CN114300594A - High-efficiency NanoLED structure suitable for near-to-eye display equipment and manufacturing method thereof - Google Patents
High-efficiency NanoLED structure suitable for near-to-eye display equipment and manufacturing method thereof Download PDFInfo
- Publication number
- CN114300594A CN114300594A CN202111618293.6A CN202111618293A CN114300594A CN 114300594 A CN114300594 A CN 114300594A CN 202111618293 A CN202111618293 A CN 202111618293A CN 114300594 A CN114300594 A CN 114300594A
- Authority
- CN
- China
- Prior art keywords
- film
- refractive index
- nano
- nanoled
- layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Landscapes
- Led Devices (AREA)
- Devices For Indicating Variable Information By Combining Individual Elements (AREA)
Abstract
The invention provides a high-efficiency NanoLED structure suitable for near-eye display equipment and a manufacturing method thereof. The light beams radiated by the multi-quantum well layer of the nano-pillar LED monomer are vertically emitted from the top section, and part of the light beams emitted in the non-vertical direction are polymerized through the gradient refractive index film covering the outer part of the side wall of the nano-pillar LED monomer, wherein the refractive index of the gradient refractive index film is increased along the radial direction of the axis, so that the polymerized light beams tend to be emitted in the vertical direction, the light emitting efficiency of the NanoLED light emitting array is further improved, and the crosstalk among pixels can be effectively reduced when the nano-pillar LED monomers with different diameters form the colorized NanoLED light emitting array.
Description
Technical Field
The invention belongs to the technical field of semiconductor light-emitting devices and nano LEDs, and particularly relates to a high-efficiency nano LED structure suitable for near-to-eye display equipment and a manufacturing method thereof.
Background
In recent years, with the advent of LED technology and micro integrated circuit technology, miniaturization and high-resolution projection display have become possible. With the continuous development of projection display technology and market demand, wearable micro projection light engines with large view field, high imaging quality and small volume are more and more emphasized, especially in the field of Near-eye display (NED) and wearable, which are developed today. Therefore, there is an increasing demand for LEDs as light sources of near-eye display devices, and particularly, high-light efficiency and low-power LEDs are favored. However, the current near-eye display devices based on various projection technologies such as LCOS, LCD, DMD or OLED still have many disadvantages such as low brightness of light source, high power consumption, large size, complex structure, etc., which greatly limits the development of the near-eye display devices in the consumer field.
With the advent of nanostructure light emitting diode (hereinafter referred to as nano led) display technology, the miniaturization of near-eye display devices has become possible. Firstly, the nano LED display technology is to miniaturize the traditional LED to form a micron-level or even submicron-level spacing LED array so as to achieve the ultrahigh density pixel resolution, each LED pixel in the nano LED array can self-illuminate, and the image display is further realized by accurately controlling the illumination intensity of each LED. Secondly, the nano LED can not only achieve the characteristics of high brightness, ultrahigh resolution, color saturation and high luminous efficiency, but also is not influenced by water vapor, oxygen or high temperature, so that the nano LED has obvious advantages in the aspects of stability, service life, working temperature and the like. Meanwhile, the NanoLED is used as a light source of the near-eye display equipment, so that the structure of the optical machine can be further simplified, the weight of the optical machine is reduced, and the near-eye display equipment has the experience of comfort and immersion.
However, the application of the nano led to near-eye display equipment still faces many challenges at present, and firstly, the preparation process of the nano led is complex and the precision requirement is high. Secondly, the multicolor LED array integrated on the single chip substrate has serious crosstalk among pixels, and the imaging quality of the colorized NanoLED light-emitting chip needs to be improved. Most importantly, the luminous efficiency is still to be improved due to the low dislocation density of the nanostructure of the nanoleds.
In order to realize the application of the nano light emitting diode with high luminous efficiency and low power consumption to the near-eye display device, the structure of the nano light emitting diode needs to be optimized and improved in the aspects of luminous efficiency and reduction of crosstalk between pixels.
Disclosure of Invention
In view of the above, in order to fill up the blank in the prior art, the present invention aims to provide a high efficiency nano LED structure suitable for a near-eye display device and a manufacturing method thereof, so as to improve the light emitting efficiency of a nano LED light emitting array, and simultaneously effectively reduce crosstalk between nano-pillar LED array pixels, so that the near-eye display device has a low power, high efficiency light source and a higher quality image.
The provided NanoLED structure consists of a NanoLED light-emitting array and a gradient refractive index film, wherein the NanoLED light-emitting array consists of a plurality of InGaN/GaN nanorod LED monomers which are vertically grown on a substrate and have the same or different diameters, and each nanorod LED monomer is a display pixel or a sub-pixel of the NanoLED light-emitting array. The light beams radiated by the multi-quantum well layer of the nano-pillar LED monomer are vertically emitted from the top section, and part of the light beams emitted in the non-vertical direction are polymerized through the gradient refractive index film covering the outer part of the side wall of the nano-pillar LED monomer, wherein the refractive index of the gradient refractive index film is increased along the radial direction of the axis, so that the polymerized light beams tend to be emitted in the vertical direction, the light emitting efficiency of the NanoLED light emitting array is further improved, and the crosstalk among pixels can be effectively reduced when the nano-pillar LED monomers with different diameters form the colorized NanoLED light emitting array. The inventive NanoLED structure as an optical element can provide a near-eye display device with higher luminous efficiency, lower power light source and higher quality image.
Based on the research and design, the invention specifically adopts the following technical scheme:
a high efficiency NanoLED structure suitable for near-to-eye display devices, characterized in that: the nano LED light emitting array is composed of a plurality of InGaN/GaN nano column LEDs integrated on a substrate, and each nano column LED is independently driven and emits light beams; the gradient refractive index film covers the outer part of the side wall of each nano-pillar monomer and is used for converging emergent light of the nano-pillar LED in the non-vertical direction and emitting the emergent light along the vertical direction.
Furthermore, the nano-pillar monomer grows on the substrate, the diameter is 50nm-600nm, the thickness of the gradient refractive index film is 50nm-600nm, the diameter after the gradient refractive index film is coated is 100nm-800nm, the center distance between two adjacent pixels is 500nm-900nm, and the gap distance between the outermost layer films of the gradient refractive index film of the adjacent InGaN/GaN nano-pillar LED monomer is 100nm-200 nm.
Further, the structure of the nano-pillar monomer sequentially comprises from the substrate to the top: 25nm-50nm GaN buffer layer, 30 μm-60 μm n-type GaN layer, 80 μm-120 μm multi-period multi-quantum well layer, and 200nm-500nm p-type GaN layer; the n-type GaN layers of the nano-pillar LEDs are connected with each other, and the tops of the p-type GaN layers are connected with each other through the ITO transparent film.
The InGaN/GaN nanorod LED material is generally required to have uniform material density distribution so as to form a stably emitted light beam. The InGaN/GaN nanorod LED monomer multi-quantum well layer spontaneously radiates light beams propagating in all directions, a part of the light beams radiated by the multi-quantum well layer are emitted from the top cross section of the columnar structure, the emergent light direction is perpendicular to the substrate, each nanorod LED monomer is equivalent to a display pixel or a sub-pixel, the other part of the light beams are emitted from the side face of the nanorod, and the part of the light beams are incident and regulated by the gradient refractive index film on the periphery of the nanorod.
Furthermore, the nano-column monomers are uniformly arranged on the substrate to form a nano-column array, and the wavelength of a light beam emitted by the nano-column monomers is in inverse proportion to the diameter of the nano-column monomers; the nano-pillar array is composed of nano-pillar monomers with the same or different diameters, and emits light beams with the same or different wavelengths in the visible light range to form a monochromatic or colorized NanoLED light-emitting array.
Further, the structure of the gradient refractive index film is SiO prepared by a sol-gel process2-metal oxide glass, each layer of thin film having a graded refractive index; the outermost layer is attached with an isolation layer formed by a resin film added with a foaming agent, and a bubble structure is arranged in the isolation layer and used for reflecting and transmitting beams of the gradient refractive index film layer so as to prevent crosstalk between nano-pillar pixels.
Furthermore, each layer of the film of the gradient refractive index film has metal oxide with concentration gradient distribution, and the concentration of the metal oxide of each layer of the film is increased from the axial center to the radial direction, so that the film structure forms refractive index distribution which is increased along the axial center to the radial direction.
Changing the light radiation direction of the InGaN/GaN nanorod monomer multi-quantum well layer by the gradient refractive index film, and generating light beams which tend to be vertical to the substrate direction for emitting; and the maximum deflection angle of the light beam generated by the InGaN/GaN nano-column monomer multi-quantum well layer photon radiation in the direction not vertical to the substrate is at most 90 degrees.
Further, the refractive index of the first film layer of the gradient refractive index film towards the LED side is defined as N1, the refractive index of the second film layer is defined as N2 and the refractive index of the outermost film layer of … … is defined as Nn; wherein the refractive index change of each film layer of the gradient refractive index film is expressed by the following formula: n (r) = N1[ (1-A/2) r ^2], wherein N (r) in the formula represents the refractive index of different film layers, A represents the refractive index distribution constant of the gradient refractive index film, r represents the diameter of the gradient refractive index film, and the refractive index distribution constant A is an experimental value and is related to the maximum angle of the light beam to be polymerized by the gradient refractive index film.
And, a method for fabricating a high efficiency NanoLED structure suitable for near-to-eye display devices, comprising:
step S1: growing a plurality of vertical InGaN/GaN nanorod monomers on a substrate to form an InGaN/GaN nanorod array;
step S2: inverting the nano-column array, and immersing in SiO2Vertical pulling in metal oxide sol, controlling the pulling speed to form sol film on the side wall of nano column monomer, and drying in air to form SiO2After the metal oxide gel film is coated, soaking the gel film in nitric acid to control the content of the metal oxide in the gel film and carrying out surface treatment, washing the gel film with alcohol and deionized water, and drying the gel film to obtain a layer of glass film;
step S3: repeating step S2 until a multilayer thin film structure is formed; and inversely immersing the substrate coated with the multilayer glass film into the polyester resin isolation layer sol, vertically lifting, and drying in air to form the isolation layer on the outermost layer of the gradient refractive index film.
Further, the SiO2The metal oxide sol is a mixed solvent comprising ethyl orthosilicate, ethanol, nitric acid and metal oxide acid esters, and is prepared by adding deionized water and dimethylformamide after stirring; the polyester resin isolation layer sol comprises a mixed solvent of neopentyl glycol, trihydroxyethyl ethane and adipic acid, and a foaming agent is added after stirring to form a micro-bubble structure in the sol.
Further, in step S1, the molecular beam of elements including Ga and N is jetted through the jet furnace in a mask array preset on the substrate, the molecular beam epitaxially grows on the substrate to form an arrayed InGaN/GaN semiconductor mixed crystal, and after etching and cleaning the mask and drying, an InGaN/GaN nano-pillar array is formed on the substrate.
Further, in step S3, the same pulling speed is used each time step S2 is repeated to form a multilayer thin film having a uniform thickness; the gradient change of the refractive index is formed by controlling different time of each film formation in the nitric acid soaking.
The near-to-eye display device obtained according to the design can comprise optical components such as a NanoLED light source, a coupling waveguide and a glass substrate, and when the NanoLED light source is a monochromatic light emitting array formed by InGaN/GaN nano-pillars with the same diameter, the gradient refractive index film can efficiently condense emergent light in a non-vertical direction and emit the light along the vertical direction so as to improve the light emitting efficiency of the NanoLED light source; when the NanoLED light source is a colorized light-emitting array formed by InGaN/GaN nano-columns with different diameters, the gradient refractive index film can effectively reduce crosstalk between pixels while improving the light efficiency of the light source, and the imaging quality of the light source is improved. And the NanoLED light source is transmitted in the glass substrate through the coupling waveguide and reaches human eyes, so that the near-eye display device has a light source with lower power consumption and higher light effect and a higher-quality image.
Compared with the prior art, the light emitting device and the optimization scheme thereof have the advantages that the gradient refractive index film is coated on the side wall of each InGaN/GaN nanorod LED monomer, light beams of the non-vertical substrate radiated by the multi-quantum well layer are polymerized, and emergent light tending to the vertical direction is generated, so that the light emitting efficiency of the NanoLED light emitting array is improved, and meanwhile crosstalk among pixels is effectively reduced. When the NanoLED structure is used as a light source for a near-eye display device, the light source with lower power consumption and higher light effect and higher-quality images can be provided for the near-eye display device.
Drawings
The invention is described in further detail below with reference to the following figures and detailed description:
the accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
fig. 1 is a side view of a high efficiency NanoLED structure suitable for use in a near-eye display device according to an embodiment of the present invention.
Fig. 2 is a top view of a high efficiency NanoLED structure suitable for use in a near-eye display device according to an embodiment of the present invention.
Fig. 3 is a schematic structural diagram corresponding to a third modified embodiment of the example of the present invention.
Fig. 4 is a schematic structural diagram corresponding to a fourth modified embodiment of the example of the present invention.
Fig. 5 is a schematic structural diagram corresponding to a fifth modified embodiment of the example of the present invention.
Detailed Description
In order to make the features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail as follows:
the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The components generally described and illustrated in the figures herein may be designed in various combinations and configurations. Thus, the following detailed description of selected embodiments of the invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the invention without making any creative effort, fall within the protection scope of the invention.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
In consideration of the NanoLED display technology, the traditional LEDs are miniaturized to form a micron-scale or even submicron-scale distance LED array so as to achieve ultrahigh-density pixel resolution, each LED pixel in the NanoLED array can self-illuminate, and image display is further achieved by accurately controlling the illumination intensity of each LED. The light source of the NanoLED light-emitting array is a light beam emitted by a InGaN/GaN nanorod LED multi-quantum well layer along a vertical substrate, and the light beam emitted by the LED multi-quantum well layer in other directions is scattered and transmitted in the nanorod array to be consumed, so that the NanoLED has the phenomena of low light-emitting efficiency, high power and poor heat dissipation when being applied to near-eye display equipment, and serious inter-pixel crosstalk can occur when a full-color NanoLED light-emitting array formed by the nanorod LEDs with different diameters is prepared on the substrate, and the imaging quality is influenced.
In order to enable the NanoLED light-emitting array to have higher light-emitting efficiency and better imaging quality when being applied to near-eye display equipment as an optical element, the embodiment of the invention provides an efficient NanoLED structure which can converge light beams radiated by LED multiple quantum well layers in a non-vertical direction and generate light beams which are emitted in a direction which is inclined to the vertical direction. Referring to fig. 1 in particular, a side cross-sectional view thereof can be seen that the light-emitting diode comprises a substrate 100, an InGaN/GaN nanorod LED array, and a gradient index film 300 coated on the sidewall of an InGaN/GaN nanorod LED single body 200. The InGaN/GaN nanorod LED array grows on a substrate 100 and comprises a plurality of InGaN/GaN nanorod LED monomers 200 with the same diameter, wherein the InGaN/GaN nanorod LED monomers 200 form a GaN buffer layer 210 with the diameter of 25nm-50nm, an n-type GaN layer 220 with the diameter of 30 microns-60 microns, an 8-period multi-quantum well layer 230 with the diameter of 80 microns-120 microns and a p-type GaN layer 240 with the diameter of 200nm-500nm in sequence from the substrate to the upper direction, and the n-type GaN layers 220 are connected with one another through the GaN buffer layer 210.
More specifically, the graded-index film 300 serves to condense the non-vertical outgoing light beams radiated from the multiple quantum well layer 230 of the InGaN/GaN nanorod LED cell 200 and generate outgoing light tending to the vertical direction. It can be understood that, in the present invention, since the light beams radiated from the multiple quantum well layer 230 in the non-vertical direction are polymerized by the gradient refractive index film 300, the light beams emitted from the nano led in the vertical direction are increased, the light emitting efficiency of the nano led is improved, the light beams scattered and propagated in the nano-pillar array are reduced, the heat dissipation of the nano led array is facilitated, and meanwhile, the inter-pixel crosstalk of the nano led light emitting array can be avoided, and the imaging quality is improved.
In addition, referring to fig. 2, in an embodiment of the invention, the diameter w of the InGaN/GaN nanorod LED single body 200 is 200nm, and the interval d between the light emitting pixels is 800 nm. In addition, the thickness of the nanorod LED monomer I coated with the gradient refractive index film is 410nm, the thickness of the gradient refractive index 300 coated outside the side wall of the InGaN/GaN nanorod LED monomer 200 is 100nm, and the distance h between the InGaN/GaN nanorod LED monomers coated with the gradient refractive index film is 400 nm. Wherein the gradient index film 300 is SiO with the same thickness of 10 layers2-TiO2Film composition with 10 layers of SiO2-TiO2The Ti element concentration of the film increases from the axial center to form gradient change.
It is worth noting that in the present inventionIn the illustrated embodiment, to form 10 layers of SiO with the same thickness2The film needs to control the concentration and viscosity of sol and the dipping and lifting speed of the LED array substrate in the coating process flow of the high-efficiency NanoLED manufacturing method. Preferably, SiO in the examples of the present invention2-TiO2The sol is prepared by mixing and stirring 0.1mol of ethyl orthosilicate, 0.6mol of ethanol, 0.32mol of 70% nitric acid and 0.05mol of tetrabutyl titanate, and then adding 0.3mol of deionized water, 1mL of dimethylformamide and 0.4mol of dimethylformamide, wherein the viscosity index at room temperature is 165; the outermost polyester resin isolation layer sol is prepared from a mixed solvent of 0.5mol of neopentyl glycol, 0.25mol of trimethylolethane and 0.5mol of adipic acid, 0.8g of foaming agent is added after stirring, so that a micro-bubble structure is formed in the sol, and the average pore diameter of the micro-bubble structure is 2 nm. In addition, the speed is kept at 1.0mm/s in the process of reversely immersing the LED array substrate with the nano-pillars into the sol and vertically pulling the substrate for 10 times, and a multilayer film with uniform thickness is obtained after cleaning and drying treatment, wherein the thickness of the single-layer film is about 10 nm. And then, reversely immersing the substrate coated with the multilayer glass film into the polyester resin isolation layer sol, vertically pulling at the same speed, and drying in air to form a 10 nm-thick isolation layer on the outermost layer of the gradient refractive index film. The total thickness of the finally formed gradient refractive index film 300 is about 100 nm.
It is noted that, in the above-mentioned embodiments of the present invention, in order to form 10 layers of SiO with Ti element concentration increased from the axial center in the radial direction2The film needs to be immersed in nitric acid for a controlled bath time in the coating process flow of the high-efficiency NanoLED manufacturing method. Preferably, the nitric acid specification of the present invention is 0.08mol, 70%, after SiO is completed2-TiO2After the preparation of the gel film, coating SiO2-TiO2The LED array substrate of the gel film is immersed in nitric acid for 10 times, the first immersion time is 30s, and the subsequent immersion times are sequentially increased by 10s until 10 layers of SiO are formed2-TiO2The gel film is completely immersed in the bath. Wherein, after each dipping bath, the dipping bath is washed by alcohol and deionized water and dried. Specifically, the refractive index of the first layer of the graded-index film 300 of the LED is 1.45, and the refractive indices of the outer layers are sequentially increased by 0.03.
It is noted that in the above-mentioned embodiments of the present invention, 10 layers of SiO with Ti element concentration gradient were prepared according to the manufacturing method of an efficient NanoLED structure of the present invention2-TiO2Film to form 10 layers of SiO2-TiO2A gradient in the refractive index of the film. The gradient refractive index film 300 of the embodiment can efficiently polymerize the multi-quantum well layer 230 of the nanorod LED single body 200 to radiate light beams in a non-vertical direction, thereby improving the light extraction efficiency. Through software simulation, compared with a NanoLED with a common structure without the integrated gradient refractive index film 300, the light emitting efficiency of the NanoLED light emitting array with the NanoLED structure in the embodiment of the invention is improved by about 55%, and the power consumption is reduced by about 23%.
Further, in the first modification of the above-described embodiment of the present invention, the gradient refractive index film 300 has SiO with 10 layers of different thicknesses2-TiO2Thin film, 10 layers of SiO2-TiO2The thickness of the film increases from the axial center in the radial direction, and Ti element concentration gradient changes to form 10 layers of SiO by dipping in nitric acid for the same time to form each film layer2-TiO2A gradient in the refractive index of the film. It can be understood that in the modification of this embodiment, the sol concentration, viscosity and dipping speed of the LED array substrate need to be controlled in the coating process flow of the method for manufacturing a high-efficiency NanoLED according to the present invention. Specifically, the modified form SiO of the present embodiment2-TiO2The sol is prepared by mixing and stirring 0.1mol of ethyl orthosilicate, 0.6mol of ethanol, 0.04mol of 70 percent nitric acid and 0.05mol of tetrabutyl titanate, and then adding 0.3mol of deionized water, 1mL of dimethylformamide and 0.4mol of dimethylformamide, wherein the viscosity index at room temperature is 165; the outermost polyester resin isolation layer sol is prepared from a mixed solvent of 0.5mol of neopentyl glycol, 0.25mol of trimethylolethane and 0.5mol of adipic acid, 0.8g of foaming agent is added after stirring, so that a micro-bubble structure is formed in the sol, and the average pore diameter of the micro-bubble structure is 2 nm. However, in the process of reversely immersing the LED array substrate on which the nano-pillars are grown into the sol and vertically pulling, the first pulling speed is 5mm/s, the subsequent pulling speed is sequentially increased by 1mm/, the thickness of the first layer film close to the LED after cleaning and drying treatment is about 6nm, and the thickness of the outer layer film is sequentially increased by 2 nm.And then, reversely immersing the substrate coated with the multilayer glass film into the polyester resin isolation layer sol, vertically pulling at the same speed, and drying in air to form a 10 nm-thick isolation layer on the outermost layer of the gradient refractive index film.
In addition, in the first modification of the above embodiment of the present invention, it is necessary to control the dipping of the gel film in nitric acid for the same time in the plating process flow of the high efficiency NanoLED manufacturing method of the present invention. Specifically, the specification of the nitric acid is 0.04mol, 70 percent, and SiO is finished2-TiO2After the preparation of the gel film, coating SiO2-TiO2The LED array substrate of the gel film is immersed in nitric acid for 10 times, and the time of each immersion bath is 60s till 10 layers of SiO2-TiO2The gel film is completely immersed in the bath. Wherein, after each dipping bath, the dipping bath is washed by alcohol and deionized water and dried.
It is noted that in a first variation of the above-described embodiment of the present invention, the thickness of the 10 layers prepared according to the method of the present invention for fabricating an efficient NanoLED structure is increased radially from the axis by SiO2-TiO2Film, 10 layers of SiO by controlling the immersion bath of the gel film in nitric acid to be the same phase2-TiO2The Ti element concentration gradient is formed to form 10 layers of SiO2-TiO2A gradient in the refractive index of the film. Preferably, the same effects as in the above embodiment are produced by changing the parameters of the sol, the immersion time in acid, and the like.
It is noted that, in the above-mentioned embodiment of the present invention and the first modification of the above-mentioned embodiment, the graded-index film 300 is SiO2-TiO2A multilayer glass film structure prepared from the gel film. It is understood that in order to obtain a more active and stable gel material, the second variant of the above embodiment is proposed, and it is necessary to use SiO in the manufacturing method of a high-efficiency NanoLED structure according to the present invention2The metal oxide sol selects Bi, Cd and other metal elements to form the gradient refractive index. In particular, the use of Bi in the method of manufacturing a high efficiency NanoLED structure in the present invention2O3-BiO(NO3)·H2Preparing SiO by using mixed solvent of O, ethyl orthosilicate, ethanol, tetrabutyl titanate and nitric acid2-Bi2O3Sol and forming a plurality of layers of SiO with gradient concentration of Bi element by the same steps of film deposition as in the previous embodiment2-Bi2O3Thin film structure, and multilayer SiO2-Bi2O3The thin film structure has a gradient refractive index change with the same effect as the above embodiment.
Further, in a second variation of the above embodiment, Cd is used in the method for manufacturing a high-efficiency NanoLED structure according to the present invention3(OC2H5)2As a sol precursor, a mixed solvent of ethyl orthosilicate, ethanol, tetrabutyl titanate and nitric acid is added, and a plurality of layers of CdO-SiO with Cd element concentration gradient are formed by the same film deposition steps as the above embodiment2Thin film structure, and multilayer CdO-SiO2The thin film structure has a gradient refractive index change with the same effect as the above embodiment.
Referring to fig. 3, a third variation of the high efficiency NanoLED structure suitable for a near-eye display device, in order to further improve the light extraction efficiency of the high efficiency NanoLED structure of the present invention, the present variation proposes an improved NanoLED structure in which an Ag film 400 is coated on a GaN buffer layer 210 of an InGaN/GaN nanorod LED cell 200.
The thickness of the Ag film 400 is 60 μm, the non-vertical direction light beam generated by photon radiation of the InGaN/GaN nanorod monomer multi-quantum well layer is reflected by a partial light beam in a negative angle along the vertical direction, and further, the light beam reflected by the Ag film 400 is in a positive angle along the vertical direction, continues to be transmitted between the gradient refractive index films 300, and is polymerized and emitted along the vertical direction.
In addition, in this third modified embodiment, in order to prevent the Ag film 400 from causing a short circuit, a transparent insulating film layer needs to be coated on the GaN buffer layer 210 of the nanorod LED in advance.
It is noted that, in this third modified embodiment, the Ag film 400 facilitates the heat conduction of the InGaN/GaN nanorod LED cell 200 to achieve the heat dissipation effect. And through software simulation, the light emitting efficiency of the NanoLED in the deformed embodiment is improved by about 40% compared with that of the structure before improvement. This deformation implementation mode not only promotes on luminous efficiency by a wide margin, but also has better radiating effect, more can satisfy near-to-eye display device low-power consumption, efficient demand.
Referring to fig. 4, a fourth variant embodiment of the high-efficiency NanoLED structure suitable for a near-eye display device, in order to better apply the high-efficiency NanoLED structure of the present invention to a near-eye display device and realize full-color pixels with uniform color, the present variant embodiment proposes an improved colorized NanoLED structure: the quantum dot film 500 is coated on the top of the InGaN/GaN nanorod LED single body 200 and the gradient refractive index film 300, and the InGaN/GaN nanorod LED single body 200 partially coated with the quantum dot film 500 and the uncoated single body are combined into a full-color pixel.
Specifically, the quantum dot film 500 of the present modified embodiment is a resin material in which quantum dots are dispersed, and is prepared from a film material in which quantum dots are dispersed and encapsulated in two barrier layers. The quantum dot film 500 can emit green light and red light under the excitation of the blue InGaN/GaN nanorod LED200, and is mixed with blue light emitted by the InGaN/GaN nanorod LED single body 200 partially not coated with the quantum dot film to form a full-color pixel.
Preferably, the thickness of the quantum dot film 500 of the fourth modified embodiment described above is 100nm, and is disposed on top of the InGaN/GaN nanorod LED cells 200 and the graded-index film 300 through a coating process.
More specifically, the InGaN/GaN nanorod LED cell 200 partially coated with the quantum dot film 500 in the fourth modified embodiment described above forms a green pixel and a red pixel, and forms one full-color pixel in combination with the remaining uncoated single LEDs emitting blue light. Through software simulation, the improved colorized nano led structure of the fourth modified embodiment can emit relatively uniform full-color light beams, and realize full-color pixels with uniform colors.
Referring to fig. 5, in order to apply a full-color nano LED light emitting array composed of nano-pillar LEDs with different diameters to a near-eye display device and further reduce crosstalk between nano-pillar LED pixels, and achieve a better imaging effect, the fifth modified embodiment provides an improved colorized nano LED light emitting array structure: the color NanoLED light emitting array is composed of InGaN/GaN nanopillar LED single bodies 200 with different diameters grown on a substrate 100 and a gradient refractive index 300 outside the sidewall of the InGaN/GaN nanopillar LED single body 200, wherein each 4 InGaN/GaN nanopillar LED single bodies constitute one color light emitting pixel 205 of the color NanoLED light emitting array.
Specifically, one color light-emitting pixel 205 of the present modified embodiment is composed of one blue InGaN/GaN nanopillar LED single body 201 with a diameter of 300nm, two identical green InGaN/GaN nanopillar LED single bodies 202 and 204 with a diameter of 240nm, and one red InGaN/GaN nanopillar LED single body 203 with a diameter of 130 nm.
It should be noted that, in the color light emitting pixel 205 according to this modified embodiment, in order to converge the light beams emitted from the non-vertical substrate by the multi-quantum well layer of each InGaN/GaN nanorod LED unit and generate the emergent light tending to the vertical direction, and simultaneously, to effectively reduce the crosstalk between each nanorod LED unit and other color light emitting pixels, the thicknesses of the gradient refractive index films covering the outer portions of the sidewalls of each InGaN/GaN nanorod LED unit should be different.
Specifically, in the present embodiment, the thickness of the gradient index film covering the sidewall of the InGaN/GaN nanorod LED cell 201 is 300nm, the thickness of the gradient index film covering the sidewall of the InGaN/GaN nanorod LED cells 202 and 204 is 260nm, and the thickness of the gradient index film covering the sidewall of the InGaN/GaN nanorod LED cell 203 is 220 nm.
Through software simulation, compared with the traditional color nano LED light emitting array, the full-color nano LED light emitting array of the fifth modified embodiment has more uniform light spots, obviously improved color difference and effectively reduced crosstalk between pixels. In addition, the full-color nano LED light emitting array structure of the embodiment can simplify the optical structure of the near-eye display equipment, and is beneficial to promoting the development of miniaturized and high-imaging-quality near-eye display equipment.
The above is only a preferred embodiment of the invention, and the invention is not limited to the above embodiment, and the invention shall fall within the protection scope of the invention as long as the technical effects of the invention are achieved by the same means.
The foregoing is directed to preferred embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope of the technical solution of the present invention.
The present invention is not limited to the above preferred embodiments, and all other types of high efficiency NanoLED structures suitable for near-eye display devices and methods for making the same can be obtained from the teaching of the present invention.
Claims (10)
1. A high efficiency NanoLED structure suitable for near-to-eye display devices, characterized in that: the nano LED light emitting array is composed of a plurality of InGaN/GaN nano column LEDs integrated on a substrate, and each nano column LED is independently driven and emits light beams; the gradient refractive index film covers the outer part of the side wall of each nano-pillar monomer and is used for converging emergent light of the nano-pillar LED in the non-vertical direction and emitting the emergent light along the vertical direction.
2. A high efficiency NanoLED structure suitable for use in a near-eye display device as claimed in claim 1 wherein: the nano-pillar monomer grows on the substrate, the diameter is 50nm-600nm, the diameter after the nano-pillar monomer is coated with the gradient refractive index film is 100nm-800nm, the center distance between two adjacent pixels is 500nm-900nm, and the gap distance between the outermost layer films of the gradient refractive index films of the adjacent InGaN/GaN nano-pillar LED monomer is 100nm-200 nm.
3. A high efficiency NanoLED structure suitable for use in a near-eye display device as claimed in claim 1 wherein: the structure of the nano-column monomer is sequentially from the substrate to the top: 25nm-50nm GaN buffer layer, 30 μm-60 μm n-type GaN layer, 80 μm-120 μm multi-period multi-quantum well layer, and 200nm-500nm p-type GaN layer; the n-type GaN layers of the nano-pillar LEDs are connected with each other, and the tops of the p-type GaN layers are connected with each other through the ITO transparent film.
4. A high efficiency NanoLED structure suitable for use in a near-eye display device as claimed in claim 1 wherein: the gradient refractive index film is made of SiO prepared by a sol-gel process2-metal oxide glass, each layer of thin film having a graded refractive index; the outermost layer is attached with an isolation layer formed by a resin film added with a foaming agent, and a bubble structure is arranged in the isolation layer and used for reflecting and transmitting beams of the gradient refractive index film layer so as to prevent crosstalk between nano-pillar pixels.
5. The high efficiency NanoLED structure suitable for use in a near-eye display device according to claim 4 wherein: each layer of film of the gradient refractive index film is provided with metal oxide with concentration gradient distribution, and the concentration of the metal oxide of each layer of film is increased from the axial center in the radial direction, so that the film structure forms refractive index distribution which is increased along the axial center in the radial direction.
6. The high efficiency NanoLED structure suitable for use in a near-eye display device according to claim 4 wherein: defining the refractive index of the first film layer of the gradient refractive index film towards the LED side as N1, the refractive index of the second film layer is defined as N2 outwards along the axis of the nano-pillar LED, and the refractive index of the … … outermost film layer is defined as Nn; wherein the refractive index change of each film layer of the gradient refractive index film is expressed by the following formula: n (r) = N1[ (1-A/2) r ^2], wherein N (r) in the formula represents the refractive index of different film layers, A represents the refractive index distribution constant of the gradient refractive index film, r represents the diameter of the gradient refractive index film, and the refractive index distribution constant A is an experimental value and is related to the maximum angle of the light beam to be polymerized by the gradient refractive index film.
7. A high efficiency NanoLED structure suitable for use in a near-eye display device as claimed in claim 1 wherein: the nano-column monomers are uniformly arranged on the substrate to form a nano-column array, and the wavelength of a light beam emitted by the nano-column monomers is in inverse proportion to the diameter of the nano-column monomers; the nano-pillar array is composed of nano-pillar monomers with the same or different diameters, and emits light beams with the same or different wavelengths in the visible light range to form a monochromatic or colorized NanoLED light-emitting array.
8. A manufacturing method of a high-efficiency NanoLED structure suitable for near-eye display equipment is characterized by comprising the following steps of:
step S1: growing a plurality of vertical InGaN/GaN nanorod monomers on a substrate to form an InGaN/GaN nanorod array;
step S2: inverting the nano-column array, and immersing in SiO2Vertical pulling in metal oxide sol, controlling the pulling speed to form sol film on the side wall of nano column monomer, and drying in air to form SiO2After the metal oxide gel film is coated, soaking the gel film in nitric acid to control the content of the metal oxide in the gel film and carrying out surface treatment, washing the gel film with alcohol and deionized water, and drying the gel film to obtain a layer of glass film;
step S3: repeating step S2 until a multilayer thin film structure is formed; and inversely immersing the substrate coated with the multilayer glass film into the polyester resin isolation layer sol, vertically lifting, and drying in air to form the isolation layer on the outermost layer of the gradient refractive index film.
9. The method of claim 8, wherein the method comprises: the SiO2The metal oxide sol is a mixed solvent comprising ethyl orthosilicate, ethanol, nitric acid and metal oxide acid esters, and is prepared by adding deionized water and dimethylformamide after stirring; the polyester resin isolation layer sol comprises a mixed solvent of neopentyl glycol, trihydroxyethyl ethane and adipic acid, and a foaming agent is added after stirring to form a micro-bubble structure in the sol.
10. The method of claim 8, wherein the method comprises: in step S1, spraying an elemental molecular beam including Ga and N through a spray furnace in a mask array preset on a substrate, wherein the molecular beam epitaxially grows on the substrate to form an arrayed InGaN/GaN semiconductor mixed crystal, and after etching to clean the mask and drying, an InGaN/GaN nanorod array is formed on a substrate;
in step S3, the same pulling speed is used each time step S2 is repeated to form a multilayer film with uniform thickness; the gradient change of the refractive index is formed by controlling different time of each film formation in the nitric acid soaking.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111618293.6A CN114300594B (en) | 2021-12-28 | 2021-12-28 | High-efficiency NanoLED structure suitable for near-eye display equipment and manufacturing method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111618293.6A CN114300594B (en) | 2021-12-28 | 2021-12-28 | High-efficiency NanoLED structure suitable for near-eye display equipment and manufacturing method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114300594A true CN114300594A (en) | 2022-04-08 |
| CN114300594B CN114300594B (en) | 2023-09-29 |
Family
ID=80970278
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111618293.6A Active CN114300594B (en) | 2021-12-28 | 2021-12-28 | High-efficiency NanoLED structure suitable for near-eye display equipment and manufacturing method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114300594B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115047571A (en) * | 2022-06-27 | 2022-09-13 | 中国科学院半导体研究所 | Film coating structure of optical detector chip |
| CN116504888A (en) * | 2023-04-27 | 2023-07-28 | 江苏第三代半导体研究院有限公司 | Epitaxial wafer and preparation method and application thereof |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102402907A (en) * | 2011-12-05 | 2012-04-04 | 广东威创视讯科技股份有限公司 | Device for improving display effect of light-emitting diode (LED) display screen |
| CN106384763A (en) * | 2016-10-31 | 2017-02-08 | 华南理工大学 | Non-polar InGaN/GaN multi-quantum-well nano-pillar and preparation method thereof |
| CN107731972A (en) * | 2017-10-24 | 2018-02-23 | 江门市奥伦德光电有限公司 | A kind of strip array nano luminescent diode and preparation method thereof |
| CN109841711A (en) * | 2019-02-01 | 2019-06-04 | 中国科学院半导体研究所 | White light LEDs and preparation method thereof based on non-radiative resonance energy transfer mechanism |
| CN110311023A (en) * | 2019-06-24 | 2019-10-08 | 南京大学 | Utilize surface phasmon enhancing LED light communication device and preparation method thereof |
| WO2019237618A1 (en) * | 2018-06-15 | 2019-12-19 | 华南理工大学 | Manufacturing method for hydrophobic/light-trapping fly-eye lens array having micro-nano two-stage structure and application thereof |
| CN112599553A (en) * | 2020-12-15 | 2021-04-02 | 天津赛米卡尔科技有限公司 | Novel Micro-LED display array capable of reducing optical crosstalk and preparation method thereof |
| CN214898481U (en) * | 2021-06-23 | 2021-11-26 | 南方科技大学 | Micro-LED display device for reducing pixel optical crosstalk |
-
2021
- 2021-12-28 CN CN202111618293.6A patent/CN114300594B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102402907A (en) * | 2011-12-05 | 2012-04-04 | 广东威创视讯科技股份有限公司 | Device for improving display effect of light-emitting diode (LED) display screen |
| CN106384763A (en) * | 2016-10-31 | 2017-02-08 | 华南理工大学 | Non-polar InGaN/GaN multi-quantum-well nano-pillar and preparation method thereof |
| CN107731972A (en) * | 2017-10-24 | 2018-02-23 | 江门市奥伦德光电有限公司 | A kind of strip array nano luminescent diode and preparation method thereof |
| WO2019237618A1 (en) * | 2018-06-15 | 2019-12-19 | 华南理工大学 | Manufacturing method for hydrophobic/light-trapping fly-eye lens array having micro-nano two-stage structure and application thereof |
| CN109841711A (en) * | 2019-02-01 | 2019-06-04 | 中国科学院半导体研究所 | White light LEDs and preparation method thereof based on non-radiative resonance energy transfer mechanism |
| CN110311023A (en) * | 2019-06-24 | 2019-10-08 | 南京大学 | Utilize surface phasmon enhancing LED light communication device and preparation method thereof |
| CN112599553A (en) * | 2020-12-15 | 2021-04-02 | 天津赛米卡尔科技有限公司 | Novel Micro-LED display array capable of reducing optical crosstalk and preparation method thereof |
| CN214898481U (en) * | 2021-06-23 | 2021-11-26 | 南方科技大学 | Micro-LED display device for reducing pixel optical crosstalk |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115047571A (en) * | 2022-06-27 | 2022-09-13 | 中国科学院半导体研究所 | Film coating structure of optical detector chip |
| CN115047571B (en) * | 2022-06-27 | 2023-12-05 | 中国科学院半导体研究所 | Coating structure of photodetector chip |
| CN116504888A (en) * | 2023-04-27 | 2023-07-28 | 江苏第三代半导体研究院有限公司 | Epitaxial wafer and preparation method and application thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114300594B (en) | 2023-09-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN114300594B (en) | High-efficiency NanoLED structure suitable for near-eye display equipment and manufacturing method thereof | |
| CN109256456B (en) | Microstructure for realizing light efficiency improvement and crosstalk reduction of Micro-LED and manufacturing method thereof | |
| CN109256455B (en) | Full-color Micro-LED display structure with light effect extraction and no pixel interference and manufacturing method thereof | |
| US10295872B2 (en) | Display substrate, display device and manufacturing method the same | |
| WO2017071455A1 (en) | Optical filter and manufacturing method therefor, display substrate, and display apparatus | |
| US9190576B2 (en) | Light emitting device having photonic crystal structure | |
| WO2017197955A1 (en) | Light guiding element and manufacturing method therefor, and backlight module | |
| EP3007240B1 (en) | Display apparatus | |
| TW201211631A (en) | Display device | |
| CN107424524A (en) | A kind of miniature LED display panel | |
| CN108281092B (en) | Micro-structure for extracting display light effect of micron-sized LED and manufacturing method thereof | |
| US9335023B2 (en) | Quantum dot lens and manufacturing method thereof | |
| US9530978B2 (en) | Hollow white composite quantum dot preparation method, display panel and display device | |
| CN110707146B (en) | Cover plate, organic light-emitting display panel and display device | |
| CN113708220B (en) | Quantum dot micro-laser and preparation method thereof | |
| US20230155075A1 (en) | Light emitting devices including a quantum dot color conversion material and method of making thereof | |
| Lin et al. | 59‐1: Invited Paper: A Full‐color Micro‐light‐emitting‐diode Display by a Lithographic‐fabricated Photoresist Mold | |
| US20220131051A1 (en) | Wavelength conversion structure, light-emitting apparatus and display device using the same | |
| CN213750389U (en) | Light guide plate, backlight module with same and liquid crystal display device | |
| US10459285B2 (en) | Polarized RGB light source | |
| CN111785816A (en) | Quantum dot resonant cavity device based on DBR and preparation method | |
| Yu et al. | Enhanced Photoluminescence Intensity of Quantum Dot Films With the Sandwich Column Array Structure by Uniform Electrical Induction | |
| WO2013158038A1 (en) | Hemispherical microstructure arrays for gan-based light emitting diodes and method for forming the arrays | |
| CN117080342B (en) | Light-emitting diode chip and preparation method thereof | |
| Wocheng et al. | P‐12.4: Investigation of Micro‐lens to improve the Efficiency of Micro‐LED Display System |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |