Micro light emitting diode chip, display device, electronic device, wafer, driving backplane assembly and wafer assembly

Abstract

This application provides a micro light-emitting diode chip, a display device, an electronic device, a wafer, a driving backplane assembly, and a wafer assembly, relating to the field of electronic technology. The light-emitting device includes a conductive optical functional layer disposed on the side of the transparent electrode layer facing the driving backplane. The conductivity of the conductive optical functional layer ensures that the internal electrical connections of the light-emitting device are not affected. Furthermore, the light emission direction of the conductive optical functional layer is always towards the transparent electrode layer. That is, the conductive optical functional layer emits received photons towards the light emission direction of the light-emitting device. Therefore, the conductive optical functional layer also serves as a light-assisted functional layer for the light-emitting device, changing the optical path of the received photons and emitting them towards the light emission side of the light-emitting device. The function of the conductive optical functional layer varies depending on its placement, but it always aims to emit received photons towards the surface of the light-emitting device to improve the light extraction efficiency of the light-emitting device.

Description

Technical Field

[0001] This application relates to the field of electronic technology, and in particular to a micro light-emitting diode chip, a display device, an electronic device, a wafer, a driver backplane assembly, and a wafer assembly. Background Technology

[0002] With the development of microfabrication technology, micro light-emitting diodes (MicroLEDs) have become increasingly widely used in lighting and display fields due to their advantages such as high brightness, low power consumption, long lifespan, high stability, and small size. The advantages of MicroLEDs are particularly evident in applications requiring small dimensions and high resolution.

[0003] However, the refractive index of the semiconductor epitaxial layer in current mainstream Micro LED devices is relatively high, which means that a large number of photons excited inside the Micro LED device cannot be emitted out of the Micro LED device, thus affecting the light extraction efficiency of the Micro LED device. Summary of the Invention

[0004] This application provides a miniature light-emitting diode chip, a display device, an electronic device, a wafer, a driver backplane assembly, and a wafer assembly for improving the light extraction efficiency of miniature light-emitting diode devices.

[0005] A first aspect of this application provides a miniature light-emitting diode chip, which can be an illumination chip that emits a single color of light or a display chip that emits full-color light.

[0006] The miniature light-emitting diode (LED) chip includes a driving backplane and multiple light-emitting devices spaced apart on one side of the driving backplane, with electrical isolation between the multiple light-emitting devices. Each light-emitting device includes a bonding layer, a transparent electrode layer, an epitaxial light-emitting stack, and a first conductive optical functional layer stacked on top of each other. The bonding layer, transparent electrode layer, epitaxial light-emitting stack, and first conductive optical functional layer in adjacent light-emitting devices are electrically isolated. The bonding layer is electrically connected to the driving backplane and can serve as both a bonding connection layer and a pixel electrode for the light-emitting device. The epitaxial light-emitting stack is disposed between the bonding layer and the transparent electrode layer. The first conductive optical functional layer is disposed on the side of the transparent electrode layer facing the driving backplane; the light emission direction of the first conductive optical functional layer faces the transparent electrode layer. The function of the first conductive optical functional layer varies depending on its placement, but regardless of its placement on any layer, the light emission direction of the first conductive optical functional layer is always the same as the light emission direction of the light-emitting device.

[0007] In the micro LED chip provided in this application embodiment, the light-emitting device includes a first conductive optical functional layer. This first conductive optical functional layer is disposed on the side of the transparent electrode layer facing the driving backplane. The conductivity of the first conductive optical functional layer ensures that the internal electrical connections of the light-emitting device are not affected. The light-emitting devices are spaced apart to ensure that the first conductive optical functional layer only conducts electricity in the thickness direction, and has no conductivity between the light-emitting devices, thus ensuring that the independent pixel lighting function of the light-emitting device is not affected. Furthermore, the light emission direction of the first conductive optical functional layer is always towards the transparent electrode layer. That is, the first conductive optical functional layer emits the received photons towards the light emission direction of the light-emitting device. Therefore, the first conductive optical functional layer also serves as a light-assisted functional layer of the light-emitting device, changing the optical path of the received photons and emitting them towards the light emission side of the light-emitting device. The function of the first conductive optical functional layer varies according to its placement, but it always emits the received photons towards the surface of the light-emitting device to improve the light extraction efficiency of the light-emitting device.

[0008] In one possible implementation, a first conductive optical functional layer is disposed between the transparent electrode layer and the epitaxial light-emitting stack, i.e., above the epitaxial light-emitting stack. The first conductive optical functional layer diffracts light incident from the epitaxial light-emitting stack toward the transparent electrode layer. By disposing the first conductive optical functional layer above the epitaxial light-emitting stack, wave vector compensation can be provided for photons outside the total internal reflection angle, allowing photons that would otherwise be reflected into the light-emitting device to escape from the device surface through diffraction, increasing the probability of these upward-facing photons escaping the device and improving the light extraction efficiency. Furthermore, since the first conductive optical functional layer is disposed outside the epitaxial light-emitting stack, it does not affect the epitaxial growth of the stack, resulting in high process feasibility.

[0009] In one possible implementation, a first conductive optical functional layer is disposed between the epitaxial light-emitting stack and the driving backplane, i.e., below the epitaxial light-emitting stack. The first conductive optical functional layer reflects light emitted from the epitaxial light-emitting stack toward the side where the transparent electrode layer is located. By distributing a reflective first conductive optical functional layer below the epitaxial light-emitting stack, photons emitted downwards from the epitaxial light-emitting stack can be reflected toward the light-emitting side of the light-emitting device, increasing the probability of these downward-emitting photons escaping from the light-emitting device and thus improving the light extraction efficiency of the light-emitting device. Furthermore, since the first conductive optical functional layer is disposed outside the epitaxial light-emitting stack, it does not affect the epitaxial growth of the epitaxial light-emitting stack, resulting in high process feasibility.

[0010] In one possible implementation, the first conductive optical functional layer is disposed between the bonding layer and the driving backplane. By placing the first conductive optical functional layer between the bonding layer and the driving backplane, the entire conductive bonding layer can directly make ohmic contact with the epitaxial light-emitting stack, thereby improving the ohmic contact effect.

[0011] In one possible implementation, where the first conductive optical functional layer is disposed between the bonding layer and the driving backplane, the material of the first base layer is a dielectric material, and the material of the first through-post includes a conductive material. The first base layer in multiple light-emitting devices is a monolithic structure. In a micro LED chip, the first conductive optical functional layer located within different light-emitting devices is configured as a monolithic structure, but the single-pixel lighting function in different light-emitting devices remains unaffected by the isolation provided by the first base layer. In this case, the pixelation step of the first conductive optical functional layer can be omitted, allowing independent control of individual light-emitting devices, simplifying the manufacturing process and reducing the number of steps. Furthermore, the grating effect of the first conductive optical functional layer without pixelation is more pronounced, resulting in better reflection.

[0012] In one possible implementation, the first conductive optical functional layer is disposed between the bonding layer and the epitaxial light-emitting stack. In this case, the bonding layer is directly bonded to the driving backplane, ensuring a good bonding effect between the light-emitting device and the driving backplane. Furthermore, the first conductive optical functional layer is disposed adjacent to and below the epitaxial light-emitting stack. Light emitted downwards from the epitaxial light-emitting stack can be directly reflected by the first conductive optical functional layer to the light-emitting side of the light-emitting device after hitting the first conductive optical functional layer, reducing the photon transmission path, lowering light loss, and further improving the light extraction efficiency of the light-emitting device.

[0013] In one possible implementation, the light-emitting device further includes a pixel electrode disposed between the bonding layer and the epitaxial light-emitting stack; a first conductive optical functional layer is disposed between the pixel electrode and the bonding layer. In this case, the pixel electrode is in direct ohmic contact with the epitaxial light-emitting stack, which can improve the ohmic contact effect.

[0014] In one possible implementation, the light-emitting device further includes a pixel electrode disposed between the bonding layer and the epitaxial light-emitting stack; a first conductive optical functional layer is disposed between the pixel electrode and the epitaxial light-emitting stack. In this case, the first conductive optical functional layer is disposed adjacent to and below the epitaxial light-emitting stack. Light emitted downward from the epitaxial light-emitting stack can be directly reflected by the first conductive optical functional layer to the light-emitting side of the light-emitting device after hitting the first conductive optical functional layer, thereby reducing the photon transmission path, reducing light loss, and further improving the light extraction efficiency of the light-emitting device.

[0015] In one possible implementation, the first conductive optical functional layer includes a first base layer and a plurality of first through-posts, the first through-posts being disposed within the first base layer; the material of the first base layer and / or the first through-posts includes a conductive material, that is, at least one of the materials of the first base layer and the first through-posts includes a conductive material. The refractive index of the material of the first base layer is different from the refractive index of the material of the first through-posts. The inclusion of conductive materials in the first base layer and / or the first through-posts ensures the conductivity of the first conductive optical functional layer. Furthermore, configuring the first conductive optical functional layer as having a structure where the first through-posts penetrate the first base layer ensures the flatness of the first conductive optical functional layer, facilitating the placement of other film layers in the light-emitting device.

[0016] In one possible implementation, multiple first through-posts are arranged in a multi-row, multi-column, three-dimensional array. This three-dimensional array of first through-posts can enhance the reflectivity of the first conductive optical functional layer. Furthermore, when the first conductive optical functional layer is positioned between the bonding layer and the driving backplane, the first through-posts are arrayed in both the row and column directions, with adjacent first through-posts insulated from each other, which helps achieve electrical isolation in both the row and column directions.

[0017] In one possible implementation, multiple first through-pillars are arranged in a row and multiple columns or a column and multiple rows, forming a two-dimensional array. This two-dimensional array of first through-pillars can improve the diffraction effect of the first conductive optical functional layer.

[0018] In one possible implementation, the light-emitting device includes a first conductive optical functional layer disposed on the side of the epitaxial light-emitting stack facing the driving backplane. The device also includes a second conductive optical functional layer disposed between the transparent electrode layer and the epitaxial light-emitting stack. This second conductive optical functional layer diffracts light emitted from the epitaxial light-emitting stack toward the side where the transparent electrode layer is located. By placing the first conductive optical functional layer with reflective function below the epitaxial light-emitting stack, photons emitted downwards from the stack can be reflected towards the light-emitting side of the device, increasing the probability of these downward photons escaping the device. By placing the second conductive optical functional layer above the stack, wave vector compensation can be provided for photons outside the total internal reflection angle, allowing photons that would otherwise be reflected into the device to escape through diffraction, increasing the probability of these upward photons escaping the device. This further improves the light extraction efficiency of the light-emitting device.

[0019] In one possible implementation, multiple light-emitting devices include a first light-emitting device, a second light-emitting device, and a third light-emitting device. The first light-emitting device emits a first primary color light, the second light-emitting device emits a second primary color light, and the third light-emitting device emits a third primary color light. In this case, the miniature light-emitting diode chip can be used to achieve full-color displays, which is particularly useful in wearable electronic devices that require high light extraction efficiency.

[0020] A second aspect of this application provides a miniature light-emitting diode (LED) chip. The miniature LED chip can be a single-color LED chip or a display LED chip. The miniature LED chip includes a driving backplane and a plurality of light-emitting devices spaced apart on one side of the driving backplane. Each light-emitting device includes a bonding layer, a transparent electrode layer, an epitaxial light-emitting stack, and an optical functional layer. The bonding layer is electrically connected to the driving backplane. The epitaxial light-emitting stack is disposed between the bonding layer and the transparent electrode layer. The optical functional layer is disposed on the side of the transparent electrode layer away from the driving backplane. The optical functional layer is used to diffract light from the epitaxial light-emitting stack in a direction away from the transparent electrode layer. In the miniature LED chip provided by this application, the light-emitting device includes a diffraction grating layer. The diffraction grating layer provides wave vector compensation for photons outside the total internal reflection angle, allowing photons that would otherwise be reflected into the light-emitting device to escape from the surface of the light-emitting device through diffraction, increasing the probability of these upward-facing photons escaping the light-emitting device and improving the light extraction efficiency of the light-emitting device. Moreover, since the diffraction grating layer is located outside the epitaxial light-emitting stack, it will not affect the epitaxial growth of the epitaxial light-emitting stack, and the process is highly feasible.

[0021] In one possible implementation, the light-emitting device further includes a third conductive optical functional layer, disposed between the driving backplane and the epitaxial light-emitting stack. This third conductive optical functional layer reflects light emitted from the epitaxial light-emitting stack toward the side where the transparent electrode layer is located. Based on the diffraction grating layer, a third conductive optical functional layer with reflective function is further disposed below the epitaxial light-emitting stack. This reflects photons emitted downwards from the epitaxial light-emitting stack toward the light-emitting side of the device, increasing the probability of these downward-facing photons escaping the device and further improving the light extraction efficiency of the light-emitting device.

[0022] In one possible implementation, a third conductive optical functional layer is disposed between the driving backplane and the bonding layer. By placing the third conductive optical functional layer between the bonding layer and the driving backplane, the entire conductive bonding layer can directly make ohmic contact with the epitaxial light-emitting stack, thereby improving the ohmic contact effect.

[0023] In one possible implementation, the third conductive optical functional layer is disposed between the bonding layer and the epitaxial light-emitting stack. In this case, the bonding layer is directly bonded to the driving backplane, ensuring a good bonding effect between the light-emitting device and the driving backplane. Furthermore, the third conductive optical functional layer is positioned adjacent to and below the epitaxial light-emitting stack. Light emitted downwards from the epitaxial light-emitting stack can be directly reflected by the third conductive optical functional layer to the light-emitting side of the light-emitting device, reducing the photon transmission path, lowering light loss, and further improving the light extraction efficiency of the light-emitting device.

[0024] In one possible implementation, the light-emitting device further includes a pixel electrode disposed between the bonding layer and the epitaxial light-emitting stack; a third conductive optical functional layer is disposed between the pixel electrode and the bonding layer. In this case, the pixel electrode directly contacts the epitaxial light-emitting stack in an ohmic manner, which can improve the ohmic contact effect.

[0025] In one possible implementation, the light-emitting device further includes a pixel electrode disposed between the bonding layer and the epitaxial light-emitting stack; a third conductive optical functional layer is disposed between the pixel electrode and the epitaxial light-emitting stack. The third conductive optical functional layer is positioned immediately below the epitaxial light-emitting stack. Light emitted downwards from the epitaxial light-emitting stack can be directly reflected by the third conductive optical functional layer to the light-emitting side of the light-emitting device, reducing the photon transmission path, lowering light loss, and further improving the light extraction efficiency of the light-emitting device.

[0026] In one possible implementation, the third conductive optical functional layer includes a second base layer and a plurality of second through-posts, the second through-posts being disposed within the second base layer; the material of the second base layer and / or the second through-posts includes a conductive material, and the refractive index of the material of the second base layer is different from that of the material of the second through-posts. The inclusion of a conductive material in the second base layer and / or the second through-posts ensures the conductivity of the second conductive optical functional layer. Furthermore, configuring the second conductive optical functional layer as having second through-posts penetrating the second base layer ensures the flatness of the second conductive optical functional layer, facilitating the placement of other films in the light-emitting device.

[0027] In one possible implementation, where the third conductive optical functional layer is positioned between the bonding layer and the driving backplane, the second base layer is made of a dielectric material, and the second through-pillar is made of a conductive material. The second base layer in multiple light-emitting devices is a monolithic structure. In a micro-LED chip, the second conductive optical functional layer located within different light-emitting devices is configured as a monolithic structure. However, with the isolation provided by the second base layer, the single-pixel illumination function in different light-emitting devices remains unaffected. In this case, the pixelation step of the second conductive optical functional layer can be omitted, allowing independent control of individual light-emitting devices, simplifying the manufacturing process and reducing the number of steps. Furthermore, the grating effect of the second conductive optical functional layer without pixelation is more pronounced, resulting in better reflection.

[0028] A third aspect of this application provides a display device, which includes a micro light-emitting diode chip and a lens, the lens being disposed at the light-emitting side of the micro light-emitting diode chip; the micro light-emitting diode chip includes the micro light-emitting diode chip of either the first aspect or the second aspect. The display device provided by the third aspect of this application includes the micro light-emitting diode chip provided by the first aspect or the second aspect, and its beneficial effects are the same as those of the micro light-emitting diode chip, which will not be repeated here.

[0029] A fourth aspect of this application provides an electronic device, which includes an optical waveguide and a display device. The optical waveguide is used to receive image light emitted by the display device; the display device includes the display device of the third aspect.

[0030] A fifth aspect of this application provides a wafer comprising: an epitaxial light-emitting stacked layer, a bonding layer, and a first conductive optical functional layer. The epitaxial light-emitting stacked layer includes a first semiconductor layer, a second semiconductor layer, and an active layer, with the active layer disposed between the first and second semiconductor layers. The bonding layer is disposed on the side of the first semiconductor layer away from the active layer. The first conductive optical functional layer is stacked with the epitaxial light-emitting stacked layer, and the light emission direction of the first conductive optical functional layer is the direction from the active layer towards the second semiconductor layer. The wafer provided by this application embodiment can be used to fabricate light-emitting devices applied in the micro-light-emitting diode chips provided by this application embodiment; its beneficial effects can be found in the relevant description of the micro-light-emitting diode chips.

[0031] In one possible implementation, a first conductive optical functional film layer is disposed on the side of the second semiconductor film layer away from the bonding film layer. The first conductive optical functional film layer is used to diffract light from the epitaxial light-emitting stack directed toward the first conductive optical functional film layer toward the side away from the second semiconductor film layer.

[0032] In one possible implementation, a first conductive optical functional film layer is disposed between the bonding film layer and the epitaxial light-emitting stacked film layer. The first conductive optical functional film layer is used to reflect the light emitted from the epitaxial light-emitting stacked film layer toward the first conductive optical functional film layer toward the side where the second semiconductor film layer is located.

[0033] In one possible implementation, the first conductive optical functional film layer is disposed between the bonding film layer and the epitaxial light-emitting stacked film layer.

[0034] In one possible implementation, the wafer further includes a pixel electrode film layer disposed between the bonding film layer and the epitaxial light-emitting stacked film layer; a first conductive optical functional film layer is disposed between the pixel electrode film layer and the bonding film layer or the epitaxial light-emitting stacked film layer.

[0035] In one possible implementation, the first conductive optical functional film layer includes a third base layer and a plurality of third through pillars disposed within the third base layer; the material of the third base layer and / or the third through pillars includes a conductive material, and the refractive index of the material of the third base layer is different from that of the material of the third through pillars.

[0036] A sixth aspect of this application provides a driving backplane assembly, comprising: a driving backplane and a second conductive optical functional film layer. The second conductive optical functional film layer is disposed on one side of the driving backplane, and includes a fourth base layer and a plurality of fourth through-posts, the fourth through-posts being disposed within the fourth base layer. The material of the fourth base layer includes a dielectric material, and the material of the fourth through-posts includes a conductive material. The refractive index of the material of the fourth base layer is different from the refractive index of the material of the fourth through-posts. The driving backplane assembly provided by this application embodiment can be used to fabricate a micro light-emitting diode chip provided by this application embodiment, and its beneficial effects can be referred to the relevant description of the micro light-emitting diode chip.

[0037] A seventh aspect of this application provides a wafer assembly comprising: a wafer and a driving backplane, wherein the wafer and the driving backplane are bonded together. The wafer includes any of the wafers described in the fifth aspect; and / or, the driving backplane includes a driving backplane assembly described in the sixth aspect. Attached Figure Description

[0038] Figure 1A A schematic diagram of an AR glasses embodiment provided in this application;

[0039] Figure 1B An architectural diagram of a display device provided in an embodiment of this application;

[0040] Figure 1C This is a schematic diagram of the structure of a Micro LED chip provided in an embodiment of this application;

[0041] Figure 2This is a schematic diagram of another Micro LED chip provided in an embodiment of this application;

[0042] Figure 3A and Figure 3B This is a schematic diagram of the structure of another Micro LED chip provided in an embodiment of this application;

[0043] Figures 4A-4C A top view schematic diagram of a first conductive optical functional layer provided in an embodiment of this application;

[0044] Figure 4D A top view of a first conductive post provided in an embodiment of this application;

[0045] Figure 5A and Figure 5B This is a schematic diagram of the structure of another Micro LED chip provided in an embodiment of this application;

[0046] Figure 6 This is a schematic diagram of the structure of another Micro LED chip provided in an embodiment of this application;

[0047] Figure 7 This is a schematic diagram of the structure of another Micro LED chip provided in an embodiment of this application;

[0048] Figure 8 This is a schematic diagram of the structure of another Micro LED chip provided in an embodiment of this application;

[0049] Figure 9 This is a schematic diagram of the structure of another Micro LED chip provided in an embodiment of this application;

[0050] Figure 10 This is a schematic diagram of the structure of another Micro LED chip provided in an embodiment of this application;

[0051] Figure 11 This is a schematic diagram of the structure of another Micro LED chip provided in an embodiment of this application;

[0052] Figure 12 This is a schematic diagram of a wafer structure provided in an embodiment of this application;

[0053] Figure 13A and Figure 13B This is a schematic diagram of another wafer structure provided in an embodiment of this application;

[0054] Figure 14 This is a schematic diagram of another wafer structure provided in an embodiment of this application;

[0055] Figure 15This is a schematic diagram of another wafer structure provided in an embodiment of this application;

[0056] Figure 16 This is a schematic diagram of the structure of a drive backplane assembly provided in an embodiment of this application;

[0057] Figure 17 This is a schematic diagram of the structure of a wafer assembly provided in an embodiment of this application. Detailed Implementation

[0058] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0059] Hereinafter, the terms "second," "first," etc., are used for descriptive convenience only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "second," "first," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0060] In the embodiments of this application, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium. Furthermore, the term "coupled connection" can be a direct electrical connection or an indirect electrical connection through an intermediate medium. The term "contact" can be direct contact or indirect contact through an intermediate medium.

[0061] In this embodiment of the application, "and / or" describes the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following associated objects have an "or" relationship.

[0062] This application provides a terminal, which can be, for example, an electronic device, a light-emitting device, or any other product that requires a light source. Electronic devices include, for example, consumer electronics, home electronics, automotive electronics, or financial electronics. Consumer electronics include mobile phones, tablets, laptops, e-readers, personal computers (PCs), personal digital assistants (PDAs), desktop monitors, smart wearable products (e.g., smartwatches, smart bracelets), virtual reality (VR) electronic devices, augmented reality (AR) electronic devices, mixed reality (MR) electronic devices, projectors, micro-projectors, drones, etc. Home electronics include smart door locks, televisions, refrigerators, soymilk makers, or robot vacuum cleaners and other small rechargeable household appliances. Automotive electronics include in-vehicle navigation systems, in-vehicle DVDs, and augmented reality head-up displays (AR-HUDs) on the windshield. Financial electronics include ATMs and self-service electronic devices. Light-emitting devices can include flashlights, car lights, streetlights, and decorative lights. Other products that require a light source can include printers.

[0063] Taking an electronic device as an AR head-mounted display device as an example, an AR head-mounted display device may include AR glasses or AR helmets, etc. For ease of explanation, we will use an electronic device as an example of AR glasses.

[0064] Figure 1A This is a schematic diagram of an AR glasses provided in an embodiment of this application.

[0065] Figure 1A As shown, the AR glasses include a frame 101, temples 102, and lenses 103. The lenses 103 are mounted on the frame 101, and the temples 102 are connected to the frame 101. The temples 102 and the frame 101 allow the AR glasses to be worn in front of the user's eyes. A display device 200, which serves as an optical engine, is provided in the temples 102, which can display images or other content.

[0066] Lens 103 can be a prism-shaped spectacle lens based on an aspherical surface, a freeform surface, or its corresponding Fresnel surface. Lens 103 may include a lens body and a waveguide. The waveguide is disposed on the lens body. The lens body receives image light emitted by the display device 200 and transmits the received image light to the waveguide. The waveguide reflects the received effective image light to a preset position to form a virtual image, thereby creating an image in front of the user's eyes. For example, a light signal emitted by the display device 200 enters the lens body from near the temple 102, propagates through total internal reflection within the lens body, is reflected by the waveguide, and then coupled out to enter the user's retina, forming a virtual image on the retina, thus allowing the user to view the virtual image.

[0067] Micro light emitting diodes (Micro LEDs) have shown great potential in the display market due to their advantages such as high brightness, low power consumption, long lifespan, high stability, and small size, and can meet the needs of small-size and high-resolution scenarios.

[0068] The display device 200 in the temple 102 can display images or other content, for example, using a Micro LED chip. For instance, a Micro LED chip can serve as the core light-emitting device in AR display applications.

[0069] Figure 1B This is an architectural diagram of a display device provided in an embodiment of this application.

[0070] In some embodiments, such as Figure 1B As shown, the display device 200 includes a Micro LED chip 2 and a lens, with the lens disposed at the light-emitting side of the Micro LED chip 2. The Micro LED chip 2 may include, for example, a microdisplay chip, and the lens may include, for example, one or a group of convex lenses, one or a group of Fresnel lenses, one or a group of superlenses, or other optical elements. The lens projects and magnifies the image displayed on the Micro LED chip 2 and outputs it to the optical waveguide sheet.

[0071] Figure 1C This is a schematic diagram of the structure of a Micro LED chip provided in an embodiment of this application.

[0072] In some embodiments, such as Figure 1C As shown, the Micro LED chip 2 includes a driving backplate 10 and a plurality of light-emitting devices 20 disposed on one side of the driving backplate 10. The light-emitting devices 20 are disposed, for example, on the active surface of the driving backplate 10. The active surface of the driving backplate 10 can be understood, for example, as the direction of signal transmission of the driving circuit in the driving backplate 10, or as the side away from the side where the substrate is located in the driving backplate 10.

[0073] For example, the light-emitting device 20 includes a bonding layer 21, a first semiconductor layer 22, an active layer 23, a second semiconductor layer 24, and a transparent electrode layer 25 stacked together.

[0074] The first semiconductor layer 22, the active layer 23, and the second semiconductor layer 24 are typically obtained by doping group III-V semiconductor materials. However, group III-V semiconductor materials have a high refractive index, which prevents some photons emitted from the active layer 23 from escaping the surface of the light-emitting device 20, resulting in low light extraction efficiency, or external quantum efficiency, of the light-emitting device 20. Furthermore, the accumulation of photons inside the light-emitting device 20 also leads to severe heat generation and thermal degradation of the device.

[0075] Figure 2 This is a schematic diagram of another Micro LED chip provided in an embodiment of this application.

[0076] In some embodiments, such as Figure 2 As shown, the Micro LED chip 2 includes a driving backplane 10 and a light-emitting device 20, which is an LED device. The light-emitting device 20 includes a bonding layer 21, a distributed Bragg reflector (DBR), a first semiconductor layer 22, an active layer 23, a second semiconductor layer 24, and a transparent electrode layer 25.

[0077] By introducing a DBR structure with vias, such as a DBR structure comprising a dielectric stack of tantalum oxide / silicon oxide (Ta2O5 / SiO2) or silicon oxide / titanium oxide (SiO2 / TiO2), the bonding layer 21 achieves ohmic contact with the first semiconductor layer 22 through the via. The presence of the DBR structure can improve the reflectivity of the bottom surface of the LED light-emitting device, thereby improving light extraction efficiency. However, integrating the DBR structure inside the chip at the micron-scale of Micro LED and Mini LED chips presents significant technological challenges. Even when the DBR structure is integrated inside the chip, the reflection effect is relatively poor. Moreover, when forming the light-emitting device 20 through pixelation, the DBR structure also needs to be pixelated, which is not feasible.

[0078] This application provides a chip with high light extraction efficiency. The chip can be, for example, a Micro LED chip, a Mini LED chip, or the like. The chip can be a display chip including three primary color pixels, or a lighting chip including monochrome pixels. A Micro LED chip can be understood as a chip with a pixel pitch of less than 100µm. In this application embodiment, the pixel pitch of the Micro LED chip is, for example, less than 70µm, 50µm, 30µm, or 10µm.

[0079] Figure 3A and Figure 3B This is a schematic diagram of the structure of another Micro LED chip provided in an embodiment of this application.

[0080] In some embodiments, such as Figure 3A As shown, the Micro LED chip 2 includes a driving backplate 10 and a plurality of light-emitting devices 20, which are spaced apart on one side of the driving backplate 10. For example, the plurality of light-emitting devices 20 are spaced apart on the active side of the driving backplate 10.

[0081] The multiple light-emitting devices 20 may include, for example, a first light-emitting device, a second light-emitting device, and a third light-emitting device. The first light-emitting device emits a first primary color light, the second light-emitting device emits a second primary color light, and the third light-emitting device emits a third primary color light. The Micro LED chip 2 is a display chip. The multiple light-emitting devices 20 may also be used to emit light of the same color, and the Micro LED chip 2 is a chip that emits light of a single color.

[0082] The Micro LED chip 2 may also include a barrier 30, which is disposed between adjacent light-emitting devices 20 to reduce optical crosstalk between adjacent light-emitting devices 20. For example, the barrier 30 is disposed between the driving backplate 10 and the transparent electrode layer 25 of the light-emitting device 20.

[0083] For example, the light-emitting device 20 may include a bonding layer 21, a transparent electrode layer 25, an epitaxial light-emitting stack 26, and an optical functional layer, the optical functional layer including, for example, a first conductive optical functional layer 27. The bonding layer 21 is electrically connected to the driving backplane 10, and the epitaxial light-emitting stack 26 is disposed between the bonding layer 21 and the transparent electrode layer 25.

[0084] The transparent electrode layer 25 is made of a transparent conductive material, allowing light emitted from the epitaxial light-emitting stack 26 to be emitted. For example, the transparent electrode layer 25 may be made of a metal oxide. Examples include indium tin oxide (ITO), indium zinc oxide (IZO), aluminum-doped zinc oxide (ZnO:Al, AZO), and fluorine-doped tin oxide (SnO2:F, FTO). The transparent electrode layer 25 may be, for example, an N-type electrode layer used to inject electrons into the light-emitting device 20. In some embodiments, the transparent electrode layer 25 in the multiple light-emitting devices 20 included in the Micro LED chip 2 is a single, integrally formed structure.

[0085] The bonding layer 21 can serve as a pixel electrode for the light-emitting device 20, for example, as a P-type electrode layer, for injecting holes into the light-emitting device 20. Simultaneously, the bonding layer 21 also serves to bond with the driving backplane 10, achieving an electrical connection between the driving backplane 10 and the light-emitting device 20. For example, the material of the bonding layer 21 includes conductive materials such as chromium (Cr), titanium (Ti), nickel (Ni), platinum (Pt), gold (Au), copper (Cu), aluminum (Al), silver (Ag), tungsten titanate (TiW), tin (Sn), and transparent conductive materials.

[0086] Optionally, the epitaxial light-emitting stack 26 includes a first semiconductor layer 22, an active layer 23, and a second semiconductor layer 24. One of the first semiconductor layer 22 and the second semiconductor layer 24 is an N-type semiconductor layer, and the other is a P-type semiconductor layer. For example, the first semiconductor layer 22 is an N-type semiconductor layer, and the second semiconductor layer 24 is a P-type semiconductor layer. Alternatively, for example, the first semiconductor layer 22 is a P-type semiconductor layer, and the second semiconductor layer 24 is an N-type semiconductor layer.

[0087] For example, the first semiconductor layer 22 can be p-type doped or n-type doped in a group III-V semiconductor material to enable it to provide holes or electrons. Group III-V semiconductor materials include, for example, gallium oxide. The active layer 23 can employ a multiple quantum well (MQW) layer to generate photons and improve luminous efficiency. The second semiconductor layer 24 can be n-type doped or p-type doped in a semiconductor material to enable it to provide electrons or holes. For example, the substrates for the first semiconductor layer 22 and the second semiconductor layer 24 include gallium nitride (GaN), aluminum gallium indium phosphide (AlGaInP), aluminum gallium nitride (AlGaN), or gallium indium nitride (InGaN).

[0088] For example, the second semiconductor layer 24 is an N-type doped semiconductor layer, which forms an ohmic contact with the upper transparent electrode layer 25 and provides electrons to the lower active layer 23. The first semiconductor layer 22 is a P-type doped semiconductor layer, which forms an ohmic contact with the lower bonding layer 21 and provides holes to the upper active layer 23.

[0089] The epitaxial light-emitting stack 26 may also include an electron injection layer, a hole injection layer, etc. The structure of the epitaxial light-emitting stack 26 in related technologies is applicable to the embodiments of this application.

[0090] In the light-emitting device 20, the optical function and the transparent electrode layer 25 are stacked together. The light emission direction of the optical function is towards the transparent electrode layer 25 from the driving backplate 10. Alternatively, when the optical function is located on the side of the epitaxial light-emitting stack 26 facing the driving backplate 10, after receiving light emitted downwards from the epitaxial light-emitting stack 26, the optical function reflects the light along the direction from the driving backplate 10 towards the transparent electrode layer 25. For example, it reflects the light towards the light emission side. When the optical function is located on the side of the epitaxial light-emitting stack 26 facing the transparent electrode layer 25, after receiving light emitted upwards from the epitaxial light-emitting stack 26, the optical function diffracts the light along the direction from the driving backplate 10 towards the transparent electrode layer 25. For example, it diffracts the light towards the light emission side. In other words, regardless of which layer the optical function is located on, the light emission direction of the optical function is always the light emission direction of the light-emitting device 20.

[0091] In the Micro LED chip 2 provided in this embodiment, the light-emitting device 20 includes an optical function, and the light-emitting direction of the optical function is always the same as the light-emitting direction of the light-emitting device 20. Therefore, the optical function, as a light-assisted functional layer of the light-emitting device 20, can process the received light and then emit the light out of the light-emitting device 20. The function of the optical function varies depending on its location, but it always aims to emit the received light onto the surface of the light-emitting device 20 to improve the light extraction efficiency of the light-emitting device 20.

[0092] In one possible implementation, the optical functional layer in the light-emitting device 20 includes a first conductive optical functional layer 27. The first conductive optical functional layer 27 is disposed on the side of the transparent electrode layer 25 facing the driving backplate 10, and the light emission direction of the first conductive optical functional layer 27 is towards the transparent electrode layer 25. Alternatively, the first conductive optical functional layer 27 in the light-emitting device 20 can be understood as not only having a dimming effect but also a longitudinal conductive effect, capable of transmitting holes or electrons within the light-emitting device 20. For example, the first conductive optical functional layer 27 can be understood as a grating, a photonic crystal, a periodically arranged functional layer, etc.

[0093] The light-emitting device 20 includes a first conductive optical functional layer 27, which is disposed on the side of the transparent electrode layer 25 facing the driving backplate 10. The conductivity of the first conductive optical functional layer 27 ensures that the internal electrical connections of the light-emitting device 20 are not affected. The light-emitting devices 20 are spaced apart to ensure that the first conductive optical functional layer 27 is conductive only in the thickness direction, and not between the light-emitting devices 20, thus ensuring that the independent pixel lighting function of the light-emitting device 20 is not affected. Furthermore, the light emission direction of the first conductive optical functional layer 27 is always towards the transparent electrode layer 25. That is, the first conductive optical functional layer 27 emits the received photons towards the light emission direction of the light-emitting device 20. Therefore, the first conductive optical functional layer 27 also serves as a light-assisted functional layer of the light-emitting device 20, changing the optical path of the received photons and emitting them towards the light emission side of the light-emitting device 20. The function of the first conductive optical functional layer 27 varies depending on its placement, but it always emits the received photons towards the surface of the light-emitting device 20 to improve the light extraction efficiency of the light-emitting device 20.

[0094] In the first implementation, such as Figure 3A As shown, the first conductive optical functional layer 27 can be disposed between the epitaxial light-emitting stack 26 and the driving backplate 10.

[0095] The first conductive optical functional layer 27 is disposed below the epitaxial light-emitting stack 26. The first conductive optical functional layer 27 is used to reflect light emitted from the epitaxial light-emitting stack 26 toward the first conductive optical functional layer 27 toward the side where the transparent electrode layer 25 is located. At this time, the first conductive optical functional layer 27 can be understood as a reflective grating with conductive function.

[0096] By providing a first conductive optical functional layer 27 with reflective function below the epitaxial light-emitting stack 26, photons emitted downwards from the epitaxial light-emitting stack 26 can be reflected towards the light-emitting device 20, increasing the probability of these downward photons escaping from the light-emitting device 20, thereby improving the light extraction efficiency of the light-emitting device 20. Moreover, since the first conductive optical functional layer 27 is located outside the epitaxial light-emitting stack 26, it will not affect the epitaxial growth of the epitaxial light-emitting stack 26, resulting in high process feasibility.

[0097] In one alternative implementation, such as Figure 3A As shown, the Micro LED chip 2 includes multiple light-emitting devices 20, and the first conductive optical functional layers 27 in different light-emitting devices 20 are arranged at intervals and are insulated from each other.

[0098] In some embodiments, such as Figure 3AAs shown, the first conductive optical functional layer 27 is disposed between the bonding layer 21 and the epitaxial light-emitting stack 26. For example, the first conductive optical functional layer 27 is disposed between the bonding layer 21 and the first semiconductor layer 22. Thus, the bonding layer 21 is directly bonded to the driving backplate 10, ensuring the bonding effect between the light-emitting device 20 and the driving backplate 10. Moreover, the first conductive optical functional layer 27 is disposed adjacent to and below the epitaxial light-emitting stack 26. Light emitted downwards from the epitaxial light-emitting stack 26 can be directly reflected by the first conductive optical functional layer 27 to the light-emitting device 20 after it strikes the first conductive optical functional layer 27, reducing the photon transmission path, lowering light loss, and further improving the light extraction efficiency of the light-emitting device 20.

[0099] In other embodiments, such as Figure 3B As shown, the first conductive optical functional layer 27 is disposed between the bonding layer 21 and the driving backplate 10.

[0100] The structure of the first conductive optical functional layer 27 can be referred to the above description of the structure of the first conductive optical functional layer 27, and will not be repeated here. After the first conductive optical functional layer 27 is disposed between the bonding layer 21 and the driving backplate 10, the entire conductive bonding layer 21 can directly make ohmic contact with the epitaxial light-emitting stack 26, which can improve the ohmic contact effect.

[0101] Figures 4A-4C This is a top view schematic diagram of a first conductive optical functional layer provided in an embodiment of this application. Figure 4D This is a top view of a first conductive post provided in an embodiment of this application.

[0102] The structure of the first conductive optical functional layer 27, for example, is as follows: Figure 4A As shown, the first conductive optical functional layer 27 may include a first base layer 271 and a plurality of first through posts 272. The first through posts 272 are disposed within the first base layer 271 and penetrate the first base layer 271 along the thickness direction of the first base layer 271.

[0103] The material of the first base layer 271 may include a conductive material, or it may include a dielectric material. The material of the first through-post 272 may include a conductive material, or it may include a dielectric material. At least one of the materials of the first base layer 271 and the first through-post 272 includes a conductive material, so that the first conductive optical functional layer 27 has the function of conducting electricity along the thickness direction of the first conductive optical functional layer 27. That is, the material of the first base layer 271 includes a conductive material, and the material of the first through-post 272 includes a dielectric material, and electrical signal transmission is achieved through the first base layer 271. The electrical signal includes, for example, electrons or holes. Alternatively, the material of the first base layer 271 includes a dielectric material, and the material of the first through-post 272 includes a conductive material, and electrical signal transmission is achieved through the first through-post 272. Alternatively, the material of the first base layer 271 includes a conductive material, and the material of the first through-post 272 also includes a conductive material, and electrical signal transmission is achieved through the first base layer 271 and the first through-post 272.

[0104] Dielectric materials include, for example, silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiOxNy), titanium oxide (Ti2O3), aluminum oxide (Al2O3), etc., while conductive materials include, for example, indium tin oxide, gallium nitride (GaN), aluminum gallium indium phosphide, tungsten, aluminum, platinum, silver, gold, etc.

[0105] In some embodiments of this application, the refractive index of the material of the first base layer 271 in the first conductive optical functional layer 27 is different from the refractive index of the material of the first through-post 272. The refractive index of the material of the first base layer 271 may be greater than the refractive index of the material of the first through-post 272, or the refractive index of the material of the first base layer 271 may be less than the refractive index of the material of the first through-post 272.

[0106] This application embodiment does not limit the arrangement of the first through-post 272 in the first base layer 271, such as Figure 4A , Figure 4B and Figure 4C As shown, the arrangement pattern and spacing of the first through-post 272 can be adjusted according to the material, shape and size to prevent light from propagating in the first conductive optical functional layer 27, thereby achieving the purpose of reflecting light.

[0107] Optional, such as Figure 4A and Figure 4B As shown, multiple first through-posts 272 are arranged in multiple rows and columns within the plane of the first base layer 271. The multiple first through-posts 272 can be arranged in a triangular or square pattern, etc. Figure 4D As shown, the cross-sectional shape of the first through-post 272 can be any closed figure. For example, the cross-sectional shape of the first through-post 272 is... Figure 4B The circle shown Figure 4DThe trapezoid shown in (a) Figure 4D The rectangle shown in (b) is Figure 4D The triangle shown in (c) is Figure 4D The hexagon shown in (d) is an example.

[0108] Alternatively, you can choose, such as Figure 4C As shown, multiple first through-posts 272 are arranged in multiple rows and columns in the plane of the first base layer 271, with only one strip-shaped first through-post 272 in each row. Alternatively, multiple first through-posts 272 are arranged in one row and multiple columns in the plane of the first base layer 271, with only one strip-shaped first through-post 272 in each column.

[0109] The first through-post 272 can be a single-layer structure or a multi-layer structure. The thickness of the first through-post 272 can be less than, equal to or greater than the thickness of the first base layer 271. This application embodiment does not limit this.

[0110] The materials of the first base layer 271 and / or the first through-post 272 include conductive materials, which can ensure the conductivity of the first conductive optical functional layer 27. Based on this, setting the first conductive optical functional layer 27 to a structure in which the first through-post 272 penetrates the first base layer 271 can ensure the flatness of the first conductive optical functional layer 27, which facilitates the setting of other film layers in the light-emitting device 20.

[0111] Regarding the structure of the first conductive optical functional layer 27, or as an example, the first conductive optical functional layer 27 is a structure in which grating protrusions are formed on the conductive layer. Through the cooperation of the grating protrusions and the air gap, the effect of reflecting light is achieved. The specific structure of the first conductive optical functional layer 27 is not limited in the embodiments of this application. Gratings that can achieve conductive and light-reflecting functions along the thickness direction in related technologies are applicable to the embodiments of this application.

[0112] Figure 5A and Figure 5B This is a schematic diagram of the structure of another Micro LED chip provided in an embodiment of this application.

[0113] In some other embodiments, such as Figure 5A As shown, the light-emitting device 20 also includes a pixel electrode 28, which is disposed between the bonding layer 21 and the epitaxial light-emitting stack 26. A first conductive optical functional layer 27 is disposed between the pixel electrode 28 and the bonding layer 21. Therefore, the pixel electrode 28 directly contacts the epitaxial light-emitting stack 26 in an ohmic manner, which improves the ohmic contact effect. The structure of the first conductive optical functional layer 27 can be referred to the above description of its structure, and will not be repeated here.

[0114] In some other embodiments, such as Figure 5BAs shown, the light-emitting device 20 also includes a pixel electrode 28, which is disposed between the bonding layer 21 and the epitaxial light-emitting stack 26. A first conductive optical functional layer 27 is disposed between the pixel electrode 28 and the epitaxial light-emitting stack 26. Since the first conductive optical functional layer 27 is disposed adjacent to and below the epitaxial light-emitting stack 26, photons emitted downwards from the epitaxial light-emitting stack 26 can be directly reflected by the first conductive optical functional layer 27 to the light-emitting device 20 after striking it. This reduces the photon transmission path, lowers light loss, and further improves the light extraction efficiency of the light-emitting device 20.

[0115] The structure of the first conductive optical functional layer 27 can be referred to the above description of the structure of the first conductive optical functional layer 27, and will not be repeated here.

[0116] Figure 6 This is a schematic diagram of the structure of another Micro LED chip provided in an embodiment of this application.

[0117] In another alternative implementation, such as Figure 6 As shown, the Micro LED chip 2 includes multiple light-emitting devices 20, and the first conductive optical functional layer 27 is disposed between the bonding layer 21 and the driving backplate 10. The first conductive optical functional layer 27 in different light-emitting devices 20 is an integrally formed structure.

[0118] The material of the first base layer 271 is, for example, a dielectric material, and the material of the first through-post 272 includes a conductive material. The first base layer 271 in the plurality of light-emitting devices 20 is a monolithic structure, and the first through-posts 272 are spaced apart within the first base layer 271. The first conductive optical functional layer 27 can transmit electrical signals in the thickness direction through the first through-posts 272, and electrical isolation between the first through-posts 272 in different light-emitting devices 20 can be achieved through the first base layer 271. For example, the first through-posts 272 are not conductive in the plane of the first base layer 271.

[0119] In the Micro LED chip 2, the first conductive optical functional layer 27 located within different light-emitting devices 20 is configured as a single-piece structure. However, under the isolation of the first base layer 271, which is made of dielectric material, the single-pixel lighting function of the different light-emitting devices 20 is unaffected. In this case, the pixelation step of the first conductive optical functional layer 27 can be omitted, allowing independent control of each individual light-emitting device 20, simplifying the manufacturing process and reducing the number of steps. Moreover, the grating effect of the first conductive optical functional layer 27 without pixelation is more pronounced, resulting in better reflection.

[0120] Figure 7 This is a schematic diagram of the structure of another Micro LED chip provided in an embodiment of this application.

[0121] In the second implementation, such as Figure 7 As shown, the first conductive optical functional layer 27 is disposed between the epitaxial light-emitting stack 26 and the transparent electrode layer 25.

[0122] That is, the first conductive optical functional layer 27 is disposed above the epitaxial light-emitting stack 26. The first conductive optical functional layer 27 is used to diffract the light emitted from the epitaxial light-emitting stack 26 toward the first conductive optical functional layer 27 toward the side where the transparent electrode layer 25 is located. At this time, the first conductive optical functional layer 27 can be understood as a diffraction grating with conductive function.

[0123] By providing a first conductive optical functional layer 27 above the epitaxial light-emitting stack 26, wave vector compensation can be provided for photons outside the total internal reflection angle. This allows photons that would otherwise be reflected into the light-emitting device 20 to escape from the surface of the light-emitting device 20 through diffraction, increasing the probability of these upward photons escaping from the light-emitting device 20 and thus improving the light extraction efficiency of the light-emitting device 20. For example, the suppressed total internal reflection (Fresnel reflection) phenomenon can be used to diffract light that would otherwise not be emitted out of the light-emitting device 20. Moreover, since the first conductive optical functional layer 27 is located outside the epitaxial light-emitting stack 26, it does not affect the epitaxial growth of the epitaxial light-emitting stack 26, resulting in high process feasibility.

[0124] Figure 8 This is a schematic diagram of the structure of another Micro LED chip provided in an embodiment of this application.

[0125] In the third implementation, such as Figure 8 As shown, the Micro LED chip 2 includes both a reflective conductive grating located below the epitaxial light-emitting stack 26 and a diffraction conductive grating located above the epitaxial light-emitting stack 26.

[0126] For example, the Micro LED chip 2 includes a first conductive optical functional layer 27 and a second conductive optical functional layer 27'. The first conductive optical functional layer 27 is disposed between the epitaxial light-emitting stack 26 and the driving backplane 10, and is used to reflect light emitted from the epitaxial light-emitting stack 26 toward the first conductive optical functional layer 27 towards the side where the transparent electrode layer 25 is located. The second conductive optical functional layer 27' is disposed between the transparent electrode layer 25 and the epitaxial light-emitting stack 26, and is used to diffract light emitted from the epitaxial light-emitting stack 26 toward the second conductive optical layer 27' towards the side where the transparent electrode layer 25 is located.

[0127] By adjusting the shape, size, arrangement pattern, and spacing of the first through-posts 272 in the first conductive optical functional layer 27, the first conductive optical functional layer 27 can be made to have the effect of a reflective grating. Similarly, by adjusting the shape, size, arrangement pattern, and spacing of the first through-posts in the second conductive optical functional layer 27', the second conductive optical functional layer 27' can be made to have the effect of a diffraction grating.

[0128] The first conductive optical functional layer 27 can be Figure 3A , Figure 3B , Figure 5A , Figure 5B or Figure 6 Any one of the first conductive optical functional layers 27. Figure 8 This is just an illustration.

[0129] By providing a first conductive optical functional layer 27 with reflective function below the epitaxial light-emitting stack 26, photons emitted downwards from the epitaxial light-emitting stack 26 can be reflected upwards towards the light-emitting side of the light-emitting device 20, increasing the probability of these downward photons escaping from the light-emitting device 20. By providing a second conductive optical functional layer 27' above the epitaxial light-emitting stack 26, wave vector compensation can be provided for photons outside the total internal reflection angle, allowing photons that would otherwise be reflected into the light-emitting device 20 to escape from the surface of the light-emitting device 20 through diffraction, increasing the probability of these upward photons escaping from the light-emitting device 20. This further improves the light extraction efficiency of the light-emitting device 20.

[0130] Figure 9 and Figure 10 This is a schematic diagram of the structure of another Micro LED chip provided in an embodiment of this application.

[0131] In another possible implementation, such as Figure 9 As shown, the optical functional layer 27” in the light-emitting device 20 is not limited to having a conductive function; the optical functional layer 27” only needs to have an optical effect. For example, the optical functional layer 27” in the light-emitting device 20 can be a film layer with light diffraction function. For example, the optical functional layer 27” can be a grating, a photonic crystal, or a periodically arranged functional layer capable of diffracting photons. The optical functional layer 27” is disposed on the side of the transparent electrode layer 25 facing away from the driving backplate 10.

[0132] The structure of the optical functional layer 27” in this application embodiment is not limited, as long as it can achieve photon diffraction. The structure of the optical functional layer 27” can be the same as that of the first conductive optical functional layer 27 described above. For example, the optical functional layer 27” includes a fifth base layer and a plurality of fifth through pillars, the fifth through pillars being disposed within the fifth base layer; the refractive index of the material of the fifth base layer is different from that of the material of the fifth through pillars, and the materials of the fifth base layer and the fifth through pillars can be conductive materials, dielectric materials, semiconductor materials, etc.

[0133] In the Micro LED chip provided in this application embodiment, the light-emitting device 20 includes an optical functional layer 27". The optical functional layer 27” provides wave vector compensation for photons outside the total internal reflection angle among the received photons, so that photons that would otherwise be reflected into the light-emitting device 20 escape from the surface of the light-emitting device through diffraction, increasing the probability of these upward photons escaping from the light-emitting device 20, thereby improving the light extraction efficiency of the light-emitting device 20. Moreover, the optical functional layer 27” is disposed outside the epitaxial light-emitting stack 26, so it does not affect the epitaxial growth of the epitaxial light-emitting stack 26, and the process feasibility is high.

[0134] In some embodiments, such as Figure 10 As shown, the light-emitting device 20 also includes a third conductive optical functional layer 27”', which is disposed between the driving backplate 10 and the epitaxial light-emitting stack 26.

[0135] The structure of the third conductive optical functional layer 27”' can be the same as that of the first conductive optical functional layer 27 disposed below the epitaxial light-emitting stack 26. For example, the third conductive optical functional layer 27”' includes a second base layer and a plurality of second through pillars, the second through pillars being disposed within the second base layer; the material of the second base layer and / or the second through pillars includes a conductive material, and the refractive index of the material of the second base layer is different from that of the material of the second through pillars.

[0136] For example, the third conductive optical functional layer 27”' can be disposed between the driving backplate 10 and the bonding layer 21, or it can be disposed between the bonding layer 21 and the epitaxial light-emitting stack 26. If the light-emitting device 20 also includes a pixel electrode 28, the third conductive optical functional layer 27”' can be disposed between the pixel electrode 28 and the bonding layer 21, or between the pixel electrode 28 and the epitaxial light-emitting stack 26.

[0137] Based on the optical functional layer 27", a third conductive optical functional layer 27”' with reflective function is further provided below the epitaxial light-emitting stack 26. This can reflect the photons emitted downward by the epitaxial light-emitting stack 26 to the light-emitting device 20, increasing the probability of these downward photons escaping from the light-emitting device 20 and further improving the light extraction efficiency of the light-emitting device 20.

[0138] In some embodiments, the third conductive optical functional layer 27”' is disposed between the driving backplate 10 and the bonding layer 21, and the third conductive optical functional layer 27”' in the plurality of light-emitting devices 20 is an integrally formed structure.

[0139] For example, the material of the second base layer is a dielectric material, the material of the second through post includes a conductive material, and the second base layer in the multiple light-emitting devices 20 is an integrally formed structure.

[0140] In the Micro LED chip 2, the third conductive optical functional layer 27”' located within different light-emitting devices 20 is set as a single-piece structure. However, under the isolation of the second base layer, the single-pixel lighting function of different light-emitting devices 20 is not affected. At this time, the pixelation step of the third conductive optical functional layer 27”' can be omitted, and each light-emitting device 20 can be controlled independently, simplifying the process and reducing the number of process steps. Moreover, the grating effect of the third conductive optical functional layer 27”' without pixelation is more obvious, and the reflection effect is better.

[0141] Figure 11 This is a schematic diagram of the structure of another Micro LED chip provided in an embodiment of this application.

[0142] In some embodiments, such as Figure 11 As shown, the light-emitting device 20 also includes microlenses 29, which are disposed on the side of the transparent electrode layer 25 away from the driving backplate 10.

[0143] It can be based on any of the above-mentioned light-emitting device 20 structures by adding a microlens 29. Figure 11 This is just an illustration.

[0144] Microlens 29 includes collimating lens structures such as Fresnel lenses and convex lenses. Microlens 29 is used to optically control the photons emitted from the surface of the transparent electrode layer 25 by utilizing the principle of light diffraction, so that the light beam is concentrated within a range of ±30° of the central angle, thereby reducing optical crosstalk between adjacent light-emitting devices 20.

[0145] Figure 12 This is a schematic diagram of a wafer structure provided in an embodiment of this application.

[0146] This application also provides a wafer for fabricating the light-emitting device 20 in the Micro LED chip 2 described above. For example... Figure 12 As shown, the wafer includes an epitaxial light-emitting layer 260, a bonding layer 210, and a first conductive optical functional layer 270 stacked together. The epitaxial light-emitting layer 260, the bonding layer 210, and the first conductive optical functional layer 270 can, for example, be disposed on a carrier substrate.

[0147] The epitaxial light-emitting stack 260 includes a first semiconductor film layer 220, a second semiconductor film layer 240, and an active film layer 230, with the active film layer 230 disposed between the first semiconductor film layer 220 and the second semiconductor film layer 240. The first semiconductor film layer 220 and the second semiconductor film layer 240 are, for example, an N-type semiconductor film layer and a P-type semiconductor film layer, respectively.

[0148] The bonding film layer 210 is disposed on the side of the first semiconductor film layer 220 away from the active film layer 230, and the bonding film layer 210 is used to drive the backplane 10 to bond.

[0149] The first conductive optical functional film layer 270 and the epitaxial light-emitting film layer 260 are stacked together, and the light emission direction of the first conductive optical functional film layer 270 is the direction from the active film layer 230 toward the second semiconductor film layer 240.

[0150] In one possible implementation, such as Figure 12 As shown, the first conductive optical functional film layer 270 is disposed between the bonding film layer 210 and the epitaxial light-emitting stacked film layer 260. The first conductive optical functional film layer 270 is used to reflect the light emitted from the epitaxial light-emitting stacked film layer 260 toward the side where the second semiconductor film layer 240 is located.

[0151] For example, the first conductive optical functional film layer 270 is a grating structure that is conductive along its thickness direction and has a reflective function for received light. The structure of the first conductive optical functional film layer 270 can refer to the structure of the first conductive optical functional layer 27 disposed on the side of the epitaxial light-emitting stack 26 facing the driving backplate 10 described above.

[0152] Figure 13A and Figure 13B This is a schematic diagram of another wafer structure provided in an embodiment of this application.

[0153] In some embodiments, such as Figure 13A As shown, the wafer also includes a pixel electrode film layer 280, which is disposed between the bonding film layer 210 and the first semiconductor film layer 220.

[0154] like Figure 13AAs shown, the first conductive optical functional film layer 270 can be disposed between the bonding film layer 210 and the pixel electrode film layer 280.

[0155] Or, such as Figure 13B As shown, the first conductive optical functional film layer 270 can be disposed between the first semiconductor film layer 220 and the pixel electrode film layer 280.

[0156] Figure 14 This is a schematic diagram of another wafer structure provided in an embodiment of this application.

[0157] In another possible implementation, such as Figure 14 As shown, the first conductive optical functional film layer 270 is disposed on the side of the epitaxial light-emitting stacked film layer 260 away from the bonding film layer 210. The first conductive optical functional film layer 270 is used to diffract the light emitted from the epitaxial light-emitting stacked film layer 260 toward the side away from the second semiconductor film layer 240.

[0158] In some embodiments, the structure of the first conductive optical functional film layer 270 can be referenced to the above description of the first conductive optical functional layer 27. For example, the first conductive optical functional film layer 270 includes a third base layer and a plurality of third through-posts, the third through-posts being disposed within the third base layer; the material of the third base layer and / or the third through-posts includes a conductive material, and the refractive index of the material of the third base layer is different from the refractive index of the material of the third through-posts. By adjusting the structure of the third through-posts in the first conductive optical functional film layer 270, the first conductive optical functional film layer 270 can have diffraction or reflection functions to meet different needs.

[0159] Figure 15 This is a schematic diagram of another wafer structure provided in an embodiment of this application.

[0160] In another possible implementation, such as Figure 15 As shown, the epitaxial light-emitting stacked layer 260 is provided with a first conductive optical functional film layer 270 on the side away from the bonding film layer 210 and on the side of the epitaxial light-emitting stacked layer 260 facing the bonding film layer 210, respectively.

[0161] A first conductive optical functional film layer 270 disposed on the side of the epitaxial light-emitting stack 260 away from the bonding film layer 210 is used to diffract light incident from the epitaxial light-emitting stack 260 toward the first conductive optical functional film layer 270 toward the side away from the second semiconductor film layer 240. A first conductive optical functional film layer 270 disposed between the bonding film layer 210 and the epitaxial light-emitting stack 260 is used to reflect light incident from the epitaxial light-emitting stack 260 toward the first conductive optical functional film layer 270 toward the side where the second semiconductor film layer 240 is located.

[0162] The wafer provided in this application embodiment can be bonded to any type of driving backplane 10 in the art to form a wafer assembly, and then the wafer assembly is pixelated to obtain the Micro LED chip 2 provided in this application embodiment.

[0163] Figure 16 This is a schematic diagram of a drive backplane assembly provided in an embodiment of this application.

[0164] This application also provides a drive backplane assembly, such as... Figure 16 As shown, the drive backplane assembly includes a drive backplane 10 and a second conductive optical functional film layer 270'.

[0165] The second conductive optical functional film layer 270' is disposed on one side of the driving backplate 10, for example, the second conductive optical functional film layer 270' is disposed on the active surface side of the driving backplate 10. The second conductive optical functional film layer 270' includes a fourth base layer 271' and a plurality of fourth through posts 272'. The fourth through posts 272' are disposed within and penetrate the fourth base layer 271'. The material of the fourth base layer 271' includes a dielectric material, and the material of the fourth through posts 272' includes a conductive material. The refractive index of the material of the fourth base layer 271' is different from the refractive index of the material of the fourth through posts 272'.

[0166] The structural relationship between the fourth through column 272' and the fourth base layer 271' can be referred to the above-mentioned structural relationship between the first through column 272 and the first base layer 271, and will not be repeated here.

[0167] The driving backplane 10 may include, for example, a substrate, a front end of line (FEOL) layer, and a back end of line (BEOL) layer. The FEOL layer may include, for example, transistors in a pixel circuit for driving the light-emitting device 20, and the BEOL layer may include, for example, interconnect traces that interconnect the transistors in the FEOL layer to form the pixel circuit. After forming the BEOL layer, a second conductive optical functional film layer 270' may be formed, and a second conductive post 272' in the second conductive optical functional film layer 270' is electrically connected to a signal port in the BEOL layer.

[0168] The driving backplane assembly provided in this application embodiment can be bonded to any epitaxial wafer in the art to form a wafer assembly, and then the wafer assembly is pixelated to obtain the Micro LED chip 2 provided in this application embodiment.

[0169] Figure 17 This is a schematic diagram of the structure of a wafer assembly provided in an embodiment of this application.

[0170] This application also provides a wafer assembly, such as... Figure 17 As shown, the wafer assembly includes a wafer and a driving backplane, which are bonded together. The wafer in the wafer assembly may include any of the wafers described above, and / or the driving backplane in the wafer assembly may include the driving backplane assembly described above. For example, the bonding film layer 210 in the wafer is bonded to the second conductive optical functional film layer 270' in the driving backplane assembly, thereby achieving an electrical connection between the bonding film layer 210 and the second conductive post 272'.

[0171] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A miniature light-emitting diode chip, characterized in that, The miniature light-emitting diode chip includes: Drive backplane; Multiple light-emitting devices are spaced apart on one side of the driving backplate; each light-emitting device includes a bonding layer, a transparent electrode layer, an epitaxial light-emitting stack, and a first conductive optical functional layer; the bonding layer is electrically connected to the driving backplate, the epitaxial light-emitting stack is disposed between the bonding layer and the transparent electrode layer, and the first conductive optical functional layer is disposed on the side of the transparent electrode layer facing the driving backplate; the light emission direction of the first conductive optical functional layer is towards the transparent electrode layer.

2. The micro light-emitting diode chip according to claim 1, characterized in that, The first conductive optical functional layer is disposed between the transparent electrode layer and the epitaxial light-emitting stack. The first conductive optical functional layer is used to diffract the light emitted from the epitaxial light-emitting stack toward the first conductive optical functional layer toward the side where the transparent electrode layer is located.

3. The miniature light-emitting diode chip according to claim 1, characterized in that, The first conductive optical functional layer is disposed between the epitaxial light-emitting stack and the driving backplate. The first conductive optical functional layer is used to reflect the light emitted by the epitaxial light-emitting stack toward the first conductive optical functional layer toward the side where the transparent electrode layer is located.

4. The micro light-emitting diode chip according to claim 3, characterized in that, The first conductive optical functional layer is disposed between the bonding layer and the driving backplate.

5. The micro light-emitting diode chip according to claim 3, characterized in that, The first conductive optical functional layer is disposed between the bonding layer and the epitaxial light-emitting stack; or, The light-emitting device further includes a pixel electrode disposed between the bonding layer and the epitaxial light-emitting stack; the first conductive optical functional layer is disposed between the pixel electrode and the bonding layer or the epitaxial light-emitting stack.

6. The micro light-emitting diode chip according to any one of claims 1-5, characterized in that, The first conductive optical functional layer includes a first base layer and a plurality of first through-posts, the first through-posts being disposed within the first base layer; the material of the first base layer and / or the first through-posts includes a conductive material, and the refractive index of the material of the first base layer is different from the refractive index of the material of the first through-posts.

7. The micro light-emitting diode chip according to claim 6, characterized in that, When the first conductive optical functional layer is disposed between the bonding layer and the driving backplate, the material of the first base layer is a dielectric material, the material of the first through post includes a conductive material, and the first base layer in the plurality of light-emitting devices is an integrally formed structure.

8. The micro light-emitting diode chip according to any one of claims 3-7, characterized in that, The light-emitting device further includes a second conductive optical functional layer, which is disposed between the transparent electrode layer and the epitaxial light-emitting stack. The second conductive optical functional layer is used to diffract light emitted from the epitaxial light-emitting stack toward the second conductive optical functional layer toward the side where the transparent electrode layer is located.

9. The micro light-emitting diode chip according to any one of claims 1-8, characterized in that, The plurality of light-emitting devices include a first light-emitting device, a second light-emitting device, and a third light-emitting device, wherein the first light-emitting device is used to emit a first primary color light, the second light-emitting device is used to emit a second primary color light, and the third light-emitting device is used to emit a third primary color light.

10. A miniature light-emitting diode chip, characterized in that, The miniature light-emitting diode chip includes: Drive backplane; Multiple light-emitting devices are spaced apart on one side of the driving backplate; each light-emitting device includes a bonding layer, a transparent electrode layer, an epitaxial light-emitting stack, and an optical functional layer; the bonding layer is electrically connected to the driving backplate, the epitaxial light-emitting stack is disposed between the bonding layer and the transparent electrode layer, and the optical functional layer is disposed on the side of the transparent electrode layer away from the driving backplate, the optical functional layer being used to diffract the light emitted from the epitaxial light-emitting stack in a direction away from the transparent electrode layer.

11. The micro light-emitting diode chip according to claim 10, characterized in that, The light-emitting device further includes a third conductive optical functional layer, which is disposed between the driving backplate and the epitaxial light-emitting stack. The third conductive optical functional layer is used to reflect the light emitted by the epitaxial light-emitting stack toward the third conductive optical functional layer toward the side where the transparent electrode layer is located.

12. The micro light-emitting diode chip according to claim 11, characterized in that, The third conductive optical functional layer is disposed between the bonding layer and the driving backplate.

13. The micro light-emitting diode chip according to claim 11, characterized in that, The third conductive optical functional layer is disposed between the bonding layer and the epitaxial light-emitting stack; or, The light-emitting device further includes a pixel electrode disposed between the bonding layer and the epitaxial light-emitting stack; the third conductive optical functional layer is disposed between the pixel electrode and the bonding layer or the epitaxial light-emitting stack.

14. The micro light-emitting diode chip according to any one of claims 11-13, characterized in that, The third conductive optical functional layer includes a second base layer and a plurality of second through-posts, the second through-posts being disposed within the second base layer; the material of the second base layer and / or the second through-posts includes a conductive material, and the refractive index of the material of the second base layer is different from the refractive index of the material of the second through-posts.

15. The micro light-emitting diode chip according to claim 14, characterized in that, When the third conductive optical functional layer is disposed between the bonding layer and the driving backplate, the material of the second base layer is a dielectric material, the material of the second through post includes a conductive material, and the second base layer in the plurality of light-emitting devices is an integrally formed structure.

16. A display device, characterized in that, It includes a chip and a lens, the lens being disposed at the light-emitting side of the chip; the chip includes a micro light-emitting diode chip as described in any one of claims 1-15.

17. An electronic device, characterized in that, The device includes an optical waveguide and a display device, wherein the optical waveguide is used to receive image light emitted by the display device; the display device includes the display device as described in claim 16.

18. A wafer, characterized in that, The wafer includes: An epitaxial light-emitting stacked layer includes a first semiconductor film layer, a second semiconductor film layer, and an active film layer, wherein the active film layer is disposed between the first semiconductor film layer and the second semiconductor film layer; A bonding film layer is disposed on the side of the first semiconductor film layer away from the active film layer; A first conductive optical functional film layer is stacked with the epitaxial light-emitting film layer; the light emission direction of the first conductive optical functional film layer is the direction from the active film layer toward the second semiconductor film layer.

19. The wafer according to claim 18, characterized in that, The first conductive optical functional film layer is disposed on the side of the second semiconductor film layer away from the bonding film layer. The first conductive optical functional film layer is used to diffract the light from the epitaxial light-emitting stack directed toward the first conductive optical functional film layer in a direction away from the second semiconductor film layer.

20. The wafer according to claim 18, characterized in that, The first conductive optical functional film layer is disposed between the bonding film layer and the epitaxial light-emitting stacked film layer. The first conductive optical functional film layer is used to reflect the light emitted by the epitaxial light-emitting stacked film layer toward the first conductive optical functional film layer toward the side where the second semiconductor film layer is located.

21. The wafer according to claim 20, characterized in that, The first conductive optical functional film layer is disposed between the bonding film layer and the epitaxial light-emitting stacked film layer; or, The wafer further includes a pixel electrode film layer, which is disposed between the bonding film layer and the first semiconductor film layer; the first conductive optical functional film layer is disposed between the pixel electrode film layer and the bonding film layer or the first semiconductor film layer.

22. The wafer according to any one of claims 18-21, characterized in that, The first conductive optical functional film layer includes a third base layer and a plurality of third through pillars, wherein the third through pillars are disposed within the third base layer; the material of the third base layer and / or the third through pillars includes a conductive material, and the refractive index of the material of the third base layer is different from that of the material of the third through pillars.

23. A drive backplane assembly, characterized in that, The drive backplane assembly includes: Drive backplane; A second conductive optical functional film layer is disposed on one side of the drive backplate; the second conductive optical functional film layer includes a fourth base layer and a plurality of fourth through-posts, the fourth through-posts being disposed within the fourth base layer; the material of the fourth base layer includes a dielectric material, the material of the fourth through-posts includes a conductive material, and the refractive index of the material of the fourth base layer is different from the refractive index of the material of the fourth through-posts.

24. A wafer assembly, characterized in that, The wafer assembly includes: a wafer and a driving backplane, wherein the wafer and the driving backplane are bonded together; The wafer includes the wafer as described in any one of claims 18-22; And / or, The drive backplane includes the drive backplane assembly as described in claim 23.

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