CN116013834A

CN116013834A - Transient substrate and LED chip transfer method

Info

Publication number: CN116013834A
Application number: CN202211631804.2A
Authority: CN
Inventors: 蒲洋; 袁海江
Original assignee: HKC Co Ltd
Current assignee: HKC Co Ltd
Priority date: 2022-12-19
Filing date: 2022-12-19
Publication date: 2023-04-25
Anticipated expiration: 2042-12-19
Also published as: CN116013834B

Abstract

The invention provides a transient substrate and an LED chip transfer method, wherein the transient substrate comprises a first substrate, a second substrate, liquid crystal molecules, a common electrode and a plurality of alignment structures; the first base plate and the second base plate are arranged in a box, liquid crystal molecules are filled between the first base plate and the second base plate, a common electrode is formed on the first base plate, a plurality of alignment structures are formed on the second base plate at intervals, each alignment structure comprises a driving electrode formed on one side of the second base plate, a photosensitive part formed on one side of the second base plate far away from the first base plate, a first electrode and a second electrode formed on one side of the second base plate far away from the first base plate, at least part of each photosensitive part is contacted with the driving electrode, the first electrode is contacted with the photosensitive part, the second electrode is arranged at intervals with the photosensitive part and the driving electrode, and the top surfaces of the first electrode and the second electrode are respectively provided with a photoresist layer. The transient substrate can realize the selective transfer of the LED with normal light emission.

Description

Transient substrate and LED chip transfer method

Technical Field

The invention relates to the technical field of display, in particular to a transient substrate and an LED chip transferring method.

Background

In the process of manufacturing the micro light emitting diode display device, the light emitting diode LED chip formed on the growth substrate needs to be transferred to the driving back plate. The common transfer method is to transfer the LED chip of the growth substrate to the transient substrate, and then pick up the LED chip from the transfer substrate and transfer it to the driving back plate. However, the existing transfer method cannot detect the LED chips in the transfer process, the transfer substrate cannot selectively pick up the LED chips which normally work, the abnormal LED chips and the normal LED chips are transferred to the driving backboard in the batch transfer process, the abnormal LED chips are bound to the driving backboard and then removed and repaired, the driving backboard is difficult to remove and repair, and the driving backboard is damaged due to improper treatment.

Disclosure of Invention

The invention aims to provide a transient substrate and an LED chip transfer method, which aim to detect an LED chip in the transfer process and realize selective transfer of an LED with normal light emission based on a detection result.

In order to solve the technical problems, the invention adopts the following technical scheme:

in one technical scheme of the invention, the invention provides a transient substrate, which comprises a first substrate, a second substrate, liquid crystal molecules, a common electrode and a plurality of alignment structures; the first substrate and the second substrate are arranged in a box-to-box manner, the liquid crystal molecules are filled between the first substrate and the second substrate, the common electrode is formed on the first substrate, the plurality of alignment structures are formed on the second substrate at intervals, the alignment structures are used for being in one-to-one correspondence with the LED chips to be transferred, and the alignment structures comprise:

A driving electrode formed on one side of the second substrate and disposed opposite to the common electrode;

a photosensitive portion formed on a side of the second substrate away from the first substrate, at least a portion of the photosensitive portion being in contact with the driving electrode;

the first electrode and the second electrode are formed on one side, far away from the first substrate, of the second substrate, the first electrode is in contact with the photosensitive part, the second electrode is arranged at intervals with the photosensitive part and the driving electrode, and the top surface of the first electrode and the top surface of the second electrode are respectively provided with a photoresist layer, so that the first electrode and the second electrode are connected one by one through the photoresist layers.

In one of the technical schemes of the invention, the photoresist layer comprises a photoresist main body and conductive particles, wherein the conductive particles are filled in the photoresist main body;

the first electrode and the second electrode are bonded with the two electrodes of the LED chip one by one through the photoresist main body, and the first electrode and the second electrode are connected with the two electrodes of the LED chip one by one in a conductive manner through the conductive particles.

In one of the embodiments of the present invention, the conductive particle includes a conductive core and an insulating shell, the insulating shell coating the conductive core,

The insulating shells of the conductive particles positioned on the top surfaces of the first electrode and the second electrode can be broken by the contraposition pressure when the two electrodes of the LED chip are in contraposition connection with the first electrode and the second electrode one by one, so that the conductive inner core is exposed, and the first electrode and the second electrode are in electric connection with the two electrodes of the LED chip one by one through the conductive inner core.

In one of the technical schemes of the invention, the photolytic layer is arranged in a whole layer and covers the first electrode and the second electrode of each alignment structure.

In one of the technical schemes of the invention, a shading retaining wall is arranged between the adjacent alignment structures;

the orthographic projection of the shading retaining wall on the second substrate is positioned between the orthographic projections of the driving electrodes adjacent to the alignment structure on the second substrate;

and the top surface of the shading retaining wall is higher than the top surfaces of the first electrode and the second electrode.

In one of the embodiments of the present invention, the driving electrode is formed on a side of the second substrate away from the first substrate; wherein,

an insulating layer is arranged between the driving electrode and the first electrode and between the driving electrode and the second electrode, and the insulating layer is provided with a via hole exposing a partial area of the driving electrode;

The first part of the photosensitive part is positioned at one side of the insulating layer away from the second substrate and is contacted with the first electrode, and the second part of the photosensitive part is positioned in the through hole and is contacted with the driving electrode.

In one of the embodiments of the present invention, the common electrode is located at a side of the first substrate facing the second substrate, and is disposed opposite to the driving electrode of each alignment structure.

In one of the embodiments of the present invention, the transient substrate further includes:

the frame glue is adhered between the first substrate and the second substrate, and forms a containing cavity with the first substrate and the second substrate, and the liquid crystal molecules are contained in the containing cavity;

the first polaroid is positioned in the accommodating cavity and is arranged on one side of the second substrate facing the first substrate;

the first alignment film is positioned in the accommodating cavity and is arranged at one side of the first polaroid away from the second substrate;

the second alignment film is positioned in the accommodating cavity and is arranged on one side of the common electrode away from the first substrate;

the second polaroid is arranged on one side of the first substrate far away from the second substrate.

In another technical scheme of the invention, the invention provides an LED chip transferring method, which comprises the following steps:

providing an LED chip array substrate, wherein the LED chip array substrate comprises a growth substrate and a plurality of LED chips positioned on the growth substrate, and two electrodes are arranged on one side of the LED chips, which is away from the growth substrate;

providing the transient substrate, attaching the LED chip array substrate and the transient substrate in an alignment manner, so that two electrodes of the LED chip are connected with the first electrode and the second electrode one by one through the photolytic layer, and removing the growth substrate;

introducing a first voltage to the common electrode, introducing a second voltage to the first electrode of each alignment structure, and introducing a third voltage to the second electrode of each alignment structure, wherein the second voltage is different from the third voltage and is used for driving the LED chips to emit light, the photosensitive parts of the alignment structures are used for being in an electric conduction state when the corresponding LED chips emit light so that the second voltage of the first electrode is applied to the driving electrodes of the alignment structures, and the second voltage is different from the first voltage and is used for forming a light transmission state for driving the liquid crystal molecules to deflect to allow light to pass through;

Providing a transfer substrate, combining the transfer substrate with one side of the LED chip far away from the transient substrate, and irradiating the transient substrate from one side of the common electrode far away from the alignment structure along a direction perpendicular to the transient substrate by using a light source, wherein the light source is used for irradiating a photoresist layer of the alignment structure when the liquid crystal molecules deflect to a light-transmitting state so as to decompose the photoresist layer;

and separating the transfer substrate from the transient substrate so that the normally-luminous LED chips leave the transient substrate and remain on the transfer substrate.

In one of the embodiments of the present invention, after the step of separating the transfer substrate from the transient substrate so that the normal LED chip leaves the transient substrate and remains on the transfer substrate, the transfer method further includes:

and providing a driving backboard, attaching two electrodes of the LED chip reserved on the transferring substrate to the binding area of the driving backboard in a aligned mode, and removing the transferring substrate to transfer the LED chip to the driving backboard.

The invention has the following effective effects:

the transient substrate comprises a first substrate, a second substrate, liquid crystal molecules, a common electrode and a plurality of alignment structures, wherein a driving electrode which is arranged opposite to the common electrode is arranged in the alignment structures, a photosensitive part and a photolytic layer are arranged, the first electrode is contacted with the photosensitive part, a second electrode is arranged at intervals with the photosensitive part and the driving electrode, the top surface of the first electrode and the top surface of the second electrode are both provided with the photolytic layer, when an LED chip is transferred, the LED chip is aligned and attached with the transient substrate, the two electrodes of the LED chip can be connected with the first electrode and the second electrode one by one through the photolytic layer, wherein a first voltage is introduced into the common electrode, a second voltage is introduced into the first electrode, a third voltage is introduced into the second electrode, and the second voltage is different from the first voltage and the third voltage, if the LED chip emits light normally, the light-sensitive part of the alignment structure corresponding to the LED chip is influenced by the illumination of the LED chip and has a reduced resistance value, so that the first electrode and the driving electrode can be conducted, the second voltage can be applied to the driving electrode, an electric field is generated between the common electrode and the driving electrode, the electric field can drive the liquid crystal molecules in the area corresponding to the LED chip to deflect to a light-transmitting state, when the light source is used for irradiating the transient substrate from one side of the first substrate far away from the second substrate along the direction perpendicular to the transient substrate, the light emitted by the light source can pass through the liquid crystal molecules in the light-transmitting state and irradiate the photoresist layer, the photoresist layer is decomposed or the viscosity is reduced under the illumination of the light source, so that no adhesion force or the adhesion force between the two electrodes of the LED chip and the first electrode and the second electrode is very small, the normal LED chip can be conveniently transferred from the transient substrate by using the transfer substrate afterwards, if the LED chip emits light abnormally, the light-sensitive part has larger resistance value so as to insulate the first electrode from the driving motor, thus, the second voltage on the first electrode cannot be applied to the driving electrode, an electric field for driving liquid crystal molecules to deflect to a light transmission state cannot be formed between the driving electrode and the common electrode, that is, the liquid crystal molecules corresponding to the LED chip cannot deflect, light rays of a light source cannot penetrate through the liquid crystal molecules and irradiate a photolysis layer corresponding to the LED chip, two electrodes of the LED chip are still adhered to the first electrode and the second electrode through the photolysis layer with larger adhesive force, thus, when the LED chip is transferred by using the transfer substrate subsequently, the adhesive force between the two electrodes of the abnormal LED chip and the first electrode and the second electrode is larger, and particularly, the adhesive force between the abnormal LED chip and the LED chip is larger, therefore, when the LED chip is transferred by using the transfer substrate, the abnormal LED chip cannot be separated from the transient substrate, thereby realizing the usability screening and the selective transfer of the LED chip in a normal working state, and ensuring that only the LED chip in normal working state can be transferred to the drive transient substrate, and improving the driving yield.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.

Fig. 1 is a schematic structural diagram of a transient substrate according to an embodiment of the invention.

Fig. 2 is another schematic structural diagram of a transient substrate according to an embodiment of the invention.

Fig. 3 is a schematic structural view of a first intermediate structure according to an embodiment of the present invention.

Fig. 4 is a schematic structural view of a second intermediate structure according to an embodiment of the present invention.

Fig. 5 is a schematic structural view of a third intermediate structure according to an embodiment of the present invention.

Fig. 6 is a flowchart of a method for transferring LED chip bulk according to an embodiment of the present invention.

Fig. 7 is a schematic diagram of a structure of a transient substrate and an LED chip aligned and combined according to an embodiment of the invention.

Fig. 8 is a schematic view of a structure of an embodiment of the present invention after removing a growth substrate.

Fig. 9 is a schematic diagram of a structure of the present invention after a first voltage is applied to the common electrode, a second voltage is applied to the first electrode, and a third voltage is applied to the second electrode.

Fig. 10 is a schematic diagram of a structure of an LED chip according to an embodiment of the present invention after being combined with a transfer substrate.

Fig. 11 is a schematic diagram of a structure of a transfer substrate and a transient substrate separated according to an embodiment of the present invention.

The reference numerals are explained as follows:

1. a first substrate, 2, a second substrate; 3. liquid crystal molecules; 4. a common electrode; 5. an alignment structure; 51. a driving electrode; 52. a photosensitive section; 53. a first electrode, 54, a second electrode; 55. a photolytic layer; 551. a photolytic body; 552. conductive particles; 6. a light-shielding retaining wall; 7. an insulating layer; 71. a via hole; 81. a first polarizer; 82. a second polarizer; 91. a first alignment film; 92. a second alignment film; 100. frame glue; 101. a receiving chamber;

200. an LED chip; 201. an electrode;

300. growing a substrate;

400. transferring the substrate; 401. and (5) a glue material.

Detailed Description

While this invention is susceptible of embodiment in different forms, there is shown in the drawings and will herein be described in detail, specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to that as illustrated.

Thus, reference throughout this specification to one feature will be used in order to describe one embodiment of the invention, not to imply that each embodiment of the invention must be in the proper motion. Furthermore, it should be noted that the present specification describes a number of features. Although certain features may be combined together to illustrate a possible system design, such features may be used in other combinations not explicitly described. Thus, unless otherwise indicated, the illustrated combinations are not intended to be limiting.

In the embodiment shown in the drawings, indications of orientation (such as up, down, in, out, left, right, front, back, etc.) are used to explain the structure and movement of the various components of the invention are not absolute but relative. These descriptions are appropriate when the components are in the positions shown in the drawings. If the description of the location of these components changes, then the indication of these directions changes accordingly.

Example embodiments will now be described more fully with reference to the accompanying drawings. However, the exemplary embodiments may be embodied in many forms and should not be construed as limited to the examples set forth herein; rather, these example embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. The drawings are merely schematic illustrations of the present invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus a repetitive description thereof will be omitted.

The invention provides a transient substrate and a transfer method, which can be used for transferring a light-emitting diode device (LED chip), but is not limited to the device, and can also be used for transferring other micro-components. Such as a diode array of a photodiode array detector, a MOS (MetalOxideSemiconductor, MOS) device, a MEMS device of a microelectromechanical system (Micro-Electro-MechanicalSystems, MEMS), etc. The transfer LED chip will be described herein as an example.

Example 1

Fig. 1 to 5 show the structure of a transient substrate according to an embodiment of the invention.

Referring to fig. 1 and 2, in the present embodiment, the transient substrate includes a first substrate 1, a second substrate 2, liquid crystal molecules 3, a common electrode 4, and a plurality of alignment structures 5; wherein the first substrate 1 and the second substrate 2 are arranged in pairs, the liquid crystal molecules 3 are filled between the first substrate 1 and the second substrate 2, the common electrode 4 is formed on the first substrate 1, a plurality of alignment structures 5 are formed on the second substrate 2 at intervals, the alignment structures 5 are used for being in one-to-one correspondence with the LED chips 200 to be transferred, the alignment structures 5 comprise driving electrodes 51, photosensitive parts 52, first electrodes 53 and second electrodes 54, and the driving electrodes 51 are formed on one side of the second substrate 2 and are opposite to the common electrode 4; the photosensitive portion 52 is formed on a side of the second substrate 2 away from the first substrate 1, and at least part of the photosensitive portion 52 is in contact with the driving electrode 51; the first electrode 53 and the second electrode 54 are formed at a side of the second substrate 2 away from the first substrate 1, one of the first electrode 53 and the second electrode 54 is in contact with the photosensitive portion 52, the other is disposed at a distance from the photosensitive portion 52 and the driving electrode 51, and both the top surface of the first electrode 53 and the top surface of the second electrode 54 are provided with a photo resist layer 55 for one-to-one connection with the two electrodes 201 of the LED chip 200 through the photo resist layer 55.

In this solution, a box-shaped space is formed between the first substrate 1 and the second substrate 2, the liquid crystal molecules 3 are filled in the box-shaped space to form a liquid crystal molecule layer, and the liquid crystal molecules in the liquid crystal molecule layer can deflect under the driving of an electric field, so that the alignment structure 5 can be selectively irradiated by the light emitted from the side of the first substrate away from the second substrate along the direction perpendicular to the transient substrate by using the light source. Wherein the common electrode 4 and the driving electrode 51 are used for applying voltages to control the deflection of the liquid crystal molecules 3, thereby realizing the adjustment of the light projection state by controlling the deflection of the liquid crystal molecules 3. Specifically, the liquid crystal molecular layer has at least an opaque state as shown in fig. 1 and a transparent state as shown in fig. 2, and in fig. 2, the liquid crystal molecular layer corresponding to the alignment structure 5 located on the left is in the transparent state. In the initial state of the transient substrate, the long axes of the liquid crystal molecules 3 are arranged along a first direction, for example, in a lying posture as shown in fig. 1, so that the light incident from the side of the first substrate 1 away from the alignment structure 5 cannot pass through the liquid crystal molecular layer to irradiate onto the alignment structure 5, and the liquid crystal molecular layer is in an opaque state. When a voltage difference exists between the common electrode 4 and the driving electrode 51 and the voltage difference is greater than a threshold value, the liquid crystal molecules 3 are driven to deflect so that long axes thereof are arranged along a second direction, and the second direction is different from the first direction, for example, a standing posture as shown in fig. 2, so that light incident from a side of the first substrate 1 away from the alignment structure 5 can be irradiated onto the alignment structure 5 through the liquid crystal molecule layer, and the liquid crystal molecule layer is in a light-transmitting state.

The alignment structure 5 comprises a driving electrode 51, a photosensitive part 52, a first electrode 53, a second electrode 54 and a photolysis layer 55, wherein the driving electrode 51 is formed on one side of the second substrate 2, the photosensitive part 52, the first electrode 53 and the second electrode 54 are formed on one side of the second substrate 2 far away from the first substrate 1, the first electrode 53, the second electrode 54 and the driving electrode 51 are mutually insulated, one end of the photosensitive part 52 is electrically connected with the first electrode 53 and is arranged in an insulating way with the second electrode 54, the other end of the photoresistor is connected with the driving electrode 51, the photolysis layer 55 is arranged on the top surface of the first electrode 53 and the top surface of the second electrode 54, the surface of the first electrode 53 and the second electrode 54 far away from the second substrate 2 is the top surface of the first electrode 53 and the second electrode 54, and the photoresis layer covers the first electrode 53 and the second electrode 54 to adhere to the LED chip 200 to be transferred.

In this technical solution, the alignment structures 5 are used for aligning and combining the LED chips 200, each alignment structure 5 corresponds to one LED chip 200, when the LED chips 200 are aligned and attached to the alignment structures 5, the LED chips 200 are adhered to the photoresist layer 55, and two electrodes 201 of the LED chips 200 are electrically connected with the first electrodes 53 and the second electrodes 54 in a one-to-one correspondence manner through the photoresist layer 55. After the LED chip 200 is combined with the alignment structure 5, a first voltage is applied to the common electrode 4, a second voltage is applied to the first electrode 53, a third voltage is applied to the second electrode 54, the second voltage and the third voltage are different, the light-sensitive portion 52 of the alignment structure 5 is used for driving the LED chip 200 to emit light, the resistance value of the light-sensitive portion is reduced when the corresponding LED chip 200 emits light, so that the first electrode 53 and the driving electrode 51 are in an electrically conductive state, the second voltage of the first electrode 53 is applied to the driving electrode 51 of the alignment structure 5, and the second voltage is different from the first voltage, so that an electric field for driving the liquid crystal molecules to deflect to a light-transmitting state allowing light is formed between the driving electrode 51 and the common electrode 4.

The first voltage may be, for example, a common signal V _com The second voltage may be a positive electrode signal (about 6V) for lighting the LED chip 200, and the third voltage may be a negative electrode signal (-about 3V) for lighting the LED chip 200.

For example, if the first electrode 53 is used to connect the positive electrode of the LED chip 200, the photosensitive portion 52 is connected to the first electrode 53 and the driving electrode 51 respectively, at this time, if the LED chip 200 is in a normal operation, i.e. emits light normally, the photosensitive portion 52 is irradiated by the light emitted by the LED chip 200 and the resistance value is reduced, so that the first electrode 53 is conducted to the driving electrode 51 through the photosensitive portion 52, the voltage input to the first electrode 53 is transmitted to the driving electrode 51, so that the voltage value of the driving electrode 51 is equal to the positive signal value input to the LED chip 200, a voltage difference of about 5V exists between the driving electrode 51 and the common electrode 4, the liquid crystal molecules 3 in the liquid crystal molecular layer corresponding to the LED chip 200 deflect, so that the liquid crystal molecular layer is in a light transmission state, the light emitted by the light source can pass through the first substrate 1, the second substrate 2 and the liquid crystal molecular layer to irradiate the alignment structure 5 corresponding to the LED chip 200 with normal light, and the photo-resist layer 55 is decomposed and the viscosity is reduced, so that the LED chip 200 can be separated from the alignment structure 5.

If the LED chip 200 is abnormal, that is, cannot emit light normally, the resistance value of the photosensitive portion 52 is large, which is equivalent to that the first electrode 53 and the driving electrode 51 are in an insulating state, the voltage input to the first electrode 53 corresponding to the LED chip 200 cannot be transmitted to the driving electrode 51, no voltage difference exists between the driving electrode 51 and the common electrode 4 or the voltage difference does not reach the threshold value for deflecting the liquid crystal molecules 3, the liquid crystal molecules 3 cannot deflect, light can be blocked from passing through, the liquid crystal molecular layer is in an opaque state, and the light emitted by the light source cannot be irradiated to the alignment structure 5 corresponding to the LED chip 200. Therefore, the availability screening and the selective transfer of the LED chips 200 are realized in the transfer process, the LED chips 200 in the normal working state can be separated from the transient substrate, the abnormal LED chips 200 can be directly transferred to other positions for replacement or secondary verification, only the LED chips 200 in the normal working state can be ensured to be transferred to the driving backboard, and the yield of the driving backboard is improved.

Alternatively, the photosensitive portion 52 is a photoresistor, and may be made of selenium, cadmium sulfide, or bismuth sulfide. Alternatively, the first substrate 1 and the second substrate 2 are transparent substrates, and may be transparent organic substrates such as PET substrates, or transparent inorganic substrates such as glass, quartz, sapphire, or the like. Alternatively, the common electrode 4 and the driving electrode 51 may be made of a light-transmitting conductive material such as ITO, IZO, or the like. Alternatively, the first electrode 53 and the second electrode 54 may be made of copper, aluminum. Alternatively, the photo-resist layer 55 may be formed of polyimide, polymethyl methacrylate.

In one of the embodiments of the present invention, as shown in fig. 1, the photoresist layer 55 includes a photoresist main body 551 and conductive particles 552, and the conductive particles 552 are filled in the photoresist main body 551; the first electrode 53 and the second electrode 54 are bonded to the two electrodes 201 of the LED chip 200 one by one through the photoresist body 551, and the first electrode 53 and the second electrode 54 are connected to the two electrodes 201 of the LED chip 200 one by one through the conductive particles 552.

In this technical solution, after the LED chip 200 is aligned and attached to the alignment structure 5, in order to ensure that the two electrodes 201 of the LED chip 200 can pass through the photoresist layer 55 and be electrically connected with the first electrode 53 and the second electrode 54 smoothly, a plurality of conductive particles 552 are dispersed in the photoresist main body 551 of the photoresist layer 55, at least part of the two electrodes 201 of the LED chip 200 passes through the photoresist main body 551 and is adhered to the photoresist main body 551 after the LED chip 200 is aligned and attached to the alignment structure 5, so that the LED chip 200 is kept on the alignment structure 5, and when the two electrodes 201 of the LED chip 200 are aligned and connected with the first electrode 53 and the second electrode 54 in a one-to-one manner, the ends of the two electrodes 201 of the LED chip 200 are pressed on the conductive particles 552 located on the top surfaces of the first electrode 53 and the second electrode 54, so that the first electrode 53 and the second electrode 54 are electrically connected with the two electrodes 201 of the LED chip 200 in one-to-one conductive manner through the conductive particles 552.

In one embodiment of the present invention, the conductive particles 552 include a conductive core and an insulating shell, wherein the insulating shell of the conductive particles 552 on the top surfaces of the first electrode 53 and the second electrode 54 can be broken by an alignment pressure when the two electrodes 201 of the LED chip 200 are aligned with the first electrode 53 and the second electrode 54 one to one, so that the conductive core is exposed, and the first electrode 53 and the second electrode 54 are electrically connected with the two electrodes 201 of the LED chip 200 one to one through the conductive core.

In this solution, as shown in fig. 1, in each alignment structure 5, a photoresist body 551 covers the first electrode 53, the second electrode 54 and the photosensitive part 52, where, to ensure that the conductive particles 552 can be pressed when the two electrodes 201 of the LED chip 200 are connected to the first electrode 53 and the second electrode 54 one by one, more conductive particles 552 are dispersed in the photoresist body 551, and to prevent the conductive particles 552 from conducting the first electrode 53 and the second electrode 54 and conducting the photosensitive part 52 and the second electrode 54, the conductive particles 552 have an insulating shell, specifically, the insulating shell covers the conductive core, and when the two electrodes 201 of the LED chip 200 are connected to the first electrode 53 and the second electrode 54 one by one, the insulating shell of the conductive particles 552 located on the top surfaces of the first electrode 53 and the second electrode 54 is broken by force, and the conductive core leaks the conductive core so that the two electrodes 201 of the first electrode 53 and the second electrode 54 are connected to the LED chip 200 one by one electrically.

In one embodiment of the present invention, the photolytic layer 55 is disposed entirely and covers the first electrode 53 and the second electrode 54 of each alignment structure 5. Therefore, the preparation process of the transient substrate can be simplified, and the process difficulty is reduced.

In one of the embodiments of the present invention, a light shielding wall 6 is disposed between the adjacent alignment structures 5, the orthographic projection of the light shielding wall 6 on the second substrate 2 is located between the orthographic projections of the driving electrodes 51 of the adjacent alignment structures 5 on the second substrate 2, and the top surface of the light shielding wall 6 is higher than the top surfaces of the first electrodes 53 and the second electrodes 54.

In this technical scheme, adjacent alignment structures 5 are separated by the light-shielding retaining wall 6, so that light emitted by the normally-luminous LED chip 200 is prevented from being irradiated onto the photosensitive part 52 of the adjacent alignment structure 5, which results in reduced accuracy and incorrect transfer of the abnormal LED chip 200. The surface of the light-shielding wall 6 far from the second substrate 2 is higher than the surface of the first electrode 53 and the second electrode 54 far from the second substrate 2, so as to improve the light-shielding effect.

In one of the embodiments of the present invention, the driving electrode 51 is formed at a side of the second substrate 2 away from the first substrate 1; wherein an insulating layer 7 is disposed between the driving electrode 51 and the first and

second electrodes

53 and 54, the insulating layer 7 has a via hole 71 exposing a partial region of the driving electrode 51, a first portion of the photosensitive portion 52 is located at a side of the insulating layer 7 away from the second substrate 2 and contacts the first electrode 53, and a second portion of the photosensitive portion 52 is located in the via hole 71 and contacts the driving electrode 51.

In this solution, as shown in fig. 1 and 2, the driving electrode 51 is formed on a side of the second substrate 2 away from the first substrate 1, and is separated from the first electrode 53 and the second electrode 54 by the insulating layer 7, a via hole 71 is formed on the insulating layer 7 at a position close to the first electrode 53, at least a partial region of the driving electrode 51 is exposed by the via hole 71, a first portion of the photosensitive portion 52 is lapped on the side of the insulating layer 7 away from the second substrate 2 and is connected with the first electrode 53, a second portion of the photosensitive portion 52 is laid in the via hole 71 and is connected with the driving electrode 51, and a region of the via hole 71 not occupied by the photosensitive portion 52 is covered by the photolytic layer 55. The shape of the via hole 71 is not limited, and may be trapezoidal as shown, or may be circular, rectangular, square or other irregular shape, and the shape of the photosensitive portion 52 is set to match the shape of the via hole 71.

It is understood that the driving electrode 51 may be formed on a side of the second substrate 2 close to the first substrate 1, so long as a through hole is formed at a position of the second substrate 2 corresponding to the photosensitive portion 52, and a corresponding conductive structure is disposed in the through hole so that the driving electrode 51 and the second portion of the photosensitive portion 52 are electrically connected. Wherein, forming the driving electrode 51 on the side of the second substrate 2 far from the first substrate 1 can reduce the process difficulty, and avoid punching holes on the second substrate 2, so as to ensure the packaging reliability of the liquid crystal molecules 3.

In one embodiment of the present invention, the common electrode 4 is located on a side of the first substrate 1 facing the second substrate 2, and is disposed opposite to the driving electrode 51 of each alignment structure 5.

In this solution, as shown in fig. 1, the common electrode 4 is located on the side of the first substrate 1 facing the second substrate 2, so that its location is close to the liquid crystal molecules 3, and the driving efficiency for deflecting the liquid crystal molecules 3 is higher. The common electrode 4 may have an integral structure as shown in fig. 1, that is, the common electrode 4 corresponds to the driving electrodes 51 of the plurality of alignment structures 5, so that when transferring, only the same first voltage is required to be introduced into the common electrode 4 to perform light emission detection and selective transfer on the LED chip 200 abutted by each alignment structure 5, which has high efficiency. The common electrode 4 may also be in a split structure, that is, the driving electrode 51 of each alignment structure 5 is opposite to one common electrode 4, and the common electrodes 4 of the plurality of alignment structures 5 are arranged at intervals on one side of the first substrate 1 facing the second substrate 2, so that when transferring, a first voltage needs to be respectively introduced into the common electrode 4 of each alignment structure 5.

It will be appreciated that the common electrode 4 may also be located on the side of the first substrate 1 remote from the second substrate 2.

In one of the technical solutions of the present invention, as shown in fig. 1, the transient substrate further includes a sealant 100, a first polarizer 81, a first alignment film 91, a second polarizer 82, and a second alignment film 92, where the sealant 100 is adhered between the first substrate 1 and the second substrate 2, and forms a containing cavity 101 with the first substrate 1 and the second substrate 2, and the liquid crystal molecules 3 are contained in the containing cavity 101; the first polarizer 81 is positioned in the accommodating cavity 101 and disposed at a side of the second substrate 2 facing the first substrate 1; the first alignment film 91 is located in the accommodating cavity 101 and disposed at a side of the first polarizer 81 away from the second substrate 2; the second alignment film 92 is located in the accommodating chamber 101 and is disposed on a side of the common electrode 4 away from the first substrate 1; the second polarizer 82 is disposed at a side of the first substrate 1 remote from the second substrate 2.

In this technical solution, the first substrate 1, the second substrate 2 and the frame glue 100 are enclosed to form a box-shaped accommodating cavity 101, the liquid crystal molecules 3 are filled in the accommodating cavity 101, and the opposite sides of the liquid crystal molecules 3 are respectively provided with a first alignment film 91 and a second alignment film 92 for guiding the alignment of the liquid crystal molecules 3, so that the liquid crystal molecules 3 are aligned in a predetermined direction and angle. The first polarizer 81 is located below the second polarizer 82, and the two polarizers cooperate with the liquid crystal molecules 3 to enable the deflected liquid crystal molecules 3 to change the direction of light, so as to irradiate the alignment structure 5 through the second polarizer 82. In some examples, the polarized light direction of the first polarizer 81 is perpendicular to the polarized light direction of the second polarizer 82.

In one of the embodiments of the present invention, the transient substrate further includes a metal signal line connected to the common electrode 4, the first electrode 53 and the second electrode 54, so as to apply a first voltage to the common electrode 4, a second voltage to the first electrode 53 and a third voltage to the second electrode 54.

In summary, the transient substrate provided by the embodiment of the invention has at least the following beneficial technical effects:

the transient substrate comprises a first substrate 1, a second substrate 2, liquid crystal molecules 3, a common electrode 4 and a plurality of alignment structures 5, wherein by arranging a driving electrode 51 opposite to the common electrode 4 and arranging a photosensitive part 52 and a photolysis layer 55 in the alignment structures 5, the photosensitive part 52 can conduct an electrode 201 and the driving electrode 51 of the LED chip 200 when the LED chip 200 emits light normally, so that an electric field is generated between the common electrode 4 and the driving electrode 51, the electric field can drive the liquid crystal molecules 3 in a region corresponding to the LED chip 200 to deflect, so that light can penetrate and irradiate the alignment structures 5, the viscosity of the photolysis layer 55 is reduced to release the LED chip 200, thereby realizing the availability screening and selective transfer of the LED chip 200 in a transfer process, ensuring that the LED chip 200 in a normal working state can be separated from the transient substrate, ensuring that only the LED chip 200 in a normal working state can be transferred to a driving backboard, and improving the yield of the driving backboard.

As shown in fig. 3 to 5, the transient substrate of the present invention can be prepared by the following process:

providing a first substrate 1, attaching a first polarizer 81 on the back surface of the first substrate 1, forming a common electrode 4 on the front surface of the first substrate 1 by PVD film formation, and forming a first alignment film 91 on the side of the common electrode 4 away from the first substrate 1 by CVD film formation to obtain a first intermediate structure;

providing a second substrate 2, attaching a second polaroid 82 to the back surface of the second substrate 2, forming a second alignment film 92 on one side of the second polaroid 82 far away from the second substrate 2 by CVD film forming, sequentially forming a driving electrode 51, an insulating layer 7, a photosensitive part 52, a first electrode 53 and a second electrode 54 on the front surface of the second substrate 2, and forming a light-shielding retaining wall 6 between adjacent alignment structures 5 to obtain a second intermediate structure;

attaching the side of the first intermediate structure with the first alignment film 91 and the side of the second intermediate structure with the second alignment film 92 in a pair-wise manner, and filling the liquid crystal molecules 3 between the first alignment film 91 and the second alignment film 92 to obtain a third intermediate structure;

and coating photoresist mixed with conductive particles 552 on the side of the light-shielding retaining wall 6 of the third intermediate structure, and curing to obtain the transient substrate.

Wherein, the transient substrate of the present invention is transferred, the liquid crystal molecules 3 are deflected to return to the original state after no electric field is generated between the common electrode 4 and the driving electrode 51, and the photoresist mixed with the conductive particles 552 is coated on the second substrate 2 again for recycling.

Example two

Referring to the drawings, the invention also provides a method for transferring the LED chip 200, as shown in fig. 6, the method for transferring the LED chip 200 comprises the following steps:

s101: an LED chip 200 array substrate is provided, the LED chip 200 array substrate includes a growth substrate 300 and a plurality of LED chips 200 located on the growth substrate 300, and two electrodes 201 are disposed on a side of the LED chips 200 facing away from the growth substrate 300.

Specifically, by providing a growth substrate 300, preparing an epitaxial layer on the growth substrate 300, dividing the epitaxial layer into a plurality of LED epitaxial wafers distributed in a matrix, and mounting an electrode 201 on a side of each LED epitaxial wafer facing away from the growth substrate 300 to obtain the above-mentioned array substrate for the LED chip 200, as shown in fig. 7.

Wherein the material of the growth substrate 300100 may be sapphire (Al ₂ O ₃ ) Any one or more combinations of silicon (Si), silicon carbide (SiC), gallium arsenide (GaAs), aluminum nitride (AlN), zinc oxide (ZnO), etc., may be specifically selected according to the requirements of the device and the LED chip 200, and are not limited solely herein.

The epitaxial layer may be prepared by means of metal organic chemical vapor deposition (metalorganicchemicalvapour deposition, MOCVD), and the material of the epitaxial layer may be any one of GaP, gaN, znO and the like. And further forming patterns by coating photoresist, exposing, developing, etching and removing the photoresist so as to divide the whole epitaxial layer into a plurality of LED epitaxial wafers.

S102: providing a transient substrate, and attaching the LED chip array substrate to the transient substrate in an alignment manner, so that the two electrodes 201 of the LED chip 200 are connected with the first electrode 53 and the second electrode 54 one to one through the photolytic layer 55, and then removing the growth substrate 300.

Specifically, as shown in fig. 7 and 8, the transient substrate is a transient substrate as described above, where the growth substrate 300 may be peeled by a laser peeling method, and a specific operation process may be a laser peeling method commonly used in the art, for example, the gallium nitride layer between the growth substrate 300 and the LED chip 200 may be thermally decomposed by using a laser with a wavelength of 266nm, so as to peel the growth substrate 300.

S103: the first voltage is applied to the common electrode 4, the second voltage is applied to the first electrode 53 of each alignment structure, and the third voltage is applied to the second electrode 54 of each alignment structure 5, the second voltage being different from the third voltage for driving the LED chip 200 to emit light, the light-sensitive portion 52 of the alignment structure 5 being in an electrically conductive state when the corresponding LED chip 200 emits light, such that the second voltage of the first electrode 53 is applied to the driving electrode 51 of the alignment structure 5, the second voltage being different from the first voltage for forming a light-transmitting state for driving the liquid crystal molecules 3 to deflect to allow light to pass through.

Specifically, the common signal Vcom is applied to the common electrode 4, the positive signal is applied to the first electrode 53, the negative signal is applied to the second electrode 54, and the second voltage and the third voltage are different for driving the LED chip 200 to emit light.

As shown in fig. 9, at this time, if the LED chip 200 emits light normally, the light-sensitive portion 52 is irradiated by the light emitted from the LED chip 200 and the resistance value is reduced, so that the first electrode 53 is conducted with the driving electrode 51 through the light-sensitive portion 52, the second voltage input to the first electrode 53 is transmitted to the driving electrode 51, so that the voltage value of the driving electrode 51 is equal to the positive signal value input to the first electrode 53, a voltage difference exists between the driving electrode 51 and the common electrode 4, and the liquid crystal molecules 3 in the liquid crystal molecular layer corresponding to the LED chip 200 are deflected, so that the liquid crystal molecular layer is in a light-transmitting state. If the LED chip 200 is abnormal, the resistance value of the photosensitive portion 52 is large, which corresponds to the first electrode 53 being in an insulated state with the driving electrode 51, the second voltage inputted to the first electrode 53 cannot be transmitted to the driving electrode 51, no voltage difference exists between the driving electrode 51 and the common electrode 4 or the voltage difference does not reach the threshold value for deflecting the liquid crystal molecules 3, the liquid crystal molecules 3 are not deflected, and the liquid crystal molecule layer is in an opaque state.

Specifically, as shown in fig. 9, the LED chip 200 located at the left is in a normal light emitting state, which irradiates the photosensitive portion 52 of the alignment structure 5 opposite thereto by emitting light, so that the resistance value of the photosensitive portion 52 is reduced to turn on the first electrode 53 and the driving electrode 51, whereby a second voltage can be applied to the driving electrode 51, and the liquid crystal molecules 3 are driven to deflect due to a voltage difference between the second voltage and the first voltage, and the liquid crystal molecule layer corresponding to the LED chip 200 is in a light transmitting state.

The LED chip 200 located on the right cannot normally emit light, the first electrode 53 and the driving electrode 51 are in an insulated state due to the large resistance value of the photosensitive portion 52, the second voltage cannot be applied to the driving electrode 51, and the liquid crystal molecules 3 cannot be driven to deflect due to the absence of a voltage difference between the driving electrode 51 and the common electrode 4, so that the liquid crystal molecule layer corresponding to the LED chip 200 is in an opaque state.

S104: a transfer substrate 400 is provided, the transfer substrate 400 is combined with the side of the LED chip 200 away from the temporary substrate, and the temporary substrate is irradiated with a light source from the side of the common electrode 4 away from the alignment structure 5 in a direction perpendicular to the temporary substrate, the light source being used to irradiate onto the photoresist layer 55 of the alignment structure 5 when the liquid crystal molecules are deflected to a light-transmitting state, so that the photoresist layer 55 is decomposed.

Specifically, this step may be provided in a manner commonly used in the art, for example, as shown in fig. 10, a side of the LED chip 200 away from the electrode 201 is attached to the transfer substrate 400 in a pair, the transfer substrate 400 is provided with a glue material 401, the side of the LED chip 200 away from the electrode 201 is combined with the glue material 401, and the LED chip 200 is combined with the transfer substrate 400 by curing the glue material 401. Then, the transient substrate is irradiated from the side of the common electrode 4 far from the alignment structure 5 along the direction perpendicular to the transient substrate by using laser, and the light emitted by the light source can pass through the first substrate 1, the second substrate 2 and the liquid crystal molecular layer corresponding to the normal light emitting LED chip 200 to irradiate onto the corresponding alignment structure 5, so that the photo-resist layer 55 is decomposed to reduce the viscosity, and the LED chip 200 can be separated from the alignment structure 5. The material properties of the glue material 401 on the transfer substrate 400 are different from those of the photolytic layer 55, so that the glue material 401 on the transfer substrate 400 is prevented from being decomposed when the alignment structure 5 is irradiated by light. The adhesive 401 on the transfer substrate 400 may be Polydimethylsiloxane (PDMS). Wherein the laser may use 248nm, 266nm or 355nm ultraviolet light, selected according to the material characteristics of the photolytic layer 55.

Specifically, as shown in fig. 10, since the left LED chip 200 can normally emit light, the corresponding liquid crystal molecule 3 is in a light-transmitting state, and the right LED chip 200 cannot normally emit light, when the transient substrate is irradiated with the same light source from the side of the common electrode 4 away from the alignment structure 5 in a direction perpendicular to the transient substrate, the laser passes through the liquid crystal molecule 3 corresponding to the left LED chip 200 and irradiates the photoresist layer 55 corresponding to the LED chip 200, and the photoresist layer 55 is decomposed by the influence of light, and the viscosity is reduced to release the adhered LED chip 200. The LED chip 200 located on the right cannot normally emit light, the liquid crystal molecules 3 corresponding to the LED chip 200 are in an opaque state, the laser cannot pass through the liquid crystal molecules 3 corresponding to the LED chip 200 located on the right to irradiate onto the photoresist layer 55 corresponding to the LED chip 200, and the LED chip 200 cannot be separated from the photoresist layer 55.

S105: the transfer substrate 400 and the temporary substrate are separated so that the LED chip 200, which normally emits light, is separated from the temporary substrate and remains on the transfer substrate 400.

Specifically, as shown in fig. 11, the transfer substrate 400 is separated from the transient substrate by using an external force or a tool or a transfer device, the LED chip 200 that emits light normally on the left is separated from the photolytic layer 55, picked up by the transfer substrate 400, and the LED chip 200 that emits light abnormally on the right remains on the transient substrate and can be directly transferred to another position for replacement or secondary verification.

In one embodiment of the present invention, after the step of separating the transfer substrate 400 from the transient substrate to separate the LED chip 200 that emits light normally from the transient substrate and remain on the transfer substrate 400, the method further comprises:

providing a driving back plate, attaching the two electrodes 201 of the LED chip 200 remained on the transfer substrate 400 to the binding area of the driving back plate in an aligned manner, and removing the transfer substrate 400 to transfer the LED chip 200 to the driving back plate.

Specifically, the transfer is accomplished by melting tin or indium metal to fix the electrodes 201 of the LED chip 200 to the bonding region of the driving backplate. The specific configuration of the driving circuit board is not limited in the present embodiment, and any control circuit board capable of driving the LED chip 200 to be lighted may be used. In actual production, the driving circuit substrate may include a direct driving circuit substrate and a driving circuit substrate with a complex circuit according to the manner of driving the LED chip 200, which is not described in detail in this embodiment.

While the present application has been described with reference to several exemplary embodiments, it is understood that the terminology used is intended to be in the nature of words of description and illustration rather than of limitation. As the present application may be embodied in several forms without departing from the spirit or essential attributes thereof, it should be understood that the above-described embodiments are not limited by any of the details of the foregoing description, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of such metes and bounds are therefore intended to be embraced by the appended claims.

Claims

1. The transient substrate is characterized by comprising a first substrate, a second substrate, liquid crystal molecules, a common electrode and a plurality of alignment structures; the first substrate and the second substrate are arranged in a box-to-box manner, the liquid crystal molecules are filled between the first substrate and the second substrate, the common electrode is formed on the first substrate, the plurality of alignment structures are formed on the second substrate at intervals, the alignment structures are used for being in one-to-one correspondence with the LED chips to be transferred, and the alignment structures comprise:

2. The transient substrate of claim 1, wherein the photolytic layer comprises a photolytic body and conductive particles, the conductive particles filling within the photolytic body;

3. The transient substrate of claim 2, wherein said conductive particles comprise a conductive core and an insulating shell, said insulating shell encasing said conductive core,

4. The transient substrate of claim 3, wherein said photo-resist layer is disposed entirely over and covering said first and second electrodes of each of said alignment structures.

5. The transient substrate of claim 1, wherein a light-shielding retaining wall is disposed between adjacent alignment structures;

6. The transient substrate of claim 1, wherein the drive electrode is formed on a side of the second substrate remote from the first substrate; wherein,

7. The transient substrate of claim 1, wherein the common electrode is located on a side of the first substrate facing the second substrate and is disposed opposite to the driving electrode of each alignment structure.

8. The transient substrate of claim 7, wherein the transient substrate further comprises:

9. The LED chip transferring method is characterized by comprising the following steps of:

providing the transient substrate according to any one of claims 1 to 7, and attaching the LED chip array substrate to the transient substrate in an aligned manner so that two electrodes of the LED chip are connected to the first electrode and the second electrode one to one through the photolytic layer, and then removing the growth substrate;

and separating the transfer substrate from the transient substrate so that the normal LED chips leave the transient substrate and remain on the transfer substrate.

10. The transfer method of claim 9, further comprising, after the step of separating the transfer substrate from the transient substrate such that normal LED chips leave the transient substrate and remain on the transfer substrate: