Micro light emitting diode, micro light emitting diode device, display and method thereof

Abstract

The invention relates to various aspects of a [mu]-LED or a [mu]-LED arrangement for augmented reality or light applications, in particular in the automotive field. The [mu]-LEDs are characterized by particularly small dimensions in the range of several [mu] m.

Description

[0001] This invention is a divisional application of the parent application, which is filed on January 29, 2020, with application number 202080023800.9 and invention title "Miniature Light Emitting Diode, Miniature Light Emitting Diode Device, Display and Method Thereof" (PCT International Application PCT / EP2020 / 052191 entered the Chinese National Phase).

[0002] This patent application claims priority to the following German patent applications: DE 10 2019 201114.4, dated January 29, 2019; DE 10 2019 111 766.6, dated May 7, 2019; DE 10 2019 112 124.8, dated May 9, 2019; DE 10 2019 116 313.7, dated June 14, 2019; DE 10 2019 131 506.9, dated November 21, 2019; DE 10 2019 118 251.4, dated July 5, 2019; DE 10 2019 118 082.1, dated July 4, 2019; and DE 10 2019, dated March 29, 2019. 108 260.9, DE 10 2019 on September 20, 2019 125 349.7, DE 10 2019 on May 13, 2019 112 490.5, DE 10 2019 on May 14, 2019 112 604.5, DE 10 2019 on May 14, 2019 112 609.6, DE 10 2019 on January 31, 2019 102 509.5, DE 10 2019 on June 7, 2019 115 479.0, DE 10 2019 on May 14, 2019 112 616.9, DE 10 2019 on May 23, 2019 113791.8, DE 10 2019 110 499.8 on April 23, 2019, DE 10 2019 110523.4 on April 23, 2019, DE 10 2019 130 934.4 on November 15, 2019, DE 10 2019 114321.7 on May 28, 2019, DE 10 2019 127 425.7 on October 11, 2019, DE 10 2019 112639.8 on May 14, 2019, DE 10 2019 112 605.3 on May 22, 2019 113636.9, DE 10 2019 103 365.9 on February 11, 2019, DE 10 2019 116312.9 on June 14, 2019, DE 10 2019 115 991.1 on June 12, 2019, DE 10 2019 125875.8 on September 25, 2019, DE 10 2019 127 424.9 on October 11, 2019, DE 10 2019 118085.6 on July 4, 2019, DE 10 2019 125 336 on September 20, 2019.5. DE 10 2019 113793.4 on May 23, 2019; DE 10 2019 110 500.5 on April 23, 2019; DE 10 2019 111 767.4 on May 7, 2019; DE 10 2019 121 672.9 on August 12, 2019; DE 10 2019 118 084.8 on July 4, 2019; DE 10 2019 113 768.3 on May 23, 2019; DE 10 2019 113 792.6 on May 23, 2019; DE 10 2019 110 on April 23, 2019. 497.1, DE 10 2019 114 442.6 dated May 29, 2019, DE 10 2019 129 209.3 dated October 29, 2019, DE 10 2019 130 821.6 dated November 14, 2019, and DE10 2019 130 866.6 dated November 15, 2019, the disclosures of which are incorporated herein by reference, and also claim Danish patent applications DK PA201970059, DK PA201970060, and DK, dated January 29, 2019. The patent claims priority to PA201970061, the disclosure of which is incorporated herein by reference, and also to U.S. patent application US 62 / 937,552, dated November 19, 2019, the disclosure of which is incorporated herein by reference. Technical Field

[0003] This invention relates to miniature light-emitting diodes, miniature light-emitting diode devices, and displays. Background Technology

[0004] The ongoing developments in the Internet of Things (IoT) and communications fields have opened doors to a variety of new applications and designs. These designs and applications offer greater effectiveness and efficiency for development, service, and manufacturing purposes.

[0005] One aspect of the new design involves augmented reality, or virtual reality. The general definition of “augmented reality” is: “an interactive experience of a real environment in which objects in the real world are extended by computer-generated perceptible information.”

[0006] Information is primarily conveyed through visualization, but not limited to visual perception. Sometimes, tactile or other sensory perceptions can be used to augment reality. In the case of visualization, the overlaid sensory visual information can be constructive—that is, supplementing the natural environment—or non-constructive, such as by covering a portion of the natural environment. In some applications, interaction with the overlaid sensory information may also occur in one or another manner. Thus, augmented reality enhances the user's continuous perception of the real environment.

[0007] In contrast, "virtual reality" replaces the user's real environment with a completely simulated one. In other words, while users can perceive the real world at least partially in an augmented reality environment, the environment in virtual reality is completely simulated and may differ significantly from reality.

[0008] Augmented reality (AR) can be used to improve natural environmental conditions, thereby enriching the user experience or supporting them in performing certain tasks. For example, users can use displays with AR capabilities to assist them in performing certain tasks. By overlaying information about real objects to provide clues to the user, it provides additional information, enabling them to act faster, safer, and more efficiently during manufacturing, repair tasks, or other services. In the medical field, AR technology can be used to guide and support doctors in diagnosing and treating patients. In development, engineers can directly experience their test results, making it easier to evaluate the outcomes. In the tourism or events industry, AR can provide users with additional information about attractions, history, and more. AR can also support learning activities or tasks. Summary of the Invention

[0009] The following introduction illustrates various aspects of μ (micro) displays in automotive and augmented reality applications. These aspects include devices, displays, controls, process techniques, and other suitable features for augmented reality and automotive applications. This includes aspects designed to generate light through indicators, displays, etc. Additionally, aspects of control circuitry, power supplies, and optical coupling outputs, light guiding, and light focusing are listed, along with applications of such devices, explained using various examples.

[0010] Because of the various limitations and challenges posed by the small size of the light-generating components, combining various aspects is not only advantageous but often necessary. For ease of handling, this disclosure is divided into several parts with similar topics. However, it should not be explicitly understood that features of one topic cannot be combined with other topics. Rather, aspects from different subject areas must be combined to create displays for augmented reality or other applications or in the automotive field.

[0011] To consider the following solutions, some terms and expressions should be explained to define common and shared understanding. For clarity, the listed terms are generally used herein. However, in individual cases, they may deviate from the intended interpretation, where such deviation is identifiable.

[0012] "Active Matrix Display"

[0013] The term "active matrix display" originally referred to liquid crystal screens containing a matrix of thin-film transistors controlled by LCD (liquid crystal display) pixels. Each individual pixel has a circuit with active components (mainly transistors) and power connections. However, this technology should not be limited to liquid crystals at present, but should specifically refer to the control of μ-LEDs (micro-light-emitting diodes) or μ displays.

[0014] "Active Matrix Carrier Substrate"

[0015] An "active matrix carrier substrate" or "active matrix backplane" refers to the driving device for the light-emitting diodes (LEDs) of a display with thin-film transistor (TFT) circuitry. Here, these circuits can be integrated into or applied to the backplane. The "active matrix carrier substrate" has one or more interface contacts that form an electrical connection with the μ-LED display structure. Therefore, the "active matrix carrier substrate" can be part of or carry an active matrix display.

[0016] "Active layer"

[0017] An active layer is a layer in an optoelectronic device or light-emitting diode (LED) where charge carriers recombine. In its simplest form, an active layer is characterized by regions of two adjacent semiconductor layers with different conductivity types. More complex active layers include quantum wells (see related description), multiple quantum wells, or other structures with additional properties. Structural and material systems can also be used to define the band gap in the active layer (see related description), which defines the wavelength and thus the color of light.

[0018] "Alvarez Lens Device"

[0019] The optical path of the video glasses can be adjusted by using Alvarez lens pairs. The adjustment optics include Alvarez lens devices, particularly rotatable variants with moiré lens devices. Here, beam deflection is determined by the first derivative of the individual phase plate morphologies, approximately z = ax² + by² + cx + dy + e for the radiation direction z and the transverse directions x and y, and is determined by the offset of the two phase plates arranged in pairs in the transverse directions x and y. For alternative designs, pivotable prisms are provided in the adjustment optics.

[0020] Augmented Reality (AR)

[0021] This is an interactive experience of a real-world environment, where the filmed project is located in the real world and enhanced by computer-generated perceptible information. Augmented reality is understood as a computer-aided extension of the perception of reality through such computer-generated perceptible information. This information can appeal to all human senses. However, augmented reality often refers only to the visual representation of information, i.e., images or videos with computer-generated additional information or virtual objects added through fade-in / overlay. Applications and explanations of how augmented reality works can be found in the introduction to the examples and below.

[0022] "car"

[0023] "Automotive" generally refers to motor vehicles or the automotive industry. Therefore, the term is intended to include this branch, but also all other industry branches, including microdisplays or general luminous indicators with very high resolution and μ-LEDs.

[0024] "band gap"

[0025] The energy gap between the valence band and conduction band of a solid is called the band gap, also known as the band gap or band exclusion zone. Its electrical and optical properties depend largely on the size of the band gap. The size of the band gap is usually expressed in electron volts (eV). The band gap is used to distinguish metals, semiconductors, and insulators. The band gap can be tuned (i.e., changed) by various measures such as spatial doping to detune the crystal structure or by altering the material system. Material systems with a so-called direct band gap, where the maximum value of the valence band and the minimum value of the conduction band are superimposed in momentum space, allow electron-hole pairs to recombine with emitted light.

[0026] Bragg photogate

[0027] A Bragg fiber optic grating is a special optical interference filter etched into an optical waveguide. Wavelengths within the filter bandwidth near λB are reflected. Various methods are used to generate periodic modulation of the refractive index within the fiber core of the waveguide. This creates regions with high and low refractive indices that reflect light of specific wavelengths (bandstop). The center wavelength of the filter bandwidth in a single-mode fiber is determined by the Bragg condition.

[0028] "Directionality"

[0029] Directivity, or directionality, is used to describe the radiation characteristics of μ-LEDs or other light-emitting components. High directionality corresponds to highly directional radiation or a low-radiation cone. Typically, the goal is to achieve a high level of directional radiation to minimize crosstalk between light and adjacent pixels. Consequently, the brightness of the light-emitting component varies depending on the viewing angle, thus differing from a Lambertian emitter.

[0030] Directionality can be altered, for example, by mechanical or other means on the side used for emission. Besides lenses, this includes photonic crystals or columnar structures (pillar structures) arranged on the emission surface of the pixelated array or, in particular, on an arrangement of μ-LEDs. These create a virtual bandgap that reduces or prevents the light vector from diffusing along the emission surface.

[0031] "Far field"

[0032] The terms near field and far field describe the spatial regions surrounding components that emit electromagnetic waves and have distinct characteristics. Typically, these spatial regions are divided into three areas: the reactive near field, the transition field, and the far field. In the far field, electromagnetic waves propagate as plane waves, independent of the radiating element.

[0033] "Screen window effect"

[0034] The screen-door effect (SDE) is a permanently visible image artifact in digital video projectors. The term describes an undesirable, technically relevant dark distance between individual pixels or their projected information, taking the form of a screen. This distance originates from the construction, as the conductive circuitry used for control runs between the individual LCD segments, where light is swallowed up and cannot reach the screen. If small photoelectric light-emitting devices are used, particularly μ-LEDs, or the distance between individual LEDs is too large, the low packing density produced when viewing a single LED can result in a visible difference in pixel areas between bright and dark spots. This so-called screen-door effect is particularly noticeable when viewed from a smaller distance, especially in applications such as VR (virtual reality) glasses. When the illumination differences within a pixel persist periodically across the entire matrix arrangement, the sub-pixel structure is often perceived and annoying. Therefore, the screen-door effect should be avoided as much as possible in automotive and augmented reality applications.

[0035] "Flip Chip"

[0036] Flip chip assembly is a method of fabrication and connection technology used to contact unpackaged semiconductor chips via contact bumps known as "bumps." With flip chip assembly, the chip can be directly mounted without additional interconnects, with its effective contact surface facing down (towards the substrate / circuit carrier) above the bumps. This results in a particularly small housing size and shorter conductor length. Therefore, flip chips are especially suitable for electronic semiconductor components that contact on their back side. Such components may also require special transfer techniques, such as using an auxiliary carrier. In the case of flip chips, the radiation direction is typically opposite to the side of the contact surface.

[0037] "trigger"

[0038] A flip-flop, also commonly known as a bistable switching stage or bistable switching element, is an electronic circuit with two stable output signal states. The current state depends not only on the currently available input signal but also on the state that existed prior to the point in time being considered. There is no time correlation, only event correlation. Due to its bistable nature, a flip-flop can store one bit of data indefinitely. However, unlike other types of memory, a voltage supply must always be guaranteed. Flip-flops are a fundamental component of sequential circuits and an essential part of digital technology, thus forming a basic element in many electronic circuits, from quartz clocks to microprocessors. In particular, as a basic one-bit memory, it is a fundamental element of the static memory module used in computers. Some embodiments may use different types of flip-flops or other buffer circuits to store state information. Their respective input and output signals are digital, meaning they alternate between logical "false" and logical "true". These values ​​are also referred to as "low" 0 and "high" 1.

[0039] Head-up display

[0040] A head-up display (HUD) is a display system or projection device in which a user maintains a certain head posture or gaze as information is projected into the user's field of view. HUDs are augmented reality systems. In some cases, HUDs incorporate sensors that determine the direction or orientation of the user's gaze in space.

[0041] Horizontal LED

[0042] In the case of horizontal LEDs, the electrical connection is located on the common side of the LED. This is typically the back side of the LED, away from the light-emitting surface. Therefore, horizontal LEDs have contacts formed only on the surface side.

[0043] "Interference Filter"

[0044] An interference color filter is an optical component that uses the interference effect to filter light in a frequency-dependent manner (i.e., in a color-dependent manner for visible light).

[0045] "Collimation"

[0046] In optics, collimation refers to the parallel direction of diverging rays. The associated lens is called a collimator or condenser. A collimated beam contains mostly parallel rays and therefore has minimal scattering during propagation. Its use in this sense relates to the scattering of light emitted from a light source. A collimated beam emitted from a surface is highly dependent on the angle of radiation. In other words, the radiance (unit power per unit angle of a projected light source area) of a collimated light source varies with increasing angle. Light can be collimated in various ways, such as by using a special lens placed in front of the light source. Therefore, collimated light can also be considered as light with a high degree of directional dependence.

[0047] "Converter Materials"

[0048] Converter materials are materials suitable for converting light of a first wavelength into light of a second wavelength, shorter than the second. These include various permanent inorganic and organic dyes as well as quantum dots. Converter materials can be applied and constructed in a variety of processes.

[0049] "Lambert Launcher"

[0050] The so-called Lambertian radiation characteristic is required in many applications. This means that the luminescent surface ideally has a uniform radiation density on its surface, resulting in a vertically circular distribution of radiation intensity. Since humans can only assess brightness with their eyes (brightness is the luminous equivalent of illuminance), such Lambertian materials appear equally bright regardless of the viewing direction. This uniform, angle-independent brightness can be an important quality factor, especially for curved and flexible display surfaces, which is sometimes difficult to achieve with currently available displays due to their structure and LED technology.

[0051] LEDs and μ-LEDs are similar to Lambertian emitters and emit light at a large spatial angle. Depending on the application, further steps can be taken to improve radiation characteristics, or greater directionality can be attempted (see related notes).

[0052] "Conductivity type"

[0053] The term "conductivity type" refers to the majority (n- or p-type) charge carriers in a given semiconductor material. That is, a semiconductor material doped with n (negative) type is considered to be of n conductivity type. Similarly, if a semiconductor material is n-type, then it is n-type doped. The term "active" region in a semiconductor refers to the boundary region between an n-type doped layer and a p (positive)-type doped layer. Radiative recombination of p-type and n-type charge carriers occurs in this region. In some embodiments, the active region is further constructed and includes, for example, a quantum well or quantum dot structure.

[0054] "Light field display"

[0055] A display technology that projects raster images directly onto the retina of the eye is called a Virtual Retinal Display (VNA) or Light Field Display. The user gains the impression of a canvas floating in front of them. Light Field Displays can be provided as glasses, projecting raster images directly onto the user's retina. Using a Virtual Retinal Display, an image is created within the user's eye through direct projection of the retina. Light Field Displays are augmented reality systems.

[0056] "Plate printing" or "photolithography"

[0057] Photolithography is one of the core methods in semiconductor and microsystems technology, used to manufacture integrated circuits and other products. In this process, the image of a photomask is transferred onto a photosensitive photoresist through exposure. Subsequently, the exposed areas of the photoresist are dissolved (or the unexposed areas can also be dissolved when the photoresist cures under light). This forms a lithographic mask, which can be further processed through chemical and physical processes, such as applying material to the open areas or etching recesses in the open areas. The remaining photoresist can then be removed.

[0058] “μ-LED”

[0059] μ-LEDs are optoelectronic devices with edge lengths less than 70 μm, particularly less than 20 μm, and especially in the range of 1 μm to 10 μm. Another range is between 10 and 30 μm. This results in a range of several hundred μm. 2 Up to tens of μm 2 The area of ​​a μ-LED is approximately 60 μm², with an edge length of approximately 8 μm. In some cases, the edge length of a μ-LED is 5 μm or less, resulting in a size less than 30 μm². For example, the typical height of such a μ-LED is between 1.5 μm and 10 μm.

[0060] Besides classic lighting applications, μ-LEDs are primarily used in displays. Here, μ-LEDs form pixels or subpixels and emit light of a specified color. Due to their small pixel size and high density at close range, μ-LEDs are also suitable for small, monolithic displays used in AR applications.

[0061] Due to the extremely small size of μ-LEDs, their production and processing are significantly more difficult compared to previous large LEDs. This also applies to other components such as contact lenses, packaging, and lenses. Some aspects feasible in large optoelectronic components cannot be achieved in μ-LEDs, or must be achieved in different ways. In this respect, μ-LEDs are therefore significantly different from traditional LEDs, i.e., light-emitting elements with an edge length of 200 μm or more.

[0062] μ-LED array

[0063] See Microdisplay

[0064] "Miniature display"

[0065] A microdisplay, or μ-LED array, is a matrix with a large number of pixels arranged in prescribed rows and columns. Functionally, a μ-LED array typically forms a matrix primarily composed of μ-LEDs of the same type and color. Therefore, it provides a larger surface area for illumination. On the other hand, the purpose of a μ-display is to transmit information, which often also necessitates different colors or positional control for each individual pixel or subpixel. A microdisplay can consist of multiple μ-LED arrays, formed together on a backplane or other carrier. However, μ-LED arrays can also be used to form microdisplays.

[0066] Each pixel is on the order of a few μm, similar to a μ-LED. Therefore, a μ-display with 1920×1080 pixels, each with a 5μm μ-LED, and directly adjacent pixels has an overall size of 10 mm². In other words, a microdisplay or μ-LED array is a small-scale device implemented using μ-LEDs.

[0067] Microdisplays or μ-LED arrays can be formed from a single, identical component. The μ-LEDs in a μ-LED array can be formed monolithically. Such microdisplays or μ-LED arrays are called monolithic μ-LED arrays or microdisplays.

[0068] Alternatively, both components can be formed by growing μ-LEDs individually on a substrate and then arranging them individually or in groups on a carrier using a so-called pick-and-place process, maintaining a certain distance between them. Such a microdisplay or μ-LED array is referred to as non-monolithic. In a non-monolithic microdisplay or μ-LED array, other distances between individual μ-LEDs are also possible. These distances can be flexibly chosen depending on the application and implementation. Therefore, such a microdisplay or μ-LED array can also be referred to as a pitch-extended component. In a pitch-extended microdisplay or μ-LED array, the μ-LEDs are arranged at greater distances when delivered to the carrier than they are on the growth substrate. In a non-monolithic microdisplay or μ-LED array, each individual pixel may each include a blue-emitting μ-LED, a green-emitting μ-LED, and a red-emitting μ-LED.

[0069] To leverage the advantages of both monolithic and non-monolithic μ-LED arrays within a single module, monolithic μ-LED arrays can be combined with non-monolithic μ-LED arrays in a microdisplay. This allows the microdisplay to be used for different functions or applications. Such a display is called a hybrid display.

[0070] "μ-LED nanopillars"

[0071] μ-LED nanopillars are typically a stack of semiconductor layers with an active layer, thus forming a μ-LED. The edge length of a μ-LED nanopillar is less than its height. For example, the edge length of a μ-LED nanopillar is approximately 10 nm to 300 nm, while the height of the device may be 200 nm to 1 μm or higher.

[0072] "μ column"

[0073] μ-pillars or pillars specifically refer to a geometric structure, particularly a rod or bar, or generally a slender, cylindrical structure. The spatial dimensions of manufactured μ-pillars range from μm to nm. Therefore, nanopillars are also included herein.

[0074] "Nanopillars"

[0075] In nanotechnology, nanopillars are a design concept for nanoscale objects. Each of them ranges in size from approximately 10 nm to 500 nm. They can be synthesized from metallic or semiconducting materials. The aspect ratio (length divided by width) is 3 to 5. Nanopillars are made through direct chemical synthesis. A combination of ligands acts as a shape control agent and attaches to different faces of the nanopillar with varying strengths. This allows for different designs of nanopillars with different growth rates to produce an elongated object. μLED nanopillars are such nanopillars.

[0076] Miniature LED

[0077] Its size ranges from 100μm to 750μm, especially in the range greater than 150μm.

[0078] Moiré effect and Moiré lens array

[0079] The moiré effect refers to the noticeably coarser gratings produced by the superposition of regular, finer gratings. The resulting pattern, resembling a pattern from interference, is a special case of aliasing caused by undersampling. In signal analysis, aliasing occurs when the signal being sampled contains frequency components higher than half the sampling frequency. In image processing and computer graphics, aliasing occurs when an image is sampled, resulting in patterns not present in the original image. A moiré lens array is a special case of an Alvarez lens array.

[0080] "Single component"

[0081] A single-unit component refers to a component made from a single part. A typical example of such a component is a single-pixel array, where the array is made from a single part, and the array's μ-LEDs are fabricated together on a carrier.

[0082] "Optical mode"

[0083] A mode is a description of a wave's specific time-static properties. The wave is described as a sum of different modes. These modes differ in their spatial distribution of intensity. The shape of a mode is determined by the boundary conditions of wave propagation. Analysis based on vibration modes can be applied to both standing waves and continuous waves. For electromagnetic waves such as light, lasers, and radio waves, the following types of modes are distinguished: TEM (transverse electromagnetic) mode, TE (transverse electric) or H (magnetic) mode, TM (transverse magnetic) or E (electric) mode. TEM (transverse electromagnetic) mode: Both the electric and magnetic fields are always perpendicular to the direction of propagation. This mode can only propagate when there are two isolated conductors (equipotential surfaces) in a coaxial cable or when there are no electrical conductors in a gas laser or optical waveguide. TE or H mode: Only the electric field component is perpendicular to the direction of propagation, while the magnetic field component points in the direction of propagation. TM or E mode: Only the magnetic field component is perpendicular to the direction of propagation, while the electric field component points in the direction of propagation.

[0084] "Optoelectronic components"

[0085] An optoelectronic component is a semiconductor substrate that generates light through recombination of charge carriers during operation, and then emits light. The emitted light can range from infrared to ultraviolet, with the wavelength depending on various parameters, the material system used, and the doping. Optoelectronic components are also known as light-emitting diodes (LEDs).

[0086] For the purposes of this disclosure, the terms optoelectronic component and light-emitting component are used synonymously. Therefore, in terms of its geometry, a μ-LED (see related description) is a specific type of optoelectronic component. In displays, optoelectronic components are typically monolithic or single components placed on a matrix.

[0087] "Passive matrix backplane" or "passive matrix carrier substrate"

[0088] A passive matrix display is a matrix display in which individual pixels are passively controlled (without additional electronic components for each pixel). The light-emitting diodes (LEDs) of the display can be controlled by the circuitry of an integrated circuit (IC). In contrast, a screen with active pixels controlled by transistors is called an active matrix display. A passive matrix carrier substrate is part of and supports the passive matrix display.

[0089] "Photonic crystal" or "photonic structure"

[0090] A photonic structure can be a photonic crystal, a quasi-periodic, or a deterministic aperiodic photonic structure. A photonic structure generates a band structure for photons through periodic variations in the optical refractive index. This band structure can have a band gap within a specific frequency range. This means that photons cannot propagate through the photonic structure in all spatial directions. In particular, propagation parallel to the surface is generally blocked, but propagation perpendicular to the surface is possible. In this way, the photonic structure or photonic crystal determines propagation in a specific direction. It blocks or reduces the radiation along one direction and thus produces a radiation or a beam of radiation, directed as needed to a spatial region or emission region provided for this purpose.

[0091] Photonic crystals are photonic structures that appear or are generated in transparent solids. Photonic crystals are not necessarily crystals; their name comes from the diffraction and reflection effects of X-rays in crystals, due to their lattice constant. The structural size is equal to or greater than one-quarter of the photon's wavelength, meaning they range from 1 μm to several μm. They are generated using classical photolithography or through self-organizing processes.

[0092] Alternatively, similar or identical properties of photonic crystals can also be produced with aperiodic but still ordered structures. Such structures are in particular quasi-periodic or well-defined aperiodic structures. For example, this could be a helical arrangement of photons.

[0093] In particular, the so-called two-dimensional photonic crystal is mentioned here by way of example, which has a periodic variation of optical refractive index in two spatial directions that are perpendicular to each other, especially in two spatial directions that are parallel to the light emitting surface and perpendicular to each other.

[0094] However, one-dimensional photonic structures, particularly one-dimensional photonic crystals, also exist. One-dimensional photonic crystals exhibit a periodic change in refractive index along a single direction. This direction can extend parallel to the light exit surface. The one-dimensional structure allows beam shaping to occur in a first spatial direction. In a photonic structure, the photonic effect can be achieved in just a few cycles. The photonic structure can be designed, for example, to ensure that electromagnetic radiation is at least approximately collimated relative to the first spatial direction. Therefore, a collimated beam can be generated at least relative to the first spatial direction.

[0095] "Pixel"

[0096] The individual color values ​​of a digital photodiode pattern, and the surface elements required to record or display these color values ​​in an image sensor or screen with photodiode control, are called pixels, image points, image cells, or image dots. Therefore, a pixel is a positionable element in a display device and has at least one light-emitting device. Pixels have a definite size, and adjacent pixels are separated by a defined spacing or pixel space. In displays, especially μ displays, three (or several with added redundancy) sub-pixels of different colors are typically combined into one pixel.

[0097] "planar array"

[0098] A planar array is a substantially flat surface. It is typically smooth and has no protruding structures. Generally, surface roughness is undesirable and does not provide the desired functionality. A planar array is, for example, a monolithic planar array with multiple optoelectronic components.

[0099] Pulse width modulation

[0100] Pulse Width Modulation (PWM) is a type of modulation used to control components, particularly μ-LEDs. A PWM signal controls a switch configured to turn on and off the current flowing through the corresponding μ-LED, thus causing the μ-LED to light up or not. When using PWM, the output provides a square wave signal with a fixed frequency f. During each cycle T (= 1 / f), the relative amount of on-time compared to the off-time determines the brightness of the light emitted by the μ-LED. The longer the on-time, the brighter the light.

[0101] "Quantum trap"

[0102] A quantum well is understood as a potential line in a strip structure within one or more semiconductor materials, which restricts the degree of freedom of a particle to move in one spatial dimension (typically the z-direction). Thus, a charge carrier can only occupy a planar region (the xy-plane). The width of the quantum well determines the quantum mechanical states that the particle can adopt, resulting in the formation of energy levels (sub-bands), meaning the particle can only have discrete (potential) values.

[0103] "complex"

[0104] There is generally a distinction between radiative and nonradiative recombination. The latter produces a photon that can leave the component. Nonradiative recombination results in the generation of acoustic quanta, which heat the component. The ratio of radiative to nonradiative recombination is an important parameter that depends on the component size, among other factors. Typically, the smaller the component, the smaller the ratio, thus increasing nonradiative recombination relative to radiative recombination.

[0105] Refresh time

[0106] The refresh time is the time after which units such as displays must be rewritten to prevent information loss or premature refresh by external factors.

[0107] "Rohchip" or "light-emitting element"

[0108] A light emitter, or virgin chip, is a semiconductor structure fabricated on a wafer and then separated from it. This semiconductor structure is adapted to generate light after electrical contact during operation. Therefore, in this context, a virgin chip is a semiconductor structure containing active layers for generating light. Virgin chips are typically separated after contact, but can also be further processed in array form.

[0109] "Slot antenna"

[0110] A slot antenna is a special type of antenna in which, instead of surrounding the metallic structure with air (as a non-conductor) in space, an interruption is provided in the metallic structure (e.g., a metal plate, waveguide, etc.). This interruption causes the reflection of electromagnetic waves, the wavelength of which depends on the geometry of the interruption. Typically, the interruption follows the dipole principle, but theoretically it can have any other geometry. Therefore, a slot antenna comprises a metallic structure with a cavity resonator whose length is on the order of the visible light wavelength. The metallic structure can be arranged in or surrounded by an insulating material. The metallic structure is typically grounded to establish a certain potential.

[0111] Field of view

[0112] The field of view (FOV) refers to the area within the field of view of an optical device, solar sensor, camera's image surface (film or recording sensor), or perspective display where events or changes can be perceived and recorded. The field of view is specifically the area that a person can see without moving their eyes. Regarding augmented reality and prominent objects placed in front of the eyes, the field of view includes the area specified as multiple angles of view during stable eye fixation.

[0113] "Subpixel"

[0114] A subpixel describes the internal structure of a pixel. Generally, the term "subpixel" is associated with a higher resolution than that expected from a single pixel. A pixel can also contain several smaller subpixels, each emitting a different color. The overall color impression of a pixel is produced by the mixing of the individual subpixels. Therefore, a subpixel is the smallest locatable unit in a display device. Similarly, a subpixel has a specific size, smaller than the size of the pixel to which it belongs.

[0115] Vertical LED

[0116] Compared to horizontal LEDs, vertical LEDs have electrical connections on both the front and back sides. One of the two sides also forms a light-emitting surface. Therefore, a vertical LED has contacts formed on two opposing main surface sides. Consequently, a conductive yet transparent material must be deposited to ensure electrical contact while allowing light to pass through.

[0117] Virtual Reality

[0118] Virtual reality (VR) refers to the representation and simultaneous perception of reality and its physical properties in a real-time, computer-generated, interactive virtual environment. Virtual reality can replace the operator's real environment with a completely simulated environment.

[0119] The following sections will introduce various aspects of the μ-LED semiconductor structure. This includes the structural and material systems used for light emission. However, these aspects also involve key processing points.

[0120] In the field of augmented reality, and in automotive displays or other display devices with μ-LEDs, a fundamental aspect is that adjacent μ-LEDs in the device are also spaced apart as μ displays or μ arrays, making it impossible for the human eye to distinguish or identify individual μ-LEDs in such a device. Specifically, individual rows or columns of μ-LEDs arranged row by row or column by column cannot be distinguished or identified by the human eye. Therefore, the distance between μ-LEDs, or the pixel density and pixel pitch of the μ-LED array, should also be adjusted accordingly based on the distance between the observer and the μ-LED array, so that the observer's eye cannot distinguish individual μ-LEDs in the μ-LED array within the appropriate application.

[0121] Compared to arrays with organic LEDs (OLEDs) and liquid crystal displays (LCDs), μ-LED arrays have lower energy consumption and up to 10 6 Cd / m 2 The advantages of high brightness. Furthermore, μ-LED arrays can achieve extremely high pixel densities of up to 5000 pixels per inch (PPI) and nanosecond-level refresh rates when applied in displays. In addition, compared to OLED and LCD, μ-LED arrays have a very long lifespan and excellent stability in resisting environmental influences. Moreover, using μ-LED arrays allows for the adaptation of contrast range and / or resolution values ​​to desired values, such as application-specific adaptation.

[0122] Furthermore, arrays composed of μ-LEDs allow the light-emitting areas formed by the μ-LEDs to be adapted to fit desired shapes. This means that the application is not limited to ordinary displays, and μ-LED arrays can also be used in the automotive field, for example, using curved surfaces as displays or lighting devices. This area can be used to display information as well as a simpler light-emitting area for illumination or lighting.

[0123] One aspect involves the generation of different colors in a monolithic display. In a monolithic μ-LED array, each individual pixel can each contain, for example, a μ-LED that emits blue light, and each μ-LED can also have a converter material to partially or completely convert the blue light into secondary light, which, together with the blue primary light, produces mixed light, such as white light. Monolithic μ-LED arrays enable high brightness in the emitting area and are therefore advantageously used in automotive lamps, such as as a light source for automotive headlights.

[0124] Conversely, non-monolithic microdisplays or μ-LED arrays allow for the arrangement of other components, such as electronic components for operating the μ-LEDs, or sensors or detectors, using the gaps between adjacent pixels or μ-LEDs. Non-monolithic μ-LED arrays can be advantageously used, for example, in displays and displays with integrated sensors, particularly touchscreens, as well as for operating elements.

[0125] To reduce light loss, light emitted from the sidewalls is deflected by a reflector layer. In another approach, a reflective interface is proposed, which is directly disposed on the side of the optoelectronic component. Therefore, this method can be implemented in both monolithic structures and individual optoelectronic components. This method can also be provided, for example, in the case of μ-LED nanopillars or semiconductor stacks, as proposed in antenna structures.

[0126] In one aspect, the optoelectronic device includes at least one optoelectronic light source based on a semiconductor material, particularly in the form of a μ-LED, having an active region for generating light, wherein a light-emitting surface for generating light is formed on an upper side of the light source, wherein the light source has at least one additional interface near the upper side that limits the light source laterally and / or downwardly, and wherein a dielectric reflector is arranged on the interface, which is designed to reflect the generated light.

[0127] In contrast to or in addition to other measures that complement a reflector, a dielectric reflector is applied directly to the interface. Without a dielectric reflector, light generated in the light source may escape to the sides and / or downwards, and specifically into the material of the carrier surrounding the light source. Conversely, a dielectric reflector at least partially reflects the light impacting the interface back into the light source. Therefore, using a dielectric reflector can at least partially prevent light from escaping from the light source to the sides and / or downwards. Ideally, for example, after further reflection, the reflected light escapes through the light-emitting surface. Thus, light output can be improved using a dielectric reflector. Simultaneously, this component is very small.

[0128] The interface may have a side surrounding the light source and a bottom side of the light source in a circumferential direction, wherein the bottom side is opposite to the top side.

[0129] The dielectric reflector can be arranged on the side or only on the bottom surface. Alternatively, the dielectric reflector can be arranged on both the side and the bottom surface. Therefore, except for the top side, the dielectric reflector can be arranged on the entire interface defining the light source. Thus, except for the top side, the dielectric reflector can surround the entire light source, thereby achieving a relatively large increase in light output.

[0130] A dielectric reflector can have multiple stacked material layers, particularly a periodic or aperiodic sequence, with at least two directly consecutive material layers having different refractive indices. Specifically, a dielectric reflector can consist of a periodic sequence of two alternating dielectric material layers with different refractive indices. The thickness of the material layers can be adapted to the wavelength of light emitted by the light source in order to obtain the highest possible reflectivity.

[0131] Compared to periodic sequences of layers, aperiodic sequences of material layers can produce a mirroring effect comparable to thinner layers, at least in certain configurations. Dielectric reflectors, in particular, can be constructed as Bragg mirrors. Bragg mirrors are known in themselves. They are also called distributed Bragg reflectors, abbreviated as DBR.

[0132] A Bragg reflector can be formed by the periodic arrangement of two alternating thin layers of material with different refractive indices. These layers are typically composed of a dielectric based on a semiconductor material. At the interface between the two material layers, part of the incident light is reflected according to the so-called Fresnel equation. If the wavelength is approximately four times the wavelength of the light in the corresponding material layer, constructive interference will occur between the reflected radiation.

[0133] The range of wavelengths reflected by a Bragg mirror, especially in the case of perpendicularly incident light, is very high, and at least theoretically reaches 100% with a great many alternating layers, known as the stopband. Light with wavelengths within the stopband of a Bragg mirror is at least largely reflected, and ideally, cannot propagate through the Bragg mirror.

[0134] Therefore, the reflector designed as a Bragg reflector is preferably designed such that the wavelength of the light emitted from the light source is within the stopband, particularly at its center. The thickness of the material layer of the Bragg reflector is then matched to the wavelength of the emitted light. The optical thickness of the layer is preferably one-quarter of the wavelength of the emitted light. The optical thickness corresponds to the product of the layer thickness and the optical refractive index.

[0135] Some aspects of this design also relate to an optoelectronic device, such as a display device, a monolithic array, or a headlight, such as a matrix headlight, wherein the optoelectronic device has a plurality of proposed optoelectronic devices, wherein the light sources of the optoelectronic device are arranged in an array. Each light source can form a pixel of the display or monolithic array. It may be proposed that each light source emits light of one of a plurality of predetermined colors, such as red, green, and blue. Each light source can form a sub-pixel of a pixel, which is formed by a plurality of light sources, wherein each light source emits light of one color.

[0136] The light source of an optoelectronic device can be embedded in a carrier, specifically in such a way that only the light-emitting surface of the light source is exposed as a free external upper side, while the various interfaces of the light source are surrounded by the carrier material. The dielectric reflector of the optoelectronic device can be located between the interface between the light source and the carrier material. The carrier can, for example, have one or more layers of semiconductor material. These layers can include wires, for example, in the form of one or more printed wires. Electronic circuitry can also be included to power or control the light source. For example, the light source can be powered by printed wires.

[0137] Other aspects of the proposed design also relate to a method for manufacturing optoelectronic devices, particularly display devices or headlights, wherein a optoelectronic light source based on semiconductor materials is provided, wherein the light source has an active region for generating light and a light-emitting surface on an upper side for generating light, and wherein a dielectric reflector is arranged on at least one interface of the light source, the dielectric reflector being designed to reflect the generated light, and wherein the interface confines the light source to the side and / or downwards.

[0138] Except for the top side, the interface can form the rest of the outer side of the light source. The reflector can completely or at least partially cover the interface.

[0139] A method for manufacturing an optoelectronic device, such as a display device or a headlight device, is also proposed. In some aspects, in this method, light sources of a plurality of optoelectronic devices according to the invention are arranged in an array and embedded in a carrier such that only the light-emitting surface of the light source shows a free outer upper side, while the material of the carrier surrounds the interface of the light source. Dielectric reflectors may be arranged between the material of the carrier and the corresponding interface of the light source. This step can be performed before embedding the light source in the carrier.

[0140] The proposed design also relates to a method for manufacturing optoelectronic devices, such as monolithic arrays or headlights, particularly having multiple proposed optoelectronic devices or μ-LEDs. In this method, multiple semiconductor-based optoelectronic light sources are formed on a carrier in an array-like manner, such that each light source has an active region for generating light and a free external upper side as a light emission surface, and wherein for each light source, a dielectric reflector is arranged at at least one interface, which, relative to the material of the carrier, defines the light source laterally and / or downwardly and is designed to reflect the generated light.

[0141] The arrangement of dielectric reflectors can include applying material for the dielectric reflector using atomic layer deposition (ALD). ALD is also known as atomic layer deposition. The material used to form the dielectric reflector can be deposited in a very thin layer. Layer thicknesses corresponding to atomic monolayers can be achieved. Thus, even on non-planar surfaces (e.g., curved surfaces), layers with precisely defined thicknesses can be deposited. In particular, reflectors designed as Bragg mirrors can be fabricated in a simple manner using ALD.

[0142] For example, Nb₂O₅, TiO₂, ZrO₂, HfO₂, Al₂O₃, Ta₂O₅, or ZnO can be used as materials for the dielectric layer of a reflector with a high refractive index. For example, SiO₂, SiN, SiON, or MgF₂ can be used for the dielectric layer with a low refractive index.

[0143] The arrangement of the dielectric reflector may include: arranging at least one layer of material for the dielectric reflector by a first method, and arranging material for other layers by a second method. Specifically, the layer at the interface directly adjacent to the light source can be arranged by the first method. The first method may be, for example, a vapor deposition method, such as particularly CVD (for chemical vapor deposition) or PE-CVD (for plasma-enhanced chemical vapor deposition). In this way, unevenness at the interface, such as rough surfaces caused by etching processes, can be covered by a more suitable deposition. More dielectric mirrors can then be produced on a smooth surface.

[0144] The second method can be atomic layer deposition. This allows for the formation of layers for dielectric reflectors with a defined thickness.

[0145] Another aspect also relates to a method for manufacturing an optoelectronic device, or particularly an optoelectronic device having multiple optoelectronic devices as proposed herein, wherein, in this method, optoelectronic light sources based on semiconductor materials are arranged in an array on a carrier such that each light source has an active region for generating light and has a free outer upper side as the light emitting surface of the light, the light sources are arranged such that there is at least a small gap between adjacent light sources on the upper side, having an intermediate space therebetween, wherein, for each light source, a dielectric reflector is arranged on at least one interface, the reflector defining the light source laterally and / or downwardly relative to the material of the carrier and is designed to reflect the generated light, and wherein the dielectric reflector of the light source is thus formed, for example by atomic layer deposition, by introducing material for the dielectric reflector from the upper side into the corresponding gap between adjacent light sources and forming the dielectric reflector in the corresponding intermediate space behind the gap.

[0146] At least the light-emitting surface of the light source can be specifically covered with a photomask, while a dielectric reflector is formed in the intermediate space. After the reflector is installed, the photomask can be removed. The proposed headlight can be a matrix headlight. The headlight assembly can therefore be a matrix headlight assembly. Attached Figure Description

[0147] The following sections use various design schemes and examples to illustrate some of the aspects mentioned above and summarized in more detail.

[0148] Figure 1 The diagram illustrates some requirements for a so-called μ display or microdisplay device in terms of various dimensions of field of view and pixel spacing in a μ display; Figure 2 A diagram showing the spatial distribution of rod and cone cells in the human eye; Figure 3 A diagram showing the perceptual abilities of the human eye with assigned projection areas; Figure 4 A graph showing the sensitivity of rod and cone cells at different wavelengths is presented; Figure 5 The diagram illustrates some requirements for microdisplays of various sizes in terms of the field of view and collimation of pixels in a μ display; Figure 6 An exemplary design of a pixel array is shown to illustrate... Figure 1 and Figure 5 The parameters represented in the text; Figure 7 A graph showing the required number of pixels depends on the number of fields of view for a given resolution; Figure 8A cross-sectional view of an optoelectronic device, such as a display device, having multiple optoelectronic devices according to some aspects of the invention is shown; Figure 9 A cross-sectional view of another optoelectronic device with multiple optoelectronic devices designed as μ-LEDs, based on the proposed design, is shown. Figure 10 Another proposed cross-sectional view of a monolithic array with multiple optoelectronic devices is shown; Figure 11 A cross-sectional view of another monolithic array with multiple optoelectronic devices designed as μ-LEDs is shown; and Figure 12 An example based on the previous structure shows a monolithic array with a light-shaping structure; Figure 13 A cross-sectional view of the dielectric reflector is shown. Detailed Implementation

[0149] Augmented reality is largely created by a dedicated display that overlays images onto reality. This display can be placed directly in the user's line of sight, i.e., directly in front of them. Alternatively, beam deflection elements can be used to direct light from the display toward the user's eyes.

[0150] In both cases, a display can be implemented, and the user can wear glasses or other visual augmentation devices as part of the device. Google's™ Glasses is an example of such a visual augmentation device, allowing users to overlay certain information about objects in the real world. With Google™ Glasses, the information is displayed on a small screen in front of the glasses. In this respect, the appearance of this add-on device is a key feature of the glasses, combining technological functionality with the design aspects of wearing glasses. Simultaneously, users need glasses that don't have such bulky or easily damaged devices to provide augmented reality functionality. Therefore, one concept is that the glasses themselves become a display or at least one screen, with information projected onto or into a projector.

[0151] In this type of situation, the user's field of view is limited to the size of the glasses. Therefore, the area on which augmented reality can be projected is approximately the size of the glasses lenses. The same but different information can be projected onto or onto both lenses of a pair of glasses.

[0152] In other words, the image experienced by a user while wearing augmented reality glasses should have a resolution that creates a seamless impression, so that the user doesn't perceive augmented reality as a pixelated object or a low-resolution element. Straight bevels, arrows, or similar elements appear as staircase-like outlines at low resolutions, which is distracting for the user.

[0153] To achieve an ideal visual impression, two display parameters are considered important, as they influence the visual impression for a given or known human eye. One is the pixel size itself, the geometry and dimensions of a single pixel, or the area of ​​three subpixels representing that pixel. The second parameter is the pixel pitch, the distance between two adjacent pixels or subpixels, which varies depending on the context. Sometimes, pixel pitch is also referred to as the space between pixels. Larger pixel gaps can be detected by the user and perceived as gaps between pixels, potentially leading to what is known as the "flying screen effect." Therefore, the gap should not exceed a certain limit.

[0154] The maximum angular resolution of the human eye is typically between 0.02 and 0.03 arcminutes, roughly equivalent to 1.2 to 1.8 arcminutes per line. This results in a pixel pitch of 0.6-0.9 arcminutes. Some current mobile phone displays have approximately 400 pixels per inch, resulting in a viewing angle of approximately 2.9° at a distance of 25 cm from the user's eyes, or approximately 70 pixels per degree. Therefore, the distance between two pixels in such a display is within the range of maximum angular resolution. Furthermore, the pixel size itself is approximately 56 μm.

[0155] Figure 1 The pixel spacing is shown, that is, the distance between two adjacent pixels that depends on the field of view. In this respect, the field of view is the extension of the observable world seen at a given moment. This is because human vision is defined as the angle of view in degrees during a stable fixation of the eye.

[0156] In particular, the forward horizontal curvature of the binocular visual field is slightly higher than 210°, while the vertical curvature of the human visual field is approximately 135°. However, the range of visual ability is not uniform across the entire visual field and may vary from person to person.

[0157] Human binocular vision covers approximately 114° horizontally (peripheral vision) and approximately 90° vertically. The remaining degrees on both sides do not constitute binocular vision, but can be considered part of the field of view.

[0158] Furthermore, color vision and the ability to perceive shape and motion further limit the horizontal and vertical fields of vision. The rods and cones responsible for color vision are unevenly distributed.

[0159] This viewpoint Figures 2 to 4 This was explained in more detail. In the central visual domain, that is, directly in front of the eyes, as required by augmented reality applications, and partly in the automotive field, the eye's sensitivity is very high in terms of spatial resolution and color perception.

[0160] Figure 2 The spatial density of cones and rods per square millimeter is shown, which is related to the angle of the central concave region. Figure 3The wavelength-dependent color sensitivity of cones and rods is described. In the central region of the fovea, increased cone density (L, S, and M) leads to better color perception. Sensitivity begins to decrease at a distance of approximately 25° around the fovea, as the density of visual cells decreases. Near the edges, color perception decreases further, but contrast vision through rods remains over a wider angular range. Overall, this creates a radially symmetrical visual pattern for the eye, rather than a Cartesian one. Therefore, high resolution of all primary colors is necessary, especially at the center. At the edges, working with an emitter adapted to the spectral sensitivity of rods may suffice (maximum sensitivity 498 nm, see...). Figure 4 And the sensitivity of the eyes).

[0161] Figure 3 The graph of angular resolution A relative to the angular deviation α from the optical axis of the eye illustrates the different perceptual abilities of the human eye. It can be seen that the highest angular resolution A exists within the interval of + / - 2.5° angular deviation α, where the fovea 7 is arranged on the retina 19 with a diameter of 1.5 mm. Furthermore, the location of the blind spot 22 on the retina 19 is plotted, which appears in the region of the optic disc 23, with an angular deviation α of approximately 15°.

[0162] The eye can compensate for this non-constant density, and it can also compensate for so-called blind spots through minute eye movements. This change in the direction or focus of the gaze can be counteracted through appropriate optical systems and eye tracking.

[0163] In addition, even when wearing glasses, the field of vision is further limited; for example, the field of vision of each lens can be within approximately 80°.

[0164] Figure 1 The pixel pitch on the Y-axis, measured in μm, defines the distance between two adjacent pixels. Different curves, C1 to C7, define the diagonal dimensions of the corresponding displays, ranging from 5mm to approximately 35mm. For example, curve C1 corresponds to a display with a diagonal dimension of 5mm, meaning a side length of approximately 2.25mm. For a field of view of approximately 80°, the pixel pitch of a display with a 5mm diagonal dimension is within the range of 1μm. For larger displays, such as those using curve C7 and a 35mm diagonal dimension, the same field of view can be achieved with a pixel pitch of approximately 5μm.

[0165] However, Figure 1 The curves in the diagram illustrate that a larger field of view is preferred for augmented reality applications, while very high pixel density and small pixel pitch are required to avoid the well-known screen-flying effect. We can now calculate the pixel size for a given number of pixels, a given field of view, and a given diagonal size for a μ display.

[0166] Equation 1 shows the relationship between pixel size D, pixel pitch pp, number of pixels N, and display edge length d. The distance r between two adjacent pixels, calculated from their respective centers, is given by the following equation.

[0167] r = d / 2 + pp + d / 2.

[0168] D = d / N-pp (1)

[0169] N = d / (D + pp)

[0170] Assuming the distance between the monitor (e.g., glasses) and the eye is 2.54 cm (1 inch), then for the roughly estimated 1 arcminute angular resolution above, the distance r between two adjacent pixels is...

[0171] r = tan(1 / 60°) × 30mm

[0172] r = 8.7μm

[0173] Therefore, pixel size is less than 10 μm, especially when a certain space is required between two different pixels. Using the distance r between two pixels and a display with a size of 15 mm × 10 mm, 1720 × 1150 pixels can be arranged on the surface.

[0174] Figure 6 An arrangement with a carrier 21 is shown, on which a plurality of pixels 20 and 20a to 20c are arranged. Pixels 20 arranged adjacent to each other have a pixel pitch pp, while pixels 20a to 20c are placed on the carrier 21 with a larger pixel pitch pp. The distance between two pixels is given by the sum of the pixel pitch and half the size of each adjacent pixel. Each pixel 20 is configured such that its illumination characteristics, or emission vector 22, are substantially perpendicular to the emission surface of the corresponding LED.

[0175] The angle between the vertical axis on the emitting surface of the LED and the beam vector is defined as the collimation angle. In the example of emission vector 22, the collimation angle of LED 20 is approximately zero. LED 20 emits collinear light and does not expand significantly.

[0176] Conversely, the collimation angle of the emission vector 23 of LED pixels 20a to 20c is very large, and is in the range of approximately 45°. As a result, a portion of the light emitted by LED 20a overlaps with the emission of the adjacent LED 20b.

[0177] The emission of LEDs 20a to 20c partially overlaps, resulting in the superposition of their respective light emissions. If the LEDs emit different colors of light, the result will be a mixture or combination of colors. A similar effect occurs between high-contrast areas, i.e., when LED 20a is dark while LED 20b emits some kind of light. Due to the overlap, the contrast is reduced, and the information at each individual location corresponding to the pixel position is also reduced.

[0178] For displays with a small distance from the user's eyes, such as those mentioned above, a large collimation angle can be quite annoying due to the aforementioned effects and other drawbacks. Users can perceive a large collimation angle and may experience a slight difference in the color of depicted objects, a blurriness, or reduced contrast.

[0179] in this regard, Figure 5 This illustrates the collimation angle in degrees relative to the field of view in degrees, which is independent of a specific display size. For smaller display sizes, such as those in curve C1 (approximately 5 mm diagonally), the collimation angle increases significantly depending on the field of view.

[0180] As monitor sizes increase, the requirements for collimation change dramatically. Therefore, even with large monitor geometries, as shown by curve C7, the collimation angle reaches approximately 10° within a 100° field of view. In other words, the collimation requirements increase for larger monitors and larger fields of view. In such monitors, the light emitted from the pixels must be highly collimated to avoid or reduce the aforementioned effects. Therefore, when providing users with monitors that offer large fields of view, even if the monitor's geometry is relatively large, robust collimation capabilities are necessary.

[0181] Based on the above charts and equations, it can be deduced that as the geometry and field of view of a display increase, the requirements regarding pixel pitch and collimation become increasingly challenging. As Equation 1 shows, the size of a display increases dramatically with the number of pixels. Conversely, a large field of view requires a large number of pixels to achieve sufficient resolution and avoid screen flickering or other interference effects.

[0182] Figure 7 The diagram illustrates the number of pixels required to achieve an angular resolution of 1.3 armes. For a field of view of approximately 80°, the number of pixels exceeds 5 million. It can be quickly estimated that the pixel size for QHD resolution is far less than 10μm, even with a display size of 15mm × 10mm. In total, an augmented reality display with resolutions in the HD range (i.e., 1080p) requires a total of 2,073,600 pixels. This would cover a field of view of approximately 50°. The number of pixels arranged in a 10 × 10mm display with a pixel spacing of 1μm would result in a pixel size of approximately 4μm.

[0183] The above considerations make it clear that the challenges in terms of resolution, collimation, and field of view suitable for augmented reality applications are considerable. Therefore, the technical implementation of such displays also places very high demands on them.

[0184] Traditionally used technologies were designed for manufacturing displays with LED edge lengths in the range of 100 μm or even longer. However, they cannot automatically scale to the 70 μm and below dimensions required here. Pixel sizes of a few μm and distances of a few μm or even smaller, closer to the order of magnitude of the generated light wavelength, require new processing technologies.

[0185] Furthermore, new challenges have emerged in light collimation and guidance. For example, optical lenses that can be easily structured into larger LEDs and calculated using classical optics cannot be directly scaled down to such small sizes without using Maxwell's equations. In addition, it is nearly impossible to manufacture small lenses without large errors or deviations. In some variants, quantum effects affect the behavior of pixels of these sizes and must be taken into account. Tolerance requirements in the production or transmission techniques of pixels on auxiliary carriers or matrix structures are becoming increasingly stringent. Pixels must also be contactable and individually controllable. Conventional circuitry has space requirements that, in some cases, exceed the pixel area, creating placement and space issues.

[0186] Therefore, new designs for controlling and accessing pixels of this size may be entirely different from traditional technologies. Finally, a key focus is on the power consumption of such displays and controls. Low power consumption is particularly desirable for mobile applications.

[0187] In summary, many designs suitable for larger pixel sizes require extensive modifications before successful scaling down. While a design suitable for producing 200 μm LEDs can be easily scaled up to 2000 μm LEDs, scaling down to 20 μm is much more difficult. Many documents and literature disclosing such designs do not account for the various effects and increased requirements of extremely small sizes, and therefore are not directly applicable to or limited to pixel sizes significantly larger than 70 μm.

[0188] The following sections present various aspects of the structure and fabrication of μ-LED semiconductors, including processing, optical coupling output and light guidance, display, and control. These are suitable for designing displays with pixel sizes of 70 μm and below. Some designs are specifically designed for the production, optical coupling output, and control of μ-LEDs with edge lengths less than 20 μm, particularly less than 10 μm. It goes without saying that the designs presented here regarding these aspects can and should be combined with each other. For example, this relates to the design of μ-LEDs with designs for producing coupled output light. Specifically, μ-LEDs implemented, for example, by methods to avoid edge defects or by current conduction or current contraction, can provide optical coupling output structures based on photonic crystal structures. Special control can also be implemented for displays with variable pixel sizes. Light guidance with piezoelectric mirrors can be implemented in μ-LED displays based on slot antennas or conventional monolithic pixel matrices.

[0189] In some of the design options and aspects described below, additional examples of various design options or combinations of their aspects are indicated. These are intended to clearly show that those skilled in the art can combine the aspects, design options, or parts thereof with each other. Some applications require specially modified designs, while others have lower technical requirements. Automotive applications and displays, for example, typically have larger pixel edge lengths due to the greater distance from the user. In particular, there are classic pixel applications or virtual reality applications, in addition to augmented reality applications. In the context of this disclosure, this is also clearly desirable for realizing μ-LED displays with pixel edge lengths below 70 μm.

[0190] In a monolithically arranged μ-LED array, such as in a display, crosstalk can be reduced through reflective interfaces between individual pixels or μ-LEDs. Simultaneously, light is emitted along the main radiation direction, thereby improving efficiency. The example described below is of a μ-display device 11. Figure 8 The optoelectronic components shown include a number of these proposed optoelectronic components 13. The optoelectronic components 13 are further processed μ-LEDs, each μ-LED forming a pixel or sub-pixel of an LED display. Although the μ display device 11 is mentioned below, this is merely an example, and optoelectronic devices are not limited to this example.

[0191] Each optoelectronic device 13 has a light source 15, which is a semiconductor component composed of multiple semiconductor layers. Due to its size and function, this semiconductor component is also referred to as a μ-LED. The semiconductor layers are formed, in particular, in a manner known per se as active regions (not shown) for generating light. The light sources 15 are arranged in an array on a carrier 17. Due to the array arrangement, the light sources 15 form multiple rows or columns of light sources on the carrier 17.

[0192] It can be proposed that each light source 15 and therefore each device 13 emits light of a specific wavelength, i.e., light of a specific color, in a variety of possible wavelengths or colors. A device 13 emitting light of a certain color can be considered a sub-pixel of a pixel. A pixel can have other sub-pixels, each formed by an adjacent light source or device and emitting light in other possible colors.

[0193] For example, to achieve RGB pixels (RGB for red, green, and blue), three light sources 15 can form a pixel, with one of the light sources 15 emitting red light, one of the light sources 15 emitting green light, and one of the light sources 15 emitting blue light. In this way, an RGB display device can be formed.

[0194] The material 25 of the carrier 17 surrounds each light source 15 except for its upper side 19. On the upper side 19 of each light source 15, which is not surrounded by the material 25, a light-emitting surface is provided for the generated light. Functionally, the light source 15 is demarcated from the carrier material 25 via interface 21. Figure 8 As shown, interface 21 defines the boundaries of light source 15 from the sides and below. Therefore, except for the upper side 19, interface 21 surrounds the entire outer surface of the corresponding light source 15, which corresponds to the surface of a partially ellipsoidal body. This is only an example, as other surface shapes are possible. For example, a parabolic orientation of the interface is also possible. However, in both cases, the light is emitted along the direction of the main emitting surface 19, i.e., upwards as shown.

[0195] The material 25 of the carrier 17 may have a filling material. The material 25 may also include electrical devices, such as printed wires in one or more layers, for individually supplying current to and controlling the light source 15. Therefore, the material 25 need not be a homogeneous material, but can be an arrangement composed of several materials. Additional electronic circuitry, such as supply or control circuitry, may be formed in the material 25.

[0196] In the case of each light source 15, a dielectric reflector 23 is arranged at the interface 21, which at least partially reflects the light generated in the active region of the respective light source 15. Therefore, the light generated in the light source 15 cannot escape, or only slightly escapes, through the interface 21 into the carrier material 21. Instead, at least most of the light is reflected back into the light source 15 at the interface 21 and lingers around the light source 15 until it is emitted upwards through the light-emitting surface. Thus, the light output can be increased by using the reflector 23.

[0197] according to Figure 9 The display device 11 and Figure 8The main difference between the variants is that the light source 15 has a different, approximately canister-shaped or trapezoidal cross-section. Therefore, the interface 21 has a side 27 extending circumferentially around the corresponding light source 15 and a lower side 28 opposite the upper side 19. The circumferential direction here extends around a normal N that extends perpendicularly to the upper surface 19.

[0198] According to Figure 9 In the case of the display device 11, the dielectric reflector 23 is arranged both on the side 27 and on the bottom 28. Therefore, except for the top 19, the dielectric reflector 23 completely surrounds each light source 15. In a modified embodiment, it may be proposed that the dielectric reflector 23 is arranged only on the side 27 or only on the bottom 28.

[0199] An exemplary variant of a display device 11 having a plurality of optoelectronic devices 13 arranged in an array is shown. Figure 8 and Figure 9 The difference lies in Figure 10 and Figure 11 The image shows a monolithic array 29. According to... Figure 10 The monolithic array 29 includes an optoelectronic device 13, which is connected to... Figure 8 It is constructed in the same way as optoelectronic devices. Furthermore, according to... Figure 11 The monolithic array 29 includes an optoelectronic device 13, which is connected to a source from... Figure 9 The optoelectronic devices are constructed in the same manner. Therefore, the same reference numerals are used for corresponding elements.

[0200] exist Figure 10 and Figure 11 In some variations, a continuous, at least partially transparent overlay layer 33 may be arranged above the light source 15 and the carrier 17. The overlay layer is also conductive, thus forming a common port for all the light sources 15.

[0201] Figure 12 yes Figure 11This is a supplement to the design scheme. Here, the photoforming structure is integrated in the upper side 19, and particularly in the case of semiconductor materials. The photoforming structure comprises a periodic arrangement of regions with different refractive indices. This periodic arrangement can be one or more of the structures disclosed in this application. In the illustrated design, the periodic structure is integrated in the semiconductor material in the surface region. For this purpose, the structure is etched into the semiconductor material and then filled with a second material with a different refractive index, thereby forming a photonic crystal. It is advantageous to form the photonic crystal in the semiconductor material itself because there is no additional refractive index transition between the semiconductor material and the photonic crystal in this way, which could reduce efficiency in some cases. The height of the photonic structure roughly corresponds to the wavelength, i.e., it is in the range of several hundred nm, depending on the wavelength of the light emitted in the material. The material in the filled region should be transparent to maintain the lowest possible light absorption. In this case, a converter material, such as quantum dots in an emulsion, can also be introduced into the etched region, so that the periodic structure has both photoforming and light conversion properties.

[0202] The examples of light-forming structures shown here, with their various aspects, can be applied to μ-LED devices, pixels, or other designs with arrays of such pixels.

[0203] Figure 13 A cross-sectional view of the dielectric reflector 23 is shown. The dielectric reflector 23 consists of a periodic sequence of two alternating layers 30 and 31 arranged between the interface 21 of the light source 15 and the material 25 of the carrier 17. Layers 30 and 31 are each formed of a dielectric, wherein the optical refractive index of the dielectric of layer 30 is different from that of the dielectric of layer 31. In the example shown, three layers 30 and three layers 31 are provided, but different numbers of layers can also be provided, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 layers respectively. For example, only one high-refractive-index layer can be provided between two low-refractive-index layers. In cases where the pixel size is very small, there may not be enough space between two low-refractive-index layers to accommodate more than one high-refractive-index layer.

[0204] Layers 30 and 31 can be arranged to form a Bragg mirror. When layers 30 and 31 have an optical thickness of one-quarter wavelength, maximum reflectivity of the wavelength of light emitted by the associated light source 15 is achieved. The optical thickness corresponds to the product of the refractive index and the layer thickness.

[0205] The fabrication of layers 30 and 31 can be achieved, for example, by atomic layer deposition. The nominal thickness of each layer 30 and 31 can be precisely achieved by layer-by-layer deposition. In particular, layers 30 and 31 can be made correspondingly thin, thereby satisfying the condition mentioned above, according to which layers 30 and 31 should have an optical thickness of one-quarter wavelength. In this way, a very efficient reflector can be produced. The atomic layer deposition method also enables the interface 21 to be uniformly reshaped, so that even narrow gaps can highlight a high aspect ratio. Furthermore, the remaining intermediate space to the carrier material 25 can be filled with a filler material.

[0206] In the modified design, the first bottommost layer 30a directly adjacent to interface 21 can be applied using different techniques such as CVD or PE-CVD. This allows for more conformal deposition to cover unevenness of interface 21, such as rough surfaces caused by etching processes. The remaining layers 30, 31 can then be applied onto the smooth layer 30a via atomic layer deposition.

[0207] exist Figures 8 to 11 Among the variants, such as Figure 13 As shown in the example, the dielectric reflector 23 causes light to be reflected at least partially backward into the interior of the light source 15. This is especially true for light incident perpendicularly on the reflector 23. Therefore, light generated in the light source 15 cannot escape, or only minimally escapes, through the interface 21 into the material 25 of the carrier 17 laterally and / or downward. The reflected light remains in the light source 15 and escapes upward in large quantities through the light-emitting surface. This can thus increase light output.

[0208] The term "light" should be understood broadly here, and specifically refers to electromagnetic radiation produced by the corresponding light source 15. In addition to visible light, the term "light" may also include infrared and / or ultraviolet light.

[0209] In the following sections, various devices and apparatuses, as well as methods for their manufacture, processing, and operation, are again listed as examples. The following items illustrate aspects and implementations of the proposed principles and designs that can be combined in various ways. Such combinations are not limited to those given below: 297. A photoelectric device, particularly a display device or headlight, comprising: - At least one light source having a semiconductor layer sequence having an active region for generating light. A light-emitting surface for generating light is formed on the upper side of the light source. In addition to the upper side, the light source also has at least one other interface that restricts the light source to the side and / or downward. Its features are, A dielectric reflector is placed at the interface, and the reflector is designed to reflect the generated light.

[0210] 298. The optoelectronic device according to item 297, characterized in that the interface has a side surface and a bottom surface extending circumferentially around the light source, the bottom surface being opposite to the upper surface.

[0211] 299. The optoelectronic device according to item 298, characterized in that the dielectric reflector is arranged on the side or on the bottom surface, or

[0212] The dielectric reflector is arranged on both the side and the bottom surface.

[0213] 300. The optoelectronic device according to any one of the preceding items, characterized in that, except for the upper side, the dielectric reflector is disposed on the entire interface defining the light source.

[0214] 301. The optoelectronic device according to any one of the preceding items, characterized in that the dielectric reflector is formed on two opposite sides of the light source.

[0215] 302. The optoelectronic device according to any one of the preceding items, characterized in that the dielectric reflector has two alternating sequences of material layers with different refractive indices, particularly a periodic or aperiodic sequence.

[0216] 303. The optoelectronic device according to any one of the preceding items, wherein the dielectric reflector is designed to have at least one contact conductive layer electrically connected to a contact of a light source, such that the current direction within the semiconductor layer sequence is opposite to the current direction passing through the conductive layer.

[0217] 304. The optoelectronic device according to item 301, wherein the conductive layer extends substantially parallel to the side of the semiconductor layer sequence.

[0218] 305. The optoelectronic device according to any one of items 302 to 304 above, wherein the contact conductive layer of the dielectric reflector is formed on two opposite sides, and the dielectric reflector is formed on two other sides without such a contact conductive layer.

[0219] 306. The optoelectronic device according to any one of the preceding items, characterized in that the thickness of the material layer is matched to the wavelength of the emitted light, such that the dielectric reflector reflects the light of that wavelength.

[0220] 307. The optoelectronic device according to any one of the preceding items, characterized in that the dielectric reflector is designed as a Bragg mirror.

[0221] 308. The optoelectronic device according to any one of the preceding items further includes: - A converter material on a light-emitting surface, wherein the converter material has an inorganic dye or quantum dots.

[0222] 309. The optoelectronic device according to any one of the preceding items further includes: - Light-forming structures, especially photonic structures or microlenses, on the light-emitting surface.

[0223] 310. The optoelectronic device according to the foregoing item, wherein the photoforming structure has at least one of the following characteristics: - The light-shaped structure includes periodic regions with different refractive indices; - The photoforming structure includes a first region and a second region with different refractive indices; wherein, the converter material forms the first region; - The photoforming structure is formed at least partially in the semiconductor layer sequence.

[0224] 311. A microdisplay device or monolithic array or headlight device having a plurality of optoelectronic devices according to any one of the preceding items, wherein the light sources of these optoelectronic devices are arranged in an array.

[0225] 312. The micro display device according to any one of the preceding items, characterized in that, The light source of the optoelectronic device is embedded in the carrier. In particular, this method makes only the light-emitting surface of the light source represent the free outer surface, while the other interfaces of the light source are surrounded by the material of the carrier.

[0226] 313. A method for manufacturing optoelectronic components, particularly display devices or headlights, wherein: A photoelectric light source based on semiconductor materials is provided, the light source having an active region for generating light and a light-emitting surface for emitting light generated on the upper side, and A dielectric reflector is disposed on the interface of the light source, preferably excluding the top side, and the reflector is designed to reflect the generated light. The interface confines the light source to the sides and / or downwards.

[0227] 314. A method for manufacturing an optoelectronic device, particularly a display device or a headlight device, wherein, in this method, a light source consisting of a plurality of optoelectronic devices according to any one of the preceding items is arranged in an array and placed in a carrier such that only the upper side of the light emitting surface of the light source represents a free outer surface, otherwise the other material of the carrier surrounds the interface of the light source.

[0228] 315. A method for manufacturing a μ display, a monolithic array, or a headlight device, particularly a method having a plurality of optoelectronic devices according to any one of the preceding items, wherein in the method

[0229] The optoelectronic light sources based on semiconductor materials are arrayed on the carrier, such that each light source has an active region for generating light and a free outer upper side that serves as a light emitting surface. In this configuration, a dielectric reflector is arranged on at least one interface for each light source, which, relative to the material of the carrier, defines the light source to the side and / or downwards, and is designed to reflect the light generated in the light source.

[0230] 316. The method according to any one of the preceding items, characterized in that arranging the dielectric reflector includes applying material to the dielectric reflector by means of atomic layer deposition.

[0231] 317. The method according to any one of the preceding items, characterized in that arranging the dielectric reflector comprises: arranging at least one layer of material for the dielectric reflector by a first method, and arranging material for other layers by a second method, wherein, preferably, the first method is a vapor deposition method, and wherein the second method is preferably an atomic layer deposition method.

[0232] 318. A method for manufacturing a μ display, particularly comprising a plurality of optoelectronic devices according to any one of the preceding items, wherein, in the method

[0233] The optoelectronic light sources based on semiconductor materials are arranged in an array on the carrier, such that each light source has an active region for generating light and a free outer upper side that serves as a light emission surface. The light sources are arranged such that there is at least a tiny gap between adjacent light sources on the upper side, which has a middle space at the rear. Specifically, a dielectric reflector is arranged at at least one interface for each light source, which, relative to the material of the carrier, defines the light source to the side and / or downwards. The dielectric reflector is designed to reflect light generated in the light source. Among them, the dielectric reflector forming the light source is formed by introducing the material for the dielectric reflector from the top into the corresponding gap between adjacent light sources, especially by atomic layer deposition, and forming the dielectric reflector in the intermediate space behind the gap.

[0234] 319. The method according to item 318, characterized in that at least the light emitting surface of the light source is covered, in particular, by a photomask, while a dielectric reflector is formed in the intermediate space.

Claims

1. A photoelectric device, particularly a display device or headlight, comprising: - At least one light source having a semiconductor layer sequence having an active region for generating light. in, A light-emitting surface for generating light is formed on the upper side of the light source. In addition to the upper side, the light source also has at least one other interface that restricts the light source to the side and / or downward. Its features are, A dielectric reflector is placed at the interface, and the reflector is designed to reflect the generated light.

2. The optoelectronic device according to claim 1, characterized in that, The interface has a side surface and a bottom surface that extend circumferentially around the light source, with the bottom surface opposite the top surface.

3. The optoelectronic device according to claim 2, characterized in that, The dielectric reflector is arranged on the side or on the bottom surface, or The dielectric reflector is arranged on both the side and the bottom surface.

4. The optoelectronic device according to claim 1, characterized in that, Except for the top side, the dielectric reflector is positioned on the entire interface that defines the light source.

5. The optoelectronic device according to claim 1, characterized in that, Dielectric reflectors are formed on two opposite sides of the light source.

6. The optoelectronic device according to claim 1, characterized in that, Dielectric reflectors have a periodic or aperiodic sequence of two alternating material layers with different refractive indices.

7. The optoelectronic device according to claim 1, wherein, The dielectric reflector is designed to have at least one contact conductive layer that is electrically connected to a contact of the light source, such that the direction of the current within the semiconductor layer sequence is opposite to the direction of the current passing through the conductive layer.

8. The optoelectronic device according to claim 7, wherein, The conductive layer extends substantially parallel to the sides of the semiconductor layer sequence.

9. The optoelectronic device according to claim 6, wherein, The dielectric reflector has a contact conductive layer formed on two opposite sides, and the dielectric reflector has another two sides without such a contact conductive layer.

10. The optoelectronic device according to claim 1, characterized in that, The thickness of the material layer is matched to the wavelength of the emitted light so that the dielectric reflector reflects the light of that wavelength.

11. The optoelectronic device according to claim 1, characterized in that, The dielectric reflector is designed as a Bragg mirror.

12. The optoelectronic device according to claim 1, further comprising: - A converter material on a light-emitting surface, wherein the converter material has an inorganic dye or quantum dots.

13. The optoelectronic device according to claim 1, further comprising: - Light-forming structures, especially photonic structures or microlenses, on the light-emitting surface.

14. The optoelectronic device according to claim 13, wherein, The light-forming structure has at least one of the following properties: - The light-shaped structure includes periodic regions with different refractive indices; - The photoforming structure includes a first region and a second region with different refractive indices; wherein, the converter material forms the first region; - The photoforming structure is formed at least partially in the semiconductor layer sequence.

15. A microdisplay device, a monolithic array, or a headlight device having multiple optoelectronic devices whose light sources are arranged in an array.

16. The micro display device according to claim 15, characterized in that, The light source of the optoelectronic device is embedded in the carrier. In particular, this method makes only the light-emitting surface of the light source represent the free outer surface, while the other interfaces of the light source are surrounded by the material of the carrier.

17. A method for manufacturing optoelectronic components, particularly display devices or headlights, wherein: A photoelectric light source based on semiconductor materials is provided, the light source having an active region for generating light and a light-emitting surface for emitting light generated on the upper side, and A dielectric reflector is disposed on the interface of the light source, preferably excluding the top side, and the reflector is designed to reflect the generated light. The interface confines the light source to the sides and / or downwards.

18. A method for manufacturing an optoelectronic device, particularly a display device or a headlight device, wherein, In this method, a light source consisting of multiple optoelectronic devices is arranged in an array and placed in the carrier, such that only the upper side of the light emitting surface of the light source represents the free outer surface, while the other materials of the carrier surround the interface of the light source.

19. A method for manufacturing a μ display, a monolithic array, or a headlight device, particularly a method having a plurality of optoelectronic devices according to claim 1, wherein in the method The optoelectronic light sources based on semiconductor materials are arrayed on the carrier, such that each light source has an active region for generating light and a free outer upper side that serves as a light emitting surface. in, A dielectric reflector is arranged on at least one interface for each light source, which, relative to the material of the carrier, defines the light source to the side and / or downwards, and is designed to reflect the light generated in the light source.

20. The method according to claim 1, characterized in that, Arranging dielectric reflectors involves applying material to the dielectric reflectors by means of atomic layer deposition.

21. The method according to claim 1, characterized in that, Arranging a dielectric reflector includes: arranging at least one layer of material for the dielectric reflector by a first method, and arranging material for other layers by a second method, wherein, preferably, the first method is a vapor deposition method, and the second method is preferably an atomic layer deposition method.

22. A method for manufacturing a μ display, particularly comprising a plurality of optoelectronic devices according to claim 1, wherein, In this method The optoelectronic light sources based on semiconductor materials are arranged in an array on the carrier, such that each light source has an active region for generating light and a free outer upper side that serves as a light emission surface. The light sources are arranged such that there is at least a tiny gap between adjacent light sources on the upper side, which has a middle space at the rear. Specifically, a dielectric reflector is arranged at at least one interface for each light source, which, relative to the material of the carrier, defines the light source to the side and / or downwards. The dielectric reflector is designed to reflect light generated in the light source. Among them, the dielectric reflector forming the light source is formed by introducing the material for the dielectric reflector from the top into the corresponding gap between adjacent light sources, especially by atomic layer deposition, and forming the dielectric reflector in the intermediate space behind the gap.

23. The method according to claim 22, characterized in that, At least the light-emitting surface of the light source is covered by a photomask, while a dielectric reflector is formed in the intermediate space.

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