CN115799438A

CN115799438A - Micro LED structure, preparation method thereof and light-emitting device

Info

Publication number: CN115799438A
Application number: CN202211626959.7A
Authority: CN
Inventors: 符民; 张珂
Original assignee: Shenzhen Stan Technology Co Ltd
Current assignee: Shenzhen Stan Technology Co Ltd
Priority date: 2022-12-16
Filing date: 2022-12-16
Publication date: 2023-03-14

Abstract

The application provides a micro LED structure, a preparation method thereof and a light-emitting device, and relates to the technical field of light emission. The micro LED structure comprises a light emitting chip and a driving chip, a micro lens array is arranged on the light emitting side of the light emitting chip, and the driving chip is connected with one side of the light emitting chip, which deviates from the micro lens array. The application provides a miniature LED structure can improve the optical energy and scatter, unsharp phenomenon during remote display.

Description

Micro LED structure, preparation method thereof and light-emitting device

Technical Field

The application relates to the technical field of light emitting, in particular to a micro LED structure, a preparation method thereof and a light emitting device.

Background

The Micro-LED (Micro-Light Emitting Diode) technology is to use a self-luminous micron-sized LED as a Light Emitting pixel unit, and assemble the Light Emitting pixel unit on a driving panel to form a high-density LED array. In the related art, the micro LED structure has a problem of unclear remote display.

Disclosure of Invention

In view of the above, an object of the present application is to provide a micro LED structure, a method for manufacturing the same, and a light emitting device.

In order to achieve the purpose, the technical scheme adopted by the application is as follows:

in a first aspect, an embodiment of the present application provides a micro LED structure, including:

the light emitting chip is provided with a plurality of micro lenses on the light emitting side, and the micro lenses are distributed through an array to form a micro lens array;

and the driving chip is connected with one side of the light-emitting chip, which deviates from the micro lens array.

In one embodiment of the first aspect, the light emitting chip includes an epitaxial layer and an electrode layer stacked in sequence, the microlens array is disposed on the epitaxial layer, the electrode layer includes an anode and a cathode, and the anode and the cathode are both disposed on a side of the epitaxial layer away from the microlens array.

In one embodiment of the first aspect, an insulating layer is disposed on a side of the light emitting chip away from the light emitting side, and a through hole is formed in a position of the insulating layer corresponding to the microlens.

In one embodiment of the first aspect, the insulating layer is a dark photoresist layer.

In one embodiment of the first aspect, the microlenses are columnar structures.

In one embodiment of the first aspect, the light emitting chip includes an epitaxial layer, a current spreading layer, an electrode layer, an insulating layer, and a bonding layer, which are sequentially stacked, the microlens array is disposed on the epitaxial layer, the current spreading layer is attached to a side of the epitaxial layer facing away from the microlens array, the electrode layer is attached to a side of the current spreading layer facing away from the epitaxial layer, the insulating layer is attached to surfaces of the epitaxial layer and the electrode layer, and the bonding layer penetrates through the insulating layer to connect the electrode layer with the driving chip;

the epitaxial layer comprises a second semiconductor layer, a light emitting layer and a third semiconductor layer which are sequentially stacked;

one side of the second semiconductor layer is attached to the micro-lens array, and a plurality of bosses arranged at intervals are arranged on the other side of the second semiconductor layer;

the light-emitting layer and the third semiconductor layer are sequentially laminated on the boss end face of the second semiconductor layer to form a step structure;

the electrode layer comprises an anode and a cathode, the anode is arranged on the step surface of the step structure, and the cathode is arranged on the recessed surface of the peripheral side of the second semiconductor layer;

and a current expansion layer is arranged between the electrode layer and the epitaxial layer.

In a second aspect, embodiments of the present application further provide a light emitting device, including the micro LED structure described in the first aspect.

In one embodiment of the first aspect, the light emitting device is a projection apparatus, the projection apparatus comprising:

the micro LED structure according to the first embodiment, wherein the image beam is generated by the light emitting unit;

and the lens is used for projecting the image light beam to form an image picture.

In a third aspect, an embodiment of the present application further provides a method for manufacturing a micro LED structure, including:

generating an initial frame of the light-emitting chip;

arranging an insulating layer on the backlight side of the light-emitting chip initial frame;

bonding and connecting the light-emitting chip initial frame with a driving chip;

and preparing a micro-lens array on the light emergent side of the light emitting chip initial frame.

In one embodiment of the third aspect, the generating the light emitting chip initial frame includes:

sequentially generating a first semiconductor layer, a second semiconductor layer, a light-emitting layer and a third semiconductor layer on the surface of a substrate to form the light-emitting layer;

etching the third semiconductor layer from one side far away from the first semiconductor layer to form a plurality of bosses arranged at intervals, and reserving partial thickness of the second semiconductor layer close to one side of the first semiconductor layer to form a step structure;

and sequentially depositing a current expansion layer and an electrode layer on the step surface of the step structure and the recessed surface at the side of the second semiconductor layer to obtain the initial frame of the light-emitting chip.

In one embodiment of the third aspect, the disposing an insulating layer on the light-emitting chip initial frame backlight side includes:

coating an insulating material on the surfaces of the second semiconductor layer and the electrode layer;

and etching the region of the insulating material, which is positioned in the electrode layer, so as to expose part of the surface of the electrode layer and form an insulating layer.

In one embodiment of the third aspect, the preparing the microlens array on the light-emitting side of the light-emitting chip initial frame includes:

peeling off the substrate to expose the first semiconductor layer;

and etching the first semiconductor layer to obtain the micro-lens array.

In one embodiment of the third aspect, the insulating layer is prepared by:

and coating dark color photoresist materials on the surfaces of the second semiconductor layer and the electrode layer, and etching after exposure and development to obtain the insulating layer.

The application provides a micro LED structure, a preparation method thereof and a light-emitting device. For correlation technique, this application sets up the microlens array through the light-emitting side at the luminescence chip, and driver chip is connected with the one side that the luminescence chip deviates from the microlens array. In the course of the work of miniature LED structure, the less light of luminous angle jets out through microlens array's interface, the great light of luminous angle is by the total reflection at the critical plane, can't send from the light-emitting side of miniature LED structure, the light that sends of luminescence chip is by collimation and convergence, has good spotlight effect, improves the utilization ratio of light, thereby can enough promote image display's definition and display effect, can improve luminous luminance again, and then make the miniature LED structure can generally be applicable to more application scenes. The problem that the miniature LED structure is not clear when displaying remotely in the related art can be improved.

The application provides a miniature LED structure is particularly useful for following electronic equipment: projection devices for remote displays, such as optical projection and the like; applications requiring Display brightness include vehicle-mounted products such as window displays and HUDs (Head Up displays) which are generally used outdoors, sighting glasses and telescopes in the military industry, and Head-mounted devices such as AR glasses, ski glasses and swimming goggles.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

Fig. 1 shows a schematic structural diagram of a related art micro LED structure;

FIG. 2 is a schematic diagram of a micro LED structure without an insulating layer according to some embodiments of the present disclosure;

FIG. 3 illustrates a schematic diagram of a micro LED structure having an insulating layer according to some embodiments of the present application;

FIG. 4 shows a schematic view of the initial structure of the substrate and epitaxial layers in some embodiments of the present application;

FIG. 5 shows a schematic structural view of a stepped structure in some embodiments of the present application;

FIG. 6 is a schematic diagram of the structure of an initial frame of a light-emitting chip in some embodiments of the present application;

FIG. 7 illustrates a schematic diagram of a resulting structure of an insulating layer in some embodiments of the present application;

FIG. 8 illustrates a schematic diagram of a resulting structure of a bonding layer in some embodiments of the present application;

FIG. 9 is a schematic diagram of a connection structure of a driver chip in some embodiments of the present application;

FIG. 10 is a schematic diagram showing a light-emitting chip initial frame after substrate peeling in some embodiments of the present application;

FIG. 11 shows a schematic structural view of a microlens array in some embodiments of the present application;

FIG. 12 is a schematic diagram of a projection device in some embodiments of the present application;

FIG. 13 illustrates a flow chart of a method for fabricating a micro LED structure in some embodiments of the present application;

FIG. 14 illustrates a flow chart of a method for fabricating a light emitting chip starter frame according to some embodiments of the present application;

FIG. 15 is a flow chart of a method for fabricating an insulating layer according to some embodiments of the present application;

FIG. 16 is a flow chart illustrating a method of fabricating a microlens array in some embodiments of the present application.

Description of the main element symbols:

1-a substrate; 2-a first semiconductor layer; 3-a second semiconductor layer; 4-a passivation layer; 5-a light-emitting layer; 6-a third semiconductor layer; 7-a current spreading layer; 8-an electrode layer; 9-a bonding layer; 10-a driver chip;

110-a substrate; 120-an epitaxial layer; 121-a first semiconductor layer; 122-a second semiconductor layer; 123-a light-emitting layer; 124-a third semiconductor layer; 130-current spreading layer; 140-an electrode layer; 150-an insulating layer; 160-a bonding layer; 170-driving the chip; 200-lens.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.

In the description of the present application, it is to be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present application and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the present application.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.

In this application, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral parts; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or may be connected through the use of two elements or the interaction of two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as the case may be.

In this application, unless expressly stated or limited otherwise, a first feature is "on" or "under" a second feature such that the first and second features are in direct contact, or the first and second features are in indirect contact via an intermediary. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

Fig. 1 is a structural diagram of a vertical micro LED structure in the related art. The inventor of this application discovers, and at the course of operation of miniature LED structure, the light emission angle of luminous point is great, causes optical energy to diverge, can appear remote Display unclear scheduling problem, when being applied to products such as optical projection, on-vehicle HUD (Head Up Display, head Up Display system) camera lens especially, remote Display is unclear, greatly influences image definition and the naked eye condition of distinguishing, and Display effect is poor. In addition, a part of the light is totally reflected at the interface position between the first semiconductor layer 2 and the substrate 1, and a part of the totally reflected light is refracted and emitted from the passivation layer 4 at the unlit pixel position, so that optical crosstalk is formed, and the problem of peripheral exposure is also propagated to the outside, thereby affecting the overall display effect of the micro LED structure.

The micro LED structure provided by the scheme can be applied to the projection part of electronic equipment such as optical projection and vehicle-mounted HUD, and can also be applied to the display part of the electronic equipment, for example, the electronic equipment can comprise: any equipment with a display screen, such as a smart phone, a smart watch, a notebook computer, a tablet computer, a vehicle data recorder, a navigator, a head-mounted device and the like.

As shown in fig. 2, the embodiment of the present application provides a micro LED structure, which can effectively collimate and focus light. Meanwhile, light with a larger light-emitting angle is absorbed, so that the light-emitting angle of the micro LED structure is reduced, and the light-emitting efficiency of a light-emitting surface is improved. The problem that a micro LED structure in the related art is not clear when displayed in a long distance is solved.

The micro LED structure comprises a light emitting chip and a driving chip 170, wherein a plurality of micro lenses are arranged on the light emitting side of the light emitting chip and distributed in an array to form a micro lens array _， The driving chip 170 is connected to a side of the light emitting chip facing away from the microlens array.

Specifically, through the setting of microlens array, in the course of the work of miniature LED structure, the less light of luminous angle jets out through microlens array's interface, and the great light of luminous angle is by the total reflection at critical face, can't send from the light-emitting side of miniature LED structure, and the light that the luminescence chip sent is by collimation and convergence, has good spotlight effect, improves the utilization ratio of light, and then can promote image display's definition and display effect.

Further, the light emitting chip includes an epitaxial layer 120, a current spreading layer 130, an electrode layer 140, a bonding layer 160, and a driving chip 170.

Specifically, a lens array is disposed on one side of the epitaxial layer 120, and the light exit side of the micro LED structure is disposed on one side of the epitaxial layer 120 on which the lens array is disposed. The electrode layer 140 includes an anode and a cathode, both disposed on a side of the epitaxial layer 120 facing away from the microlens array. The anode and the cathode may be indirectly connected to the epitaxial layer 120, and a current spreading layer 130 may be disposed between the anode and the epitaxial layer 120 and between the cathode and the epitaxial layer 120, so as to make the current distribution more uniform.

Furthermore, a plurality of step structures are formed by etching the side of the epitaxial layer 120 away from the microlens array, the step structures serve as anode connection terminals of the micro LED structures, and the recessed surfaces on the sides of the epitaxial layer 120 serve as cathode connection terminals of the micro LED structures.

Still further, the epitaxial layer 120 includes a first semiconductor layer 121, a second semiconductor layer 122, a light emitting layer 123, and a third semiconductor layer 124, which are sequentially stacked.

Still further, the first semiconductor layer 121 may be a U-GaN (U-GaN) layer, the second semiconductor layer 122 may be an N-GaN (N-GaN) layer, and the third semiconductor layer 124 may be a P-GaN (P-GaN) layer.

Still further, the micro-lens is in a columnar structure.

Specifically, the first semiconductor layer 121 is etched to form a microlens array, the first semiconductor layer 121 is completely etched to penetrate through the microlens array, a plurality of relatively independent cylinders are formed, and the cylinders are distributed in a matrix to form the microlens array.

In this embodiment, the first semiconductor layer 121 is used to prepare the microlens array, and the prepared cylindrical microlens array can collimate light well. Meanwhile, the cost for preparing the lens array by adopting other materials can be reduced.

One side of the second semiconductor layer 122 is attached to the first semiconductor layer 121, a plurality of bosses are formed at intervals by etching on the other side of the second semiconductor layer 122, and the etching thickness of the second semiconductor layer 122 is smaller than that of the second semiconductor layer 122, so that the side, attached to the first semiconductor layer 121, of the second semiconductor layer 122 is a complete plane and is used for cathode connection of the micro LED structure. The dimensions of each boss may be set to be the same.

The light-emitting layer 123 is provided on the stepped end surface of the second semiconductor layer 122, and performs light-emitting operation after energization, and the third semiconductor layer 124 is provided on the side of the light-emitting layer 123 away from the second semiconductor layer 122. The mesa end surface of the second semiconductor layer 122 is sequentially laminated through the light emitting layer 123 and the third semiconductor layer 124 to form a stepped structure to serve as an anode connection of the micro LED structure.

In some embodiments, as shown in fig. 5, the current spreading layer 130 and the electrode layer 140 are disposed on a side of the epitaxial layer 120 away from the light-emitting side, and the current spreading layer 130 is disposed between the epitaxial layer 120 and the electrode layer 140.

The current spreading layer 130 may be made of at least one of ITO (Indium tin oxide), FTO (Fluorine tin oxide), AZO (aluminum Zinc oxide), or the like.

In this embodiment, the current spreading layer 130 may use ITO as a material.

Specifically, the electrode layer 140 includes an anode disposed in the middle of the epitaxial layer 120 and a cathode disposed at the side of the epitaxial layer 120. That is, the anode is disposed on the end face of the step structure of the epitaxial layer 120, and the cathode is disposed on the recessed plane at the side of the second semiconductor layer 122. A gap is left between the cathode and the step structure.

Further, the electrode layer 140 may be made of a metal material Ti/Al/Ti/Au (titanium/aluminum/titanium/gold) by sequentially depositing metal layers on the light emitting layer 123 by an ion beam evaporation method.

In other embodiments, the electrode layer 140 can also be made of Ni/Fe/Pt/Pd (nickel/iron/platinum/palladium) metal, or other conductive materials.

Still further, the electrode layer 140 may also be formed by depositing a metal in a two-layer structure, such as a Ti/Al electrode or a Ti/Au electrode.

In the application, the electrode layer 140 is formed by sequentially depositing multiple layers of metal to form ohmic contact, so that the resistance value of the electrode is reduced, and the concentration of balanced carriers in a semiconductor can not be obviously changed.

As shown in fig. 3, in some embodiments of the present application, the micro LED structure further comprises an insulating layer 150.

As shown in fig. 7, an insulating layer 150 is further attached to the surface of the epitaxial layer 120 and the electrode layer 140.

Specifically, the insulating layer 150 is attached to a side surface of the second semiconductor layer 122 facing away from the first semiconductor layer 121, and at the same time, the insulating layer 150 covers a part of the surface of the electrode layer 140, even if a part of the surface of the electrode layer 140 is exposed.

In this embodiment, the insulating layer 150 has through holes at the contact portions with the anode and the cathode, and the through holes are located in the central region of the electrode layer 140, so that the center of the electrode layer 140 is exposed.

The insulating layer 150 may be made of dark photoresist material such as black glue or gray glue, which can absorb light, so as to absorb the received light.

In this embodiment, the insulating layer 150 may be made of a black glue photoresist material. The passivation layer in the related art may be replaced by the insulating layer 150 to protect the micro LED structure. Meanwhile, light with a large light emitting angle in the micro LED structure is absorbed, the light beam shaping effect of the micro LED structure is improved, the light emitting angle is converged to about 90 degrees, the effects of high light emitting uniformity and the like are achieved, and the problems of optical crosstalk and peripheral light leakage in the related technology are solved.

In some embodiments of the present disclosure, a step structure is disposed on a side of the epitaxial layer 120 facing away from the microlens, corresponding to the microlens, so that light emitted from the light emitting layer 123 can be emitted from the microlens to the maximum, and meanwhile, the light emitting angle is limited, and the optical crosstalk phenomenon is reduced. The insulating layer 150 is attached to the step structure and is opened with a through hole to allow the electrode layer 140 to leak out.

Referring to fig. 8, in some embodiments of the present disclosure, the bonding layer 160 is disposed on a side of the insulating layer 150 facing away from the epitaxial layer 120, and the bonding layer 160 is connected to the electrode layer 140 through the through hole.

Further, the end faces of the bonding layer 160 on the anode and the cathode are all located at the same level, i.e., the end of the bonding layer 160 away from the electrode layer 140 is kept flush.

Specifically, bonding layer 160 may be formed by depositing a metal material at the through hole, and protruding bonding layer 160 with respect to a side surface of insulating layer 150 away from epitaxial layer 120. The bonding layer 160 may be made of a metal material such as gold, titanium, nickel, aluminum, copper, indium, tin, or silver-tin alloy.

In this embodiment, the bonding layer 160 may be formed by indium metal deposition.

Referring to fig. 10, in some embodiments of the present disclosure, the driving chip 170 is connected to a side of the bonding layer 160 away from the electrode layer 140.

Specifically, the bonding layer 160 is bonded and connected to a pad at a corresponding position on the driving chip 170. The driving chip 170 may be a CMOS (Complementary Metal Oxide Semiconductor) driving chip or a TFT (thin Film Transistor) driving chip.

In this embodiment, the driving chip 170 may be a CMOS driving chip.

The application also provides a light-emitting device which comprises the micro LED structure.

The light-emitting device may be an illuminating portion of an electronic apparatus, for example, the electronic apparatus may include: vehicles, street lights, and the like, any device having a lighting assembly. The light-emitting device may also be a display portion of an electronic apparatus, and for example, the electronic apparatus may include: any equipment with a display screen, such as a smart phone, a smart watch, a notebook computer, a tablet computer, a vehicle data recorder, a navigator, a head-mounted device and the like.

As shown in fig. 12, in some embodiments, the light-emitting device may be a projection apparatus including the above-described micro LED structure and lens 200. The projection device generates an image beam by a light emitting unit; the lens 200 projects the image beam to form an image screen.

Specifically, the lens 200 may have an image zooming function, and by adjusting the focal length of the lens 200, the image light beam generated by the light emitting unit is adaptively projected onto the projected plane, and the size of the image frame on the projection screen can be adjusted.

As shown in fig. 13, an embodiment of the present application further provides a method for manufacturing a micro LED structure, which is used to manufacture the micro LED structure provided in the foregoing embodiment, and includes:

s10, generating an initial frame of the light-emitting chip;

as shown in fig. 6, the light emitting chip initial frame includes a substrate 110, an epitaxial layer 120, a current spreading layer 130, and an electrode layer 140, which are sequentially stacked.

As shown in fig. 14, in some embodiments of the present application, the step S10 may specifically include:

s11, a substrate 110 is selected.

Al may be selected for the substrate 110 according to design requirements ₂ O ₃ (sapphire), si (silicon), siC (silicon carbide), gaAs (gallium arsenide), alN (aluminum nitride), znO (zinc oxide), and the like.

In this embodiment, the substrate 110 is made of Al ₂ O ₃ A (sapphire) substrate 110.

S12, an epitaxial layer 120 is grown on the surface of the substrate 110.

As shown in fig. 4, a first semiconductor layer 121, a second semiconductor layer 122, a light emitting layer 123 and a third semiconductor layer 124 are sequentially formed on the surface of the substrate 110 to form an epitaxial layer 120;

further, the first semiconductor layer 121, the second semiconductor layer 122, the light emitting layer 123 and the third semiconductor layer 124 may be grown by different or the same epitaxial growth methods, respectively. For example, the growth may be performed by at least one of epitaxial growth methods such as a vapor phase epitaxial growth method, a liquid phase epitaxial growth method, or a molecular beam epitaxial growth method, respectively.

And S13, etching the epitaxial layer 120 to generate a plurality of step structures.

As shown in fig. 5, a plurality of spaced apart mesas are formed by etching from the side of the third semiconductor layer 124 away from the first semiconductor layer 121, and are etched to the second semiconductor layer 122, and a portion of the thickness of the second semiconductor layer 122 near the first semiconductor layer 121 is remained, so as to form a step structure.

And S14, sequentially forming a current spreading layer 130 and an electrode layer 140 on the side, away from the substrate 110, of the epitaxial layer 120 by evaporation.

As shown in fig. 6, the electrode layer 140 is disposed on the side of the epitaxial layer 120 away from the substrate 110, the electrode layer 140 disposed on the step structure end surface of the epitaxial layer 120 is an anode, and the electrode layer 140 disposed on the side of the second semiconductor layer 122 and leaking out of the recess plane is a cathode.

A current spreading layer 130 is disposed between the electrode layer 140 and the epitaxial layer 120.

In this embodiment, an ITO material may be deposited on a surface of the epitaxial layer 120 away from the substrate 110 by a magnetron sputtering method to obtain the current spreading layer 130. A Ti/Al/Ti/Au metal layer may be sequentially deposited on a surface of the current spreading layer 130 away from the step structure by an ion beam evaporation method to form an electrode layer 140, and finally, the light emitting chip initial frame is obtained.

And S20, arranging an insulating layer 150 on the backlight side of the light-emitting chip initial frame.

As shown in fig. 15, in some embodiments of the present application, step S20 may specifically include:

and S21, coating an insulating material on the side of the second semiconductor layer 122, which faces away from the microlens array, and on the surface of the electrode layer 140.

And S22, etching the region of the insulating material, which is located in the electrode layer 140, so as to expose part of the surface of the electrode layer 140, and forming the insulating layer 150.

In some embodiments, step S20 may be:

and coating a dark photoresist material on the surfaces of the second semiconductor layer 122 and the electrode layer 140, and etching after exposure and development to obtain the insulating layer 150.

In this embodiment, the insulating material may be a dark photoresist material.

In some embodiments, as also shown in conjunction with fig. 7, the photoresist material may be etched by a dry etch process. The photoresist material is coated on the surface of the electrode layer 140, and a through hole is formed at a contact portion of the insulating layer 150 with the anode and the cathode by etching, and the through hole is located in a central region of the electrode layer 140, so that the center of the electrode layer 140 is exposed, and the subsequent connection with the driving chip 170 is facilitated.

The light resistance material can be made of extinction materials such as black glue or gray glue and the like to absorb received light. In this embodiment, the photoresist material can be a black glue photoresist material. In this case, the insulating layer 150 is a dark insulating layer 150 having a light extinction effect.

And S30, bonding and connecting the light-emitting chip initial frame with the driving chip 170.

As shown in fig. 8 and 9, a bonding layer 160 is deposited at the through hole, and the electrode layer 140 is connected to the driving chip 170 through the bonding layer 160.

Specifically, the bonding layer 160 may be deposited on the electrode layer 140 corresponding to the through hole by a PECVD (Plasma Enhanced Chemical Vapor Deposition) method, and the bonding layer 160 protrudes from a surface of the passivation layer on a side away from the substrate 110, so as to solder an end of the bonding layer 160 away from the substrate 110.

In some embodiments of the present application, the bonding layer 160 may be made of at least one of gold, titanium, nickel, aluminum, copper, indium, tin, or silver-tin alloy. The driving chip 170 may be at least one of the CMOS driving chip 170 or the TFT driving chip 170.

In this embodiment, the bonding layer 160 may be formed by indium deposition, and the driving chip 170 may be a CMOS driving chip 170. Indium balls are formed through indium reflux of the bonding layer 160 and are connected with the driving chip 170 through ball bonds, and a basic display screen frame is obtained.

And S40, preparing a micro-lens array on the light emergent side of the light emitting chip initial frame.

As shown in fig. 16, in some embodiments of the present application, step S40 may specifically include:

s41, peeling the substrate 110 to expose the first semiconductor layer 121;

as shown in fig. 10, the substrate 110 may be removed by LLO (Laser Lift-off) based on the basic display frame.

Since the insulating layer 150 is formed in the basic display screen frame, the laser beam of the llo can be better aligned to the interface between the sapphire and the first semiconductor layer 121, thereby improving the laser lift-off effect.

S42, etching the first semiconductor layer 121 to obtain a microlens array.

As also shown in fig. 11, a mask is deposited on the first semiconductor layer 121 to form a mask matrix. In the application, the mask material is SiO ₂ (Quartz).

Next, the area of the first semiconductor layer 121 not covered by the mask may be etched through a photolithography process to obtain a microlens array.

In an embodiment, the plurality of cylindrical lenses distributed in an array may be opposite to the electrode layers 140 in the micro LED structure in a one-to-one correspondence manner, that is, the plurality of cylindrical lenses correspondingly cover the plurality of electrode layers 140 in a one-to-one correspondence manner.

In summary, the microlens array is disposed on the light emitting side of the light emitting chip, and the driving chip 170 is connected to the side of the light emitting chip departing from the microlens array. In the working process of the micro LED structure, light with a small light emitting angle is emitted through the interface of the micro lens array, light emitted by the light emitting chip is collimated and converged, a good light condensing effect is achieved, the utilization rate of the light is improved, and then the definition and the display effect of image display can be improved. Meanwhile, light rays with a large light emitting angle are totally reflected on a critical surface and absorbed by the insulating layer 150, and cannot be emitted from the light emitting side of the micro LED structure, so that the problem that the micro LED structure is not clear in remote display in the related technology is solved.

In the description herein, reference to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application, and that variations, modifications, substitutions and alterations may be made to the above embodiments by those of ordinary skill in the art within the scope of the present application.

Claims

1. A micro LED structure, comprising:

2. The micro LED structure of claim 1, wherein the light emitting chip comprises an epitaxial layer and an electrode layer stacked in sequence, the micro lens array is disposed on the epitaxial layer, the electrode layer comprises an anode and a cathode, and the anode and the cathode are both disposed on a side of the epitaxial layer away from the micro lens array.

3. The micro LED structure of claim 1, wherein an insulating layer is disposed on a side of the light emitting chip away from the light emitting side, and a through hole is disposed at a position of the insulating layer corresponding to the micro lens.

4. The micro LED structure of claim 3, wherein the insulating layer is a dark photoresist layer.

5. The micro LED structure according to any one of claims 1 to 4, wherein the micro lens is a cylindrical structure.

6. The micro LED structure according to claim 1, wherein the light emitting chip includes an epitaxial layer, a current spreading layer, an electrode layer, an insulating layer, and a bonding layer stacked in sequence, the microlens array is disposed on the epitaxial layer, the current spreading layer is attached to a side of the epitaxial layer facing away from the microlens array, the electrode layer is attached to a side of the current spreading layer facing away from the epitaxial layer, the insulating layer is attached to surfaces of the epitaxial layer and the electrode layer, and the bonding layer penetrates through the insulating layer to connect the electrode layer with the driving chip;

the electrode layer comprises an anode and a cathode, the anode is arranged on the step surface of the step structure, and the cathode is arranged on the concave surface on the peripheral side of the second semiconductor layer;

the current expansion layer is arranged between the electrode layer and the epitaxial layer.

7. A light-emitting device, comprising: the micro LED structure of any one of claims 1-6.

8. The lighting apparatus according to claim 7, wherein the lighting apparatus is a projection device, the projection device comprising:

the micro LED structure generates image light beams through the light emitting unit;

9. A preparation method of a micro LED structure is characterized by comprising the following steps:

generating an initial frame of the light-emitting chip;

10. The method of claim 9, wherein the step of forming a light-emitting chip initial frame comprises:

sequentially generating a first semiconductor layer, a second semiconductor layer, a light emitting layer and a third semiconductor layer on the surface of a substrate to form an epitaxial layer;

11. The method for fabricating a micro LED structure according to claim 10, wherein the disposing an insulating layer on the back light side of the light emitting chip original frame comprises:

12. The method of claim 11, wherein the step of fabricating the micro-lens array on the light-emitting side of the light-emitting chip initial frame comprises:

peeling off the substrate to expose the first semiconductor layer;

and etching the first semiconductor layer to obtain the micro-lens array.

13. The method for manufacturing a micro LED structure according to any one of claims 10 to 12, wherein the insulating layer is manufactured by: