Fourth pixel color in full color display device

Abstract

A light emitting diode (LED) array comprising: a plurality of pixels, each of the pixels comprising a respective group of light emitting diodes (LEDs), the plurality of pixels comprising: a first group of pixels configured to emit a first red primary wavelength; a second group of pixels configured to emit a first green primary wavelength; a third group of pixels configured to emit a first blue primary wavelength; the first red primary wavelength, the first green primary wavelength, and the first blue primary wavelength defining an RGB (red-green-blue) color gamut; and a fourth group of pixels configured to emit a non-white emission comprising a higher luminous efficacy than any of the first group of pixels or the third group of pixels to increase power efficiency of the device.

Description

Technical Field

[0001] Embodiments of this disclosure generally relate to light-emitting diodes (LEDs), including micro light-emitting diodes (uLEDs) and systems incorporating LEDs. The LEDs include red pixels, green pixels, and blue pixels, as well as a fourth pixel with higher efficiency having red or blue pixels, achieving a large color gamut while making the system highly efficient. Background Technology

[0002] Semiconductor light-emitting devices or light-emitting power devices (such as devices that emit ultraviolet (UV) or infrared (IR) light power), including light-emitting diodes, resonant cavity light-emitting diodes, vertical cavity laser diodes, and edge-emitting lasers, are among the most efficient light sources currently available.

[0003] High-intensity / brightness light-emitting devices capable of operating in the visible spectrum include group III-V semiconductors, particularly binary, ternary, and quaternary alloys of gallium, aluminum, indium, and nitrogen, also known as group III nitride materials. Typically, group III nitride light-emitting devices are fabricated by epitaxially growing stacks of semiconductor layers with varying compositions and dopant concentrations on growth substrates such as sapphire, silicon carbide, group III nitrides, or other suitable substrates using metal-organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), or other epitaxial techniques. Sapphire is frequently used as a growth substrate due to its widespread commercial availability and relative ease of use. The stacks grown on the growth substrate typically include one or more n-type layers doped with, for example, Si, formed on the substrate; light-emitting or active regions formed on the one or more n-type layers; and one or more p-type layers doped with, for example, Mg, formed on the active regions.

[0004] Various emerging display applications, including wearable devices, head-mounted displays, and large-area displays, require miniaturized chips composed of high-density arrays of microLEDs (μLEDs or uLEDs) with lateral dimensions as low as less than 100μm × 100μm. MicroLEDs (uLEDs) typically have dimensions of about 50μm in diameter or width and are used to fabricate color displays by closely aligning microLEDs of wavelengths including red, blue, and green.

[0005] To manufacture a full-color display using any technology, three different colors (typically red-green-blue, or RGB) are needed to synthesize various colors on the display. The area covered by these three selected colors on the CIE color chart is called the RGB color gamut. Energy / power efficiency is particularly important in mobile device applications, where efficient color synthesis is sought.

[0006] In the design of LEDs including uLEDs, it is necessary to improve and / or maximize power efficiency. Summary of the Invention

[0007] This article provides light-emitting diodes (LEDs), systems, devices, dies, and arrays with LEDs.

[0008] One aspect provides a light-emitting diode (LED) system, including: a display including a plurality of pixels, each of the pixels including a corresponding group of light-emitting diodes (LEDs), the plurality of pixels including: a first group of pixels configured to emit a first red dominant wavelength; a second group of pixels configured to emit a first green dominant wavelength; a third group of pixels configured to emit a first blue dominant wavelength; the first red dominant wavelength, the first green dominant wavelength, and the first blue dominant wavelength define an RGB (red-green-blue) color gamut; and a fourth group of pixels configured to emit non-white emission including luminous efficacy higher than that of either the first group of pixels or the third group of pixels, to increase the power efficiency of the device; and a controller configured to control the plurality of pixels individually and / or in groups.

[0009] On the other hand, the light-emitting diode (LED) array includes: a plurality of pixels, each of which includes a corresponding group of light-emitting diodes (LEDs); the plurality of pixels includes: a first group of pixels configured to emit a first red dominant wavelength; a second group of pixels configured to emit a first green dominant wavelength; a third group of pixels configured to emit a first blue dominant wavelength; the first red dominant wavelength, the first green dominant wavelength, and the first blue dominant wavelength define the RGB (red-green-blue) color gamut; and a fourth group of pixels configured to emit non-white emission including luminous efficacy higher than that of either the first or third pixel, to increase the power efficiency of the device.

[0010] On the other hand, there is a method for operating a display, the method comprising: determining an image to be presented on the display; driving a plurality of pixels to provide the image, each of the pixels including a corresponding group of light-emitting diodes (LEDs), the plurality of pixels including: a first group of pixels configured to emit a first red dominant wavelength; a second group of pixels configured to emit a first green dominant wavelength; a third group of pixels configured to emit a first blue dominant wavelength; the first red dominant wavelength, the first green dominant wavelength, and the first blue dominant wavelength defining an RGB (red-green-blue) color gamut; and a fourth group of pixels configured to emit non-white emission including a luminous efficacy higher than that of either the first or third pixel to increase the power efficiency of the device; and controlling individual pixels and / or groups of pixels of the plurality of pixels. Attached Figure Description

[0011] To gain a more detailed understanding of the features described above, reference can be made to embodiments of the present disclosure, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings are merely illustrative of typical embodiments of the present disclosure and should not be construed as limiting the scope of the disclosure, as other equivalent embodiments are permissible. In the various figures of the drawings, the embodiments described herein are shown by way of example rather than limitation, and similar reference numerals indicate similar elements. Unless indicated by scale, the drawings herein are not to scale.

[0012] Figure 1 It is the International Commission on Illumination (CIE) 1931 chromaticity diagram, “CIE 1931 Color Chart”, used to illustrate the color gamut and the embodiments described herein; Figures 2-3 This is a schematic diagram showing a cross-section of a vertically stacked epitaxial layer of an LED wafer according to various embodiments applicable to light-emitting diodes (LEDs); Figures 4-5 This is a schematic diagram showing a cross-section of an LED having an electrical scheme according to various embodiments; Figures 6-7 This is a schematic diagram showing a top view of a lateral pixel arrangement according to various embodiments applicable to light-emitting diodes (LEDs); Figure 8 This is a schematic diagram showing a cross-section of a pixel in a downconversion system according to one or more embodiments; Figure 9 A top view of a uLED display device according to one or more embodiments is shown; Figure 10 It is a schematic diagram of a pixel driving circuit according to one or more embodiments; Figure 11 An exemplary display system including a uLED device according to embodiments of this document is schematically illustrated; and Figure 12 A block diagram of a visualization system according to one or more embodiments is shown. Detailed Implementation

[0013] Before describing several exemplary embodiments of this disclosure, it should be understood that this disclosure is not limited to the details of the construction or process steps set forth in the following description. This disclosure can have other embodiments and can be practiced or performed in various ways.

[0014] The term LED refers to a light-emitting diode that emits light when an electric current flows through it. In one or more embodiments, the LED described herein has one or more feature dimensions (e.g., height, width, depth, thickness, etc.) ranging from 75 micrometers or greater to 300 micrometers or less. The micrometers mentioned herein allow for variations of ±1-5%. In some cases, LEDs are referred to as microLEDs (uLEDs or μLEDs), referring to light-emitting diodes having one or more feature dimensions (e.g., height, width, depth, thickness, etc.) on the order of micrometers or tens of micrometers. In one or more embodiments, one or more of the dimensions of height, width, depth, and thickness have values ​​ranging from 1 to less than 75 micrometers, for example from 1 to 50 micrometers, or from 1 to 25 micrometers. Generally, in one or more embodiments, the LED described herein can have feature dimensions ranging from 1 micrometer to 300 micrometers, and all values ​​and subranges therebetween.

[0015] LEDs capable of operating in the visible spectrum include group III-V semiconductors, particularly binary, ternary, and quaternary alloys of gallium, aluminum, indium, and nitrogen, also known as group III nitride materials. Typically, group III nitride light-emitting devices are fabricated by epitaxially growing stacks of semiconductor layers with varying compositions and dopant concentrations on growth substrates such as sapphire, silicon carbide, group III nitrides, or other suitable substrates using metal-organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), or other epitaxial techniques. Sapphire is frequently used as a growth substrate due to its widespread commercial availability and relative ease of use. The stacks grown on the growth substrate typically include one or more n-type layers doped with, for example, Si, formed on the substrate; light-emitting or active regions formed on the one or more n-type layers; and one or more p-type layers doped with, for example, Mg, formed on the active regions. An LED die is a structure comprising a substrate and a stack of semiconductor layers.

[0016] Methods for depositing materials, layers, and thin films include, but are not limited to: sputtering deposition, atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma-enhanced atomic layer deposition (PEALD), plasma-enhanced chemical vapor deposition (PECVD), and combinations thereof.

[0017] A method for forming or growing a semiconductor layer comprising an n-type layer, an active region, and a p-type layer, according to methods known in the art. In one or more embodiments, the semiconductor layer is formed by epitaxial growth (EPI). The semiconductor layer according to one or more embodiments comprises an epitaxial layer, a group III nitride layer, or an epitaxial group III nitride layer. In one or more embodiments, the semiconductor layer comprises a group III nitride material, and in a specific embodiment, it comprises an epitaxial group III nitride material. In some embodiments, the group III nitride material comprises one or more of gallium (Ga), aluminum (Al), and indium (In). Thus, in some embodiments, the semiconductor layer comprises one or more of gallium nitride (GaN), aluminum nitride (AlN), indium nitride (InN), aluminum gallium nitride (AlGaN), indium gallium nitride (InGaN), indium aluminum nitride (InAlN), aluminum indium gallium nitride (AlInGaN), etc. Depending on whether a p-type or n-type group III nitride material is required, the group III nitride material may be doped with one or more of silicon (Si), oxygen (O), boron (B), phosphorus (P), germanium (Ge), manganese (Mn), or magnesium (Mg). In one or more embodiments, the semiconductor layer has a combined thickness in the range of about 2 μm to about 10 μm, and all values ​​and subranges therebetween.

[0018] According to one or more embodiments, the term "substrate" as used herein refers to an intermediate or final structure having a surface or a portion of a surface on which the process is performed. Furthermore, in some embodiments, reference to substrate also refers only to a portion of the substrate, unless the context clearly indicates otherwise. Additionally, according to some embodiments, reference to deposition on a substrate includes deposition on a bare substrate, or deposition on a substrate on which one or more films, features, or materials are deposited or formed.

[0019] In one or more embodiments, "substrate" means any substrate on which a film treatment is performed during a manufacturing process, or a material surface formed on a substrate. In exemplary embodiments, depending on the application, the substrate surface on which the treatment is performed includes materials such as silicon, silicon oxide, silicon-on-insulator (SOI), strained silicon, amorphous silicon, doped silicon, carbon-doped silicon oxide, germanium, gallium arsenide, glass, sapphire, and any other suitable materials such as metals, metal nitrides, III-nitrides (e.g., GaN, AlN, InN, and alloys), metal alloys, and other conductive materials, metal phosphides (e.g., InP). Substrates include, but are not limited to, light-emitting diode (LED) devices. In some embodiments, the substrate is exposed to pretreatment processes to polish, etch, reduce, oxidize, hydroxylate, anneal, UV cure, electron beam cure, and / or bake the substrate surface. In addition to performing the film treatment directly on the surface of the substrate itself, in some embodiments, any of the disclosed film treatment steps are also performed on a sublayer formed on the substrate, and the term "substrate surface" is intended to include such a sublayer as indicated by the context. Therefore, for example, in the case where a film / layer or part of a film / layer has been deposited on the substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface.

[0020] The terms “wafer” and “substrate” will be used interchangeably in this disclosure. Thus, as used herein, a wafer is used as a substrate for forming the LED device described herein.

[0021] Examples of different implementations of light-emitting diodes (LEDs) will be described more fully below with reference to the accompanying drawings. These examples are not mutually exclusive, and features found in one example may be combined with features found in one or more other examples to achieve additional implementations. Therefore, it will be understood that the examples shown in the drawings are provided for illustrative purposes only and are not intended to limit this disclosure in any way. The same numerals always denote the same elements.

[0022] LED devices can include light-emitting diodes, resonant cavity light-emitting diodes, vertical cavity laser diodes, edge-emitting lasers, etc. (collectively, "LEDs"). Due to their compact size and low power requirements, LEDs can be attractive candidates for many different applications. They can be used as light sources (e.g., flashlights and camera flashes) in handheld battery-powered devices such as cameras and mobile phones. They can also be used, for example, in automotive lighting, head-up display (HUD) lighting, garden lighting, street lighting, video flashlights, general lighting (e.g., home, shop, office, and studio lighting, theater / stage lighting, and architectural lighting), augmented reality (AR) lighting, virtual reality (VR) lighting, as backlights for displays, and in the IR spectrum. Multi-junction devices or LED arrays (e.g., monolithic LED arrays, micro-LED arrays, etc.) can be used for applications that expect or require higher brightness.

[0023] For monitors, a large RGB color gamut is preferred to allow for enhanced display performance. Figure 1 This is the International Commission on Illumination (CIE) 1931 chromaticity diagram, “CIE 1931 Color Chart” 500, used to illustrate the color gamut and embodiments described herein. The CIE is an international standards organization that creates standards related to light and color. The CIE 1931 color space defines the quantitative relationship between the distribution of wavelengths in the visible spectrum and physiologically perceived color in human color vision. The mathematical relationships defining the CIE color space are used as a tool for color management related to lighting displays. Chromaticity is an objective specification of color quality, independent of its luminance. Chromaticity consists of two independent parameters, typically specified as hue and chroma (which are also alternatively referred to as saturation, chromaticity, intensity, or color purity). Figure 1 The chromaticity map 500 is a normalized map for a standard observer. For this map, each point corresponds to the color response of a CIE 1931 standard observer and represents a mapping of human color perception based on two CIE parameters, x and y.

[0024] LED displays typically use light-emitting diodes (LEDs) of three primary colors: red, green, and blue. For example... Figure 1 As shown in Figure 500, the color gamut is defined by triangle 501, which is represented by a given set of RGB points, for example, the red coordinates at point 502, the green coordinates at point 504, and the blue coordinates at point 506. For illustrative purposes, referring to the (x, y) coordinates in Figure 500, the red coordinates at point 502 are (0.64, 0.33), the green coordinates at point 504 are (0.30, 0.60), and the blue coordinates at point 506 are (0.15 and 0.06). The colors within triangle 501 can be produced by balancing the flux of the primary colors. White point 508 is located within triangle 501.

[0025] The red-green trajectory 510 is defined by one side of triangle 501 between red point 502 and green point 504, and the blue-green trajectory 512 is defined by the other side of triangle 501 between blue point 506 and green point 504.

[0026] For a large RGB color gamut, in addition to an appropriate selection of the dominant green wavelength, relatively deep reds (i.e., longer dominant wavelengths) and relatively deep blues (i.e., shorter dominant wavelengths) are also chosen. Relatively deep reds and deeper blues have low luminous efficacy; however, this results in low system efficiency. If higher luminous efficacy reds and / or blues are used in the RGB color gamut, the color gamut shrinks accordingly, which is not preferable. Using these low-efficiency reds and blues to synthesize unsaturated colors is particularly inefficient because it requires more effort to drive the red and blue pixels. LED emitters typically do not have sufficient flexibility to adjust the color purity (color saturation) of their light emission.

[0027] This disclosure resolves the conflict between providing a wider color gamut and a more efficient display device. By including a fourth pixel with higher luminous efficacy in either red or blue, a wide color gamut is achieved while maintaining high system power efficiency. Therefore, the LED chips, arrays, devices, and systems of this invention include a fourth pixel with higher luminous efficacy than one of the RGB points that define the color gamut. "Luminous efficacy" refers to a measure of luminous flux (or light output) versus power (lm / W). The luminous efficacy function is a way of conveying the spectral sensitivity of a viewer's visual perception of light. A color or emission with luminous efficacy higher than either the gamut-defined red or the gamut-defined blue means that the emitted color is more easily perceived by a viewer compared to a color with lower luminous efficacy.

[0028] In one or more embodiments, the fourth group of pixels is configured to emit a non-white emission. In one or more embodiments, the fourth group of pixels is configured to emit a non-yellow emission or a non-amber emission.

[0029] about Figure 1 An exemplary high luminous efficacy color, defined by the color gamut of red relative to point 502, is located at point 514 with coordinates (0.60, 0.36). In one or more embodiments, the high efficacy red can be in the range of 0.50 ≤ x ≤ 0.65 and 0.25 ≤ y ≤ 0.45. An exemplary high luminous efficacy color, defined by the color gamut of blue relative to point 506, is located at point 516 with coordinates (0.12, 0.14). In one or more embodiments, the high efficacy blue can be in the range of 0.10 ≤ x ≤ 0.25 and 0.10 ≤ y ≤ 0.25.

[0030] In one or more embodiments, the fourth pixel is configured to emit a wavelength shorter than that of the color gamut-defined red or any wavelength longer than that of the color gamut-defined blue. Thus, as a non-limiting example, such as Figure 1 As shown, if the dominant wavelengths of red and blue are 615 nm and 465 nm respectively in a typical display, then the dominant wavelength of the fourth pixel can be chosen as 600 nm or 475 nm.

[0031] Point 518, with exemplary coordinates (0.43, 0.53), is the complementary color to the dominant blue wavelength, such as a color in the green-yellow range (dominant wavelength ~570 nm), which will be synthesized into white simply by mixing blue and a fourth pixel configured with the complementary color accordingly. In this way, green and red (GR) pixels will not be powered, thus contributing to power efficiency. In one or more embodiments, the complementary yellow-green can be in the range of 0.35 ≤ x ≤ 0.50 and 0.40 ≤ y ≤ 0.55.

[0032] For gamut-defined RGB points, in one or more embodiments, the red coordinates are in the range of 0.64 ≤ x ≤ 0.67 and y = 0.33; the green coordinates are in the range of 0.21 ≤ x ≤ 0.30 and 0.60 ≤ y ≤ 0.71; and the blue coordinates are in the range of 0.14 ≤ x ≤ 0.15 and 0.06 ≤ y ≤ 0.08. In one or more embodiments, the gamut-defined RGB includes a dominant red wavelength in the range of 610 to 630 nm; a dominant green wavelength in the range of 530 to 555 nm; and a dominant blue wavelength in the range of 465 to 470 nm.

[0033] The aspects of this disclosure can be applied to color-filtered full-color displays excited by white light sources (e.g., LCD, LCOS). Advantageously, the aspects of this disclosure can also be applied to direct-color emitter displays, such as LED displays comprising horizontally arranged pixels and vertically stacked multi-color emitters (uLEDs).

[0034] In uLED display devices, the integration of a fourth pixel is a technique to enhance color synthesis, but processing challenges must be considered. Mass transfer technology for uLED chips is developing, but commercial focus is on the die-attach speed of handling millions of RGB chips per display device. Adding a fourth chip for the fourth pixel could significantly complicate the process. One possible solution is to utilize vertically stacked multicolor LED chips, including tunnel junctions, and add an epitaxial stack layer for the fourth pixel, which is expected to add a very small amount of epitaxial time, with die fabrication completed using conventional techniques. In this way, the uLED chip incorporates the fourth pixel without adding any additional time to the mass transfer die-attachment, or, when the EPI chip is monolithically integrated with the backplane, substantially no increase in processing time per display device. Therefore, this disclosure is considered particularly advantageous for uLED display applications.

[0035] LEDs themselves do not offer much flexibility in adjusting color purity (color saturation). In addition to dominant wavelength conversion, phosphor-converted LEDs (pc-LEDs) typically provide flexibility in color purity. Both LEDs and pc-LEDs are suitable for implementing aspects of this disclosure to include the four types of pixels discussed herein.

[0036] LED chips and arrays Figures 2-3 This is a schematic diagram showing a cross-section of a vertically stacked epitaxial layer (or epitaxial layer) of an LED wafer or die according to various embodiments applicable to light-emitting diodes (LEDs) having four types of pixels. Figures 2-3 The LED chips or dies 100A and 100B are multi-colored with a vertical configuration because they include one or more tunnel junctions, such that a first LED group including microLEDs is configured to emit a first dominant red wavelength, a second LED group including microLEDs is configured to emit a first dominant green wavelength, a third LED group including microLEDs is configured to emit a first dominant blue wavelength, and a fourth LED group including microLEDs is configured to emit a non-white emission. In one or more embodiments, the non-white emission is emitted as a second dominant red wavelength or a second dominant blue wavelength.

[0037] Figures 2-3 The LED chips or dies 100A and 100B include four light-emitting stacks or pn junctions: a first light-emitting stack 105a, a second light-emitting stack 105b, a third light-emitting stack 105c, and a fourth light-emitting stack 105d. In one or more embodiments, the first light-emitting stack 105a includes a first active light-emitting region 106a configured to emit a first dominant red wavelength when a current is applied, the second light-emitting stack 105b includes a second active light-emitting region 106b configured to emit a first dominant green wavelength when a current is applied, and the third light-emitting stack 105c includes a third active light-emitting region 106c configured to emit a first dominant blue wavelength when a current is applied. Therefore, the first light-emitting stack 105a, the second light-emitting stack 105b, and the third light-emitting stack 105c together define the RGB color gamut when a current is applied, and the fourth light-emitting stack 105d provides light emission with higher luminous efficacy than either the first or third light-emitting stack. In one or more embodiments, a fourth light-emitting stack 105d is used to provide a fourth group of pixels configured to emit non-white emission, which includes higher luminous efficacy than either a first pixel provided by a first light-emitting stack 105a or a third pixel provided by a third light-emitting stack 105c.

[0038] Go to Figure 2On the substrate 102 (e.g., a growth substrate) of the LED chip 100A is a first light-emitting stack 105a, which includes: a first n-type layer 104a, a first light-emitting active region 106a grown on the first n-type layer 104a, and a first p-type layer 108a formed on the first light-emitting active region 106a. A first tunnel junction 110a located on the first p-type layer 108a and below the second n-type layer 104b separates the first light-emitting stack 105a from the second light-emitting stack 105b.

[0039] The second light-emitting stack 105b includes: a second n-type layer 104b, a second light-emitting active region 106b grown on the second n-type layer 104b, and a second p-type layer 108b formed on the second light-emitting active region 106b. A second tunnel junction 110b located on the second p-type layer 108b and below the fourth p-type layer 104d separates the second light-emitting stack 105b from the fourth light-emitting stack 105d.

[0040] In an embodiment of LED chip 100A, the fourth light-emitting stack 105d is directly above the second light-emitting stack 105b. The fourth light-emitting stack 105d includes: a fourth n-type layer 104d, a fourth active light-emitting region 106d grown on the fourth n-type layer 104d, and a fourth p-type layer 108d formed on the fourth active light-emitting region 106d. A third tunnel junction 110c located on the fourth p-type layer 108d and below the third n-type layer 104c separates the fourth light-emitting stack 105d from the third light-emitting stack 105c.

[0041] The third light-emitting stack 105c is located above all the first light-emitting stacks 105a, 105b, and 105d, and directly above the fourth light-emitting stack 105d. The third light-emitting stack 105c includes: a third n-type layer 104c, a third active light-emitting region 106c grown on the third n-type layer 104c, and a third p-type layer 108c formed on the third active light-emitting region 106c. In this embodiment, the fourth light-emitting stack 105d is configured to emit high-efficiency blue light, with higher luminous efficacy than the third light-emitting stack 105c.

[0042] exist Figure 3 In the LED chip 100B, on the substrate 102 (e.g., a growth substrate), there is a first light-emitting stack 105a, which includes: a first n-type layer 104a, a first light-emitting active region 106a grown on the first n-type layer 104a, and a first p-type layer 108a formed on the first light-emitting active region 106a. A first tunnel junction 110a located on the first p-type layer 108a and below the fourth n-type layer 104d separates the first light-emitting stack 105a from the fourth light-emitting stack 105d.

[0043] In an embodiment of LED chip 100B, the fourth light-emitting stack 105d is directly above the first light-emitting stack 105a. The fourth light-emitting stack 105d includes: a fourth n-type layer 104d, a fourth active light-emitting region 106d grown on the fourth n-type layer 104d, and a fourth p-type layer 108d formed on the fourth active light-emitting region 106d. A second tunnel junction 110b located on the fourth p-type layer 108d and below the second n-type layer 104b separates the fourth light-emitting stack 105d from the second light-emitting stack 105b.

[0044] The second light-emitting stack 105b, directly above the fourth light-emitting stack 105d, includes: a second n-type layer 104b, a second active light-emitting region 106b grown on the second n-type layer 104b, and a second p-type layer 108b formed on the second active light-emitting region 106b. A third tunnel junction 110c, located on the second p-type layer 108b and below the third p-type layer 104c, separates the second light-emitting stack 105b from the third light-emitting stack 105c.

[0045] The third light-emitting stack 105c is located above all the first light-emitting stacks 105a, the second light-emitting stack 105b, and the fourth light-emitting stack 105d, and is directly above the second light-emitting stack 105b. The third light-emitting stack 105c includes: a third n-type layer 104c, a third light-emitting active region 106c grown on the third n-type layer 104c, and a third p-type layer 108c formed on the third light-emitting active region 106c.

[0046] In some embodiments, the fourth light-emitting stack 105d is configured to emit high-efficiency red light, which has higher luminous efficacy than the first light-emitting stack 105a.

[0047] In other embodiments, the fourth light-emitting stack 105d is configured to emit complementary blue light with higher luminous efficacy than the first light-emitting stack 105a, and produces white light when combined with the third light-emitting stack 105c.

[0048] Figures 4-5 This is a schematic diagram showing a cross-section of an exemplary LED with an electrical scheme, which can utilize, for example... Figures 2-3 The epitaxial stack. The vertical stack can have a mesa structure or a through-hole structure. In a through-hole structure, all vertical regions remain active. In a mesa structure, the vertical overlapping regions are deactivated, or the p-electrode regions are confined to where light emission is required. For illustrative purposes, a device circuit is shown. Figure 2 LED chips.

[0049] Providing a countertop structure Figure 4 In China, according to Figure 2LED chips or dies are appropriately fabricated to create mesa from the stack and optical isolation as needed, as well as electrical contacts and connections, which form the basis of the LED array. A first light-emitting stack 105a has been fabricated to connect a first n-type layer 104a to a device circuit 101A comprising a plurality of pixel current source / driver transistors 124a, 124b, 124d, 124c via a connection line 120. A first p-type layer 108a is exposed and fabricated with contacts, and is included in the circuit 101A via contact connection line 122a. A first pixel driver 124a is used in conjunction with the first light-emitting stack 105a and a first pixel circuit. A second p-type layer 108b is exposed and fabricated with contacts, and is included in the circuit 101A via contact connection line 122b. A second pixel driver 124b is used in conjunction with a second light-emitting stack 105b and a second pixel circuit. A fourth p-type layer 108d is exposed and fabricated with contacts, and is included in the circuit 101A via contact connection line 122d. The fourth pixel driver 124d is used in conjunction with the fourth light-emitting stack 105d and the fourth pixel circuitry. The third p-type layer 108c is exposed and fabricated with contacts, and is included in circuitry 101A via contact connection lines 122c. The third pixel driver 124c is used in conjunction with the third light-emitting stack 105c and the third pixel circuitry. A controller 125 is included in circuitry 101A. The controller is configured to control multiple pixels individually and / or in groups.

[0050] Providing through-hole structures Figure 5 middle, Figure 2 The LED wafers or dies are fabricated with electrical contacts and connections, forming the basis of the LED array. The first light-emitting stack 105a has been fabricated to connect the first n-type layer 104a to a device circuit 101B, which includes multiple pixel current sources / drivers 124a, 124b, 124d, and 124c, via connection lines 120. Figure 2The LED chip is fabricated to create multiple contact openings / vias 126a, 126b, 126d and corresponding electrode connections 123a, 123b, 123d to create contacts with the respective p-type layers. Electrode connections 123c contact the p-type layer 108c without any contact openings / vias. A first p-type layer 108a is included in circuit 101B via the first contact opening / electrode connection 123a. A first pixel driver 124a is used in conjunction with a first light-emitting stack 105a. A second p-type layer 108b is included in circuit 101B via the second contact opening / electrode connection 123b. A second pixel driver 124b is used in conjunction with a second light-emitting stack 105b. A fourth p-type layer 108d is included in circuit 101B via the fourth contact opening / electrode line 123d. A fourth pixel driver 124d is used in conjunction with a fourth light-emitting stack 105d. The third p-type layer 108c is included in circuit 101B via the second contact opening / electrode connection line 123c. The third pixel driver 124c is used in conjunction with the third light-emitting stack 105c. Controller 130 is included in circuit 101B. The controller is configured to control multiple pixels individually and / or in groups.

[0051] Figures 6-7 This is a schematic top view illustrating a lateral pixel arrangement according to various embodiments applicable to light-emitting diodes (LEDs). Figures 6-7 In this configuration, multiple LEDs, including uLED, comprise four groups of pixels. The first group of pixels, 152, is configured to emit a first dominant red wavelength. The second group of pixels, 154, is configured to emit a first dominant green wavelength. The third group of pixels, 156, is configured to emit a first dominant blue wavelength. The first dominant red wavelength, the first dominant green wavelength, and the first dominant blue wavelength define the RGB (red-green-blue) color gamut.

[0052] exist Figure 6 In the middle, the fourth group of pixels 158 is configured to emit non-white light, which includes higher luminous efficacy than the third group of pixels, similar to Figure 2 .

[0053] exist Figure 7 In the middle, the fourth group of pixels 162 is configured to emit non-white light, which includes higher luminous efficacy than the first group of pixels, similar to Figure 3 .

[0054] In some embodiments, the fourth group of pixels 162 is configured to emit high-efficiency red light, which has higher luminous efficacy than the first group of pixels 152.

[0055] In other embodiments, the fourth group of pixels 162 is configured to emit complementary blue light, which is more luminous than the first group of pixels 152, and produces white light when combined with the third group of pixels 156.

[0056] The embodiments described herein include: vertically stacked epitaxial wafers or dies with RGB+X (where X is high-efficiency red); vertically stacked epitaxial wafers with RGB+X (where X is high-efficiency blue); and vertically stacked epitaxial wafers with RGB+X (where X is yellow-green).

[0057] In one or more embodiments, wafer processing is applied to vertically stacked epitaxial wafers or dies to produce multicolor uLED chips. In one or more embodiments, any multicolor uLED chip described herein is mass-transferred to a display substrate to complete the display unit.

[0058] In one or more embodiments, wafer processing is applied to vertically stacked epitaxial wafers or dies to produce a multicolor uLED array. In one or more embodiments, any multicolor uLED array described herein is then attached to a backplane to complete the display unit.

[0059] exist Figure 8 In the process, the down-converter configuration of the LED chip or die 200 includes four light-emitting regions: a first light-emitting region 205a, a second light-emitting region 205b, a third light-emitting region 205c, and a fourth light-emitting region 205d.

[0060] LED chip 200 includes an n-type layer 104 on a substrate 102 (e.g., a growth substrate), a blue emitting active region 106 grown on the n-type layer 104a, and a p-type layer 108 formed on the blue emitting active region 106. A first light-emitting region 205a includes a first down-converter material 212a, such that when a current is applied, the first light-emitting region 205a emits a first red dominant wavelength. A second light-emitting region 205b includes a second down-converter material 212b, such that when a current is applied, the second light-emitting region 205b emits a first green dominant wavelength. A third light-emitting region 205c does not include a down-converter material, and when a current is applied, the third light-emitting region 205c emits a first blue dominant wavelength. A fourth light-emitting region 205d includes a third down-converter material 212d, such that when a current is applied, the fourth light-emitting region 205d emits a non-white emission. Therefore, the first light-emitting region 205a, the second light-emitting stack 505b, and the third light-emitting stack 205c together define the RGB color gamut when current is applied, and the fourth light-emitting region 205d provides light emission with higher luminous efficiency than the first light-emitting region 205a or the third light-emitting region 205c.

[0061] An LED according to one or more embodiments includes: a phosphor-converting LED, including a microLED, having a blue emitting region configured to emit a first dominant blue wavelength and three different down-converter materials on the blue emitting region, wherein a first down-converter material configured with the blue emitting region is used to emit a first dominant green wavelength, a second down-converter material configured with the blue emitting region is used to emit a first dominant red wavelength, and a third down-converter material configured with the blue emitting region is used to emit a second dominant red wavelength or a second dominant blue wavelength. In one or more embodiments, an LED array includes a down-converter configuration comprising a plurality of LEDs having a blue emitting region configured to emit a first dominant blue wavelength and three different down-converter materials on the blue emitting region, wherein a first down-converter material configured with the blue emitting region is used to emit a first dominant green wavelength, a second down-converter material configured with the blue emitting region is used to emit a first dominant red wavelength, and a third down-converter material configured with the blue emitting region is used to emit a second dominant red wavelength or a second dominant blue wavelength.

[0062] Subsequently, appropriate preparations were made according to... Figure 8 LED wafers or dies are used to create mesa and optical isolation, as well as electrical contacts and connections, as needed. In one or more embodiments, wafer processing is applied to a down-converter configuration of the LED wafers or dies, resulting in an LED array including a uLED array or an LED chip including uLED chips. In one or more embodiments, any down-converter configuration uLED chips described herein are then attached to a device substrate via mass transfer to complete the display unit. In one or more embodiments, any down-converter configuration uLED array described herein is then attached to a backplane to complete the display unit.

[0063] Figure 9 A top view of an exemplary uLED monolithic array 800 comprising a plurality of pixels arranged in a 6×19 grid is shown. Pixels 855a, 855b, 855c, and 855d are four different groups of pixels configured to emit different wavelengths and colors. In this embodiment, a common cathode 840 is connected to the pixels. An anode (not shown) is present on the underside of each pixel. In one or more embodiments, the array comprises an arrangement of 2×2 mesa, 4×4 mesa, 20×20 mesa, 50×50 mesa, 100×100 mesa, or n1×n2 mesa, wherein each of n1 and n2 is a number in the range of 2 to 1000, and n1 and n2 may be equal or unequal.

[0064] In one or more embodiments, a microLED (μLED or uLED) array is used. MicroLEDs can support high-density pixels with a lateral dimension of less than 100μm × 100μm. In some embodiments, microLEDs with a diameter or width dimension of approximately 50μm or less can be used. By aligning microLEDs, including red, blue, and green wavelengths, very closely together, these microLEDs can be used to manufacture color displays.

[0065] In some embodiments, the light-emitting array comprises a small number of microLEDs positioned on a substrate with an area of ​​centimeters or larger. In some embodiments, the light-emitting array comprises a microLED pixel array, wherein hundreds, thousands, or millions of light-emitting LEDs are positioned together on a substrate with an area of ​​centimeters or smaller. In some embodiments, the microLEDs may comprise light-emitting diodes with a size between 30 micrometers and 500 micrometers. The light-emitting array (one or more) may be monochromatic, RGB, or other desired chromaticity. In some embodiments, pixels may be square, rectangular, hexagonal, or have curved perimeters. Pixels may be of the same size, different sizes, or similar sizes and may be grouped to present a larger effective pixel size.

[0066] In some embodiments, the light-emitting pixels and the circuitry supporting the light-emitting array are packaged and optionally include a sub-base or printed circuit board connected to provide power to the semiconductor LEDs and control their light emission. In some embodiments, the printed circuit board supporting the light-emitting array includes vias, heat sinks, ground planes, traces, and flip-chip or other mounting systems. The sub-base or printed circuit board can be formed from any suitable material, such as ceramic, silicon, aluminum, etc. If the sub-base material is conductive, an insulating layer is formed on the substrate material, and a pattern of metal electrodes is formed on the insulating layer. The sub-base can serve as a mechanical support, provide an electrical interface between the electrodes on the light-emitting array and the power supply, and also provide heat dissipation.

[0067] In some embodiments, the LED light-emitting array includes optical elements, such as lenses, element lenses, and / or pre-collimators. The optical elements may also, or alternatively, include apertures, filters, Fresnel lenses, convex lenses, concave lenses, or any other suitable optical elements that affect the projected light from the light-emitting array. Additionally, one or more optical elements may have one or more coatings, including UV-blocking or anti-reflective coatings. In some embodiments, the optics can be used to correct or minimize two-dimensional or three-dimensional optical errors, including pincushion distortion, barrel distortion, longitudinal chromatic aberration, spherical aberration, chromatic aberration, field curvature, astigmatism, or any other type of optical error. In some embodiments, the optical elements can be used to magnify and / or correct images. Advantageously, in some embodiments, magnifying the displayed image allows the light-emitting array to be physically smaller, lighter, and require less power compared to a larger display. Additionally, magnification can increase the field of view of the displayed content, thereby allowing the display to present a field of view equal to the user's normal field of view.

[0068] In one or more embodiments, the light-emitting diode (LED) array includes: a plurality of pixels, each of which includes a corresponding group of light-emitting diodes (LEDs); the plurality of pixels includes: a first group of pixels configured to emit a first red dominant wavelength; a second group of pixels configured to emit a first green dominant wavelength; a third group of pixels configured to emit a first blue dominant wavelength; the first red dominant wavelength, the first green dominant wavelength, and the first blue dominant wavelength define an RGB (red-green-blue) color gamut; and a fourth group of pixels configured to emit non-white emission including luminous efficacy higher than that of either the first or third pixel, to increase the power efficiency of the device.

[0069] In one embodiment, the LED includes multicolor microLEDs, wherein at least a portion of the multicolor microLEDs includes one or more tunnel junctions, such that a first group of microLEDs is configured to emit a first red dominant wavelength, a second group of microLEDs is configured to emit a first green dominant wavelength, a third group of microLEDs is configured to emit a first blue dominant wavelength, and a fourth group of microLEDs is configured to emit a non-white emission as a second red dominant wavelength or a second blue dominant wavelength. A detailed embodiment provides a microLED comprising a vertically stacked configuration of microLEDs, the microLED comprising: a first epitaxial stack including: a first active region on a first n-type layer and a first p-type layer on the first active region; a second epitaxial stack including: a second active region on a second n-type layer and a second p-type layer on the second active region; a third epitaxial stack including: a third active region on a third n-type layer and a third p-type layer on the third active region; a fourth epitaxial stack including: a fourth active region on a fourth n-type layer and a fourth p-type layer on the fourth active region; and a first tunnel junction adjacent to the first epitaxial stack, a second tunnel junction adjacent to the second epitaxial stack, and a third tunnel junction adjacent to the third epitaxial stack; wherein the first, second, third, and fourth epitaxial stacks are vertically related within at least one set of pixels.

[0070] In some embodiments, a third epitaxial stack is placed above a second epitaxial stack; a second epitaxial stack is placed above a first epitaxial stack; a first tunnel junction separates the first and second epitaxial stacks; a fourth epitaxial stack is placed above the second epitaxial stack and below the third epitaxial stack, the second and fourth epitaxial stacks are separated by a second tunnel junction, and the fourth and third epitaxial stacks are separated by a third tunnel junction; and the fourth epitaxial stack is configured to emit a non-white emission with a wavelength greater than a first blue wavelength. In other embodiments, a third epitaxial stack is placed above a second epitaxial stack; a second epitaxial stack is placed above a first epitaxial stack; a fourth epitaxial stack is placed above the first epitaxial stack and below the second epitaxial stack, the first and fourth epitaxial stacks are separated by a first tunnel junction, and the second and fourth epitaxial stacks are separated by a second tunnel junction; a third tunnel junction separates the second and third epitaxial stacks; and the fourth epitaxial stack is configured to emit a non-white emission with a wavelength less than a first red wavelength or greater than a first green wavelength.

[0071] In one or more embodiments, the LED array includes a down-converter configuration, wherein the LEDs include: phosphor-converted microLEDs, each microLED having a blue emission region configured to emit a first blue dominant wavelength and three different down-converter materials on the blue emission region, a first down-converter material configured with the blue emission region for emitting a first green dominant wavelength, a second down-converter material configured with the blue emission region for emitting a first red dominant wavelength, and a third down-converter material configured with the blue emission region for emitting non-white emission as a second red dominant wavelength or a second blue dominant wavelength.

[0072] In one embodiment, the LED is integrated onto a monolithic substrate. In another embodiment, the LED is an individual LED attached to a device substrate.

[0073] LED Display In terms of implementation, the LED display of this document includes four types of pixel groups. Each type of pixel includes sub-pixels. Each pixel includes a corresponding group of light-emitting diodes (LEDs). In one or more embodiments, the display is manufactured using red, green, and blue pixels and a fourth pixel with higher efficiency than the red and blue pixels. In one embodiment, the display includes: a first group of pixels configured to emit a first red dominant wavelength; a second group of pixels configured to emit a first green dominant wavelength; a third group of pixels configured to emit a first blue dominant wavelength; the first red dominant wavelength, the first green dominant wavelength, and the first blue dominant wavelength define the RGB (red-green-blue) color gamut; and a fourth group of pixels configured to emit non-white emission including luminous efficiency higher than either the first or third pixel. The presence of the fourth pixel increases the power efficiency of the device because, when, for example, synthesizing unsaturated colors, the higher-efficiency pixel utilizing less power can be used as needed.

[0074] In one or more embodiments, a light-emitting diode (LED) display includes a plurality of pixels, each pixel including a corresponding group of light-emitting diodes (LEDs), the plurality of pixels including: a first group of pixels configured to emit a first red dominant wavelength; a second group of pixels configured to emit a first green dominant wavelength; a third group of pixels configured to emit a first blue dominant wavelength; the first red dominant wavelength, the first green dominant wavelength, and the first blue dominant wavelength define an RGB (red-green-blue) color gamut; and a fourth group of pixels configured to emit non-white emission including luminous efficacy higher than that of either the first group of pixels or the third group of pixels, to increase the power efficiency of the device; and a controller configured to control the plurality of pixels individually and / or in groups.

[0075] In one embodiment, the fourth group of pixels is configured to emit a second red dominant wavelength or a second blue dominant wavelength. According to the LED system of Embodiment 2, the fourth group of pixels is configured to emit a dominant wavelength of 600±5 nm or 480±5 nm; and optionally: the first red dominant wavelength is in the range of 610 to 630 nm; the first green dominant wavelength is in the range of 530 to 555 nm; and the first blue dominant wavelength is in the range of 465 to 470 nm.

[0076] In one embodiment, the fourth group of pixels is configured to emit a dominant wavelength of 575±5 nm.

[0077] In one embodiment, the LED includes multicolor microLEDs, wherein at least a portion of the multicolor microLEDs includes one or more tunnel junctions, such that a first group of microLEDs is configured to emit a first red dominant wavelength, a second group of microLEDs is configured to emit a first green dominant wavelength, a third group of microLEDs is configured to emit a first blue dominant wavelength, and a fourth group of microLEDs is configured to emit a non-white emission as a second red dominant wavelength or a second blue dominant wavelength.

[0078] In one embodiment, the multicolor microLEDs have a vertical configuration, and the system is configured to short some tunnel junctions into shorted junctions during operation.

[0079] In one embodiment, the LED includes phosphor-converted microLEDs, each microLED having a blue emission region configured to emit a first blue dominant wavelength and three different downconverter materials on the blue emission region, the first downconverter material configured with the blue emission region for emitting a first green dominant wavelength, the second downconverter material configured with the blue emission region for emitting a first red dominant wavelength, and the third downconverter material configured with the blue emission region for emitting a second red dominant wavelength or a second blue dominant wavelength.

[0080] LED system The presence of a fourth pixel helps increase the power efficiency of devices and systems that include it.

[0081] The power consumption of a display system can be divided into three main parts: static power in the driver and LEDs, switching power in the driver and storage capacitors, and dynamic power in the digital core / logic circuitry. The static power consumption in the driver and LEDs is ~EQE*Eph / (Vds+Vf). Eph is similar to Vf. The higher Vds is relative to Vf, the lower the system efficiency.

[0082] The driving transistors require a minimum Vds to operate as a current source in saturation. Noise margin is needed. In the case of thin-film backplanes, another margin is added to prevent differences in threshold voltage and mobility between pixels. In display arrays, another margin must be added to prevent voltage differences between power rails and ground rails due to IR voltage drops in large arrays.

[0083] The driver circuit can typically exceed the static power dissipated in the LED, and reducing this will improve the system power efficiency.

[0084] In both PWM and PAM methods used for grayscale encoding, Vds is required to be higher than the Vds of the highest grayscale value. In both PWM and PAM methods used for grayscale encoding, Vds is required to be higher than the sum of the Vds of the colors that are active.

[0085] In a 4-uLED stack, Vds can become high, and methods to reduce Vds would be beneficial. High-voltage CMOS is a challenge in this technology, and keeping the voltage low provides additional benefits.

[0086] In one or more embodiments, even with four groups of pixels, three groups are driven at a time to achieve full color gamut using LEDs with higher efficiency and higher Vf. Vdd can be designed with the constraint that at most three LEDs will be on. The total voltage will not rise in the stack. In embodiments including a vertical stack configuration with tunnel junctions, one of the junctions is always selectively shorted. In another embodiment, the shorted junction is reverse biased to act as a photodetector to obtain some absorption loss.

[0087] In another embodiment, field-sequence driving is used (to avoid high-voltage CMOS). Advantageously, a high color gamut is achieved by turning on only two colors, which provides additional brightness benefits, since most color gamuts are achieved by time-division multiplexing only two colors. Most color gamuts can now be achieved using higher Vf, higher efficiency, and higher efficacy colors compared to lower Vf, lower efficiency, and lower efficacy red. Corresponding backplane power savings are also expected, which complement and may exceed the power savings from the efficacy gain of the LED itself.

[0088] Figure 10 A schematic diagram of a pixel driving circuit 1000 according to one or more embodiments is provided. The LED display described herein includes groups of four types of pixels, and each type of pixel includes sub-pixels. Figure 10In the schematic diagram, the main current source 1001 powers the pixel driving circuits 1000 of sub-pixels #1, #2, #3, and #4. Control #1 is active for controlling sub-pixel #1. Control #2 is active for controlling sub-pixel #2. Control #3 is active for controlling sub-pixel #3. Control #4 is active for controlling sub-pixel #4. In one or more embodiments, the pixel includes a multi-color microLED comprising one or more tunnel junctions. In one embodiment, the multi-color microLED comprises three tunnel junctions. In one or more embodiments, the control scheme includes shorting one of the three junctions during all operations, which is advantageous for reducing Vdd and increasing system power efficiency.

[0089] In one or more embodiments, a light-emitting diode (LED) system includes: any array or display herein; and a controller configured to control a plurality of pixels individually and / or in groups.

[0090] In one or more embodiments, a light-emitting diode (LED) system includes: a display including a plurality of pixels, each of the pixels including a corresponding group of light-emitting diodes (LEDs), the plurality of pixels including: a first group of pixels configured to emit a first red dominant wavelength; a second group of pixels configured to emit a first green dominant wavelength; a third group of pixels configured to emit a first blue dominant wavelength; the first red dominant wavelength, the first green dominant wavelength, and the first blue dominant wavelength define an RGB (red-green-blue) color gamut; and a fourth group of pixels configured to emit non-white emission including luminous efficacy higher than that of either the first group of pixels or the third group of pixels, to increase the power efficiency of the device; and a controller configured to control the plurality of pixels individually and / or in groups.

[0091] In one embodiment, the LED system is configured to drive no more than three groups of pixels during operation.

[0092] In one embodiment, the LED system includes a field-sequence drive configured to drive only two sets of pixels during operation.

[0093] In one embodiment, the LED system further includes a thin-film display backplane, a CMOS backplane, or a CMOS microIC configured to drive each group of pixels.

[0094] In one embodiment, the LED system includes one or more driver transistors configured as current sources for one or more pixel circuits.

[0095] In one embodiment, the LED system is configured to utilize reverse bias to control the shorting junction, and the shorting junction is effective as a photodetector.

[0096] application According to some embodiments, a method for operating a display includes: determining an image to be presented on the display; driving a plurality of pixels to provide the image, each of the pixels including a corresponding group of light-emitting diodes (LEDs), the plurality of pixels including: a first group of pixels configured to emit a first red dominant wavelength; a second group of pixels configured to emit a first green dominant wavelength; a third group of pixels configured to emit a first blue dominant wavelength; the first red dominant wavelength, the first green dominant wavelength, and the first blue dominant wavelength defining an RGB (red-green-blue) color gamut; and a fourth group of pixels configured to emit a non-white emission including a higher luminous efficacy than either the first or third pixel to increase the power efficiency of the device; and controlling individual pixels and / or groups of pixels. In a detailed embodiment, the fourth group of pixels is configured to emit a second red dominant wavelength or a second blue dominant wavelength.

[0097] Figure 11 An exemplary display system 900 utilizing LEDs including uLEDs disclosed herein is schematically illustrated. The display system 900 includes an LED light-emitting array 902 and a display 908 electrically connected to an LED driver 904. The display system 900 also includes a system controller 906, such as a microprocessor. The controller 906 is coupled to the LED driver 904. The controller 906 may also be coupled to the display 908 and optional sensors(s) 910, and is powered by a power supply 912. In one or more embodiments, user data input is provided to the system controller 906.

[0098] In one or more embodiments, the system is a camera flash system utilizing uLEDs. In such an embodiment, the LED light-emitting array 902 is an illumination array and lens system, and the display 908 includes a camera, wherein the LEDs of 902 and the camera of 908 can be controlled by a controller 906 to match their fields of view.

[0099] Optionally, the sensor 910 with control input may include, for example, a position sensor (e.g., a gyroscope and / or an accelerometer) and / or other sensors that can be used to determine the position, velocity, and orientation of the system. Signals from the sensor 910 may be provided to the controller 906 to determine the appropriate action of the controller 906 (e.g., which LEDs are currently illuminating the target, and which LEDs will illuminate the target after a predetermined amount of time).

[0100] In operation, the illumination from some or all of the pixels of the LED array in 902 can be adjusted—deactivated, operated at full intensity, or operated at intermediate intensity. As described above, the focusing or manipulation of the light beam emitted by the LED array in 902 can be electronically performed by activating one or more subsets of pixels to allow dynamic adjustment of the beam shape without moving the optics or changing the focus of the lenses in the illumination device.

[0101] LED array systems, such as those described herein, can support a variety of other applications that benefit from fine-grained intensity, spatial, and temporal control of light distribution. These applications can include, but are not limited to, precise spatial patterning of emitted light from pixel blocks or individual pixels. Depending on the application, the emitted light can be spectrally diverse, time-adaptive, and / or environmentally responsive. Emitting pixel arrays can provide pre-programmed light distributions with various intensities, spatial, or temporal patterns. The associated optics can differ at the pixel, pixel block, or device level. Example emitting pixel arrays may include devices with a common controlled central block of high-intensity pixels having associated common optics, while edge pixels may have individual optics. Common applications supported by emitting pixel arrays, besides flashlights, include video lighting, automotive headlights, architectural and area lighting, and street lighting.

[0102] Other applications of the LED devices described herein include augmented reality / virtual reality (AR / VR) systems that can utilize the uLEDs disclosed herein. One or more AR / VR systems include: augmented (AR) or virtual reality (VR) headsets, glasses, or projectors. Such AR / VR systems include LED light-emitting arrays, LED drivers (or light-emitting array controllers), system controllers, AR or VR displays, and sensor systems 810. Control inputs may be provided to the sensor system, while power and user data inputs are provided to the system controller. As will be understood, in some embodiments, the modules included in the AR / VR system may be compactly arranged in a single structure, or one or more components may be mounted separately and connected via wireless or wired communication. For example, the light-emitting array, AR or VR display, and sensor system may be mounted on a headset or glasses, with the LED driver and / or system controller mounted separately.

[0103] In one embodiment, the light-emitting array can be used to project light onto a pattern of graphics or objects capable of supporting an AR / VR system. In some embodiments, a separate light-emitting array can be used to provide a displayed image, wherein AR features are provided by different and separate microLED arrays. In some embodiments, selected groups of pixels can be used to display content to a user, while tracking pixels can be used to provide tracking light used in eye tracking. The content display pixels are designed to emit visible light having at least some portion of the visible band (approximately 400 nm to 750 nm). Conversely, the tracking pixels can emit light in the visible band or the IR band (approximately 750 nm to 2200 nm), or a combination thereof. As an alternative example, the tracking pixels can operate in the 800 to 1000 nanometer range. In some embodiments, the tracking pixels can emit tracking light during periods when the content pixels are turned off and no content is displayed to the user.

[0104] AR / VR systems can incorporate a wide range of optics into LED light-emitting arrays and / or AR / VR displays, for example, coupling light emitted by an LED light-emitting array into an AR / VR display as described above. For AR / VR applications, these optics may include nanofins and are designed to polarize the light they transmit.

[0105] In one embodiment, the emitting array controller can be used to provide power and real-time control for the emitting array. For example, the emitting array controller can achieve pixel-level or group-pixel-level control of amplitude and duty cycle. In some embodiments, the emitting array controller also includes a frame buffer for holding the generated or processed image that can be provided to the emitting array. Other supported modules may include digital control interfaces such as an inter-integrated circuit (I2C) serial bus, a serial peripheral interface (SPI), USB-C, HDMI, a display port, or other suitable image or control modules configured to transmit required image data, control data, or instructions.

[0106] In operation, pixels in an image can be used to define the response of the corresponding light-emitting array, where the intensity and spatial modulation of the LED pixels are based on one or more images. To mitigate data rate issues, in some embodiments, pixel groups (e.g., 5×5 blocks) can be controlled as a single block. In some embodiments, high-speed and high-data-rate operation is supported, where pixel values ​​from successive images can be loaded as consecutive frames in an image sequence at rates between 30 Hz and 100 Hz, with 60 Hz being typical. Pulse width modulation can be used to control each pixel to emit light in a manner at least in part dependent on the pattern and intensity of the image.

[0107] In some embodiments, the sensor system may include external sensors that monitor the environment, such as cameras, depth sensors, or audio sensors, and internal sensors that monitor the position of the AR / VR headset, such as accelerometers or two- or three-axis gyroscopes. Other sensors may include, but are not limited to, barometric pressure, stress, temperature, or any other suitable sensors required for local or remote environmental monitoring. In some embodiments, control input may include detected touches or taps, gesture input, or control based on the position of the headset or display. As another example, an estimated position of the AR / VR system relative to an initial position can be determined based on one or more measurement signals from one or more gyroscopes or position sensors that measure translational or rotational movement.

[0108] In some embodiments, the system controller uses data from the sensor system to integrate the measurement signal received from the accelerometer over time to estimate the velocity vector, and integrates the velocity vector over time to determine the estimated location of a reference point for the AR / VR system. In other embodiments, the reference point used to describe the location of the AR / VR system may be based on a depth sensor, a camera positioning view, or an optical flow.

[0109] Based on changes in the position, orientation, or movement of the AR / VR system, the system controller can send images or commands to the luminous array controller. Changes or modifications to images or commands can also be made as needed through user data input or automatic data input. User data input can include, but is not limited to, user data input provided by audio commands, haptic feedback, eye or pupil positioning, or connected keyboard, mouse, or game controllers.

[0110] Figure 12 A block diagram illustrating an example of a visualization system 10 is shown. The visualization system 10 may include a wearable housing 12, such as headphones or goggles. The housing 12 may mechanically support and house the elements detailed below. In some examples, one or more of the elements detailed below may be included in one or more additional housings, which may be detachable from the wearable housing 12 and may be wirelessly and / or coupled to the wearable housing 12 via a wired connection. For example, a separate housing may reduce the weight of the wearable goggles, such as by including batteries, wireless devices, and other components. The housing 12 may include one or more batteries 14, which may power any or all of the elements detailed below. The housing 12 may include circuitry capable of being electrically coupled to an external power source (e.g., a wall socket) to recharge the batteries 14. The housing 12 may include one or more wireless devices 16 for wireless communication with a server or network via a suitable protocol (e.g., WiFi).

[0111] The visualization system 10 may include one or more sensors 18, such as optical sensors, audio sensors, tactile sensors, thermal sensors, gyroscope sensors, time-of-flight sensors, triangulation-based sensors, etc. In some examples, one or more of the sensors may sense the user's position, orientation, and / or orientation. In some examples, one or more of the sensors 18 may generate sensor signals in response to the sensed position, orientation, and / or orientation. The sensor signals may include sensor data corresponding to the sensed position, orientation, and / or orientation. For example, the sensor data may include a depth map of the surrounding environment. In some examples, such as for augmented reality systems, one or more of the sensors 18 may capture real-time video images of the user's surrounding environment.

[0112] The visualization system 10 may include one or more video generation processors 20. The one or more video generation processors 20 may receive scene data representing a three-dimensional scene from a server and / or storage medium, such as a set of position coordinates of objects in the scene or a depth map of the scene. The one or more video generation processors 20 may receive one or more sensor signals from one or more sensors 18. In response to scene data representing the surrounding environment and at least one sensor signal representing the user's position and / or orientation relative to the surrounding environment, the one or more video generation processors 20 may generate at least one video signal corresponding to a view of the scene. In some examples, the one or more video generation processors 20 may generate two video signals, one for each of the user's eyes, representing views of the scene from the user's left and right eye viewpoints, respectively. In some examples, the one or more video generation processors 20 may generate more than two video signals and combine the video signals to provide one video signal for each eye, two video signals for each eye, or other combinations.

[0113] The visualization system 10 may include one or more light sources 22 that can provide light to the display of the visualization system 10. Suitable light sources 22 may include light-emitting diodes (LEDs), monolithic LEDs, multiple LEDs, LED arrays, LED arrays disposed on a common substrate, segmented LEDs disposed on a single substrate and having LED elements that can be individually addressed and controlled (and / or grouped and / or subset controlled), micro LED arrays, etc.

[0114] A light-emitting diode (LED) can be a white LED. For example, a white LED can emit excitation light, such as blue or violet light. A white LED may include one or more phosphors that can absorb some or all of the excitation light and can emit phosphor light with a wavelength longer than the excitation light in response, such as yellow light.

[0115] One or more light sources 22 may include light-generating elements with different colors or wavelengths. For example, the light source may include a red light-emitting diode capable of emitting red light, a green light-emitting diode capable of emitting green light, and a blue light-emitting diode capable of emitting blue light. Red, green, and blue light are combined in specific proportions to produce any suitable color that is visually perceptible in the visible portion of the electromagnetic spectrum.

[0116] The visualization system 10 may include one or more modulators 24. The modulators 24 may be implemented in at least one of two configurations.

[0117] In a first configuration, modulator 24 may include circuitry capable of directly modulating light source 22. For example, light source 22 may include an array of light-emitting diodes (LEDs), and modulator 24 may directly modulate the electrical power, voltage, and / or current directed to each LED in the array to form modulated light. Modulation may be performed in an analog and / or digital manner. In some examples, light source 22 may include an array of red LEDs, an array of green LEDs, and an array of blue LEDs, and modulator 24 may directly modulate the red, green, and blue LEDs to form modulated light, thereby producing a specified image.

[0118] In a second configuration, modulator 24 may include a modulation panel, such as a liquid crystal panel. Light source 22 may produce uniform or nearly uniform illumination to illuminate the modulation panel. The modulation panel may include pixels. Each pixel may selectively attenuate a corresponding portion of the modulation panel area in response to an electrical modulation signal to form modulated light. In some examples, modulator 24 may include multiple modulation panels capable of modulating different colors of light. For example, modulator 24 may include a red modulation panel capable of attenuating red light from a red light source such as a red LED, a green modulation panel capable of attenuating green light from a green light source such as a green LED, and a blue modulation panel capable of attenuating blue light from a blue light source such as a blue LED.

[0119] In some examples of the second configuration, modulator 24 may receive uniform or nearly uniform white light from a white light source (e.g., a white light-emitting diode). The modulation panel may include a wavelength-selective filter on each pixel of the modulation panel. The panel pixels may be arranged in groups (such as three or four groups), where each group may form pixels of a color image. For example, each group may include panel pixels with a red filter, panel pixels with a green filter, and panel pixels with a blue filter. Other suitable configurations may also be used.

[0120] The visualization system 10 may include one or more modulation processors 26, which may receive video signals, for example, from one or more video generation processors 20, and in response, generate an electrically modulated signal. In a configuration where modulator 24 directly modulates light source 22, the electrically modulated signal may drive light source 24. In a configuration where modulator 24 includes a modulation panel, the electrically modulated signal may drive the modulation panel.

[0121] The visualization system 10 may include one or more beam combiners 28 (also called beam splitters 28) that can combine beams of different colors to form a single multicolor beam. For configurations where the light source 22 may include multiple light-emitting diodes of different colors, the visualization system 10 may include one or more wavelength-sensitive (e.g., dichroic) beam splitters 28 that can combine light of different colors to form a single multicolor beam.

[0122] The visualization system 10 can direct modulated light toward a viewer's eyes in at least one of two configurations. In a first configuration, the visualization system 10 can function as a projector and may include suitable projection optics 30 that can project the modulated light onto one or more screens 32. The screens 32 may be located at a suitable distance from the user's eyes. The visualization system 10 may optionally include one or more lenses 34 that can position the virtual image of the screens 32 at a suitable distance from the eyes, such as a near-focal distance, such as 500 mm, 750 mm, or another suitable distance. In some examples, the visualization system 10 may include a single screen 32 such that the modulated light can be directed toward both of the user's eyes. In some examples, the visualization system 10 may include two screens 32 such that the modulated light from each screen 32 can be directed toward the corresponding eye of the user. In some examples, the visualization system 10 may include more than two screens 32. In a second configuration, the visualization system 10 can direct the modulated light directly into one or both of the viewer's eyes. For example, the projection optics 30 can form an image on the retina of a user's eye, or on each retina of a user's two eyes. Example

[0123] Various embodiments are listed below. It should be understood that the embodiments listed below can be combined with all aspects of the invention and other embodiments.

[0124] Example (a). A light-emitting diode (LED) system includes: a display including a plurality of pixels, each of the pixels including a corresponding group of light-emitting diodes (LEDs), the plurality of pixels including: a first group of pixels configured to emit a first red dominant wavelength; a second group of pixels configured to emit a first green dominant wavelength; a third group of pixels configured to emit a first blue dominant wavelength; the first red dominant wavelength, the first green dominant wavelength, and the first blue dominant wavelength define an RGB (red-green-blue) color gamut; and a fourth group of pixels configured to emit non-white emission including luminous efficacy higher than that of either the first group of pixels or the third group of pixels, to increase the power efficiency of the device; and a controller configured to control the plurality of pixels individually and / or in groups.

[0125] Example (b). The LED system according to Example (a) wherein the fourth group of pixels is configured to emit a second red primary wavelength or a second blue primary wavelength.

[0126] Example (c). The LED system according to Example (a) or (b) wherein the fourth group of pixels is configured to emit a primary wavelength of 600±5 nm or 480±5 nm; and optionally: the first red primary wavelength is in the range of 610 to 630 nm; the first green primary wavelength is in the range of 530 to 555 nm; and the first blue primary wavelength is in the range of 465 to 470 nm.

[0127] Example (d). The LED system according to Example (a), wherein the fourth group of pixels is configured to emit a dominant wavelength of 575±5nm.

[0128] Example (e). The LED system according to any one of Examples (a) to (d) is configured to drive fewer than or equal to three groups of pixels during operation.

[0129] Example (f). The LED system according to any one of Examples (a) to (e) includes field-sequence driving configured to drive only two groups of pixels during operation.

[0130] Example (g). The LED system according to any one of Examples (a) to (f) further includes a thin-film display backplane, CMOS backplane, or CMOS microIC configured to drive each group of pixels.

[0131] Example (h). An LED system according to any one of Examples (a) to (g), wherein the LED comprises multicolor microLEDs, wherein at least a portion of the multicolor microLEDs comprises one or more tunnel junctions, such that a first group of microLEDs is configured to emit a first red dominant wavelength, a second group of microLEDs is configured to emit a first green dominant wavelength, a third group of microLEDs is configured to emit a first blue dominant wavelength, and a fourth group of microLEDs is configured to emit a non-white emission as a second red dominant wavelength or a second blue dominant wavelength.

[0132] Example (i). An LED system according to any one of Examples (a) to (g) includes one or more driver transistors configured as current sources for one or more pixel circuits.

[0133] Example (j). An LED system according to any one of Examples (a) to (i), wherein the multicolor microLEDs have a vertical arrangement, and the system is configured to short some of the tunnel junctions into short junctions during operation.

[0134] Example (k). The LED system according to Example (j) is configured to control the shorting junction using a reverse bias, and the shorting junction is effective as a photodetector.

[0135] Example (l). An LED system according to any one of Examples (a) to (g), wherein the LED comprises phosphor-converted microLEDs, each microLED having a blue emission region configured to emit a first blue dominant wavelength and three different downconverter materials on the blue emission region, the first downconverter material configured with the blue emission region for emitting a first green dominant wavelength, the second downconverter material configured with the blue emission region for emitting a first red dominant wavelength, and the third downconverter material configured with the blue emission region for emitting a second red dominant wavelength or a second blue dominant wavelength.

[0136] Example (m). A light-emitting diode (LED) array includes: a plurality of pixels, each of the pixels including a corresponding group of light-emitting diodes (LEDs), the plurality of pixels including: a first group of pixels configured to emit a first red dominant wavelength; a second group of pixels configured to emit a first green dominant wavelength; a third group of pixels configured to emit a first blue dominant wavelength; the first red dominant wavelength, the first green dominant wavelength, and the first blue dominant wavelength define an RGB (red-green-blue) color gamut; and a fourth group of pixels configured to emit non-white emission including luminous efficacy higher than that of either the first or third pixel, to increase the power efficiency of the device.

[0137] Example (n). According to the LED array of Example (m), the LEDs include multi-color micro-LEDs, wherein at least a portion of the multi-color micro-LEDs includes one or more tunnel junctions, such that a first group of micro-LEDs is configured to emit a first red dominant wavelength, a second group of micro-LEDs is configured to emit a first green dominant wavelength, a third group of micro-LEDs is configured to emit a first blue dominant wavelength, and a fourth group of micro-LEDs is configured to emit a non-white emission as a second red dominant wavelength or a second blue dominant wavelength.

[0138] Example (o). According to the LED array of Example (n), the micro-LEDs include a vertically stacked configuration of the micro-LEDs, comprising: a first epitaxial stack including: a first active region on a first n-type layer and a first p-type layer on the first active region; a second epitaxial stack including: a second active region on a second n-type layer and a second p-type layer on the second active region; a third epitaxial stack including: a third active region on a third n-type layer and a third p-type layer on the third active region; a fourth epitaxial stack including: a fourth active region on a fourth n-type layer and a fourth p-type layer on the fourth active region; and a first tunnel junction adjacent to the first epitaxial stack, a second tunnel junction adjacent to the second epitaxial stack, and a third tunnel junction adjacent to the third epitaxial stack; wherein the first, second, third, and fourth epitaxial stacks are vertically related within at least one set of pixels.

[0139] Example (p). According to the LED array of Example (o), wherein: a third epitaxial stack is above a second epitaxial stack; a second epitaxial stack is above a first epitaxial stack; a first tunnel junction separates the first and second epitaxial stacks; a fourth epitaxial stack is above the second epitaxial stack and below the third epitaxial stack, the second and fourth epitaxial stacks are separated by a second tunnel junction, and the fourth and third epitaxial stacks are separated by a third tunnel junction; and the fourth epitaxial stack is configured to emit a non-white emission with a wavelength greater than the first blue wavelength.

[0140] Example (q). According to the LED array of Example (o), wherein: a third epitaxial stack is above a second epitaxial stack; a second epitaxial stack is above a first epitaxial stack; a fourth epitaxial stack is above a first epitaxial stack and below a second epitaxial stack, the first and fourth epitaxial stacks are separated by a first tunnel junction, and the second and fourth epitaxial stacks are separated by a second tunnel junction; a third tunnel junction separates the second and third epitaxial stacks; and the fourth epitaxial stack is configured to emit non-white light with a wavelength less than a first red wavelength or greater than a first green wavelength.

[0141] Example (r). The LED array according to Example (m) includes a down-converter configuration, wherein the LEDs include: phosphor-converted microLEDs, each microLED having a blue emission region configured to emit a first blue dominant wavelength and three different down-converter materials on the blue emission region, the first down-converter material configured with the blue emission region for emitting a first green dominant wavelength, the second down-converter material configured with the blue emission region for emitting a first red dominant wavelength, and the third down-converter material configured with the blue emission region for emitting non-white emission as a second red dominant wavelength or a second blue dominant wavelength.

[0142] Example (s). An LED array according to any one of Examples (m) to (r), wherein the LEDs are integrated onto a monolithic substrate.

[0143] Example (t). An LED array according to any one of Examples (m) to (r), wherein the LED is a single LED attached to a device substrate.

[0144] Example (u). A method for operating a display, the method comprising: determining an image to be presented on the display; driving a plurality of pixels to provide the image, each of the pixels including a corresponding group of light-emitting diodes (LEDs), the plurality of pixels including: a first group of pixels configured to emit a first red dominant wavelength; a second group of pixels configured to emit a first green dominant wavelength; a third group of pixels configured to emit a first blue dominant wavelength; the first red dominant wavelength, the first green dominant wavelength, and the first blue dominant wavelength defining an RGB (red-green-blue) color gamut; and a fourth group of pixels configured to emit a non-white emission including a luminous efficacy higher than that of either the first or third pixel to increase the power efficiency of the device; and controlling individual pixels and / or groups of pixels of the plurality of pixels.

[0145] Example (v). According to the method described in Example (u), the fourth group of pixels is configured to emit a second red dominant wavelength or a second blue dominant wavelength.

[0146] Throughout this specification, references to "one embodiment," "some embodiments," "one or more embodiments," or simply "embodiment" mean that a particular feature, structure, material, or characteristic described in connection with an embodiment is included in at least one embodiment of this disclosure. Therefore, phrases such as "in one or more embodiments," "in some embodiments," "in one embodiment," or "in an embodiment" appearing throughout this specification do not necessarily refer to the same embodiment of this disclosure. Furthermore, specific features, structures, materials, or characteristics may be combined in one or more embodiments in any suitable manner.

[0147] Many modifications and other embodiments of the invention will arise for those skilled in the art from the teachings presented in the foregoing description and related drawings. Therefore, it should be understood that the invention is not limited to the specific embodiments disclosed, and that modifications and embodiments are intended to be included within the scope of the appended claims. It should also be understood that other embodiments of the invention may be practiced without elements / steps not specifically disclosed herein.

Claims

1. A light-emitting diode (LED) system, comprising: The display includes a plurality of pixels, each of which includes a corresponding group of light-emitting diodes (LEDs), the plurality of pixels including: The first group of pixels is configured to emit the first dominant red wavelength; The second group of pixels is configured to emit the first green main wavelength; The third group of pixels is configured to emit a first blue dominant wavelength; the first red dominant wavelength, the first green dominant wavelength, and the first blue dominant wavelength define the RGB (red-green-blue) color gamut; and A fourth group of pixels is configured to emit non-white emission, the non-white emission including a higher luminous efficacy than either the first group of pixels or the third group of pixels, to increase the power efficiency of the device; and A controller configured to control the plurality of pixels individually and / or in groups.

2. The LED system of claim 1, wherein the fourth group of pixels is configured to emit a second red primary wavelength or a second blue primary wavelength.

3. The LED system of claim 1, configured to drive fewer than or equal to three groups of pixels during operation.

4. The LED system of claim 1, further comprising a field-sequence drive configured to drive only two groups of pixels during operation.

5. The LED system of claim 1 further includes a thin-film display backplane, a CMOS backplane, or a CMOS microIC configured to drive each group of pixels.

6. The LED system of claim 1, wherein the LED comprises multicolor microLEDs, wherein at least a portion of the multicolor microLEDs comprises one or more tunnel junctions, such that a first group of microLEDs is configured to emit a first red dominant wavelength, a second group of microLEDs is configured to emit a first green dominant wavelength, a third group of microLEDs is configured to emit a first blue dominant wavelength, and a fourth group of microLEDs is configured to emit a non-white emission as a second red dominant wavelength or a second blue dominant wavelength.

7. The LED system of claim 1, comprising one or more driver transistors configured as current sources for one or more pixel circuits.

8. The LED system of claim 6, wherein the multicolor microLEDs are vertically arranged, and the system is configured to short some of the tunnel junctions into short junctions during operation.

9. The LED system of claim 8, configured to control the shorting junction using a reverse bias, wherein the shorting junction is effective as a photodetector.

10. The LED system of claim 1, wherein the LED comprises phosphor-converted microLEDs, each phosphor-converted microLED having a blue emission region configured to emit a first blue dominant wavelength and three different downconverter materials on the blue emission region, the first downconverter material configured with the blue emission region for emitting a first green dominant wavelength, the second downconverter material configured with the blue emission region for emitting a first red dominant wavelength, and the third downconverter material configured with the blue emission region for emitting a second red dominant wavelength or a second blue dominant wavelength.

11. A light-emitting diode (LED) array, comprising: A plurality of pixels, each of which includes a corresponding group of light-emitting diodes (LEDs), the plurality of pixels comprising: The first group of pixels is configured to emit the first dominant red wavelength; The second group of pixels is configured to emit the first green main wavelength; The third group of pixels is configured to emit a first blue dominant wavelength; the first red dominant wavelength, the first green dominant wavelength, and the first blue dominant wavelength define the RGB (red-green-blue) color gamut; and The fourth group of pixels is configured to emit non-white emission, which includes a higher luminous efficacy than either the first or third pixel, to increase the power efficiency of the device.

12. The LED array of claim 11, wherein the LEDs comprise multicolor microLEDs, wherein at least a portion of the multicolor microLEDs comprises one or more tunnel junctions, such that a first group of microLEDs is configured to emit a first red dominant wavelength, a second group of microLEDs is configured to emit a first green dominant wavelength, a third group of microLEDs is configured to emit a first blue dominant wavelength, and a fourth group of microLEDs is configured to emit a non-white emission as a second red dominant wavelength or a second blue dominant wavelength.

13. The LED array according to claim 12, The microLEDs include a vertically stacked configuration of microLEDs, wherein the vertically stacked configuration includes: The first epitaxial stack includes: a first active region on a first n-type layer, and a first p-type layer on the first active region; The second epitaxial stack includes: a second active region on the second n-type layer, and a second p-type layer on the second active region; The third epitaxial stack includes: a third active region on the third n-type layer, and a third p-type layer on the third active region; The fourth epitaxial stack includes: a fourth active region on a fourth n-type layer, and a fourth p-type layer on the fourth active region; and A first tunnel junction adjacent to the first epitaxial stack, a second tunnel junction adjacent to the second epitaxial stack, and a third tunnel junction adjacent to the third epitaxial stack. The first epitaxial stack, the second epitaxial stack, the third epitaxial stack, and the fourth epitaxial stack are vertically related within at least one set of pixels.

14. The LED array according to claim 13, wherein: The third epitaxial stack is placed on top of the second epitaxial stack; The second epitaxial stack is placed on top of the first epitaxial stack; The first tunnel junction separates the first epitaxial stack and the second epitaxial stack; The fourth epitaxial stack is above the second epitaxial stack and below the third epitaxial stack, the second epitaxial stack and the fourth epitaxial stack are separated by the second tunnel junction, and the fourth epitaxial stack and the third epitaxial stack are separated by the third tunnel junction; as well as The fourth epitaxial stack is configured to emit non-white light with a wavelength greater than the first blue wavelength.

15. The LED array according to claim 13, wherein: The third epitaxial stack is placed on top of the second epitaxial stack; The second epitaxial stack is placed on top of the first epitaxial stack; The fourth epitaxial stack is above the first epitaxial stack and below the second epitaxial stack, the first epitaxial stack and the fourth epitaxial stack are separated by the first tunnel junction, and the second epitaxial stack and the fourth epitaxial stack are separated by the second tunnel junction; The third tunnel junction separates the second epitaxial stack and the third epitaxial stack; as well as The fourth epitaxial stack is configured to emit non-white light with a wavelength less than the first red wavelength or greater than the first green wavelength.

16. The LED array of claim 11, comprising a down-converter configuration, wherein the LEDs comprise: The phosphor-converted microLED has a blue emission region configured to emit a first blue dominant wavelength and three different downconverter materials on the blue emission region. The first downconverter material configured with the blue emission region is used to emit a first green dominant wavelength, the second downconverter material configured with the blue emission region is used to emit a first red dominant wavelength, and the third downconverter material configured with the blue emission region is used to emit non-white emission as a second red dominant wavelength or a second blue dominant wavelength.

17. The LED array of claim 11, wherein the LEDs are integrated into a monolithic substrate.

18. The LED array of claim 11, wherein the LED is an individual LED attached to a device substrate.

19. A method for operating a display, the method comprising: Determine the image to be displayed on the monitor; A plurality of pixels are driven to provide the image, each of the pixels including a corresponding group of light-emitting diodes (LEDs), the plurality of pixels including: The first group of pixels is configured to emit the first dominant red wavelength; The second group of pixels is configured to emit the first green main wavelength; The third group of pixels is configured to emit a first blue dominant wavelength; the first red dominant wavelength, the first green dominant wavelength, and the first blue dominant wavelength define the RGB (red-green-blue) color gamut; and A fourth group of pixels is configured to emit non-white emission, the non-white emission including a higher luminous efficacy than either the first or third pixel, to increase the power efficiency of the device; and Control individual pixels of the plurality of pixels and / or groups of the plurality of pixels.

20. The method of claim 19, wherein the fourth group of pixels is configured to emit a second red dominant wavelength or a second blue dominant wavelength.

Images