TW202032822A - Color uniformity in converted light emitting diode using nanostructures - Google Patents

Abstract

A nanostructure layer is disclosed. The nanostructure layer includes an array of nanostructure material configured to receive a first light beam at a first angle of incidence and to emit the first light beam at a second angle greater than the first angle, the nanostructure material each having a largest dimension of less than 1000nm.

Description

Color uniformity in conversion light emitting diodes using nanostructures

A typical light emitting diode (LED) experiences source-based or angular discoloration-based non-uniformity of emission. In these LEDs, the color usually varies within a given LED, most significantly depending on the angle of the emitted light from, for example, an active layer that is part of the semiconductor structure of the LED. This corner discoloration (CoA) effect can lead to general non-uniformity and can also lead to more significant visual phenomena, such as "yellow rings" at large corners in the far field of a white LED.

CoA-based non-uniformity can also occur due to the limited interaction between the light emitted by an active layer and a wavelength conversion layer. This limited interaction can occur due to the light transmitted through the wavelength conversion emission at an angle at or close to the normal, so that the light emission interacts with the minimum number of particles in the wavelength conversion layer.

Reveal a kind of nanostructure layer. The nanostructured layer includes a nanostructured material array configured to receive a first beam at a first incident angle and at a second angle greater than the first angle relative to the normal The first light beam is emitted, and each of the nanostructured materials has a largest dimension less than 1000 nm.

Cross reference of related applications

This application claims the priority rights of European patent application 19156833.6 filed on February 13, 2019 and U.S. patent application 16/230,811 filed on December 21, 2018. The full text of each of these cases is incorporated by reference. In this article.

Hereinafter, examples of different lighting systems and/or light-emitting diode implementations will be described more fully with reference to the accompanying drawings. These examples are not mutually exclusive, and features found in one example can be combined with features found in one or more other examples to achieve additional implementations. Therefore, it will be understood that the examples shown in the accompanying drawings are only provided for illustrative purposes and they are not intended to limit the invention in any way. Throughout the text, the same component symbols refer to the same components.

It will be understood that although the terms first, second, third, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms can be used to distinguish one element from another. For example, without departing from the scope of the present invention, a first element can be referred to as a second element and a second element can be referred to as a first element. As used herein, the term "and/or" can include any and all combinations of one or more of the associated listed items.

It will be understood that when an element such as a layer, region or substrate is referred to as being "on" or extending "on" another element, it can be directly on or extend directly on the other element On this other element, there may also be an intermediate element. In contrast, when an element is said to be "directly on" another element or "directly" extends to another element "on", there may be no intervening element. It will also be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element and/or connected or coupled to the other element through one or more intervening elements. One element. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there is no intervening element between the element and the other element. It will be understood that these terms are intended to cover different orientations of elements other than any orientation depicted in the figures.

Relative terms such as "below", "above", "upper", "below", "horizontal" or "vertical" may be used in this text to describe an element, layer or area as shown in the figure. The relationship of another element, layer, or region. It will be appreciated that these terms are intended to cover different orientations of the device other than those depicted in the figures.

Semiconductor light-emitting devices or optical power emitting devices (such as devices that emit ultraviolet (UV) or infrared (IR) optical power) rank among the most effective light sources currently available (hereinafter "LED"). These LEDs may include light emitting diodes, resonant cavity light emitting diodes, vertical cavity laser diodes, edge emitting lasers, or the like. Due to their compact size and lower power requirements, for example, LEDs can be attractive candidates for many different applications. For example, they can be used as light sources (e.g., flashes and camera flashes) for handheld battery-powered devices, such as cameras and mobile phones. They can also be used for, for example, automotive lighting, head-up display (HUD) lighting, garden lighting, street lighting, flashlights for video, general lighting (e.g., home, shop, office and studio lighting, theater/stage lighting and Architectural lighting), augmented reality (AR) lighting, virtual reality (VR) lighting, backlighting as a display and IR spectrum. A single LED can provide less bright light than an incandescent light source, and therefore multi-junction devices or LED arrays (such as monolithic LED arrays, micro LED arrays, etc.) can be used in applications where greater brightness is desired or required.

The improvement of color uniformity in LEDs containing one or more wavelength conversion layers is disclosed. It will be understood that although white LEDs, blue pump light, and phosphor particles are used herein, they are only used as examples. It is worth noting that the disclosures related to white LEDs can be applied to one or more LEDs of other colors. The disclosure related to the blue pump light may be related to the light emitted at one or more other wavelengths. The disclosures related to phosphor particles can be applied to other particle types, layers, or materials that generally provide one or more wavelength conversion properties.

Generally, in white LED applications, an active semiconductor layer provides pump light (for example, blue pump) and uses the pump light to excite particles in a wavelength conversion layer. The wavelength conversion layer may contain color conversion One of the materials of the device, such as phosphor. The white spectrum in such an LED can be achieved based on the contribution from the unconverted residual blue pump and converted phosphor light. As an example, a part of the blue pump light emitted by an active layer may traverse a wavelength converter and may not collide with any wavelength conversion particles so that it passes through the wavelength converter unchanged. A different part of the blue pump light emitted by the active layer can traverse the wavelength converter and can collide with one or more wavelength conversion particles (for example, phosphor particles), so that the resulting optical system from the collision(s) A wavelength-converted light may be lighter than the blue pump light that collides with one or more wavelength-converted particles. The combined blue pump light and converted yellow light can cause the white light output of the LED.

In the example provided above, the spectrum of the converted light can vary depending on the application and can be narrow or broadband. Similarly, in some cases, blue light can be selected to be fully converted to achieve certain colors in the light output by an LED. The wavelength conversion layer can be roughly classified as a powdered phosphor, which is composed of micron-sized converter particles stacked in a polysilicon oxide film or a converter doped into a flat plate of ceramic material. The light scattering properties of the two types of phosphors vary as the powdered phosphor is inherently a volume scattering medium, and the ceramic phosphor may include surface and volume scattering to promote light absorption and conversion.

Scattering in a wavelength conversion layer can indicate the path length of the light that is traversed and absorbed in the wavelength conversion layer and can result in excessive or insufficient conversion of the blue pump light in the phosphor material. As an example, a large amount of scattering in a wavelength conversion layer can correspond to a higher path length, resulting in more collisions (or potential collisions) with wavelength conversion particles in the wavelength conversion layer. Due to the scattering and conversion properties specific to each type of wavelength conversion layer and also due to the selected LED package architecture, source discoloration problems can be experienced in the near field or the far field. The source of color change is characterized by the lack of color uniformity (relative spectral distribution of different components) on the light-emitting surface of a wavelength conversion material. When the source discoloration is projected into the far field using the projection optics, it results in far-field light spots with color non-uniformity at different angles. Source discoloration is usually called angular discoloration, and the two are usually the same phenomenon. Color non-uniformity can lead to undesirable optical effects and lead to sub-optimal LED performance.

The subject disclosed in this article relates to the use of photonic nanostructured layers made of nanostructured materials (such as metasurfaces or metamaterials (e.g., Huygens metasurface), photonic crystals and/or subwavelength diffusers). Technologies and materials to improve the color mixing and color uniformity on the surface of a wavelength conversion layer.

Nanostructured materials (such as supramolecules (for example, supramolecules that produce supersurfaces), photonic crystals, sub-wavelength diffusers, etc.) can be used to implement a nanostructured layer. As used herein, photonic crystals, subwavelength diffusers, and metasurfaces can be periodic configurations of symmetric or asymmetric supramolecular and/or nano antennas. A supramolecular nanostructure layer can include a supramolecular array. A nano antenna nanostructure layer can include one or more nano antennas. As disclosed herein, the nanostructure layer can be incorporated into the design of an LED device with a nano-level optical antenna placed on an LED surface (for example, a sapphire substrate).

The photonic crystal, subwavelength diffuser and/or supersurface in a nanostructured layer can be: pure plasma, which is composed of metal nanoparticles; or metal dielectric, which is composed of metal and dielectric nanoparticles ; Or pure dielectric, which is composed of dielectric nanoparticles, usually high refractive index dielectric. Top-down or bottom-up manufacturing methods can be used to manufacture photonic crystals and/or metasurfaces in a nanostructured layer, and self-assembly of nanoparticles can be used to provide advantages in manufacturing and scalability. Photonic crystals can be manufactured for one, two or three dimensions. One-dimensional photonic crystals can be composed of layers deposited or adhered together. Two-dimensional photonic crystals can be made by photolithography or by drilling holes in a suitable substrate. Three-dimensional photonic crystal manufacturing methods include drilling holes at different angles, stacking multiple 2D layers on top of each other, direct laser writing, or for example, prompting the spheres to self-assemble in a matrix and dissolve the spheres. The photonic crystals in the nanostructure layer and/or the supramolecules in the supersurface can be held together by different technologies including but not limited to molecular linkers, DNA and the like. Alternatively, they can be manufactured by top-down manufacturing techniques (such as nanoimprint lithography, nanosphere lithography, or the like) and individual supramolecules released using exfoliation techniques. A nanostructure layer can be encapsulated by a dielectric such as silica or alumina to prevent the degradation of supramolecular properties over time.

Reveal the design and optimization for using a nanostructured layer to redirect light in the LED. By way of example and in order to provide a specific description, a flip chip of a chip-scale package (CSP) LED with a sapphire substrate is described, and the principles and teachings herein can be applied to any applicable LED design. A sapphire-based CSP emitter with a smooth light escape surface (LES) allows the deposition of a nanostructured layer so that light emitted by an active layer of the LED is incident on the nanostructured layer via the sapphire substrate.

According to the subject disclosed in this article, a nanostructured layer can increase incidence on the nanostructured layer by turning incident light at a higher angle with respect to the normal (for example, from less than 10 degrees to greater than 90 degrees) One of the incident angles of the beam increases the color uniformity. Alternatively or in addition, the nanostructure layer can increase the color uniformity by allowing light greater than a cut-off angle to pass through the nanostructure layer, so that it is incident on the nanostructure layer only at an angle that is more likely to increase the light path length The light passes through the nanostructure layer.

FIG. 1A shows an LED device 100 which includes a nanostructure layer 110 on an LED device including an epitaxial growth semiconductor layer 130 and a substrate 120. The epitaxial growth semiconductor layer 130 may include a first contact 137 and a second contact 138 separated by a gap 133. The gap 133 may be an air gap or may be filled with a dielectric material. A p-type layer 134 can be close to an active layer 135 and an n-type layer 139. The active layer 135 may be configured to emit light away from the contacts 137 and 138 so that the light beam emitted from the active layer 135 is emitted toward the substrate 120 generally. To facilitate the understanding of the present invention, the LED device 100 is presented in a simplified form, and those skilled in the related art will understand other elements included in an LED.

The epitaxial growth semiconductor layer 130 may be formed of any suitable material that is configured to emit photons when excited, including sapphire, SiC, GaN, polysilicon oxide, and more specifically, may be formed of any of the following: Group III-V Semiconductors, including but not limited to AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb; Group II-VI semiconductors, including but not limited to ZnS, ZnSe, CdSe, CdTe; Group IV Semiconductors include but are not limited to Ge, Si, SiC; and their mixtures or alloys. These exemplary materials may have a refractive index ranging from about 2.4 to about 4.1 at the typical emission wavelength of the LED in which they are present.

For example, aluminum nitride (AlN) can be used and it is a wide band gap (6.01 eV to 6.05 eV at room temperature) material. AlN may have a refractive index of about 1.9 to 2.2 (for example, 2.165 at 632.8 nm). Group III nitride semiconductors such as GaN may have a refractive index of about 2.4 at 500 nm, and group III phosphide semiconductors such as InGaP may have a refractive index of about 3.7 at 600 nm. An exemplary gallium nitride (GaN) layer may take the form of a pGaN layer. As those skilled in the related art will understand, GaN is often used as a binary III/V direct band gap semiconductor in light-emitting diodes. GaN can have a crystal structure with a wide band gap of 3.4 eV, which makes the material ideal for applications in optoelectronics, high-power, and high-frequency devices. GaN can be doped with silicon (Si) or oxygen to produce an n-type GaN and doped with magnesium (Mg) to produce a p-type GaN as used in the example of the present invention. The active layer 135 is a region in which light is emitted when electroluminescence occurs. The contacts 137 and/or 138 coupled to the LED device 100 may be formed of solder such as AuSn, AuGa, AuSi, or SAC solder.

As shown in FIG. 1A, the substrate 120 may be positioned between the semiconductor layer 130 and the nanostructure layer 110. The substrate may be a CSP emitter with a smooth LES that realizes the deposition of the nanostructure layer 110. The substrate 120 may include sapphire (which is also known as alumina of corundum (Al ₂ O ₃ )), and may exhibit properties including being very hard, strong, easy to machine, a good electrical insulator, and an excellent thermal conductor. Sapphire is usually transparent when produced synthetically, where the blue color in sapphire (and the red color in ruby of another form of corundum) comes from impurities in the crystal lattice. In other LEDs, gallium nitride (GaN) can be used to replace sapphire. The semiconductor layer 130 may be in a region where light is emitted when electroluminescence occurs.

As shown in FIG. 1A, the sidewall of the substrate 120 may be covered by the sidewall material 140. The sidewall material 140 can also cover one or more layers of the semiconductor layer 130, so that the same sidewall material 140 covers the substrate 120 and the semiconductor layer 130 or a material different from the semiconductor layer 130 can cover the sidewall of the substrate 120. The sidewall material 140 can be any suitable reflective or scattering material. According to an embodiment, the sidewall material 140 may be a distributed Bragg reflector (DBR).

The nanostructure layer 110 may include photonic materials incorporated into photonic crystals and/or metasurfaces that may include supramolecular and/or nano antennas, so that the maximum dimension of a supramolecular or nano antenna is less than 1000 nm. The nano antenna can be implemented as a nanoparticle array positioned in one of the nanostructure layers, as further disclosed herein. Nano antennas can be configured in periodic or non-periodic patterns, as further disclosed herein. Similar to chemical molecules composed of atoms, a supersurface is composed of supramolecules, where the supramolecules combine and interact to give the supersurface unique optical properties. The size of individual metasurfaces can be sub-wavelength or can be formed in the same order of wavelength.

The nanostructure layer 110 may also include nano antennas distributed throughout a bulk dielectric medium. The size of the nano antenna can be a sub-wavelength on the order of the wavelength.

As disclosed herein, in order to promote a longer light path of light traversing the wavelength conversion layer 102, a nanostructure layer 110 can produce a corner filter that transmits light at an angle greater than a corner cut-off angle and Radiation below the cutoff angle relative to the normal reflection angle. Therefore, the light beam incident on the nanostructure layer 110 only at a high angle (for example, illegal or close to normal) traverses the nanostructure layer 110. In view of the high angle, the light path of these light beams is longer than the light beams that, for example, would otherwise be incident on the wavelength conversion layer 102 at a lower (eg, at or near normal) angle.

As disclosed herein, the light beam incident on the nanostructure layer 110 of FIG. 1A can be reflected back into the substrate 120, so that the reflected light beam is incident on the sidewall material 140 and/or positioned below the active layer 135 and away from the surface of the substrate 120 On a back reflector 125 on the surface of the nanostructure layer 110. The back reflector 125 may be a plasma layer including flat metal mirrors, a distributed Bragg reflector (DBR), and/or other known LED reflectors. The back reflector 125 is designed to re-reflect the light beam reflected back into the substrate 120. The back reflector 125 can reflect the light beam before or after the light beam bounces back from the sidewall material 140 or can reflect the light beam directly reflected by the nanostructure layer 110.

Figure 1B shows an example of light redirection through a nanostructured layer. The LED device 111A is shown to have a substrate 120A and a wavelength conversion layer 102A. The light beams 112A and 113A traverse the substrate 120A and are incident on the wavelength conversion layer 102A at angles θ _1A and θ _2A , respectively. According to the disclosed subject matter, the LED device 111B is shown to have a substrate 120B, a wavelength conversion layer 102B, and a nanostructure layer 110B. The beams 112B and 113B traverse the substrate 120B with the same optical properties (eg, angle, frequency, direction) as the beams 112A and 113A when traversing the substrate 120A similar to the substrate 120B or the same as the substrate 120B. The light beams 112B and 113B are incident on the wavelength conversion layer 102B after traversing the nanostructure layer 110B. As shown, the light beams 112B and 113B are deflected within the nanostructure layer 110B so that they are incident on the wavelength conversion layer 102B at angles θ _1B and θ _2B , respectively. It will be noted that the angles Θ _1B and Θ _{2B are} greater than the angles Θ _{1 A} and Θ _{2 A} relative to the normal. For the sake of clarity, the nanostructured layer 110B turns the light beam incident on the nanostructured layer 110B so that it enters the wavelength at an angle greater than that of the nanostructured layer 110B without turning the light beam (ie, an example of the wavelength conversion layer 102A) Conversion layer 102B. Therefore, the path length of the light emitted through the wavelength conversion layer 102B is greater than the path length of the light emitted through the wavelength conversion layer 102A, and therefore, the light beams 112B and 113B are more likely to collide with the particles in the wavelength conversion layer 102B, thereby effectively increasing Conversion opportunities to provide color uniformity.

According to an embodiment, as disclosed herein, the nanostructure layer 110 of FIG. 1A can reflect the light beam incident on the nanostructure layer 110 at an angle less than a cut-off angle. An exemplary visual representation of this phenomenon is shown by light beams 122 and 123 in FIG. 1C. The light beams 122 and 123 may traverse the substrate 120 and be incident on the nanostructure layer 121. The nanostructure layer 121 can be configured so that light beams incident at an angle lower than a given cutoff angle are reflected back and light beams higher than the cutoff angle are transmitted through the nanostructure layer (for example, into a wavelength conversion layer) . Beam 122 may be lower than a cut-off angles (i.e., closer to normal) angle of incidence Θ ₃ is an incident angle such that a nanostructure layer reflected beam 122, such as a display. Beam 123 may be higher than the cutoff angle (i.e., further away from the normal) one angle of incidence Θ ₄ is incident on the nanostructure layer 121 and layer 121 may traverse nano structures, such as impressions. According to the disclosed subject matter, the light beam 123 can undergo light turning within the nanostructure layer 121. As disclosed herein, the light beam reflected back into the substrate 120 can experience one or more bounces within the substrate and/or on a back reflector, so that it can be reflected into the substrate 120 by the nanostructure layer 121 After that, it is incident on the nanostructure layer 121 for the second time. A light beam reflected by the nanostructure layer 121 into the substrate at a first time may experience one or more bounces within the substrate (for example, at the sidewall material, the back reflector, etc.) and may be returned after the first time It is incident on the nanostructure layer 121 for a second time. The incident angle of the light beam at the second time can be higher than the cut-off angle, and therefore, the light beam can pass through the nanostructure layer 121.

FIG. 1D shows a graph of φ average transmission 127 versus angle from a nanostructure layer that interacts with the exemplary light beam of nanostructure layer 121 as described for FIG. 1C. As shown, the configuration of the nanostructure layer 121 achieves a transmission or close to a transmission after a cut-off angle of approximately 45 degrees and does not allow transmission (for example, reflected beams) before the cut-off angle.

FIG. 1E shows an exemplary process 1400 of beam transmission through the substrate 120 and the nanostructure layer 110 of FIG. 1A (note that this process can also be applied to the nanostructure layer 121 of FIG. 1C and FIG. 1D). In step 1410, a first beam may be incident on the nanostructure layer 110 after traversing the substrate 120. The first light beam can be incident at an angle lower than the cut-off angle of the nanostructure layer 110. In step 1420, the first light beam may be reflected back into the substrate 120 at an angle lower than the cut-off angle based on the interaction with the nanostructure layer 110. In step 1430, a second light beam can be incident on the nanostructure layer 110 through the substrate 120. The second light beam can be incident at an angle higher than the cut-off angle of the nanostructure layer 110. In step 1440, the second light beam may be emitted through the nanostructure layer 110 at an angle higher than the cut-off angle based on its interaction with the nanostructure layer 110. According to an embodiment, as discussed herein, the first light beam may bounce off one or more internal surfaces of the substrate, sidewall material, and/or back reflector and then may be incident on the nanostructure at an angle higher than the cut-off angle On layer 110. Then, the first light beam can be emitted through the nanostructure layer 110 based on the incident angle higher than the cut-off angle.

This article will further discuss nanostructure layer configuration.

Figures 1F to 1H show different configurations of the nanostructure layers 110C, 110D, and 110E according to the subject matter herein. 1F shows a substrate 131, an adhesive layer 136, and a wavelength conversion layer 132. A nanostructure layer 110C is disposed between a first surface and a second surface of the wavelength conversion layer 132 in the wavelength conversion layer 132 so that the first surface and the second surface are flat relative to the substrate 131. FIG. 1G shows a substrate 131, an adhesive layer 136, and a wavelength conversion layer 132. A nanostructure layer 110D is disposed on a surface of the wavelength conversion layer 132 which is close to the substrate 131. FIG. 1G shows a substrate 131, an adhesive layer 136, and a wavelength conversion layer 132. A nanostructure layer 110E is disposed between the substrate 131 and the wavelength conversion layer 132 so that it is disposed in the adhesive layer 136.

As disclosed herein, the photonic nanostructure layer is structured so that it transmits radiation incident on a wavelength conversion layer after bending the angle of light toward a selected direction (for example, to an angle larger than the incident angle). For example, for an application with a ceramic phosphor, light normally incident on a nanostructure layer can be bent to a larger deflection angle in the phosphor layer with respect to the normal. This leads to an increase in the light path length of this light, which results in increased conversion and improvement in color mixing and color uniformity. The deflection angle of the nanostructure layer and the distribution of the nanostructures within the nanostructure layer can be selected to optimize color mixing and color uniformity, as disclosed in this article.

According to a Huygens metasurface configuration, a nanostructure layer may include nano cylinders, nano cones, or nano cubes arranged in a hexagonal or rectangular lattice. The lattice period can be sub-wavelength or greater than the wavelength. These nanostructures can be selected to satisfy the first Kok condition, so that the magnetic and electric dipole radiation is cancelled in the backward direction, resulting in a large forward scattering. For nano antennas containing a vertical dimer and/or coaxial dimer, interference modes can be provided in the respective supramolecules, which use structural parameters to provide better control over the scattering modes.

Figure 1I shows various cross-sections of some different possible nano antennas. The nano antenna can be formed by nano cylinders 191, nano cones 192, or nano cones 193 and 195 with vertical or coaxial dimers arranged in a hexagonal or rectangular lattice. The lattice period can be sub-wavelength or greater than the wavelength. Nano antennas can be Huygens supramolecular and/or support waveguide mode. Each photonic crystal or metasurface can exhibit a certain amount of beam bending properties, so that the incident beam can be shaped into a desired angular distribution.

As an example of an alternative configuration, FIG. 1K shows a sub-wavelength grating formed by asymmetric diffusers 167 and 172. The asymmetric diffuser 168 includes two nano-cylinders 164 and 166 with a height H on a substrate 162. As shown, the diffuser 168 is asymmetric so that the nano-cylinders 165 and 166 are not the same size/shape. The array of diffusers 168 can generate a nano-scattering layer so that the array contains multiple copies of diffusers 168. The diffuser 172 is an L-shaped diffuser, wherein one side of the diffuser 172 is larger than the other side of the diffuser 172. The array of diffusers 168 can generate a nano-scattering layer such that the array includes multiple copies of diffusers 168 and/or 172. These sub-wavelength diffusers can scatter the normal incident light to a large tilt angle. Asymmetric nanostructures (e.g., 168, 172) can be selected to be arranged in a two-dimensional grating. The design and placement of these nanostructures can be aimed at achieving the best possible color mixing and color uniformity.

In addition, it is possible to set up a configuration of the nano antenna at a given cut-off angle, so that the light incident above the cut-off angle passes through the nano-antenna and therefore the nanostructure layer, and the light incident below the cut-off angle does not pass through or Reflected back.

Nano antennas can be formed or arranged as a single nanophotonic structure, so that the same nano antenna is repeated multiple times to form a nanostructure layer. Alternatively or in addition, the nano antennas may be formed or arranged in a multi-nano structured material such that a nano antenna array is repeated multiple times to form a nano structure layer. FIG. 1J shows an exemplary multi-nano structure material 1300. As shown, the multi-nano structure material 1300 includes nano-cylinders 1301 and 1302, so that different nano-cylinders 1301 and 1302 have one or more different properties when compared with each other. As a visual example, as shown in FIG. 1J, the volume of the nano-cylinder 1301 is smaller than that of the nano-cylinder 1302. These poly-nanometer structures can be arranged such that a nano-structure layer 110 includes multiple iterations of the poly-nanometer structure material 1300. Each small multi-nanostructured material 1300 of a nanostructure layer 110 can provide beam bending to the light incident on the nanostructure layer 110. By appropriately placing a large number of different nano-cylinders 1301 with different beam bending properties in a multi-nano-structured material 1300 in the nano-structure layer 110, the light incident on the nano-structure layer 110 can be shaped To show a certain amount of beam bending properties or obtain a predetermined or better angular distribution. An optimizer can select the design and placement in the nanostructure layer 110 of FIG. 1A to obtain the best possible flux from the LED device 100 of FIG. 1A.

The design of the photonic crystal and/or metasurface can be indicated by the required beam bending or angular distribution, and the placement of the photonic crystal and/or metasurface can be determined based on an optimizer to obtain the best possible color mixing and color uniformity.

1A again, the side reflector 140, the back reflector 125, or the side reflector 140 and the back reflector 125 may be designed to further enhance the output to the nanostructure layer 110 through the nanostructure layer 110 at a desired increase (eg, tilt) angle The non-specular reflection nanostructure layer of the directional light in the wavelength conversion layer 102.

For example, the side reflector 140 and/or the back reflector 125 may be nanostructured layers that are designed so that compared with a specular reflector, they increase by a desired amount (for example, large ) The fraction of light rays incident on the nanostructure layer 110 directly reflected to the nanostructure layer 110 in the incident angle range or indirectly reflected to the nanostructure layer 110 (via one or more additional reflections) in the desired incident angle range. The desired incident angle range on the nanostructure layer 110 may be, for example, an incident angle greater than a cut-off angle as described above. These nano-structure side reflectors and back reflectors can be combined with each other depending on the situation.

The side reflector 140 and the back reflector 125 as just described can take the form of a nano-structured photonic layer designed to divert angular radiation. By way of non-limiting example only, this nano-structure side or back reflector may include asymmetric scattering elements (also referred to herein as nano-antennas), a photonic crystal, a metamaterial, a metasurface, or a subwavelength grating, or a combination thereof And other composition. The main function of this nanostructure side or back reflector is to reflect the radiation incident on it from a given angular range to a selected angular range. This limited angle range can be selected to direct as much light as possible from the rear surface or side of the LED toward the nanostructure layer 110 according to the desired incident angle.

Such a nanostructured back or side reflector may include scattering elements formed or arranged as unit cells. Each unit cell can provide beam bending to the light incident on the side reflector. By appropriately arranging a large number of different unit cells with different beam bending properties, the light can be shaped into a desired angular distribution.

In this nanostructure side or back reflector, the reflected beam bender (unit cell) can be configured as a periodic two-dimensional pattern or grating, for example, and can be encapsulated or otherwise contain one or more scattering elements The background material is formed and positioned adjacent to the substrate 120. A plurality of scattering elements can be surrounded by background material. A specular reflector can be adjacent to the background material at the distal end of the substrate 120. Asymmetric scattering can be achieved, for example, by using an asymmetric scattering element designed to connect the reflected field from the specular reflector to the scattering field from the scattering element. The interference between these fields causes light to scatter in a specific direction. The disposition of the scattering element can produce a spatial gradient of phase.

A unit cell of a periodic array of beam benders in a nanostructure side reflector can be rectangular in size and include a series of layers, including a specular reflector, one or more scattering elements, and as described above Background material. The periodicity can be centered on a mid-wavelength used, such as, for example, the peak wavelength emitted by the LED (e.g., 450 nm). In the unit cell, one or more scattering elements may be positioned adjacent to the substrate layer 120 at the distal end of the specular reflector and/or one or more scattering elements may be in contact or close contact with the specular reflector.

The scattering element can have any suitable height and width and can be formed of silicon (Si) or titanium oxide (TiO ₂ ) or a combination thereof, for example. The background material may be a low refractive index material, such as, for example, magnesium fluoride (MgF ₂ ). For example, the specular reflector (if present) can be a metal mirror (for example, a gold or silver mirror), a dielectric mirror, or a Bragg reflector.

The scattering element can take the form of any of the scattering elements described herein. For example, a scattering element may include a single light diffuser (a single dipole), or an array of light diffusers (dipole) may be configured similar to a Yagi antenna.

A scattering element can be designed as two interfering Huygens superatoms. The scattering element can be selected to meet the first Kirk condition, so that the magnetic and electric dipole radiation cancels out in the backward direction, resulting in a large forward scattering, which is called a Huygens superatom. A scattering element can be formed as a two-dimensional diffuser (such as, for example, a grating) or a three-dimensional scattering. An exemplary three-dimensional scattering can be a nano-cylinder. Other geometric diffusers can also be used, including, for example, L-shaped diffusers.

The scattering element can be formed by, for example, a nano cylinder, a nano cone, or a nano cube arranged in a hexagon or a rectangular lattice. The lattice period can be sub-wavelength or greater than the wavelength. In the case of a nanocylinder vertical dimer and coaxial dimer, the interference mode in the superatom or nano antenna uses structural parameters to provide additional control over the scattering mode.

The scattering element can also be formed of a photonic metamaterial (PM) (also called an optical metamaterial, which is an electromagnetic metamaterial that interacts with light and covers one of terahertz (THz), infrared (IR) or visible wavelengths). The material adopts a periodic honeycomb structure. Subwavelength periodicity distinguishes photonic metamaterials from photonic band gaps or photonic crystal structures. Cells are on a scale larger than atoms and far smaller than the wavelength of radiation, and are on the order of nanometers. In metamaterials, cells play the role of atoms in a material that is uniform on a scale larger than the cell, thereby creating an effective medium model.

FIG. 2A is a diagram of an LED device 200 in an exemplary embodiment. The LED device 200 may include one or more epitaxial layers 202, an active layer 204, and a substrate 206. In other embodiments, an LED device may include a wavelength converter layer and/or primary optics. As shown in FIG. 2A, the active layer 204 may be adjacent to the substrate 206 and emit light when excited. The epitaxial layer 202 may be close to the active layer 204 and/or one or more intermediate layers may be between the active layer 204 and the epitaxial layer 202. The substrate 206 may be close to the active layer 204 and/or one or more intermediate layers may be between the active layer 204 and the substrate 206. The active layer 204 emits light into the substrate 206. A nanostructure layer can be placed on the substrate 206, so that the light incident on the nanostructure layer is bent by the nanostructure layer or filtered by the nanostructure layer, so that only the light beam with a cut-off angle higher than the normal is transmitted through Launch of nanostructure layer.

Figure 2B shows a cross-sectional view of an illumination system 220 including an LED array 210 having pixels 201A, 201B, and 201C. The LED array 210 includes pixels 201A, 201B, and 201C, each of which includes a respective substrate 206B, an active layer 204B, and an epitaxial layer 202B. The pixels 201A, 201B, and 201C in the LED array 210 can be formed using array segmentation or alternatively using pick-and-place technology and can emit light of different peak wavelengths such as red, green, and blue, for example. The space 203 displayed between the one or more pixels 201A, 201B, and 201C may include an air gap or may be filled with a material such as a metal material that may be a contact (eg, n-contact). According to some embodiments, secondary optics such as one or more lenses and/or one or more waveguides may be provided.

The LED device 200 or the pixels 201A, 201B, and 201C can be single-wavelength emitters and can be powered individually or via an array. The LED device 200 or the pixels 201A, 201B, and 201C may be part of a lighting system that includes one or more electronic boards, power modules, sensors, connectivity and control modules, LED attachment areas, or the like. Pixels in an array can be powered based on signals from different channels and their operations can be determined by a microcontroller.

FIG. 3 shows an exemplary system 550 including an application platform 560 and LED systems 552 and 556. The LED system 552 generates a light beam 561 shown between arrows 561a and 561b. The LED system 556 can generate a light beam 562 between the arrows 562a and 562b. As an exemplary embodiment, the LED systems 552 and 556 can be part of a car and can emit infrared (IR) optical communication beams so that one of the paths of the beams 561 and/or 562 can receive communications from the car. . In an exemplary embodiment, the system 550 may be a camera flash system, a mobile phone, indoor residential or commercial lighting, outdoor lights (such as street lighting), an automobile, a medical device, an AR/VR device, and a robotic device.

The application platform 560 can provide power to the LED system 552 and/or 556 via a power bus via line 565 or other suitable input, as discussed herein. In addition, the application platform 560 can provide input signals for the operation of the LED system 552 and the LED system 556 via the line 565. The input can be based on a user input/preference, a sensed reading, a preprogrammed or autonomously determined output or Similar. One or more sensors may be inside or outside the housing of the application platform 560.

In various embodiments, the application platform 560 sensor and/or the LED system 552 and/or 556 sensor can collect data, such as visual data (eg, LIDAR data, IR data, data collected through a camera, etc.) , Audio data, distance-based data, mobile data, environmental data, or the like or a combination thereof. Data can be collected based on, for example, the LED systems 552 and/or 556 emitting an optical signal (such as an IR signal) and collecting data based on the emitted optical signal. Data can be collected by a component that is different from the component that emits optical signals for data collection. To continue the example, the sensing device can be positioned on a car and can use a vertical cavity surface emitting laser (VCSEL) to emit a beam. One or more sensors can sense a response to one of the emitted light beam or any other applicable input.

Although the features and elements are described above in specific combinations, those skilled in the art will appreciate that each feature or element can be used alone or in any combination with or without other features and elements. In addition, the methods described herein can be implemented in a computer program, software, or firmware incorporated in a computer-readable medium to be executed by a computer or processor. Examples of computer-readable media include electronic signals (transmitted via wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, a read-only memory (ROM), a random access memory (RAM), a register, a cache memory, a semiconductor memory device, magnetic media (such as built-in Hard disks and removable disks), magneto-optical media, and optical media (such as CD-ROM discs and digital versatile discs (DVD)).

100: Light-emitting diode (LED) device 102: Wavelength conversion layer 102A: Wavelength conversion layer 102B: Wavelength conversion layer 110: Nano structure layer 110B: Nano structure layer 110C: Nano structure layer 110D: Nano structure layer 110E: Nano structure layer 111A: Light Emitting Diode (LED) device 111B: Light Emitting Diode (LED) device 112A: beam 112B: beam 113A: beam 113B: beam 120: substrate 120A: substrate 120B: substrate 121: Nano structure layer 122: beam 123: beam 125: back reflector 127: φ average transmission 130: epitaxial growth of semiconductor layer 131: Substrate 132: Wavelength conversion layer 133: Gap 134: p-type layer 135: Action layer 136: Adhesive layer 137: first contact 138: second contact 139: n-type layer 140: sidewall material 162: Substrate 164: Nano cylinder 166: Nano Cylinder 168: Asymmetric diffuser 172: Asymmetric diffuser 191: Nano cylinder 192: Nano cone 193: Nano cone 195: Nano cone 200: Light-emitting diode (LED) device 201A: pixel 201B: pixel 201C: Pixel 202: epitaxial layer 202B: epitaxial layer 203: Space 204: Action layer 204B: active layer 206: substrate 206B: substrate 210: Light Emitting Diode (LED) Array 220: lighting system 550: System 552: Light Emitting Diode (LED) System 556: Light Emitting Diode (LED) System 560: Application Platform 561: beam 561a: Arrow 561b: Arrow 562: beam 562a: Arrow 562b: Arrow 565: line 1301: Nano cylinder 1302: Nano cylinder 1400: Process 1410: step 1420: step 1430: steps 1440: step

A more detailed understanding can be obtained from the following description given by examples in conjunction with the accompanying drawings, in which:

Figure 1A is a schematic diagram of a light emitting device with a nanostructure layer;

Figure 1B shows a diagram of light emission with and without a nanostructure layer;

Figure 1C shows a diagram of light emission with a nanostructure layer;

Figure 1D is a graph showing the transmission that changes according to the angle;

Figure 1E is a flow chart of light emission with a nanostructure layer;

Figure 1F has a structure of one nanostructure layer;

Figure 1G shows another structure with a nanostructure layer;

Figure 1H is another structure with a nanostructure layer;

Figure 1I is a schematic diagram of different nano antennas;

Figure 1J is a multi-nano structure material array;

Figure 1K is another diagram of different nano antennas;

Figure 2A shows a diagram of a light emitting diode (LED) device;

Figure 2B shows a diagram of multiple LED devices; and

Figure 3 is a diagram of an exemplary application system.

100: Light-emitting diode (LED) device

102: Wavelength conversion layer

110: Nano structure layer

120: substrate

125: back reflector

130: epitaxial growth of semiconductor layer

133: Gap

134: p-type layer

135: Action layer

137: first contact

138: second contact

139: n-type layer

140: sidewall material

Claims (36)

A light emitting device, which includes: A semiconductor diode structure; A substrate that is transparent to the light emitted by the semiconductor diode structure and includes a top surface, a relatively positioned bottom surface, and a side surface connecting the top surface and the bottom surface, the bottom surface being disposed on the semiconductor diode On or adjacent to the semiconductor diode structure; A wavelength conversion structure including a top surface and a relatively positioned bottom surface disposed on or adjacent to the top surface of the substrate; and A nanostructure metasurface, which includes a plurality of nano antennas, the metasurface is positioned between the top surface of the substrate and the top surface of the wavelength conversion structure and is configured to: Transmitting the light rays emitted by the semiconductor diode structure and incident on the metasurface from the substrate side of the metasurface to the wavelength converter at an angle greater than the angle of incidence on the metasurface; or Reflects the light rays emitted by the semiconductor diode structure and incident on the metasurface from the substrate side of the metasurface at an angle less than or equal to a cutoff angle, and will be emitted by the semiconductor diode structure at an angle greater than One of the cut-off angles is that the light rays incident on the metasurface from the substrate side of the metasurface are transmitted into the wavelength converter; or Reflects the light rays emitted by the semiconductor diode structure and incident on the metasurface from the substrate side of the metasurface at an angle less than or equal to a cutoff angle, and is greater than the incident on the metasurface An angle of the angle transmits the light rays emitted from the semiconductor diode structure and incident on the metasurface from the substrate side of the metasurface at an angle greater than the cut-off angle to the wavelength converter. The light-emitting device of claim 1, wherein the supersurface is disposed on or adjacent to the bottom surface of the wavelength converter. The light-emitting device of claim 1, wherein the metasurface is arranged in the wavelength converter. The light-emitting device of claim 1, wherein the nano-antennas are arranged in a periodic lattice. The light emitting device of claim 1, wherein each of the nano antennas has a maximum size smaller than a wavelength of the light emitted by the semiconductor diode structure. Such as the light-emitting device of claim 1, wherein at least one nano antenna is asymmetrical. Such as the light-emitting device of claim 1, wherein at least one nano antenna includes two or more light scattering objects. Such as the light-emitting device of claim 7, wherein the light scattering objects are symmetrical objects. Such as the light emitting device of claim 8, wherein the light scattering objects are arranged asymmetrically. The light-emitting device of claim 1, wherein the metasurface is configured to be emitted from the semiconductor diode structure at an angle greater than its angle of incidence on the metasurface and incident on the substrate side of the metasurface The light rays on the metasurface are transmitted to the wavelength converter. The light-emitting device of claim 10, wherein the metasurface is disposed on or adjacent to the bottom surface of the wavelength converter. The light-emitting device of claim 10, wherein the metasurface is arranged in the wavelength converter. Such as the light-emitting device of claim 10, wherein the nano-antennas are arranged in a periodic lattice. The light emitting device of claim 10, wherein each of the nano-antennas has a maximum size smaller than a wavelength of the light emitted by the semiconductor diode structure. Such as the light emitting device of claim 10, wherein at least one nano antenna is asymmetrical. Such as the light-emitting device of claim 10, wherein at least one nanometer antenna includes two or more light scattering objects. Such as the light-emitting device of claim 16, wherein the light scattering objects are symmetrical objects. Such as the light emitting device of claim 17, wherein the light scattering objects are arranged asymmetrically. The light emitting device of claim 1, wherein the metasurface is configured to reflect emission from the semiconductor diode structure and incident on the metasurface from the substrate side of the metasurface at an angle less than or equal to a cut-off angle The light rays emitted by the semiconductor diode structure and incident on the metasurface from the substrate side of the metasurface at an angle greater than the cut-off angle are transmitted to the wavelength converter. The light emitting device of claim 19, wherein the metasurface is disposed on or adjacent to the bottom surface of the wavelength converter. The light emitting device of claim 19, wherein the metasurface is arranged in the wavelength converter. The light-emitting device of claim 19, wherein the nano-antennas are arranged in a periodic lattice. The light emitting device of claim 19, wherein each of the nano antennas has a maximum size smaller than a wavelength of the light emitted by the semiconductor diode structure. Such as the light-emitting device of claim 19, wherein at least one nano-antenna is asymmetrical. Such as the light emitting device of claim 19, wherein at least one nano antenna includes two or more light scattering objects. Such as the light-emitting device of claim 25, wherein the light scattering objects are symmetrical objects. Such as the light emitting device of claim 26, wherein the light scattering objects are arranged asymmetrically. The light emitting device of claim 1, wherein the metasurface is configured to reflect emission from the semiconductor diode structure and incident on the metasurface from the substrate side of the metasurface at an angle less than or equal to a cut-off angle Ray, and will be emitted from the semiconductor diode structure at an angle greater than its incident angle on the metasurface and incident on the metasurface from the substrate side of the metasurface at an angle greater than the cut-off angle The light rays above are transmitted to the wavelength converter. The light emitting device of claim 28, wherein the supersurface is disposed on or adjacent to the bottom surface of the wavelength converter. The light emitting device of claim 28, wherein the metasurface is arranged in the wavelength converter. The light-emitting device of claim 28, wherein the nano-antennas are arranged in a periodic lattice. The light emitting device of claim 28, wherein each of the nano antennas has a maximum size smaller than a wavelength of the light emitted by the semiconductor diode structure. Such as the light-emitting device of claim 28, wherein at least one nano antenna is asymmetrical. Such as the light-emitting device of claim 28, wherein at least one nano antenna includes two or more light scattering objects. Such as the light emitting device of claim 34, wherein the light scattering objects are symmetrical objects. Such as the light emitting device of claim 35, wherein the light scattering objects are arranged asymmetrically.

Images