figure 2D yes Figure 2C A top view of an LED package after the light-changing material is disposed within a portion of the recess.

[0025] Figure 3A is with Figure 2AA lead frame structure of FIG. 1 is a front side view of a similar lead frame structure having an alternative arrangement of stress relief features and anchoring features.

[0026] Figure 3B yes Figure 3A Rear side view of the lead frame structure.

[0027] Figure 3C is a top view of an LED package, which includes Figure 3A and Figure 3B A lead frame structure and a housing at least partially surrounding the lead frame structure.

[0028] Figure 3D yes Figure 3C A top view of an LED package after the light-changing material is disposed within a portion of the recess.

[0029] Figure 4A is a top view of an LED package including a lead frame formed of leads and a housing and one or more ridges.

[0030] Figure 4B yes Figure 4A A top view of an LED package after the light altering material has been arranged along a portion of the housing between the ridge and the recessed sidewalls.

[0031] Figure 4C yes Figure 4B The LED package is along Figure 4B A cross section taken along section line 4C-4C.

[0032] Figure 4D yes Figure 4B The LED package is along Figure 4B A cross section taken along section line 4D-4D.

[0033] Figure 4E After the light-changing material and the encapsulation have been formed, Figure 4C A cross section of an LED package in perspective.

[0034] Figure 5 is a cross section of an LED package similar to FIG. 4A to FIG. 4E The LED package also includes an additional layer of light-changing material located within the recess. DETAILED DESCRIPTION

[0035] The embodiments set forth below represent the necessary information to enable those skilled in the art to practice the embodiments, and illustrate the best mode for practicing these embodiments. After reading the following description with reference to the accompanying drawings, those skilled in the art will understand the concepts of the present disclosure, and will recognize the applications of these concepts not specifically mentioned herein. It should be understood that these concepts and applications fall within the scope of the present disclosure and the appended claims.

[0036] It will be understood that, although the terms first, second, etc. may be used herein 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, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of this disclosure. As used herein, the term "and / or" includes any and all combinations of one or more associated listed items.

[0037] It will be understood that when an element such as a layer, a zone, or a substrate is referred to as being "on" or extending "on" another element, it may be directly on the other element, or directly extend to the other element, or there may also be an intervening element. In contrast, when an element is referred to as being "directly on" another element or extending "directly" to another element, there are no intervening elements. Similarly, it will be understood that when an element such as a layer, a zone, or a substrate is referred to as being "on" another element or extending "on" another element, it may be directly on the other element or extend directly on the other element, or there may also be an intervening element. In contrast, when an element is referred to as being "directly on" another element or extending "directly on" 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, it may be directly connected or coupled to the other element, or there may be an intervening element. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements.

[0038] Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe the relationship of one element, layer or region to another element, layer or region as shown in the figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the figures.

[0039] The terms used herein are 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 also intended to include the plural forms unless the context clearly indicates otherwise. It will also be understood that the terms "comprise", "comprising", "include", and / or "including" when used herein specify the presence of the described 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 groups thereof.

[0040] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those commonly understood by those of ordinary skill in the art to which the present disclosure belongs. It will also be understood that the terms used herein should be interpreted as having the same meaning as they have in the context of this specification and in the relevant field, and will not be interpreted as idealized or overly formal meanings unless explicitly defined as such herein.

[0041] Embodiments are described herein with reference to schematic illustrations of embodiments of the present disclosure. Therefore, the actual size of layers and elements may be different, and due to, for example, manufacturing technology and / or tolerances, variations from the illustrated shape are expected. For example, a region shown or described as a square or rectangle may have circular or curved features, and a region shown as a straight line may have some irregularities. Therefore, the regions shown in the figures are schematic, and their shapes are not intended to illustrate the precise shape of the region of the device, and are not intended to limit the scope of the present disclosure. In addition, for illustrative purposes, the size of a structure or region may be exaggerated relative to other structures or regions, and the size of the structure or region is therefore provided to illustrate the general structure of the subject, and the size of the structure or region may or may not be drawn to scale. Common elements between figures may be illustrated herein using common element numbers, and may not be repeatedly described subsequently.

[0042] The present disclosure relates to light emitting diode (LED) packages, and more particularly to LED packages having a lead frame structure for mounting an LED chip in a flip chip manner. The lead frame structure includes a plurality of leads arranged for mounting an LED chip in a flip chip manner across adjacent lead pairs. An arrangement of stress relief features and anchoring features relative to a mounting position is provided in the lead frame structure to enhance the mechanical integrity of the flip chip bonding during thermal cycling. The LED package may also include a housing formed around the lead frame structure. The housing may include a recess having a recessed floor arrangement for positioning the LED chip.

[0043] Before delving into the specific details of various aspects of the present disclosure, an overview of various elements that may be included in an exemplary LED package of the present disclosure is provided for context. An LED chip typically includes an active LED structure or region that 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 herein. The layers of the active LED structure can be made using known processes, wherein a suitable process is the manufacture 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 oppositely doped n-type and p-type epitaxial layers, all of which are continuously formed on a growth substrate. It should be understood that additional layers and elements may also be included in the active LED structure, including but not limited to buffer layers, nucleation layers, superlattice structures, undoped layers, cladding layers, contact layers, and current diffusion 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.

[0044] Active LED structures 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). For Group III nitrides, silicon (Si) is a common n-type dopant, and magnesium (Mg) is a common p-type dopant. Therefore, for Group III nitride-based material systems, the active layer, n-type layer, and p-type layer can include one or more layers of GaN, AlGaN, InGaN, and AlInGaN that are undoped or doped with Si or Mg. Other material systems include silicon carbide (SiC), organic semiconductor materials, and other III-V systems such as gallium phosphide (GaP), gallium arsenide (GaAs), and related compounds.

[0045] The active LED structure can be grown on a growth substrate that can include many materials, such as sapphire, SiC, aluminum nitride (AlN), and GaN. Different embodiments of the active LED structure can emit light of different wavelengths depending on the composition of the active layer and the n-type and p-type layers. In some embodiments, the active LED structure emits blue light with a peak wavelength range of approximately 430 nanometers (nm) to 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 700nm. In some 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, or one or more portions of the near infrared spectrum, and / or the infrared spectrum (e.g., 700nm to 1000nm). The UV spectrum is generally divided into three wavelength range categories, which are represented by the letters A, B, and C. By this means, UV-A light is generally defined as having a peak wavelength range of from 315 nm to 400 nm, UV-B is generally defined as having a peak wavelength range of from 280 nm to 315 nm, and UV-C is generally defined as having a peak wavelength range of from 100 nm to 280 nm. UV LEDs are of particular interest for use in applications related to the disinfection of microorganisms in air, water, surfaces, and the like. In other applications, UV LEDs may also be provided with one or more fluorescent materials to provide an LED package with aggregated emission having a broad spectrum and improved color quality for visible light applications.

[0046] The LED chip may also be covered by one or more fluorescent materials (also referred to herein as fluorophores) such as phosphors, so that at least some of the light from the LED chip is absorbed by the one or more fluorophores and converted into one or more different wavelength spectra according to the characteristic emission from the one or more fluorophores. In this regard, at least one fluorophore that receives at least a portion of the light generated by the LED source may re-emit light having a peak wavelength different from the LED source. The LED source and the one or more fluorophores may be selected so that their combined output forms light having one or more desired characteristics such as color, color point, intensity, etc. In some embodiments, the aggregate emission of the LED chip, optionally combined with one or more fluorophores, may be arranged to provide cool white light, neutral white light, or warm white light, such as in a color temperature range of 2500 Kelvin (K) to 10,000K. In some embodiments, fluorophores having cyan, green, amber, yellow, orange, and / or red peak wavelengths may be used. In some embodiments, the combination of the LED chip and one or more fluorophores (e.g., phosphors) emits a substantially white light combination. The one or more phosphors may include yellow (eg, YAG:Ce), green (eg, LuAg:Ce), and red (eg, Ca i-x-y Sr x Eu y AlSiN 3 ) emitting phosphors and combinations thereof.

[0047] The fluorescent materials described herein may be or may include one or more of a phosphor, a scintillator, a fluorescent ink, a quantum dot material, a daylight strip, and the like. The fluorescent material may be provided in any suitable manner, such as directly coated on one or more surfaces of the LED, dispersed in an encapsulation material configured to cover one or more LEDs, and / or coated on one or more optical or support elements (e.g., by powder coating, inkjet printing, etc.). In some embodiments, the fluorescent material may be down-converting or up-converting, and a combination of down-converting materials and up-converting materials may be provided. In some embodiments, a plurality of different (e.g., different in composition) fluorescent materials arranged to produce different peak wavelengths may be arranged to receive emissions from one or more LED chips.

[0048] As used herein, a layer or region may be considered "transparent" when at least 80% of the emitted radiation incident on a layer or region of a light emitting device is emitted through the layer or region. In addition, as used herein, a layer or region may be considered "reflective" or embodied as a "mirror" or "reflector" when at least 80% of the emitted radiation incident on a layer or region of an LED is reflected. In some embodiments, the emitted radiation includes visible light, such as blue and / or green LEDs with or without fluorescent 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 UVLEDs, appropriate materials may be selected to provide desired, and in some embodiments high, reflectivity and / or desired, and in some embodiments low absorptivity. In certain embodiments, a "light-transmitting" material may be configured to transmit at least 50% of the emitted radiation of a desired wavelength.

[0049] The present disclosure can be used for LED chips having various geometries, such as vertical or lateral geometries. Vertical geometry LED chips typically include anode and cathode connections on opposite sides or faces of the LED chip. Lateral geometry LED chips typically include both anode and cathode connections on the same side of the LED chip opposite to a substrate, such as a growth substrate. In some embodiments, the lateral geometry LED chip can be mounted on a substrate of an LED package so that the anode and cathode connections are located on the face of the LED chip opposite to the substrate. In this configuration, wire bonding can be used to provide electrical connections to the anode and cathode connections. In some embodiments, the lateral geometry LED chip can be embodied as a flip chip LED, which is mounted on a surface of the LED package so that the anode and cathode connections are located on a face of the active LED structure adjacent to the mounting surface. In this configuration, a lead frame structure can be incorporated into the LED package for providing 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 of the LED chip and the substrate of the LED package. Thus, light emitted from the active LED structure can pass through the substrate in a desired emission direction.In other embodiments, the active LED structure can be bonded to a carrier substrate, and the growth substrate can be removed so that light can exit the active LED structure without passing through the growth substrate.

[0050] According to aspects of the present disclosure, an LED package may include one or more elements, such as a fluorescent material, an encapsulant, a light-changing material, a lens, and electrical contacts, etc., which are provided with one or more LED chips. In some aspects, the LED package may include a support member, such as a lead frame structure, which may also be referred to as a lead frame. The light-changing material may be arranged within the LED package to reflect or otherwise redirect light from the one or more LED chips in a desired emission direction or pattern.

[0051] As used herein, light-altering materials may include many different materials, including light-reflecting 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-reflecting" refers to materials or particles that reflect, refract, scatter, or otherwise redirect light. For light-reflecting materials, light-altering materials may include fused silica, fumed silica, titanium dioxide (TiO 2 ) or at least one of metal particles suspended in an adhesive such as silicone or epoxy. In some aspects, the particles may have a refractive index configured to refract light emission in a desired direction. In some aspects, the light-reflecting particles may also be referred to as light-scattering particles. For light-absorbing materials, the light-changing material may include at least one of carbon, silicon, metal and organic particles suspended in an adhesive such as silicone or epoxy. Such organic particles may include various pigments, dyes and / or absorptive additives. Thixotropic materials may include one or more of glass fillers, fumed silica and / or fused silica. The light-reflecting material and the light-absorbing material may include nanoparticles. In some embodiments, the light-changing material may include a substantially white color to reflect and redirect light. In other embodiments, the light-changing material may include a substantially opaque or black color for absorbing light and increasing contrast. In some embodiments, the light-changing material includes both a light-reflecting material and a light-absorbing material suspended in an adhesive. As used herein, a layer or coating of one or more light-changing materials may be referred to as a light-changing coating. In some embodiments, the light-changing material or coating may not contain a fluorescent material.

[0052] In certain embodiments, aspects of the present disclosure relate to the arrangement of light-changing coatings in LED packages, and more particularly to LED packages having a lead frame structure at least partially surrounded by a body or housing. The lead frame structure can generally be formed of a metal, such as copper, a copper alloy, or other conductive metal. The lead frame structure can initially be part of a larger metal structure that is singulated during the manufacture of individual LED packages. Within the individual LED packages, isolated portions of the lead frame structure can form anode and cathode connections for the LED chips. The body or housing can be formed of an insulating material that is arranged to surround or enclose portions of the lead frame structure. The body can be formed on the lead frame structure prior to singulation so that the individual lead frame portions can be electrically isolated from each other and mechanically supported by the body within the individual LED packages. The body can form a cup or recess in which one or more LED chips can be mounted to a lead frame located at a floor of the recess. Portions of the lead frame structure can extend from the recess and through the body to extend or reach outside the body to provide external electrical connections. An encapsulant material, such as silicone or epoxy, may fill the recess to encapsulate the one or more LED chips.

[0053] For cost purposes, current high-efficiency mid-power LED packages typically employ lateral geometry LED chips in lead frame packages. The lateral geometry orientation with top-side wire bonding contacts and polymer-based substrate attachment materials provides a simple, efficient LED package structure. One way to increase the efficiency of such an LED package structure is to increase the active light emitting area by increasing the number of LED chips in the LED package.

[0054] In addition, LED chips in different orientations, such as flip-chip LEDs, can be used while maintaining a method of increasing the active light emitting area of ​​the package. Although the flip-chip orientation of the LED chip generally provides a more efficient LED architecture with higher operating lumens per watt, the LED chip must be in direct electrical contact with the lead frame structure. This presents many challenges, such as a more complex lead frame structure to directly bond the LED while maintaining the current forward voltage. In addition, due to the different thermal expansion coefficients between the lead frame structure and the die attach solder joints of the LED chip, the use of flip-chip LEDs directly attached to the lead frame structure may produce higher stresses within the LED package. In this regard, current LED packages with flip-chip LEDs on lead frame structures are generally limited to single LED chips with smaller package footprints, such as 3 millimeters (mm) × 3 mm.

[0055] According to various aspects of the present disclosure, an LED package having an increased number of flip chip LEDs on a lead frame structure is provided. In some aspects, a plurality of flip chip LEDs, such as 2 or more, or 3 or more, or 6 or more, may be provided in a single LED package having a lead frame structure. The individual leads of the lead frame structure may be arranged to receive and electrically connect the flip chip LEDs in series, in parallel, and in combinations thereof. In some embodiments, such an LED package may have a larger footprint, such as 5 mm×5 mm, while maintaining a suitable forward drive voltage. According to various aspects of the present disclosure, an LED package is disclosed, comprising a lead frame structure having stress relief features, anchoring features, LED chip alignment features including self-alignment features, and housing features for increasing brightness.

[0056] Figure 1A 1 is a front side view of a lead frame structure 10 including stress relief features 12, 14 and anchoring features 16 according to aspects of the present disclosure. The lead frame structure 10 may include three individual leads 10-1 to 10-3, and portions of each lead 10-1 to 10-3 form mounting locations 18 for an LED chip that will subsequently be mounted within a single LED package. As used herein, the mounting locations 18 may also be referred to as bonding pads of the lead frame structure 10. Figure 1A In an embodiment, the first lead 10-1 includes three mounting locations 18, and the second lead 10-2 includes three corresponding and adjacent mounting locations 18. Each pair of adjacent mounting locations 18 between the first lead 10-1 and the second lead 10-2 together form an anode connection portion and a cathode connection portion for an LED chip having a flip chip orientation. In this way, the LED chip will be mounted to the mounting locations 18 in a flip chip manner so that the anode and cathode of the LED chip are electrically coupled to corresponding mounting locations in the mounting locations 18 across the first lead 10-1 and the second lead 10-2. In a similar manner, the third lead 10-3 includes three mounting locations 18, and the second lead 10-2 includes three corresponding and adjacent mounting locations 18. Therefore, the lead frame structure 10 is configured to receive a first row of LED chips mounted in a flip chip manner between the first lead 10-1 and the second lead 10-2 and a second row of LED chips mounted in a flip chip manner between the second lead 10-2 and the third lead 10-3. In this way, the first row of LED chips installed in a flip-chip manner between the first lead 10-1 and the second lead 10-2 are electrically coupled to each other in parallel, the second row of LED chips installed in a flip-chip manner between the second lead 10-2 and the third lead 10-3 are electrically coupled to each other in parallel, and the first row of LED chips and the second row of LED chips are electrically coupled in series.

[0057] As described above, due to the different thermal expansion coefficients between the lead frame structure 10 and the die attach material of the LED chip, higher stresses may be generated using a flip chip LED directly attached to the lead frame structure 10. To alleviate such stresses, stress relief features 12, 14 are provided in several locations adjacent to the mounting locations 18. For example, the stress relief features 12 form notches or cutout portions of the lead frame structure 10 adjacent to the mounting locations 18. In some embodiments, the relative boundaries or edges 18 of the individual mounting locations 18 within the leads 10-1 to 10-3 are formed. 1 , 18 2 The leadframe structure 10 is defined by the stress relief features 12 located on either side of the mounting locations 18. In other embodiments, the stress relief features 12 are arranged to define the opposite edges 18 of each of the mounting locations 18 of the leadframe structure 10. 1 , 18 2 In some embodiments, the stress relief feature 14 can form a recessed area or groove extending longitudinally along one or more of the leads 10-1 to 10-3. In this way, the stress relief feature 14 can define additional boundaries of the mounting location 18. For example, the mounting location 18 can be formed at two opposite edges 18. 1 , 18 2 The third edge 18 of the mounting location 18 is defined by a stress relief feature 12 in the form of a notch extending into the leads 10 - 1 to 10 - 3 in the first direction. 3 The stress relief feature 14 may be defined by a groove in the lead 10-1 to 10-3 extending longitudinally in a second direction, the second direction being perpendicular to the first direction. 4 The lead wires 10 - 1 to 10 - 3 define a portion of the gap between adjacent mounting locations 18 of adjacent leads. By providing at least three edges 18 defining and substantially surrounding the mounting locations 18 1 Up to 18 3 By using the stress relief features 12, 14, structural failure modes associated with thermal stresses during operation can be mitigated in a manner sufficient to mount multiple LED chips in a flip chip manner.

[0058] like Figure 1AAs further shown in the figure, anchoring features 16 are provided around each of the leads 10-1 to 10-3. The anchoring features 16 form an opening in each of the leads 10-1 to 10-3 that allows the material of the housing to be formed therethrough. Thus, the anchoring features 16 can also provide mechanical stability to the lead frame structure 10 under thermal stress. The opening can be formed through the entire thickness of the leads 10-1 to 10-3. In some embodiments, the anchoring features 16 are provided in locations adjacent to the mounting locations 18 of each of the leads 10-1 to 10-3. Portions or extensions 16' of the anchoring features 16 can form narrower extensions of the opening extending toward the mounting locations 18, thereby increasing anchoring closer to the mounting locations 18 while maintaining the structural integrity of the leads 10-1 to 10-3. The anchoring features 16 can even be integrated with the stress relief features 14. As shown, each mounting location 18 can therefore be provided at least three edges 18 1 Up to 18 3 The LED chips are surrounded by a combination of the notched or cutout portions of stress relief features 12, the recessed areas or grooves of stress relief features 14, and anchor features 16. In this way, structural failure modes associated with thermal stresses during operation can be further mitigated in a manner sufficient to flip-chip mount multiple LED chips.

[0059] like Figure 1A As further shown, portions of leads 10-1 and 10-3 form mounting locations 20 for additional electrical components that may be subsequently mounted. For example, mounting locations 20 may provide mounting locations for electrical overstress components such as electrostatic discharge chips, Zener diodes, etc. In one arrangement, the electrical overstress component may be mounted to mounting location 20 of one of leads 10-1 and 10-3 and wire bonded to the other. In another arrangement, the electrical overstress component may be flip-chip bonded to both mounting locations 20. Certain edges 20 of mounting locations 20 may be bonded to the mounting locations 20. 2 and 20 3 The edge 20 may be defined by one or more stress relief features 12, 14 in a similar manner to the mounting location 18 for the LED chip. 4 A portion of the gap with the adjacent mounting position 20 may be formed, and the edge 20 1 The outer periphery of the leads 10 - 1 and 10 - 3 may be formed.

[0060] Figure 1B yes Figure 1A A rear side view of the lead frame structure 10. The edge 18 of the mounting location 18 1 , 18 2 and 18 4 from Figure 1BAs further shown in the figure, some bottom edges 10-1' to 10-3' of each of the leads 10-1 to 10-3 are separated from the edge 18 of the mounting location 18 by the lead 10-1 to 10-3. 1 , 18 2 and 18 4 In this way, the mounting location 18 can be formed with an increased surface area for mounting with the LED chip from the top side to reduce the penetration of moisture or other condensation into the mounting location 18. Thus, corrosion associated with such moisture ingress can be reduced. In addition, recessing the bottom edges 10-1' to 10-3' below the mounting location 18 can also provide increased surface area for bonding with a housing that is formed later. In some embodiments, some of the bottom edges 10-1', 10-3' can be removed from the edge 20 of the mounting location 20. 1 , 20 2 and 20 4 The lateral depressions are made in a similar manner.

[0061] In some embodiments, a portion of leads 10-1 and 10-3 is arranged to receive an external electrical connection, while the intermediate lead 10-2 provides a conductive path between leads 10-1 and 10-3 together with the LED chip installed later. Therefore, the intermediate lead 10-2 cannot be directly coupled to the external electrical connection. However, the bottom surface of the lead 10-2 can form a thermal pad for heat dissipation. In this way, the lead 10-2 can form a thermal pad with one or more anchor features 16 formed therethrough.

[0062] Figure 1C is a top perspective view of an LED package 22, which includes Figure 1A and Figure 1B The lead frame structure 10 and the housing 24 at least partially surrounding the lead frame structure 10 . Figure 1D yes Figure 1C The LED package 22 along Figure 1C FIG. 1 is a partial cross section taken along the section line 1D-1D of FIG. 1 , on which an LED chip 26 is mounted. For the purpose of illustration, the LED chip 26 is only Figure 1D It should be understood that the LED chip 26 can be mounted to Figure 1C Each of the mounting locations 18, and the electrical overstress element can be mounted to one of the mounting locations 20 and wire bonded to the other mounting location 20. Figure 1D In the cross-section of FIG. 1 , one of the anchoring features 16 is visible between portions of the lead 10-1, thereby allowing portions of the housing 24 to extend through the entire thickness of the lead 10-1 to enhance mechanical integrity. In addition, the edges of the leads 10-1, 10-2 from the mounting location 18 ( Figure 1DThe bottom edge 10-1', 10-2' of the 184) transverse depression in the middle allows the surface area of ​​the housing 24 to be contacted with each of the leads 10-1, 10-2 to be increased. In addition, an increased number of housings 24 can be located between portions of the leads 10-1, 10-2 to enhance mechanical integrity.

[0063] like Figure 1C and Figure 1D As shown, the mounting location 18 for the LED chip and the mounting location 20 for the electrical overstress chip are accessible through the housing 24. In some embodiments, the housing 24 forms a recess 24 R , the mounting positions 18, 20 can be accessed through the recess. R One or more recesses of the housing 24 may be formed within the bottom plate 24. F1 to 24 F3 . Recessed bottom plate 24 F1 The side wall 24 of the housing 24 may be defined S Arrival at recess 24 R In some embodiments, the concave bottom plate 24 F1 The LED package 22 may be defined as a single bottom plate. R The bottom portion may be formed of a plurality of separate portions and / or arranged in the recess 24. R The different depths of the recessed bottom plate 24 F1 to 24 F3 .

[0064] In some aspects, a retaining structure in the form of a ridge 28 may be disposed within the recess 24. R within to define the recess floor 24 F1 and 24 F2 The ridge 28 may be located at the bottom of the recess 24. F1 and 24 F2 The ridges 28 may extend upwardly from the housing 24 at one or more of the housings 24. The ridges 28 may include the same material as the housing 24 such that the ridges 28 are extensions of the housing 24. In this regard, the ridges 28 may be formed simultaneously with the housing 24, such as during a molding process of the housing 24 around the leads 10-1 to 10-3. In other embodiments, the ridges 28 may include a different material than the housing 24 such that the ridges 28 are formed after the housing 24 is provided around the leads 10-1 to 10-3. The ridges 28 may be formed around one or more sides of the array of mounting locations 18. For example, in Figure 1C , the ridges 28 are arranged around three sides of the array of mounting locations 18 and are aligned with the recess sidewalls 24. S Together, the entire array of mounting locations forms a raised border that defines the entire light emitting surface of the LED package 22. In this way, the recessed floor 24F1 may be arranged with the recess 24 R The other parts of the light-emitting surface may be made of different materials, including, for example, light-changing materials that will be described in more detail later. As shown, a ridge 28 may extend between mounting locations 18 and 20 to separate the electrical overstress element from the light-emitting surface.

[0065] In some embodiments, the recessed bottom plate 24 F2 can be confined within the boundaries of the ridge 28, such as Figure 1D In addition, the recessed bottom plate 24 F3 The mounting locations 18 of the leads 10-1 to 10-3 may be arranged along a plane exposed by the housing 24. In some embodiments, the mounting locations 18 may be aligned with the recessed bottom plate 24. F3 Coplanar. Figure 1D As shown, the recessed bottom plate 24 F1 can be arranged in the recess 24 R At the first depth, the recess bottom plate 24 F2 can be arranged in the recess 24 R The second depth is greater than the first depth, and the recess bottom plate 24 F3 can be arranged in the recess 24 R In this way, the recess 24 R The bottom of the recess forms a recess depth, which increases as the distance from the recess side wall 24 S In some embodiments, such an arrangement can advantageously provide the LED package 22 with a top surface of the LED chip 26 located at a desired height, such as at a height equal to or less than the height of the ridge 28. In such an arrangement, the profile of the ridge 28 can be used to define the light emitting surface of the LED package 22 and / or provide a narrower emission for the LED package 22. In other embodiments, the top surface of the LED chip 26 can be provided at a height exceeding the height of the ridge 28 to provide a wider emission from the LED package 22.

[0066] As shown in the figure, the recessed bottom plate 24 F3 forming recess 24 R The deepest part of the LED chip 26 is where the LED chip 26 is mounted to the leads 10-1, 10-2. In some embodiments, the bonding pads 30, 31 for the LED chip 26 may extend beyond the recessed bottom plate 24. F2 The defined horizontal plane is removed, thereby transferring the LED chip 26 to a lower position in the housing 24. Figure 1D In the embodiment, the LED chip 26 is arranged to be laterally suspended from the concave bottom plate 24. F2 , and the bonding pads 30 and 31 extend to the bottom plate 24 of the recess F3.exist Figure 1D In some embodiments, one of the bonding pads 30 or 31 can be embodied as an anode bonding pad of the LED chip 26, while the other of the bonding pads 30 or 31 can be embodied as a cathode bonding pad of the LED chip 26. In some embodiments, the housing 24 can exhibit increased reflectivity compared to the leads 10-1, 10-2. By providing a lateral suspension of the LED chip 26, increased brightness can be provided to the LED package 22 because an increased amount of the housing 24 is positioned below the LED chip 26.

[0067] In some embodiments, the sidewall 28 of the ridge 28 facing the LED chip 26 S can be angled to further control the target emission pattern. For example, sidewall 28 S The angle to the vertical may be in the range of 30° to 90° depending on the desired light shaping. Figure 1C As shown, the side wall 28 S It may have a slope defined by an angle in the range of 65° to 90° or 75° to 90° from the vertical direction to narrow the emission from the LED package 22 .

[0068] Figure 1E yes Figure 1C A top view of an LED package 22 at a manufacturing step, wherein the light-changing material 32 is arranged in the recess 24 R As previously described, the light-changing material 32 may include a light-reflecting material that reflects or redirects light, a light-absorbing material that absorbs light, a material that acts as a thixotropic agent, and combinations thereof. For light-reflecting applications, the light-changing material 32 may have a generally white color. For light-absorbing applications, the light-changing material 32 may have a generally dark or black color. In yet other applications where the light-changing material 32 includes both a light-reflecting material and a light-absorbing material, the light-changing material 32 may have a generally white color with a certain amount of dark particles mixed in. In addition to other application techniques, the light-changing material 32 may be applied via a dispensing tool 34. In some embodiments, the light-changing material 32 may be dispensed between the ridges 28 and the sidewalls 24 of the recesses. S 2 and 3. The ridge 28 is disposed between the ridge 28 and the recessed sidewall 24 so that the ridge 28 forms a barrier that holds and defines the boundaries of the light-altering material 32 during dispensing. The electrical overstress element 36 is shown mounted to the mounting location 20 of the lead 10-3 and is electrically coupled to the mounting location 20 of the lead 10-1 via the wire bond 38. As shown, the electrical overstress element 36 is arranged between the ridge 28 and the recessed sidewall 24. S In this way, the light altering material 32 can be dispensed to cover the electrical overstress element 36 and the wire bond 38, thereby placing such elements outside the light path of the LED package 22.

[0069] Figure 1F yes Figure 1E FIG. 2 is a top view of an LED package 22 after providing a light-changing material 32 and mounting a plurality of LED chips 26-1 to 26-6. As shown in the figure, the light-changing material 32 is arranged to completely cover the electrical overstress element 36 and the wire bonding portion 38 (at Figure 1E In this way, the light emitting surface of the LED package 22 can be formed by the border or ridge 28 of the light-changing material 32 and the recess sidewall 24. S At least one of is defined such that the boundary surrounds the periphery of the array formed by the LED chips 26 - 1 to 26 - 6 .

[0070] Figure 2A is with Figure 1A A front side view of a lead frame structure 40 similar to the lead frame structure 10 of FIG. 1, having an alternative arrangement of the stress relief features 12, 14 and the anchoring features 16. The lead frame structure 40 includes a first lead 40-1, a second lead 40-2, and a third lead 40-3, which are arranged in a manner similar to that described above for the lead frame structure 10. Figure 1A The lead frame structure 10 receives the LED chip in a similar manner as described above. Figure 2A In the embodiment, the second lead 40-2 does not include an anchor feature 16 or a stress relief feature 14 forming a recessed area or groove therethrough. Instead, the front side of the second lead 40-2 is generally planar and includes opposing edges 18 defining a mounting location 18. 1 and 18 2 Strain relief features 12. Edge 18 3 A portion of may be defined by the anchoring feature 16, and in particular by the extension 16' as previously described. Figure 1A Strain relief features 14 are provided along leads 40 - 1 and 40 - 3 in a similar manner.

[0071] Figure 2B yes Figure 2A 4. A rear side view of the lead frame structure 40. As shown, some bottom edges 40-1' to 40-3' of each of the leads 40-1 to 40-3 are as shown for Figure 1B In a similar manner as described above, the edge 18 of the mounting position 18 is 1 , 18 2 and 18 4 In addition, some bottom edges 40-1', 40-3' of the leads 40-1 and 40-3 may be extended from the edge 20 of the mounting location 20 in a similar manner. 1 , 20 2 and 20 4 Lateral depression.

[0072] Figure 2Cis a top perspective view of an LED package 42, which includes Figure 2A and Figure 2B The lead frame structure 40 and the housing 24 at least partially surrounding the lead frame structure 40. In the LED package 42, the Figure 1C The first recess bottom plate 24 has a ridge 28, and the housing 24 may include a light reflective material, a light absorbing material, or a combination thereof. F1 From the side wall 24 of the recess S The second recess bottom plate 24 is arranged to surround the periphery of the array of LED chips 26-1 to 26-6. F2 is arranged in the recess 24 R The LED chips 26-1 to 26-6 are mounted to the leads 40-1 to 40-3 at the second concave bottom plate 24. F2 As shown in the figure, the mounting location 20, the electrical overstress element 36 and the wire bonding portion 38 can be arranged in the recess 24 R Inside and outside the array of LED chips 26-1 to 26-6.

[0073] Figure 2D yes Figure 2C The LED package 42 is arranged in the recess 24 in the light changing material 32 R As shown, the light-changing material 32 is arranged to cover only the mounting location 20, the electrical overstress element 36, and the recess 24. R The wire bonds 38 within the PCB are reduced, thereby reducing absorption associated with these elements while also using a reduced amount of light altering material 32.

[0074] Figure 3A is with Figure 2A A front side view of a lead frame structure 44 similar to the lead frame structure 40 having an alternative arrangement of the stress relief features 14 and the anchoring features 16. As shown, the lead frame structure 44 does not include Figure 2A The stress relief feature 12 of the lead 44-1 to 44-3 provides a more linear gap between adjacent mounting locations 18 of adjacent leads. In this regard, an increased surface area for mounting the LED chip can be provided. Figure 1A and Figure 2A Strain relief features 14 are provided along leads 44 - 1 and 44 - 3 in a similar manner.

[0075] Figure 3B yes Figure 3A4 is a rear side view of the lead frame structure 44. As shown, certain bottom edges 44-1' to 44-3' of each of the leads 44-1 to 44-3 are laterally recessed from the edge 18' of the mounting location 18 in a similar manner as described above, only with a more linear shape. In this way, the leads 44-1 to 44-3 can be provided with increased material in the area below the LED chip, thereby providing increased heat dissipation during operation. In addition, certain bottom edges 44-1', 44-3' of the leads 44-1, 44-3 can be laterally recessed from the edge 20' of the mounting location 20 in a similar manner as described above.

[0076] Figure 3C is a top perspective view of an LED package 46, which includes Figure 3A and Figure 3B The lead frame structure 44 and the housing 24 at least partially surrounding the lead frame structure 44. The LED package 46 is similar to Figure 2C The LED package 42 may include a mounting location 20, an electrical overstress element 36, and a wire bonding portion 38 that may be arranged in the recess 24. R Inside and along the second recess bottom plate 24 F2 In this manner, the electrical overstress element 36 can be mounted along the same plane of the LED package 46 as the LED chips 26 - 1 to 26 - 6 .

[0077] Figure 3D yes Figure 3C The LED package 46 in the light-changing material 32 is arranged in the recess 24 R As shown, the light-changing material 32 is arranged to cover only the mounting location 20, the electrical overstress element 36 and the recess 24. R The wire bonding portion 38 is formed inside the second recessed bottom plate 24. F2 In this way, the position of the light-changing material 32 can be similar to Figure 2D The LED package 42 , except that the light altering material 32 may be provided at a lower height within the LED package 46 .

[0078] Figure 4A 4 is a top view of an LED package 48, which includes a lead frame formed by leads 50-1 to 50-3 and the LED package 48 shown in FIG. Figure 1C The lead frame formed by the leads 50-1 to 50-3 may be connected to the housing 24 and one or more ridges 28. FIG. 3A to FIG. 3D The lead frame structure 44 is the same as that of the lead frame 44, except that the lead frame 44 for FIG. 3A to FIG. 3DThe mounting position 20 of the electrical overstress element 36. In this regard, the LED package 48 may not include the electrical overstress element 36 as previously described, but it may be added in some embodiments. As shown, the ridge 28 can be placed on opposite sides of the array of LED chips 26-1 to 26-6. In this way, the ridge 28 can connect the opposite recessed side walls 24 of the housing 24. S , thereby defining a light emitting area therebetween. Figure 4B The light-changing material 32 of the LED package 48 has been positioned along the ridge 28 and the recessed sidewall 24 of the housing 24. S The top view after the arrangement of the part between the recessed bottom plate 24 F1 , while making the concave bottom plate 24 F2 Not covered by the light-changing material 32 .

[0079] Figure 4C yes Figure 4B The LED package 48 along Figure 4B The cross section is taken along the section line 4C-4C in FIG. For the purpose of illustration, the light-changing material 32 is omitted. The mounting locations 18 of the leads 50-1 to 50-3 may be arranged in the recessed bottom plate 24. F2 or even coplanar therewith, thereby allowing the LED chips 26 - 1 and 26 - 2 to be mounted on the recessed bottom plate 24 F1 below. Recessed bottom plate 24 F1 and recessed bottom plate 24 F2 The difference between the depths can be customized according to the specific application to R The top surfaces of the LED chips 26-1, 26-2 are provided at a desired height within the Figure 4C In the example provided, the top surfaces of the LED chips 26-1, 26-2 can be arranged at a height greater than the height of the ridge 28 to provide a wider emission for the LED package 48. In other embodiments and depending on the target light emission pattern of the LED package 48, the top surfaces of the LED chips 26-1, 26-2 can be arranged at a height similar to Figure 1D In some embodiments, the sidewall 28 of the ridge 28 facing the LED chips 26-1, 26-2 is arranged at a height equal to or lower than the height of the ridge 28. S can be angled to further control the target emission pattern. For example, sidewall 28 S The angle to the vertical may be in the range of 30° to 90° depending on the desired light shaping. Figure 4C As shown, the side wall 28 S There may be a greater degree of slope defined by an angle in the range of 30° to 75° or 45° to 75° to provide a wider emission from the LED package 48 .

[0080] Figure 4D yes Figure 4B The LED package 48 along Figure 4B 4D-4D of FIG. 4. As shown, the LED chips 26-1, 26-3, and 26-5 are all mounted to the same lead 50-1. In some embodiments, the LED chips 26-1, 26-3, and 26-5 can have multiple bonding pads 30, which can be configured as anode bonding pads or can alternatively be configured as cathode bonding pads. Although the LED chips 26-1, 26-3, and 26-5 are shown as having multiple bonding pads 30, it should be understood that each LED chip can include only a single bonding pad 30 bonded to the lead 50-1. Figure 4D As shown in the cross section, Figure 4A The ridge 28 is not visible, thereby allowing the recessed side wall 24 to S Extends all the way to the recessed bottom plate 24 F2 .

[0081] Figure 4E After the light-changing material 32 and the encapsulation body 52 have been formed, Figure 4C A cross-section of an LED package 48 is shown in FIG. 4. As shown, the light-changing material 32 may be provided in the recessed bottom plate 24. F1 On the ridge 28 and the side wall 24 of the recess S In some embodiments, the light-changing material 32 may initially be configured with a viscosity that promotes sufficient surface tension with the housing 24 so that the light-changing material 32 may be formed with a generally curved surface facing the LED chips 26-1, 26-2. The curved surface may extend from the ridge 28 to the recess sidewall 24. S After dispensing, the light-altering material 32 can be cured in place. By forming the light-altering material 32 with such a curved surface, enhanced light shaping can be provided. The encapsulant 52 can include a material such as silicone or resin that is generally optically transparent or optically transmissive to the light generated within the LED package 48. In some embodiments, fluorescent materials 54, 56 can be provided within the encapsulant 52. In some embodiments, the encapsulant 52 having the fluorescent materials 54, 56 can be dispensed in the recess 24. R and the fluorescent materials 54, 56 may be allowed to move toward the recess 24 before the encapsulation 52 is cured. R Thus, the fluorescent material 54 can be embodied as fluorescent particles in a denser area, and the fluorescent material 56 can be embodied as fluorescent particles in a less dense area within the encapsulant 52. The encapsulant 52 and fluorescent materials 54, 56 described above for the LED package 48 can be provided in the Figure 1C to Figure 1F , Figure 2C to Figure 2D as well as FIG. 3C to FIG. 3DIn any of the LED packages described.

[0082] Figure 5 is a cross-section of an LED package 58, which is similar to FIG. 4A to FIG. 4E The LED package 48 further includes a R In some embodiments, the additional layer of light-changing material 60 can be formed as a thin layer between the LED chips 26-1, 26-2 and the housing 24 to provide enhanced light reflection for the light emitted downward. Figure 5 In the embodiment, after the LED chips 26-1 and 26-2 are mounted, the light-changing material 60 is arranged to fill the concave bottom plate 24. F2 In this regard, the light-changing material 60 may cover portions of the leads 50-1 to 50-3 that are outside the bonding pads 30, 31. Additionally, the light-changing material 60 may cover portions of the housing 24 that are between the bonding pads 30, 31 of each LED chip 26-1, 26-2. In other embodiments, the light-changing material 32 may be omitted. Although the light-changing material 60 is described in the context of the LED package 58, the light-changing material 60 may be provided in the above description for the LED package 58. Figure 1C to Figure 1F , Figure 2C to Figure 2D as well as FIG. 3C to FIG. 3D In any of the LED packages described.

[0083] It is contemplated that any of the aforementioned aspects and / or the individual aspects and features described herein may be combined to achieve additional advantages. Any of the various embodiments disclosed herein may be combined with one or more other disclosed embodiments, unless otherwise indicated herein.

[0084] 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 housing forming a recess having a recess floor and one or more recess side walls; a lead frame structure extending through the housing, the lead frame structure comprising a first lead, a second lead, and a third lead; A first LED chip is mounted to the mounting position of the first lead and the mounting position of the second lead in a flip chip manner; as well as A second LED chip is mounted to another mounting position of the second lead and a mounting position of the third lead in a flip chip manner; Wherein each of the mounting locations of the first lead, the second lead and the third lead is surrounded on at least three edges by stress relief features of the lead frame structure.

2. The LED package according to claim 1, wherein: The stress relief feature includes one or more of a notch and a groove in at least one of the first lead, the second lead, and the third lead.

3. The LED package according to claim 1, wherein: The stress relief feature includes a notch extending into the first lead in a first direction to define two opposing edges of the mounting location of the first lead.

4. The LED package according to claim 3, wherein: The stress relief feature also includes a groove in the first lead, the groove extending along the length of the first lead in a second direction, the second direction being perpendicular to the first direction, the groove defining a third side of the mounting location between the two opposing edges.

5. The LED package according to claim 4, wherein: A fourth edge of the mounting locations of the first lead defines a portion of a gap between the mounting locations of the second lead.

6. The LED package of claim 1, further comprising a plurality of anchor features in each of the first lead, the second lead, and the third lead.

7. The LED package according to claim 6, wherein: The plurality of anchoring features include an opening in each of the first lead, the second lead, and the third lead, and portions of the housing are positioned within each of the openings.

8. The LED package according to claim 7, wherein: The first opening in the first lead includes an extension of the first opening, the extension extending toward the mounting position of the first lead.

9. The LED package according to claim 6, wherein: The stress relief feature includes a groove in the first lead extending along a length of the first lead, and the plurality of anchor features form openings in the first lead within the groove.

10. The LED package according to claim 1, wherein: Bottom edges of the first lead, the second lead, and the third lead are laterally recessed from an edge of the mounting location.

11. The LED package according to claim 1, wherein: The second lead forms a thermal pad including one or more openings, and portions of the housing are located within the one or more openings.

12. The LED package of claim 1, further comprising an electrical overstress element mounted on the first lead and electrically coupled to the third lead, wherein: A bottom edge of one or more of the first lead and the second lead is laterally recessed from a mounting location of the electrical overstress element.

13. The LED package of claim 1, further comprising a ridge extending upward from the recess floor.

14. The LED package according to claim 13, wherein: At least one of the first lead and the third lead forms a mounting location for an electrical overstress element, and the ridge extends between the electrical overstress element and the first LED chip.

15. The LED package according to claim 14, further comprising: an electrical overstress element mounted on the first lead and electrically coupled to the third lead; as well as A light-altering material is arranged to cover a portion of the recess floor between the ridge and the sidewalls of the recess, wherein the light-altering material is arranged to cover the electrical overstress element.

16. The LED package according to claim 13, wherein: A side wall of the ridge facing the first LED chip forms an angle in a range of 30 to 75 degrees with a vertical direction.

17. The LED package according to claim 1, further comprising: an electrical overstress element mounted on the first lead and electrically coupled to the third lead; as well as A light-altering material is arranged within only a portion of the recess floor, wherein the light-altering material is arranged to cover the electrical overstress element.

18. A light emitting diode (LED) package, comprising: a housing forming a recess having a first recess floor and a second recess floor, the second recess floor being disposed within the recess at a greater depth than the first recess floor; a lead frame structure extending through the housing, the lead frame structure comprising a first lead, a second lead, and a third lead; A first LED chip is mounted to a mounting position of the first lead and a mounting position of the second lead in a flip chip manner, wherein the mounting positions are both located below the bottom plate of the first recess; as well as The second LED chip is mounted to another mounting position of the second lead and the mounting position of the third lead in a flip chip manner, and the mounting positions are both located below the bottom plate of the first recess.

19. The LED package of claim 18, further comprising a ridge disposed between the first recess bottom plate and the second recess bottom plate, wherein: The ridge extends upwardly into the recess from the first recess floor and the second recess floor.

20. The LED package of claim 19, further comprising a light altering material arranged to cover the first recess floor from the ridge to the sidewalls of the recess.

21. The LED package according to claim 20, wherein: The light altering material forms a curved surface from the ridge to the sidewall of the recess.

22. The LED package according to claim 20, wherein: The ridge is one of two ridges, the first LED chip and the second LED chip are arranged between the two ridges, and the light changing material is arranged between the two ridges and the sidewalls of the recess.

23. The LED package of claim 20, further comprising an additional light altering material disposed between the second recess floor and the first LED chip.

24. The LED package according to claim 18, wherein: The recess forms a third recess bottom plate, which is arranged at a greater depth in the recess than the second recess bottom plate, wherein the mounting positions of the first lead, the second lead and the third lead are arranged at the third recess bottom plate.

25. The LED package of claim 24, further comprising a ridge disposed between the first recess bottom plate and the second recess bottom plate, wherein The ridge extends upward from the first recess bottom plate and the second recess bottom plate into the recess, and the top surface of the first LED chip is arranged at a height equal to or less than a height of the ridge.

26. The LED package according to claim 18, wherein: Each of the mounting locations of the first lead, the second lead, and the third lead is surrounded on at least three edges by a stress relief feature of the leadframe structure.

27. The LED package according to claim 18, further comprising an encapsulation body located in the recess, wherein: The encapsulation body includes a fluorescent material.

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