Micro-LED element and electronic device

Abstract

The invention discloses a Micro-LED element and an electronic device, which are applied to the technical field of micro light-emitting diodes, and the metasurface is prepared by the following method: determining the phase information of each region on the surface of the light-emitting side of an LED main body structure; compensating each piece of phase information based on the reference phase, and determining a compensation phase of the nanostructure unit corresponding to each region; all the phase information is combined with the corresponding compensation phase to enable the wavefront phases of all the areas to be consistent; determining a deflection phase corresponding to each nanostructure unit under the target deflection angle; superposing the deflection phase and the compensation phase, and determining the actual phase of each nanostructure unit; and determining unit structure information of the corresponding nanostructure unit according to the actual phase. The metasurface can have the effects of collimating and deflecting the light beams at the same time, the DBR structure can be thinned or even avoided, element heating is reduced, and light extraction efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of micro-light-emitting diode technology, and in particular to a Micro-LED element and an electronic device. Background Technology

[0002] In recent years, GaN-based Micro-LEDs (Micro Light-Emitting Diodes) have become core components of next-generation display technologies due to their advantages such as high brightness, high efficiency, and long lifespan. In applications such as Augmented Reality (AR) and Virtual Reality (VR), higher requirements are placed on the beam quality and directivity of Micro-LEDs.

[0003] In existing technologies, a common approach to achieving beam deflection in Micro-LEDs is to add a Distributed Bragg Reflector (DBR) structure to the light-emitting surface to collimate the beam, allowing it to be emitted approximately like a plane wave. Then, beam deflection is achieved by manipulating the beam using a metasurface. Undeniably, the number of DBR layers does affect the quality of beam deflection, but multiple DBR layers lead to problems such as severe heat generation in Micro-LED devices and a significant reduction in light extraction efficiency.

[0004] Therefore, how to reduce the heat generation of Micro-LEDs that require beam deflection and improve the light extraction efficiency is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a Micro-LED element that can reduce element heat generation and improve light extraction efficiency while achieving beam deflection; another purpose of this invention is to provide an electronic device with low heat generation and high light extraction efficiency.

[0006] To address the aforementioned technical problems, the present invention provides a Micro-LED element, comprising:

[0007] LED main structure;

[0008] A metasurface located on the light-emitting side of the LED main structure; the metasurface comprises multiple nanostructure units distributed in an array, and the metasurface is prepared by the following method:

[0009] Determine the phase information of each region on the light-emitting side surface of the LED main structure;

[0010] Based on the reference phase, each of the phase information is compensated to determine the compensation phase of the corresponding nanostructure unit in each region; after combining each of the phase information with the corresponding compensation phase, the wavefront phase of each region is made consistent.

[0011] Determine the deflection phase corresponding to each nanostructure unit at the target deflection angle;

[0012] The actual phase of each nanostructure unit is determined by superimposing the deflection phase and the compensation phase.

[0013] The unit structure information of the corresponding nanostructure unit is determined based on the actual phase, so as to determine the structure of the metasurface based on the unit structure information.

[0014] Optionally, determining the phase information of each region on the light-emitting side surface of the LED main structure includes:

[0015] Obtain the overall phase information of the light-emitting side surface of the LED main structure;

[0016] The overall phase information is sampled based on the period size of the nanostructure unit to determine the phase information of each region.

[0017] Optionally, the compensation phase for each of the phase information is determined based on a reference phase, including:

[0018] Using the phase information of the center point of the light-emitting side surface of the LED main structure as the reference phase, compensation is performed on each of the phase information based on the reference phase to determine the compensation phase of the corresponding nanostructure unit in each region.

[0019] Optionally, determining the deflection phase corresponding to each nanostructure unit at the target deflection angle includes:

[0020] The deflection phase of each nanostructure unit at the target deflection angle was calculated based on the generalized Snell's law model.

[0021] Optionally, determining the unit structure information of the corresponding nanostructure unit based on the actual phase, and determining the structure of the metasurface based on the unit structure information, includes:

[0022] Based on the actual phase, select unit structure information corresponding to the actual phase from the structure library; the structure library includes the correspondence between the unit structure information and the actual phase;

[0023] The structure of the metasurface is determined based on the unit structure information of the nanostructure units corresponding to each region.

[0024] Optionally, the metasurface design method further includes:

[0025] Constructing multiple nanostructure units;

[0026] The geometric parameters of each nanostructure unit are scanned to determine the corresponding unit structure information;

[0027] The phase distribution of the nanostructure units at the target wavelength is obtained under the structural information of each unit, and the structure library is established.

[0028] Optionally, the LED main body structure includes:

[0029] A mirror layer, a p-type doped layer, a quantum well layer, and an n-type doped layer are sequentially arranged along the thickness direction; the metasurface is located on the side of the n-type doped layer away from the mirror layer.

[0030] Optionally, the LED main structure further includes a DBR layer, which is located on the surface of the n-type doped layer away from the mirror layer, and the metasurface is located on the surface of the DBR layer away from the mirror layer.

[0031] Optionally, the number of periods in the DBR layer is no more than 5.

[0032] This application also provides an electronic device including a Micro-LED element as described in any of the preceding claims.

[0033] The present invention provides a Micro-LED element, comprising: an LED main structure; a metasurface located on the light-emitting side of the LED main structure; the metasurface comprising a plurality of nanostructure units arranged in an array, the metasurface being fabricated by the following method: determining the phase information of each region on the light-emitting side surface of the LED main structure; compensating each phase information based on a reference phase to determine the compensated phase of the nanostructure unit corresponding to each region; combining each phase information with the corresponding compensated phase to make the wavefront phase of each region consistent; determining the deflection phase corresponding to each nanostructure unit at a target deflection angle; superimposing the deflection phase and the compensated phase to determine the actual phase of each nanostructure unit; determining the unit structure information of the corresponding nanostructure unit based on the actual phase, so as to determine the structure of the metasurface based on the unit structure information.

[0034] By first determining the compensation phase, then the deflection phase, and finally combining the two phases to determine the actual phase, the structure of the metasurface is determined. This allows the metasurface to simultaneously collimate and deflect the light beam. By combining these two functions into a single metasurface, the metasurface can replace the function of the DBR structure. This allows for the thinning or even elimination of the DBR structure, reducing the thickness of the light-emitting side structure of the LED main body. As a result, while achieving beam deflection, it reduces component heating and improves light extraction efficiency.

[0035] The present invention also provides an electronic device that has the same beneficial effects as described above, which will not be described in detail here. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the structure of a Micro-LED element provided in an embodiment of the present invention;

[0038] Figure 2 This is a front view schematic diagram of a specific Micro-LED element provided in an embodiment of the present invention;

[0039] Figure 3 for Figure 2 A top-view structural diagram;

[0040] Figure 4 This is a distribution diagram of the radius and phase of nanostructure units in the structure library;

[0041] Figure 5 The wavefront phase diagram is shown for the case where the DBR period is 2 and the surface has not passed through the metasurface.

[0042] Figure 6 The wavefront phase diagram is shown for the case where the DBR period is 3 and the surface has not passed through the metasurface.

[0043] Figure 7 The wavefront phase diagram is shown for the case of passing through a metasurface when the DBR period is 2.

[0044] Figure 8 The wavefront phase diagram is shown for the case of passing through a metasurface when the DBR period is 3.

[0045] Figure 9 The image shows the far-field image of a metasurface with a conventional beam deflected by 30° when the DBR period is 2.

[0046] Figure 10 The image shows the far-field image of a metasurface with a DBR period of 3 and a conventional beam deflected by 30°.

[0047] Figure 11 The image is the far-field image of the metasurface in this embodiment when the DBR period is 2.

[0048] Figure 12The image is the far-field image of the metasurface in this embodiment when the DBR period is 3.

[0049] Figure 13 The image is the far-field image of the metasurface in this embodiment when the DBR period is 4.

[0050] Figure 14 This is a comparison of the efficiency of a conventional beam deflection metasurface and the metasurface in this embodiment when deflected by 30°.

[0051] In the figure: 1. Mirror layer, 2. p-type doped layer, 3. Quantum well layer, 4. n-type doped layer, 5. DBR layer, 51. First dielectric layer, 52. Second dielectric layer, 6. Metasurface, 61. Nanostructure unit. Detailed Implementation

[0052] The core of this invention is to provide a Micro-LED element. In existing technologies, a common approach to achieving beam deflection in Micro-LEDs is to add a DBR (Distributed Bragg Reflector) structure to the light-emitting surface to collimate the beam, allowing it to be emitted approximately like a plane wave. Then, beam deflection is achieved by manipulating the beam using a metasurface. Undeniably, the number of DBR layers does affect the quality of beam deflection, but multiple DBR layers lead to problems such as severe heat generation and a significant reduction in light extraction efficiency in Micro-LED devices.

[0053] The present invention provides a Micro-LED element comprising: an LED main structure; a metasurface located on the light-emitting side of the LED main structure; the metasurface comprising multiple nanostructure units arranged in an array, the metasurface being fabricated by the following method: determining the phase information of each region on the light-emitting side surface of the LED main structure; compensating each phase information based on a reference phase to determine the compensated phase of the nanostructure unit corresponding to each region; combining each phase information with the corresponding compensated phase to make the wavefront phase of each region consistent; determining the deflection phase corresponding to each nanostructure unit at a target deflection angle; superimposing the deflection phase and the compensated phase to determine the actual phase of each nanostructure unit; determining the unit structure information of the corresponding nanostructure unit based on the actual phase, so as to determine the structure of the metasurface based on the unit structure information.

[0054] By first determining the compensation phase, then the deflection phase, and finally combining the two phases to determine the actual phase, the structure of the metasurface is determined. This allows the metasurface to simultaneously collimate and deflect the light beam. By combining these two functions into a single metasurface, the metasurface can replace the function of the DBR structure. This allows for the thinning or even elimination of the DBR structure, reducing the thickness of the light-emitting side structure of the LED main body. As a result, while achieving beam deflection, it reduces component heating and improves light extraction efficiency.

[0055] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] Example 1

[0057] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a Micro-LED element provided in an embodiment of the present invention.

[0058] See Figure 1 In this embodiment, the Micro-LED element includes: an LED main structure; a metasurface 6 located on the light-emitting side of the LED main structure; the metasurface 6 includes a plurality of nanostructure units 61 arranged in an array, and the metasurface 6 is prepared by the following method: determining the phase information of each region on the light-emitting side surface of the LED main structure; compensating each of the phase information based on a reference phase to determine the compensated phase of the nanostructure unit 61 corresponding to each region; combining each of the phase information with the corresponding compensated phase to make the wavefront phase of each region consistent; determining the deflection phase corresponding to each nanostructure unit 61 at a target deflection angle; superimposing the deflection phase with the compensated phase to determine the actual phase of each nanostructure unit 61; determining the unit structure information of the corresponding nanostructure unit 61 according to the actual phase, so as to determine the structure of the metasurface 6 according to the unit structure information.

[0059] The aforementioned LED main structure is the primary light-emitting structure in Micro-LED elements, and its details will be described in detail in the following embodiments, and will not be repeated here. The light-emitting side of this LED main structure is provided with a metasurface 6. Metasurface 6 is an artificial electromagnetic material composed of subwavelength structural units, which can overcome the physical limitations of traditional optical materials and achieve free control over the propagation behavior of light waves. Through carefully designed subwavelength structures to generate discrete phase abrupt changes, the wavefront distribution of light waves can be precisely manipulated at the nanoscale, thereby achieving special optical effects such as beam deflection and polarization conversion. Compared with traditional optical devices, metasurface 6 has significant advantages such as ultra-thinness, low loss, and easy integration, providing a new technical path for next-generation miniaturized and integrated optical systems.

[0060] In this embodiment, the metasurface 6 needs to simultaneously collimate and deflect the light beam, combining these two functions into a single layer. The structure of the metasurface 6 is typically composed of periodically distributed nanostructure units 61. These nanostructure units 61 can be cylindrical or any other arbitrary shape, without specific limitations. By adjusting the structural parameters of the nanostructure units 61 at different positions within the metasurface 6, such as height, diameter, and spacing, the phase of the light emitted from different positions can be adjusted; that is, the phase at different positions of the metasurface 6 corresponds to the size of the nanostructure unit 61 at that position. Specifically, in this embodiment, the actual phase at different positions of the metasurface 6 is determined to determine the size parameters of the corresponding nanostructure unit 61, thereby determining the structure of the entire metasurface 6.

[0061] In this embodiment, when determining the actual phase corresponding to each position of the metasurface 6, it is necessary to first determine the phase information of each region on the light-emitting side surface of the LED main structure without the metasurface 6. These regions are areas pre-defined on the light-emitting side surface of the LED main structure, and these regions also correspond to the pre-defined regions of the metasurface 6. In this embodiment, it is first necessary to obtain the phase information of each region on the light-emitting side surface of the LED main structure without the metasurface 6, so as to determine the specific structure of the metasurface 6 based on this phase information.

[0062] In this embodiment, determining the phase information of each region may specifically include: acquiring the overall phase information of the light-emitting surface of the LED main structure; sampling the overall phase information according to the period size of the nanostructure unit 61 to determine the phase information of each region. The overall phase information can be obtained based on FDTD (Finite-Difference Time-Domain). That is, in this embodiment, FDTD can first be used to acquire the overall phase information of the Micro-LED light-emitting surface, and then, in this embodiment, the overall phase information can be sampled according to the period size of the nanostructure unit 61. During this sampling process, the spacing between each sampling point needs to be related to the period size of the nanostructure unit 61. The phase information acquired at each sampling point is the phase information of the region to which that sampling point belongs, and each region can correspond to one or more nanostructure units 61.

[0063] After determining the phase information of each region, it is necessary to compensate for each phase information based on the reference phase to determine the compensated phase of the nanostructure unit 61 corresponding to each region. Generally, in this embodiment, the difference between the phase information corresponding to each region and the reference phase is determined by phase subtraction, and this difference is used as the compensated phase corresponding to the nanostructure unit 61 in each region. In this embodiment, the phase information combined with the corresponding compensated phase makes the wavefront phase of each region consistent. That is, when the phase of the light emitted from each region on the light-emitting side surface of the LED main structure is combined with the compensated phase corresponding to each region, the wavefront phase of each region can be made equal to the reference phase. This means that the wavefront phase of each region is consistent after combining the phase information of each region with the corresponding compensated phase. Consistent wavefront phase means that the emitted light beam has been collimated.

[0064] Specifically, in determining the compensation phase in this embodiment, it may include: using the phase information of the center point of the light-emitting side surface of the LED main structure as a reference phase, compensating for each of the phase information based on the reference phase, and determining the compensation phase of the nanostructure unit 61 corresponding to each region. That is, to facilitate the calculation of the compensation phase, this embodiment specifically uses the phase information of the center point of the light-emitting side surface of the LED main structure as the reference phase. Accordingly, when the phase of the light emitted from each region of the light-emitting side surface of the LED main structure is combined with the compensation phase corresponding to each region, the wavefront phase of each region can be made consistent with the phase of the center point of the light-emitting side surface of the LED main structure, thereby achieving collimation of the light emitted by the LED main structure. The phase of the center point can be obtained based on the above sampling.

[0065] Since the metasurface 6 can deflect light, different deflection angles require each region of the metasurface 6 to have a corresponding phase to correspond to the structure of different nanostructure units 61. In this embodiment, the phase required for light deflection in each region of the metasurface 6 is called the deflection phase. In this embodiment, the deflection angle corresponding to the Micro-LED element, i.e., the target deflection angle, needs to be determined first. Then, based on the target deflection angle, the deflection phase corresponding to each nanostructure unit 61 is determined. Based on this deflection phase, the light transmitted through the metasurface 6 can be deflected at the target angle, realizing the beam deflection process.

[0066] Specifically, in this embodiment, the deflection phase corresponding to each nanostructure unit 61 at the target deflection angle can be calculated based on the generalized Snell's law model. For details regarding the generalized Snell's law, please refer to existing technologies; it will not be elaborated upon here.

[0067] In this embodiment, after determining the compensation phase and deflection phase, the deflection phase and compensation phase corresponding to the same nanostructure unit 61 are superimposed. Specifically, this can be done by phase addition to determine the actual phase corresponding to each nanostructure unit 61. Combining the specific positions of each nanostructure unit 61 on the metasurface 6, the actual phase distribution of the entire metasurface 6 can be obtained.

[0068] In this embodiment, the unit structure information of each nanostructure unit 61 is determined based on the actual phase corresponding to each nanostructure unit 61. This unit structure information may include parameters such as the size and height of the corresponding nanostructure unit 61. Combined with the specific position of each nanostructure unit 61 on the metasurface 6, the structure of the metasurface 6 can be determined. Since the actual phase corresponding to the specific structure of the metasurface 6 is specifically formed by the superposition of the compensation phase and the deflection phase, and the compensation phase can be used to achieve collimation of the beam by the metasurface 6, and the deflection phase can be used to achieve deflection of the beam by the metasurface 6, the structure of the metasurface 6 obtained based on the above actual phase can simultaneously achieve collimation and deflection of the beam, ensuring that the emitted light has high quality while achieving large-angle beam deflection.

[0069] In this embodiment, after determining the structure of the metasurface 6, it is necessary to prepare the metasurface 6 of the structure on the light-emitting side of the LED main structure according to the structure in order to achieve the above-mentioned function.

[0070] Specifically, in determining the structure of the metasurface 6 in this embodiment, the process may include: selecting unit structure information corresponding to the actual phase from a structure library; the structure library includes the correspondence between the unit structure information and the actual phase; and determining the structure of the metasurface 6 based on the unit structure information of the nanostructure units 61 corresponding to each region. The aforementioned structure library is a pre-established database containing the correspondence between the unit structure information of nanostructure units 61 and the actual phase. The unit structure information of the nanostructure unit 61 characterizes the specific structure of that nanostructure unit 61, such as diameter and height. The structure library also stores the phase corresponding to the nanostructure unit 61 of the aforementioned structure, i.e., the actual phase. Once the actual phase corresponding to a certain nanostructure unit 61 in the metasurface 6 is determined, the structure corresponding to that nanostructure unit 61, i.e., the unit structure information, can be determined based on the structure library. By combining the unit structure information of all nanostructure units 61 with the specific position of the nanostructure units 61 in the metasurface 6, the structure of the metasurface 6 can be determined, enabling the metasurface 6 prepared based on this structure to transmit high-quality light with a target deflection angle.

[0071] In this embodiment, the above-mentioned structure library can be pre-established. The specific process includes: constructing multiple nanostructure units 61; scanning the geometric parameters of each nanostructure unit 61 to determine the corresponding unit structure information; obtaining the phase distribution of the nanostructure unit 61 under the target wavelength under the unit structure information, and establishing the structure library.

[0072] In this embodiment, multiple nanostructure units 61 are first constructed, each with its own corresponding unit structure information. Then, FDTD (Fixed-Difference Transmission Theory) is used to scan the geometric parameters of each constructed nanostructure unit 61 to obtain the light transmittance and phase distribution of the nanostructure unit 61 at the target wavelength under different geometric parameters, thus establishing a structure library. The set of multiple geometric parameters corresponding to one nanostructure unit 61 constitutes the aforementioned unit structure information, the aforementioned target wavelength is the wavelength of the light emitted by the LED main structure, and the aforementioned phase distribution corresponds to the aforementioned actual phase.

[0073] The Micro-LED element provided in this embodiment first determines the compensation phase, then the deflection phase, and finally combines the two phases to determine the actual phase of the metasurface 6. This allows the metasurface 6 to simultaneously collimate and deflect the light beam. By combining these two functions into a single metasurface 6, the metasurface 6 can replace the function of the DBR structure, thereby reducing or even eliminating the DBR structure and decreasing the thickness of the light-emitting side structure of the LED main body. This reduces element heat generation and improves light extraction efficiency while achieving beam deflection.

[0074] The specific structure of a Micro-LED element provided by this invention will be described in detail in the following embodiments.

[0075] Example 2

[0076] Please refer to Figures 2 to 14 , Figure 2 This is a front view schematic diagram of a specific Micro-LED element provided in an embodiment of the present invention; Figure 3 for Figure 2 A top-view structural diagram; Figure 4 This is a distribution diagram of the radius and phase of nanostructure units in the structure library; Figure 5 The wavefront phase diagram is shown for the case where the DBR period is 2 and the surface has not passed through the metasurface. Figure 6 The wavefront phase diagram is shown for the case where the DBR period is 3 and the surface has not passed through the metasurface. Figure 7 The wavefront phase diagram is shown for the case of passing through a metasurface when the DBR period is 2. Figure 8 The wavefront phase diagram is shown for the case of passing through a metasurface when the DBR period is 3. Figure 9 The image shows the far-field image of a metasurface with a conventional beam deflected by 30° when the DBR period is 2. Figure 10 The image shows the far-field image of a metasurface with a DBR period of 3 and a conventional beam deflected by 30°. Figure 11 The image is the far-field image of the metasurface in this embodiment when the DBR period is 2. Figure 12 The image is the far-field image of the metasurface in this embodiment when the DBR period is 3. Figure 13 The image is the far-field image of the metasurface in this embodiment when the DBR period is 4. Figure 14 This is a comparison of the efficiency of a conventional beam deflection metasurface and the metasurface in this embodiment when deflected by 30°.

[0077] Unlike the embodiments described above, this embodiment further defines the structure of the Micro-LED element based on the above embodiments. The remaining details have been described in detail in the above embodiments and will not be repeated here.

[0078] See Figure 2 In this embodiment, the LED main structure includes: a reflector layer 1, a p-type doped layer 2, a quantum well layer 3, and an n-type doped layer 4 arranged sequentially along the thickness direction; the metasurface 6 is located on the side of the n-type doped layer 4 away from the reflector layer 1.

[0079] The material of the aforementioned mirror layer 1 is typically a metal, specifically a metal with high reflectivity such as aluminum. The thickness of the mirror layer 1 is typically between 140 nm and 200 nm. Preferably, the material selected for the aforementioned mirror layer 1 is Al, and the thickness is 145 nm. The aforementioned p-type doped layer 2 can specifically be a p-type doped GaN layer, and the aforementioned n-type doped layer 4 can specifically be an n-type doped GaN layer. The active region of the quantum well layer 3 can specifically be a multiple quantum well (MQW) structure. The stacked structure of the aforementioned p-type doped layer 2, quantum well layer 3, and n-type doped layer 4 forms a resonant cavity. The projection of the mirror layer 1 in the thickness direction, i.e., the projection in the XOY plane, needs to coincide with the MQW structure of the active region of the n-type doped layer 4 and the quantum well layer 3, as well as the p-type doped layer 2.

[0080] The resonant cavity formed by stacking the p-type doped layer 2, quantum well layer 3, and n-type doped layer 4 has a square or rectangular projection on the XOY plane. That is, the projection of the resonant cavity on the horizontal plane is typically rectangular, with a side length usually not exceeding 2 μm, thus forming a Micro-LED element. In this embodiment, the center wavelength of the light emitted by the LED main structure is typically 450 nm, meaning the light emitted by the LED main structure is typically blue light. The corresponding total thickness L of the resonant cavity is based on the resonance condition of the Fabry-Perot interferometer, i.e., L = m * λ / n (where m is a positive integer and n is the refractive index). The refractive index of the active region MQW of the quantum well layer 3 is set to 2.50, meaning the real part of the refractive index of the quantum well layer 3 is 2.50. An electric dipole exists in the quantum well layer 3, and the emission center wavelength is 450 nm. Therefore, the total thickness L of the resonant cavity is 666.316 nm.

[0081] Specifically, in this embodiment, the thickness of the n-type doped layer 4 and the p-type doped layer 2 are both in the range of 100nm to 300nm; specifically, the thickness of the p-type doped layer 2 can be set to 120nm, the thickness of the quantum well layer 3 can be set to 120nm, and the thickness of the n-type doped layer 4 can be set to 426.316nm, so that the total thickness of the resonant cavity is 666.316nm.

[0082] In this embodiment, the LED main structure may further include a DBR layer 5, which is located on the surface of the n-type doped layer 4 away from the mirror layer 1, and the metasurface 6 is located on the surface of the DBR layer 5 away from the mirror layer 1. Specifically, the DBR layer 5 is disposed on the light-emitting side surface of the resonant cavity, that is, on the surface of the n-type doped layer 4 away from the quantum well layer 3. The DBR layer 5 typically includes a first dielectric layer 51 and a second dielectric layer 52 arranged in a periodic alternation pattern. The first dielectric layer 51 can be a SiO2 layer, and the second dielectric layer 52 can be a TiO2 layer. One layer of the first dielectric layer 51 and one layer of the second dielectric layer 52 constitutes one period. In this embodiment, the number of periods of the DBR layer 5 is typically no more than 5, meaning that a relatively thin DBR layer 5 can be provided. Alternatively, the DBR layer 5 can be omitted, as its function is also to collimate the beam. Theoretically, its function can be replaced by the metasurface 6, and omitting the DBR layer 5 allows the Micro-LED element to have the most efficient heat dissipation. However, in practice, due to limitations in structure or fabrication process, it is impossible to fabricate a metasurface 6 that meets the above requirements. Therefore, in this embodiment, a DBR layer 5 with a lower period number and thinner thickness can be set to perform a certain degree of light collimation function, thereby reducing the deviation range of the compensation phase corresponding to each region of the light-emitting side surface of the LED main structure, and thus reducing the range of actual phase values, so that the structure of each nanostructure unit 61 in the metasurface 6 can meet the fabrication requirements.

[0083] Specifically, in this embodiment, the thickness of the first dielectric layer 51SiO2 can be 48nm, and the thickness of the second dielectric layer 52TiO2 can be 81.81nm, to satisfy the formula n(refractive index)*H=λ / 4, where H is the thickness of each film layer, and λ is the center wavelength of the light emitted by the LED main structure.

[0084] See Figure 3 In this embodiment, the metasurface 6 can be specifically disposed on the surface of the DBR layer 5 away from the mirror layer 1. The material of the metasurface 6 can be TiO2, and the nanostructure unit 61 can be cylindrical. The period of the nanostructure unit 61 can be 250 nm, the height can be 800 nm, and the radius can be determined by the actual phase determined in the above embodiment or the actual phase distribution of the entire metasurface 6. In this embodiment, the metasurface 6 is composed of individual cylindrical nanostructure units 61, wherein the projection of the nanostructure unit 61 on the XOY plane, i.e., the horizontal plane, is circular. The nanostructure units 61 are periodically arranged above the n-type doped layer 4, covering the layer. In this embodiment, the metasurface 6 has nanostructure units 61 that simultaneously satisfy the target phase distribution of dual functions, so that the beam deflection and wavefront phase compensation are achieved. See [link to relevant documentation]. Figure 4All nanostructure units 61 satisfy the conditions of transmittance greater than 90% and phase coverage of 0 to 2π.

[0085] See Figure 5 , Figure 6 This is the wavefront phase diagram of the emitted light when the DBR layer has 2 and 3 periods respectively. The wavefront phase quality is measured by the annular variance, with a larger annular variance indicating a more chaotic wavefront phase. When the DBR layer has 2 periods, the annular variance is calculated to be 0.9190; when the DBR layer has 3 periods, the annular variance is calculated to be 0.8293. Figure 7 , Figure 8 The images show the wavefront phase diagrams of the light emitted from the metasurface 6 structure when the number of periods in the DBR layer 5 is 2 and 3, respectively. The calculated annular variances are 0.5526 and 0.4051, respectively. Both the wavefront phase images and the annular variances show that the wavefront phase quality is significantly improved after compensation by the metasurface 6 structure.

[0086] Figure 9 , Figure 10 The images show the far-field images after passing through a conventional beam deflection metasurface 6 with 2 and 3 periods in the DBR layer, respectively. It can be seen that when the DBR layer has 2 periods and the wavefront phase quality of the emitted light is poor, the conventional beam deflection metasurface cannot deflect the beam. When the DBR layer has 3 periods, the wavefront phase quality is improved, and beam deflection can be barely achieved, but the deflection efficiency is only 58.87%. Figure 11 , Figure 12 The images shown are far-field images of the Micro-LED element with the aforementioned metasurface 6 in this embodiment, with the DBR layer 5 having 2 and 3 periods respectively. The beam deflection effect of the metasurface 6 after phase compensation is significantly improved: when the DBR layer 5 has 2 periods, it can achieve a 30° beam deflection with a deflection efficiency of 63.20%; when the DBR layer 5 has 3 periods, the deflection efficiency reaches 97.58%.

[0087] Figure 13 The image shows the far-field image of the metasurface 6 in this embodiment when the DBR layer 5 has 4 periods. It can be seen that the deflected beam quality is good, with almost no background noise. Figure 14 The diagram shows a comparison of the efficiency of a Micro-LED element with a conventional beam deflection metasurface and a Micro-LED element with the metasurface provided in this embodiment when deflected by 30°. It shows that the Micro-LED element provided in this embodiment can not only achieve high-efficiency beam deflection, but also achieve the same beam deflection efficiency as the Micro-LED element with multiple DBRs when the conventional beam deflection metasurface Micro-LED element cannot deflect the beam.

[0088] In summary, the Micro-LED element provided by the embodiments of the present invention improves beam deflection efficiency compared with traditional beam deflection metasurfaces, especially in the case of large-angle deflection, and can obtain high-quality deflected beams. Even with a small logarithmic DBR, beam deflection function can be achieved and the heat generation problem of the device can be reduced. The present invention has broad application prospects in the fields of near-eye displays and medical bioimaging.

[0089] Example 3

[0090] This embodiment also provides an electronic device, including the Micro-LED element as described in the above embodiments. The specific structure of the Micro-LED element has been described in detail in the above embodiments and will not be repeated here. Other structures in the electronic device, such as the processor and power supply, can be set according to actual conditions and are not specifically limited here.

[0091] In this embodiment, since the electronic device includes the aforementioned Micro-LED element, the electronic device can have low heat generation and high light extraction efficiency.

[0092] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0093] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0094] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0095] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0096] The Micro-LED element and electronic device provided by this invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from the principles of this invention, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. A Micro-LED element, characterized in that, include: LED main structure; A metasurface located on the light-emitting side of the LED main structure; the metasurface comprises multiple nanostructure units distributed in an array, and the metasurface is prepared by the following method: Determine the phase information of each region on the light-emitting side surface of the LED main structure; Based on the reference phase, each of the phase information is compensated to determine the compensation phase of the corresponding nanostructure unit in each region; the phase information is combined with the corresponding compensation phase to make the wavefront phase of each region consistent. Determine the deflection phase corresponding to each nanostructure unit at the target deflection angle; The actual phase of each nanostructure unit is determined by superimposing the deflection phase and the compensation phase. The unit structure information of the corresponding nanostructure unit is determined based on the actual phase, so as to determine the structure of the metasurface based on the unit structure information.

2. The Micro-LED element according to claim 1, characterized in that, The determination of phase information for each region of the light-emitting side surface of the LED main structure includes: Obtain the overall phase information of the light-emitting side surface of the LED main structure; The overall phase information is sampled based on the period size of the nanostructure unit to determine the phase information of each region.

3. The Micro-LED element according to claim 2, characterized in that, Based on the reference phase, compensation is performed on each of the phase information to determine the compensation phase of the corresponding nanostructure unit in each region, including: Using the phase information of the center point of the light-emitting side surface of the LED main structure as the reference phase, compensation is performed on each of the phase information based on the reference phase to determine the compensation phase of the corresponding nanostructure unit in each region.

4. The Micro-LED element according to claim 1, characterized in that, Determining the deflection phase of each nanostructure unit at the target deflection angle includes: The deflection phase of each nanostructure unit at the target deflection angle was calculated based on the generalized Snell's law model.

5. The Micro-LED element according to claim 1, characterized in that, Determining the unit structure information of the corresponding nanostructure unit based on the actual phase, and determining the structure of the metasurface based on the unit structure information, includes: Based on the actual phase, select unit structure information corresponding to the actual phase from the structure library; the structure library includes the correspondence between the unit structure information and the actual phase; The structure of the metasurface is determined based on the unit structure information of the nanostructure units corresponding to each region.

6. The Micro-LED element according to claim 5, characterized in that, The metasurface design method also includes: Constructing multiple nanostructure units; The geometric parameters of each nanostructure unit are scanned to determine the corresponding unit structure information; The phase distribution of the nanostructure units at the target wavelength is obtained under the structural information of each unit, and the structure library is established.

7. The Micro-LED element according to claim 1, characterized in that, The main structure of the LED includes: A mirror layer, a p-type doped layer, a quantum well layer, and an n-type doped layer are sequentially arranged along the thickness direction; the metasurface is located on the side of the n-type doped layer away from the mirror layer.

8. The Micro-LED element according to claim 7, characterized in that, The LED main structure also includes a DBR layer, which is located on the surface of the n-type doped layer away from the mirror layer, and the metasurface is located on the surface of the DBR layer away from the mirror layer.

9. The Micro-LED element according to claim 8, characterized in that, The number of cycles in the DBR layer is no more than 5.

10. An electronic device, characterized in that, Includes the Micro-LED element as described in any one of claims 1 to 9.

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