Light-altering material arrangement for a light emitting device

Abstract

Solid state lighting devices and more particularly light emitting devices including light emitting diodes (LEDs) with light modifying material (20) arrangements are disclosed. LED devices (10) can include light modifying material (20) disposed around the peripheral sidewall (12c) of an LED chip (12) without the need for a supporting submount or leadframe. Light modifying material (20) of reduced thickness can be disposed along the peripheral sidewall (12c) of an LED chip (12). Exemplary LED devices (10) disclosed herein can be configured with a footprint that approximates the footprint of an LED chip (12) within the LED device (12) and can also provide an amount of light modifying material (20) around the peripheral edge of the LED chip (12) to reduce cross-talk. Thus, such LED devices (10) can be well suited for applications where LED devices (10) form closely spaced LED arrays. Manufacturing techniques including lamination of preformed sheets of light modifying material on one or more surfaces of an LED chip (12) are disclosed.

Description

Technical Field

[0001] This disclosure relates to solid-state lighting devices, and more specifically, to the arrangement of light-changing materials for light-emitting devices such as light-emitting diodes (LEDs). Background Technology

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

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

[0004] Typically, it is desirable to operate LEDs at the highest possible luminous efficiency, which can be measured by emission intensity (e.g., lumens per watt) related to output power. The practical goal of improving emission efficiency is to maximize the extraction of light emitted from the active region along the desired light propagation direction. The light extraction and external quantum efficiency of an LED can be limited by many factors, including internal reflection. According to Snell's law, photons arriving at the surface (interface) between the LED surface and its surroundings are either refracted or internally reflected. If photons are internally reflected in a repetitive manner, they will eventually be absorbed and will never provide visible light leaving the LED.

[0005] LED packages, modules, and mounting devices have been developed that can include multiple LED emitters arranged close together. In such applications, LED emitters can be provided to combine the emissions corresponding to each individual LED emitter to produce a desired light emission. To provide similar or different emission characteristics, emissions corresponding to each individual LED emitter can be selectively produced. When different LED emitters are positioned close together, producing high-quality light with the desired emission characteristics can be challenging. Furthermore, conventional packaging of LED emitters can further limit the spacing between individual LED emitters.

[0006] The field continues to seek improved LED and solid-state lighting devices with desired lighting characteristics that overcome the challenges associated with conventional lighting devices. Summary of the Invention

[0007] This disclosure relates to solid-state lighting devices, and more specifically, to the arrangement of light-modifying materials for light-emitting devices such as light-emitting diodes (LEDs). LED devices may include light-modifying materials disposed around the peripheral sidewalls of an LED chip without the need for a support base or lead frame. The light-modifying material, with decreasing thickness, may be disposed along the peripheral sidewalls of the LED chip. In this regard, the exemplary LED devices disclosed herein may be configured with a footprint close to the footprint of the LED chip within the LED device, while a certain amount of light-modifying material is disposed around the peripheral edge of the LED chip to reduce crosstalk. Therefore, such LED devices may be well-suited for applications where the LED device forms a closely spaced LED array. Manufacturing techniques are disclosed, including laminating a preform of the light-modifying material onto one or more surfaces of the LED chip.

[0008] In one aspect, an LED device includes: at least one LED chip, including a top surface, a bottom surface, and a peripheral sidewall combining the top and bottom surfaces; and a light-modifying material disposed on the peripheral sidewall of the at least one LED chip, the light-modifying material including a width measured from the peripheral sidewall, which is in the range of 15 micrometers (μm) to 100 μm. In some embodiments, the width of the light-modifying material is in the range of 15 μm to 50 μm. In some embodiments, the top surface of the at least one LED chip does not have light-modifying material. In some embodiments, the bottom surface of the at least one LED chip does not have light-modifying material. In some embodiments, the light-modifying material includes a light-reflecting material. In some embodiments, the light-reflecting material includes fused silica, fumed silica, or titanium dioxide (TiO2) particles suspended in silicone resin. In some embodiments, the light-modifying material includes a light-absorbing material. In some embodiments, the LED device does not have a base on the bottom surface of the at least one LED chip.

[0009] The LED device may further include an anode and a cathode located on the bottom surface of at least one LED chip. The LED device may further include a wavelength conversion element disposed on the top surface of at least one LED chip, the wavelength conversion element comprising at least one phosphor material. In some embodiments, the wavelength conversion element further includes a cover supporting at least one phosphor material. In some embodiments, the wavelength conversion element comprises one of: a ceramic phosphor plate, a phosphor in glass, and a phosphor embedded in silicon. In some embodiments, the peripheral sidewalls of the wavelength conversion element are offset from the peripheral sidewalls of at least one LED chip. In some embodiments, the light-changing material is conformal on the peripheral sidewalls of the wavelength conversion element and the peripheral sidewalls of at least one LED chip. In some embodiments, the light-changing material forms rounded corners at the peripheral edge corners of the wavelength conversion element.

[0010] In some embodiments, the light-changing material forms rounded corners at the peripheral sidewall corners of at least one LED chip. In some embodiments, the light-changing material forms extensions extending away from the peripheral sidewalls of at least one LED chip. In some embodiments, the LED device may further include a lens on at least one LED chip.

[0011] In another aspect, a method includes: providing at least one LED chip including a top surface, a bottom surface, and peripheral sidewalls combining the top and bottom surfaces; forming a light-changing material on the top surface and peripheral sidewalls of the at least one LED chip; and removing a portion of the light-changing material located on the top surface of the at least one LED chip. In some embodiments, forming the light-changing material includes laminating a preform of the light-changing material onto the top surface and peripheral sidewalls. In some embodiments, the light-changing material forms rounded corners at the corners of the peripheral sidewalls of the at least one LED chip.

[0012] The method may further include disposed of a wavelength conversion element on the top surface of at least one LED chip before forming the light-changing material. In some embodiments, removing a portion of the light-changing material located on the top surface of the at least one LED chip includes removing a portion of the light-changing material located on the top surface of the wavelength conversion element. In some embodiments, the light-changing material forms rounded corners at the peripheral edge corners of the wavelength conversion element. In some embodiments, the at least one LED chip includes a plurality of LED chips disposed on a common support. In some embodiments, forming the light-changing material includes laminating a preform of the light-changing material onto the top surface and peripheral sidewalls of each of the plurality of LED chips. The method may further include separating each of the plurality of LED chips from the common support.

[0013] On the other hand, to gain additional advantages, any of the foregoing aspects and / or the various individual aspects and features described herein may be combined. Unless otherwise stated herein, any of the various features and elements disclosed herein may be combined with one or more other disclosed features and elements.

[0014] Those skilled in the art will understand the scope of this disclosure and its additional aspects will become apparent upon reading the following detailed description of preferred embodiments in conjunction with the accompanying drawings. Attached Figure Description

[0015] The accompanying drawings, which are included in and form part of this description, illustrate several aspects of this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0016] Figure 1A This is a cross-sectional view of a light-emitting diode (LED) device based on the aspects disclosed herein.

[0017] Figure 1B yes Figure 1A A top view of the LED equipment.

[0018] Figure 1C yes Figure 1A Bottom view of the LED equipment.

[0019] Figure 2A yes Figure 1A A cross-sectional view of an LED equipment during the manufacturing process, showing the LED chip being attached to a temporary carrier.

[0020] Figure 2B yes Figure 1A A cross-sectional view of an LED manufacturing process, showing a wavelength conversion element attached to the top surface of an LED chip.

[0021] Figure 2C yes Figure 1A A cross-sectional view of an LED manufacturing process, showing a preform of light-changing material placed above the LED chip.

[0022] Figure 2D yes Figure 1A A cross-sectional view of an LED equipment during the manufacturing process, showing a preform of light-changing material located on the LED chip and wavelength conversion element.

[0023] Figure 2E yes Figure 1A A cross-sectional view of an LED device during the manufacturing process, in which light-changing materials are conformally laminated around the peripheral sidewalls of the wavelength conversion element and the peripheral sidewalls of the LED chip.

[0024] Figure 2F yes Figure 1AA cross-sectional view of an LED manufacturing process, showing the removal of some light-changing material from the top surface of the LED chip and the top surface of the wavelength conversion element.

[0025] Figure 2G yes Figure 1A A cross-sectional view of the LED equipment during the manufacturing process, showing the LED equipment separated from the temporary carrier.

[0026] Figure 3 It is similar to Figure 1A The image shows a cross-sectional view of an LED device, but the lateral dimension of the wavelength conversion element is smaller than that of the LED chip.

[0027] Figure 4 It is similar to Figure 1A The diagram shows a cross-sectional view of an LED device, but the wavelength conversion element is configured with the same lateral dimensions as the LED chip.

[0028] Figure 5 It is similar to Figure 4 A cross-sectional view of an LED device, but the order of the fluorescent materials and the covering of the wavelength conversion element are reversed.

[0029] Figure 6 It is similar to Figure 5 The image shows a cross-sectional view of an LED device, in which fluorescent material is incorporated throughout the wavelength conversion element.

[0030] Figure 7 It is similar to Figure 5 The image shows a cross-sectional view of an LED device, but the LED device does not contain fluorescent material.

[0031] Figure 8 It is similar to Figure 4 The image shows a cross-sectional view of an LED device, but no light-changing material is provided around the outer side of the wavelength conversion element.

[0032] Figure 9 It is similar to Figure 8 The image shows a cross-sectional view of an LED device, but the order of the fluorescent materials and the covering of the wavelength conversion elements are reversed.

[0033] Figure 10 It is similar to Figure 6 The diagram shows a cross-section of an LED device, but the wavelength conversion element is also located on the top surface of the light-changing material.

[0034] Figure 11 It is similar to Figure 7The image shows a cross-sectional view of an LED device, in which lenses are arranged on the top surface of the LED chip and the top surface of the light-changing material.

[0035] Figure 12 It is similar to Figure 11 The image shows a cross-sectional view of an LED device, in which a lens forms a curved surface above the LED chip.

[0036] Figure 13 It is similar to Figure 12 The image shows a cross-sectional view of an LED device, in which fluorescent material is applied to the surface of the lens.

[0037] Figure 14 It is similar to Figure 13 The image shows a cross-sectional view of an LED device, in which fluorescent material is embedded within a lens.

[0038] Figure 15 It is similar to Figure 14 The image shows a cross-sectional view of an LED device, but the lens does not contain fluorescent material.

[0039] Figure 16 It is similar to Figure 15 The diagram shows a cross-section of an LED device, with fluorescent material placed between the LED chip and the lens.

[0040] Figure 17 It is similar to Figure 16 The image shows a cross-sectional view of an LED device, in which fluorescent material is applied to the surface of the lens.

[0041] Figure 18 It is similar to Figure 14 The image shows a cross-sectional view of an LED device, but a lens is also placed on the top surface of the light-changing material.

[0042] Figure 19 It is similar to Figure 15 The image shows a cross-sectional view of an LED device, but a lens is also placed on the top surface of the light-changing material.

[0043] Figure 20 It is similar to Figure 4 The diagram shows a cross-sectional view of an LED device, but the light-changing material further includes an extension extending from the sidewall of the LED chip.

[0044] Figure 21 It is similar to Figure 4 The diagram shows a cross-sectional view of an LED device, but the light-changing material includes light-absorbing particles for enhancing contrast.

[0045] Figure 22 It is similar to Figure 21 The diagram shows a cross-section of an LED device, but the light-changing materials include light-absorbing particles and light-reflecting particles. Detailed Implementation

[0046] The embodiments described below represent essential information that enables those skilled in the art to practice the embodiments and illustrates the best mode of practicing the embodiments. Upon reading the following description with reference to the accompanying drawings, those skilled in the art will understand the concepts of this disclosure and recognize the application of these concepts not specifically mentioned herein. It should be understood that these concepts and applications fall within the scope of this disclosure and the appended claims.

[0047] It is understood that although the terms first, second, etc., can be used to describe various elements, 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 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 of the associated listed items.

[0048] It is understood that when a component such as a layer, region, or substrate is referred to as being "on" or "extending" to another component, it can be directly located on or directly extended to the other component, or there may be intermediate components. Conversely, when a component is referred to as being "directly located" or "directly extended" to another component, there are no intermediate components. Similarly, it is understood that when a component such as a layer, region, or substrate is referred to as being "on" or "extending" to another component, it can be directly on or directly extended to the other component, or there may be intermediate components. Conversely, when a component is referred to as being "directly covered" or "directly extended" to another component, there are no intermediate components. It should also be understood that when a component is referred to as being "connected" or "coupled" to another component, it can be directly connected to or coupled to the other component, or there may be intermediate components. Conversely, when a component is referred to as being "directly connected" or "directly coupled" to another component, there are no intermediate components.

[0049] In this document, relative terms such as “below” or “above” or “up” or “below” or “horizontal” or “vertical” may be used to describe the relationship between one element, layer, or region and another element, layer, or region, as shown in the figures. It will be understood that, in addition to the orientations shown in the figures, these terms and the terms discussed above are intended to cover different orientations of the device.

[0050] The terminology used herein is for describing particular embodiments only and is not intended to limit this disclosure. The singular forms “a,” “an,” and “the” as used herein also include the plural forms unless the context clearly indicates otherwise. It should be further understood that when the terms “comprising,” “including,” “containing,” and / or “comprising” are used herein, they specify the presence of the stated feature, integer, step, operation, element, and / or component, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0051] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It should be further understood that terms used herein shall be interpreted as having the same meaning as they have in the context of this description and the relevant technical field, and shall not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0052] This document describes embodiments with reference to schematic diagrams of embodiments of this disclosure. Therefore, the actual dimensions of the layers and elements may differ, and the shapes of the illustrations may vary due to manufacturing techniques and / or tolerances. For example, areas represented or described as squares or rectangles may have circular or curved features, and areas represented as straight lines may have some irregularities. Therefore, the areas shown in the figures are schematic, and their shapes are not intended to illustrate the precise shape of the device areas, nor are they intended to limit the scope of this disclosure. Furthermore, for illustrative purposes, the size of structures or areas may be exaggerated relative to other structures or areas; therefore, these structures or areas are provided to illustrate the general structure of the subject matter and may or may not be drawn to scale. Common elements between figures may be indicated herein by common element numbers and need not be redescribed subsequently.

[0053] This disclosure relates to solid-state lighting devices, and more specifically, to the arrangement of light-modifying materials for light-emitting devices such as light-emitting diodes (LEDs). LED devices may include light-modifying materials disposed around the peripheral sidewalls of an LED chip without the need for a support base or lead frame. The light-modifying material, with decreasing thickness, may be disposed along the peripheral sidewalls of the LED chip. In this regard, the exemplary LED devices disclosed herein may be configured with a footprint adjacent to the footprint of the LED chip within the LED device, while a certain amount of light-modifying material is disposed around the peripheral edge of the LED chip to reduce crosstalk. Therefore, such LED devices may be well-suited for applications where the LED device forms a closely spaced LED array. Manufacturing techniques are disclosed, including laminating a preform of the light-modifying material onto one or more surfaces of the LED chip.

[0054] LED chips typically include an active LED structure or region, which may have many different semiconductor layers arranged in different ways. The fabrication and operation of LEDs and their active structures are well known in the art and will only be briefly discussed herein. The layers of an active LED structure can be fabricated using known processes, with metal-organic chemical vapor deposition being a suitable process. The layers of an active LED structure may include many different layers and typically include an active layer sandwiched between n-type and p-type oppositely doped epitaxial layers, all of which are sequentially formed on a growth substrate. It is understood that an active LED structure may also include additional layers and elements, including but not limited to buffer layers, nucleation layers, superlattice structures, undoped layers, cladding layers, contact layers, current spreading layers, and light extraction layers and elements. The active layer may include a single quantum well, multiple quantum wells, a double heterostructure, or a superlattice structure.

[0055] Active LED structures can be made from various material systems, some of which are based on group III nitrides. Group III nitrides are semiconductor compounds formed between nitrogen (N) and periodic table group III elements (typically aluminum (Al), gallium (Ga), and indium (in)). Gallium nitride (GaN) is a common binary compound. Group III nitrides also include 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, the active layer, n-type layer, and p-type layer can include one or more layers of GaN, AlGaN, InGaN, and AlInGaN, either undoped or doped with Si or Mg based on group III nitride material systems. Other material systems include silicon carbide (SiC), organic semiconductor materials, and other group III-V systems such as gallium phosphide (GaP), gallium arsenide, and related compounds.

[0056] Active LED structures can be grown on a substrate that can include many materials, such as sapphire, SiC, aluminum nitride (AlN), and GaN. A suitable substrate is the 4H polytype of SiC, but other SiC polytypes, including 3C, 6H, and 15R polytypes, can also be used. SiC offers several advantages, such as a closer lattice match to group III nitrides compared to other substrates, resulting in high-quality group III nitride thin films. SiC also has high thermal conductivity, so the total output power of group III nitride devices on SiC is not limited by substrate heat dissipation. Sapphire is another common substrate for group III nitrides and also offers several advantages, including lower cost, established manufacturing processes, and good optical transmission properties.

[0057] Depending on the composition of the active layer and the n-type and p-type layers, different embodiments of the active LED structure can emit light of different wavelengths. In some embodiments, the active LED structure emits blue light with a peak wavelength range of approximately 430 nanometers (nm) to 480 nanometers. 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.

[0058] The LED chip may also be coated with one or more fluorescent materials (also referred to herein as phosphors), such as phosphors, such that at least some of the light from the LED chip is absorbed by one or more phosphors, and the emission is converted into one or more different wavelength spectra according to the characteristics of one or more phosphors. In this respect, at least one phosphor receives at least a portion of the light generated by the LED light source and can re-emit light with a different peak wavelength than the LED light source. The LED light source and one or more fluorescent materials may be selected so that their combined output produces light with one or more desired characteristics (e.g., color, color point, intensity, etc.). In some embodiments, the aggregate emission of the LED chip (optionally combined with one or more fluorescent materials) may be arranged to provide cool white, neutral white, or warm white light, for example, in a color temperature range of 2500K to 10000K. In some embodiments, fluorescent materials having cyan, green, amber, yellow, orange, and / or red peak wavelengths may be used. In some embodiments, the combined emission of the LED chip and one or more phosphors (e.g., phosphors) is generally a combination of white light. One or more phosphors may include yellow (e.g., YAG:Ce), green (e.g., LuAg:Ce), and red (e.g., Ca) light. i-x-y Sr x Eu y AlSiN3) emitting phosphors and their combinations.

[0059] The fluorescent materials described herein may be or include one or more of phosphors, scintillators, fluorescent inks, quantum dot materials, solar-emitting bands, etc. Fluorescent materials can be provided by any suitable means, such as direct coating on one or more surfaces of an LED, dispersion in an encapsulation material configured to cover one or more LEDs, and / or coating on one or more optical or support elements (e.g., by powder coating, inkjet printing, etc.). In some embodiments, the fluorescent material may be down-conversion or up-conversion, and combinations of down-conversion and up-conversion materials may be provided. In some embodiments, multiple different (e.g., different compositions) fluorescent materials may be arranged to produce different peak wavelengths to receive emission from one or more LED chips. One or more fluorescent materials may be disposed on one or more portions of an LED chip in various configurations. In some embodiments, one or more surfaces of an LED chip may be conformally coated with one or more fluorescent materials, while other surfaces of such an LED chip may be without fluorescent material. In some embodiments, the top surface of an LED chip may include fluorescent material, while one or more sides of the LED chip may be without fluorescent material. In some embodiments, all or substantially all outer surfaces of an LED chip (e.g., except for contact-defined or mounting surfaces) are coated or otherwise covered with one or more fluorescent materials. In some embodiments, one or more fluorescent materials may be arranged substantially uniformly on one or more surfaces of the LED chip. In other embodiments, one or more fluorescent materials may be arranged non-uniformly relative to the composition, concentration, and thickness of one or more materials on or above one or more surfaces of the LED chip. In some embodiments, the loading percentage of one or more fluorescent materials may vary on or between one or more outer surfaces of the LED chip. In some embodiments, one or more fluorescent materials may be patterned on portions of one or more surfaces of the LED chip to include one or more stripes, dots, curves, or polygons. In some embodiments, multiple fluorescent materials may be arranged in different discrete regions or discrete layers on or above the LED chip.

[0060] In some embodiments, one or more fluorescent materials may be disposed as at least a portion of the wavelength conversion element. The wavelength conversion element may include a support element, such as a cover, and one or more fluorescent materials provided by any suitable means, such as by coating a surface of the cover or by incorporation within the cover. As used herein, the term "cover" refers to an element that may include fluorescent material and is placed on or over an LED chip. The term "cover" is used in part herein to avoid confusion with other substrates that may be part of a semiconductor light-emitting device, such as a growth or carrier substrate for an LED chip or a base for an LED package. The term "cover" is not intended to limit the orientation, location, and / or composition of the structure described herein. In some embodiments, the cover may be composed of a transparent, translucent, or light-transmitting material, such as sapphire, SiC, silicon, and / or glass (e.g., borosilicates and / or fused silica). As described in U.S. Patent Application Publication No. 2019 / 0326484, entitled "Semiconductor Light Emitting Devices Including Superstrates With Patterned Surfaces," which is incorporated herein by reference. The cover may also be configured as described in commonly assigned U.S. Patent Application Publication No. 2018 / 0033924, which is also incorporated herein by reference. The cover may be formed from a bulk substrate, which may be selectively patterned and then separated. In some embodiments, the cover may be patterned by an etching process (e.g., wet or dry etching). In some embodiments, the cover may be patterned by other means of surface modification (e.g., by laser or sawing). In some embodiments, the cover may be thinned before or after patterning. In some embodiments, the cover may include a generally planar upper surface corresponding to the light-emitting area of ​​the LED package.

[0061] One or more fluorescent materials can be disposed on a cover by, for example, spraying and / or otherwise coating the cover with fluorescent materials. Wavelength conversion elements can be attached to one or more LED chips using, for example, a transparent adhesive layer. In some embodiments, the transparent adhesive layer may comprise a silicone resin with a refractive index in the range of about 1.3 to about 1.6, which is less than the refractive index of the LED chip on which the wavelength conversion element is placed. In other embodiments, the wavelength conversion element may comprise an alternative configuration, such as a phosphor or ceramic phosphor plate arrangement in glass. A phosphor or ceramic phosphor plate arrangement in glass can 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 conversion elements.

[0062] Light emitted from the active layer or region of an LED chip typically exhibits a Lambertian emission mode. For directional applications, internal mirrors or external reflective surfaces can be used to redirect as much light as possible to the desired emission direction. Internal mirrors can comprise a single layer or multiple layers. Some multilayer mirrors include a metallic reflective layer and a dielectric reflective layer, wherein the dielectric reflective layer is disposed between the metallic reflective layer and multiple semiconductor layers. A passivation layer is disposed between the metallic reflective layer and first and second electrical contacts, wherein the first electrical contact is disposed in conductive communication with a first semiconductor layer, and the second electrical contact is disposed in conductive communication with a second semiconductor layer. For single-layer or multilayer mirrors comprising surfaces with reflectivity below 100%, some light may be absorbed by the mirror. Furthermore, light redirected by the active LED structure may be absorbed by other layers or elements within the LED chip.

[0063] As used herein, a layer or region of a light-emitting device can be considered "transparent" when at least 80% of the emitted radiation striking a light-emitting device layer or region passes through that layer or region. Furthermore, as used herein, an LED layer or region is considered "reflective" or contains a "mirror" or "reflector" when at least 80% of the emitted radiation striking an LED layer or LED region 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 can include invisible light. For example, in the context of GaN-based blue and / or green LEDs, silver (Ag) can be considered a reflective material (e.g., at least 80% reflective). In the case of ultraviolet (UV) LEDs, appropriate materials can be selected to provide the desired, in some embodiments, high reflectivity and / or the desired, in some embodiments, low absorptivity. In some embodiments, a "transparent" material can be configured to transmit at least 50% of the emitted radiation at the desired wavelength.

[0064] This disclosure can be used for LED chips having various geometries, such as vertical or horizontal geometries. In some embodiments, vertical or horizontal geometry LED chips can be configured as specified in commonly assigned U.S. Patent No. 9,461,201, which is incorporated herein by reference. Vertical geometry LED chips typically include anode and cathode connections on opposite sides or faces of the LED chip. Horizontal geometry LED chips typically include anode and cathode connections on the same side of the LED chip, which is opposite a substrate (such as a growth substrate). In some embodiments, horizontal geometry LED chips can be mounted on a base of an LED package such that the anode and cathode connections are located on the face of the LED chip opposite the base. In this configuration, wire bonding can be used to provide electrical connections to the anode and cathode connections. In other embodiments, horizontal geometry LED chips can be flip chips mounted on the surface of a base of an LED package such that the anode and cathode connections are located on the surface of an active LED structure adjacent to the base. In this configuration, traces or patterns can be formed on the base to provide electrical connections to the anode and cathode connections of the LED chip. In a flip-chip configuration, an active LED structure is disposed between a substrate of the LED chip and a base of the LED package. Therefore, light emitted from the active LED structure can pass through the substrate in a desired emission direction. In some embodiments, the flip-chip LED chip can be configured as described in commonly assigned U.S. Patent Application Publication No. 2017 / 0098746, which is incorporated herein by reference. In other embodiments, the active LED structure can be bonded to a carrier base, and the growth substrate can be removed, allowing light to exit the active LED structure without passing through the growth substrate. In some embodiments, the LED package can be configured as specified in the following commonly assigned U.S. patents and publications, which are incorporated herein by reference: U.S. Patent Nos. 8,866,169; 9,070,850; 9,887,327; and 10,468,565.

[0065] The aspects disclosed herein may be useful for LED modules, systems, or stationary devices, including closely spaced LED emitters or devices capable of providing overall combined emission as well as numerous variable, selectable, or adjustable emission characteristics through individual control of the LED devices. In this way, the LED devices are placed as close to each other as possible so that they may appear as a single emission area when all devices are electrically activated, and some or several groups of closely spaced LED devices may be individually electrically activated or deactivated when different emission characteristics are required. In such applications, size and spacing limitations may prevent the use of individually packaged LEDs. Conventional LED packages typically consist of an LED chip mounted on a large base and a package surrounding the LED chip on the base, resulting in a larger footprint for the LED package relative to the LED chip. Furthermore, conventional LED packages may also include multiple LED chips arranged on a common substrate (e.g., a ceramic panel) or leadframe package. However, this also contributes to an increased package footprint to accommodate the common substrate or leadframe. This increased footprint may be undesirable for manufacturers looking to build pixelated lighting systems, such as those for adaptive automotive headlights or display applications.

[0066] According to the aspects disclosed herein, LED devices have a reduced footprint, allowing for the assembly of closely spaced arrays of LED devices on a common support (e.g., a printed circuit board (PCB)). The LED devices disclosed herein can be manufactured without conventional bases and lead frames that contribute to increased footprint. In some aspects, LED devices capable of being attached to external electrical connections (such as connections on a PCB) without using conventional bases and lead frames can be referred to as chip-scale packages (CSPs). In this regard, a CSP may include one or more components, such as phosphors, sealants, light-changing materials, lenses, and electrical contacts, which house one or more LED chips without conventional bases or lead frames. For close-pitch applications, LED devices (e.g., CSPs) can also be configured to avoid interaction or crosstalk that may be caused by emissions overflowing from adjacent LED devices. In this regard, the LED devices disclosed herein can be configured with a footprint close to the footprint of the LED chips within the LED device, while a certain amount of light-changing material is disposed around the peripheral edges of the LED chips to reduce crosstalk.

[0067] As used herein, light-modifying materials can include a variety of different materials, including light-reflecting materials that reflect or redirect light, light-absorbing materials that absorb light, and materials used as thixotropic agents. As used herein, the term "light-reflecting" refers to a material or particle that reflects, refracts, or otherwise redirects light. For light-reflecting materials, light-modifying materials can include at least one of fused silica, fumed silica, titanium dioxide (TiO2), or metal particles suspended in a binder (such as silicone or epoxy resin). For light-absorbing materials, light-modifying materials can include at least one of carbon, silicon, and metal particles suspended in a binder (such as silicone or epoxy resin). Light-reflecting and light-absorbing materials can include nanoparticles. In some embodiments, light-modifying materials can be generally white to reflect and redirect light. In other embodiments, light-modifying materials can be generally opaque or black to absorb light and increase contrast.

[0068] In some embodiments, the light-changing material includes a light-reflecting material and a light-absorbing material suspended in an adhesive. The weight ratio of the light-reflecting material to the adhesive can range from about 1:1 to about 2:1. The weight ratio of the light-absorbing material to the adhesive can range from about 1:400 to about 1:10. In some embodiments, the total weight of the light-changing material includes any combination of the adhesive, the light-reflecting material, and the light-absorbing material. In some embodiments, the adhesive can include a weight percentage ranging from about 10% to about 90% of the total weight of the light-changing material. The light-reflecting material can include a weight percentage ranging from about 10% to about 90% of the total weight of the light-changing material. The light-absorbing material can include a weight percentage ranging from about 0% to about 15% of the total weight of the light-changing material.

[0069] In a further embodiment, the light-absorbing material may include a weight percentage ranging from about 0% to about 15% of the total weight of the light-changing material. In a further embodiment, the adhesive may include a weight percentage ranging from about 25% to about 70% of the total weight of the light-changing material. The light-reflecting material may include a weight percentage ranging from about 25% to about 70% of the total weight of the light-changing material. The light-absorbing material may include a weight percentage ranging from about 0% to about 5% of the total weight of the light-changing material. In a further embodiment, the light-absorbing material may include a weight percentage ranging from about 0% to about 5% of the total weight of the light-changing material.

[0070] In some aspects, light-changing materials can be incorporated into preforms or layers comprising light-changing particles suspended in an adhesive. For example, light-changing particles can be suspended in an incompletely cured silicone adhesive to provide a preform of light-changing material. The desired thickness or height of the preform can be provided by moving a scraper or similar tool across the sheet. The preform can then be positioned on and subsequently formed around an LED chip and / or a wavelength conversion element on the LED chip. For example, the preform can be laminated around the LED chip and / or wavelength conversion element and then fully cured in place. One or more portions of the preform can then be removed from the primary emitting surface of the LED chip and / or wavelength conversion element. In this way, light-changing materials can be formed along the peripheral edges or sidewalls of the LED chip and wavelength conversion element to a thickness previously infeasible in conventional dispensing techniques commonly used to form light-changing materials. Furthermore, light-changing materials can be incorporated without conventional bases or lead frames as support for conventional dispensing and / or molding techniques. In this respect, LED devices incorporating light-changing materials can offer a reduced footprint suitable for closely spaced LED arrangements.

[0071] In certain applications, the LED devices disclosed herein may be well-suited for closely spaced array applications, such as automotive lighting, general lighting, and lighting displays. For exterior automotive lighting, multiple LED devices can be arranged under a common lens or optics to provide a single, integral emission or multiple emissions that can vary between different emission characteristics. Changing emission characteristics can include switching between high and low beam emission, adaptively changing emission, and adjusting the correlated color temperature (CCT) to correspond to daytime and nighttime operating conditions. In general lighting applications, the LED devices disclosed herein can be configured to provide modules, systems, and fixtures capable of providing one or more different emission colors or CCT values, such as one or more warm whites (e.g., 2700 Kelvin (K) to 3000 K), neutral whites (e.g., 3500 K to 4500 K), and cool whites (5000 K to 6500 K). For horticultural lighting applications, the LED devices disclosed herein can be arranged to provide modules, systems, and fixtures capable of varying emission characteristics for different growing conditions of different crops.

[0072] Figure 1A This is a cross-sectional view of an LED device 10 according to the aspects disclosed herein. The LED device 10 includes an LED chip 12, and the LED device 10 does not have the base and / or lead frame typically found in conventional LED packages. In this respect, the LED device 10 may be referred to as a CSP. Although Figure 1AA single LED chip 12 is shown, but the LED device 10 may include multiple LED chips 12 without departing from the principles disclosed herein. The LED chip 12 may include a top surface 12a, a bottom surface 12b, and peripheral sidewalls 12c that bind the top surface 12a and the bottom surface 12b together. For example, for a square or rectangular area of ​​the top surface 12a and the bottom surface 12b, the LED chip 12 may include four peripheral sidewalls 12c. In some embodiments, the LED device 10 may include a wavelength conversion element 14 comprising a cover 16 and a phosphor material 18 disposed thereon. The cover 16 may comprise a material that is transparent to light emitted by the LED chip and to light converted by the phosphor material 18. The cover 16 may also be textured to improve light extraction or contain materials such as phosphors or scattering particles. The phosphor material 18 may include any material as described above, including one or more phosphors that provide the same or different emission characteristics. In some embodiments, the cover 16 and the phosphor material 18 may be attached to the LED chip 12 using, for example, a transparent adhesive layer (such as silicone). In some embodiments, fluorescent material 18 is formed between the cover 16 and the LED chip 12, thereby protecting fluorescent material 18 from environmental exposure.

[0073] like Figure 1AAs further explained below, a light-changing material 20 is disposed around the peripheral sidewall 12c of the LED chip 12. The light-changing material 20 can also be disposed around the peripheral sidewall 14c of the wavelength conversion element 14. As described above, and will be further described in detail below, the light-changing material 20 can be formed by a lamination process, having a reduced thickness 20t measured laterally from the peripheral sidewall 12c of the LED chip 12 or the peripheral side surface 14c of the wavelength conversion element 14. In some embodiments, the thickness 20t of the light-changing material 20 is in the range of 15 micrometers (μm) to 100 μm, or in the range of 15 μm to 60 μm, or in the range of 15 μm to 50 μm, or in the range of 20 μm to 50 μm. This range of thickness 20t can be configured differently for different sizes of the LED chip 12. For example, in a particular embodiment, the height of the LED chip 12, measured from the top surface 12a to the bottom surface 12b, can range from 100 μm to 150 μm. In this regard, the light-changing material 20 can be configured with a thickness of 20t, ranging from 40 μm to 60 μm. Due to the manufacturing process described below, a higher thickness 20t value for the light-changing material 20, if too close to the height of the LED chip 12, may compromise the proper uniformity of the light-changing material 20 around the LED chip 12. Furthermore, this range of thicknesses 20t can be configured differently depending on the desired spacing between the LED device 10 and other LED devices, with lower thicknesses 20t values ​​corresponding to lower achievable spacing. In some embodiments, a thickness of 20t is provided around all peripheral sidewalls 12c of the LED chip 12 and / or all peripheral sides 14c of the wavelength conversion element 14, thereby providing the LED device with an overall footprint only nominally larger than the LED chip 12 itself.

[0074] like Figure 1AAs shown, the light-changing material 20 can be formed in a manner that allows it to conform to the peripheral sidewall 12c of the LED chip 12 and the peripheral sidewall 14c of the wavelength conversion element 14. In this respect, the thickness 20t of the light-changing material 20 can be the same for both the peripheral sidewall 12c of the LED chip 12 and the peripheral sidewall 14c of the wavelength conversion element 14, and there is a curved transition between them. Furthermore, the top surface 20a of the light-changing material 20 can be arranged to be coplanar or substantially coplanar with the top surface 14a of the wavelength conversion element 14. In this way, the top surface 14a of the wavelength conversion element 14 forms the main light-emitting surface of the LED device 10. The LED device 10 may also include cathode contacts 22 and anode contacts 24, which are disposed on the bottom surface 12b of the LED chip 12 in a flip-chip arrangement. The bottom surface 20b of the light-changing material 20 can be coplanar with the bottom surface 12b of the LED chip 12, or coplanar with the bottom surfaces of the cathode contacts 22 and the anode contacts 24. As shown in the figure, the LED device 10 does not have a conventional base or lead frame, but still includes light-changing material 20 and wavelength conversion element 14. With this arrangement, the cathode contact 22 and anode contact 24 can be configured to directly mount external electrical connections, such as traces on a PCB.

[0075] Figure 1B yes Figure 1A A top view of the LED device 10. As shown, light-changing material 20 is arranged around the outer periphery of wavelength conversion element 14. From the top view, fluorescent material 18 can be seen through the covering. Figure 1A (16 in the text). It is worth noting that, due to the nature of the lamination process, the light conversion material 20 forms a reduced thickness 20t, with the rounded corners 20' aligned with the peripheral edge corners 14' of the wavelength conversion element 14. In contrast, in conventional LED packages, the lines of light conversion material are typically distributed on a common substrate between the LED chips, and then a saw blade cuts along the light conversion material lines to create a thicker light conversion material with square corners formed by the sawing.

[0076] Figure 1C yes Figure 1A A bottom view of the LED device 10. As shown, light-changing material 20 is arranged around the outer periphery of the LED chip 12, with rounded corners 20' aligned with the peripheral sidewall corners 12' of the LED chip 12. From the bottom view, cathode contacts 22 and anode contacts 24 are accessible from the bottom surface 12b of the LED chip 12 and are configured to provide external electrical connections. In some embodiments, the bottom surface 12b of the LED chip 12 does not contain light-changing material 20. In contrast, conventionally dispersed light-changing materials may tend to gradually weaken (wick, taper) along the bottom surface 12b, which could lead to debonding failure after installation.

[0077] Figures 2A to 2G yes Figure 1A A cross-sectional view of LED equipment 10 during a continuous manufacturing process. (For ease of explanation) Figures 2A to 2G A single LED device 10 is shown, but it can be understood that, in reality, according to Figures 2A to 2G It can simultaneously generate multiple LED devices 10. Figure 2A In this configuration, the LED chip 12 is attached to a temporary carrier 23, such that the cathode contact 22 and the anode contact 24 are arranged between the LED chip 12 and the temporary carrier 23. In some embodiments, the temporary carrier 23 comprises a flexible tape on which multiple LED chips 12 can be disposed. Figure 2B In the figure, wavelength conversion element 14 is attached to the top surface 12a of LED chip 12. As shown, wavelength conversion element 14 may include a lateral dimension larger than the lateral dimension of LED chip 12, thereby increasing alignment tolerance.

[0078] exist Figure 2C In this process, a preform of light-changing material 20 is placed above the LED chip 12. Figure 2D In this configuration, a preform of light-modifying material 20 is positioned on the LED chip 12 and the wavelength conversion element 14. As previously described, the preform of light-modifying material 20 may comprise light-modifying particles or materials provided in a partially cured adhesive (such as partially cured silicone). In this respect, the preform of light-modifying material 20 is single and flexible to conform to the LED chip 12 and the wavelength conversion element 14. After the preform is positioned, the LED device 10 may be placed in a chamber with a vacuum pressure below atmospheric pressure and lowered onto a heat source 25, such as a heating plate, to facilitate the lamination of the light-modifying material 20. Figure 2E In this process, a light-modifying material 20 is conformally laminated around the outer peripheral sidewall 14c of the wavelength conversion element 14 and the outer peripheral sidewall 12c of the LED chip 12. In some embodiments, the arrangement of the cathode contacts 22 and anode contacts 24 on the temporary carrier 23 can prevent the light-modifying material 20 from forming on the bottom surface 12b of the LED chip 12. In this respect, a portion of the light-modifying material 20 can extend laterally on the temporary carrier 23. When multiple LED devices 10 are formed simultaneously on the temporary carrier 23, the light-modifying material 20 can be continuously laminated on all of the multiple LED devices 10. As shown, the light-modifying material 20 is also formed on or above the top surface 12a of the LED chip 12. After the lamination process, the LED device 10 can be placed in an oven or the like to allow the light-modifying material 20 to fully cure in place.

[0079] exist Figure 2FIn this process, a portion of the light-converting material 20 located on the top surface 12a of the LED chip 12 and the top surface 14a of the wavelength conversion element 14 is removed to allow the LED device 10 to emit light in a desired direction. In some embodiments, a polishing process can be used such that the top surface 20a of the light-converting material 20 is coplanar with the top surface 14a of the wavelength conversion element 14. In other embodiments, etching or sandblasting processes can be used. Figure 2G As shown, the LED device 10 is removed or detached from the temporary carrier 23 in order to achieve the above-described Figure 1A The light-changing material 20 is configured as described above. In some embodiments, a sawing process may be applied to the temporary carrier 23 to separate the LED device 10 and a portion of the light-changing material 20 from other LED devices disposed near the temporary carrier 23. As shown, all surfaces of the fluorescent material 18 can be covered by the covering 16 and the light-changing material 20, thereby reducing the exposure of the fluorescent material 18 to the environment and correspondingly reducing the degradation of the fluorescent material 18.

[0080] According to the aspects disclosed herein, various combinations of LED devices can, as described above, arrange light-changing materials around the peripheral sidewalls of the LED chip. Different configurations of the wavelength conversion elements can be provided. In various embodiments, the LED device can also be equipped with lenses of various shapes, including hemispherical or dome-shaped, ellipsoidal, bullet-shaped, flat, hexagonal, cubic, and square. In some embodiments, suitable lens shapes include curved surfaces and flat surfaces, such as a hemispherical top with flat sides. The lens can also be textured to improve light extraction or contain materials such as phosphors or scattering particles. As described below, Figures 3 to 22 This includes various configurations of LED devices, which have features according to Figures 1 to 14 above. Figure 2G The embodiments provide and form light-changing materials.

[0081] Figure 3 It is similar to Figure 1A The diagram shows a cross-sectional view of LED device 26 within LED device 10, where the lateral dimension of wavelength conversion element 14 is smaller than that of LED chip 12. In this respect, light-changing material 20 can be conformally mounted on the peripheral sidewall 12c of LED chip and the peripheral sidewall 14c of wavelength conversion element 14. By arranging wavelength conversion element 14 to be smaller than the latter size of LED chip 12, a portion of light-changing material 20 can be disposed on the top surface 12a of LED chip 12, thereby providing a smaller light-emitting surface for LED device 26, which may be useful for applications requiring narrower emission.

[0082] Figure 4 It is similar to Figure 1AThe diagram shows a cross-sectional view of LED device 28 within LED device 10, where the lateral dimension of wavelength conversion element 14 is the same as that of LED chip 12. In this respect, light-changing material 20 can be conformally fitted on the peripheral sidewall 12c of LED chip 12 and the peripheral sidewall 14c of wavelength conversion element 14, without curved surfaces or profiles, whereas curved surfaces or profiles would be formed if the peripheral sidewall 12c of LED chip 12 were offset from the peripheral sidewall 14c of wavelength conversion element 14c. In this way, LED device 28 can be directly adjacent to another similarly configured LED device, reducing the gap between them.

[0083] Figure 5 It is similar to Figure 4 The diagram shows a cross-sectional view of LED device 30 within LED device 28, but with the phosphor material 18 and the cover 16 of the wavelength conversion element 14 positioned opposite each other. In this respect, the cover 16 is arranged on the top surface 12a of the LED chip 12, such that the cover 16 is positioned between the phosphor material 18 and the LED chip 12. This arrangement provides separation between the phosphor material 18 and the LED chip 12, which can reduce heating of the phosphor material 18 when the LED chip 12 is electrically activated. By ensuring that the phosphor material 18 is not completely covered by the cover 16 and the light-changing material 20, the LED device can be suitable for applications requiring reduced environmental exposure or for applications requiring additional housings or encapsulations to reduce exposure between the surrounding environment and the phosphor material 18.

[0084] Figure 6 It is similar to Figure 5 The diagram shows a cross-sectional view of LED device 32 within LED device 30, but in this view, fluorescent material 18 is disposed throughout the wavelength conversion element 14. In this respect, the fluorescent material 18 can be embedded in a covering. Figure 5 (16) Wavelength conversion element 14 may include one or more of the following: a ceramic phosphor plate, a phosphor in glass, and a phosphor embedded in a silicone resin layer. As previously described, the arrangement of phosphor in glass or ceramic phosphor plate can be formed by mixing phosphor particles with glass frit or ceramic material, pressing the mixture into a planar shape, and firing or sintering the mixture to form a hardened structure, which can be cut or separated into individual wavelength conversion elements 14. As previously described, light-changing material 20 may be formed around such wavelength conversion element 14.

[0085] Figure 7 It is similar to Figure 5A cross-sectional view of LED device 34 in LED device 30 is shown, but in which LED device 34 does not contain phosphor material 18. In this regard, a lens 36 can be disposed on LED chip 12, which does not convert the wavelength of the light generated by LED chip 12. Lens 36 may comprise a light-transmitting and / or transparent material similar to the cover described above. In other embodiments, lens 36 may comprise silicone and / or glass. As shown, lens 36 forms a planar lens above LED chip 12. Lens 36 may also be textured to improve light extraction or contain materials such as phosphors or scattering particles. Light-changing material 20 may be formed around lens 36 in a similar manner to that described previously, for forming light-changing material 20 around wavelength conversion element. Figure 5 (14 in the text). In this respect, LED device 34 can be configured to emit a single color or monochromatic light.

[0086] Figure 8 It is similar to Figure 4 The diagram shows a cross-sectional view of LED device 28 and LED device 38, but without light-changing material 20 around the peripheral sidewall 14c of wavelength conversion element 14. In this respect, wavelength conversion element 14 can be arranged in LED chip 12 after light-changing material 20 is formed around the peripheral sidewall 12c of LED chip 12. As shown, phosphor material 18 can be arranged on the top surface 20a of light-changing material 20. In such an arrangement, a portion of the light-changing material 20 temporarily formed on the top surface 12a of LED chip 12 can be removed before placing wavelength conversion element 14. In some embodiments, the top surface 20a of light-changing material 20 is coplanar with the top surface 12a of LED chip 12. As shown, in some embodiments, wavelength conversion element 14 can be arranged on the entire top surface 20a of light-changing material 20. In other embodiments, wavelength conversion element 14 can be arranged partially on the top surface 20a of light-changing material 20. As configured, the LED device 38 can be arranged such that the light emission generated by the LED chip 12 can be directed to the wavelength conversion element 14 via the light-changing material 20. Since the peripheral side 14c of the wavelength conversion element 14 is not surrounded by the light-changing material 20, the overall emission of the LED device 38 may have a wider far-field emission mode.

[0087] Figure 9 It is similar to Figure 8 A cross-sectional view of LED device 40 in LED device 38, but in which the order of phosphor material 18 and cover 16 of wavelength conversion element 14 is reversed. In this respect, cover 16 is arranged on the top surface 12a of LED chip 12, such that cover 16 is arranged between phosphor material 18 and LED chip 12. As previously described... Figure 5As described in LED device 30, this arrangement provides separation of the fluorescent material 18 from the LED chip 12, which can reduce heating of the fluorescent material 18 when the LED chip 12 is electrically activated. Figure 9 As shown, the cover 16 is arranged on the top surface 20a of the light-changing material 20.

[0088] Figure 10 It is similar to Figure 6 The diagram shows a cross-sectional view of LED device 32 and LED device 42, but in this view, wavelength conversion element 14 is also located on the top surface 20a of light conversion material 20. In this respect, fluorescent material 18 can be embedded in the covering. Figure 5 (16) Wavelength conversion element 14 may include one or more of the following: a ceramic phosphor plate, a phosphor in glass, and a phosphor embedded in a silicone resin layer. As previously described, the arrangement of phosphor in glass or ceramic phosphor plate can be formed by mixing phosphor particles with glass frit or ceramic material, pressing the mixture into a planar shape, and firing or sintering the mixture to form a hardened structure, which can be cut or separated into individual wavelength conversion elements 14. Because the peripheral side 14c of wavelength conversion element 14 is not surrounded by light-changing material 20, the overall emission of LED device 42 may have a wider far-field emission mode. As shown, in some embodiments, wavelength conversion element 14 may be arranged on the entire top surface 20a of light-changing material 20. In other embodiments, wavelength conversion element 14 may be arranged partially on the top surface 20a of light-changing material 20.

[0089] Figure 11 It is similar to Figure 7 The diagram shows a cross-sectional view of LED device 44, specifically LED device 34, where lens 36 is disposed on the top surface 12a of LED chip 12 and the top surface 20a of light-changing material 20. As previously described, lens 36 may comprise a light-transmitting and / or transparent material similar to the previously described cover 16. In other embodiments, lens 36 may comprise silicone and / or glass. Lens 36 may also be textured to improve light extraction or contain materials such as phosphors or scattering particles. In some embodiments, lens 36 may be disposed over the entire top surface 20a of light-changing material 20. In other embodiments, lens 36 may be disposed partially over the top surface 20a of light-changing material 20. As shown, lens 36 forms a planar lens above LED chip 12. In this respect, LED device 44 may be configured to emit a single color or monochromatic light.

[0090] Figure 12 It is similar to Figure 11The diagram shows a cross-sectional view of LED device 46 within LED device 44, but in which lens 36 forms a curved surface 36' above LED chip 12. In some embodiments, lens 36 is typically hemispherical or dome-shaped, although other shapes are also possible. Therefore, the increased amount of light reaching the surface 36' of lens 36 may pass through lens 36 on its first pass without being redirected back to LED chip 12. Furthermore, lens 36 can be used to guide light emission in a desired emission mode. Lens 36 can be made of many different materials, including silicone, plastic, epoxy, or glass, or suitable materials compatible with molding processes. Silicone is suitable for molding and provides acceptable optical transmission characteristics for the light emitted by LED chip 12. In some embodiments, lens 36 can be molded into many different shapes, depending on the desired light output shape. Besides hemispherical or dome shapes, other shapes can include ellipsoidal bullet shapes, planar shapes, hexagonal shapes, cubes, and squares. In some embodiments, suitable shapes include curved surfaces and planar surfaces, such as a hemispherical top with planar sides. Lens 36 may also be textured to improve light extraction or contain materials such as phosphors or scattering particles. As shown, fluorescent material 18 is disposed between lens 36 and LED chip 12, and light-modifying material 20 is disposed peripherally around fluorescent material 18. Therefore, light-modifying material 20 can be configured to direct light emitted from LED chip 12 and / or light converted by fluorescent material 18 toward lens 36. In some embodiments, fluorescent material 18 includes one or more of a ceramic phosphor plate, a phosphor in glass, and a phosphor embedded in a silicone layer.

[0091] Figure 13 It is similar to Figure 12 The diagram shows a cross-sectional view of LED device 48 within LED device 46, but with a phosphor material 18 disposed on surface 36' of lens 36. In this respect, the phosphor material 18 is spaced apart from LED chip 12, thereby reducing the heat generated by LED chip 12 reaching the phosphor material 18. In some embodiments, the phosphor material 18 can be formed on lens 36 by a spraying process, wherein phosphor particles mixed in silicone resin are sprayed along surface 36' of lens 36. In other embodiments, the phosphor material 18 can be molded onto lens 36, or the shape of the phosphor material 18 can be compatible with surface 36' of lens 36. As in other embodiments, light-changing material 20 can be arranged to direct light toward lens 36.

[0092] Figure 14 It is similar to Figure 13A cross-sectional view of LED device 50 in LED device 48 is shown, but in which fluorescent material 18 is embedded in lens 36. In this embodiment, fluorescent material 18 can be mixed with the material of lens 36 before the shape of lens 36 is formed. Lens 36 having fluorescent material 18 can be molded on LED chip 12, or lens 36 having fluorescent material 18 can be provided as a preformed structure attached to LED chip 12. As in other embodiments, light-changing material 20 can be arranged to direct light toward lens 36.

[0093] Figure 15 It is similar to Figure 14 The diagram shows a cross-sectional view of LED device 52 within LED device 50, but without the fluorescent material 18 present in lens 36. In this respect, LED device 52 can be configured to emit a single color or monochromatic light. As in other embodiments, the light-changing material 20 can be arranged to direct light toward lens 36.

[0094] Figure 16 It is similar to Figure 15 A cross-sectional view of LED device 54 in LED device 52, but in which fluorescent material 18 is located between LED chip 12 and lens 36. LED device 54 is also similar to Figure 12 The LED device 54 includes an LED chip 12, a light-changing material 20, and a lens 36. In this respect, the fluorescent material 18 is completely surrounded within the LED device 54 by the LED chip 12, the light-changing material 20, and the lens 36. As in other embodiments, this reduces the potential degradation of the fluorescent material 18 when exposed to external environmental conditions.

[0095] Figure 17 It is similar to Figure 16 The diagram shows a cross-sectional view of LED device 56 within LED device 54, but in this view, fluorescent material 18 is disposed on the surface 36' of lens 36. LED device 56 is also similar to... Figure 13 The LED device 48 is included, but a lens 36 is also disposed on the top surface 20a of the light-changing material 20. As in other embodiments, this provides a spacing relationship with the LED chip 12, thereby reducing the heat generated from the LED chip 12 that reaches the phosphor material 18.

[0096] Figure 18 It is similar to Figure 14The figure shows a cross-sectional view of LED device 58 of LED device 50, but in this view, a lens 36 is also disposed on the top surface 20a of light-changing material 20. As previously described, fluorescent material 18 can be mixed with the material of lens 36 before the shape of lens 36 is formed, and the light-changing material 20 can be arranged to direct light toward lens 36 and embed the fluorescent material 18 within lens 36. As shown, in some embodiments, lens 36 can be disposed on the entire top surface 20a of light-changing material 20a. In other embodiments, lens 36 can be disposed partially on the top surface 20a of light-changing material 20.

[0097] Figure 19 It is similar to Figure 15 The figure shows a cross-sectional view of LED device 60 of LED device 52, but in this view, a lens 36 is also disposed on the top surface 20a of light-changing material 20. In this respect, LED device 60 can be configured to emit a single color or monochromatic light. As in other embodiments, light-changing material 20 can be arranged to direct light toward lens 36. As shown, in some embodiments, lens 36 can be disposed on the entire top surface 20a of light-changing material 20a. In other embodiments, lens 36 can be disposed on a portion of the top surface 20a of light-changing material 20.

[0098] Figure 20 It is similar to Figure 4 A cross-sectional view of LED device 62 in LED device 28, but in which the light-changing material 20 further includes an extension 20 extending from the sidewall 12c of LED chip 12. Figure 2E and Figure 2F As shown, when light changes the material 20 around the temporary carrier ( Figure 2E When the LED chip 12 is laminated on 23), an extension 20 of the light-changing material can be formed. Figure 2G Unlike the LED device 10 shown, the LED device 62 can be separated at a laterally spaced position farther from the LED chip 12. Separation and removal of the temporary carrier ( Figure 2EFollowing step 23), an extension 20” of the light-changing material 20 can be formed. Therefore, the extension 20” can provide further protection and encapsulation along the base of the LED chip 12. In various embodiments, the bottom surface of the extension 20” can be coplanar with the bottom surface 12b of the LED chip 12, or with the bottom surfaces of the cathode contact 22 and the anode contact 24. The extension 20” can protrude from other portions of the light-changing material 20 on the peripheral sidewall 12c of the LED chip 12. In some embodiments, the extension 20” can be formed in an L-shape in cross-section. When the LED device 62 is mounted to an external component (such as a PCB), the extension 20” can be configured to extend laterally around the LED device 62 and extend on the surface of the external component adjacent to the mounting surface of the LED chip 12. In this respect, the extension 20” can be configured to provide additional encapsulation for the portion of the external component on which the LED device 62 is mounted.

[0099] Figure 21 It is similar to Figure 4 The diagram shows a cross-sectional view of LED device 64 within LED device 28, but in which light-modifying material 20 includes light-absorbing particles for enhancing contrast. In some embodiments, light-modifying material 20 includes generally opaque or black particles for absorbing light. For example, light-modifying material 20 may include black carbon particles (also known as carbon black) within a binder (such as silicone). In some embodiments, light-modifying material 20 may include one or more particles comprising materials such as Si that have a partially light-absorbing color (e.g., brown or other non-white and non-black). Thus, the partially light-absorbing material can have a higher refractive index than black particles to improve light refraction, while also including a light-absorbing color such as brown. Brown or other non-black or non-white colors can also provide a narrower absorption spectrum than black particles. In this respect, non-black or non-white light-absorbing particles can provide some light absorption properties to increase contrast, while also providing improved brightness, compared to black light-absorbing particles.

[0100] Figure 22 It is similar to Figure 21 The diagram shows a cross-sectional view of LED device 66 within LED device 64, but in which the light-modifying material 20 comprises light-absorbing particles and light-reflecting particles. In this respect, the light-modifying material 20 may comprise one or more combinations of white particles, black particles, and non-white and non-black particles. The mixture or ratio of light-absorbing and light-reflecting particles can be customized to provide different brightness and contrast characteristics for LED device 66 in different applications.

[0101] The LED devices disclosed herein, featuring thin edges formed by light-changing materials, are likely well-suited for a variety of applications requiring CSP (Concentrated Space Scale) or low-footprint devices. Such applications include many different types of LED arrays where LED emitters are close to each other, including display applications or various lighting applications such as automotive headlights or general lighting fixtures. In addition to LED array applications, the LED devices disclosed herein can also be used as single light sources with small footprints and small luminous surfaces, providing high candlelight or lumen output, such as in LED flashlights or strobe applications.

[0102] In some embodiments, any of the foregoing aspects and / or the various individual aspects and features described herein may be combined to obtain additional advantages. Unless otherwise stated herein, any of the various features and elements disclosed herein may be combined with one or more other disclosed features and elements.

[0103] Those skilled in the art will recognize improvements and modifications to the preferred embodiments of this disclosure. All such improvements and modifications are to be considered within the scope of the concepts disclosed herein and the appended claims.

Claims

1. A light-emitting diode (LED) device, comprising: At least one LED chip, the at least one LED chip including a top surface, a bottom surface and a peripheral sidewall connecting the top surface and the bottom surface; A wavelength conversion element disposed on the top surface of the at least one LED chip, the wavelength conversion element comprising at least one fluorescent material; as well as A light-changing material is disposed on the peripheral sidewall of the at least one LED chip, the light-changing material comprising a width measured from the peripheral sidewall, the width being in the range of 15 micrometers (µm) and 100 µm. The light-changing material is coplanar with the top surface of the wavelength conversion element and with the bottom surface of the at least one LED chip.

2. The light-emitting diode (LED) device according to claim 1, wherein, The width of the light-changing material is in the range of 15µm and 50µm.

3. The light-emitting diode (LED) device according to claim 1, wherein, The top surface of the at least one LED chip does not contain the light-changing material.

4. The light-emitting diode (LED) device according to claim 1, wherein, The bottom surface of the at least one LED chip does not contain the light-changing material.

5. The light-emitting diode (LED) device according to claim 1, wherein, The light-changing materials include light-reflecting materials.

6. The light-emitting diode (LED) device according to claim 5, wherein, The light-reflecting material includes molten silica, fumed silica, or titanium dioxide (TiO2) particles suspended in silicone resin.

7. The light-emitting diode (LED) device according to claim 1, wherein, The light-changing materials include light-absorbing materials.

8. The light-emitting diode (LED) device according to claim 1, wherein, The LED device has no base on the bottom surface of at least one LED chip.

9. The light-emitting diode (LED) device according to claim 1, further comprising an anode and a cathode located on the bottom surface of the at least one LED chip.

10. The light-emitting diode (LED) device according to claim 1, wherein, The at least one fluorescent material includes a phosphor.

11. The light-emitting diode (LED) device according to claim 1, wherein, The wavelength conversion element further includes a cover supporting the at least one fluorescent material.

12. The light-emitting diode (LED) device according to claim 1, wherein, The wavelength conversion element includes one of the following: a ceramic phosphor plate, a phosphor in glass, and a phosphor embedded in silicon.

13. The light-emitting diode (LED) device according to claim 1, wherein, The peripheral side of the wavelength conversion element is offset from the peripheral sidewall of the at least one LED chip.

14. The light-emitting diode (LED) device according to claim 13, wherein, The light-changing material is conformal on the peripheral sidewall of the wavelength conversion element and the peripheral sidewall of the at least one LED chip.

15. The light-emitting diode (LED) device according to claim 1, wherein, The light-changing material forms rounded corners at the outer edge of the wavelength conversion element.

16. The light-emitting diode (LED) device according to claim 1, wherein, The light-changing material forms rounded corners at the peripheral sidewall corners of at least one LED chip.

17. The light-emitting diode (LED) device according to claim 1, wherein, The light-changing material forms an extension extending from the peripheral sidewall of the at least one LED chip.

18. The light-emitting diode (LED) device according to claim 1, further comprising a lens on the at least one LED chip.

19. A method for manufacturing a light-emitting diode (LED) device, comprising: Provide at least one light-emitting diode (LED) chip, the at least one LED chip including a top surface, a bottom surface and a peripheral sidewall connecting the top surface and the bottom surface; A wavelength conversion element is disposed on the top surface of the at least one LED chip, the wavelength conversion element comprising at least one fluorescent material. A light-changing material is formed on the top surface and the peripheral sidewall of the at least one LED chip, the light-changing material including a width measured from the peripheral sidewall, the width being in the range of 15 micrometers (µm) and 100 µm; as well as Remove a portion of the light-changing material located on the top surface of the at least one LED chip, such that the light-changing material is coplanar with the top surface of the wavelength conversion element and coplanar with the bottom surface of the at least one LED chip.

20. The method according to claim 19, wherein, Forming the light-changing material includes laminating a preform of the light-changing material onto the top surface and the peripheral sidewalls.

21. The method according to claim 19, wherein, The light-changing material forms rounded corners at the peripheral sidewall corners of at least one LED chip.

22. The method of claim 19, further comprising disposeding the wavelength conversion element on the top surface of the at least one LED chip prior to forming the light-changing material.

23. The method according to claim 22, wherein, Removing a portion of the light-changing material located on the top surface of the at least one LED chip includes removing a portion of the light-changing material located on the top surface of the wavelength conversion element.

24. The method according to claim 23, wherein, The light-changing material forms rounded corners at the outer edge of the wavelength conversion element.

25. The method according to claim 19, wherein, The at least one LED chip includes a plurality of LED chips arranged on a common support.

26. The method of claim 25, wherein, Forming the light-changing material includes laminating a preform of the light-changing material onto the top surface and the peripheral sidewall of each of the plurality of LED chips.

27. The method of claim 26, further comprising separating each of the plurality of LED chips from the common support.

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