CN113990765B

CN113990765B - Preparation method of flexible light-emitting device, flexible light-emitting device and light-emitting device

Info

Publication number: CN113990765B
Application number: CN202111618977.6A
Authority: CN
Inventors: 刘召军; 张珂; 周玮
Original assignee: Shenzhen Stan Technology Co Ltd
Current assignee: Shenzhen Stan Technology Co Ltd
Priority date: 2021-12-28
Filing date: 2021-12-28
Publication date: 2023-04-18
Anticipated expiration: 2041-12-28
Also published as: CN113990765A

Abstract

The disclosure provides a preparation method of a flexible light-emitting device, the flexible light-emitting device and a light-emitting device. The method comprises the following steps: providing a micro LED array prepared on a first substrate and providing a TFT array prepared on a heat resistant adhesive disposed on a second substrate; transferring the micro LED array from the first substrate to a third substrate by means of adhesive glue and by two transfers, so that the electrodes of the micro LED array are exposed; bonding electrodes of the micro LED array transferred onto the third substrate with electrodes of the TFT array; removing the second substrate to expose the heat-resistant glue; fixing the connected micro LED array and TFT array on the flexible substrate through heat-resistant glue; and removing the third substrate. According to the scheme, the micro LED array can be connected with the TFT array after twice transfer, and the whole body can be reliably and efficiently fixed on various flexible substrates, so that different functions can be realized.

Description

Preparation method of flexible light-emitting device, flexible light-emitting device and light-emitting device

Technical Field

The disclosure relates to the technical field of semiconductor LEDs, in particular to a preparation method of a flexible light-emitting device, the flexible light-emitting device and a light-emitting device.

Background

The micro LED has the advantages of being smaller, higher in resolution ratio, higher in brightness, higher in luminous efficiency, lower in power consumption, good in controllability and the like, and with the development of the micro LED, the micro LED is applied to various different products except a display screen. However, the application of micro LEDs is mainly based on rigid carriers, and is not well suited for flexible carriers, which greatly limits the application of micro LEDs.

Disclosure of Invention

In order to solve the technical problems mentioned in the background art, the present disclosure provides a method for manufacturing a flexible light emitting device, and a light emitting apparatus.

According to an aspect of the embodiments of the present disclosure, there is provided a method for manufacturing a flexible light emitting device, wherein the method includes: providing a micro LED array prepared on a first substrate and providing a TFT array prepared on a heat resistant adhesive disposed on a second substrate; transferring the micro LED array from the first substrate to a third substrate by means of adhesive glue and through two transfers, so that the electrodes of the micro LED array are exposed; bonding electrodes of the micro LED array transferred onto the third substrate with electrodes of the TFT array; removing the second substrate to expose the heat-resistant glue; fixing the micro LED array and the TFT array which are connected together on a flexible substrate through heat-resistant glue; and removing the third substrate.

Further, the transferring the micro LED array from the first substrate to a third substrate with an adhesive glue and by two transfers such that the electrodes of the micro LED array are exposed comprises: fixing the exposed electrodes of the micro LED array on a temporary substrate through first adhesive glue; removing the first substrate to expose an electrode-facing portion of the micro LED array that faces the electrode; fixing the electrode opposite part on the third substrate through second adhesive glue; and removing the first adhesive and the temporary substrate to expose the electrodes of the micro LED array.

Further, the bonding the electrodes of the micro LED array transferred onto the third substrate with the electrodes of the TFT array includes: and bonding the electrodes of the micro LED array and the electrodes of the TFT array through flip chip bonding.

Further, after removing the third substrate, the method further includes: and packaging the LED array and the TFT array which are connected together by arranging a flexible packaging layer.

Further, the flexible packaging layer comprises packaging glue.

Further, the material of the flexible substrate includes cloth or plastic.

Further, the first substrate, the second substrate, the third substrate, and the temporary substrate each include a rigid substrate.

Further, the first substrate includes a sapphire substrate.

Further, the removing the first substrate to expose an electrode-opposing portion of the micro LED array opposing the electrode includes: and decomposing a part of the semiconductor layer of the micro LED array at the joint with the sapphire substrate by using first ultraviolet laser so as to strip the sapphire substrate and expose the rest part of the semiconductor layer.

Further, the semiconductor layer is a GaN layer, and the wavelength of the first ultraviolet laser is 257nm.

Further, the temporary substrate comprises a silicon wafer substrate or a copper substrate.

Further, the removing the first adhesive and the temporary substrate to expose the electrodes of the micro LED array includes: and dissolving the first adhesive glue by using an acetone solution so as to remove the first adhesive glue and the silicon wafer substrate and expose the electrodes of the micro LED array.

Further, the second substrate comprises a glass substrate, a sapphire substrate or a quartz substrate, and the heat-resistant glue comprises polyimide glue.

Further, the removing the second substrate and exposing the heat-resistant glue includes: and melting the polyimide glue through a second ultraviolet laser to remove the glass substrate and expose the polyimide glue.

Further, the wavelength of the second ultraviolet laser is 308nm.

Further, the third substrate comprises a sapphire substrate, a glass substrate or a quartz substrate, and the second adhesive glue comprises UV (ultraviolet) anti-adhesive glue.

Further, the removing the third substrate includes: reducing the viscosity of the UV viscosity-reducing adhesive through a third ultraviolet laser to remove the UV viscosity-reducing adhesive and the sapphire substrate.

Further, the wavelength of the third ultraviolet laser is between 350nm and 380 nm.

According to another aspect of the present disclosure, there is also provided a flexible light emitting device. The flexible light-emitting device is prepared by the preparation method of the flexible light-emitting device.

According to still another aspect of the disclosed embodiments, there is also provided a light emitting device. The light-emitting device comprises the flexible light-emitting device and a control circuit connected with the flexible light-emitting device.

By applying the technical scheme, the miniature LED array can be replaced by the substrate which is easy to remove after being transferred twice and connected with the TFT array for driving the miniature LED array, and then the miniature LED array and the TFT array which are fixedly connected together are adhered to the flexible substrate through the heat-resistant glue, so that the miniature LED array and the TFT array can be integrally, reliably and efficiently fixed on various flexible substrates, the flexible light-emitting device can be applied to various flexible products, and different functions are realized.

Drawings

The above and other objects, features and advantages of exemplary embodiments of the present disclosure will become readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. Several embodiments of the present disclosure are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar or corresponding parts and in which:

fig. 1 is a flow chart illustrating a method of making a flexible light emitting device according to one embodiment of the present disclosure;

fig. 2 a-2 k are schematic diagrams illustrating a fabrication process flow of a method of fabricating a flexible light emitting device according to one embodiment of the present disclosure.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present disclosure will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

For ease of description, spatially relative terms such as "over ...,"' over ...upper surface "," above ", etc. may be used herein to describe the spatial relationship of one device or feature to another device or feature as shown in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary terms "at ...above" may include both orientations "at ...above 8230; 'at 8230;' below 8230;" above ". The device may also be oriented 90 degrees or at other orientations and the spatially relative descriptors used herein interpreted accordingly.

Exemplary embodiments according to the present disclosure will now be described in more detail with reference to the accompanying drawings. These exemplary embodiments may, however, be embodied in many different forms and should not be construed as limited to only the embodiments set forth herein. It is to be understood that these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art, in the drawings, the thicknesses of layers and regions are exaggerated for clarity, and the same devices are denoted by the same reference numerals, and thus the description thereof will be omitted.

The present disclosure provides a method of fabricating a flexible light emitting device. Referring to fig. 1, fig. 1 is a flowchart illustrating a method of manufacturing a flexible light emitting device according to one embodiment of the present disclosure. As shown in fig. 1, the method for manufacturing the flexible light emitting device includes the following steps S101 to S106.

Step S101 of providing a micro LED array prepared on a first substrate and providing a TFT array prepared on a heat resistant adhesive disposed on a second substrate.

And S102, transferring the micro LED array from the first substrate to a third substrate by means of adhesive glue and through two transfers, so that the electrodes of the micro LED array are exposed.

And S103, bonding the electrodes of the micro LED array transferred to the third substrate with the electrodes of the TFT array.

And step S104, removing the second substrate to expose the heat-resistant glue.

And S105, fixing the connected micro LED array and the TFT array on a flexible substrate through heat-resistant glue.

And step S106, removing the third substrate.

According to the technical scheme, the miniature LED array can be replaced by the substrate which is easy to remove after being transferred twice and is connected with the TFT array used for driving the miniature LED array, and then the miniature LED array and the TFT array which are fixedly connected together are adhered to the flexible substrate through the heat-resistant glue, so that the miniature LED array and the TFT array can be integrally, reliably and efficiently fixed on various flexible substrates, the flexible light-emitting device can be applied to various flexible products, and different functions are realized.

In step S101, a micro LED array prepared on a first substrate and a TFT array prepared on a thermal resistant adhesive disposed on a second substrate may be provided.

According to an embodiment of the present disclosure, in order to manufacture a flexible light emitting device, a micro LED array for emitting light, which is manufactured on a first substrate, and a TFT (thin film transistor) array for driving the micro LED array, which is manufactured on a heat-resistant adhesive disposed on a second substrate, may be first obtained. The heat resistant temperature of the heat resistant glue enables the TFT array to be prepared on the micro LED array and the TFT array in advance, and the micro LED array and the TFT array can also be prepared in the preparation method of the flexible light emitting device disclosed by the disclosure.

For micro LED arrays and TFT arrays, the first substrate and the second substrate may comprise rigid substrates. Further, the first substrate includes a sapphire substrate. The second substrate comprises a glass substrate, a sapphire substrate or a quartz substrate, and the heat-resistant glue comprises polyimide glue. The polyimide glue may be formed by coating a polyimide glue on the second substrate. The heat resistant glue may also be any other glue that is resistant to high temperatures and suitable for the fabrication of TFT arrays thereon. Referring to fig. 2a to 2k, fig. 2a to 2k are schematic views of a manufacturing process flow illustrating a method of manufacturing a flexible light emitting device according to one embodiment of the present disclosure. Wherein figure 2a shows a micro LED array 10 with a sapphire substrate 11 according to one embodiment of the present disclosure. The micro LED array 10 is epitaxially grown on a sapphire substrate 11. Each micro LED in the array of micro LEDs includes an exposed electrode. As shown in fig. 2a, each micro LED101 in the micro LED array 10 comprises an exposed cathode 1011, which cathode 1011 is adapted to be connected to an electrode of the TFT array so that the micro LED array is driven by the TFT array. Fig. 2b shows a TFT array 20 prepared on a glass substrate 21 provided with a polyimide glue 22 according to one embodiment of the present disclosure. Each TFT in the TFT array includes an exposed electrode. As shown in fig. 2b, each TFT201 in the TFT array 20 includes an exposed drain 2011, which is used to connect with the cathode 1011 of the micro LED array 10 shown in fig. 2a so that the TFT array 20 drives the micro LED array 10.

According to an embodiment of the present disclosure, a method of fabricating a TFT array on a second substrate provided with a polyimide paste may include: spin-coating a polyimide paste on the second substrate, and then depositing an insulating layer on the polyimide paste using a CVD or spin-coating method, wherein the material of the insulating layer may be spin-on glass (SOG) or silicon dioxide; sputtering a metal layer on the insulating layer, and patterning the metal layer into a back gate of the TFT through photoetching, dry etching and photoresist removing steps, wherein the metal layer can be made of molybdenum for example; depositing a gate insulating layer on the insulating layer and the back gate by using a Plasma Enhanced Chemical Vapor Deposition (PECVD) method, wherein the temperature is controlled below 300 ℃, and the material of the gate insulating layer can be silicon dioxide; sputtering an active layer metal oxide on the gate insulating layer, and patterning the active layer metal oxide into an active island, a source electrode and a drain electrode through photoetching, dry etching and photoresist removing steps, wherein the active layer metal oxide can be Indium Gallium Zinc Oxide (IGZO), zinc oxide (ZnO) and the like; depositing a passivation layer on the gate insulating layer, the active island, the source electrode and the drain electrode, and then performing oxygen annealing, wherein the temperature is controlled to be lower than 300 ℃ and the time is adjusted as required during the oxygen annealing, and the passivation layer can be made of silicon dioxide; photoetching, etching and removing photoresist on the passivation layer to pattern a contact hole, wherein the contact hole exposes a source electrode region and a drain electrode region; sputtering metal electrode layers on the source electrode region and the drain electrode region, and patterning the metal electrodes, wherein the metal electrode layers can be made of molybdenum, aluminum or a multi-layer metal combination; and depositing an insulating protective layer on the metal electrode, patterning a contact hole to expose the metal electrode corresponding to the drain region, and depositing a metal electrode connecting pad in the contact hole to form the drain. It is noted that, when a TFT array is manufactured on the polyimide paste, the temperature needs to be controlled below 300 degrees celsius because the heat-resistant temperature of the polyimide paste is 300 degrees celsius. Due to the high heat resistance of the polyimide adhesive, the TFT array can be prepared on the polyimide adhesive, so that the TFT array can be pasted on the substrate by using the polyimide adhesive after the substrate is removed, and the preparation of the light-emitting device on the flexible substrate is particularly convenient.

In step S102, the micro LED array may be transferred from the first substrate to a third substrate by two transfers with an adhesive glue such that electrodes of the micro LED array are exposed.

According to the embodiment of the present disclosure, in order to facilitate subsequent preparation operations, after two transfers, the micro LED array needs to be attached to the third substrate by an adhesive glue and still keep the exposed electrodes before transferring exposed, so as to facilitate subsequent operations to remove the third substrate and the adhesive glue without damaging other parts.

In a first embodiment, the transferring the micro LED array from the first substrate to a third substrate by means of an adhesive glue and by two transfers, such that the electrodes of the micro LED array are exposed, may comprise: fixing the exposed electrodes of the micro LED array on a temporary substrate through first adhesive glue; removing the first substrate to expose an electrode-facing portion of the micro LED array that faces the electrode; fixing the electrode opposite part on the third substrate through second adhesive glue; and removing the first adhesive and the temporary substrate to expose the electrodes of the micro LED array. Thus, for this first embodiment, both transfers of the micro LED array are by means of an adhesive glue.

Wherein the third substrate and the temporary substrate may each comprise a rigid substrate. Specifically, the temporary substrate may include a silicon wafer substrate or a copper substrate, and the first adhesive glue may be any glue suitable for fixing the micro LED array on the temporary substrate, that is, the glue may be dissolved by a specific solvent, and the specific solvent may not damage the micro LED array. The third substrate may include a sapphire substrate, a glass substrate, or a quartz substrate, and the second adhesive paste may include a UV-curable adhesive paste.

The micro LED array is replaced with its substrate by two transfers as will be described in detail below.

First, a temporary substrate may be added for the micro LED array with the first substrate. Referring to fig. 2 a-2 k, fig. 2 a-2 k are process flow diagrams illustrating a method of fabricating a flexible light emitting device according to an embodiment of the present disclosure. Wherein figure 2c shows the micro LED array 10 secured to a silicon wafer substrate 12 by a first adhesive glue 13. As shown in fig. 2c, a first adhesive glue 13 may be coated on the silicon wafer substrate 12, the micro LED array 10 with the sapphire substrate 11 as shown in fig. 2a is turned over so that the exposed cathode 1011 of the micro LED array 10 faces the first adhesive glue 13, and then pressure is applied to the micro LED array 10 through the sapphire substrate 11, so that the exposed cathode 1011 of the micro LED array 10 is adhered to the silicon wafer substrate 12 through the first adhesive glue 13, thereby fixing the micro LED array 10 on the silicon wafer substrate 12.

Secondly, the original first substrate can be removed, and the first transfer of the micro LED array is realized. Specifically, the removing the first substrate to expose an electrode opposing portion of the micro LED array opposing the electrode may include: and decomposing a part of the semiconductor layer of the micro LED array at the joint with the sapphire substrate by using first ultraviolet laser so as to strip the sapphire substrate and expose the rest part of the semiconductor layer.

Referring to fig. 2a to 2k, fig. 2a to 2k are schematic views of a manufacturing process flow illustrating a method of manufacturing a flexible light emitting device according to one embodiment of the present disclosure. Wherein figure 2d shows the micro LED array with the sapphire substrate 11 removed. After the micro LED array 10 is fixed on the silicon wafer substrate 12, as shown in fig. 2d, a part of a semiconductor layer of the micro LED array 10 at a junction with the sapphire substrate 11, that is, a part at a junction of a first semiconductor layer epitaxially grown on the sapphire substrate and the sapphire substrate, may be decomposed by passing a first ultraviolet laser 31 through the sapphire substrate 11, which does not affect the performance of the micro LED array, so that the sapphire substrate 11 may be separated from the micro LED array 10, and the sapphire substrate 11 may be peeled off and the first semiconductor layer may be exposed. It should be noted that the specific semiconductor layers of the micro LED array are not shown in the figures, i.e. the first semiconductor layer is not shown. The first semiconductor layer may be a GaN layer, and the first ultraviolet laser light 31 has a wavelength of 257nm in order to pass through the sapphire substrate 11 and decompose a portion of GaN. Uv laser light at 257nm is more favorable to penetrate the sapphire substrate and decompose GaN. It should be noted that the first ultraviolet laser 31 is represented by three lines with arrows in the drawing and the irradiation direction is inclined, which is merely a schematic representation of the first ultraviolet laser and does not limit the coverage and direction of the first ultraviolet laser.

Next, a third substrate may be added for the micro LED array with the temporary substrate. Referring to fig. 2a to 2k, fig. 2a to 2k are schematic views of a manufacturing process flow illustrating a method of manufacturing a flexible light emitting device according to one embodiment of the present disclosure. Wherein figure 2e shows the micro LED array 10 secured to the sapphire substrate 14 by a UV-detackifying glue 15. As shown in fig. 2e, a UV adhesive 15 may be coated on the sapphire substrate 14, the micro LED array 10 with the silicon substrate 12 is turned over to make the exposed semiconductor layer of the micro LED array 10 face the UV adhesive 15, and then pressure is applied to the micro LED array 10 through the silicon substrate 12, so that the exposed semiconductor layer of the micro LED array 10 is adhered to the sapphire substrate 14 through the UV adhesive 15, and thus the micro LED array 10 is fixed on the sapphire substrate 14.

And finally, removing the first adhesive and the temporary substrate to realize the second transfer of the micro LED array. Specifically, the removing the first adhesive and the temporary substrate to expose the electrodes of the micro LED array may include: and dissolving the first adhesive glue by using an acetone solution so as to remove the first adhesive glue and the silicon wafer substrate and expose the electrodes of the micro LED array.

Referring to fig. 2a to 2k, fig. 2a to 2k are schematic views of a manufacturing process flow illustrating a method of manufacturing a flexible light emitting device according to one embodiment of the present disclosure. Wherein fig. 2f shows the micro LED array 10 after the first adhesive 13 and the silicon wafer substrate 12 are removed. The micro LED array 10 with the silicon wafer substrate 12 shown in fig. 2e may be soaked in an acetone solution, the first adhesive glue 13 is dissolved by the acetone solution, after the first adhesive glue 13 is dissolved, the silicon wafer substrate 12 thereon may be naturally separated from the micro LED array 10, and then the silicon wafer substrate 12 may be removed, so as to obtain the structure shown in fig. 2 f. The first adhesive glue and silicon wafer substrate are removed in this step using an acetone solution without additional damage to the structure containing the micro LED array (as shown in fig. 2 e) in the current fabrication process.

As shown in fig. 2f, the micro LED array is exchanged after two transfers from the first substrate (e.g. sapphire substrate) to a third substrate (e.g. sapphire substrate provided with UV-vis).

In a second embodiment, the transferring the micro LED array from the first substrate to a third substrate by means of an adhesive glue and by two transfers such that the electrodes of the micro LED array are exposed may comprise: welding and fixing the exposed electrode of the micro LED array on a welding spot on a temporary substrate of a silicon wafer by laser welding; removing the first substrate to expose an electrode-facing portion of the micro LED array that faces the electrode; fixing the electrode opposing portion on the third substrate by a second adhesive paste; and removing the silicon wafer temporary substrate by penetrating a welding spot through the silicon wafer temporary substrate by laser to expose the electrodes of the micro LED array. With this second embodiment, only the first step and the fourth step are different from the first embodiment. Therefore, the micro LED array is transferred to the third substrate only by means of the adhesive glue.

In step S103, the electrodes of the micro LED array transferred onto the third substrate may be bonded with the electrodes of the TFT array.

According to the embodiment of the disclosure, after the micro LEDs are replaced with the substrate, the replaced micro LEDs can be bonded with the TFT array. Specifically, the bonding the electrodes of the micro LED array transferred onto the third substrate with the electrodes of the TFT array includes: and bonding the electrodes of the micro LED array and the electrodes of the TFT array by flip-chip bonding.

Referring to fig. 2a to 2k, fig. 2a to 2k are schematic views of a manufacturing process flow illustrating a method of manufacturing a flexible light emitting device according to one embodiment of the present disclosure. Wherein figure 2g shows the micro LED array 10 connected together with the TFT array 20. As shown in fig. 2g, the micro LED array 10 with the sapphire substrate 14 provided with the UV-detackifying glue 15 as shown in fig. 2f is turned over, and the cathode 1011 of the micro LED array 10 is bonded and connected to the drain 2011 of the TFT array 20 with the glass substrate 21 provided with the polyimide glue 22 as shown in fig. 2b by flip chip bonding, so that the micro LED array 10 and the TFT array 20 are connected together.

In step S104, the second substrate may be removed to expose the heat-resistant adhesive.

According to embodiments of the present disclosure, after connecting the micro LED array and the TFT array together, the second substrate may be removed. Specifically, the removing the second substrate to expose the heat-resistant glue may include: and melting the polyimide glue through a second ultraviolet laser to remove the glass substrate and expose the polyimide glue. The wavelength of the second ultraviolet laser is 308nm.

Referring to fig. 2 a-2 k, fig. 2 a-2 k are process flow diagrams illustrating a method of fabricating a flexible light emitting device according to an embodiment of the present disclosure. Wherein figure 2h shows the TFT array with the micro LED array attached when the glass substrate 21 of the TFT array 20 is removed. After inverting the structure shown in fig. 2g, the glass substrate 21 may be removed and the polyimide glue 22 may remain by a second ultraviolet laser 32 through the glass substrate 21 and melting the polyimide glue 22, as shown in fig. 2 h. The wavelength of the second ultraviolet laser 32 is 308nm in order to penetrate the glass substrate 21 and melt the polyimide paste 22. An ultraviolet laser having a wavelength of 308nm is more advantageous to penetrate the glass substrate 21 and melt the polyimide paste 22. It should be noted that the second ultraviolet laser 32 is represented by three lines with arrows in the drawing and the irradiation direction is inclined, which is merely a schematic representation of the second ultraviolet laser and does not limit the coverage and direction of the second ultraviolet laser.

In step S105, the micro LED array and the TFT array connected together may be fixed on a flexible substrate by a heat-resistant adhesive.

According to an embodiment of the present disclosure, after the heat-resistant adhesive is exposed, the connected micro LED array and TFT array may be attached to the flexible substrate by the heat-resistant adhesive. The material of the flexible substrate may comprise cloth or plastic.

Referring to fig. 2a to 2k, fig. 2a to 2k are schematic views of a manufacturing process flow illustrating a method of manufacturing a flexible light emitting device according to one embodiment of the present disclosure. Wherein figure 2i shows the micro LED array 10 and the TFT array 20 attached to a flexible substrate, such as cloth 23. As shown in fig. 2i, after inverting the structure obtained through the operation shown in fig. 2h, the connected micro LED array 10 and TFT array 20 with the UV-curable adhesive 15 and sapphire substrate 14 may be attached to a cloth 23 by a polyimide paste 22.

In step S106, the third substrate may be removed.

According to an embodiment of the present disclosure, after the TFT array connected with the micro LED array is fixed on the flexible substrate, the third substrate and the UV anti-adhesive may be removed. Specifically, the removing the third substrate includes: reducing the viscosity of the UV viscosity-reducing adhesive through a third ultraviolet laser to remove the UV viscosity-reducing adhesive and the sapphire substrate. The wavelength of the third ultraviolet laser is between 350nm and 380 nm.

Referring to fig. 2a to 2k, fig. 2a to 2k are schematic views of a manufacturing process flow illustrating a method of manufacturing a flexible light emitting device according to one embodiment of the present disclosure. Wherein fig. 2j shows the micro LED array 10 and the TFT array 20 fixed on the cloth 23 when the sapphire substrate 14 and the UV deghost 15 of the micro LED array 10 are removed. As shown in fig. 2j, the UV detackifying adhesive 15 may be detackified by a third ultraviolet laser 33 through the sapphire substrate 14 so that the UV detackifying adhesive 15 and the sapphire substrate 14 may be removed. The wavelength of the third ultraviolet laser 33 may be between 350nm and 380nm in order to penetrate the sapphire substrate 14 and reduce the viscosity of the UV detackifying glue 15. An ultraviolet laser having a wavelength between 350nm and 380nm is more favorable to pass through the sapphire substrate 14 and reduce the viscosity of the UV detackifying adhesive 15. It should be noted that the third ultraviolet laser 33 is represented by three lines with arrows in the drawing and the irradiation direction is inclined, which is merely a schematic representation of the third ultraviolet laser and does not limit the coverage and direction of the third ultraviolet laser.

After removing the third substrate and the UV-detackifying glue the flexible light emitting device preparation is completed and fig. 2k shows the prepared flexible light emitting device 1.

According to the embodiment of the present disclosure, in the above method for manufacturing a flexible light emitting device, when two substrates or base plates exist simultaneously, the two substrates or base plates are different and the removal methods are different and do not interfere with each other, that is, when one substrate or base plate is removed, the other substrate or base plate is not affected. Therefore, the first adhesive paste and the temporary substrate (silicon wafer base plate) can be replaced by the heat-resistant paste and the second substrate (glass substrate), and the method of removing the substrates is replaced accordingly. Further, when the material of the flexible base plate is not dissolved in the acetone solution, the second adhesive paste (UV-detackifying paste) and the third substrate (sapphire substrate) may be exchanged with the first adhesive paste and the temporary substrate (silicon wafer substrate), and the method of removing the substrate is exchanged accordingly. Of course, the first adhesive and the temporary substrate and the second adhesive and the third substrate may have more choices in following the above principle, and are not limited herein.

According to another embodiment of the present disclosure, after removing the third substrate, the method may further include: and packaging the LED array and the TFT array which are connected together by arranging a flexible packaging layer. Wherein the flexible encapsulation layer may comprise an encapsulation glue.

In this embodiment, an encapsulation adhesive may be provided on the structure shown in fig. 2k, which may be adhered only on the periphery of the structure shown in fig. 2k or in contact with the shape matching of the structure shown in fig. 2 k. Thereby forming the flexible light emitting device after encapsulation so that the flexible light emitting device can be better protected.

According to the technical scheme of the disclosure, the micro LED array directly epitaxially grows on the first substrate (e.g., sapphire substrate), and when the first substrate is removed, the micro LED array is fixed on a rigid temporary substrate (e.g., a silicon wafer substrate), so that when the micro LED array has a stable rigid temporary substrate, the first substrate (e.g., sapphire substrate) is directly peeled off by ultraviolet laser, so that the first substrate (e.g., sapphire substrate) is not easy to break, and thus the peeling of the first substrate (e.g., sapphire substrate) is more smooth and reliable. Moreover, after the micro LED array is replaced by a third substrate (such as a sapphire substrate) and a second sticky adhesive (such as a UV (ultraviolet) anti-adhesive), the third substrate (such as the sapphire substrate) and the second sticky adhesive (such as the UV anti-adhesive) can be conveniently removed after the connected micro LED array and the TFT array are integrally fixed on the flexible substrate through the heat-resistant adhesive, the heat-resistant adhesive is not easily damaged, and the micro LED array and the TFT array are integrally and reliably fixed on the flexible substrate. If the substrate of the micro LED array is not replaced, but the micro LED array with the first substrate (e.g. sapphire substrate) and the TFT array are directly flip-chip bonded, then finally, when the first substrate is removed, since the integrated micro LED array and TFT array are fixed on the unstable flexible substrate, the first substrate is easily broken when the first substrate is removed by the ultraviolet laser, which is not beneficial to the integrated removal of the first substrate.

In addition, the miniature LED array is replaced by the substrate which is easy to remove after being transferred twice and is connected with the TFT array for driving the miniature LED array, and then the miniature LED array and the TFT array which are fixedly connected together are adhered to the flexible substrate through heat-resistant glue, so that the miniature LED array and the TFT array can be integrally, reliably and efficiently fixed on various flexible substrates, and the flexible light-emitting device can be applied to various flexible products to realize different functions.

The present disclosure also provides a flexible light emitting device. The flexible light emitting device can be manufactured by the manufacturing method of the flexible light emitting device.

Fig. 2k shows a flexible light emitting device 1 of the present disclosure, which flexible light emitting device 1 may comprise, as shown in fig. 2 a-2 k: a flexible substrate; a heat-resistant adhesive disposed on the flexible substrate; a TFT array 20 disposed on the heat resistant glue, and electrodes of the TFT array 20 are on a side of the TFT array 20 away from the heat resistant glue; a micro LED array 10 disposed on the TFT array 20, and an electrode of the micro LED array 10 is connected to an electrode of the TFT array 20.

According to this disclosed flexible light emitting device's structure, it is fixed with the flexible substrate with miniature LED array and TFT array that will link together through heat-resistant glue for miniature LED array and TFT array can be wholly reliably and high-efficiently fixed in on various flexible substrates, thereby make flexible light emitting device can be applied to various flexible products, realize different functions.

Embodiments of the flexible light emitting device of the present disclosure are further described below in conjunction with fig. 2 a-2 k.

According to an embodiment of the present disclosure, the flexible substrate includes cloth or plastic. The flexible substrate may be a cloth 23. As described in the above-described method of manufacturing a flexible light emitting device, the flexible light emitting device 1 may be manufactured on the cloth 23. Likewise, flexible light emitting devices can be fabricated on plastic. Of course, the flexible substrate may also include other flexible targets, and is not limited herein. Thereby, the application of the flexible light emitting device 1 is more extensive.

According to an embodiment of the present disclosure, the heat resistant glue includes a polyimide glue 22. The polyimide paste 22 facilitates the fabrication of TFT arrays thereon. The heat resistant glue may also be any other glue that is resistant to high temperatures and suitable for the fabrication of TFT arrays thereon.

According to an embodiment of the present disclosure, the polyimide glue 22 may be formed by curing a polyimide glue. The polyimide glue fixes the flexible substrate and the TFT array together. The polyimide paste 22 may adhere the cloth 23 and the TFT array 20 together, i.e., adhere the TFT array 20 to the cloth 23. Due to the polyimide glue, the flexible light-emitting device 1 can be prepared on flexible materials such as cloth, and the application range of the flexible light-emitting device is enlarged.

According to the embodiment of the disclosure, the TFT array is prepared on the heat-resistant glue, and the drain electrode of the TFT array is arranged on one side of the TFT array, which is far away from the heat-resistant glue. Taking the polyimide adhesive as an example, since the heat resistant temperature of the polyimide adhesive 22 can reach 300 degrees celsius, the TFT array 20 can be directly prepared on the polyimide adhesive 22 and the drain 2011 of the TFT array 20 is located at the top, so that the manufacturing process can be simplified, and the TFT array 20 is simply and directly fixed on the flexible substrate, such as the fabric 23, by using the polyimide adhesive 22.

According to the embodiment of the disclosure, the micro LED array is prepared on a sapphire substrate, and the cathode of the micro LED array is on the side of the micro LED array far away from the sapphire substrate. The micro LED array 10 may be fabricated on a sapphire substrate with the cathode 1011 of the micro LED array 10 on top.

According to an embodiment of the present disclosure, the micro LED array is connected with the TFT array by flip chip bonding. Specifically, the cathode of the micro LED array is bonded to the drain of the TFT array by flip chip bonding. In this embodiment, the top cathode 1011 of the micro LED array 10 and the top drain 2011 of the TFT array 20 may be bonded by flip chip bonding.

According to an embodiment of the present disclosure, the flexible light emitting device comprises a flexible encapsulation layer encapsulating the flexible light emitting device and comprising a flexible glue. In this embodiment, the encapsulation glue may be applied only at the periphery of the structure shown in fig. 2k or in contact with a shape matching the structure shown in fig. 2 k. Thereby forming the flexible light emitting device after encapsulation so that the flexible light emitting device can be better protected.

It is to be noted that any relevant description (including but not limited to technical features and their roles, explanations, etc.) regarding the structure of the flexible light-emitting device in the above-described method for manufacturing a flexible light-emitting device can be applied to the flexible light-emitting device of the present disclosure.

The present disclosure also provides a light emitting device. The light emitting apparatus includes the above-described flexible light emitting device and a control circuit connected to the flexible light emitting device, and thus can constitute a flexible light emitting apparatus.

According to an embodiment of the present disclosure, the flexible light emitting device may be used as a display device or a lighting device or the like. The micro LED array of the flexible light emitting device can be used as a pixel unit array or a light emitting unit array.

It is noted that the flexible light emitting device can be applied to different flexible products, and the flexible products or flexible parts of the flexible products are prepared on the flexible products as flexible substrates.

In one embodiment, for a garment, the flexible light emitting device may be made directly on the fabric using the fabric of the garment as a flexible substrate, and then the garment is made using the fabric with the flexible light emitting device, or the flexible light emitting device is made directly on the finished garment. Further, the control circuit may be a separate IC chip provided on an FPC (flexible printed circuit) connector, which may also be provided on the cloth, whereby the control circuit may be connected with the flexible light emitting device through the FPC connector. Of course, the FPC connector may be fixed to a device outside the garment to connect with the flexible light emitting device. Thus, a display device or a lighting device including the flexible light-emitting device and the control circuit can be provided on the garment.

In another embodiment, for a beauty mask or face mask (made of plastic), the flexible light-emitting device can be prepared by using the mask or face mask as a flexible substrate and directly arranging the flexible light-emitting device on the side, facing the human face, of the mask or face mask. Further, the control circuit may be a separate IC chip provided on an FPC (flexible printed circuit) connector, which may also be provided on the mask or the face mask, whereby the control circuit may be connected with the flexible light emitting device through the FPC connector. Of course, the FPC connector may be fixed to a device outside the mask or the face mask to connect with the flexible light emitting device. Thus, a light-emitting device including a flexible light-emitting device and a control circuit can be provided on the mask or the face mask. Due to the characteristics of the micro LED array, the light-emitting device can be used for beautifying different areas of a human face by using light with different colors and different intensities.

Of course, the flexible light-emitting device of the present disclosure, when used as a display device, may be a display screen applied to an electronic apparatus. The electronic device may include: any equipment with a display screen, such as a smart phone, a smart watch, a notebook computer, a tablet computer, a vehicle event data recorder, a navigator and the like.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure, and various modifications and changes may be made to the present disclosure by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A method of making a flexible light emitting device, wherein the method comprises:

providing a micro LED array prepared on a first substrate and providing a TFT array prepared on a heat-resistant glue arranged on a second substrate, wherein the heat-resistant glue comprises polyimide glue; the miniature LED array comprises an exposed cathode, the TFT array comprises an exposed drain electrode, the miniature LED array with a first substrate is turned over to enable the exposed cathode of the miniature LED array to face a first adhesive glue, pressure is applied to the miniature LED array through the first substrate, the exposed cathode of the miniature LED array is attached to a temporary substrate through the first adhesive glue, a part of a semiconductor layer at the joint of the miniature LED array and the first substrate is decomposed through first ultraviolet laser to peel off the first substrate, and the opposite part of the cathode of the miniature LED array is fixed on a third substrate through a second adhesive glue; dissolve through acetone solution first stickness is glued, gets rid of first stickness glue with interim substrate, and expose the negative pole of miniature LED array will through the flip-chip bonding the negative pole of miniature LED array is connected with the drain electrode bonding of the TFT array that is equipped with the second substrate that the polyimide glued, melts through second ultraviolet laser polyimide glues, in order to get rid of the second substrate exposes the polyimide glues, will link together through heat-resistant glue miniature LED array with the TFT array is fixed on flexible substrate, makes through third ultraviolet laser the reduction stickness is glued to the second stickness to get rid of second stickness glue and third substrate.

2. The method of manufacturing a flexible light emitting device according to claim 1, wherein after removing the third substrate, the method further comprises:

and packaging the LED array and the TFT array which are connected together by arranging a flexible packaging layer.

3. The method of claim 2, wherein the flexible encapsulation layer comprises an encapsulation glue.

4. The method of claim 1, wherein the material of the flexible substrate comprises a cloth or a mask or a veil.

5. The method of manufacturing a flexible light-emitting device according to claim 1, wherein the first substrate comprises a sapphire substrate.

6. The method of claim 5, wherein the removing the first substrate to expose a cathode-opposing portion of the micro LED array opposite the cathode comprises:

and decomposing a part of the semiconductor layer of the micro LED array at the joint with the sapphire substrate by using first ultraviolet laser so as to strip the sapphire substrate and expose the rest part of the semiconductor layer.

7. The method of claim 1, wherein the semiconductor layer is a GaN layer and the first ultraviolet laser has a wavelength of 257nm.

8. The method of claim 1, wherein the temporary substrate comprises a silicon wafer substrate or a copper substrate.

9. The method of claim 1, wherein the second substrate comprises a glass substrate, a sapphire substrate, or a quartz substrate.

10. The method of claim 1, wherein the second ultraviolet laser has a wavelength of 308nm.

11. The method for manufacturing a flexible light-emitting device according to claim 1, wherein the third substrate comprises a sapphire substrate, a glass substrate or a quartz substrate, and the second adhesive glue comprises a UV (ultraviolet) anti-adhesive glue.

12. The method of claim 1, wherein the third ultraviolet laser has a wavelength between 350nm and 380 nm.