Managing thermal resistance and planarity of display packages

Abstract

Disclosed herein are techniques for managing thermal resistance and planarity of display packages. According to certain embodiments, a device includes: a display package having a molding compound; a plurality of light emitting diode (LED) wafers arranged on a top surface of the display package, wherein each of the plurality of LED wafers includes a plurality of LEDs; a backplane wafer embedded in the molding compound of the display package, wherein the backplane wafer is electrically coupled to each of the plurality of LED wafers; and at least one spacer structure embedded in the molding compound of the display package. The backplane wafer and the at least one spacer structure together provide mechanical support and planar alignment for the plurality of LED wafers arranged on the top surface of the display package. The at least one spacer structure has a first thermal conductivity, and the molding compound has a second thermal conductivity lower than the first thermal conductivity.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority under 35 USC §119 to U.S. Provisional Patent Application No. 62 / 942,319, filed on December 2, 2019, the contents of which are hereby incorporated by reference in their entirety for all purposes.

[0003] background

[0004] Light emitting diodes (LEDs) convert electrical energy into light energy and offer many advantages over other light sources, such as reduced size, improved durability, and increased efficiency. LEDs can be used as light sources in many display systems (e.g., televisions, computer monitors, laptops, tablets, smartphones, projection systems, and wearable electronic devices). Micro-LEDs ("μLEDs") based on III-nitride semiconductors (e.g., alloys of AlN, GaN, InN, etc.) have begun to be developed for various display applications due to their small size (e.g., linear dimensions less than 100 μm, less than 50 μm, less than 10 μm, or less than 5 μm), high packing density (and therefore higher resolution), and high brightness. For example, micro-LEDs that emit light of different colors (e.g., red, green, and blue) can be used to form sub-pixels of a display system (e.g., a television or near-eye display system).

[0005] Overview

[0006] The present disclosure relates to managing thermal resistance and planarity of a display package. According to certain embodiments, a device includes: a display package having a molding compound; a plurality of light emitting diode (LED) wafers arranged on a top surface of the display package, wherein each of the plurality of LED wafers includes a plurality of LEDs; a backplane wafer embedded in the molding compound of the display package, wherein the backplane wafer is electrically coupled to each of the plurality of LED wafers; and at least one spacer structure embedded in the molding compound of the display package. The backplane wafer and the at least one spacer structure together provide mechanical support and planar alignment for the plurality of LED wafers arranged on the top surface of the display package. The at least one spacer structure has a first thermal conductivity, and the molding compound has a second thermal conductivity lower than the first thermal conductivity. The first thermal conductivity may be at least 50 W / m·K.

[0007] At least one spacer structure may include a slice having a slice height approximately equal to the height of the backplane wafer and a slice width greater than the slice height. The slice may be electrically connected to a redistribution layer (RDL) of a display package through at least one of a via or a bump. Alternatively, the slice may be electrically isolated from the RDL of the display package. The slice may include Si, Mo, AlN, Al2O3 and / or Cu.

[0008] Alternatively or additionally, at least one spacer structure may include a post having a post height approximately equal to the height of the backplane wafer and a post width less than the post height. The post may be electrically connected to a redistribution layer (RDL) of the display package through at least one of a via or a bump. Alternatively, the post may be electrically isolated from the RDL of the display package. The post may include Cu. The cross-section of the post may have a circular shape. Alternatively, the cross-section of the post may have a square shape with rounded corners.

[0009] At least one spacer structure may include a plurality of columns, wherein each of the plurality of columns has a column height approximately equal to the height of the backplane wafer and a column width less than the column height. The cross-section of each of the plurality of columns may have a circular shape, and the diameter of each of the plurality of columns may be at least half of the spacing of the plurality of columns. Alternatively, the cross-section of each of the plurality of columns may have a square shape with rounded corners, and the edge length of each of the plurality of columns may be at least half of the spacing of the plurality of columns. Alternatively or additionally, the cross-section of each of the plurality of columns may have a square shape with rounded corners, and the edge length of each of the plurality of columns may be at least three quarters of the spacing of the plurality of columns.

[0010] The cross section of each of the plurality of columns may have a circular shape, and the volume ratio of the plurality of columns to the molding compound may be at least 25%. Alternatively, the cross section of each of the plurality of columns may have a square shape with rounded corners, and the volume ratio of the plurality of columns to the molding compound may be at least 33%.

[0011] The display package may have a third thermal conductivity of at least 77 W / m·K. Alternatively or additionally, the display package may have a third thermal conductivity of at least 205 W / m·K.

[0012] The device may also include a circuit connected to the at least one spacer structure. The circuit may include an active Si structure, a capacitor, a resistor and / or an inductor.

[0013] This summary is not intended to identify the main features or essential features of the claimed subject matter, nor is it intended to be used alone to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate parts of the entire specification of the disclosure, any or all of the drawings, and each claim. The foregoing and other features and examples will be described in more detail below in the attached description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Illustrative embodiments are described in detail below with reference to the following drawings.

[0016] Figure 1 is a simplified block diagram of an example of an artificial reality system environment including a near-eye display in accordance with certain embodiments.

[0017] Figure 2 is a perspective view of an example of a near-eye display in the form of a head-mounted display (HMD) device for implementing some of the examples disclosed herein.

[0018] Figure 3 is a perspective view of an example of a near-eye display in the form of a pair of glasses for implementing some of the examples disclosed herein.

[0019] Figure 4 An example of an optical see-through augmented reality system including a waveguide display in accordance with some embodiments is shown.

[0020] Figure 5A An example of a near-eye display device including a waveguide display in accordance with some embodiments is shown.

[0021] Figure 5B An example of a near-eye display device including a waveguide display in accordance with some embodiments is shown.

[0022] Figure 6 An example of an image source assembly in an augmented reality system according to some embodiments is shown.

[0023] Fig. 7A An example of a light emitting diode (LED) having a vertical mesa structure is shown in accordance with some embodiments.

[0024] Figure 7B is a cross-sectional view of an example of an LED having a parabolic mesa structure according to some embodiments.

[0025] Fig. 8AAn example of a method for die-to-wafer bonding of an LED array according to some embodiments is shown.

[0026] Figure 8B An example of a method for wafer-to-wafer bonding of an LED array according to certain embodiments is shown.

[0027] Figure 9A-9D An example of a method for hybrid bonding of an LED array according to certain embodiments is shown.

[0028] Fig.10 An example of an LED array with secondary optics fabricated thereon is shown in accordance with certain embodiments.

[0029] Fig.11 An example of a display device including three LED arrays and spacer slices and / or spacer Cu pillars incorporated within a display package is shown.

[0030] Fig. 12A and Fig. 12B Examples of spacer posts that may be used to improve internal thermal resistance and planarity of a display package are shown.

[0031] Fig.13A and Fig. 13B Shown is a reference Fig.11 , Fig. 12A and Fig. 12B Examples of cross-sectional shapes of spacer posts are described.

[0032] Fig.14 is a simplified block diagram of an electronic system for an example of a near-eye display in accordance with certain embodiments.

[0033] The accompanying drawings depict embodiments of the present disclosure for purposes of illustration only. Those skilled in the art will readily recognize from the following description that alternative embodiments of the illustrated structures and methods may be employed without departing from the principles or benefits of the present disclosure.

[0034] In the accompanying drawings, similar components and / or features may have the same reference numeral. In addition, multiple components of the same type may be distinguished by following the reference numeral with a dash and a second reference numeral that distinguishes between the similar components. If only the first reference numeral is used in the specification, the description applies to any one of the similar components having the same first reference numeral, regardless of the second reference numeral.

[0035] Detailed Description

[0036] The present disclosure generally relates to light emitting diodes (LEDs). The LEDs described herein can be used in conjunction with various technologies, such as artificial reality systems. Artificial reality systems, such as head-mounted displays (HMDs) or heads-up display (HUD) systems, typically include displays configured to present artificial images depicting objects in a virtual environment. As in virtual reality (VR), augmented reality (AR), or mixed reality (MR) applications, the display can present virtual objects or combine images of real objects with virtual objects. For example, in an AR system, a user can view both a displayed image of a virtual object (e.g., a computer-generated image (CGI)) and the surrounding environment by, for example, viewing through transparent display glasses or lenses (commonly referred to as optical perspective) or viewing a displayed image of the surrounding environment captured by a camera (commonly referred to as video perspective). In some AR systems, an LED-based display subsystem can be used to present artificial images to a user.

[0037] As used herein, the term "light emitting diode (LED)" refers to a light source that includes at least an n-type semiconductor layer, a p-type semiconductor layer, and a light emitting region (i.e., an active region) between the n-type semiconductor layer and the p-type semiconductor layer. The light emitting region may include one or more semiconductor layers forming one or more heterostructures (e.g., quantum wells). In some embodiments, the light emitting region may include multiple semiconductor layers forming one or more multi-quantum wells (MQWs), each multi-quantum well including multiple (e.g., about 2 to 6) quantum wells.

[0038] As used herein, the term "micro-LED" or "μLED" refers to an LED having a chip wherein the linear dimension of the chip is less than about 200 μm, e.g., less than 100 μm, less than 50 μm, less than 20 μm, less than 10 μm, or less. For example, the linear dimension of a micro-LED may be as small as 6 μm, 5 μm, 4 μm, 2 μm, or less. Some micro-LEDs may have a linear dimension (e.g., length or diameter) comparable to a minority carrier diffusion length. However, the disclosure herein is not limited to micro-LEDs, but may also be applied to mini-LEDs and large LEDs.

[0039] As used herein, the term "bonding" may refer to various methods for physically connecting and / or electrically connecting two or more devices and / or wafers, such as adhesive bonding, metal-to-metal bonding, metal oxide bonding, wafer-to-wafer bonding, wafer-to-wafer bonding, hybrid bonding, welding, under-bump metallization, etc. For example, adhesive bonding can use a curable adhesive (e.g., epoxy resin) to physically bond two or more devices and / or wafers by bonding. Metal-to-metal bonding can include, for example, wire bonding or flip chip bonding using a welding interface (e.g., pad or ball), a conductive adhesive or a welding joint between metals. Metal oxide bonding can form metal and oxide patterns on each surface, bond the oxide portions together, and then bond the metal portions together to form a conductive path. Wafer-to-wafer bonding can bond two wafers (e.g., silicon wafers or other semiconductor wafers) without any intermediate layer and is based on chemical bonds between the surfaces of the two wafers. Wafer-to-wafer bonding may include wafer cleaning and other pre-processing, alignment and pre-bonding at room temperature, and annealing at elevated temperatures, such as about 250°C or higher. Wafer-to-wafer bonding may use bumps on one wafer to align features of a prefabricated chip with the drivers of the wafer. Hybrid bonding may include, for example, wafer cleaning, high-precision alignment of contacts of one wafer with contacts of another wafer, dielectric bonding of dielectric materials within the wafer at room temperature, and metal bonding of contacts annealed, for example, at 250°C-300°C or higher. As used herein, the term "bump" may broadly refer to metal interconnects used or formed during bonding.

[0040] In the following description, for the purpose of explanation, specific details are set forth in order to provide a thorough understanding of the examples of the present disclosure. However, it will be apparent that various examples can also be implemented without these specific details. For example, devices, systems, structures, components, methods and other components can be shown as components in block diagram form to avoid blurring the examples in unnecessary details. In other cases, well-known devices, processes, systems, structures and techniques can be shown without necessary details to avoid blurring the examples. The accompanying drawings and descriptions are not intended to be restrictive. The terms and expressions adopted in the present disclosure are used as descriptive terms rather than restrictive terms, and when using such terms and expressions, it is not intended to exclude any equivalents of the features shown and described or parts thereof. The word "example" is used herein to mean "used as an example, instance or explanation". Any embodiment or design described herein as an "example" is not necessarily interpreted as being more preferred or advantageous relative to other embodiments or designs.

[0041] Figure 1 is a simplified block diagram of an example of an artificial reality system environment 100 including a near-eye display 120 in accordance with some embodiments. Figure 1 The illustrated artificial reality system environment 100 may include a near-eye display 120, an optional external imaging device 150, and an optional input / output interface 140, each of which may be coupled to an optional console 110. Figure 1 An example of an artificial reality system environment 100 including one near-eye display 120, one external imaging device 150, and one input / output interface 140 is shown, but any number of these components may be included in the artificial reality system environment 100, or any of these components may be omitted. For example, there may be multiple near-eye displays 120 that are monitored by one or more external imaging devices 150 that communicate with the console 110. In some configurations, the artificial reality system environment 100 may not include the external imaging device 150, the optional input / output interface 140, and the optional console 110. In alternative configurations, different or additional components may be included in the artificial reality system environment 100.

[0042] The near-eye display 120 may be a head-mounted display that presents content to a user. Examples of content presented by the near-eye display 120 include one or more of the following: images, video, audio, or any combination thereof. In some embodiments, the audio may be presented via an external device (e.g., a speaker and / or headphones) that receives audio information from the near-eye display 120, the console 110, or both the near-eye display 120 and the console 110 and presents audio data based on the audio information. The near-eye display 120 may include one or more rigid bodies that may be rigidly or non-rigidly coupled to each other. Rigid coupling between rigid bodies may cause the coupled rigid bodies to act as a single rigid entity. Non-rigid coupling between rigid bodies may allow the rigid bodies to move relative to each other. In various embodiments, the near-eye display 120 may be implemented in any suitable form factor, including a pair of glasses. Referring below to Figure 2 and Figure 3 Some embodiments of the near-eye display 120 are further described. In addition, in various embodiments, the functionality described herein may be used in a head-mounted device (headset) that combines an image of an environment external to the near-eye display 120 with artificial reality content (e.g., computer-generated images). Thus, the near-eye display 120 may augment an image of a physical, real-world environment external to the near-eye display 120 with generated content (e.g., images, videos, sounds, etc.) to present an augmented reality to the user.

[0043] In various embodiments, the near eye display 120 may include one or more of the following: display electronics 122, display optics 124, and an eye tracking unit 130. In some embodiments, the near eye display 120 may also include one or more positioners 126, one or more position sensors 128, and an inertial measurement unit (IMU) 132. In various embodiments, the near eye display 120 may omit any of the following: eye tracking unit 130, positioners 126, position sensors 128, and IMU 132, or include additional elements. Furthermore, in some embodiments, the near eye display 120 may include a combination of Figure 1 The functions of the various components are described in detail.

[0044] The display electronics 122 may display an image to a user or facilitate the display of an image based on data received from, for example, the console 110. In various embodiments, the display electronics 122 may include one or more display panels, such as a liquid crystal display (LCD), an organic light emitting diode (OLED) display, an inorganic light emitting diode (ILED) display, a micro light emitting diode (μLED) display, an active matrix OLED display (AMOLED), a transparent OLED display (TOLED), or some other display. For example, in one implementation of the near-eye display 120, the display electronics 122 may include a front TOLED panel, a rear display panel, and optical components (e.g., an attenuator, a polarizer, or a diffractive or spectral film) between the front display panel and the rear display panel. The display electronics 122 may include pixels that emit light of a dominant color such as red, green, blue, white, or yellow. In some implementations, the display electronics 122 may display a three-dimensional (3D) image through a stereoscopic effect generated by a two-dimensional panel to create a subjective perception of image depth. For example, the display electronics 122 may include a left display and a right display located in front of the left eye and the right eye of the user, respectively. The left and right displays may present copies of an image that are horizontally offset relative to each other to create a stereoscopic effect (ie, the perception of depth in an image by a user viewing the image).

[0045] In certain embodiments, the display optics 124 may optically display image content or amplify image light received from the display electronics 122 (e.g., using optical waveguides and couplers), correct optical errors associated with the image light, and present the corrected image light to a user of the near-eye display 120. In various embodiments, the display optics 124 may include one or more optical elements, such as, for example, a substrate, an optical waveguide, an aperture, a Fresnel lens, a convex lens, a concave lens, an optical filter, an input / output coupler, or any other suitable optical element that may affect the image light emitted from the display electronics 122. The display optics 124 may include a combination of different optical elements and mechanical couplings to maintain the relative spacing and orientation of the optical elements in the combination. One or more of the optical elements in the display optics 124 may have an optical coating, such as an anti-reflective coating, a reflective coating, a filter coating, or a combination of different optical coatings.

[0046] The amplification of the image light by the display optics 124 can allow the display electronics 122 to be physically smaller, lighter, and consume less power than a larger display. Additionally, the amplification can increase the field of view of the displayed content. The amount of amplification of the image light by the display optics 124 can be changed by adjusting, adding optical elements, or removing optical elements from the display optics 124. In some embodiments, the display optics 124 can project the displayed image to one or more image planes that may be farther away from the user's eyes than the near eye display 120.

[0047] The display optics 124 may also be designed to correct one or more types of optical errors, such as two-dimensional optical errors, three-dimensional optical errors, or any combination thereof. Two-dimensional errors may include optical aberrations that occur in two dimensions. Example types of two-dimensional errors may include barrel distortion, pincushion distortion, longitudinal chromatic aberration, and lateral chromatic aberration. Three-dimensional errors may include optical errors that occur in three dimensions. Example types of three-dimensional errors may include spherical aberration, comatic aberration, field curvature, and astigmatism.

[0048] The locator 126 may be an object located at a specific location on the near eye display 120 relative to each other and relative to a reference point on the near eye display 120. In some implementations, the console 110 may identify the locator 126 in an image captured by the external imaging device 150 to determine the position, orientation, or both the position and orientation of the artificial reality head mounted device. The locator 126 may be an LED, a corner cube reflector, a reflective marker, a light source that contrasts with the environment in which the near eye display 120 operates, or any combination thereof. In embodiments where the locator 126 is an active component (e.g., an LED or other type of light emitting device), the locator 126 may emit light in the visible band (e.g., about 380 nm to 750 nm), light in the infrared (IR) band (e.g., about 750 nm to 1 mm), light in the ultraviolet band (e.g., about 10 nm to about 380 nm), light in another portion of the electromagnetic spectrum, or light in any combination of portions of the electromagnetic spectrum.

[0049] The external imaging device 150 may include one or more cameras, one or more video cameras, any other device capable of capturing an image including one or more locators 126, or any combination thereof. In addition, the external imaging device 150 may include one or more filters (e.g., to increase the signal-to-noise ratio). The external imaging device 150 may be configured to detect light emitted or reflected from the locators 126 in the field of view of the external imaging device 150. In embodiments where the locators 126 include passive elements (e.g., retroreflectors), the external imaging device 150 may include a light source that illuminates some or all of the locators 126, which may reflect light back into the external imaging device 150. Slow calibration data may be transmitted from the external imaging device 150 to the console 110, and the external imaging device 150 may receive one or more calibration parameters from the console 110 to adjust one or more imaging parameters (e.g., focal length, focus, frame rate, sensor temperature, shutter speed, aperture, etc.).

[0050] The position sensor 128 may generate one or more measurement signals in response to the movement of the near-eye display 120. Examples of the position sensor 128 may include an accelerometer, a gyroscope, a magnetometer, other motion detection or error correction sensors, or any combination thereof. For example, in some embodiments, the position sensor 128 may include multiple accelerometers for measuring translational motion (e.g., forward / backward, up / down, or left / right) and multiple gyroscopes for measuring rotational motion (e.g., pitch, yaw, or roll). In some embodiments, the various position sensors may be oriented orthogonally to each other.

[0051] The IMU 132 may be an electronic device that generates fast calibration data based on measurement signals received from one or more position sensors 128. The position sensors 128 may be located outside the IMU 132, inside the IMU 132, or any combination thereof. Based on one or more measurement signals from the one or more position sensors 128, the IMU 132 may generate fast calibration data that indicates an estimated position of the near eye display 120 relative to an initial position of the near eye display 120. For example, the IMU 132 may integrate the measurement signals received from the accelerometer over time to estimate a velocity vector, and integrate the velocity vector over time to determine an estimated position of a reference point on the near eye display 120. Alternatively, the IMU 132 may provide the sampled measurement signals to the console 110, which may determine the fast calibration data. Although the reference point may generally be defined as a point in space, in various embodiments, the reference point may also be defined as a point within the near eye display 120 (e.g., the center of the IMU 132).

[0052] The eye tracking unit 130 may include one or more eye tracking systems. Eye tracking may refer to determining the position of an eye relative to the near-eye display 120, including the orientation and positioning of the eye. The eye tracking system may include an imaging system that images one or more eyes, and may optionally include a light emitter that may generate light directed toward the eye so that light reflected by the eye can be captured by the imaging system. For example, the eye tracking unit 130 may include an incoherent or coherent light source (e.g., a laser diode) that emits light in the visible spectrum or infrared spectrum and a camera that captures light reflected by the user's eye. As another example, the eye tracking unit 130 may capture reflected radio waves emitted by a miniature radar unit. The eye tracking unit 130 may use low-power light emitters that emit light at a frequency and intensity that will not harm the eye or cause physical discomfort. The eye tracking unit 130 may be arranged to increase the contrast of the eye image captured by the eye tracking unit 130 while reducing the total power consumed by the eye tracking unit 130 (e.g., reducing the power consumed by the light emitter and imaging system included in the eye tracking unit 130). For example, in some implementations, eye tracking unit 130 may consume less than 100 milliwatts of power.

[0053] For example, the near-eye display 120 can use the orientation of the eyes to perform the following operations: determine the user's interpupillary distance (IPD), determine the gaze direction, introduce depth cues (e.g., blur images outside the user's primary line of sight), collect heuristics about user interactions in VR media (e.g., time spent on any particular subject, object, or frame based on the stimulus experienced), some other function based at least in part on the orientation of at least one user's eye, or any combination thereof. Because the orientation can be determined for both eyes of the user, the eye tracking unit 130 can determine where the user is looking. For example, determining the direction of the user's gaze may include determining a point of convergence based on the determined orientation of the user's left and right eyes. The convergence point can be the point where the two foveal axes of the user's eyes intersect. The direction of the user's gaze can be the direction of a line passing through the convergence point and the midpoint between the pupils of the user's eyes.

[0054] The input / output interface 140 may be a device that allows a user to send an action request to the console 110. The action request may be a request to perform a specific action. For example, the action request may be to start or end an application, or to perform a specific action within an application. The input / output interface 140 may include one or more input devices. Example input devices may include a keyboard, a mouse, a game controller, a glove, a button, a touch screen, or any other suitable device for receiving an action request and transmitting the received action request to the console 110. The action request received by the input / output interface 140 may be transmitted to the console 110, and the console 110 may perform an action corresponding to the requested action. In some embodiments, the input / output interface 140 may provide tactile feedback to the user according to the instructions received from the console 110. For example, when an action request is received, or when the console 110 has performed the requested action and transmitted the instruction to the input / output interface 140, the input / output interface 140 may provide tactile feedback. In some embodiments, the external imaging device 150 may be used to track the input / output interface 140, such as tracking the position or location of a controller (which may include, for example, an IR light source) or a user's hand to determine the user's movement. In some embodiments, the near-eye display 120 may include one or more imaging devices to track the input / output interface 140 , such as tracking the position or location of a controller or a user's hand to determine the user's movements.

[0055] The console 110 may provide content to the near-eye display 120 for presentation to the user based on information received from one or more of the external imaging device 150, the near-eye display 120, and the input / output interface 140. Figure 1In the example shown, the console 110 may include an application store 112, a head mounted device tracking module 114, an artificial reality engine 116, and an eye tracking module 118. Some embodiments of the console 110 may include a combination of Figure 1 The modules described may be different modules or additional modules. The functionality described further below may be distributed among the components of the console 110 in a manner different from that described here.

[0056] In some embodiments, console 110 may include a processor and a non-transitory computer-readable storage medium storing instructions executable by the processor. The processor may include multiple processing units that execute instructions in parallel. The non-transitory computer-readable storage medium may be any memory, such as a hard drive, a removable memory, or a solid-state drive (e.g., flash memory or dynamic random access memory (DRAM)). In various embodiments, in combination with Figure 1 The described modules of the console 110 may be encoded as instructions in a non-transitory computer-readable storage medium that, when executed by a processor, cause the processor to perform the functions described further below.

[0057] The application storage 112 may store one or more applications for execution by the console 110. An application may include a set of instructions that, when executed by a processor, generates content for presentation to a user. The content generated by the application may respond to input received from the user via movement of the user's eyes or from input / output interface 140. Examples of applications may include gaming applications, conferencing applications, video playback applications, or other suitable applications.

[0058] The head mounted device tracking module 114 may use the slow calibration information from the external imaging device 150 to track the movement of the near eye display 120. For example, the head mounted device tracking module 114 may use the observed localizers from the slow calibration information and the model of the near eye display 120 to determine the position of the reference point of the near eye display 120. The head mounted device tracking module 114 may also use the position information from the fast calibration information to determine the position of the reference point of the near eye display 120. Additionally, in some embodiments, the head mounted device tracking module 114 may use the fast calibration information, portions of the slow calibration information, or any combination thereof to predict the future position of the near eye display 120. The head mounted device tracking module 114 may provide the estimated or predicted future position of the near eye display 120 to the artificial reality engine 116.

[0059] The artificial reality engine 116 can execute an application within the artificial reality system environment 100 and receive position information of the near-eye display 120, acceleration information of the near-eye display 120, velocity information of the near-eye display 120, predicted future position of the near-eye display 120, or any combination thereof from the head mounted device tracking module 114. The artificial reality engine 116 can also receive estimated eye position and orientation information from the eye tracking module 118. Based on the received information, the artificial reality engine 116 can determine the content provided to the near-eye display 120 for presentation to the user. For example, if the received information indicates that the user has looked to the left, the artificial reality engine 116 can generate content for the near-eye display 120 that reflects (mirror) the movement of the user's eyes in the virtual environment. In addition, the artificial reality engine 116 can perform an action within an application executed on the console 110 in response to an action request received from the input / output interface 140, and provide feedback to the user indicating that the action has been performed. The feedback can be visual or auditory feedback via the near-eye display 120, or tactile feedback via the input / output interface 140.

[0060] The eye tracking module 118 may receive eye tracking data from the eye tracking unit 130 and determine the position of the user's eye based on the eye tracking data. The position of the eye may include the orientation, position, or both of the eye relative to the near-eye display 120 or any element thereof. Because the rotational axis of the eye changes depending on the positioning of the eye in its eye socket, determining the positioning of the eye in its eye socket may allow the eye tracking module 118 to more accurately determine the orientation of the eye.

[0061] Figure 2 2 is a perspective view of an example of a near-eye display in the form of an HMD device 200 for implementing some of the examples disclosed herein. The HMD device 200 may be, for example, part of a VR system, an AR system, an MR system, or any combination thereof. The HMD device 200 may include a body 220 and a headband 230. Figure 2 The bottom side 223, front side 225, and left side 227 of the body 220 are shown in perspective. The headband 230 can have an adjustable length or an extendable length. There can be enough space between the body 220 of the HMD device 200 and the headband 230 to allow the user to mount the HMD device 200 on the user's head. In various embodiments, the HMD device 200 can include additional components, fewer components, or different components. For example, in some embodiments, the HMD device 200 can include, for example, the following Figure 3 Eyeglass temples and temple tips are shown, rather than headband 230 .

[0062] The HMD device 200 can present media including virtual views and / or augmented views of a physical, real-world environment with computer-generated elements to a user. Examples of media presented by the HMD device 200 can include images (e.g., two-dimensional (2D) or three-dimensional (3D) images), video (e.g., 2D or 3D video), audio, or any combination thereof. The images and videos can be displayed via one or more display components (e.g., in the body 220 of the HMD device 200) that are enclosed in the HMD device 200. Figure 2 In various embodiments, one or more display components may include a single electronic display panel or multiple electronic display panels (e.g., one display panel for each eye of the user). For example, examples of electronic display panels may include an LCD, an OLED display, an ILED display, a μLED display, an AMOLED, a TOLED, some other display, or any combination thereof. The HMD device 200 may include two eye box areas.

[0063] In some implementations, the HMD device 200 may include various sensors (not shown), such as depth sensors, motion sensors, position sensors, and eye tracking sensors. Some of these sensors may use structured light patterns for sensing. In some implementations, the HMD device 200 may include an input / output interface for communicating with a console. In some implementations, the HMD device 200 may include a virtual reality engine (not shown), which may execute applications within the HMD device 200 and receive depth information, position information, acceleration information, velocity information, predicted future positions, or any combination thereof of the HMD device 200 from various sensors. In some implementations, the information received by the virtual reality engine may be used to generate signals (e.g., display instructions) to one or more display components. In some implementations, the HMD device 200 may include a locator (not shown, such as the locator 126), which is positioned in a fixed position on the body 220 relative to each other and relative to a reference point. Each locator may emit light that can be detected by an external imaging device.

[0064] Figure 3 is a perspective view of an example of a near-eye display 300 in the form of a pair of glasses for implementing some of the examples disclosed herein. The near-eye display 300 may be Figure 1 The near-eye display 300 may be a specific implementation of the near-eye display 120 and may be configured to operate as a virtual reality display, an augmented reality display, and / or a mixed reality display. The near-eye display 300 may include a frame 305 and a display 310. The display 310 may be configured to present content to a user. In some embodiments, the display 310 may include display electronics and / or display optics. For example, as described above with respect to Figure 1 As described with respect to the near-eye display 120 , the display 310 may include an LCD display panel, an LED display panel, or an optical display panel (eg, a waveguide display component).

[0065] The near-eye display 300 may also include various sensors 350a, 350b, 350c, 350d, and 350e on or within the frame 305. In some embodiments, the sensors 350a-350e may include one or more depth sensors, motion sensors, position sensors, inertial sensors, or ambient light sensors. In some embodiments, the sensors 350a-350e may include one or more image sensors configured to generate image data representing different fields of view in different directions. In some embodiments, the sensors 350a-350e may be used as input devices to control or affect the display content of the near-eye display 300, and / or provide an interactive VR / AR / MR experience to the user of the near-eye display 300. In some embodiments, the sensors 350a-350e may also be used for stereoscopic imaging.

[0066] In some embodiments, the near-eye display 300 may also include one or more illuminators 330 to project light into the physical environment. The projected light may be associated with different frequency bands (e.g., visible light, infrared light, ultraviolet light, etc.) and may serve a variety of purposes. For example, the illuminator 330 may project light in a dark environment (or in an environment with low intensity infrared light, ultraviolet light, etc.) to help the sensors 350a-350e capture images of different objects within the dark environment. In some embodiments, the illuminator 330 may be used to project a specific light pattern onto an object within the environment. In some embodiments, the illuminator 330 may be used as a locator, such as described above with reference to Figure 1 The locator 126 is described.

[0067] In some embodiments, the near-eye display 300 may also include a high-resolution camera 340. The camera 340 may capture images of the physical environment in the field of view. The captured images may be generated, for example, by a virtual reality engine (e.g., Figure 1 The virtual reality engine 116) is used to add virtual objects to the captured image or modify physical objects in the captured image, and the processed image can be displayed to the user by the display 310 for AR application or MR application.

[0068] Figure 4An example of an optical see-through augmented reality system 400 including a waveguide display according to some embodiments is shown. The augmented reality system 400 may include a projector 410 and a combiner 415. The projector 410 may include a light source or image source 412 and a projector optical device 414. In some embodiments, the light source or image source 412 may include one or more of the above-mentioned micro-LED devices. In some embodiments, the image source 412 may include a plurality of pixels displaying a virtual object, such as an LCD display panel or an LED display panel. In some embodiments, the image source 412 may include a light source that generates coherent light or partially coherent light. For example, the image source 412 may include a laser diode, a vertical cavity surface emitting laser, an LED, and / or the above-mentioned micro-LED. In some embodiments, the image source 412 may include a plurality of light sources (e.g., an array of the above-mentioned micro-LEDs), each of which emits a monochromatic image light corresponding to a primary color (e.g., red, green, or blue). In some embodiments, the image source 412 may include three two-dimensional micro-LED arrays, wherein each two-dimensional micro-LED array may include a micro-LED configured to emit a primary color (e.g., red, green, or blue) light. In some embodiments, the image source 412 may include an optical pattern generator, such as a spatial light modulator. The projector optics 414 may include one or more optical components that may condition the light from the image source 412, such as expanding, collimating, scanning, or projecting the light from the image source 412 to the combiner 415. For example, the one or more optical components may include one or more lenses, liquid lenses, mirrors, apertures, and / or gratings. For example, in some embodiments, the image source 412 may include one or more one-dimensional micro-LED arrays or elongated two-dimensional micro-LED arrays, and the projector optics 414 may include one or more one-dimensional scanners (e.g., micro-mirrors or prisms) configured to scan the one-dimensional micro-LED array or the elongated two-dimensional micro-LED array to generate an image frame. In some embodiments, the projector optics 414 may include a liquid lens (e.g., a liquid crystal lens) having a plurality of electrodes that allows the light from the image source 412 to be scanned.

[0069] The combiner 415 may include an input coupler 430 for coupling light from the projector 410 into the substrate 420 of the combiner 415. The combiner 415 may transmit at least 50% of the light in a first wavelength range and reflect at least 25% of the light in a second wavelength range. For example, the first wavelength range may be visible light from about 400 nm to about 650 nm, and the second wavelength range may be in the infrared band, for example, from about 800 nm to about 1000 nm. The input coupler 430 may include a volume holographic grating, a diffractive optical element (DOE) (e.g., a surface relief grating), an inclined surface of the substrate 420, or a refractive coupler (e.g., a wedge or a prism). For example, the input coupler 430 may include a reflective volume Bragg grating or a transmissive volume Bragg grating. The input coupler 430 may have a coupling efficiency greater than 30%, 50%, 75%, 90%, or more for visible light. The light coupled into the substrate 420 may propagate within the substrate 420 by, for example, total internal reflection (TIR). Substrate 420 may be in the form of a lens for a pair of glasses. Substrate 420 may have a flat or curved surface and may include one or more types of dielectric materials, such as glass, quartz, plastic, polymer, poly(methyl methacrylate) (PMMA), crystal, or ceramic. The thickness of the substrate may range, for example, from less than about 1 mm to about 10 mm or more. Substrate 420 may be transparent to visible light.

[0070] The substrate 420 may include or may be coupled to a plurality of output couplers 440, each of which is configured to extract at least a portion of the light guided by and propagating within the substrate 420 from the substrate 420 and to guide the extracted light 460 to a viewing window 495, where an eye 490 of a user of the augmented reality system 400 may be located when the augmented reality system 400 is used. The plurality of output couplers 440 may replicate an exit pupil to increase the size of the viewing window 495 so that the displayed image is visible in a larger area. As with the input coupler 430, the output coupler 440 may include a grating coupler (e.g., a volume holographic grating or a surface relief grating), other diffractive optical elements (DOEs), prisms, and the like. For example, the output coupler 440 may include a reflective volume Bragg grating or a transmissive volume Bragg grating. The output coupler 440 may have different coupling (e.g., diffraction) efficiencies at different locations. The substrate 420 may also allow light 450 from the environment in front of the combiner 415 to pass through with little or no loss. The output coupler 440 may also allow light 450 to pass through with little loss. For example, in some implementations, the output coupler 440 may have a very low diffraction efficiency for the light 450, so that the light 450 may be refracted or otherwise pass through the output coupler 440 with little loss, and thus may have a higher intensity than the extracted light 460. In some implementations, the output coupler 440 may have a high diffraction efficiency for the light 450, and may diffract the light 450 in certain desired directions (i.e., diffraction angles) with little loss. Thus, the user can view a combined image of the environment in front of the combiner 415 and the image of the virtual object projected by the projector 410.

[0071] Figure 5AAn example of a near-eye display (NED) device 500 including a waveguide display 530 according to some embodiments is shown. The NED device 500 may be an example of a near-eye display 120, an augmented reality system 400, or another type of display device. The NED device 500 may include a light source 510, a projection optical device 520, and a waveguide display 530. The light source 510 may include a plurality of light emitter panels for different colors, such as a red light emitter 512 panel, a green light emitter 514 panel, and a blue light emitter 516 panel. The red light emitters 512 are organized into an array; the green light emitters 514 are organized into an array; and the blue light emitters 516 are organized into an array. The size and spacing of the light emitters in the light source 510 may be small. For example, each light emitter may have a diameter of less than 2 μm (e.g., about 1.2 μm) and the spacing may be less than 2 μm (e.g., about 1.5 μm). Thus, the number of light emitters in each of the red light emitters 512, the green light emitters 514, and the blue light emitters 516 may be equal to or greater than the number of pixels in a display image, such as 960×720, 1280×720, 1440×1080, 1920×1080, 2160×1080, or 2560×1080 pixels. Thus, a display image may be generated simultaneously by the light source 510. A scanning element may not be used in the NED device 500.

[0072] Before reaching the waveguide display 530, the light emitted by the light source 510 can be conditioned by the projection optical device 520, which can include a lens array. The projection optical device 520 can collimate or focus the light emitted by the light source 510 to the waveguide display 530, and the waveguide display 530 can include a coupler 532 for coupling the light emitted by the light source 510 into the waveguide display 530. The light coupled into the waveguide display 530 can be, for example, Figure 4 The total internal reflection propagates within the waveguide display 530. The coupler 532 may also couple a portion of the light propagating within the waveguide display 530 out of the waveguide display 530 and toward the eye 590 of the user.

[0073] Figure 5BAn example of a near-eye display (NED) device 550 including a waveguide display 580 according to some embodiments is shown. In some embodiments, the NED device 550 can use a scanning mirror 570 to project light from a light source 540 to an image field where a user's eye 590 may be located. The NED device 550 can be an example of a near-eye display 120, an augmented reality system 400, or another type of display device. The light source 540 can include one or more rows or one or more columns of light emitters of different colors, such as multiple rows of red light emitters 542, multiple rows of green light emitters 544, and multiple rows of blue light emitters 546. For example, the red light emitters 542, the green light emitters 544, and the blue light emitters 546 can each include N rows, each row including, for example, 2560 light emitters (pixels). The red light emitters 542 are organized into an array; the green light emitters 544 are organized into an array; and the blue light emitters 546 are organized into an array. In some embodiments, the light source 540 can include a single row of light emitters for each color. In some embodiments, light source 540 may include multiple columns of light emitters for each of the colors red, green, and blue, where each column may include, for example, 1080 light emitters. In some embodiments, the size and / or spacing of the light emitters in light source 540 may be relatively large (e.g., about 3 μm-about 5 μm), and thus light source 540 may not include enough light emitters to simultaneously generate a complete display image. For example, the number of light emitters for a single color may be less than the number of pixels in the display image (e.g., 2560×1080 pixels). The light emitted by light source 540 may be a set of collimated or divergent light beams.

[0074] Before reaching the scanning mirror 570, the light emitted by the light source 540 can be conditioned by various optical devices, such as a collimating lens or a freeform optical element 560. The freeform optical element 560 may include, for example, a multi-faceted prism or another light folding element, which can direct the light emitted by the light source 540 to the scanning mirror 570, such as changing the propagation direction of the light emitted by the light source 540, for example, by about 90° or more. In some embodiments, the freeform optical element 560 may be rotatable to scan the light. The scanning mirror 570 and / or the freeform optical element 560 can reflect and project the light emitted by the light source 540 to the waveguide display 580, which may include a coupler 582 for coupling the light emitted by the light source 540 into the waveguide display 580. The light coupled into the waveguide display 580 can be transmitted by, for example, the above reference. Figure 4The total internal reflection propagates within the waveguide display 580. The coupler 582 may also couple a portion of the light propagating within the waveguide display 580 out of the waveguide display 580 and toward the eye 590 of the user.

[0075] The scanning mirror 570 may include a micro-electromechanical system (MEMS) mirror or any other suitable mirror. The scanning mirror 570 may rotate to scan in one dimension or two dimensions. As the scanning mirror 570 rotates, the light emitted by the light source 540 may be directed to different areas of the waveguide display 580, so that in each scanning cycle, a complete display image may be projected onto the waveguide display 580 and directed by the waveguide display 580 to the user's eye 590. For example, in an embodiment where the light source 540 includes light emitters for all pixels in one or more rows or one or more columns, the scanning mirror 570 may rotate in a column or row direction (e.g., an x ​​or y direction) to scan the image. In an embodiment where the light source 540 includes light emitters for some pixels but not all pixels in one or more rows or one or more columns, the scanning mirror 570 may rotate in both row and column directions (e.g., both x and y directions) to project the display image (e.g., using a raster-type scanning pattern).

[0076] The NED device 550 can operate in a predefined display cycle. A display cycle (e.g., a display cycle) can refer to the duration in which a complete image is scanned or projected. For example, the display cycle can be the inverse of the desired frame rate. In the NED device 550 including the scanning mirror 570, the display cycle can also be referred to as a scanning cycle or a scanning cycle. The light generated by the light source 540 can be synchronized with the rotation of the scanning mirror 570. For example, each scanning cycle can include multiple scanning steps, wherein the light source 540 can generate a different light pattern in each corresponding scanning step.

[0077] In each scanning cycle, as the scanning mirror 570 rotates, a display image can be projected onto the waveguide display 580 and the user's eye 590. The actual color value and light intensity (e.g., brightness) of a given pixel position of the display image can be the average of the light beams of three colors (e.g., red, green, and blue) that illuminate the pixel position during the scanning cycle. After completing a scanning cycle, the scanning mirror 570 can return to the initial position to project light for the first few rows of the next display image, or can rotate in the opposite direction or scan the pattern to project light for the next display image, where a new set of drive signals can be fed to the light source 540. The same process can be repeated as the scanning mirror 570 rotates in each scanning cycle. Therefore, different images can be projected to the user's eye 590 in different scanning cycles.

[0078] Figure 6 An example of an image source component 610 in a near-eye display system 600 according to some embodiments is shown. For example, the image source component 610 may include: a display panel 640, which may generate a display image to be projected to the user's eyes; and a projector 650, which may project the display image generated by the display panel 640 to the user's eyes as described above. Figure 4-5B The display panel 640 may include a light source 642 and a driver circuit 644 for the light source 642. For example, the light source 642 may include the light source 510 or 540. For example, the projector 650 may include the free-form optical element 560, the scanning mirror 570, and / or the projection optical device 520 described above. The near-eye display system 600 may also include a controller 620 that synchronously controls the light source 642 and the projector 650 (e.g., the scanning mirror 570). The image source component 610 may generate image light and output the image light to the waveguide display ( Figure 6 5 (not shown), such as waveguide display 530 or 580. As described above, the waveguide display can receive image light at one or more input coupling elements and direct the received image light to one or more output coupling elements. The input and output coupling elements can include, for example, diffraction gratings, holographic gratings, prisms, or any combination thereof. The input coupling elements can be selected to cause total internal reflection of the waveguide display. The output coupling elements can couple a portion of the total internally reflected image light out of the waveguide display.

[0079] As described above, the light source 642 may include a plurality of light emitters arranged in an array or matrix. Each light emitter may emit monochromatic light, such as red light, blue light, green light, infrared light, etc. Although RGB colors are often discussed in the present disclosure, the embodiments described herein are not limited to using red, green, and blue as primary colors. Other colors may also be used as primary colors of the near-eye display system 600. In some embodiments, the display panel according to the embodiment may use more than three primary colors. Each pixel in the light source 642 may include three sub-pixels, including a red micro-LED, a green micro-LED, and a blue micro-LED. Semiconductor LEDs generally include an active light-emitting layer within a multilayer semiconductor material. The multilayer semiconductor material may include different composite materials or the same basic material with different dopants and / or different doping densities. For example, the multilayer semiconductor material may include an n-type material layer, an active region that may include a heterostructure (e.g., one or more quantum wells), and a p-type material layer. The multilayer semiconductor material may be grown on a surface of a substrate having a certain orientation. In some embodiments, in order to improve light extraction efficiency, a mesa including at least some semiconductor material layers may be formed.

[0080] Controller 620 can control image rendering operations of image source component 610, such as operation of light source 642 and / or projector 650. For example, controller 620 can determine instructions for image source component 610 to render one or more display images. The instructions can include display instructions and scanning instructions. In some embodiments, the display instructions can include an image file (e.g., a bitmap file). For example, the display instructions can be sent from a console (e.g., as described above). Figure 1 The controller 620 may include a combination of hardware, software, and / or firmware not shown here to avoid obscuring other aspects of the present disclosure.

[0081] In some embodiments, the controller 620 may be a graphics processing unit (GPU) of the display device. In other embodiments, the controller 620 may be another type of processor. The operations performed by the controller 620 may include acquiring content for display and dividing the content into discrete portions. The controller 620 may provide a scanning instruction to the light source 642, the scanning instruction including an address corresponding to a separate source element of the light source 642 and / or an electrical bias applied to the separate source element. The controller 620 may instruct the light source 642 to sequentially present the discrete portions using light emitters corresponding to one or more rows of pixels in an image ultimately displayed to the user. The controller 620 may also instruct the projector 650 to perform different adjustments to the light. For example, the controller 620 may control the projector 650 to scan the discrete portions to the image as described above with reference to FIG. Figure 5B The present invention relates to a waveguide display (e.g., waveguide display 580) that is coupled to different regions of the element. Therefore, each discrete portion is presented at a different corresponding position at the exit pupil of the waveguide display. Although each discrete portion is presented at a different corresponding time, the presentation and scanning of the discrete portions occurs quickly enough so that the user's eyes can integrate the different portions into a single image or a series of images.

[0082] Image processor 630 may be a general purpose processor and / or one or more dedicated circuits dedicated to performing the features described herein. In one embodiment, a general purpose processor may be coupled to a memory to execute software instructions that cause the processor to perform the specific processes described herein. In another embodiment, image processor 630 may be one or more circuits dedicated to performing specific features. Although Figure 6The image processor 630 in FIG. 6 is shown as an independent unit separate from the controller 620 and the driver circuit 644, but in other embodiments, the image processor 630 may be a subunit of the controller 620 or the driver circuit 644. In other words, in these embodiments, the controller 620 or the driver circuit 644 may perform various image processing functions of the image processor 630. The image processor 630 may also be referred to as an image processing circuit.

[0083] exist Figure 6 In the example shown, the light source 642 can be driven by a driver circuit 644 based on data or instructions (e.g., display and scan instructions) sent from the controller 620 or the image processor 630. In one embodiment, the driver circuit 644 may include a circuit board connected to the individual light emitters of the light source 642 and mechanically holding the individual light emitters of the light source 642. The light source 642 can emit light according to one or more illumination parameters set by the controller 620 and potentially adjusted by the image processor 630 and the driver circuit 644. The light source 642 can generate light using the illumination parameters. For example, the illumination parameters may include source wavelength, pulse rate, pulse amplitude, beam type (continuous or pulsed), one or more other parameters that may affect the emitted light, or any combination thereof. In some embodiments, the source light generated by the light source 642 may include multiple beams of red light, green light, and blue light, or any combination thereof.

[0084] Projector 650 may perform a set of optical functions, such as focusing, combining, adjusting, or scanning image light generated by light source 642. In some embodiments, projector 650 may include a combining assembly, a light adjustment assembly, or a scanning mirror assembly. Projector 650 may include one or more optical components that optically adjust and potentially redirect light from light source 642. An example of adjusting light may include adjusting light, such as expanding, collimating, correcting one or more optical errors (e.g., field curvature, chromatic aberration, etc.), some other adjustment of light, or any combination thereof. For example, the optical components of projector 650 may include lenses, mirrors, apertures, gratings, or any combination thereof.

[0085] The projector 650 can redirect the image light via one or more reflective and / or refractive parts thereof so that the image light is projected toward the waveguide display in a specific orientation. The position at which the image light is redirected toward the waveguide display can depend on the specific orientation of the one or more reflective and / or refractive parts. In some embodiments, the projector 650 includes a single scanning mirror that scans in at least two dimensions. In other embodiments, the projector 650 may include multiple scanning mirrors, each scanning mirror scanning in directions orthogonal to each other. The projector 650 may perform (horizontal or vertical) raster scanning, double resonance scanning, or any combination thereof. In some embodiments, the projector 650 may perform controlled vibrations in the horizontal and / or vertical directions at a specific oscillation frequency to scan in two dimensions and generate a two-dimensional projection image of the media presented to the user's eyes. In other embodiments, the projector 650 may include a lens or prism that can be used for similar or identical functions to one or more scanning mirrors. In some embodiments, the image source component 610 may not include a projector, wherein the light emitted by the light source 642 may be directly incident on the waveguide display.

[0086] In semiconductor LEDs, photons are typically generated by recombination of electrons and holes within the active region (e.g., one or more semiconductor layers) with a certain internal quantum efficiency, where the internal quantum efficiency is the proportion of radiative electron-hole recombination in the active region that emits a photon. The generated light can then be extracted from the LED in a specific direction or within a specific solid angle. The ratio of the number of emitted photons extracted from the LED to the number of electrons that passed through the LED is called the external quantum efficiency, which describes how efficiently the LED converts injected electrons into photons extracted from the device.

[0087] The external quantum efficiency may be proportional to the injection efficiency, the internal quantum efficiency, and the extraction efficiency. The injection efficiency refers to the fraction of electrons that are injected through the device into the active region. The extraction efficiency is the fraction of photons generated in the active region that escape from the device. For LEDs, and in particular micro-LEDs with reduced physical size, it may be challenging to improve the internal quantum efficiency and the external quantum efficiency and / or control the emission spectrum. In some embodiments, to improve the light extraction efficiency, a mesa may be formed that includes at least some layers of semiconductor material.

[0088] Fig. 7AAn example of an LED 700 having a vertical table structure is shown. LED 700 can be a light emitter in light source 510, 540 or 642. LED 700 can be a micro LED made of an inorganic material (e.g., a multilayer semiconductor material). A layered semiconductor light emitting device may include a multilayer III-V semiconductor material. The III-V semiconductor material may include one or more III-group elements (e.g., aluminum (Al), gallium (Ga), or indium (In)) in combination with a V-group element (e.g., nitrogen (N), phosphorus (P), arsenic (As), or antimony (Sb)). When the V-group element of the III-V semiconductor material includes nitrogen, the III-V semiconductor material is referred to as a III-group nitride material. A layered semiconductor light emitting device may be manufactured by growing multiple epitaxial layers on a substrate using techniques such as vapor phase epitaxy (VPE), liquid phase epitaxy (LPE), molecular beam epitaxy (MBE), or metal organic chemical vapor deposition (MOCVD). For example, layers of semiconductor material can be grown layer by layer on a substrate having a certain lattice orientation (e.g., a polar orientation, a non-polar orientation, or a semi-polar orientation), such as a GaN substrate, a GaAs substrate, or a GaP substrate, or substrates including but not limited to: sapphire, silicon carbide, silicon, zinc oxide, boron nitride, lithium aluminate, lithium niobate, germanium, aluminum nitride, lithium gallate, partially substituted spinel, or a quaternary tetragonal oxide sharing a β-LiAlO2 structure, wherein the substrate can be cut in a specific direction to expose a specific plane as a growth surface.

[0089] exist Fig. 7AIn the example shown, the LED 700 may include a substrate 710, which may include, for example, a sapphire substrate or a GaN substrate. A semiconductor layer 720 may be grown on the substrate 710. The semiconductor layer 720 may include a III-V material (e.g., GaN) and may be p-type doped (e.g., doped with Mg, Ca, Zn, or Be) or n-type doped (e.g., doped with Si or Ge). One or more active layers 730 may be grown on the semiconductor layer 720 to form an active region. The active layer 730 may include a III-V material (e.g., one or more InGaN layers, one or more AlInGaP layers, and / or one or more GaN layers), which may form one or more heterostructures, such as one or more quantum wells or MQWs. A semiconductor layer 740 may be grown on the active layer 730. The semiconductor layer 740 may include a III-V material (e.g., GaN) and may be p-type doped (e.g., doped with Mg, Ca, Zn, or Be) or n-type doped (e.g., doped with Si or Ge). One of the semiconductor layer 720 and the semiconductor layer 740 may be a p-type layer and the other may be an n-type layer. The semiconductor layer 720 and the semiconductor layer 740 sandwich the active layer 730 to form a light emitting region. For example, the LED 700 may include an InGaN layer between a p-type GaN layer doped with magnesium and an n-type GaN layer doped with silicon or oxygen. In some embodiments, the LED 700 may include an AlInGaP layer between a p-type AlInGaP layer doped with zinc or magnesium and an n-type AlInGaP layer doped with selenium, silicon, or tellurium.

[0090] In some embodiments, an electron blocking layer (EBL) may be grown ( Fig. 7A (not shown) to form a layer between at least one of the semiconductor layer 720 or the semiconductor layer 740 and the active layer 730. The EBL can reduce electron leakage current and improve the efficiency of the LED. In some embodiments, the heavily doped semiconductor layer 750 (e.g., P + or P ++ A semiconductor layer 740 may be formed on the semiconductor layer 740 and serve as a contact layer for forming an ohmic contact and reducing the contact resistance of the device. In some embodiments, a conductive layer 760 may be formed on the heavily doped semiconductor layer 750. The conductive layer 760 may include, for example, indium tin oxide (ITO) or an Al / Ni / Au film. In one example, the conductive layer 760 may include a transparent ITO layer.

[0091] In order to contact the semiconductor layer 720 (e.g., n-GaN layer) and more efficiently extract the light emitted by the active layer 730 from the LED 700, the semiconductor material layer (including the heavily doped semiconductor layer 750, the semiconductor layer 740, the active layer 730, and the semiconductor layer 720) can be etched to expose the semiconductor layer 720 and form a mesa structure including layers 720-760. The mesa structure can confine carriers within the device. Etching the mesa structure can result in the formation of a mesa sidewall 732 that can be orthogonal to the growth plane. A passivation layer 770 can be formed on the sidewall 732 of the mesa structure. The passivation layer 770 can include an oxide layer, such as a SiO2 layer, and can act as a reflector to reflect the emitted light from the LED 700. The contact layer 780 can include a metal layer (e.g., Al, Au, Ni, Ti, or any combination thereof), which can be formed on the semiconductor layer 720 and can act as an electrode of the LED 700. Furthermore, another contact layer 790 , such as an Al / Ni / Au metal layer, may be formed on the conductive layer 760 and may serve as another electrode of the LED 700 .

[0092] When a voltage signal is applied to the contact layers 780 and 790, electrons and holes can recombine in the active layer 730, where the recombination of the electrons and holes can cause photon emission. The wavelength and energy of the emitted photons can depend on the energy band gap between the valence band and the conduction band in the active layer 730. For example, an InGaN active layer can emit green or blue light, an AlGaN active layer can emit blue to ultraviolet light, and an AlInGaP active layer can emit red, orange, yellow, or green light. The emitted photons can be reflected by the passivation layer 770 and can leave the LED 700 from the top (e.g., the conductive layer 760 and the contact layer 790) or the bottom (e.g., the substrate 710).

[0093] In some embodiments, the LED 700 may include one or more other components (e.g., a lens) on the light emitting surface (e.g., substrate 710) to focus or collimate the emitted light or couple the emitted light into a waveguide. In some embodiments, the LED may include a table of another shape (e.g., a planar, conical, semi-parabolic, or parabolic shape), and the base area of ​​the table may be circular, rectangular, hexagonal, or triangular. For example, the LED may include a table of a curved shape (e.g., a parabolic shape) and / or a non-curved shape (e.g., a conical shape). The table may be truncated or not truncated.

[0094] Figure 7B705 is a cross-sectional view of an example of an LED 705 having a parabolic mesa structure. Similar to LED 700, LED 705 may include multiple layers of semiconductor materials, such as multiple layers of III-V semiconductor materials. The semiconductor material layers may be epitaxially grown on a substrate 715 (e.g., a GaN substrate or a sapphire substrate). For example, a semiconductor layer 725 may be grown on substrate 715. The semiconductor layer 725 may include a III-V material (e.g., GaN) and may be p-type doped (e.g., doped with Mg, Ca, Zn, or Be) or n-type doped (e.g., doped with Si or Ge). One or more active layers 735 may be grown on the semiconductor layer 725. The active layer 735 may include a III-V material (such as one or more InGaN layers, one or more AlInGaP layers, and / or one or more GaN layers), which may form one or more heterostructures, such as one or more quantum wells. A semiconductor layer 745 may be grown on the active layer 735. The semiconductor layer 745 may include a III-V material such as GaN and may be p-type doped (e.g., doped with Mg, Ca, Zn, or Be) or n-type doped (e.g., doped with Si or Ge). One of the semiconductor layer 725 and the semiconductor layer 745 may be a p-type layer and the other may be an n-type layer.

[0095] In order to make contact with the semiconductor layer 725 (e.g., an n-type GaN layer) and more efficiently extract light emitted by the active layer 735 from the LED 705, the semiconductor layer can be etched to expose the semiconductor layer 725 and form a mesa structure including layers 725-745. The mesa structure can confine carriers within the injection region of the device. Etching the mesa structure can result in the formation of mesa sidewalls (also referred to herein as facets), which may be non-parallel to or in some cases orthogonal to the growth plane associated with the crystal growth of the layers 725-745.

[0096] like Figure 7B As shown, LED 705 can have a table structure including a flat top. A dielectric layer 775 (e.g., SiO2 or SiNx) can be formed on the facets of the table structure. In some embodiments, the dielectric layer 775 can include a multilayer dielectric material. In some embodiments, a metal layer 795 can be formed on the dielectric layer 775. The metal layer 795 can include one or more metal or metal alloy materials, such as aluminum (Al), silver (Ag), gold (Au), platinum (Pt), titanium (Ti), copper (Cu) or any combination thereof. The dielectric layer 775 and the metal layer 795 can form a table reflector that can reflect the light emitted by the active layer 735 toward the substrate 715. In some embodiments, the table reflector can be parabolic in shape to act as a parabolic reflector that can at least partially collimate the emitted light.

[0097] Electrical contacts 765 and 785 may be formed on semiconductor layer 745 and semiconductor layer 725, respectively, to act as electrodes. Electrical contacts 765 and 785 may each include a conductive material such as Al, Au, Pt, Ag, Ni, Ti, Cu, or any combination thereof (e.g., Ag / Pt / Au or Al / Ni / Au), and may act as electrodes of LED 705. Figure 7B In the example shown, the electrical contact 785 can be an n-type contact, and the electrical contact 765 can be a p-type contact. The electrical contact 765 and the semiconductor layer 745 (e.g., a p-type semiconductor layer) can form a back reflector for reflecting light emitted by the active layer 735 back toward the substrate 715. In some embodiments, the electrical contact 765 and the metal layer 795 include (one or more) the same material and can be formed using the same process. In some embodiments, an additional conductive layer (not shown) can be included as an intermediate conductive layer between the electrical contacts 765 and 785 and the semiconductor layer.

[0098] When a voltage signal is applied across contacts 765 and 785, electrons and holes can recombine in active layer 735. The recombination of electrons and holes can cause photon emission, thereby generating light. The wavelength and energy of the emitted photons can depend on the energy band gap between the valence band and the conduction band in active layer 735. For example, an InGaN active layer can emit green or blue light, while an AlInGaP active layer can emit red, orange, yellow, or green light. The emitted photons can propagate in many different directions and can be reflected by the mesa reflector and / or the back reflector and can be, for example, reflected from the Figure 7B The bottom side (e.g., substrate 715) shown in FIG is away from the LED 705. One or more other secondary optical components (such as a lens or grating) can be formed on the light emitting surface (such as substrate 715) to focus or collimate the emitted light and / or couple the emitted light into a waveguide.

[0099] A one-dimensional array or a two-dimensional array of the above-mentioned LEDs can be manufactured on a wafer to form a light source (e.g., light source 642). A driver circuit (e.g., driver circuit 644) can be manufactured on a silicon wafer, for example, using a CMOS process. The LEDs and driver circuits on the wafer can be diced and then bonded together, or can be bonded at the wafer level and then diced. Various bonding techniques can be used to bond the LEDs and driver circuits, such as adhesive bonding, metal-to-metal bonding, metal oxide bonding, wafer-to-wafer bonding, die-to-wafer bonding, hybrid bonding, etc.

[0100] Fig. 8A An example of a method for wafer-to-wafer bonding of an LED array according to some embodiments is shown. Fig. 8A In the example shown, the LED array 801 may include a plurality of LEDs 807 on a carrier substrate 805. The carrier substrate 805 may include various materials, such as GaAs, InP, GaN, AlN, sapphire, SiC, Si, etc. The LEDs 807 may be manufactured by, for example, growing various epitaxial layers, forming mesa structures, and forming electrical contacts or electrodes before performing bonding. The epitaxial layers may include various materials, such as GaN, InGaN, (AlGaIn)P, (AlGaIn)AsP, (AlGaIn)AsN, (AlGaIn)Pas, (Eu:InGa)N, (AlGaIn)N, etc., and may include an n-type layer, a p-type layer, and an active layer, the active layer including one or more heterostructures, such as one or more quantum wells or MQWs. The electrical contacts may include various conductive materials, such as metals or metal alloys.

[0101] Wafer 803 may include a base layer 809 having passive or active integrated circuits (e.g., driver circuit 811) fabricated thereon. Base layer 809 may include, for example, a silicon wafer. Driver circuit 811 may be used to control the operation of LED 807. For example, the driver circuit for each LED 807 may include a 2T1C pixel structure having two transistors and one capacitor. Wafer 803 may also include a bonding layer 813. Bonding layer 813 may include various materials, such as metals, oxides, dielectrics, CuSn, AuTi, etc. In some embodiments, a patterned layer 815 may be formed on the surface of bonding layer 813, wherein patterned layer 815 may include a metallic grid made of a conductive material such as Cu, Ag, Au, Al, etc.

[0102] The LED array 801 can be bonded to the wafer 803 via a bonding layer 813 or a patterned layer 815. For example, the patterned layer 815 can include metal pads or bumps made of various materials (such as CuSn, AuSn, or nanoporous Au) that can be used to align the LEDs 807 in the LED array 801 with the corresponding driver circuits 811 on the wafer 803. In one example, the LED array 801 can be directed toward the wafer 803 until the LEDs 807 contact the corresponding metal pads or bumps corresponding to the driver circuits 811. Some or all of the LEDs 807 can be aligned with the driver circuits 811 and can then be bonded to the wafer 803 via the patterned layer 815 by various bonding techniques (such as metal-to-metal bonding). After the LEDs 807 have been bonded to the wafer 803, the carrier substrate 805 can be removed from the LEDs 807.

[0103] Figure 8BAn example of a method for wafer-to-wafer bonding of an LED array according to some embodiments is shown. Figure 8B As shown, the first wafer 802 may include a substrate 804, a first semiconductor layer 806, an active layer 808, and a second semiconductor layer 810. The substrate 804 may include various materials, such as GaAs, InP, GaN, AlN, sapphire, SiC, Si, etc. The first semiconductor layer 806, the active layer 808, and the second semiconductor layer 810 may include various semiconductor materials, such as GaN, InGaN, (AlGaIn) P, (AlGaIn) AsP, (AlGaIn) AsN, (AlGaIn) Pas, (Eu: InGa) N, (AlGaIn) N, etc. In some embodiments, the first semiconductor layer 806 may be an n-type layer, and the second semiconductor layer 810 may be a p-type layer. For example, the first semiconductor layer 806 may be an n-type doped GaN layer (e.g., doped with Si or Ge), and the second semiconductor layer 810 may be a p-type doped GaN layer (e.g., doped with Mg, Ca, Zn, or Be). For example, the active layer 808 may include one or more GaN layers, one or more InGaN layers, one or more AlInGaP layers, etc. The active layer 808 may form one or more heterostructures, such as one or more quantum wells or MQWs.

[0104] In some embodiments, the first wafer 802 may further include a bonding layer. The bonding layer 812 may include various materials, such as metals, oxides, dielectrics, CuSn, AuTi, etc. In one example, the bonding layer 812 may include a p-contact and / or an n-contact (not shown). In some embodiments, other layers may also be included on the first wafer 802, such as a buffer layer between the substrate 804 and the first semiconductor layer 806. The buffer layer may include various materials, such as polycrystalline GaN or AlN. In some embodiments, a contact layer may be between the second semiconductor layer 810 and the bonding layer 812. The contact layer may include any suitable material for providing electrical contact to the second semiconductor layer 810 and / or the first semiconductor layer 806.

[0105] The first wafer 802 can be bonded to the wafer 803 including the driver circuit 811 and the bonding layer 813 as described above via the bonding layer 813 and / or the bonding layer 812. The bonding layer 812 and the bonding layer 813 can be made of the same material or different materials. The bonding layer 813 and the bonding layer 812 can be substantially flat. The first wafer 802 can be bonded to the wafer 803 by various methods (such as metal-to-metal bonding, eutectic bonding, metal oxide bonding, anodic bonding, thermocompression bonding, ultraviolet (UV) bonding and / or melt bonding).

[0106] like Figure 8BAs shown, the first wafer 802 can be bonded to the wafer 803 with the p-side (e.g., the second semiconductor layer 810) of the first wafer 802 facing down (i.e., toward the wafer 803). After bonding, the substrate 804 can be removed from the first wafer 802, and the first wafer 802 can then be processed from the n-side. For example, the processing can include forming a specific mesa shape for an individual LED, and forming an optical component corresponding to the individual LED.

[0107] Figure 9A-9D An example of a method for hybrid bonding of an LED array according to some embodiments is shown. Hybrid bonding may generally include wafer cleaning and activation, high precision alignment of contacts of one wafer with contacts of another wafer, dielectric bonding of dielectric materials at the wafer surface at room temperature, and metallic bonding of the contacts by an annealing process at elevated temperature. Fig.9A A substrate 910 is shown with passive or active circuits 920 fabricated thereon. Figure 8A-B As described, substrate 910 may include, for example, a silicon wafer. Circuit 920 may include a driver circuit for an LED array. The bonding layer may include a dielectric region 940 and a contact pad 930 connected to circuit 920 via an electrical interconnect 922. Contact pad 930 may include, for example, Cu, Ag, Au, Al, W, Mo, Ni, Ti, Pt, Pd, etc. The dielectric material in dielectric region 940 may include SiCN, SiO2, SiN, Al2O3, HfO2, ZrO2, Ta2O5, etc. The bonding layer may be planarized and polished using, for example, chemical mechanical polishing, wherein planarization or polishing may cause a depression (bowl-shaped profile) in the contact pad. The surface of the bonding layer may be cleaned and activated by, for example, an ion (e.g., plasma) or fast atom (e.g., Ar) beam 905. The activated surface may be atomically cleaned and reactive when the wafers are in contact, for example, at room temperature, for forming direct bonds between wafers.

[0108] Fig. 9B It is shown that the above reference includes Figure 7A-Figure 8BThe wafer 950 of the micro LED 970 array fabricated thereon. Wafer 950 may be a carrier wafer and may include, for example, GaAs, InP, GaN, AlN, sapphire, SiC, Si, etc. Micro LED 970 may include an n-type layer, an active region, and a p-type layer epitaxially grown on wafer 950. The epitaxial layer may include the various III-V semiconductor materials described above, and may be processed from the p-type layer side to etch a mesa structure in the epitaxial layer, such as a substantially vertical structure, a parabolic structure, a conical structure, etc. A passivation layer and / or a reflective layer may be formed on the sidewalls of the mesa structure. P-contacts 980 and n-contacts 982 may be formed in a dielectric material layer 960 deposited on the mesa structure, and may be electrically contacted with the p-type layer and the n-type layer, respectively. The dielectric material in the dielectric material layer 960 may include, for example, SiCN, SiO2, SiN, Al2O3, HfO2, ZrO2, Ta2O5, etc. The p-contact 980 and the n-contact 982 may include, for example, Cu, Ag, Au, Al, W, Mo, Ni, Ti, Pt, Pd, etc. The top surfaces of the p-contact 980, the n-contact 982, and the dielectric material layer 960 may form a bonding layer. The bonding layer may be planarized and polished using, for example, chemical mechanical polishing, where the polishing may cause depressions in the p-contact 980 and the n-contact 982. The bonding layer may then be cleaned and activated by, for example, an ion (e.g., plasma) or fast atom (e.g., Ar) beam 915. The activated surface may be atomically cleaned and may be reactive when the wafers are in contact, for example, at room temperature, for forming direct bonds between the wafers.

[0109] Fig. 9C A room temperature bonding process for dielectric materials bonded in a bonding layer is shown. For example, after a bonding layer including a dielectric region 940 and a contact pad 930 and a bonding layer including a p-contact 980, an n-contact 982, and a dielectric material layer 960 is surface activated, a wafer 950 and a micro-LED 970 can be inverted and contacted with a substrate 910 and a circuit formed thereon. In some embodiments, a compressive pressure 925 can be applied to the substrate 910 and the wafer 950 so that the bonding layers are pressed against each other. Due to the surface activation and the depressions in the contacts, the dielectric region 940 and the dielectric material layer 960 can be in direct contact due to surface attraction, and can react and form chemical bonds between them because the surface atoms can have dangling bonds and may be in an unstable energy state after activation. Therefore, the dielectric materials in the dielectric region 940 and the dielectric material layer 960 can be bonded together with or without heat treatment or pressure.

[0110] Fig.9DAn annealing process of the contacts bonded in the bonding layer is shown after the dielectric material in the bonding layer is bonded. For example, the contact pad 930 and the p-contact 980 or the n-contact 982 can be bonded together by annealing at a temperature of, for example, about 200° C.-400° C. or higher. During the annealing process, the heat 935 can cause the contacts to expand more than the dielectric material (due to different thermal expansion coefficients), and thus can close the recessed gap between the contacts so that the contact pad 930 and the p-contact 980 or the n-contact 982 can contact and can form a direct metal bond at the activated surface.

[0111] In some embodiments where the two bonded wafers include materials with different coefficients of thermal expansion (CTE), the dielectric material bonded at room temperature can help reduce or prevent misalignment of contact pads caused by different thermal expansion. In some embodiments, to further reduce or avoid misalignment of contact pads at high temperatures during annealing, trenches can be formed between micro-LEDs, between groups of micro-LEDs, etc., through part or all of the substrate prior to bonding.

[0112] After the microLED is bonded to the driver circuit, the substrate on which the microLED is fabricated can be thinned or removed, and various secondary optical components can be fabricated on the light-emitting surface of the microLED to, for example, extract, collimate, and redirect light emitted from the active area of ​​the microLED. In one example, a microlens can be formed on the microLED, wherein each microlens can correspond to a corresponding microLED and can help improve the light extraction efficiency and collimate the light emitted by the microLED. In some embodiments, the secondary optical components can be fabricated in the substrate or n-type layer of the microLED. In some embodiments, the secondary optical components can be fabricated in a dielectric layer deposited on the n-type side of the microLED. Examples of secondary optical components may include lenses, gratings, anti-reflective (AR) coatings, prisms, photonic crystals, and the like.

[0113] Fig.10 An example of an LED array 1000 having secondary optics fabricated thereon is shown in accordance with some embodiments. The LED array 1000 may be fabricated using the LED arrays described above with reference to, for example, Figures 8A-9D The LED chip or wafer is bonded to a silicon wafer including circuits fabricated thereon using any suitable bonding technique described. Fig.10 In the example shown, the LED array 1000 can be used as described above with reference to Figure 9A-9DThe LED array 1000 may include a substrate 1010, which may be, for example, a silicon wafer. An integrated circuit 1020 (such as an LED driver circuit) may be fabricated on the substrate 1010. The integrated circuit 1020 may be connected to a p-contact 1074 and an n-contact 1072 of a micro LED 1070 via an interconnect 1022 and a contact pad 1030, wherein the contact pad 1030 may form a metal bond with the p-contact 1074 and the n-contact 1072. The dielectric layer 1040 on the substrate 1010 may be bonded to the dielectric layer 1060 by fusion bonding.

[0114] The substrate (not shown) of the LED chip or wafer may be thinned or may be removed to expose the n-type layer 1050 of the micro-LEDs 1070. Various secondary optical components, such as spherical micro-lenses 1082, gratings 1084, micro-lenses 1086, anti-reflective layers 1088, etc., may be formed in or on top of the n-type layer 1050. For example, a spherical micro-lens array may be etched in the semiconductor material of the micro-LEDs 1070 using a grayscale mask and a photoresist having a linear response to exposure light, or using an etch mask formed by thermal reflowing of a patterned photoresist layer. Secondary optical components may also be etched in a dielectric layer deposited on the n-type layer 1050 using similar photolithography techniques or other techniques. For example, a micro-lens array may be formed in a polymer layer by thermal reflow of a polymer layer patterned using a binary mask. The microlens array in the polymer layer can be used as a secondary optical component or can be used as an etching mask to transfer the profile of the microlens array into the dielectric layer or semiconductor layer. The dielectric layer can include, for example, SiCN, SiO2, SiN, Al2O3, HfO2, ZrO2, Ta2O5, etc. In some embodiments, the micro-LED 1070 can have a plurality of corresponding secondary optical components, such as microlenses and anti-reflective coatings, microlenses etched in semiconductor materials and microlenses etched in dielectric material layers, microlenses and gratings, spherical lenses and aspherical lenses, etc. Fig.10 Three different secondary optics are shown in to illustrate some examples of secondary optics that may be formed on micro LEDs 1070, which does not necessarily mean that a different secondary optic is used simultaneously for each LED array.

[0115] Fig.11 An example of a display device 1100 including an array of three LEDs coupled to a waveguide is shown. The LEDs may be μLEDs. Fig.11As shown at the top of , display device 1100 may include wafer 1105, wafer 1110, and wafer 1115, which are mounted on backplane 1122 via I / O bumps. Wafers 1105, 1110, and 1115 may be LED wafers. Wafer 1105 may include an LED array configured to emit red light, for example Figure 5A Wafer 1110 may include an LED array configured to emit green light, for example Figure 5A Wafer 1115 may include an LED array configured to emit blue light, for example Figure 5A The blue light emitter 516 is shown in FIG. Figure 5A Each of the projection optics 520 shown can be a lens that collimates light from the red light emitter 512, the green light emitter 514, and the blue light emitter, respectively. Wafers 1105, 1110, and 1115 are configured to be coplanar along the z-direction, but can be staggered in any suitable configuration along the x-direction and / or the y-direction. A first additional layer 1125, such as a first RDL, can be disposed between wafer 1105 and backplane 1122. A second additional layer 1130, such as a second RDL, can be disposed between wafer 1110 and backplane 1122. A third additional layer 1135, such as a third RDL, can be disposed between wafer 1115 and backplane 1122. Backplane 1122 can have driver and graphics functions. The backplate 1122 may include a backplate wafer 1120 that is positioned below at least one of the wafers 1105 , 1110 , or 1115 and drives the wafers 1105 , 1110 , and 1115 .

[0116] Fig.11 The bottom shows the Fig.11 A cross-section of the display device 1100 is shown at the top. Fig.11 As shown at the bottom of the backplane 1122, a redistribution stack 1140 may be provided to allow the wafers 1105, 1110, and 1115 to dock with the backplane 1122, so that the wafers 1105, 1110, and 1115 do not need to be completely or precisely positioned on top of the backplane 1122. The redistribution stack 1140 may include one or more RDLs. I / O bumps 1145 may be provided to provide connections between the wafers 1105, 1110, and 1115 and the backplane 1122. Additional I / O bumps (not shown) may be provided on the underside of the backplane 1122 to provide connections between the backplane 1122 and a sensor aggregation chip (not shown), and to power an integrated circuit including the wafers 1105, 1110, and 1115.

[0117] In addition, if Fig.11 As shown at the bottom of the display device 1100, a spacer structure such as a spacer slice 1150 and / or a spacer column 1155 can be incorporated into a common display package 1160 of the display device 1100. The common display package 1160 also includes a backplane 1122. The spacer structure and the backplane 1122 together provide mechanical support and planar alignment for the wafers 1105, 1110, and 1115 arranged on the top surface of the display package 1160. For example, the spacer structure and the backplane 1122 can provide direct or indirect mechanical support. For example, the wafers 1105, 1110, and 1115 can be directly mounted on the backplane 1122 and at least one spacer structure. Alternatively, the wafers 1105, 1110, and 1115 can be indirectly mounted on the backplane 1122 and at least one spacer structure, so that one or more intermediate layers and / or components can exist between the wafers 1105, 1110, and 1115 and the backplane 1122 and at least one spacer structure.

[0118] The spacer slices 1150 and / or the spacer posts 1155 can be used to reduce the warpage of the display package 1160 and manage the thermal conductivity of the display package 1160. The performance of the microLEDs, especially the performance of the red microLEDs that may be included in the wafer 1105, is very sensitive to the junction temperature. In addition, the red microLEDs generate a lot of heat. In addition, placing the relatively small backplane wafer 1120 in the relatively large display package 1160 may cause high warpage in the display package 1160, which in turn deteriorates the coplanarity of the wafers 1105, 1110, and 1115 after the wafers 1105, 1110, and 1115 are mounted on top of the display package 1160. As discussed below, the spacer slices 1150 and / or the spacer posts 1155 can improve the internal thermal resistance of the display package 1160 and improve the planarity of the display package 1160. The spacer slices 1150 and / or the spacer posts 1155 may be unrelated to the function of the display package 1160 in establishing any analog current or digital signal, and may instead be passive components used to increase the thermal conductivity and mechanical stability of the display package 1160. Alternatively or additionally, various types of circuits may be added to the spacer slices 1150 and / or the spacer posts 1155. For example, the circuits may include active Si structures and / or passive components, such as capacitors, resistors, and / or inductors.

[0119] The display package 1160 includes a molding compound 1165. The molding compound 1165 may be selected to have sufficient mechanical strength, good adhesion to the package components, manufacturing and environmental chemical resistance, electrical resistance, low thermal expansion coefficient, high thermal stability and moisture resistance within the use temperature range. The molding compound 1165 may be made of any suitable material (e.g., thermoplastics, thermosetting polymers, elastomers, composite compounds and / or silicone compounds). For example, the molding compound 1165 may have a low thermal conductivity of about 1 W / m·K. In contrast, the spacer slice 1150 and / or the spacer column 1155 may have a high thermal conductivity, which improves the dissipation of heat generated by the micro-LEDs in the wafers 1105, 1110 and 1115. By replacing a portion of the molding compound 1165, the spacer slice 1150 and / or the spacer column 1155 can increase the thermal conductivity in the vertical direction (i.e., the z direction), so that more heat is transferred downward toward the printed circuit board or other substrate on which the display package 1160 is mounted. Furthermore, the spacer slices 1150 and / or spacer columns 1155 may increase thermal conductivity in the lateral direction (ie, xy plane) such that excess heat generated by the red micro LEDs within the wafer 1105 is distributed laterally, thereby increasing the effective area and efficiency of the frame in dissipating heat.

[0120] Fig.11 The spacer slices 1150 shown at the bottom can be "floating" so that they are not connected to the redistribution stack 1140 of the display package 1160. Alternatively, the spacer slices 1150 can have spacer vias and / or spacer bumps to connect to the redistribution stack 1140. The spacer slices 1150 can be made of various materials having a thermal conductivity of at least 50 W / m·K and a coefficient of thermal expansion (CTE) selected to maximize the overall planarity and / or thermal stability of the display package 1160. For example, the CTE of the spacer slices 1150 can be selected to be similar to the CTE of at least one of the surrounding materials. The CTE of the spacer slices 1150 can be within 1%, 5%, 10%, 20%, or 40% of the CTE of at least one of the surrounding materials. Some examples of materials that can be used to form the spacer slices 1150 include Si, Mo, AlN, Al2O3, and Cu. In some examples, the spacer slice 1150 can be made of Si to match the CTE of other Si components in the display device 1100. The spacer slice 1150 can have a height in the z direction that is similar to the height of the molding compound 1165 and / or the backplane wafer 1120. For example, the height of the spacer slice 1150 can be within 1%, 5%, or 10% of the height of the molding compound 1165 and / or the backplane wafer 1120. The width of the spacer slice 1150 in the x-direction and / or y-direction can be greater than the height in the z-direction. The spacer slice 1150 can have a size similar to the size of the backplane wafer 1120.

[0121] In some examples, the spacer column 1155 can be made of Cu or a material having properties similar to those of Cu. The spacer column 1155 can have a height along the z-direction that is similar to the height of the molding compound 1165 and / or the backplane wafer 1120. For example, the height of the spacer column 1155 can be within 1%, 5%, or 10% of the height of the molding compound 1165 and / or the backplane wafer 1120. The width of the spacer column 1155 along the x-direction and / or the y-direction can be less than the height of the spacer column 1155 along the z-direction.

[0122] Fig. 12A and Fig. 12B The above reference Fig.11 Examples of spacer posts that may be used to improve internal thermal resistance and planarity of display package 1160 are described. Fig. 12A An example of a spacer column 1255a is shown, which has a spacer bump 1285 to connect to the RDL 1275 within the display package. The spacer column 1255a can be formed on an under-bump metallization (UBM) 1270a. The RDL 1275 can be a metal layer positioned between the first dielectric layer 1280 and the second dielectric layer 1290. Alternatively, the spacer column 1255a can have a spacer via to connect to the RDL 1275 within the display package. In contrast, Fig. 12B An example of a spacer column 1225b is shown that is "floating" such that the spacer column 1225b is not connected to the RDL 1275 of the display package. This can save routing space within the display package.

[0123] Fig.13A and Fig. 13B The above reference Fig.11 , Fig. 12A and Fig. 12B Examples of cross-sectional shapes of spacer posts are described. Fig.13A An example of a spacer column 1335a having a circular cross-section is shown. The circular cross-section of the spacer column 1335a can minimize the wiring space used by the spacer column 1335a. In some examples, the spacer column 1335a can have a volume ratio of 25% within the display package. In contrast, Fig. 13BAn example of a spacer column 1335b having a square cross-section is shown. The square cross-section may have a generally square shape with rounded corners. The square cross-section of the spacer column 1335b may maximize the thermal conductivity of the display package because the spacer column 1335b occupies a larger portion of the volume of the display package, while the molding compound occupies a smaller portion of the volume of the display package. In some examples, the spacer column 1335b may have a volume ratio of 33% within the display package.

[0124] The molding compound within the display package can have a thermal conductivity between 0.9 W / m·K and 1.1 W / m·K, while if the spacer column is made of Cu, the spacer column has a thermal conductivity of 385 W / m·K. In the following description, D is defined as the diameter of the spacer column 1335a having a circular cross-section or the edge length of the spacer column 1335b having a square cross-section. In addition, P is defined as the spacing of the spacer columns within the display package. The effective thermal conductivity of the display package can be adjusted by changing the shape of the spacer column and / or the relationship between D and P. For a composite material including a spacer column 1335a having a circular cross-section and a diameter of D=0.5*P, the effective thermal conductivity is 77 W / m·K. For a composite material including a spacer column 1335b having a square cross-section and a diameter of D=0.5*P, the effective thermal conductivity is 92 W / m·K. For the composite material including spacer pillars 1335b having a square cross-section and a diameter of D=0.75*P, the effective thermal conductivity is 205 W / m·K.

[0125] Fig.14 1 is a simplified block diagram of an example electronic system 1400 for implementing an example near-eye display (e.g., HMD device) of some examples disclosed herein. The electronic system 1400 can be used as an electronic system for the HMD device or other near-eye display described above. In this example, the electronic system 1400 may include one or more processors 1410 and a memory 1420. The processor 1410 may be configured to execute instructions for performing operations at multiple components, and may be, for example, a general-purpose processor or a microprocessor suitable for implementation in a portable electronic device. The processor 1410 may be communicatively coupled to multiple components within the electronic system 1400. To achieve this communicatively coupling, the processor 1410 may communicate with other illustrated components across a bus 1440. The bus 1440 may be any subsystem suitable for transmitting data within the electronic system 1400. The bus 1440 may include multiple computer buses and additional circuits to transmit data.

[0126] Memory 1420 may be coupled to processor 1410. In some embodiments, memory 1420 may provide both short-term storage and long-term storage, and may be divided into several units. Memory 1420 may be volatile (such as static random access memory (SRAM) and / or dynamic random access memory (DRAM)) and / or non-volatile (such as read-only memory (ROM), flash memory, etc.). In addition, memory 1420 may include a removable storage device such as a secure digital (SD) card. Memory 1420 may provide storage of computer-readable instructions, data structures, program modules, and other data for electronic system 1400. In some embodiments, memory 1420 may be distributed in different hardware modules. A set of instructions and / or codes may be stored on memory 1420. The instructions may be in the form of executable code that may be executed by the electronic system 1400, and / or may be in the form of source code and / or installable code that, when compiled and / or installed on the electronic system 1400 (e.g., using any of a variety of commonly available compilers, installers, compression / decompression utilities, etc.), may be in the form of executable code.

[0127] In some embodiments, the memory 1420 may store a plurality of application modules 1422 to 1424, which may include any number of applications. Examples of applications may include gaming applications, conference applications, video playback applications, or other suitable applications. These applications may include depth sensing functions or eye tracking functions. The application modules 1422-1424 may include specific instructions to be executed by the processor 1410. In some embodiments, some applications or portions of the application modules 1422-1424 may be executed by other hardware modules 1480. In some embodiments, the memory 1420 may additionally include a secure memory, which may include additional security controls to prevent copying or other unauthorized access to secure information.

[0128] In some embodiments, the memory 1420 may include an operating system 1425 loaded therein. The operating system 1425 may be operable to initiate execution of instructions provided by the application modules 1422-1424 and / or manage other hardware modules 1480 and interfaces with the wireless communication subsystem 1430, which may include one or more wireless transceivers. The operating system 1425 may be adapted to perform other operations across components of the electronic system 1400, including threading, resource management, data storage control, and other similar functions.

[0129] The wireless communication subsystem 1430 may include, for example, an infrared communication device, a wireless communication device, and / or a chipset (such as, Device, IEEE 802.11 device, Wi-Fi device, WiMax device, cellular communication facility, etc.) and / or similar communication interfaces. The electronic system 1400 may include one or more antennas 1434 for wireless communication as part of the wireless communication subsystem 1430 or as a separate component coupled to any part of the system. Depending on the desired functionality, the wireless communication subsystem 1430 may include a separate transceiver to communicate with base transceiver stations and other wireless devices and access points, which may include communicating with different data networks and / or network types (such as, wireless wide area network (WWAN), wireless local area network (WLAN) or wireless personal area network (WPAN)). The WWAN may be, for example, a WiMax (IEEE 802.16) network. The WLAN may be, for example, an IEEE 802.11x network. The WPAN may be, for example, a Bluetooth network, IEEE 802.15x, or some other type of network. The techniques described herein may also be used for any combination of WWAN, WLAN, and / or WPAN. The wireless communication subsystem 1430 may allow data to be exchanged with a network, other computer systems, and / or any other device described herein. The wireless communication subsystem 1430 may include means for sending or receiving data (e.g., an identifier of the HMD device, location data, geographic maps, heat maps, photos, or videos) using an antenna 1434 and a wireless link 1432. The wireless communication subsystem 1430, the processor 1410, and the memory 1420 may together comprise at least a portion of one or more of the means for performing some of the functions disclosed herein.

[0130] Embodiments of the electronic system 1400 may also include one or more sensors 1490. The sensor 1490 may include, for example, an image sensor, an accelerometer, a pressure sensor, a temperature sensor, a proximity sensor, a magnetometer, a gyroscope, an inertial sensor (e.g., a module combining an accelerometer and a gyroscope), an ambient light sensor, or any other similar module operable to provide a sensing output and / or receive a sensing input, such as a depth sensor or a position sensor. For example, in some embodiments, the sensor 1490 may include one or more inertial measurement units (IMUs) and / or one or more position sensors. The IMU may generate calibration data based on measurement signals received from one or more position sensors, the calibration data indicating an estimated position of the HMD device relative to an initial position of the HMD device. The position sensor may generate one or more measurement signals in response to a movement of the HMD device. Examples of position sensors may include, but are not limited to, one or more accelerometers, one or more gyroscopes, one or more magnetometers, another suitable type of sensor that detects movement, a type of sensor used for error correction of the IMU, or any combination thereof. The position sensors may be located external to the IMU, internal to the IMU, or any combination thereof.At least some of the sensors may use structured light patterns for sensing.

[0131] The electronic system 1400 may include a display module 1460. The display module 1460 may be a near-eye display and may graphically present information from the electronic system 1400, such as images, videos, and various instructions, to a user. Such information may be derived from one or more application modules 1422-1424, a virtual reality engine 1426, one or more other hardware modules 1480, a combination thereof, or any other suitable means for parsing graphical content for a user (e.g., via an operating system 1425). The display module 1460 may use LCD technology, LED technology (including, for example, OLED, ILED, μLED, AMOLED, TOLED, etc.), light emitting polymer display (LPD) technology, or some other display technology.

[0132] The electronic system 1400 may include a user input / output module 1470. The user input / output module 1470 may allow a user to send an action request to the electronic system 1400. The action request may be a request to perform a specific action. For example, the action request may be to start or end an application, or to perform a specific action within an application. The user input / output module 1470 may include one or more input devices. Example input devices may include a touch screen, a touch pad, a microphone, a button, a dial, a switch, a keyboard, a mouse, a game controller, or any other suitable device for receiving an action request and transmitting the received action request to the electronic system 1400. In some embodiments, the user input / output module 1470 may provide tactile feedback to the user according to instructions received from the electronic system 1400. For example, tactile feedback may be provided when an action request is received or an action request has been performed.

[0133] The electronic system 1400 may include a camera 1450, which may be used to take photos or videos of the user, for example, to track the user's eye position. The camera 1450 may also be used to take photos or videos of the environment, for example, for VR applications, AR applications, or MR applications. The camera 1450 may include, for example, a complementary metal oxide semiconductor (CMOS) image sensor having millions or tens of millions of pixels. In some embodiments, the camera 1450 may include two or more cameras, which may be used to capture 3D images.

[0134] In some embodiments, the electronic system 1400 may include a plurality of other hardware modules 1480. Each of the other hardware modules 1480 may be a physical module within the electronic system 1400. Although each of the other hardware modules 1480 may be permanently configured as a structure, some of the other hardware modules 1480 may be temporarily configured to perform a specific function or be temporarily activated. Examples of other hardware modules 1480 may include, for example, an audio output and / or input module (e.g., a microphone or a speaker), a near field communication (NFC) module, a rechargeable battery, a battery management system, a wired / wireless battery charging system, and the like. In some embodiments, one or more functions of the other hardware modules 1480 may be implemented in software.

[0135] In some embodiments, the memory 1420 of the electronic system 1400 may also store a virtual reality engine 1426. The virtual reality engine 1426 may execute an application within the electronic system 1400 and receive position information, acceleration information, velocity information, predicted future position, or any combination thereof of the HMD device from various sensors. In some embodiments, the information received by the virtual reality engine 1426 may be used to generate a signal (e.g., a display instruction) for the display module 1460. For example, if the received information indicates that the user has looked to the left, the virtual reality engine 1426 may generate content for the HMD device that reflects the user's movement in the virtual environment. Additionally, the virtual reality engine 1426 may perform an action within the application in response to an action request received from the user input / output module 1470, and provide feedback to the user. The feedback provided may be visual feedback, auditory feedback, or tactile feedback. In some embodiments, the processor 1410 may include one or more GPUs that may execute the virtual reality engine 1426.

[0136] In various implementations, the hardware and modules described above can be implemented on a single device, or on multiple devices that can communicate with each other using wired or wireless connections. For example, in some implementations, some components or modules (e.g., GPU, virtual reality engine 1426, and applications (e.g., tracking applications)) can be implemented on a console separate from the head-mounted display device. In some implementations, a console can be connected to more than one HMD or can support more than one HMD.

[0137] In alternative configurations, different components and / or additional components may be included in the electronic system 1400. Similarly, the functionality of one or more components may be distributed among the components in a manner different from that described above. For example, in some embodiments, the electronic system 1400 may be modified to include other system environments, such as an AR system environment and / or an MR environment.

[0138] The methods, systems, and devices discussed above are examples. Various embodiments may omit, replace, or add various processes or components as appropriate. For example, in alternative configurations, the described methods may be performed in an order different from that described, and / or various stages may be added, omitted, and / or combined. In addition, the features described with respect to certain embodiments may be combined in various other embodiments. Different aspects and elements of the embodiments may be combined in a similar manner. In addition, technology is constantly evolving, and therefore many elements are examples, which do not limit the scope of the present disclosure to those specific examples.

[0139] Specific details are given in the description to provide a thorough understanding of the embodiments. However, embodiments may be implemented without these specific details. For example, in order to avoid obscuring the embodiments, well-known circuits, processes, systems, structures, and techniques have been shown without unnecessary details. This description only provides example embodiments and is not intended to limit the scope, applicability, or configuration of the present invention. Rather, the foregoing description of the embodiments will provide enabling descriptions (enabling descriptions) for implementing various embodiments to those skilled in the art. Various changes may be made in the functions and arrangements of elements without departing from the spirit and scope of the present disclosure.

[0140] In addition, some embodiments are described as processes, and the processes are depicted as flow charts or block diagrams. Although each can describe the operation as a sequential process, many operations can be performed in parallel or concurrently. In addition, the order of the operations can be rearranged. The process can have additional steps not included in the figure. In addition, the embodiments of the method can be implemented by hardware, software, firmware, middleware, microcode, hardware description language or any combination thereof. When implemented with software, firmware, middleware or microcode, the program code or code segment performing the associated task can be stored in a computer-readable medium such as a storage medium. The processor can perform the associated tasks.

[0141] It will be apparent to those skilled in the art that substantial variations may be made depending on specific requirements. For example, customized hardware or dedicated hardware may also be used, and / or specific elements may be implemented in hardware, software (including portable software, such as applets, etc.), or both. In addition, connections to other computing devices such as network input / output devices may be employed.

[0142] With reference to the accompanying drawings, the components that may include memory may include non-transitory machine-readable media. The terms "machine-readable medium" and "computer-readable medium" may refer to any storage medium that participates in providing data that enables a machine to operate in a particular manner. In the embodiments provided above, various machine-readable media may involve providing instructions / codes to a processing unit and / or other devices for execution. Additionally or alternatively, a machine-readable medium may be used to store and / or carry such instructions / codes. In many implementations, a computer-readable medium is a physical storage medium and / or a tangible storage medium. Such a medium may take a variety of forms, including but not limited to non-volatile media, volatile media, and transmission media. Common forms of computer-readable media include, for example, magnetic media and / or optical media (such as compact disks (CDs) or digital versatile disks (DVDs)), punch cards, paper tapes, any other physical media with hole patterns, RAM, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), FLASH-EPROM, any other memory chip or box, a carrier wave as described below, or any other medium from which a computer can read instructions and / or codes. A computer program product may include code and / or machine executable instructions, which may represent a procedure, function, subprogram, program, routine, application (App), subroutine, module, software package, class, or any combination of instructions, data structures, or program statements.

[0143] Those skilled in the art will appreciate that the information and signals used to transmit the messages described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0144] The terms "and" and "or" as used herein may include multiple meanings, which are also expected to depend at least in part on the context in which such terms are used. Generally, "or", if used in an associative list, such as A, B, or C, is intended to mean A, B, and C (used herein in an inclusive sense) as well as A, B, or C (used herein in an exclusive sense). In addition, the term "one or more" as used herein may be used to describe any feature, structure, or characteristic in a singular form, or may be used to describe a certain combination of features, structures, or characteristics. However, it should be noted that this is merely an illustrative example, and the subject matter claimed is not limited to this example. In addition, the term "at least one of...", if used in an associative list, such as A, B, or C, may be interpreted to mean any combination of A, B, and / or C, such as A, AB, AC, BC, AA, ABC, AAB, AABBCCC, etc.

[0145] In addition, although certain embodiments have been described using a specific combination of hardware and software, it should be appreciated that other combinations of hardware and software are possible. Certain embodiments may be implemented in hardware only, or in software only, or using a combination thereof. In one example, the software may be implemented using a computer program product comprising computer program code or instructions that may be executed by one or more processors for performing any or all of the steps, operations, or processes described in this disclosure, wherein the computer program may be stored on a non-transitory computer-readable medium. The various processes described herein may be implemented on the same processor or on different processors in any combination.

[0146] Where a device, system, component or module is described as being configured to perform certain operations or functions, such configuration may be accomplished, for example, by designing electronic circuits that perform the operations, by programming programmable electronic circuits (such as microprocessors) to perform the operations (such as by executing computer instructions or code), or by a processor or core programmed to execute code or instructions stored on a non-transitory memory medium, or any combination thereof. Processes may communicate using a variety of technologies (including, but not limited to, conventional technologies for inter-process communication), and different pairs of processes may use different technologies, or the same pair of processes may use different technologies at different times.

[0147] Therefore, the description and drawings should be regarded as illustrative rather than restrictive. However, it will be apparent that additions, subtractions, deletions and other modifications and changes may be made thereto without departing from the broader spirit and scope as set forth in the claims. Therefore, although specific embodiments have been described, these embodiments are not intended to be limiting. Various modifications and equivalents are within the scope of the appended claims.

Claims

1. A device comprising: A display package comprising a molding compound; a plurality of light emitting diode (LED) dies arranged on a top surface of the display package, wherein each LED die of the plurality of dies comprises a plurality of LEDs; a backplane wafer embedded within the molding compound of the display package, wherein the backplane wafer is electrically coupled to each of the plurality of LED wafers; and at least one spacer structure embedded in a molding compound of the display package, wherein: The backplane wafer and the at least one spacer structure together provide mechanical support and planar alignment for the plurality of LED wafers arranged on the top surface of the display package, The at least one spacer structure has a first thermal conductivity, and the molding compound has a second thermal conductivity lower than the first thermal conductivity; and The at least one spacer structure occupies a larger portion of the volume of the display package than the molding compound.

2. The device according to claim 1, wherein: The first thermal conductivity is at least 50 W / m·K.

3. The device according to claim 1 or 2, wherein: The at least one spacer structure includes a slice having a slice height approximately equal to a height of the backplane wafer and a slice width greater than the slice height.

4. The device according to claim 3, wherein: The slice is electrically connected to a redistribution layer (RDL) of the display package through at least one of a via or a bump.

5. The device according to claim 3, wherein: The slice is electrically isolated from a redistribution layer (RDL) of the display package.

6. The device according to claim 3, wherein: The slice includes at least one of Si, Mo, AlN, Al2O3 or Cu.

7. Apparatus according to any preceding claim, wherein: The at least one spacer structure includes a post having a post height approximately equal to a height of the backplane wafer and a post width less than the post height.

8. The device according to claim 7, wherein: The pillar is electrically connected to a redistribution layer (RDL) of the display package through at least one of a via or a bump.

9. The device according to claim 7, wherein: The pillars are electrically isolated from a redistribution layer (RDL) of the display package.

10. The device according to claim 7, wherein: The pillars include Cu.

11. The device according to claim 7, wherein: The cross-section of the column has a circular shape.

12. The device according to claim 7, wherein: The cross-section of the column has a square shape with rounded corners.

13. The apparatus according to claim 1, wherein: The at least one spacer structure includes a plurality of posts, wherein each post of the plurality of posts has a post height approximately equal to a height of the backplane wafer and a post width less than the post height.

14. The apparatus according to claim 13, wherein any one of the following is true: a) Among them, A cross-section of each of the plurality of pillars has a circular shape, and a diameter of each of the plurality of pillars is at least half of a pitch of the plurality of pillars; or b) wherein a cross-section of each of the plurality of pillars has a square shape with rounded corners, and an edge length of each of the plurality of pillars is at least half of a pitch of the plurality of pillars; or wherein a cross-section of each of the plurality of pillars has a square shape with rounded corners, and an edge length of each of the plurality of pillars is at least three quarters of a pitch of the plurality of pillars; or c) wherein a cross-section of each of the plurality of pillars has a circular shape, and a volume ratio of the plurality of pillars to the molding compound is at least 25%; or d) wherein a cross-section of each of the plurality of pillars has a square shape with rounded corners, and a volume ratio of the plurality of pillars to the molding compound is at least 33%; or e) wherein the display package has a third thermal conductivity of at least 77 W / m·K; or f) wherein the display package has a third thermal conductivity of at least 205 W / m·K.

15. The device of claim 1, further comprising a circuit connected to the at least one spacer structure; in this case, optionally, wherein: The circuit includes at least one of an active Si structure, a capacitor, a resistor, or an inductor.

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