CN108573660B

CN108573660B - Display device

Info

Publication number: CN108573660B
Application number: CN201711035149.3A
Authority: CN
Inventors: 张俊仪; 陈立宜
Original assignee: Mikro Mesa Technology Co Ltd
Current assignee: Mikro Mesa Technology Co Ltd
Priority date: 2017-03-12
Filing date: 2017-10-30
Publication date: 2021-04-09
Anticipated expiration: 2037-10-30
Also published as: CN108573991B; CN108573660A; CN108573991A

Abstract

The invention discloses a display device which comprises an array substrate, at least two lower conducting circuits, at least four micro light-emitting elements, at least four conducting layers, at least two upper conducting circuits and at least one filling material. The lower conductive circuit is arranged on the array substrate. The conductive layers are respectively arranged between the lower conductive circuit and the micro light-emitting element. The upper conductive circuit and the lower conductive circuit are intersected with the micro light-emitting element. Each micro light-emitting element is arranged between at least one of the lower conductive lines and at least one of the upper conductive lines. The filling material is arranged on the array substrate and is provided with at least four openings. The openings respectively expose the micro light-emitting elements. The upper conductive circuits are electrically connected to the micro light-emitting elements through the openings respectively, and the openings of the filling material are substantially aligned with the conductive layers respectively. Therefore, the opening of the filling material is substantially aligned with a corresponding one of the micro light-emitting elements on the conductive adhesive layer, so that the cost for manufacturing a photomask is saved.

Description

Display device

Technical Field

The present invention relates to a display device, and more particularly, to a method for manufacturing a display device.

Background

In recent years, Light Emitting Diodes (LEDs) have become popular for general lighting as well as commercial lighting applications. As a light source, the light emitting diode has many advantages such as low power consumption, long service life, small volume, and fast switching, so that the illumination of the incandescent lamp and the like is gradually replaced by the light emitting diode. The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Disclosure of Invention

It is an object of the present invention to provide a display device in which the openings of the fill material are substantially aligned with corresponding ones of the micro-light emitting elements on the conductive adhesive layer, thereby eliminating the cost of fabricating a mask.

According to an embodiment of the present invention, a display device includes an array substrate, at least two lower conductive traces, at least four micro light emitting devices, at least four conductive traces, at least two upper conductive traces, and at least one filling material. The lower conductive circuit is arranged on the array substrate. The conductive layers are respectively arranged between the lower conductive circuit and the micro light-emitting element. The upper conductive circuit and the lower conductive circuit are intersected with the micro light-emitting element. Each micro light-emitting element is arranged between at least one of the lower conductive lines and at least one of the upper conductive lines. The filling material is arranged on the array substrate and is provided with at least four openings. The openings of the filling material expose the micro light-emitting elements, respectively. The upper conductive circuits are electrically connected to the micro light-emitting elements through the openings of the filling material, and the openings of the filling material are substantially aligned with the conductive layers.

In one or more embodiments of the present invention, at least one of the plurality of micro light emitting elements has an active layer therein. At least one of the plurality of conductive layers is a reflective layer. The reflective layer is disposed between the active layer and a corresponding one of the plurality of lower conductive traces.

In one or more embodiments of the present invention, the display device further includes at least one conductive adhesive layer. The conductive adhesive layer is disposed between at least one of the plurality of lower conductive traces and at least one of the plurality of micro light emitting elements. At least one of the plurality of conductive layers is a bonding layer disposed between the conductive adhesive layer and a corresponding one of the plurality of micro light-emitting elements.

In one or more embodiments of the present invention, at least one of the plurality of micro light-emitting elements has a bonding layer. The bonding layer is adjacent to a corresponding one of the plurality of lower conductive traces. At least one of the plurality of conductive layers is a conductive adhesive layer. The conductive adhesive layer is disposed between the bonding layer and a corresponding one of the plurality of lower conductive traces.

In one or more embodiments of the present invention, the array substrate is flexible.

In one or more embodiments of the present invention, at least one of the plurality of micro light emitting elements is a vertical micro light emitting diode.

In one or more embodiments of the present invention, a material of at least one of the plurality of upper conductive lines is a transparent conductive material.

In one or more embodiments of the invention, the filler material has a refractive index between about 1.5 and about 2.5.

In one or more embodiments of the invention, the packing material has at least four discrete locations. The plurality of openings of the filling material are respectively disposed in the plurality of separation portions.

In one or more embodiments of the present invention, the display device further includes at least one spacer. The spacer is disposed between the plurality of separation sites.

In one or more embodiments of the present invention, the display device further includes at least one passivation layer. The passivation layer is disposed on the plurality of upper conductive lines.

In one or more embodiments of the present invention, the display device further includes a cover substrate. The cover substrate is disposed on the passivation layer, wherein the cover substrate is flexible.

In one or more embodiments of the invention, the passivation layer has a refractive index between about 1.5 and about 2.5.

In one or more embodiments of the present invention, the plurality of micro light-emitting elements comprises at least one red micro light-emitting element, at least one green micro light-emitting element, at least one blue micro light-emitting element, or any combination of the foregoing.

In one or more embodiments of the present invention, a distance between a surface of the filling material away from the array substrate and a surface of the array substrate close to the filling material is greater than a distance between a surface of each micro light emitting element away from the array substrate and a surface of the array substrate close to the filling material.

In one or more embodiments of the present invention, the plurality of openings of the filling material are substantially aligned with the plurality of conductive layers in one direction, respectively. The direction is perpendicular to the surface of the array substrate.

In one or more embodiments of the invention, at least one of the plurality of conductive layers is non-transparent. The vertical projection profile of at least one of the plurality of conductive layers on the surface of the array substrate is substantially the same as the vertical projection profile of a corresponding one of the plurality of openings of the filling material on the surface of the array substrate.

In one or more embodiments of the present invention, at least one of the conductive adhesive layer and the plurality of conductive layers is non-transparent. A corresponding one of the plurality of openings of the fill material is aligned with the conductive adhesive layer and at least one of the plurality of conductive layers.

In one or more embodiments of the present invention, at least one of the conductive adhesive layer and the plurality of conductive layers is non-transparent. The vertical projection profile of at least one of the conductive adhesive layer and the plurality of conductive layers on the surface of the array substrate is substantially the same as the vertical projection profile of the corresponding one of the plurality of openings of the filling material on the surface of the array substrate.

In one or more embodiments of the present invention, the display device further includes at least one reflective layer. The reflective layer is disposed between a corresponding one of the plurality of micro light-emitting elements and the bonding layer. At least one of the bonding layer and the reflective layer is non-transparent. The profile of the perpendicular projection of the aforementioned at least one of the bonding layer and the reflective layer on the surface of the array substrate is substantially the same as the profile of the perpendicular projection of the corresponding one of the plurality of openings of the filling material on the surface of the array substrate.

According to another embodiment of the present invention, a method for manufacturing a display device includes: forming at least two lower conductive circuits on the array substrate; at least four micro light-emitting elements are respectively arranged on the lower conductive circuit; forming at least one filling material to cover the micro light-emitting elements; forming at least four openings in the filling material by photolithography process, so that the micro light-emitting devices are exposed in the openings of the filling material respectively; and forming at least two upper conductive traces on the fill material. The upper conductive circuit is electrically connected to the micro light-emitting element through the opening of the filling material, and the upper conductive circuit and the lower conductive circuit are intersected with the micro light-emitting element.

According to the foregoing structure configuration, the display device of the present invention includes an array substrate, at least two lower conductive traces, at least four micro light emitting elements, at least four conductive traces, at least two upper conductive traces, and at least one filling material. The openings of the filler material are respectively substantially aligned with the conductive adhesive layers. The self-aligned (self-aligned) opening of the fill material is a manufacturing and structural feature of the present invention, and thus the conductive adhesive layer, bonding layer, reflective layer, or any combination thereof of the display device can be used as a mask for the fill material in the photolithography process.

Therefore, the opening of the filling material is ensured to be substantially aligned with the corresponding one of the micro light-emitting elements on the conductive adhesive layer, and the cost for manufacturing a photomask is saved.

Drawings

In order to make the aforementioned and other objects, features, and advantages of the present invention comprehensible, embodiments accompanied with figures are described as follows:

fig. 1 is a schematic partial structure diagram of a display device according to some embodiments of the invention.

Fig. 2 depicts a cross-sectional view of the structure of fig. 1 along line 2-2.

Fig. 3A and 3B are cross-sectional views of vertical micro Light Emitting Diodes (LEDs) according to some embodiments of the invention.

Fig. 4A to 4D are schematic vertical projection views of a conductive adhesive layer, a bonding layer, a reflective layer and the combination thereof on a surface of an array substrate according to some embodiments of the invention.

Fig. 5 is a flowchart illustrating a method of manufacturing a display device according to an embodiment of the invention.

Fig. 6A-6J respectively illustrate cross-sectional views of the structure of fig. 2 at different intermediate stages of fabrication according to a fabrication method.

Fig. 7 is a flowchart illustrating a method of manufacturing a display device according to another embodiment of the present invention.

FIGS. 8A-8G are cross-sectional views of the structure of FIG. 2 at various intermediate stages of fabrication, respectively, according to another fabrication method.

Fig. 9 is a flowchart illustrating a method of manufacturing a display device according to still another embodiment of the present invention.

FIGS. 10A-10D are cross-sectional views of the structure of FIG. 2 at various intermediate stages of fabrication, respectively, in accordance with yet another fabrication method.

Detailed Description

The following description will provide many different embodiments or examples for implementing the subject matter of the present invention. Specific examples of components and arrangements are discussed below to simplify the present disclosure. Of course, these descriptions are only partial examples and the present invention is not limited thereto. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, as well as embodiments in which other features may be formed between the first and second features, in which case the first and second features may not be in direct contact. In addition, the present invention may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and configurations discussed.

Spatially relative terms, such as "below," "lower," "upper," and the like, may be used herein for convenience in describing the relationship of one element or feature to another element or feature in the figures. Spatially relative terms are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the figures. That is, when the device is oriented differently than the figures (rotated 90 degrees or at other orientations), the spatially relative terms used herein should be interpreted accordingly.

Please refer to fig. 1 and fig. 2. Fig. 1 is a schematic partial structure diagram of a display device 1 according to some embodiments of the invention. Fig. 2 depicts a cross-sectional view of the structure of fig. 1 along line 2-2. As shown in fig. 1 and fig. 2, the display device 1 includes an array substrate 10, a plurality of lower conductive traces 11, a plurality of micro light emitting elements 12, a plurality of conductive adhesive layers 13, a plurality of upper conductive traces 14, and a filling material 15.

As used herein, the terms "micro" element, "micro" PN diode, or "micro" light emitting diode, etc., refer to descriptive dimensions of some element or structure in accordance with embodiments of the present invention. As used herein, "micro" elements or structures refer to dimensions in the range of about 1 to 100 microns. It should be understood, however, that the invention is not so limited and that certain aspects of these embodiments may be applied to larger or smaller scales.

Please refer back to fig. 1 and fig. 2. The lower conductive traces 11 are disposed on the array substrate 10. In some embodiments, the lower conductive traces 11 are substantially parallel to each other, and each lower conductive trace 11 extends in the direction Y. In some embodiments, the array substrate 10 is flexible, so that the display device 1 is flexible and in a portable form. Further, the micro light emitting elements 12 arranged in a row are connected to the same lower conductive line 11. For example, the material of the lower conductive traces 11 includes a transparent conductive material. The conductive adhesive layers 13 are respectively disposed between the micro light emitting devices 12 and the lower conductive traces 11.

In addition, the upper conductive trace 14 and the lower conductive trace 11 intersect with the micro light emitting device 12. In other words, each of the micro light emitting elements 12 is disposed between a corresponding one of the lower conductive traces 11 and a corresponding one of the upper conductive traces 14. In some embodiments, the upper conductive traces 14 are parallel to each other, and each upper conductive trace 14 extends in the direction X. In some embodiments, the direction X is substantially perpendicular to the direction Y, but the invention is not limited thereto. Furthermore, the micro light emitting elements 12 arranged in a row are connected to the same upper conductive line 14. For example, the material of the upper conductive traces 14 includes a transparent conductive material. Under the above structure configuration, the display device 1 is a passive pixel array display device.

In some embodiments, the micro light-emitting devices 12 include a plurality of red micro light-emitting devices 12a, a plurality of green micro light-emitting devices 12b, a plurality of blue micro light-emitting devices 12c, or any combination thereof, but the invention is not limited thereto.

In some embodiments, the micro light-emitting elements 12 are vertical micro light-emitting diodes (LEDs).

Please refer to fig. 3A and fig. 3B. Fig. 3A and 3B are cross-sectional views respectively illustrating a micro light-emitting device 12 according to some embodiments of the invention. In fig. 3A, the micro light emitting device 12 includes a first semiconductor layer 126, a second semiconductor layer 128, an active layer 120, and a bonding layer 124, wherein the bonding layer 124 is close to a corresponding one of the lower conductive traces 11 (see fig. 2), for example, but the invention is not limited thereto. Preferably, in fig. 3B, the micro light emitting device 12 further includes a reflective layer 122 in addition to the first semiconductor layer 126, the second semiconductor layer 128, the active layer 120, and the bonding layer 124. The reflective layer 122 is disposed between the first semiconductor layer 126 and the bonding layer 124.

Please refer back to fig. 1 to fig. 3B. The filling material 15 is disposed on the array substrate 10 and has a plurality of openings 20. The openings 20 of the filling material 15 respectively expose the micro-light emitting devices 12 (only two openings 20 are shown in fig. 2). In some embodiments, the distance between the surface of the filling material 15 away from the array substrate 10 and the surface 10a of the array substrate 10 close to the filling material 15 is greater than the distance between the surface of each micro light emitting element 12 away from the array substrate 10 and the surface 10a of the array substrate 10. In some embodiments, the filler material 15 has a refractive index between about 1.5 and about 2.5, but the invention is not limited thereto. The upper conductive traces 14 are electrically connected to the micro-light emitting devices 12 through the openings 20 of the filling material 15, respectively. In some embodiments, the openings 20 of the filling material 15 are substantially aligned with the conductive adhesive layer 13, respectively.

Preferably, in some embodiments, the openings 20 of the filling material 15 are substantially aligned with the bonding layers 124 of the micro light emitting elements 12, respectively (see fig. 3A).

Preferably, in some embodiments, the openings 20 of the filling material 15 are substantially aligned with the reflective layers 122 (see fig. 3B) of the micro light-emitting elements 12 in a direction perpendicular to the surface 10a (see fig. 2) of the array substrate 10, respectively. Specifically, the outline of the opening 20 of the filling material 15 is aligned with the entire combination of the conductive adhesive layer 13, the bonding layer 124, and the non-transparent portion of the reflective layer 122. In other words, the entire combination of the conductive adhesive layer 13, the bonding layer 124, and the non-transparent portion of the reflective layer 122 has a vertical projection on the surface 10a of the array substrate 10. The vertical projection profile of the non-transparent portion defines a vertical projection profile of the opening 20 on the surface 10a of the array substrate 10, and is substantially the same as the vertical projection profile of the opening 20.

For example, please refer to fig. 2 and fig. 4A to 4D. Fig. 4A to 4D are schematic vertical projection views respectively illustrating the conductive adhesive layer 13, the bonding layer 124, the reflective layer 122 and the combination thereof on the surface 10a of the array substrate 10 according to some embodiments of the invention. In this embodiment mode, the conductive adhesive layer 13, the bonding layer 124, and the reflective layer 122 are opaque. As shown in fig. 4A to 4D, on the surface 10a of the array substrate 10, the conductive adhesive layer 13 has a first vertical projection 13 ', the bonding layer 124 has a second vertical projection 124 ', and the reflective layer 122 has a third vertical projection 122 '. The first, second and third

perpendicular projections

13 ', 124' and 122 'together superimpose the superimposed perpendicular projection 20'. The profile of the perpendicular projection of the corresponding one of the openings 20 on the surface 10a of the array substrate 10 is substantially the same as the profile of the superimposed perpendicular projection 20'. That is, a corresponding one of the openings 20 is substantially aligned with the conductive adhesive layer 13, the bonding layer 124, and the reflective layer 122.

In some embodiments, the third perpendicular projection 122' of the reflective layer 122 has the largest projected area. Thus, the profile of the superimposed orthogonal projection 20' is defined primarily by the reflective layer 122. The profile of a corresponding one of the openings 20 of the filling material 15 is mainly defined by the reflective layer 122 and has substantially the same profile as the reflective layer 122. That is, a corresponding one of the openings 20 is substantially aligned with the reflective layer 122, but the invention is not limited thereto.

Please refer to fig. 1 to fig. 3B. The display device 1 further comprises a barrier substance 17. The spacer 17 is provided in the filler 15, and partitions the filler 15 into a plurality of separated portions to isolate the micro light-emitting elements 12. The openings 20 open in the separation region, respectively. In some embodiments, the packing material 15 may not have a separation site, and the separator substance 17 may be omitted.

Furthermore, the display device 1 comprises a passivation layer 18. A passivation layer 18 is disposed on the upper conductive lines 14. In some embodiments, passivation layer 18 has a refractive index between about 1.5 and about 2.5, although the invention is not limited thereto.

The display device 1 further comprises a cover substrate 19. A cover substrate 19 is disposed on the passivation layer 18. In some embodiments, the cover substrate 19 is flexible.

Please refer to fig. 5 and fig. 6A to 6J. Fig. 5 is a flowchart illustrating a method of manufacturing the display device 1 according to an embodiment of the invention, wherein the method includes steps S401 to S409. Fig. 6A-6J respectively illustrate cross-sectional views of the structure of fig. 2 at different intermediate stages of fabrication according to a fabrication method.

It should be understood that the steps shown in fig. 6A to 6J are simplified in order to provide a better understanding of the present invention. Accordingly, additional processes may be provided before the steps shown in fig. 6A-6J, between the steps shown in fig. 6A-6J, or after the steps shown in fig. 6A-6J, and some other processes are briefly described herein.

In fig. 5, the method starts in step S401. A plurality of lower conductive traces 11 are formed on the array substrate 10 (see fig. 6A). In some embodiments, the material of the array substrate 10 includes polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), Polycarbonate (PC), or Polyimide (PI), and may be transparent.

In some embodiments, the lower conductive traces 11 are made of a conductive material and serve as an electrode layer, and may include other layered structures therein. The material of the lower conductive traces 11 may include gold (gold), indium (indium), tin (tin), (silver), bismuth (bismuth), lead (lead), gallium (gallium), cadmium (cadmium), any combination thereof, or an alloy thereof. The lower conductive lines 11 may be transparent, for example, Transparent Conductive Oxide (TCO).

The method continues to step S402. The micro light emitting elements 12 are respectively disposed on the lower conductive traces 11 (see fig. 6B). In detail, the micro light emitting devices 12 are disposed on the lower conductive traces 11 through the conductive adhesive layer 13, respectively. In other words, the conductive adhesive layers 13 are disposed on the lower conductive traces 11 respectively and are used to join the micro light emitting devices 12 and the lower conductive traces 11. Specifically, the micro light-emitting elements 12 are picked up and placed on the conductive adhesive layer 13 using a transfer head (not shown). In addition, various types of transfer heads can be used to pick up the micro light emitting devices 12 of the present invention and place them on the conductive adhesive layer 13. For example, the transfer head may apply pressure to the micro-light emitting elements 12 by vacuum, adhesion, magnetic or electrostatic attraction, so that it picks up the micro-light emitting elements 12.

In addition, the conductive adhesive layer 13 is electrically coupled to the lower conductive trace 11 and the micro light emitting device 12. The material of the conductive adhesive layer 13 is a material that can be cured by heat or ultraviolet rays, for example, solder or a conductive adhesive.

In addition, under the structural configuration of the micro light emitting devices 12, the bonding layer 124 (see fig. 3A and 3B) is used to bond the micro light emitting devices 12 and the conductive adhesive layer 13. Specifically, in fig. 3B, the micro light-emitting element 12 further includes a reflective layer 122. The reflective layer 122 of the micro-light-emitting device 12 can reflect the light emitted from the active layer 120, so that the micro-light-emitting device 12 can emit light upwards to increase the light intensity.

In some embodiments, the lower conductive traces 11 may not have the conductive adhesive layer 13, and the micro light-emitting devices 12 are respectively disposed directly on corresponding ones of the lower conductive traces 11.

The method then continues to step S403. The filler 15 covers the micro light-emitting elements 12 (see fig. 6C). Further, the filler 15 is a photoreactive material.

Then, the method continues to step S404. A plurality of openings 20 are formed in the filling material 15 by photolithography (photolithography) process, so that the micro light emitting devices 12 are exposed from the openings 20 (see fig. 6D and 6E), respectively. In detail, the electromagnetic wave 22 irradiates the filling material 15 at least through the array substrate 10 to pattern the opening 20 in the filling material 15 in a subsequent process. Therefore, the filling material 15 is patterned using the conductive adhesive layer 13 as a mask, and the material of the conductive adhesive layer 13 is a material that can reflect the electromagnetic wave 22. Next, the opening 20 is patterned in the filling material 15 by an exposure process and a development process. Thus, openings 20 are formed in the fill material 15 to expose the micro-light emitting elements 12.

Thereby, the openings 20 of the filling material 15 are substantially aligned with the conductive adhesive layers 13, respectively. The self-aligned opening 20 is a manufacturing and structural feature of the present invention, and thus the conductive adhesive layer 13 of the display device 1 is used as a mask for the filling material 15 in the photolithography process, thereby eliminating the cost of manufacturing the mask.

In some embodiments, the conductive adhesive layer 13 may be a transparent conductive layer. Preferably, the conductive adhesive layer 13 may be omitted from the configuration. In the foregoing case, the opening 20 is patterned in the filling material 15, and when the electromagnetic wave 22 irradiates the filling material 15 through at least the array substrate 10, the filling material 15 can be patterned by using the bonding layer 124 as a mask. In some embodiments, the bonding layer 124 is made of a material that reflects the electromagnetic wave 22. Accordingly, the openings 20 are formed in the filling material 15 by photolithography, so that the micro light emitting devices 12 are respectively exposed from the openings 20. The openings 20 of the filler material 15 are substantially aligned with the bonding layers 124, respectively.

In some embodiments, when the micro light emitting devices 12 shown in fig. 3B are disposed on the lower conductive traces 11, the conductive adhesive layer 13 and the bonding layer 124 may be transparent conductive layers. Preferably, one of the conductive adhesive layer 13 and the bonding layer 124 may be omitted from the configuration, and the other of the conductive adhesive layer 13 and the bonding layer 124 may be a transparent conductive layer. In the aforementioned case, the opening 20 is patterned in the filling material 15, and when the electromagnetic wave 22 irradiates the filling material 15 at least through the array substrate 10, the filling material 15 can be patterned by using the reflective layer 122 as a mask. In some embodiments, the reflective layer 122 is made of a material that reflects the electromagnetic wave 22. Accordingly, the openings 20 are formed in the filling material 15 by photolithography, so that the micro light emitting devices 12 are respectively exposed from the openings 20. The openings 20 of the filling material 15 are substantially aligned with the reflective layers 122, respectively. In some embodiments, the conductive adhesive layer 13, the bonding layer 124, and the reflective layer 122 are non-transparent. Thus, the opening 20 of the filling material 15 is substantially aligned with the entire combination of the conductive adhesive layer 13, the bonding layer 124, and the reflective layer 122. In other words, referring to fig. 4A to 4D, the profile of the corresponding one of the openings 20 of the filling material 15 is substantially the same as the profile of the superimposed vertical projection 20 ', and the profile of the superimposed vertical projection 20 ' is superimposed by the conductive adhesive layer 13, the bonding layer 124 and the first, second and third

vertical projections

13 ', 124 ' and 122 ' of the reflective layer 122.

Then, the method continues to step S405. A plurality of separation sites are formed in the filling material 15 by patterning grooves, and openings 20 are opened in the separation sites, respectively (refer to fig. 6F). The grooves 150 are patterned in the filling material 15 by an exposure process and a development process. Thus, the filling material 15 forms a plurality of separation portions, and the openings 20 are formed in the separation portions, respectively.

Then, the method continues to step S406. An isolation material 17 is formed between the patterned filler materials 15 (see fig. 6G). In some embodiments, the material of the isolation material 17 includes a non-transparent resin or air. In some embodiments, the patterned fill material 15 may not have an isolation material 17 disposed therein.

Then, the method continues to step S407. A plurality of upper conductive traces 14 are formed on the fill material 15. The upper conductive traces 14 are electrically connected to the micro light-emitting devices 12 through the openings 20 of the filling material 15, and the upper conductive traces 14 and the lower conductive traces 11 intersect with each other at the micro light-emitting devices 12 (see fig. 6H).

Then, the method continues to step S408. A passivation layer 18 is formed on the upper conductive lines 14, the filling material 15, and the isolation material 17 (see fig. 6I). In some embodiments, the material of passivation layer 18 comprises a curable polymer material or a photoresist material. In some embodiments, the upper conductive lines 14 may not have the passivation layer 18 disposed thereon.

Then, the method continues to step S409. The cover substrate 19 is disposed on the passivation layer 18 (see fig. 6J). The material of the cover substrate 19 includes polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), Polycarbonate (PC), Polyimide (PI), or any combination of the foregoing materials.

Please refer to fig. 7 and fig. 8A to 8G. Fig. 7 is a flowchart illustrating a method of manufacturing the display device 1 according to another embodiment of the invention, wherein the method includes steps S601-S607. FIGS. 8A-8G are cross-sectional views of the structure of FIG. 2 at various intermediate stages of fabrication, respectively, according to another fabrication method.

It should be noted that steps S601, S602, and S604-S607 in this embodiment are substantially the same as steps S401, S402, and S406-S409 shown in fig. 5, respectively, and the structure, function, and connection between these elements can refer to the related description, and are not repeated herein. It is to be noted here that the present embodiment differs from the embodiment shown in fig. 5 in that the step of forming the upper filling material 15 and the opening 20 is modified.

Specifically, in step S603 of fig. 7, a plurality of separated portions of the filling material 15 are deposited on the array substrate 10 and surround the micro light-emitting devices 12 through various suitable processes. Examples of the foregoing processes may include screen printing or ink jet printing. A plurality of openings 20 are formed in the separation portions of the filler 15, and the openings 20 are opened in the separation portions, respectively (see fig. 8C).

Thus, with the foregoing configuration, the filling material 15 is formed around the micro light-emitting elements 12 in discrete locations, and the openings 20 are formed. The micro light-emitting elements 12 are exposed to the openings 20, respectively.

Please refer to fig. 9 and fig. 10A to 10D. FIG. 9 is a flowchart illustrating a method for manufacturing the display device 1 according to still another embodiment of the present invention, wherein the method comprises steps S801-S809. FIGS. 10A-10D are cross-sectional views of the structure of FIG. 2 at various intermediate stages of fabrication, respectively, in accordance with yet another fabrication method.

It should be noted that steps S801 to S806 in this embodiment are substantially the same as steps S401 to S406 shown in fig. 5, and the structure, function and connection between these elements can refer to the related description, and are not repeated herein. It is to be noted here that the present embodiment differs from the embodiment shown in fig. 5 in that the steps of forming the upper conductive line 14, the passivation layer 18, and the cover substrate 19 are modified.

Specifically, in steps S807 to S809 of fig. 9, the passivation layer 18 is formed on the cover substrate 19. Next, the upper conductive line 14 is formed on the passivation layer 18. In some embodiments, the passivation layer 18 may be omitted from being disposed on the cover substrate 19. That is, the upper conductive line 14 is directly formed on the cover substrate 19 (see fig. 10B and 10C).

The combination of the cover substrate 19, the passivation layer 18 and the upper conductive traces 14 is disposed on the filling material 15, and the upper conductive traces 14 are electrically connected to the micro light-emitting devices 12 through the openings 20. Specifically, the cover substrate 19 is picked up and placed on the filling material 15 and the micro light-emitting elements 12 by a transfer head (not shown) (see fig. 10D).

As is apparent from the above detailed description of the embodiments of the present invention, the display device of the present invention includes an array substrate, a lower conductive line, a micro light emitting device, a four conductive layers, an upper conductive line, and a filling material. The openings of the filler material are respectively substantially aligned with the conductive adhesive layers. The self-aligned (self-aligned) opening of the fill material is a manufacturing and structural feature of the present invention, and thus the conductive adhesive layer, bonding layer, reflective layer, or any combination thereof of the display device can be used as a mask for the fill material in the photolithography process. Therefore, the opening of the filling material is ensured to be substantially aligned with the corresponding one of the micro light-emitting elements on the conductive adhesive layer, and the cost for manufacturing a photomask is saved.

While the features of the various embodiments of the present invention described above will provide those skilled in the art with a better understanding of the various aspects of the present invention, it will be appreciated by those skilled in the art that other embodiments may be utilized and still practice the present invention. Therefore, the spirit and scope of the present invention is not limited to the foregoing embodiments.

The foregoing features of the various embodiments will provide those skilled in the art with a better understanding of various aspects of the present invention, and it is to be understood that those skilled in the art may, upon attaining an understanding of the same objects and/or advantages of the embodiments of the invention described herein, may readily adopt into consideration other processes and structures for further design or modification, and that such equivalent structures may be substituted for, and modified without departing from the spirit and scope of the invention.

Claims

1. A display device, comprising:

an array substrate;

at least two lower conductive circuits arranged on the array substrate;

at least four micro light-emitting elements;

at least four conductive layers respectively arranged between the at least two lower conductive circuits and the at least four micro light-emitting elements;

at least two upper conductive traces intersecting the at least two lower conductive traces at the at least four micro light-emitting elements, wherein each of the micro light-emitting elements is disposed between at least one of the at least two lower conductive traces and at least one of the at least two upper conductive traces;

at least one filling material disposed on the array substrate, having at least four separated portions, and having at least four openings disposed in the at least four separated portions, respectively, the at least four openings exposing the at least four micro light emitting devices, respectively, wherein the at least two upper conductive traces are electrically connected to the at least four micro light emitting devices through the at least four openings, respectively, and the at least four openings of the filling material are substantially aligned with the at least four conductive layers, respectively; and

at least one spacer disposed between the at least four discrete locations, wherein one of the at least two upper conductive traces crosses over opposing sides of the at least one spacer.

2. The display device of claim 1, wherein at least one of the at least four micro light-emitting elements has an active layer therein, and at least one of the at least four conductive layers is a reflective layer disposed between the active layer and a corresponding one of the at least two lower conductive traces.

3. The display device of claim 1, further comprising:

at least one conductive adhesive layer disposed between at least one of the at least two lower conductive traces and at least one of the at least four micro light-emitting elements, wherein at least one of the at least four conductive layers is a bonding layer disposed between the conductive adhesive layer and a corresponding one of the at least four micro light-emitting elements.

4. The display device of claim 1, wherein at least one of the at least four micro light emitting elements has a bonding layer proximate to a corresponding one of the at least two lower conductive traces, wherein at least one of the at least four conductive layers is a conductive adhesive layer disposed between the bonding layer and the corresponding one of the at least two lower conductive traces.

5. The display device of claim 1, wherein the array substrate is flexible.

6. The display device of claim 1, wherein at least one of the at least four micro light-emitting elements is a vertical micro light-emitting diode.

7. The display device according to claim 1, wherein a material of at least one of the at least two upper conductive lines is a transparent conductive material.

8. The display device of claim 1, wherein the fill material has a refractive index between 1.5 and 2.5.

9. The display device of claim 1, further comprising:

at least one passivation layer disposed on the at least two upper conductive lines.

10. The display device of claim 9, further comprising:

and the covering substrate is arranged on the passivation layer, and is flexible.

11. The display device of claim 9, wherein the passivation layer has a refractive index between 1.5 and 2.5.

12. The display device of claim 1, wherein the at least four micro light-emitting elements comprise at least one red micro light-emitting element, at least one green micro light-emitting element, at least one blue micro light-emitting element, or any combination thereof.

13. The display device according to claim 1, wherein a distance between a surface of the filling material away from the array substrate and a surface of the array substrate close to the filling material is greater than a distance between a surface of each of the micro light emitting elements away from the array substrate and a surface of the array substrate close to the filling material.

14. The display device of claim 1, wherein the at least four openings of the filler material are substantially aligned with the at least four conductive layers in a direction, respectively, perpendicular to a surface of the array substrate.

15. The display device of claim 1, wherein at least one of the at least four conductive layers is non-transparent, and a vertical projection profile of the at least one of the at least four conductive layers on the surface of the array substrate is substantially the same as a vertical projection profile of a corresponding one of the at least four openings on the surface of the array substrate.

16. The display device of claim 3, wherein at least one of the conductive adhesive layer and the at least four conductive layers is non-transparent, and a corresponding one of the at least four openings is aligned with the at least one of the conductive adhesive layer and the at least four conductive layers.

17. The display device of claim 3, wherein at least one of the conductive adhesive layer and the at least four conductive layers is non-transparent, and a vertical projection profile of the at least one of the conductive adhesive layer and the at least four conductive layers on the surface of the array substrate is substantially the same as a vertical projection profile of a corresponding one of the at least four openings on the surface of the array substrate.

18. The display device of claim 4, further comprising:

at least one reflective layer disposed between a corresponding one of the at least four micro light emitting elements and the bonding layer, wherein at least one of the bonding layer and the reflective layer is non-transparent, and a profile of a perpendicular projection of the at least one of the bonding layer and the reflective layer on the surface of the array substrate is substantially the same as a profile of a perpendicular projection of a corresponding one of the at least four openings on the surface of the array substrate.