Light Emitting Height Arrangement in Light Emitting Diode Packages and Related Devices and Methods - Patent application

Abstract

Disclosed are light emitting diode (LED) packages, and more particularly, luminous height arrangements in LED packages, and related devices and methods. Disclosed are arrangements of LED packages, LED chips, and related devices that include various combinations of LED chip types, luminous materials, and / or cover structures that are arranged together while also providing substantially uniform luminous heights of corresponding luminous surfaces. LED chips may be configured with different heights or thicknesses that compensate for variations in luminous materials and / or cover structures utilized to provide different luminous colors. Corresponding LED packages and / or LED chips having different luminous colors may be assembled near one another while improving uniformity of luminous height.

Description

[Technical field]

[0001]

[0001] The present disclosure relates to light-emitting diode (LED) packages, and more particularly to emission height arrangements in LED packages, and related devices and methods. [Background technology]

[0002]

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

[0003]

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

[0004]

[0004] A lumiphoric material, such as a phosphor, may be placed in the light emission path of the LED emitter to convert a portion of the light to a different wavelength. LED packages have been developed that can provide mechanical support, electrical connection, and encapsulation for the LED emitter. The light emitted from the surface of the LED emitter typically interacts with various elements or surfaces and luminescent materials of the LED package before being emitted, increasing the possibility of light loss and potential non-uniformity of the light emission. Therefore, it may be a challenge to generate high quality light with desired light emission characteristics while providing high light emission efficiency in the LED package.

[0005]

[0005] The art continues to seek improved LED and solid state lighting devices with desirable lighting characteristics that can overcome the challenges associated with conventional lighting devices. Summary of the Invention [Means for solving the problem]

[0006] Aspects disclosed herein relate to light emitting diode (LED) packages, and more particularly, to luminous height arrangements in LED packages, and related devices and methods. Disclosed are arrangements of LED packages, LED chips, and related devices that include various combinations of LED chip types, luminous materials, and / or cover structures arranged together while also providing a substantially uniform luminous height for the corresponding luminous surfaces. The LED chips may be configured with different heights or thicknesses that compensate for variations in the luminous materials and / or cover structures utilized to provide different luminous colors. In this manner, LED packages and / or LED chips having different luminous colors may be assembled close to one another while improving the uniformity of the luminous height.

[0007] In one aspect, a method comprises providing a first LED chip and a first luminescent material layer defining a first color point, providing a second LED chip defining a second color point different from the first color point, and reducing a thickness of at least one of the first LED chip and the second LED chip such that a first emission height formed by the first LED chip and the first luminescent material layer is within 100 microns (μm) of a second emission height of the second LED chip. In a particular embodiment, the first emission height is defined as the vertical distance from a mounting surface of the first LED package to a topmost emission surface of the first LED package, and the second emission height is defined as the vertical distance from the mounting surface of the second LED chip to the topmost emission surface of the second LED chip. In certain embodiments, the top light-emitting surface of the first LED chip is defined at a top surface of the first light-emitting material layer, and the top light-emitting surface of the second LED chip is defined at a top surface of the second LED chip. In certain embodiments, the thickness of the first LED chip is reduced by an amount corresponding to the thickness of the first light-emitting material layer. In certain embodiments, reducing the thickness of at least one of the first LED chip and the second LED chip comprises reducing a thickness of a substrate of at least one of the first LED chip and the second LED chip. In certain embodiments, the first light-emitting height is within 60 μm of the second light-emitting height. In certain embodiments, the first light-emitting height is within 30 μm of the second light-emitting height.

[0008] In another aspect, a method comprises providing a first LED chip and a first luminescent material layer defining a first color point, providing a second LED chip and a second luminescent material layer defining a second color point different from the first color point, and reducing a thickness of at least one of the first LED chip and the second LED chip such that a first luminescent height formed by the first LED chip and the first luminescent material layer is within 100 microns (μm) of a second luminescent height formed by the second LED chip and the second luminescent material layer. In a particular embodiment, the first luminescent height is defined as the vertical distance from a mounting surface of the first LED chip to a top luminescent surface of the first LED chip, and the second luminescent height is defined as the vertical distance from a mounting surface of the second LED chip to a top luminescent surface of the second LED chip. In certain embodiments, a top light emitting surface of the first LED chip is defined at a top surface of the first light emitting material layer, and a top light emitting surface of the second LED chip is defined at a top surface of the second light emitting material layer. In certain embodiments, reducing the thickness of at least one of the first LED chip and the second LED chip comprises reducing a thickness of a substrate of at least one of the first LED chip and the second LED chip. In certain embodiments, the first light emitting height is within 60 μm of the second light emitting height. In certain embodiments, the first light emitting height is within 30 μm of the second light emitting height.

[0009]

[0009] In another aspect, a light emitting device includes a first LED package and a second LED package, the first LED package including a first submount, a first LED chip on the first submount, and a first light emitting material layer on the first LED chip, the first LED chip and the first light emitting material layer defining a first color point, the first light emitting height being defined as the vertical distance from a mounting surface of the first LED package to a top light emitting surface of the first LED package, the second LED package including a second submount and a second LED chip on the second submount, the second LED chip at least partially defining a second color point different from the first color point, the second light emitting height being defined as the vertical distance from the mounting surface of the second LED package to a top light emitting surface of the second LED package, and the first light emitting height is within 100 microns (μm) of the second light emitting height. In certain embodiments, the first emitting height is within 60 μm of the second emitting height. In certain embodiments, the first emitting height is within 30 μm of the second emitting height. In certain embodiments, the top emitting surface of the first LED package is defined at a top surface of the first emitting material layer, and the top emitting surface of the second LED package is defined at a top surface of the second LED chip. The light emitting device may further comprise a second emitting material layer on the second LED chip, the second LED chip and the second emitting material layer defining a second color point, the top emitting surface of the first LED package is defined at a top surface of the first emitting material layer, and the top emitting surface of the second LED package is defined at a top surface of the second emitting material layer. In certain embodiments, the first emitting material layer is provided as a coating on the first LED chip. In certain embodiments, the first luminescent material layer is disposed on or in a chip cover attached to the first LED chip.

[0010] In another aspect, an LED package includes a submount, a first LED chip on the submount, a first luminescent material layer on the first LED chip, the first LED chip and the first luminescent material layer defining a first color point, the first luminescent height being defined as the vertical distance from a mounting surface of the first LED chip to a top luminescent surface of the first LED chip, and a second LED chip on the submount, the second LED chip at least partially defining a second color point different from the first color point, the second luminescent height being defined as the vertical distance from a mounting surface of the second LED chip to a top luminescent surface of the second LED chip, the first luminescent height being within 100 μm of the second luminescent height. In a particular embodiment, the first luminescent height is within 60 μm of the second luminescent height. In a particular embodiment, the first luminescent height is within 30 μm of the second luminescent height. In certain embodiments, the top light-emitting surface of the first LED chip is defined at the top surface of the first light-emitting material layer, and the top light-emitting surface of the second LED chip is defined at the top surface of the second LED chip. The LED package may further comprise a second light-emitting material layer on the second LED chip, the second LED chip and the second light-emitting material layer defining a second color point, the top light-emitting surface of the first LED chip is defined at the top surface of the first light-emitting material layer, and the top light-emitting surface of the second LED chip is defined at the top surface of the second light-emitting material layer. In certain embodiments, the first light-emitting material is provided as a coating on the first LED chip. In certain embodiments, the first light-emitting material layer is disposed on or within a chip cover attached to the first LED chip.

[0011] In another aspect, any of the above aspects may be taken individually or together, and / or in combination with various individual aspects and features described herein to provide additional advantages. Any of the various features and elements disclosed herein may be combined with one or more of the other disclosed features and elements, unless otherwise indicated herein.

[0012]

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

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

[0013] [Figure 1]

[0014] 1 is a top view of a light emitting diode (LED) package including an LED chip mounted to a submount in accordance with the principles of the present disclosure. [Diagram 2]

[0015] 2 is a cross-sectional view of the LED package along section line AA of FIG. 1 of the LED chip including a layer of luminescent material disposed thereon. [Diagram 3]

[0016] 3 is a cross-sectional view of another arrangement of LED packages taken along section line AA of FIG. 1, which provides a different light emission color than the LED package of FIG. 2. [Figure 4]

[0017] 4 is a cross-sectional view of another arrangement of LED packages along section line AA of FIG. 1 that provides a different light emission color than the LED packages of FIG. 2 and FIG. 3. [Diagram 5]

[0018] 5 is a cross-sectional view of a light emitting device including each of the LED packages of FIGS. 2 to 4. [Figure 6A]

[0019] 1A-1C are cross-sectional views of LED chips illustrating differences in height or thickness between respective LED chip substrates that may be used to improve uniformity of light emission height in accordance with the principles of the present disclosure. [Figure 6B] 1A-1C are cross-sectional views of LED chips illustrating differences in height or thickness between respective LED chip substrates that may be used to improve uniformity of light emission height in accordance with the principles of the present disclosure. [Figure 6C]1A-1C are cross-sectional views of LED chips illustrating differences in height or thickness between respective LED chip substrates that may be used to improve uniformity of light emission height in accordance with the principles of the present disclosure. [Figure 7A]

[0020] FIG. 1 is a top view of an LED package in which multiple LED chips are assembled close to each other on a submount with improved uniformity of light emission height. [Figure 7B]

[0021] 7B is a cross-sectional view of an LED package along section line 7B-7B of FIG. 7A, including a first LED chip with a first luminescent material and a second LED chip with a second luminescent material. [Figure 7C]

[0022] 7C is a cross-sectional view of the LED package along section line 7C-7C of FIG. 7A, including a second LED chip and a third LED chip. [Figure 7D]

[0023] 7D is a cross-sectional view of the LED package taken along section line 7D-7D of FIG. 7A, including a third LED chip and a fourth LED chip. [Figure 8]

[0024] 1A-1C illustrate an example manufacturing sequence for improving the uniformity of the emission height between a first LED chip including a luminescent material and a second LED chip. [Figure 9]

[0025] 10A-10C illustrate another exemplary manufacturing sequence for improving the uniformity of the emission height between a first LED chip including a first luminescent material and a second LED chip including a second luminescent material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014]

[0026] The embodiments set forth below represent the necessary information to enable one skilled in the art to practice the embodiments and show the best way to practice the embodiments. Upon reading the following description in conjunction with the accompanying drawings, one skilled in the art will understand the concepts of the present disclosure and will recognize applications of these concepts not specifically addressed herein. It is to be understood that these concepts and applications are within the scope of the present disclosure and the appended claims.

[0015]

[0027] In this specification, terms such as first, second, etc. may be used to describe various elements, but it will be understood that these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element can be referred to as a second element, and similarly, a second element can be referred to as a first element, without departing from the scope of the present disclosure. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0016]

[0028] When an element, such as a layer, region, or substrate, is referred to as being "on" or extending "over" another element, it will be understood that the element can be directly on or extending over the other element, or there may be intervening elements. In contrast, when an element is referred to as being "directly on" or extending "directly over" another element, there are no intervening elements. Similarly, when an element, such as a layer, region, or substrate, is referred to as being "above" or extending "over" another element, it will be understood that the element can be directly on or extending directly over the other element, or there may be intervening elements. In contrast, when an element is referred to as being "directly on" or extending "directly over" another element, there are no intervening elements. Also, when an element is referred to as being "connected" or "coupled" to another element, it will be understood that the element can be directly connected or coupled to the other element, or there may be intervening elements. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

[0017]

[0029] Relative terms such as "bottom" or "top" 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 illustrated 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 shown in the figures.

[0018]

[0030] The terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural unless the context clearly indicates otherwise. Furthermore, it will be understood that the terms "comprises," "comprising," "including," and / or "comprising" as used herein specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0019]

[0031] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which this disclosure belongs. Furthermore, terms used herein should be interpreted as having a meaning consistent with the meaning in the context of this specification and related art, and will not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0020]

[0032] The embodiments are described herein with reference to schematic diagrams of embodiments of the present disclosure. Thus, the actual dimensions of layers and elements may vary and variations from the shapes of the figures are expected, for example, as a result of manufacturing techniques and / or tolerances. For example, a region illustrated or described as a square or rectangle may have rounded or curved features, and a region illustrated as a straight line may have some irregularities. Thus, the regions illustrated in the figures are schematic, and the shapes of the regions are not intended to illustrate the exact shape of the regions of the device, and are not intended to limit the scope of the disclosure. In addition, the size of structures or regions may be exaggerated relative to other structures or regions for illustrative purposes, and thus are provided to illustrate the general structure of the subject matter of the present invention, and may or may not be drawn to scale. Elements common between the figures may be indicated herein with common element numbers and may not be described again later.

[0021]

[0033] The embodiments disclosed herein relate to light emitting diode (LED) packages, and more particularly, to luminous height arrangements in LED packages, and related devices and methods. Disclosed are LED package, LED chip, and related device arrangements that include various combinations of LED chip types, luminous materials, and / or cover structures arranged together while also providing a substantially uniform luminous height for the corresponding luminous surfaces. The LED chips may be configured with different heights or thicknesses that compensate for variations in the luminous materials and / or cover structures utilized to provide different luminous colors. In this manner, LED packages and / or LED chips having different luminous colors may be assembled in close proximity to one another to improve luminous height uniformity.

[0022]

[0034] Before delving into the specific details of the various aspects of the present disclosure, an overview of the various elements that may be included in an exemplary LED of the present disclosure is provided for context. An LED chip typically comprises an active LED structure or region that may have many different semiconductor layers arranged in different ways. The fabrication and operation of LEDs and their active structures are generally known in the art and will be briefly discussed herein. The layers of the active LED structure can be fabricated using known processes with a suitable process being fabrication using metal organic chemical vapor deposition. The layers of the active LED structure can comprise many different layers, and generally comprise an active layer sandwiched between n-type and p-type oppositely doped epitaxial layers, all of which are formed in succession on a growth substrate. It is understood that the active LED structure can also include additional layers and elements, such as, but not limited to, buffer layers, nucleation layers, superlattice structures, undoped layers, cladding layers, contact layers, current spreading layers, light extraction layers and elements. The active layer can comprise a single quantum well, multiple quantum wells, double heterostructure, or superlattice structure.

[0023]

[0035] The active LED structure can be fabricated from different material systems, some of which are III-nitride based material systems. III-nitrides refer to semiconductor compounds formed between nitrogen (N) and elements in group III of the periodic table, usually aluminum (Al), gallium (Ga), and indium (In). Gallium nitride (GaN) is a common binary compound. III-nitrides also refer to ternary and quaternary compounds such as aluminum gallium nitride (AlGaN), indium gallium nitride (InGaN), and aluminum indium gallium nitride (AlInGaN). For III-nitrides, silicon (Si) is a common n-type dopant, and magnesium (Mg) is a common p-type dopant. Thus, the active layer, n-type layer, and p-type layer may include one or more layers of GaN, AlGaN, InGaN, and AlInGaN, undoped or doped with Si or Mg, for III-nitride based material systems. Other material systems include silicon carbide (SiC), organic semiconductor materials, and other III-V systems such as gallium phosphide (GaP), gallium arsenide (GaAs), indium phosphide (InP), and related compounds.

[0024]

[0036] The active LED structure may be grown on a growth substrate, which can include many materials, such as sapphire, SiC, aluminum nitride (AlN), GaN, GaAs, glass, or Si. SiC has certain advantages, such as a closer crystal lattice match with III-nitrides than other substrates, resulting in high-quality III-nitride films. SiC also has very high thermal conductivity, so the total output power of III-nitride devices on SiC is not limited by the heat dissipation of the substrate. Sapphire is another common substrate for III-nitrides, and also has certain advantages, such as low cost, well-established manufacturing processes, and excellent optical properties of light transmission.

[0025]

[0037] Different embodiments of the active LED structure can emit different wavelengths of light depending on the composition of the active layer, the n-type layer, and the p-type layer. In some embodiments, the active LED structure emits blue light with a peak wavelength range of about 430 nanometers (nm) to 480 nm. In other embodiments, the active LED structure emits green light with a peak wavelength range of 500 nm to 570 nm. In other embodiments, the active LED structure emits red light with a peak wavelength range of 600 nm to 650 nm. In certain embodiments, the active LED structure may be configured to emit light outside the visible spectrum, including one or more portions of the ultraviolet (UV) spectrum. The UV spectrum is typically divided into three wavelength range categories, designated by the letters A, B, and C. Thus, UV-A light is typically defined as a peak wavelength range of 315 nm to 400 nm, UV-B is typically defined as a peak wavelength range of 280 nm to 315 nm, and UV-C is typically defined as a peak wavelength range of 100 nm to 280 nm. UV LEDs are particularly important for use in applications related to disinfection of microorganisms in air, water, surfaces, etc. In other applications, the UV LED may be provided with one or more luminescent materials to provide an LED package with aggregate emission having a broad spectrum and improved color quality for visible light applications.

[0026]

[0038] The LED chip may also be coated with one or more luminescent materials (also referred to herein as luminescent bodies), such as phosphors, such that at least a portion of the light from the LED chip is absorbed by the one or more luminescent bodies and converted to one or more different wavelength spectra according to the characteristic emission from the one or more luminescent bodies. In this regard, the at least one luminescent body that receives at least a portion of the light generated by the LED light source may re-emit light having a different peak wavelength than the LED light source. The LED light source and the one or more luminescent materials may be selected such that their combined output is light having one or more desired characteristics, such as color, color point, intensity, spectral density, etc. In certain embodiments, the collective emission of the LED chips, optionally in combination with one or more luminescent materials, may be arranged to provide cool white, neutral white, or warm white light, such as within a color temperature range of 2500 Kelvin (K) to 10,000 K. In certain embodiments, luminescent materials having peak wavelengths of cyan, green, amber, yellow, orange, and / or red may be used. In certain embodiments, the LED chip in combination with one or more light emitters (e.g., phosphors) emits a combination of nearly white light. The one or more phosphors may be yellow (e.g., YAG:Ce), green (e.g., LuAg:Ce), and red (e.g., Ca i-x-y Sr x EU y In other embodiments, the LED chip and corresponding luminescent material may be configured to emit primarily light converted from the luminescent material, such that the aggregate emission contains little or no perceptible emission corresponding to the LED chip itself.

[0027]

[0039] The luminescent material described herein may be or include one or more of phosphors, scintillators, luminescent inks, quantum dot materials, day glow tape, and the like. The luminescent material may be provided by any suitable means, such as, for example, directly coated on one or more surfaces of the LEDs, dispersed in an encapsulant 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, and the like). In certain embodiments, the luminescent material may be downconverted or upconverted, or a combination of both downconverting and upconverting materials may be provided. In certain embodiments, a plurality of different (e.g., compositionally different) luminescent materials arranged to generate different peak wavelengths may be arranged to receive the emitted light from one or more LED chips. The one or more luminescent materials may be provided on one or more portions of the LED chip in various configurations. In certain embodiments, the luminescent material may be provided on one or more surfaces of the LED chip, while other surfaces of such LED chips may be free of luminescent material. In certain embodiments, the top surface of the LED chip may include luminescent material, while one or more side surfaces of the LED chip may be free of luminescent material. In certain embodiments, all or substantially all outer surfaces of the LED chip (e.g., other than the contact defining or mounting surfaces) may be coated or covered with one or more luminescent materials. In certain embodiments, the one or more luminescent materials may be disposed in a substantially uniform manner on or over one or more surfaces of the LED chip. In other embodiments, the one or more luminescent materials may be disposed in a non-uniform manner on or over one or more surfaces of the LED chip with respect to one or more of material composition, concentration, and thickness. In certain embodiments, the fill factor of the one or more luminescent materials may vary on or between one or more outer surfaces of the LED chip.In certain embodiments, one or more luminescent materials may be patterned on a portion of one or more surfaces of the LED chip to include one or more stripes, dots, curves, or polygonal shapes. In certain embodiments, multiple luminescent materials may be disposed in different separate regions or separate layers on or above the LED chip.

[0028]

[0040] In certain embodiments, one or more luminescent materials may be provided as at least a portion of a wavelength converting element or cover structure provided above the LED chip. The wavelength converting element or cover structure may include a support element and one or more luminescent materials provided by any suitable means, such as coating a surface of the support element or incorporating the luminescent material within the support element. In some embodiments, the support element may be comprised of a transparent material, a semi-transparent material, or a light-transmitting material such as sapphire, SiC, silicone, and / or glass (e.g., borosilicate and / or fused silica). The wavelength converting elements and cover structures of the present disclosure may be formed from a bulk material that is optionally patterned and then singulated. In certain embodiments, the patterning may be performed by an etching process (e.g., wet or dry etching) or by another process that modifies the surface, such as a laser or saw. In certain embodiments, the wavelength converting elements and cover structures may be thinned before or after the patterning process is performed. In certain embodiments, the wavelength converting elements and cover structures may include a substantially planar top surface that corresponds to the light-emitting area of ​​the LED package.

[0029]

[0041] The wavelength converting element and cover structure may be attached to one or more LED chips, for example, using a layer of transparent adhesive. In certain embodiments, the layer of transparent adhesive may include a silicone having a refractive index in the range of about 1.3 to about 1.6, lower than the refractive index of the LED chip on which the wavelength converting element is disposed. In various embodiments, the wavelength converting element may comprise a configuration such as a phosphor-in-glass or ceramic phosphor plate arrangement. A phosphor-in-glass or ceramic phosphor plate arrangement may be formed by mixing phosphor particles with a glass frit or ceramic material, pressing the mixture into a planar shape, and firing or sintering the mixture to form a hardened structure that can be cut or separated into individual wavelength converting elements.

[0030]

[0042] As used herein, a layer or region of a light emitting device may be considered to be "transparent" if at least 80% of the light emission that strikes the layer or region passes through the layer or region to emerge. Additionally, as used herein, a layer or region of an LED may be considered to be "reflective" or embody a "mirror" or "reflector" if at least 80% of the light emission that strikes the layer or region is reflected. In some embodiments, the light emission comprises visible light, such as blue and / or green LEDs, with or without luminescent materials. In other embodiments, the light emission may comprise non-visible light. For example, for GaN-based blue and / or green LEDs, silver (Ag) may be considered a reflective material (e.g., at least 80% reflective). For UV LEDs, appropriate materials may be selected to achieve a desired, in some embodiments, high reflectivity, and / or a desired, in some embodiments, low absorption. In certain embodiments, a "light-transmissive" material may be configured to transmit at least 50% of the light emission of a desired wavelength.

[0031]

[0043] The present disclosure may be useful for LED chips having various geometries, such as vertical and horizontal geometries. Vertically shaped LED chips typically include anode and cathode connections on opposite sides or surfaces of the LED chip. Horizontally shaped LED chips typically include both anode and cathode connections on the same side of the LED chip opposite a substrate, such as a growth substrate. In certain embodiments, the horizontally shaped LED chips may be mounted to a submount of an LED package, with the anode and cathode connections on a surface of the LED chip opposite the submount. In this configuration, wire bonds may be used to provide electrical connection between the anode and cathode connections. In other embodiments, the horizontally shaped LED chips may be flip-chip mounted to a surface of a submount of an LED package, with the anode and cathode connections on a surface of the active LED structure adjacent to the submount. In this configuration, electrical traces or patterns may be provided on the submount to provide electrical connection 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 submount of the LED package. Thus, light emitted from the active LED structure may pass through the substrate in a desired light emission direction. In other embodiments, the active LED structure may be bonded to a carrier submount and the growth substrate may be removed so that light may emit from the active LED structure without passing through the growth substrate.

[0032]

[0044] According to aspects of the present disclosure, the LED package may include one or more elements, such as a light-emitting material, an encapsulant, a light-altering material, a lens, and electrical contacts, provided with one or more LED chips. In certain aspects, the LED package may include a support member, such as a submount or a lead frame. Suitable materials for the submount include, but are not limited to, ceramic materials, such as aluminum oxide, alumina, AlN, or organic insulators, such as polyimide (PI) or polyphthalamide (PPA). In other embodiments, the submount may comprise a printed circuit board (PCB), sapphire, Si, or other suitable materials. In PCB embodiments, different PCB types may be used, such as standard FR-4 PCB, metal core PCB, or other types of PCB. In still further embodiments, the support structure may embody a lead frame structure. A light-altering material may be disposed within the LED package to reflect or otherwise direct light from one or more LED chips in a desired emission direction or pattern.

[0033]

[0045] Light modifying materials as used herein 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. The term "light reflective" as used herein refers to materials or particles that reflect, refract, scatter, or redirect light. In the case of light reflective materials, the light modifying materials may include at least one of fused silica, fumed silica, titanium dioxide (TiO2), or metal particles suspended in a binder such as silicone or epoxy. In certain aspects, the particles may have an index or refractive index configured to refract light emission in a desired direction. In certain aspects, light reflective particles may also be referred to as light scattering particles. The weight ratio of light reflective or scattering particles to binder may comprise a range of about 0.15:1 to about 0.5:1, or a range of about 0.5:1 to about 1:1, or a range of about 1:1 to about 2:1, depending on the desired viscosity before curing. In the case of light absorbing materials, the light modifying material may include at least one of carbon, silicon, or metal particles suspended in a binder, such as silicone or epoxy. The light reflective and light absorbing materials may comprise nanoparticles. In certain embodiments, the light modifying material may comprise a substantially white color to reflect and direct light. In other embodiments, the light modifying material may comprise a substantially opaque color, such as black or gray, to absorb light and enhance contrast. In certain embodiments, the light modifying material includes both light reflective and light absorbing materials suspended in a binder.

[0034]

[0046] LED packages have been developed with the ability to cluster multiple LED chips together to increase light output and / or emit multiple colors and / or peak wavelengths of light in a single LED package. The relative size or area of ​​the individual LED chips in the LED package may be selected depending on the desired light emission intensity and profile. In certain embodiments, the LED chips in the LED package may have a small size, such as 0.5 millimeters (mm) x 0.5 mm, and / or a large size, such as 2 mm x 2 mm, or other ranges from 0.5 mm x 0.5 mm to 1 mm x 1 mm. In certain embodiments, the longest lateral dimension of each LED chip may range from 0.5 mm to 2 mm, or from 1 mm to 2 mm, or from 0.5 mm to 1 mm. In such a range where at least one dimension is 0.5 mm or more, the LED chip may be well suited to provide high output in a compact footprint.

[0035]

[0047] For multi-color LED applications, multiple LED packages of different emitting colors may be mounted adjacent to each other on an underlying support element such as a printed circuit board to form a device. For other multi-color LED applications, multiple individually formed LED chips may be grouped into a single LED package. In either case, the individually formed LED chips may differ in size, shape, emission profile, and / or voltage requirements, especially for LED chips emitting light of different peak wavelengths. Such variations may lead to non-uniform emission, especially when various LED chips of different heights are placed adjacent to each other in individual LED packages or in a common LED package. If such variations are present, the emission height of the collective light-emitting surface collectively formed by the multiple LED chips may vary, leading to undesirable light emission non-uniformity. According to aspects of the present disclosure, arrangements of LED packages, LED chips, and related devices are provided in which different combinations of LED chip types, emitting materials, and cover structures are arranged together to also provide a substantially uniform emission height for the collective light-emitting surface.

[0036]

[0048] FIG. 1 is a top view of an LED package 10 including an LED chip 12 mounted on a submount 14 according to the principles of the present disclosure. A number of metal traces 16-1 to 16-2 are disposed on a first surface 14' of the submount 14 to provide electrical connection to the LED chip 12. The metal traces 16-1 to 16-2 may include any number of metals and / or metal layers, such as copper (Cu), nickel (Ni), palladium (Pd), gold (Au), or alloys thereof, patterned on the submount 14. Depending on the orientation of the LED chip 12, a number of wire bonds 18 may be employed to electrically connect the LED chip 12 to at least one of the metal traces 16-1 to 16-2. In certain embodiments, an electrical overstress device 20 may be provided on the metal traces 16-2 to provide electrical overload protection for the LED chip 12. The electrical overload device 20 may embody an electrostatic discharge chip and / or a Zener diode, and in a particular embodiment, the electrical overload device 20 may be electrically connected between the metal traces 16-1 and 16-2 via one of the wire bonds 18.

[0037]

[0049] The LED chips 12 may be configured to generate many different wavelengths of light depending on the application. For multi-color applications, several LED packages 10 may be provided in close proximity to one another as part of a larger device, with the LED chips 12 in each LED package 10 configured to generate different emission colors, either alone or in combination with luminescent materials. To generate different emission colors, the LED chips 12, and luminescent materials, if present, may be formed with structural differences, including dimensional variations, within each LED package 10. In this regard, the emission height within each LED package 10 may be different, thereby promoting aggregate emission non-uniformity when assembled in close proximity to one another.

[0038]

[0050] As used herein, the luminous height of an LED chip or LED package may be defined as the height of the top luminous surface measured from a lower mounting surface that is common to another LED chip or LED package. The top luminous surface may be defined as the top surface of the luminous element of the LED chip or LED package. The luminous element of the LED chip or LED package may be defined as the LED chip itself and / or any luminous material that may be present. For example, for an LED chip that does not include luminous material, the top luminous surface may be defined at the top surface of the LED chip. In another example, for an LED chip that includes luminous material on the LED chip, the top luminous surface may be defined at the top surface of the luminous material. In the context of an LED package, the luminous height may be measured as the vertical distance from the mounting surface of the LED package to the top luminous surface of the luminous element. In the context of a multi-chip LED package, the luminous height may be measured as the vertical distance from a mounting surface in the package that is common to multiple chips to the top luminous surface of the luminous element of each LED chip.

[0039]

[0051] According to aspects of the present disclosure, a luminous height arrangement of LED chips and / or LED packages of different emission types is provided to improve uniformity of the collective luminous height of the LED chips and / or LED packages. In certain aspects, the thickness of the LED chips and / or luminescent material layers may be provided at a predetermined value based on the intended arrangement of the LED chips in proximity to other LED chips, either in individual LED packages arranged together or in a common multi-chip LED package. In this manner, the luminous heights of the LED chips and / or LED packages of different emission types may be substantially the same, or within 25%, or within 10%, or within 5%, or within 1% of each other. In certain examples, the luminous heights of the LED chips and / or LED packages of different emission types may be substantially the same, or within 100 microns (μm), or within 75 μm, or within 60 μm, or within 30 μm, or within 15 μm of each other. Larger values, such as within 25% or within 100 μm, may be suitable for improving the uniformity of the emission height across many different types of LED chips and / or LED packages with many different types of emission colors. Larger values ​​may also be suitable for a small group of LED chips and / or LED packages, such as two different types with a large difference in emission color. In certain embodiments, smaller values, such as within 10% or within 30 μm, may be applicable to both many different types of emission colors and smaller group of LED chips and / or LED packages embodiments.

[0040]

[0052] 2 to 4 show that the LED packages 10-1 to 10-3 each have the same or similar luminous height H E 2 to 4 illustrate various embodiments of LED packages 10-1 to 10-3 configured to provide different emission colors or wavelengths while also providing a cross-section along the section line AA in FIG.

[0041]

[0053] FIG. 2 is a cross-sectional view of the LED package 10-1 taken along section line AA in FIG. 1 for an LED chip 12-1 including a light emitting material layer 22-1 disposed thereon. The LED package 10-1 includes an arrangement of mounting pads 24-1 to 24-2 on a second surface 14'' or mounting surface of the submount 14 opposite the first surface 14'. The mounting pads 24-1 to 24-2 may be electrically coupled to respective metal traces 16-1 to 16-2 through vias that extend through a portion of the submount 14 that is not visible in the cross-section of FIG. 2. In certain embodiments, the light emitting material layer 22-1 may be provided as a conformal coating over the LED chip 12-1 and a surface of the submount 14 adjacent to the LED chip 12-1. In other embodiments, the light emitting material layer 22-1 may be disposed directly above the LED chip 12-1. Above the light emitting material layer 22-1 and the LED chip 12-1 on the submount 14 may be an encapsulant 26 that is optically transmissive and / or optically transparent to the light from the LED chip 12-1 and / or the light emitting material layer 22-1. Many different materials may be used for the encapsulant 26, including silicone, plastic, epoxy, or glass, with a suitable material being compatible with the molding process.

[0042]

[0054] To provide a target color for the LED package 10-1, the luminescent material layer 22-1 is arranged to have a height H above the LED chip 12-1 that provides the appropriate wavelength conversion for the target color. 22-1 may be provided with a height H 22-1may be determined by any number of factors to provide a target color, such as the fill factor and / or particle size of the luminescent particles in the luminescent material layer 22-1. In a particular example, the LED package 10-1 may be configured to provide an emission color or color point corresponding to a nearly white light, such as warm white, neutral white, or cool white. In such an example, the LED chip 12-1 may be configured to provide light of blue wavelengths (e.g., 430 nm to 480 nm), and the luminescent material layer 22-1 may be configured to provide one or more of cyan, green, amber, yellow, orange, and / or red peak wavelengths when combined with the blue wavelengths of the LED chip 12-1 to provide an aggregate white emission. In another example, the LED package 10-1 may be configured to provide a saturated color target where the aggregate emission is substantially provided by the luminescent material layer 22-1. For example, the luminescent material layer 22-1 may be provided with a fill factor such that a substantial majority of the emission from the LED chip 12-1 is subject to wavelength conversion. In this regard, the collective emission from the LED package 10-1 is provided in a color that is substantially wavelength converted light. For example, the LED package 10-1 may be configured to provide an emission color or color point that is primarily cyan, green, amber, yellow, orange, red, or mint emission, among others. The emission height H of the LED package 10-1 E may be defined as the vertical distance from the bottom or mounting surface of the mounting pads 24-1, 24-2 to the top surface of the light emitting material layer 22-1. As illustrated, the light emitting height H E represents the height H of the light emitting material layer 22-1 in addition to the submount 14, the metal traces 16-1, 16-2, and the mounting pads 24-1, 24-2. 22-1 and the height H of LED chip 12-1 12-1 If the mounting pads 24-1, 24-2 are not present on the second surface 14″ of the submount 14, the emission height H E may be defined as the vertical distance from the second surface 14'', or mounting surface, of the submount 14 to the top surface of the light emitting material layer 22-1.

[0043]

[0055] 3 is a cross-sectional view of another arrangement of LED package 10-2 along section line AA of FIG. 1 that provides a different emission color than LED package 10-1 of FIG. 2. LED package 10-2 may be similar to LED package 10-1 of FIG. 2, but the combination of LED chip 12-2 and luminescent material layer 22-2 provides a different emission color or color point. For example, LED chip 12-2 may be configured to provide light in a blue wavelength (e.g., 430 nm to 480 nm), and luminescent material layer 22-2 may be configured to provide one or more of cyan, green, amber, yellow, orange, and / or red peak wavelengths that, when combined with the blue wavelength of LED chip 12-2, provide a different aggregate emission than LED package 10-1 of FIG. 2. In certain embodiments, the height H of luminescent material layer 22-2 above LED chip 12-2 may be 0.1 mm or less. 22-2 is the height H of the light emitting material layer 22-1 in FIG. 22-1 According to the principles of the present disclosure, the light emission height H E The LED chip 12-2 has a height H of the LED chip 12-1 in FIG. 12-1 Height H is higher than 12-2 may be provided.

[0044]

[0056] FIG. 4 is a cross-sectional view of another arrangement of the LED package 10-3 along the section line AA in FIG. 1, which provides a different emission color or color point than the LED package 10-1 in FIG. 2 and the LED package 10-2 in FIG. 3. In FIG. 4, the LED package 10-3 does not include a luminescent material layer. In this regard, the emission from the LED package 10-3 is generated only by the LED chip 12-3, which provides a monochromatic emission, such as a blue wavelength (e.g., 430 nm to 480 nm), or a green wavelength (e.g., 500 nm to 570 nm), or a red wavelength (e.g., 600 nm to 650 nm). The above wavelength ranges are provided as examples, and in practice, the LED chip 12-3 may be configured to emit light of any wavelength depending on the application. Due to the absence of a luminescent material layer, the emission height H Eis defined as the vertical distance from the bottom of the mounting pads 24-1, 24-2, or from the second face 14'' to the top surface of the LED chip 12-3 if the mounting pads 24-1, 24-2 are not present. E 2 and the LED package 10-2 in FIG. 3, the height H 12-3 is the height H of both the LED chips 12-1 and 12-2 in FIG. 3 and FIG. 4. 12-1 , H 12-2 It may be larger than that.

[0045]

[0057] 5 is a cross-sectional view of a light emitting device 28 including each of LED packages 10-1 to 10-3 of FIGS. 2 to 4. Light emitting device 28 may embody a lighting fixture or lighting module, which may be incorporated into a larger lighting system. LED packages 10-1 to 10-3 may be mounted adjacent to one another on a support element 30, such as a printed circuit board. In accordance with the principles of the present disclosure, the relative heights H of LED chips 12-1 to 12-3 are 12-1 from height H 12-3 , or thickness is the common light-emitting height H E Based on the target emission color of each of the LED packages 10-1 to 10-3, the height H of the LED chips 12-1 to 12-3 is specifically selected to compensate for the difference in the luminescent material layers 22-1, 22-3 so as to provide 12-1 from height H 12-3 The difference in height H of the LED chip 12-1 may exceed the normal variation in chip height. 12-1 is the height H of the LED chip 12-3 12-3 The height H of the LED chip 12-2 may be in the range of 45% to 65% of the 12-2 is the height H of the LED chip 12-3 12-3 In a specific example, the height H of the LED chip 12-1 may be in the range of 65% to 85%. 12-1may be provided in the range of 120 μm to 140 μm, and the height H 12-2 may be provided in the range of 155 μm to 175 μm, and the height H 12-3 may be provided in the range of 215 μm to 235 μm. In certain embodiments, each of the height differences described above, either as percentages or actual values, may be applicable to embodiments in which each of the LED chips 12-1 to 12-3 is configured to emit light of the same or similar wavelengths, such as in the range of 430 nm to 480 nm. In such embodiments, the difference in the emission provided by each of the LED packages 10-1 to 10-3 may be provided by differences in the luminescent material layers 22-2, 22-3 in the LED packages 10-1, 10-2 and the absence of luminescent material in the LED package 10-3. In other embodiments, one or more of the LED chips 12-1 to 12-3 may be configured to emit an emission wavelength that is different from one or more of the other LED chips 12-1 to 12-3.

[0046]

[0058] In Figure 5, the emission height H E is illustrated as being the same across each of the LED packages 10-1 to 10-3, there may be slight variations, improving the uniformity of the overall light emitting surface of the light emitting device 28. Thus, the light emitting height H E may be substantially the same across each of the LED packages 10-1 to 10-3, or within 25%, or within 10%, or within 5%, or within 1%. E may be substantially the same across each of the LED packages 10-1 to 10-3, or within 100 μm, or within 75 μm, or within 60 μm, or within 30 μm, or within 15 μm. FIG. 5 shows that the three LED packages 10-1 to 10-3 of different emission colors have the same or similar emission heights H EAlthough an example consisting of is illustrated, the principles described herein are applicable to many combinations of LED packages providing many different emission colors. For example, in certain embodiments, at least 2, or at least 5, or at least 10, or at least 15, or at least 20, or in the range of 2 to 20, or in the range of 5 to 20, different LED packages, each configured to provide a different target emission color, may be arranged to have emission heights that are substantially the same, or within 25% of each other, or within 10% of each other, or within 5% of each other, or within 1% of each other, or within 100 μm of each other, or within 75 μm of each other, or within 60 μm of each other, or within 30 μm of each other, or within 15 μm of each other.

[0047]

[0059] In certain aspects, the height difference between the LED chips may be predetermined based on the target emission color of the LED package in which the LED chips are provided. As noted above, certain embodiments include LED chips configured to emit the same emission color disposed with different luminescent materials in different LED packages or in an LED package without luminescent materials. In other embodiments, the LED chips may be configured to emit different emission colors. In either case, the height difference between the LED chips may be provided before the LED chips are mounted in their respective LED packages. In certain embodiments, the height difference may be provided by removing and / or thinning certain portions of the LED chips, such as the LED chip substrate, by different amounts from one another. As used herein, the LED chip substrate may refer to the growth substrate on which the active LED structure is epitaxially grown. In another example, the LED chip substrate may generally refer to the host substrate on which the active LED structure is supported when the growth substrate is removed.

[0048]

[0060] 6A to 6C show the height H between the LED chip substrate 32-1 and the LED chip substrate 32-3. 32-1 from height H 32-36A to 6C are cross-sectional views of LED chips 12-1 to 12-3 illustrating the thickness difference between the active LED structures 31-1 to 31-3. In each of FIGS. 6A to 6C, the active LED structures 31-1 to 31-3 are generally illustrated on the bottom surface of the LED chip substrates 32-1 to 31-3, as is typical for flip-chip mounting. However, the principles described herein are applicable to other chip configurations, such as arrangements in which the LED chip substrates 32-1 to 32-3 are closer to the mounting surface than the active LED structures 31-1 to 31-3. As illustrated, the height H 32-1 is the height H of the LED chip board 32-2 32-2 The height H of the LED chip substrate 32-2 is smaller than 32-2 is the height H of the LED chip board 32-3 32-3 During the manufacturing of the LED chips 12-1 to 12-3, a thinning and / or planarization step applied to the LED chip substrates 32-1 to 32-3 may be performed to provide the height difference described above based on the intended color target of each of the LED chips 12-1 to 12-3. In a particular embodiment, at least two of the LED chips 12-1 to 12-3 may include the same type of active LED structure 31-1 to 31-3 configured to generate the same wavelength of light. The height H described above may be smaller than the height H 32-1 from height H 32-3 By providing a difference, each of LED chips 12-1 to 12-3 may be provided with a different amount of luminescent material or no luminescent material at all, thereby providing an overall different emission while at the same time providing a uniform emission height for LED chips 12-1 to 12-3.

[0049]

[0061] Although the above examples are provided in the context of different LED packages arranged with the same or similar luminous height, the principles described herein are also applicable to a single LED package including multiple LED chips of different luminous colors. In this regard, a multi-chip LED package may be arranged with LED chips of different luminous colors and / or different arrangements of luminescent materials to provide the same or similar luminous height within the multi-chip LED package.

[0050]

[0062] 7A is a top view of an LED package 34 in which multiple LED chips 12-1 to 12-4 are assembled adjacent to one another on a submount 14. The LED chips 12-1 to 12-4 may include various combinations of chip types and / or LED chip orientations. For example, the different chip types may include a first LED chip 12-1 and corresponding luminescent material, a second LED chip 12-2 and corresponding luminescent material that provides a different color of light than the first LED chip 12-1, and a third LED chip 12-3 and a fourth LED chip 12-4 that do not include corresponding luminescent material. It is believed that the principles described herein are applicable to many different combinations of chip types in an LED package 34. Although only four LED chips 12-1 to 12-4 are illustrated, the disclosed principles are applicable to any number of LED chips in a common package, including at least 2, or at least 5, or at least 10, or at least 15, or at least 20, or in the range of 2 to 20, or in the range of 5 to 20, different LED chips in the LED package 34, each LED chip being configurable to provide a different target emission color. When assembled together according to the present disclosure, the LED package 34 may be arranged to have an emission height with improved uniformity. For example, the individual emission heights of each LED chip 12-1 to 12-4 may be substantially the same, or within 25%, or within 10%, or within 5%, or within 1%, or within 100 μm, or within 75 μm, or within 60 μm, or within 30 μm, or within 15 μm of each other. In certain embodiments, the different chip types may include different structures and / or orientations of the LED chips 12-1 to 12-4. For example, the third LED chip 12-3 may be arranged in a vertical orientation with electrical connections made on opposite sides, while LED chip 12-1, LED chip 12-2, and LED chip 12-4 may be arranged in a flip-chip orientation with electrical connections made from the same side at the interface with submount 14.

[0051]

[0063] The LED package 34 may further include a light-modifying material 36 disposed to cover a portion of the submount 14 outside the LED chips 12-1 to 12-4. The light-modifying material 36 may be formed of a light-reflective material and / or a light-refractive material such that light from the LED chips 12-1 to 12-4 may be directed toward a desired light-emitting direction of the LED package 34 while reducing light loss. In certain embodiments, the light-modifying material 36 may be configured with a substantially white color. As illustrated, the light-modifying material 36 is disposed to extend from a peripheral edge of the submount 14 to the peripheral edge of each of the LED chips 12-1 to 12-4 and between adjacent LED chips of the LED chips 12-1 to 12-4. In this regard, a collective light-emitting surface of the LED package 34 may be collectively formed by the top surfaces of the LED chips 12-1 to 12-4. 7A , various of the electrical overload elements 20 may be visible, but the light-modifying material 36 may be disposed over them on the submount 14. The polarity indicators 38 may be etched or otherwise formed in the surface of the light-modifying material 36. In other embodiments, the polarity indicators 38 may be omitted or may be formed in a different portion of the LED package 34, such as on the surface of the submount 14.

[0052]

[0064] FIG. 7B is a cross-sectional view of the LED package 34 along the section line 7B-7B of FIG. 7A, including a first LED chip 12-1 with a first light-emitting material layer 22-1 and a second LED chip 12-2 with a second light-emitting material layer 22-2. In certain embodiments, the LED chips 12-1, 12-2 and the corresponding light-emitting material layers 22-1, 22-2 may be configured to provide different light-emitting colors, such as white light of different color temperatures or at least one saturated color. In this regard, the height or thickness of the first light-emitting material layer 22-1 may be greater than the height or thickness of the second light-emitting material layer 22-2. As mentioned above, the height or thickness of each LED chip 12-1, 12-2 may be predetermined with different values ​​such that the light-emitting heights including the LED chips 12-1, 12-2 and the corresponding light-emitting material layers 22-1, 22-2 are the same or similar. As illustrated, the light-modifying material 36 may cover each side of the LED chips 12-1, 12-2 and each side of the light-emitting material layers 22-1, 22-2. In certain embodiments, the light-modifying material 36 may further be disposed between the LED chips 12-1, 12-2 and between the light-emitting material layers 22-1, 22-2. The encapsulant 26 may be disposed over the light-emitting material layers 22-1, 22-2 and the light-modifying material 36, and in certain embodiments, the encapsulant 26 may extend entirely to be aligned with a periphery of the submount 14.

[0053]

[0065] 7C is a cross-sectional view of the LED package 34 along section line 7C-7C of FIG. 7A, including the second LED chip 12-2 and the third LED chip 12-3. In certain embodiments, the third LED chip 12-3 may not have any luminescent material associated therewith, so that the third LED chip 12-3 is configured to provide monochromatic emission. As illustrated, the height or thickness of the LED chips may be pre-determined at different values, with the luminescent heights described above being the same or similar.

[0054]

[0066] FIG. 7D is a cross-sectional view of the LED package 34 along the section line 7D-7D of FIG. 7A, including the third LED chip 12-3 and the fourth LED chip 12-4. In certain embodiments, the fourth LED chip 12-4 may include a chip cover 40 provided on its upper surface. As used herein, the chip cover 40 may also be referred to as a cover structure. As illustrated, the height of the chip cover 40 may be selected to be formed at the same or similar height as the light-emitting height of the third LED chip 12-3. In certain embodiments, the chip cover 40 may include a light-emitting material. For example, the chip cover 40 may embody a phosphor-in-glass structure, a ceramic phosphor plate, or a phosphor-in-cured silicone structure. In other embodiments, the chip cover 40 may embody a light-transmitting or light-transparent cover, such as glass or silicone. In yet another embodiment, the chip cover 40 may embody a light-transmitting or light-transparent cover with a layer of light-emitting material formed thereon.

[0055]

[0067] Although the LED package 34 is described in the context of a multiple chip package, the principles described are also applicable to an embodiment in which each of the LED chips 12-1 to 12-4 is disposed alone within the package, along with all other elements described for the LED package 34. In this regard, the principles described for Figs. 7A to 7D are applicable to provide a separate package for each LED chip 12-1 to 12-4, such that the luminous height between the different packages is the same or similar, as described above. Thus, each separate package will be the same as that illustrated for the LED package 34 with only one of the LED chips 12-1 to 12-4. In yet another embodiment, two different LED packages may be provided, each with a different thickness of the chip cover 40, to provide the same or similar luminous height.

[0056]

[0068] As illustrated in Figures 7A-7D, the LED package 34 may be provided with different LED chips 12-1 to 12-4 providing different emission colors, but with the same or similar overall emission height of the LED package 34. Differences in the luminescent material layers 22-1, 22-2, and lack thereof, may be accommodated by providing a predetermined thickness for each of the LED chips 12-1 to 12-4. In this regard, the common emission height of the LED package 34 may provide an aggregate emission with improved uniformity and color mixing.

[0057]

[0069] Various manufacturing sequences may be implemented to provide uniform emission height for LED chips and / or LED packages of different emission colors. Figures 8 and 9 depict exemplary manufacturing sequences for reducing the thickness of LED chips based on a target color point for improved emission height uniformity.

[0058]

[0070] FIG. 8 illustrates an exemplary fabrication sequence 42 for improving the uniformity of the emission height between a first LED chip including a luminescent material and a second LED chip. In a first step 44, a first color point is provided or determined based on the light output intended for the first LED chip and the luminescent material. The first LED chip and the luminescent material may embody either the LED chip 12-1 and the luminescent material layer 22-1 of FIG. 2, the LED chip 12-2 and the luminescent material layer 22-2 of FIG. 3, or the LED chips 12-1, 12-2 of FIG. 7A-7D. The first color point may determine the amount or thickness of the corresponding luminescent material provided on the first LED chip. In a second step 46, a second color point is provided based on the light output of the second LED chip. In certain embodiments, the second color point may correspond to the emission generated by the active LED structure of the second LED chip. In this manner, the second LED chip may be free of a corresponding luminescent material. For example, the second LED chip may embody the LED chip 12-3 of FIG. 4, or either the LED chip 12-3 or the LED chip 12-4 of FIG. 7A-7D. In a third step 48, the thickness of one or more of the first LED chip and the second LED chip may be reduced such that the luminous height between the first LED chip and the second LED chip may be the same or similar as described above. In one example, both the first LED chip and the second LED chip may be formed with the same thickness, and then the thickness of the first LED chip may be reduced by an amount corresponding to the thickness of the corresponding luminescent material. In another example, the first LED chip and the second LED chip may be initially formed with different thicknesses. Thus, both the first LED chip and the second LED chip may have their respective thicknesses reduced by an amount that provides a uniform luminous height. In yet another example, a chip cover (e.g., 40 in FIG. 7D ) may be utilized alone or in combination with reducing the thickness of at least one of the first LED chip and the second LED chip to achieve the same or similar emission height.

[0059]

[0071] FIG. 9 illustrates another exemplary fabrication sequence 50 for improving the uniformity of the luminous height between a first LED chip including a first luminescent material and a second LED chip also including a second luminescent material. The first LED chip and corresponding first luminescent material and the second LED chip and corresponding second luminescent material may embody any of the LED chip 12-1 and luminescent material layer 22-1 of FIG. 2, the LED chip 12-2 and luminescent material layer 22-2 of FIG. 3, or the LED chips 12-1, 12-2 of FIG. 7A-7D. In a first step 52, a first color point is provided or determined based on the light output intended for the first LED chip and the first luminescent material. In a second step 54, a second color point is provided or determined based on the light output intended for the second LED chip and the second luminescent material. In a third step 56, the thickness of one or more of the first and second LED chips may be reduced such that the emission height between the first and second LED chips may be the same or similar as described above. In another example, a chip cover (e.g., 40 in FIG. 7D) may be utilized alone or in combination with reducing the thickness of at least one of the first and second LED chips to achieve the same or similar emission height.

[0060]

[0072] It is contemplated that any of the foregoing aspects, and / or various individual aspects and features described herein may be combined to further advantage. Any of the various embodiments disclosed herein may be combined with one or more of the other disclosed embodiments, unless otherwise indicated herein to the contrary.

[0061]

[0073] Those skilled in the art will recognize improvements and modifications to the preferred embodiments of the present disclosure, and all such improvements and modifications are considered to be within the scope of the concepts disclosed herein and the appended claims.

Claims

1. providing a first light emitting diode (LED) chip and a first layer of light emitting material defining a first color point; providing a second LED chip defining a second color point different from the first color point; reducing a thickness of at least one of the first LED chip and the second LED chip such that a first luminous height formed by the first LED chip and the first luminescent material layer is within 100 microns (μm) of a second luminous height of the second LED chip; A method comprising:

2. 2. The method of claim 1 , wherein the first emitting height is defined as the vertical distance from a mounting surface of a first LED package to a top emitting surface of the first LED package, and the second emitting height is defined as the vertical distance from a mounting surface of the second LED chip to a top emitting surface of the second LED chip.

3. 3. The method of claim 2 , wherein the top light-emitting surface of the first LED chip is defined at a top surface of the first light-emitting material layer, and the top light-emitting surface of the second LED chip is defined at a top surface of the second LED chip.

4. The method of claim 1 , wherein a thickness of the first LED chip is reduced by an amount corresponding to a thickness of the first light emitting material layer.

5. 2. The method of claim 1 , wherein reducing a thickness of at least one of the first LED chip and the second LED chip comprises reducing a thickness of a substrate of at least one of the first LED chip and the second LED chip.

6. The method of claim 1 , wherein the first emission height is within 60 μm of the second emission height.

7. The method of claim 1 , wherein the first emission height is within 30 μm of the second emission height.

8. providing a first light emitting diode (LED) chip and a first layer of light emitting material defining a first color point; providing a second LED chip and a second luminescent material layer defining a second color point different from the first color point; reducing a thickness of at least one of the first LED chip and the second LED chip such that a first emission height formed by the first LED chip and the first luminescent material layer is within 100 microns (μm) of a second emission height formed by the second LED chip and the second luminescent material layer; A method comprising:

9. 9. The method of claim 8, wherein the first emitting height is defined as the vertical distance from a mounting surface of the first LED chip to a top emitting surface of the first LED chip, and the second emitting height is defined as the vertical distance from a mounting surface of the second LED chip to a top emitting surface of the second LED chip.

10. 10. The method of claim 9, wherein the top light-emitting surface of the first LED chip is defined at a top surface of the first light-emitting material layer, and the top light-emitting surface of the second LED chip is defined at a top surface of the second light-emitting material layer.

11. 9. The method of claim 8, wherein reducing a thickness of at least one of the first LED chip and the second LED chip comprises reducing a thickness of a substrate of at least one of the first LED chip and the second LED chip.

12. The method of claim 8 , wherein the first emission height is within 60 μm of the second emission height.

13. The method of claim 8 , wherein the first emission height is within 30 μm of the second emission height.

14. A first light emitting diode (LED) package and a second LED package, The first LED package comprises: a first submount; a first LED chip on the first submount; a first light emitting material layer on the first LED chip, the first LED chip and the first light emitting material layer defining a first color point, a first light emitting height defined as a vertical distance from a mounting surface of the first LED package to a top light emitting surface of the first LED package; The second LED package includes: a second submount; and a second LED chip on the second submount, the second LED chip at least partially defining a second color point different from the first color point, a second emitting height defined as a vertical distance from a mounting surface of the second LED package to a top emitting surface of the second LED package; A light emitting device, wherein the first emission height is within 100 microns (μm) of the second emission height.

15. 15. The light emitting device of claim 14, wherein the first emission height is within 60 μm of the second emission height.

16. 15. The light emitting device of claim 14, wherein the first emission height is within 30 μm of the second emission height.

17. 15. The light emitting device of claim 14, wherein the top light emitting surface of the first LED package is defined at a top surface of the first light emitting material layer, and the top light emitting surface of the second LED package is defined at a top surface of the second LED chip.

18. 15. The light emitting device of claim 14, further comprising a second light emitting material layer on the second LED chip, the second LED chip and the second light emitting material layer defining the second color point, the top light emitting surface of the first LED package being defined at a top surface of the first light emitting material layer, and the top light emitting surface of the second LED package being defined at a top surface of the second light emitting material layer.

19. 15. The light emitting device of claim 14, wherein the first layer of light emitting material is provided as a coating on the first LED chip.

20. 15. The light emitting device of claim 14, wherein the first light emitting material layer is disposed on or in a chip cover attached to the first LED chip.

21. A submount and a first light emitting diode (LED) chip on the submount; a first luminescent material layer on the first LED chip, the first LED chip and the first luminescent material layer defining a first color point, a first luminescent height defined as the vertical distance from a mounting surface of the first LED chip to a top light emitting surface of the first LED chip; a second LED chip on the submount, the second LED chip at least partially defining a second color point different from the first color point, and a second emitting height defined as the vertical distance from a mounting surface of the second LED chip to a top emitting surface of the second LED chip; Equipped with 10. A light emitting diode (LED) package, wherein the first emitting height is within 100 μm of the second emitting height.

22. 22. The LED package of claim 21, wherein the first luminous height is within 60 μm of the second luminous height.

23. 22. The LED package of claim 21, wherein the first luminous height is within 30 μm of the second luminous height.

24. 22. The LED package of claim 21 , wherein the top light-emitting surface of the first LED chip is defined at a top surface of the first light-emitting material layer, and the top light-emitting surface of the second LED chip is defined at a top surface of the second LED chip.

25. 22. The LED package of claim 21, further comprising a second light emitting material layer on the second LED chip, the second LED chip and the second light emitting material layer defining the second color point, the top light emitting surface of the first LED chip being defined at a top surface of the first light emitting material layer, and the top light emitting surface of the second LED chip being defined at a top surface of the second light emitting material layer.

26. 22. The LED package of claim 21, wherein the first light emitting material layer is provided as a coating on the first LED chip.

27. 22. The LED package of claim 21, wherein the first light emitting material layer is disposed on or in a chip cover attached to the first LED chip.

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