LED device and method

Abstract

Light emitting diode (LED) devices and systems include a superstrate (e.g., a light transmissive layer), at least one area of ​​wavelength conversion material in the light transmissive layer, and an LED attached to the superstrate at the location of the wavelength conversion material. An encapsulant layer is formed on and / or around the LED using an opaque or clear material. An additional color filter layer is optionally applied to the light transmissive layer. Methods for making LED devices and systems include providing a superstrate having a wavelength conversion material formed therein, attaching the LED to the superstrate at a die attach layer, forming a conductive surface on a side of the LED opposite the die attach layer, dispensing a sealant layer to at least partially encapsulate the LED, and forming one or more electrical traces to electrically interconnect the conductive surfaces of at least some of the LEDs to each other.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. patent application serial number 15 / 997,350 filed on June 4, 2018, the entire contents of which are incorporated herein by reference, which is a part continuation application from U.S. patent application serial number 15 / 993,540 filed on May 30, 2018 and claims priority to the prior U.S. patent application. Technical Field

[0003] The present subject matter generally relates to light emitting devices, systems and / or methods. More specifically, the subject matter disclosed herein relates to color filters for LEDs. Background Art

[0004] A light emitting diode or "LED" is a solid-state device that converts electrical energy into light. LEDs can be used in light emitter devices or components to provide different colors and light patterns that can be used in various lighting, display, and optoelectronic applications. One such application is the use of LEDs in video screens. An LED video display typically includes an array of red, green, and blue LEDs mounted on a single electronic device attached to a printed circuit board (PCB) that controls the output of each electronic device.

[0005] Conventional LED arrays typically have a transparent encapsulant covering the individual LEDs to protect the device and maximize the efficiency of the device. When used in applications such as video screens, reducing and / or increasing the amount of reflected light would be additionally desirable. Controlling the amount of reflected light can provide benefits such as increased contrast, image clarity, and consistent light color quality across viewing angles.

[0006] Another known problem with LED arrays is the light color quality in the far field. Individual LEDs in a grouped array may have different light output distributions that become more apparent when viewed from a wide viewing angle. For example, certain light color LEDs may have a wider light output cone and thus dominate the overall hue within the viewing area, resulting in undesirable light color quality.

[0007] Therefore, there is a continuing need for improved packaged LED arrays while also considering cost. For example, LEDs of certain light colors may be more expensive to manufacture than other light colors. Summary of the invention

[0008] In some aspects, a light emitting diode (LED) device can have a light transmissive layer and one or more regions of a wavelength conversion material disposed in at least a portion of a first side of the light transmissive layer. One or more LEDs can be disposed on the light transmissive layer such that light emitted from the one or more LEDs can pass through the wavelength conversion material, and an opaque encapsulant can be disposed around and between the one or more LEDs.

[0009] In other aspects, a method of manufacturing a light emitting diode device may include providing a light transmitting layer, disposing a wavelength conversion material in at least a portion of the light transmitting layer, attaching one or more LEDs to a first side of the light transmitting layer such that light emitted from the one or more LEDs can be transmitted through the wavelength conversion material, and then applying an opaque sealant around the one or more LEDs.

[0010] In another aspect, a light emitting diode (LED) device may include a light transmissive layer and one or more regions of a color filter material disposed on at least one side of the light transmissive layer. One or more LEDs may be disposed on the light transmissive layer such that light emitted from the one or more LEDs may pass through the color filter material, and an opaque sealant may be disposed around and between the one or more LEDs.

[0011] Multicolor LED devices as disclosed herein may have several benefits over conventional multicolor LED devices.By combining LEDs with additional features such as phosphor conversion materials and color filter layers, lower cost devices with better far field and less pixelation can be constructed.

[0012] Lower costs can be achieved by replacing more expensive LEDs (such as red) with cheaper die light colors (such as blue and optionally green). Multicolor LED devices can be constructed through the use of wavelength conversion layers combined with color filters on the light emitting surface, which can produce colors not provided by LEDs. For example, the wavelength of a blue LED and / or a green LED can be altered to produce a longer wavelength light color such as red. In addition, the consolidation of components can reduce costs and simplify the manufacturing process.

[0013] The use of a phosphor layer can also improve the far field due to the naturally non-directional emission from the phosphor. This can reduce the color shift that can sometimes be observed when viewing a video screen at a wide angle.

[0014] The "screen door effect" or SDE is another problem that can occur in LED video displays. SDE occurs when the light source is significantly smaller than the screen "pitch" (i.e., the grid of pixels when each pixel is a multi-color LED array). This phenomenon can occur in many types of video displays, but is particularly common in LED screens. Phosphors, diffusers, and other color filter layers as disclosed herein can be used to reduce SDE while maintaining individual light color quality by spreading the light of the source within the component to fill out the spaces or "gaps" between arrays in the grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] A full and enabling disclosure of the present subject matter is more particularly set forth in the remainder of this specification, which includes references to the accompanying drawings related to one or more embodiments, in which:

[0016] Figure 1 is a cross-sectional side view of an LED device according to the disclosure herein;

[0017] Figure 2A is a top view of an LED device according to the disclosure herein;

[0018] Figure 2B is a bottom view of an LED device according to the disclosure herein;

[0019] Figure 3A is an isometric top view of an LED device according to the disclosure herein;

[0020] Figure 3B is an isometric bottom view of an LED device according to the disclosure herein;

[0021] Figure 4 is a flow chart of a method of manufacturing an LED device according to the disclosure herein;

[0022] Figure 5 is a cross-sectional side view of another LED device according to the disclosure herein;

[0023] Figure 6 is a cross-sectional side view of another LED device according to the disclosure herein;

[0024] Figure 7 is a cross-sectional side view of another LED device according to the disclosure herein;

[0025] Figure 8 is a cross-sectional side view of another LED device according to the disclosure herein;

[0026] Fig. 9 is a cross-sectional side view of another LED device according to the disclosure herein.

[0027] Fig.10 is a cross-sectional side view of another LED device according to the disclosure herein;

[0028] Fig.11A is a cross-sectional side view of another LED device according to the disclosure herein;

[0029] Fig. 11B yes Fig.11A Isometric top view of LED device;

[0030] Figures 12A-12B is a cross-sectional side view of another LED device according to the disclosure herein;

[0031] Fig. 12C yes Fig. 12A Isometric top view of LED device;

[0032] Fig.13 is a flow chart of a method of manufacturing an LED device according to the disclosure herein;

[0033] Fig.14 is a cross-sectional side view of another LED device according to the disclosure herein;

[0034] Fig.15 is a cross-sectional side view of another LED device according to the disclosure herein;

[0035] Fig.16 is a graph comparing emission spectra;

[0036] Fig.17A is a simplified diagram illustrating an example panel of LEDs; and

[0037] Fig. 17B is a cross-sectional side view of a portion of an LED panel. DETAILED DESCRIPTION

[0038] In some aspects, the solid-state lighting devices, LED devices and / or systems described herein and methods for making the same may include various solid-state light emitter electrical configurations, color combinations and / or circuit components for providing solid-state lighting devices with improved efficiency, improved emission profiles, enhanced output and / or optimized light color generation. Such devices and methods as disclosed herein are advantageously less costly, more efficient, realistic, clean and / or vivid than some other solutions.

[0039] Unless otherwise defined, the terms used herein should be interpreted as having the same meaning as commonly understood by a person of ordinary skill in the art to which the subject matter belongs. It will be further understood that the terms used herein should be interpreted as having the same meaning as the corresponding meaning in the context of this specification and the relevant art, and should not be interpreted in an idealized or overly formal sense, unless expressly defined in this document.

[0040] Various aspects of the subject matter are described herein with reference to cross-sectional views, stereograms, elevations and / or plan views, which are schematic illustrations of the idealized aspects of the subject matter. Due to, for example, manufacturing techniques and / or tolerances, changes from the illustrated shapes are foreseeable, so aspects of the subject matter should not be interpreted as being limited to the specific shapes illustrated herein. The subject matter can be embodied in different forms and should not be interpreted as being limited to the specific aspects, scopes or embodiments set forth herein, but will include deviations in shape. These deviations may be caused by, for example, manufacturing. In the accompanying drawings, for clarity, the dimensions and relative dimensions of the layers and regions are exaggerated. The actual thickness of the layer may be different from the illustrated shape. The regions illustrated or described as square or rectangular will generally have rounded or curved features due to normal manufacturing tolerances. Therefore, the regions illustrated in the accompanying drawings are schematic in nature, and the shapes of these regions are not intended to illustrate the exact shapes of the device regions.

[0041] Unless the absence of one or more elements is specifically stated, the terms "include", "comprising" and "having" as used herein should be interpreted as open terms, ie, do not exclude the existence of one or more elements. Throughout this specification, similar reference numerals refer to similar elements.

[0042] It will be understood that when an element such as a layer, region, or substrate is referred to as being "on" another element, the element may be directly on the other element, or there may be an intermediate element. In addition, relative terms such as "on...", "above", "up", "top", "down", or "bottom" are used herein to describe the relationship of one structure or part to another structure or part as illustrated in the accompanying drawings. It will be understood that relative terms such as "on...", "above", "up", "top", "down", or "bottom" are intended to include different orientations of the device in addition to the orientations drawn in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, the structure or part described as being "above" other structures or parts will now be oriented "below" the other structures or parts.

[0043] As used herein, the terms "electro-activated emitter" and "emitter" are synonymous terms and refer to any device capable of producing visible wavelength radiation or near-visible wavelength radiation (e.g., from infrared to ultraviolet), including, for example, but not limited to, xenon lamps, mercury lamps, sodium lamps, incandescent lamps, and solid-state emitters including LEDs or LED chips, organic light emitting diodes (OLEDs), and lasers.

[0044] The terms "solid state light emitter", "solid state emitter" and "light emitter" are synonymous terms and refer to LED chips, laser diodes, organic LED chips and / or any other semiconductor devices that are preferably arranged as a semiconductor chip including one or more semiconductor layers, a substrate and one or more contact layers, wherein the one or more semiconductor layers may include silicon, silicon carbide, gallium nitride and / or other semiconductor materials, the substrate may include sapphire, silicon, silicon carbide and / or other microelectronic substrates, and the one or more contact layers may include metal and / or other conductive materials.

[0045] As used herein, the terms "group", "segment", "series", and "set" are synonymous terms. As used herein, these terms generally describe how multiple LEDs are electrically connected, such as mutually exclusive groups / segments / sets in series, parallel, mixed series / parallel, common anode or common cathode configurations. Segments of LEDs can be configured in a variety of different ways and can have circuits of varying functionality associated therewith (e.g., driver circuits, rectification circuits, current limiting circuits, shunts, bypass circuits, etc.), as discussed, for example, in the following commonly assigned and co-pending documents, namely, U.S. patent application serial number 12 / 566,195 filed on September 24, 2009, U.S. patent application serial number 13 / 769,273 filed on February 15, 2013, U.S. patent application serial number 13 / 769,277 filed on February 15, 2013, U.S. patent application serial number 13 / 235,103 filed on September 16, 2011, U.S. patent application serial number 13 / 235,127 filed on September 16, 2011, and U.S. Patent No. 8,729,589 issued on May 20, 2014, the entire disclosure of each of which is hereby incorporated by reference herein.

[0046] The term "targeted" refers to an LED chip segment configuration configured to provide predefined lighting characteristics, i.e., specified parameters for a lighting device. For example, a targeted spectral power distribution may describe the characteristics of light generated at a specific power, current, or voltage level.

[0047] The term "opaque" refers to a material, surface, etc. that is non-transparent or opaque on at least a portion of the visible spectrum. "Opaque" can also be applied to the entire visible spectrum. The term "opaque" is considered to be less than 30% of the light received. Materials can also be opaque due to light absorption or light reflection. White materials, for example, can also be opaque and reflective. Some materials can be opaque at certain wavelengths and transparent at other wavelengths. As a non-limiting example, a red pigment can act as a color filter due to absorption of light wavelengths below about 600nm (under which conditions it is opaque) and transmission of light wavelengths above about 600nm (under which conditions it is transparent).

[0048] The apparatus, systems and methods disclosed herein may employ red chips, green chips and blue chips. In some aspects, the chips used in the blue-shifted yellow (BSY) device may target different bins as set forth in Table 1 of commonly owned, assigned and co-pending U.S. patent application Ser. No. 12 / 257,804 (disclosed as U.S. Patent Publication No. 2009 / 0160363), the entire disclosure of which is incorporated herein by reference. The apparatus, systems and methods herein may employ, for example, ultraviolet (UV) chips, cyan chips, blue chips, green chips, red chips, amber chips and / or infrared chips.

[0049] The term "substrate" as used herein in connection with a lighting device refers to a mounting member or element on which, in which, or attached to which a plurality of solid-state light emitters (such as LEDs) may be arranged, supported, and / or mounted. The substrate may be, for example, a component substrate, a chip substrate (such as an LED substrate), or a sub-panel substrate. Exemplary substrates useful for lighting devices as described herein may include, for example, a printed circuit board (PCB) and / or related components (such as, but not limited to, a metal core printed circuit board (MCPCB), a flexible circuit board, a dielectric laminate, a ceramic-based substrate, etc.), a ceramic plate or metal plate having FR4 and / or electrical traces arranged on one or more surfaces thereof, a high reflectivity ceramic (such as alumina) support panel, a transparent or light-transmitting material (such as glass, plastic, sapphire), and / or a mounting element of various materials and configurations arranged to receive, support, and / or conduct electrical power to a solid-state emitter. The electrical traces described herein provide electrical power to the emitter for electrical activation and lighting of the emitter. The electrical traces may be opaque or transparent, and / or may be covered via a reflective covering such as a solder mask material, Ag, or other suitable reflector.

[0050] In some embodiments, one substrate may be used to support multiple groups of solid-state light emitters and at least some other circuits and / or circuit elements, such as power or current drive components and / or current switching components. In other aspects, two or more substrates (e.g., at least a primary substrate and one or more auxiliary substrates) may be used to support multiple groups of solid-state light emitters and at least some other circuits and / or circuit elements, such as power or current drive components and / or temperature compensation components. The first and second substrates (e.g., a primary substrate and an auxiliary substrate) may be disposed above and / or below each other and along different planes, adjacent to each other (e.g., side by side), having one or more coplanar surfaces disposed adjacent to each other, arranged vertically, arranged horizontally, and / or arranged in any other orientation relative to each other.

[0051] LEDs that can be used with lighting devices as disclosed herein can include horizontal structures (where both electrical contacts are on the same side of the LED chip) and / or vertical structures (where the electrical contacts are on opposite sides of the LED chip). Horizontally structured chips (with or without a growth substrate) can be flip-chip soldered (e.g., using solder) to a carrier substrate or printed circuit board (PCB), or can be wire-bonded. Vertically structured chips (with or without a growth substrate) can have a first terminal that is soldered to a carrier substrate, a mounting pad, or a printed circuit board (PCB), and have a second terminal that is wire-bonded to a carrier substrate, an electrical component, or a PCB.

[0052] Electrically activated light emitters (e.g., solid state emitters) may be used individually or in groups to emit light, thereby stimulating emission of one or more lumiphoric materials (e.g., phosphors, scintillators, luminescent inks, quantum dots) and generating light at one or more peak wavelengths or having at least one desired perceived color (including a combination of light colors that may be perceived as white). The inclusion of luminescent (also referred to as "luminescent") materials in lighting devices as described herein may be achieved by application of a direct coating of the material on a lumiphor support element or lumiphor support surface (e.g., by dispensing, printing, etc.), by adding such material to a lens, and / or by embedding or dispersing such material within a lumiphor support element or surface. Methods for making LEDs having a planarized phosphor coating integrated therewith are discussed by way of example in U.S. Patent Application Publication No. 2008 / 0179611 filed on September 7, 2007 by Chitnis et al., the entire disclosure of which is hereby incorporated by reference herein.

[0053] Other materials, such as light scattering elements (e.g., particles) and / or refractive index matching materials can be associated with elements or surfaces containing luminescent materials. Apparatus and methods as disclosed herein can include LEDs of different light colors, one or more of which can be white light emitting (e.g., including at least one LED with one or more luminescent materials).

[0054] In some aspects, one or more short wavelength solid state emitters (e.g., blue LEDs and / or cyan LEDs) may be used to stimulate emission from a mixture of luminescent materials or discrete layers of luminescent materials including red, yellow, and green luminescent materials. LEDs of different wavelengths may be present in the same group of solid state emitters, or may be provided in different groups of solid state emitters. A wide variety of wavelength conversion materials (e.g., luminescent materials, also known as luminophores or luminescent media; for example, as disclosed in U.S. Patent No. 6,600,175, issued on July 29, 2003, and in U.S. Patent Application Publication No. 2009 / 0184616, filed on October 9, 2008, the entire disclosures of each of which are hereby incorporated herein by reference) are well known and available to those skilled in the art.

[0055] In some aspects, lighting devices and systems as described herein include multiple sets of solid-state light emitters that target different light colors (e.g., one set targets a first light color and at least a second set targets a second light color that is different from the first light color). In some aspects, each of the multiple sets includes at least two solid-state light emitters of the same light color (e.g., with peak wavelengths coinciding). In some aspects, each of the multiple sets of solid-state emitters is adapted to emit one or more different light colors. In some aspects, each of the multiple sets of solid-state emitters is adapted to emit one or more light colors that are distinguishable relative to each other (e.g., where each solid-state emitter set emits at least one peak wavelength that is not significantly emitted by another solid-state emitter set). Aspects of targeting and selectively activating solid-state emitter sets in accordance with the present subject matter can be provided using circuits and / or techniques described in commonly assigned and co-pending U.S. patent application Ser. No. 14 / 221,839, the disclosure of which has been previously incorporated by reference above.

[0056] The term "color" when referring to a solid state emitter refers to the color and / or wavelength of light emitted by the device after an electric current is passed through it.

[0057] Some embodiments of the current subject matter may use solid state emitters, emitter packages, fixtures, luminescent materials / elements, power supply elements, control elements, and / or methods such as those described in the following documents: U.S. Patent Nos. 7,564,180; 7,456,499; 7,213,940; 7,095,056; 6,958,497; 6,853,010; 6,791,119; 6,600,175; 6,201 ,262, 6,187,606, 6,120,600, 5,912,477, 5,739,554, 5,631,190, 5,604,135, 5,523,589, 5,416,342, 5,393,993, 5,359,345, 5,338,944, 5,210,051, 5,027,168, 5,027,168, 4,966,862 and / or 4 ,918,497, and U.S. Patent Application Publication Nos. 2009 / 0184616, 2009 / 0080185, 2009 / 0050908, 2009 / 0050907, 2008 / 0308825, 2008 / 0198112, 2008 / 0179611, 2008 / 0173884, 2008 / 0121921, 2008 / 0012036, 2007 / 02 53209, 2007 / 0223219, 2007 / 0170447, 2007 / 0158668, 2007 / 0139923 and / or 2006 / 0221272, U.S. patent application serial number 11 / 556,440 filed on December 4, 2006; the disclosures of the above patents, published patent applications and patent application serial numbers are hereby incorporated by reference as if fully set forth herein.

[0058] As used herein, the terms "lighting device" and "module" are synonymous and are not limited except that they can emit light. That is, a lighting device can be a device or apparatus that illuminates an area or volume such as a structure, a swimming pool or spa, a room, a warehouse, an indicator, a road, a parking lot, a vehicle, a sign (such as a road sign, a billboard), a ship, a toy, a mirror, a container, an electronic device, a boat, an aircraft, a stadium, a computer, a remote audio device, a remote video device, a cell phone, a tree, a window, an LCD display, a cave, a tunnel, a courtyard, a street lamp post, or a device or array of devices that illuminate an enclosure, or for edge or backlighting (such as backlighting posters, signs, LCD displays), light bulbs, light bulb replacements (such as for replacing AC incandescent lamps, low voltage lamps, fluorescent lamps, etc.), outdoor lighting, security lighting, exterior residential lighting (wall mounts, stake / pole mounts), ceiling fixtures / sconces, under cabinet lighting, lamps (floor and / or table and / or desk), landscape lighting, track lighting, task lighting, specialty lighting, ropes (rope lights), Lighting devices as used herein may further be used not only to illuminate an object or area but also for direct viewing of a device such as an LED video display.

[0059] Phosphors or phosphor compounds as disclosed herein may in some aspects include one or more of a variety of wavelength conversion materials or light color conversion components (including luminescent materials). Examples of luminescent materials (luminophores) include phosphors, cerium-doped yttrium aluminum garnet (YAG) (e.g., LuAG:Ce), nitrides, oxynitrides, scintillators, day glow ribbons, nanophosphors, quantum dots (e.g., such as quantum dots provided by NNCrystal USA, Inc. of Fayetteville, Arkansas), and inks that emit a glow in the visible spectrum upon irradiation with (e.g., ultraviolet) light. In conjunction with solid-state light emitters and LEDs, inclusion of luminophores in wavelength conversion components or related components as disclosed herein may be achieved by providing a layer (e.g., a coating) of such material attached to the solid-state emitter and / or by dispersing the luminescent material in a clear encapsulant (e.g., an epoxy- or silicone-based curable resin or other polymer or ceramic matrix) arranged to cover or partially cover one or more solid-state light emitters. One or more luminescent materials useful in devices as described herein may be down-converting or up-converting, or may include a combination of both types.

[0060] The use of wavelength conversion materials can provide additional properties and / or characteristics to the LED devices, including, for example, improved long-term reliability (e.g., improved properties for over 1000 hours or more at 85°C, 105°C and / or 125°C conditions), reduced bubbling around the solid-state light emitter, greater viewing angle, lower dCCT color spread, cooler phosphor temperature, brighter emission, improved sulfur resistance and / or smaller color point spread, including all or any combination of such features.

[0061] The presently disclosed subject matter is directed to embodiments of LED structures having light sources including LEDs. LED packages can be arranged in different ways and be relatively small, while still being efficient, reliable, and cost-effective. Compared to similar LED packages with fully hemispherical encapsulants, embodiments disclosed herein can have encapsulants of different shapes and can emit light with improved or similar efficiency. In some embodiments where multiple LEDs are mounted on a substrate, the spacing between each LED chip can be controlled to optimize the light intensity output from the LED package. LED packages disclosed herein can also be smaller and less expensive to manufacture.

[0062] The disclosure herein is described with reference to example embodiments, but it is understood that the disclosure herein can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In particular, the disclosure herein is described below in relation to certain LED devices having LEDs in different configurations, but it is understood that the disclosure herein can also be used for many other LED packages having other LED configurations. In addition to the shapes described below, LED packages employing the disclosure herein can also have many different shapes (e.g., rectangular), and solder pads and attachment pads can be arranged in many different ways. In other embodiments, the emission intensity of different types of LEDs can be controlled to change the emission of the overall LED package.

[0063] The embodiments described herein carry references to one or more LEDs, but according to the disclosure herein and in some aspects, an LED as used herein may include an LED chip or one or more any other suitable structures. For example, an LED as used herein may be a separate junction of a monolithic LED. For example, instead of being a completely separate LED chip, each LED may be an LED region all on a common substrate, which may have different types of monolithic junctions. The gaps between the LEDs and on the common substrate may extend to certain layers, or may extend all the way to or from the common substrate. Thus, a monolithic LED may include more than one LED junction on a common substrate, and gaps between the LEDs may be formed to at least partially separate the LEDs.

[0064] In addition to those shapes and sizes shown, the components described herein may also have different shapes and sizes, and one or a different number of LEDs may be included. It is also understood that the embodiments described below use coplanar light sources, but it is understood that non-coplanar light sources may also be used. It is also understood that the LED light source may include multiple LEDs, and the multiple LEDs may have different emission wavelengths. As described above, in some embodiments, at least some of the LEDs may include blue-emitting LEDs covered with yellow phosphors together with red-emitting LEDs, so that white light is emitted from the LED package. In some embodiments, the LEDs may be phosphor-converted red or green lights. In a multi-LED package, the LEDs may be interconnected in series or in different series and parallel combinations.

[0065] Coatings, sealants, sealant layers, etc. are disclosed herein, and these coatings, sealants, sealant layers, etc. may include any material that provides mechanical protection, chemical protection, and / or environmental protection for substrates, reflective layers, or other LED components. The coating, sealant, and / or sealant layer may be configured as a layer covering a substantially horizontal or vertical surface in some embodiments, and may include a layer disposed on top of another layer, surface, or structure, whether or not completely surrounding all sides of another layer, surface, or structure in some aspects. In some embodiments, the coating, sealant, and / or sealant layer may include or may be composed of a dielectric as disclosed herein. It is also understood that when a feature or element such as a layer, region, sealant, or submount is referred to as being "on" another element, the feature or element may be directly on another element, or there may also be an intermediate element. In addition, relative terms such as "inside", "outside", "upper", "above", "lower", "underneath", and "below" and similar terms may be used herein to describe the relationship of a layer or another region. It is understood that these terms are intended to include different orientations of the device in addition to the orientations depicted in the accompanying drawings.

[0066] In certain aspects, the coating materials disclosed herein may include multiple encapsulating layers, coatings, and / or dielectric materials and compounds, including, for example, silicon oxide, silicon nitride, aluminum oxide, titanium dioxide, non-metallic oxides, non-metallic nitrides, tantalum oxide, aluminum, nickel, titanium, tungsten, platinum, combinations thereof, or alloys thereof, etc. In some aspects, such encapsulants, coatings, and / or dielectrics may include one or more materials arranged to provide desired electrical isolation and high thermal conductivity. For example, the dielectric may provide desired electrical isolation between electrical traces and / or between sets of solid-state emitters. In some aspects, such substrates may include ceramics such as aluminum oxide (Al2O3), aluminum nitride (AlN), silicon carbide (SiC), silicon, or plastic or polymer materials such as polyimide, polyester, metal, etc.

[0067] In some cases it is desirable to increase the speed at which LED devices are manufactured. One way to increase manufacturing speed is to assemble multiple components on a single substrate (or "superstrate" as described below) and then separate the grouping into component arrays. This can be particularly useful when creating multi-color component arrays for use in high-density (HD) video displays. Multiple arrays can be created as large sheets and then singulated into individual arrays including multiple LED devices for each singulated portion.

[0068] In addition, eliminating parts can simplify the manufacturing process and improve light quality. For example, LED devices can be assembled without using or omitting substrates. This can be achieved by assembling LEDs upside down, so that the LEDs are assembled on a transparent "cover plate" or top light transmission layer that will become the outer surface in the finished product. Each component can then be electrically connected through exposed electrical connection points on the opposite (other) side of the LED. The device or equipment therefore does not carry (or default) a traditional "substrate" on the side opposite to the light transmission side of the LED, such as, for example, a ceramic substrate, a metal substrate, or other types of material substrates to which LEDS are often attached. As described herein, an LED device constructed by "upside down" can be considered as a complete LED device without such a substrate. This is not to say that the LED device will not be assembled into a larger (e.g., multi-component) device that includes a substrate later.

[0069] refer to Figure 1 , an example embodiment of an LED device is shown. A light emitting diode (LED) device, generally designated 100, is depicted in a typical assembly orientation, i.e., with the emitting surface in an upward direction. However, construction of the LED device 100 may also occur from the top surface downward. The LED device 100 begins with a cover plate, a light transmissive layer 110, which has an outer surface 112 and a component side surface 114. The light transmissive layer 110 may be made of any suitable light transmissive material, such as, for example, glass, sapphire, epoxy, silicone. The light transmissive layer 110 may optionally have features for changing the light emitting characteristics of the LED device 100, which features will be described in more detail below.

[0070] A die attach layer 120 is provided adjacent to and below the light transmissive layer 110. Where appropriate, the die attach layer may be the same material as the light transmissive layer 110, or the die attach layer may be a different, compatible material. For example, in some embodiments, both the light transmissive layer 110 and the die attach layer 120 may be epoxy or silicone materials, wherein the light transmissive layer 110 is provided in a substantially fully cured state upon assembly and the die attach layer 120 is provided in an uncured, tacky and / or tacky state and subsequently cured. The die attach layer 120 may be applied over the entire surface of the light transmissive layer 110 (e.g., Figure 1 ), or the die attach layer 120 may be applied to selected areas of the light transmitting layer 110 .

[0071] The LED component 130 is then mounted on the die attach layer 120 so that the light emitting surface 132 is in contact with the die attach layer 120. The LED component 130 can be grouped as an array and can include LEDs of multiple (light) colors such as red, green and blue (RGB). In some such embodiments, the LED component 130 is grouped into a red-green-blue array for use in a video display. Mounting the LED component 130 directly on the adhesive die attach layer 120 instead of a traditional substrate advantageously allows a large number of LEDs to be transferred at one time. This can greatly increase the processing speed, which is particularly useful when assembling mini-LEDs or micro-LEDs. Although not yet standardized, the size of a mini-LED is generally described as about 90-250 microns (μm), while the size of a micro-LED is generally considered to be 10-90 μm. This method can also simplify the placement of multi-color LEDs. For example, all LEDs of the first light color can be placed in a single group, followed by large-scale / mass placement of the second and third light colors.

[0072] In some embodiments, the die attach layer 120 may be interspersed or laminated with additional optics layers (not shown). For example, the optics layer may include a light diffusing material or a wavelength converting material. The optics layer may be applied, for example, in selected areas between the superstrate (e.g., light transmissive layer 110) and the top surface of the LED component 130. In other embodiments, the superstrate itself may be modified to include light diffusing material or wavelength converting (e.g., phosphor) material and / or color filter material in selected areas.

[0073] It is further noted that the LED component 130 may refer to any LED chip commonly used in the art, comprising: an LED semiconductor active layer forming the diode itself with an ohmic contact portion, which is typically metallized and presented on the surface for the purpose of electrical and / or mechanical attachment; a passivation layer required to protect the semiconductor and other underlying layers; and optionally a substrate for the chip itself, such as sapphire, silicon carbide or silicon.

[0074] After the LED components 130 are adhered to the die attach layer 120, a sealant layer 140 is applied around and between each LED component 130. The sealant layer 140 can be applied by any coating or dispensing method as described herein or otherwise known in the art, such as dispensing, molding, stenciling, screen printing, spinning, spraying, powder coating, slot coating, etc. The sealant layer 140 can include one or more of the following: epoxy resin, epoxy-polyester hybrid, aliphatic urethane, TGIC polyester, non-TGIC polyester, silicone, silicone modified polyester, silicone hybrid, silicone-epoxy hybrid, acrylic, polycarbonate, or any suitable combination thereof. The sealant layer 140 can be used to control the light output of the LED device 100. For example, the sealant layer 140 can be an electrically insulating and non-reflective or opaque material, such as a white, gray, dark or black material. For the purposes of the disclosure herein, a non-reflective or opaque material is defined as a material or surface that does not reflect or deflect a majority of the light that impinges on it. For example, in a single-sided video display, a black sealant may be preferred. Alternatively, sealant layer 140 may also be a clear material, such as may be used in a double-sided video display or a transparent display, such as a "heads-up" display. Sealant layer 140 may be particularly useful for controlling light output in the far field. Sealant layer 140 may additionally include multiple layers comprising the same or different materials and / or colors. For example, sealant layer 140 may be formed by a black layer followed by a first white layer.

[0075] The LED components 130 are additionally provided with one or more conductive elements 134, such as metal "bumps" or pads, on a side of each LED component 130 remote from the die attach layer 120. These conductive elements 134 can be applied in a variety of conventional ways, such as wire bumping, solder bumping (soldering), plating, or other metallization techniques. In the illustrated embodiment, the conductive elements 134 are electrically connected by applying one or more layers of conductive (usually metal) traces 150 attached to the conductive elements 134. Figure 1Also shown is a solder mask 160 (optional) disposed at least partially over one or more layers of traces 150. In some embodiments, solder mask 160 may be applied to the outermost traces of the multiple layers of traces 150.

[0076] In some embodiments, it is advantageous to place conductive elements 134 on the surface of LED component 130 before applying sealant layer 140. Then, sealant layer 140 is applied on all bottom surfaces, after which the entire surface can be flattened by any method such as grinding, lapping, etc. to form surface S.

[0077] Figure 2A A schematic diagram of a top view of LED device 100 is depicted, illustrating example regions for light transmission. In some embodiments, light extraction features (also referred to as optical elements) (e.g., 110 and 116 described below) may be provided only on specific, localized regions of LED device 100. For example, the regions above LED 130 may be considered optical element regions A, B, and C. The side profiles of these regions are shown in FIG. Figure 1 . In some embodiments, the light transmissive layer 110 may be attached to only one LED 130 (i.e., region A or region B or region C). In other embodiments, the optical element may be attached to any two regions A, B, and C. In still other embodiments, the optical element may be attached to all three regions but not extend over the entire surface of the LED 100. The features of the light transmissive layer 110 may vary between regions, such as having different depths, shapes, etc. Multiple optical elements may be further combined, such as adding a surface texturing structure 116, which will be described in further detail below.

[0078] refer to Figure 2B , the LED device 100 is schematically viewed from a bottom orientation (i.e., opposite the light emitting surface), which shows more details of the traces 150 and the solder mask 160. In the illustrated embodiment, the traces 150 are electrically connected to the conductive elements 134 in the array of LED components 130 and extend beyond the boundaries of the LED components 130 to provide attachment points for external circuits. For example, the traces 150 can be used to mount the LED device 100 on a substrate or printed circuit board (PCB). In some embodiments, multiple layers of electrical traces can be constructed on the lower surface of the LED device 100 to add more functionality or avoid the need for a circuit board. This will be described in more detail below.

[0079] Figure 3A-3B An isometric view of the completed LED device 100 is shown. Figure 3A1 is a top view in which the LED component 130 can be seen through the light transmissive layer 110 and the die attach layer 120. The sealant layer 140 extends around the lower portion of the LED device 100. In this example embodiment, the sealant layer 140 is a black sealant layer. Figure 3B 1 is a bottom view showing traces 150 and solder mask 160 disposed on the bottom surface of the LED opposite the die attach layer 120. The solder mask 160 can be used, for example, to prevent short circuits when soldering the LED device 100 to a PCB.

[0080] A corresponding example method of manufacturing an LED device (eg, LED device 100) is illustrated in Figure 4 First, a light transmissive "superstrate" (e.g., light transmissive layer 110) is prepared (step 1). The superstrate can be prepared with a smooth or textured outer surface, as described above. The light transmissive layer can be clear, or can have diffusers or other wavelength conversion materials added (e.g., as previously described "optics layer"). Next (step 2), a die attach layer (e.g., die attach layer 120) is applied to the superstrate. For example, the die attach layer can be a light transmissive epoxy or silicone die attach adhesive.

[0081] The LED (e.g., LED component 130) is then pressed into the die attach layer (step 3) so that the light emitting surface is in contact with the die attach layer, and the die attach layer is then cured (step 4). The LED can be applied to the die attach layer by a variety of known methods, including pick-and-place or direct tape transfer. The LEDs can be transferred en bloc, for example, from a tape, where the tape is then removed and the die attach surface is cleaned and prepared for the next step. After the die attach layer is cured, the LED can have conductive elements (e.g., metal bumps) applied to the exposed electrical connections. Optionally, the LED can be plated using direct metallization (step 5). Alternatively, the LED can be pre-bumped or have a thick metal layer applied at the wafer level before being attached to the die attach layer.

[0082] At this point, the LEDs are firmly fixed to the cover plate by their light-transmitting surfaces, and the volume of the LEDs is exposed. A sealant layer is then applied to the LEDs (step 6). The sealant layer may be applied so that it completely covers all exposed surfaces of the LEDs including electrical connections and / or metal bumps. After curing, a thin layer of the sealant layer is then removed as needed to expose the metal connection points and flatten the surface (step 7). The removal or flattening of the sealant portion may be achieved, for example, by grinding, polishing, grinding or sanding. Next, electrical traces (e.g., 150) are applied to the metal bumps (step 8) by any suitable, conventional circuit laying method. After depositing the metal traces, a layer of solder mask may be optionally applied according to design requirements (step 9). This may be achieved, for example, by screen printing or by utilizing a photo-imagable solder mask. The transmissive material sheet may then be post-processed by separating (e.g., by dicing) multiple portions of the LED device, each of which includes multiple LEDs that may be configured as individual LED arrays (step 10). The diced components can then be further sorted and prepared for installation into larger LED devices.

[0083] As mentioned previously, LED devices as disclosed herein may also have additional, optional features that affect light output and, in particular, improve far-field viewing.For example, the superstrate may be treated to create a surface texturing structure. Figure 5 An LED device 100 is depicted having an example surface texturing structure 116 on an outer surface 112 of a light-transmitting layer 110. The textured structure 116 may be pre-formed on the light-transmitting layer 110, or the textured structure may be formed during or after manufacturing the LED device 100. For example, during the process of forming the light-transmitting layer 100, the textured structure 116 may be embossed into the light-transmitting layer 110 as the textured structure is formed, or the textured structure may be formed at a later point in the process (e.g., see Figure 4) is created using conventional methods such as cutting, molding, embossing, or etching. Materials can be added, removed, or reshaped. The textured structure 116 can be the same material as the light-transmitting layer 110, or the textured structure can be a different material. For example, one method of producing the textured structure 116 is to form the light-transmitting layer 110 on a ceramic master. Ceramic materials can have natural surface variations that produce the pattern of the textured structure 116. In this case, the surface variations can be considered to be random or natural. Alternatively, the variations can also be prescribed, such as, for example, in a regular, repeating, predetermined, or designed pattern. The pattern of the textured structure 116 can be suitable for achieving various effects, and it can be a prescribed (also referred to as a regular) grid pattern that acts as a lens, or a random pattern. In some aspects, the pattern is a microstructure pattern, having, for example, a size of the order of microstructures (e.g., 1-100 μm). In some embodiments for the surface texturing structure 116 having a microstructure pattern, the microstructure pattern is positioned in a prescribed (also referred to as regular) or random pattern on the outer surface 112 of the light-transmitting layer 110. The textured structure 116 can be uniform across the entire outer surface of the cover sheet, or the textured structure can be applied in targeted areas, such as with respect to Figure 2A For example, the textured structures 116 may have features aligned with the LEDs 130 (e.g., regions A, B, and or C). Some LEDs 130 may have different features on or beside them than other LEDs. Different regions A, B, and C may have the same or different textured structures 116, which may vary in size, height, shape, location, etc. It is also contemplated that the microstructures may be unpatterned in whole or in part.

[0084] There are several advantages to manufacturing LED devices (e.g., 100) without or without a substrate and with a surrounding sealant. Using this method, individual multi-color arrays of LEDs or larger matrices of LEDs can be quickly produced. Adhering the LEDs to the epoxy die attach layer provides a robust mechanical design and is compatible with rapid processing methods such as mass transfer. In addition, the device can be thinner and have a lower cost than conventional LED devices produced on a substrate. This allows for increased packaging density. The use of a sealant, especially a dark or black sealant, can improve the consistency of far-field light and improve the effective contrast under ambient light. In addition, the electrical connections to the LED die can be made all together using standard wafer or PCB board level processing.

[0085] refer to Figure 6, the LED components 130 may also have features applied to the light emitting surface 132 to change the light output. In some embodiments, in addition to or in place of the microstructure pattern or the textured structure, pattern elements may also be provided on the surface of one or more LED components 130 adjacent to the die attach layer 120. This can be achieved at the LED wafer level by adding a layer to the back side or by creating a pattern using a removal process (such as those conventionally used on sapphire substrates) before epitaxial / epitaxial layer (epi) growth. This can be in the form of a material M deposited on the light emitting surface 132. The material M is a material with a pattern and may include, for example, sapphire, metal, organic material, or inorganic material. The material M may be selectively applied to individual LED components 130 in the array, or to all LED components 130 in the array. In addition, the material M may be deposited in a pattern designed to achieve a specific effect (e.g., reshaping or scattering light). This may also be helpful in improving far-field light quality.

[0086] In another embodiment, the LED device 100 may include a shaped edge, such as a curved edge or a Figure 7 The beveled edge B shown in FIG. The beveled edge B can affect the light output pattern and can help make the LED device 100 more robust against external forces that may occur in the assembly. It will be understood that Figure 5-7 The features may be used alone or in any combination.

[0087] Figure 8 Another embodiment of an LED device (generally labeled 200) is depicted. LED device 200 is constructed in the same manner as LED device 100 by placing LED components 130 on a superstrate. (For simplicity, die attach layer 120 is not shown.) After depositing conductive trace 150, insulating layer 170 is added. Then, additional electrical traces such as 152, 154 can be added in sequence as needed according to specific design requirements. Electrical traces 152, 154 are separated by insulating layer 172 and connected to each other and trace 150 by conductive vias 156. LED device 200 can have any number of alternating electrical and insulating layers to meet design requirements, and can also include ground plane and power plane layers. This construction introduces the ability to form more complex circuits than would otherwise be possible by allowing wires to cross each other in different layers (e.g., to allow three-dimensional wiring circuits). LED device 200 thus comprises a multi-layered construction and may also advantageously be populated with other types of active or passive components (not shown) in some embodiments to provide enhanced functionality to LED device 100 .

[0088] Fig. 9An alternative embodiment of a multilayer LED device (generally labeled 300) is depicted. In this embodiment, which is also constructed by a top-down approach, electrical traces 158 are deposited on the component side surface 114 of the light transmissive layer 110 before the LED component 130 is attached. This accommodates the use of LEDs with vertical dies (i.e., LEDs with contacts on opposite sides of the LED). The conductive metal traces 158 can be configured to maximize light output, such as by minimizing size or employing transparent materials such as indium tin oxide (ITO) for the traces. In addition, the electrical traces 158 can be a combination of transparent materials and metal connection points. In other respects, the LED device 300 is similar to the LED device 200. After depositing the first layer of conductive metal traces 158, the LED component 130 is electrically bonded to the electrical traces 158, and the sealant layer 140 is added. Next, alternating electrical trace layers (e.g., 152, 154) and insulating layers 170 can then be added sequentially as needed according to specific design requirements. To make electrical connections, bumps or a thick metal layer can be added to the bottom of the LED component 130. For example, thick copper pads can be placed on the LED component 130 when the LED component is in wafer form. Alternatively, a laser can also be used to clean the pads before applying electrical traces.

[0089] The electrical traces 152, 154 are separated by an insulating layer 172 and connected to each other and the trace 150 by conductive vias 156. This construction introduces the ability to form more complex circuits than would otherwise be possible by allowing wires to cross each other in different layers (e.g., to allow three-dimensional wiring circuits). The LED device 300 thus includes a multi-layered construction and may also be advantageously populated with other types of active or passive components (not shown) in some embodiments to provide enhanced functionality for the LED device 300. Similar to the LED device 200, the LED device 300 may have any number of alternating electrical and insulating layers to meet design requirements, and may also include ground and power plane layers. In addition, it will be understood that features of the LED device 200 and the LED device 300 may be combined. For example, some areas of the LED device may have electrical traces 158 adjacent to the die attach layer 120 to allow the LED components 130 to be bonded to the traces (i.e., oriented in a vertical direction), while other areas of the device have LEDs adhered to the die attach layer 120 in a horizontal orientation.

[0090] In some cases, such as in the case of video screens using multicolor LED components in a red-green-blue (RGB) array, it is also desirable to reduce the cost of manufacturing LED devices. One way to reduce the cost of LED arrays is to replace higher cost LED components with lower cost components. For example, the cost of manufacturing red LEDs may exceed that of manufacturing blue LEDs and / or green LEDs. However, in this case it is desirable to have LEDs that produce red wavelengths in order to produce the broad spectrum of colors required for high quality video displays.

[0091] In other embodiments as disclosed herein, the LED device replaces a red LED or other higher cost LED component with a lower cost blue LED or green LED, and one or more filter layers are provided, the one or more filter layers being configured to transform the spectrum of light emitted from the lower cost LED to a similar spectrum with the replaced component. The filter layers may include, for example, wavelength conversion materials and / or color pigments.

[0092] refer to Fig.10 , an example embodiment of an LED device (generally labeled 400) is shown. Similar to LED device 100, LED device 400 can be constructed from the top down starting from light transmissive layer 110. LED device 400 can have a second, color filter layer 420 applied to the first (i.e., LED attachment) side of light transmissive layer 110. Color filter layer 420 can be formed of one or more color portions and / or color blocking regions depending on design requirements. In a non-limiting example, Fig.10 Colored regions in color filter layer 420 are shown, which may include, for example but not limited to, blue region 422, green region 424, and red region 426. Between and around colored regions 422, 424, and 426, an opaque material 428 (e.g., a white, dark, or black material) may be applied to help prevent color bleed between LEDs and in some cases reduce overall reflection of the component to improve contrast. Color filter layer 420 may be deposited by any suitable method known in the art, such as by photoresist, screen printing, etc., and may include multiple passes, layers, steps, etc. to achieve a multi-color surface.

[0093] After the color filter layer 420 has been deposited, additional wavelength conversion material 430 may be applied. The wavelength conversion material 430 may be Fig.10The wavelength conversion material 430 may be applied over the entire surface of the color filter layer 420 as shown in , or the wavelength conversion material may be applied in a specified area. The wavelength conversion material 430 may be, for example, a phosphor or a phosphor-containing compound described above. It will be understood that the wavelength conversion layer 430 or the color filter layer 420 may also be optionally omitted, with one or the other used alone. In some aspects, a light emitting diode (LED) device may include one or more LEDs, one or more encapsulating layers, and a color filter layer. The thickness of the color filter layer may be approximately 50 μm or less, and the color filter layer may be disposed on one or more encapsulating layers or at least partially within one or more encapsulating layers.

[0094] From this point on, the construction of LED 400 will be similar in some respects to that of the previous embodiments. A die attach layer may be applied to the exposed surface of wavelength conversion layer 430 (not shown for simplicity), and LEDs 442, 444, and 446 may be attached. LEDs 442, 444, and 446 may be aligned with color regions 422, 424, and 426, and they may be LEDs of any light color. The LEDs may, for example, be the same light color as the color region they are aligned with, or the light color of the LEDs may work in conjunction with corresponding wavelength conversion portions and / or color filters to transmit a desired color. LEDs 442, 444, and 446 are then "raised" with conductive elements 134 and surrounded by encapsulation layer 440. Encapsulation layer 440 may be similar to encapsulation layer 140 and formed of an opaque or clear material. If, for example, the encapsulant 440 is formed of a clear material, the LED device 500 may also optionally include a light blocking wall 432 disposed between the LEDs 442, 444, and / or 446. In some aspects, the encapsulant 440 may include a red-passing pigment that brightens the red output by allowing the red spectrum to pass between the LEDs. As with the LED device, the encapsulant 440 is then processed to produce a planarized surface S that can receive the traces 150 and optionally the solder mask 160.

[0095] Figures 11A-11B Another embodiment of an LED device, generally referenced as 500, is depicted. Fig.11A is a cross-sectional side view of LED device 500, and Fig. 11Bis an isometric view of an LED device 500. The LED device 500 also includes wavelength conversion features and / or color filtering features, but in this case, the features are implemented by incorporating light conversion elements into the light transmissive layer 110. In a non-limiting example, the LED device 500 is also built from the light transmissive layer 110. In this case, instead of depositing a color filter layer on an exposed surface of the light transmissive layer 110, the wavelength conversion material is disposed in the light transmissive layer 110. For example, one or more recesses R are formed in the light transmissive layer 110. The recess R may partially or completely pass through the thickness of the light transmissive layer 110, and the wavelength conversion material is deposited in the one or more recesses. The LEDs (e.g., 442, 444, and 446) are then attached to the light transmissive layer in a manner similar to that described above, and at least one LED is aligned with the position of the recess R and the wavelength conversion material 430. In the case where the recess R passes completely through the light transmissive layer 110, a protective layer 450 may be applied to the outer surface of the light transmissive layer 110. The protective layer 450 may provide additional optical functions, such as a diffusing material, a surface texturing structure, and the like.

[0096] Figures 12A-12C Another example embodiment of an LED device, generally referenced as 600, is shown. Fig. 12A and Fig. 12B 6 is an alternative embodiment of an LED device 600 shown in a cross-sectional side view. The light transmission layer 110 is formed with a notch R. The notch R may be formed to completely penetrate the thickness of the light transmission layer 110 (eg, Fig. 12A ), or the notch R may partially penetrate the thickness of the light-transmitting layer 110 (as shown in Fig. 12B ). After the recess R is formed, the lower surface of the light-transmitting layer 110 is covered with a coating 460. The coating 460 may be formed, for example, of an opaque material or a pigmented material, and the coating may help prevent the transmitted light from "crosstalking" between the LEDs 130 on the device. For example, the coating 460 may be a red-transmitting pigment that is light-absorbent for blue and green colors. In the case of the LED device 600, the coating 460 may be a thin coating that may be sprayed on, for example, using the techniques described above or any other suitable technique. The coating 460 covers all surfaces of the recess R. After the coating 460 is applied, the recess R may then be filled with the wavelength conversion material 430.

[0097] One or more individual LEDs are attached to the light transmissive layer 110. In the example embodiment of the LED device 600, the LEDs include two blue LEDs 442 and one green LED 444 having conductive elements 134 deposited on the side of the LEDs 442 and 444 facing away from the light transmissive layer 110.

[0098] Encapsulant layer 44 is applied to a first side (lower side) of LED device 600. Traces 150 are applied to encapsulant layer 440, and solder mask 160 is applied to traces 150. On the opposite (other) side (i.e., the outer side or top side) of LED device 600, additional processing is also implemented. Color filter materials 422, 424 and 426 are disposed on light transmitting layer 110, and opaque material 428 is disposed in selected areas that affect light output. Opaque material 428 can be applied as a masking portion, for example. It can be used to improve the contrast of the transmitted light when viewed under ambient light. In a non-limiting example of LED device 600, color filter materials 422, 424 and 426 are applied in areas corresponding to the light-transmissive upper surface of each LED 442 and 444. However, it is also feasible to provide color filter material attached to only one or some of the LEDs in the array. As seen in Figures 12A-12B , an optional protective layer 450 is applied over the color filter materials 422, 424, and 426 and the opaque material 428. The protective layer 450 may be used to achieve additional optical effects, such as providing a matte finish. Fig. 12C yes Fig. 12A or Fig. 12B , which depicts LED device 600 without optional protective layer 450.

[0099] Fig.13 6 is a flow chart of an example process for forming an LED device similar to LED device 600. In a first step, a light transmissive layer (e.g., 110) is prepared. Preparation may include: optionally applying a color filter layer to a first side of the light transmissive layer, and / or forming one or more notches in the first side. The notches may be formed to pass completely or only partially through the thickness of the light transmissive layer. The notches may be formed, for example, by molding, embossing, or cutting the first side of the light transmissive layer. After the notches are formed, the same side of the light transmissive layer (the first side) may be optionally covered with an intermediate coating (e.g., 460). The coating may be used to achieve different effects on the emitted light. For example, by using a black material, the intermediate coating may be used to block light between different areas of the LED device. In some embodiments, the intermediate coating may be a color filter material with a pigment, such as a material with a red color. The intermediate material may be sprayed on, for example, using the techniques described above or another suitable technique. The intermediate coating may cover substantially the entire first side of the light transmissive layer, including all surfaces of the notches, or the intermediate coating may be selectively applied to portions of the light transmissive layer.

[0100] After the optional application of the intermediate coating, the one or more recesses are filled with a wavelength converting material, such as 430. This may be accomplished by stencil printing or other suitable technique.

[0101] One or more individual LEDs are then attached to the light transmissive layer, for example using the die attach method described above. The LEDs may include, for example, two blue LEDs and one green LED, or alternatively three blue LEDs. These LEDs may then have a conductive element (e.g., 134) applied to the side of the LED away from the light transmissive layer.

[0102] Next, the LED is encapsulated (e.g., 440). The encapsulation may completely cover the LED, including covering the entire first side of the conductive element and the light-transmitting layer. The exposed outer surface of the encapsulation is then processed to produce a planarized surface, and electrical traces are applied to the planarized surface. A solder mask may optionally be applied to the electrical traces.

[0103] Additional processing may then be performed on the second or "outer" side of the light transmissive layer to expose the wavelength conversion material to the outside. After this step, a color filter material may optionally be applied to selected areas of the outer planarized surface, generally replacing the optional color application performed at the previous step. The application of the color filter material may be implemented, for example, by a photoresist method, and the application of the color filter material may occur over several steps to accommodate several colors and / or methods. The color filter material may optionally include a non-reflective masking portion between selected areas. The masking portion can be used for various purposes, such as preventing color bleeding between LEDs or guiding light in a certain direction. The color filter layer may be applied to all or only a portion of the second side of the light transmissive layer, and it is also feasible to provide a color filter material attached to only one or some or all of the LEDs in the array.

[0104] In an optional, additional step, a protective layer (eg, 450) is applied over the color filter material. The protective layer may be used to achieve additional optical effects, such as providing a matte surface.

[0105] The above process can be used to create LED devices with various light conversion characteristics. For example, Fig.14 and Fig.15 Additional possible embodiments of LED devices are illustrated and generally referenced 700 and 800 , respectively. Fig.14The LED device 700 shown in FIG. 7 can form an LED array that uses blue LEDs 442 or consists of only blue LEDs. The LED device 700 has two regions of wavelength conversion material 430 that are used to convert the color of light from the blue LEDs 442 into, for example, green and red colors. A blue color filter material 422 disposed on the blue LEDs 442 without the wavelength conversion material 430 can be used to improve contrast. This can provide benefits such as reduced reflection, less SDE, and improved contrast. An opaque material 428 is disposed between the color filter material 422 and adjacent LEDs to further control light output. A protective layer 450 is disposed on the outer surface of the light transmissive layer 110. In other respects, the LED device 700 is similar to other embodiments, having an encapsulation layer 440, traces 150, and a solder mask 160. Fig.15 An LED arrangement 800 is depicted with one blue LED 442 and two green LEDs 444. In this case, each of the LEDs 442, 444 is arranged so that the emitted light is passed through a wavelength converting material 430. The wavelength converting material may be the same or different between different LEDs.

[0106] Fig.16 is a chart comparing example spectra of LED, red phosphor and RGB color filters. Although blue filter and green filter do not significantly affect the output of corresponding blue light LED chip and green light LED chip, the filter can improve contrast by absorbing other light colors from ambient light. As shown in the figure, the red filter does not significantly affect the output of the red phosphor. However, in some embodiments, the shorter-emitting red phosphor will be affected by absorbing shorter wavelengths. Alternatively, longer (wavelength) (i.e., redder) filters can also be used. As with blue and green, the red filter also improves contrast. In some aspects, a multicolor light emitting diode (LED) device is provided, in which red light is realized by phosphor conversion from shorter wavelength colors, such as, for example, light of blue or green spectrum or wavelength color.

[0107] Fig.17A1 is a simplified diagram illustrating an example panel 1000 of LED devices. Panel 1000 is constructed using an array of LED devices such as those disclosed herein (e.g., 100, 300, 400, 500, etc.). Controller 1002 is configured to power panel 1000 and control individual LEDs to display, for example, pictures and videos on panel 1000. For example, by using LED device 400 in panel 1000, panel 1000 can become suitable for applications such as signboards and indoor / outdoor panels. The opaque encapsulation 440 of LED device 400 allows high contrast within panel 1000 and can reflect a relatively small amount of light. The overall pitch of panel 1000 can therefore be reduced. Panel 1000 can also have an improved viewing angle. In some aspects, a light emitting diode (LED) display device may include a plurality of LED devices (e.g., those LED devices disclosed herein or any other LED device), wherein the LED devices are supported by a main mounting structure and arranged in a matrix of at least 32×32 or larger, and wherein the main mounting structure is free of other electronic semiconductor devices. The main mounting structure may be any suitable structure, such as, for example, a PCB to which the LED components are attached (e.g., soldered). It is then connected to other PCBs that will have such components. In some aspects, the PCB should not have semiconductors or components that generate significant heat on the opposite side of the PCB from the supporting LED array, which is advantageous because: for example, localized heat generation may affect certain LEDs differently than other LEDs, resulting in variations in light color and intensity; manufacturing costs may be simplified and / or reduced; and the structure may be easier to rework.

[0108] Fig. 17B 1000 is a cross-sectional side view of a portion of panel 1000. Panel 1000 includes an area 1006 between LED devices 400, which can be filled, for example, during the sub-panel assembly stage or during full panel assembly. LED devices 400 can be mounted on layer 1008, which can be, for example, a motherboard or a sub-panel, and layer 1008 can be flat or curved convex, concave, cylindrical, spherical or other shapes. Panel 1000 may include one or more pieces 1010 of material, which are added for, for example, protection, anti-glare, contrast, consistent appearance, filtering, light direction, 3D, parallax barrier, double convex array, etc. For example, sheet 1010 may include a protective layer. The protective layer may have a matte surface to reduce specular reflections. The protective layer may also include additional elements, such as, for example, an optical device layer, a diffraction element, a liquid crystal element and / or a polarizing element. Because LED devices (eg, 200, 400, 600, etc.) may be formed with integrated electrical connections and / or active elements, panel 1000 may further lack additional electronic semiconductor devices beyond those contained within the LED component subassembly.

[0109] Although the embodiments described herein are directed to LED arrays, it will be appreciated that the methods and apparatus may also be applied to single LEDs and monochromatic or multi-color arrays. It should also be apparent that other LED devices may be constructed utilizing the arrangements and combinations of color filter materials, masking materials, coating materials, and wavelength conversion materials described herein.

[0110] Although the subject matter has been described herein with reference to specific aspects, features, and illustrative embodiments, it will be understood that the utility of the subject matter is not so limited, but instead extends to and encompasses numerous other variations, modifications, and alternative embodiments as would suggest to one of ordinary skill in the art based on the disclosure herein.

[0111] The aspects disclosed herein may provide, for example, but not limited to, one or more of the following beneficial technical effects: reduced cost of providing solid-state lighting devices; reduced size, volume or footprint of solid-state lighting devices; improved efficiency; improved color rendering; improved thermal management; simplified circuitry; improved contrast, improved viewing angle; improved color mixing; improved reliability; and / or simplified DC or AC operability.

[0112] Various combinations and sub-combinations of the structures and features described herein are also contemplated and will be apparent to those skilled in the art who are aware of the present disclosure. Unless otherwise indicated herein, any of the various features and elements disclosed herein may be combined with one or more other disclosed features and elements. Correspondingly, the subject matter claimed as hereinafter is intended to be broadly interpreted and interpreted as including all such variations, modifications and alternative embodiments within its scope and the equivalents including the claims.

Claims

1. A light emitting diode device, comprising: a light transmissive layer having a first side and a second side, the light transmissive layer being formed with one or more recesses formed in the first side; One or more areas of wavelength conversion material disposed in at least a portion of a first side of a light-transmitting layer, wherein the wavelength conversion material is received in the one or more recesses; one or more light-emitting diodes disposed on the light-transmitting layer such that light emitted from the one or more light-emitting diodes can pass through the wavelength conversion material; and an opaque sealant disposed around and between the one or more light-emitting diodes, wherein a first light-emitting diode of the one or more light-emitting diodes is aligned with a first recess of the one or more recesses and the wavelength conversion material received in the first recess is in direct contact with the first light-emitting diode, and wherein a red-luminescent pigment is contained in the opaque sealant.

2. The light emitting diode device according to claim 1, wherein The opaque sealant includes dark, white or black materials.

3. The light emitting diode device of claim 1, further comprising one or more color filter regions disposed on at least a portion of the first side or the second side of the light transmitting layer and / or on the wavelength conversion material.

4. The light emitting diode device of claim 3, comprising one or more non-reflective masking regions, the one or more non-reflective masking regions being at least partially disposed on and / or between the one or more color filter regions. 5 . The light emitting diode device of claim 3 , further comprising a protection layer disposed on the color filter region or on the wavelength conversion material.

6. The light emitting diode device of claim 1, wherein: The wavelength converting material extends through the thickness of the light transmissive layer.

7. The light emitting diode device of claim 1, wherein: An intermediate coating is disposed between the wavelength conversion material and the light transmission layer.

8. The light emitting diode device of claim 1, comprising a protective layer disposed on the second side of the light transmissive layer.

9. The light emitting diode device of claim 1, comprising one or more layers of electrical traces disposed on a bottom surface of the one or more light emitting diodes opposite the light transmissive layer.

10. The light emitting diode device of claim 9, comprising a conductive element interposed between the one or more light emitting diodes and a first layer of electrical traces in the one or more layers of electrical traces.

11. A light emitting diode device as claimed in claim 9 or 10, comprising a solder mask disposed on at least one of the one or more layers of electrical traces.

12. The light emitting diode device of claim 1, wherein: The light emitting diode device includes an array of light emitting diodes configured to provide a red-green-blue light color array.

13. The light emitting diode device of claim 12, wherein: The light emitting diode array is composed of blue light emitting diodes.

14. The light emitting diode device of claim 12, wherein: The light emitting diode array consists of blue light emitting diodes and green light emitting diodes.

15. A light emitting diode display device, comprising a plurality of light emitting diode devices according to any one of claims 1 to 14, wherein: The plurality of light emitting diode devices are supported by a main mounting structure and arranged in a matrix of at least 32 x 32 or greater, and wherein the main mounting structure is free of other electronic semiconductor devices.

16. A method of manufacturing a light emitting diode device, comprising: providing a light transmissive layer having a first side and a second side; forming one or more recesses in the first side of the light transmissive layer; disposing a wavelength converting material in the one or more recesses; attaching one or more light emitting diodes to the first side of the light transmissive layer such that light emitted from the one or more light emitting diodes can pass through the wavelength conversion material; and applying an opaque sealant around the one or more LEDs, wherein a first LED among the one or more LEDs is aligned with a first recess among the one or more recesses, and a wavelength conversion material received in the first recess is in direct contact with the first LED, and wherein a red-emitting pigment is contained in the opaque sealant.

17. The method of claim 16, comprising: After attaching the one or more light emitting diodes, a conductive element is applied to the electrical contact surfaces of the one or more light emitting diodes.

18. The method of claim 16, wherein: Applying an opaque encapsulant around the one or more light emitting diodes includes applying the encapsulant to the first side of the light transmissive layer.

19. The method of claim 16, comprising: Prior to disposing the wavelength converting material in the one or more recesses, an intermediate coating is applied to the first side of the light transmissive layer.

20. The method of claim 19, wherein: The intermediate coating is black or red.

21. The method of claim 19, comprising: After applying the opaque encapsulant around the one or more light emitting diodes, the opaque encapsulant is planarized to expose at least a portion of the conductive elements of the one or more light emitting diodes.

22. The method of claim 16, comprising applying a color filter material over at least a portion of the light transmissive layer and / or the wavelength converting material.

23. The method of claim 22, wherein: Applying the color filter material includes planarizing the second side of the light transmissive layer and applying the color filter material on the second side of the light transmissive layer.

24. The method of claim 23, wherein: The color filter material is applied in a plurality of steps.

25. The method of claim 22, comprising providing a protective layer on the color filter material.

26. The method of claim 16, comprising planarizing the second side of the light transmissive layer to remove a portion of the light transmissive layer and expose the wavelength converting material.

27. The method of claim 16, comprising providing a protective layer on the second side of the light transmissive layer.

28. The method of claim 21, comprising: One or more layers of electrical traces are applied over the conductive element attached to the one or more light emitting diodes.

29. The method of claim 28, comprising applying a solder mask to at least a portion of an outermost electrical trace of the one or more layers of electrical traces.

30. The method of claim 16, comprising separating the light emitting diode device into a plurality of portions, each of the plurality of portions comprising a plurality of light emitting diodes.

31. A light emitting diode device comprising: a light transmissive layer having a first side and a second side, the light transmissive layer being formed with one or more recesses formed in the first side; one or more regions of color filter material disposed on at least one side of the light transmissive layer; One or more areas of wavelength conversion material disposed in at least a portion of a first side of a light transmissive layer, wherein the wavelength conversion material is received in the one or more recesses; one or more light emitting diodes disposed on the light transmissive layer such that light emitted from the one or more light emitting diodes can pass through the color filter material and the wavelength conversion material; and an opaque sealant disposed around and between the one or more light emitting diodes, wherein a first light emitting diode of the one or more light emitting diodes is aligned with a first recess of the one or more recesses and the wavelength conversion material received in the first recess is in direct contact with the first light emitting diode, and wherein a red glowing pigment is contained in the opaque sealant.

32. The light emitting diode device of claim 31, wherein: The one or more regions of color filter material include a color filter layer having a thickness of 50 μm or less, and wherein the color filter layer is disposed on or at least partially within the opaque encapsulant.

33. A multi-color light emitting diode device manufactured according to the method of any one of claims 16 to 30, wherein: Red light is achieved by phosphors converting light from the blue or green spectrum or wavelength colors.

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