CN212907784U

CN212907784U - Display back plate, display module and huge transfer device

Info

Publication number: CN212907784U
Application number: CN202021720519.4U
Authority: CN
Inventors: 李强; 熊浪
Original assignee: Chongqing Kangjia Photoelectric Technology Research Institute Co Ltd
Current assignee: Chongqing Kangjia Photoelectric Technology Research Institute Co Ltd
Priority date: 2020-08-18
Filing date: 2020-08-18
Publication date: 2021-04-06
Anticipated expiration: 2030-08-18

Abstract

The utility model discloses a show backplate, display module and huge transfer device, through the cooperation of the flexible gas microchannel in through-hole in showing the backplate and the huge transfer device, realized forming suction through the negative pressure in the chip huge transfer manufacturing procedure, improve the chip reliability of debonding from the base plate of keeping in, still realized blowing through the malleation after binding simultaneously, will bind the effectual blow-off of failed chip and show the backplate. In addition, the through holes in the display back plate can also improve the heat dissipation effect in the working state.

Description

Display back plate, display module and huge transfer device

Technical Field

The utility model relates to a Micro LED display device's preparation technique especially relates to and shows backplate, display module to and shift huge amount Micro LED chip to the huge amount transfer device who shows the backplate.

Background

The number of Micro LED chips used in Micro LED display devices is enormous, and thus the transfer of the huge number of Micro LED chips in the fabrication technology of Micro LED display devices belongs to key and difficult technologies.

The preparation method of the current Micro LED display device comprises the following steps: firstly, transferring the MicroLED chip on a growth substrate to a temporary storage substrate by a transfer head or other methods; then, the red, green and blue Micro LED chips are transferred to a display back panel in batches with the aid of precise alignment equipment and are arranged according to a certain rule.

There are many problems with existing such bulk transfer techniques, such as:

1. since the temporary substrate is required to be coated with glue for transfer during the manufacturing process, the chips may be trapped in the glue. Or the conductive adhesive on the display back plate has insufficient adhesion force, so that the conductive adhesive cannot be transferred to the display back plate.

2. In the repair process after the transfer is finished, due to the small size of the chip, the abnormal chip cannot be conveniently removed at present.

3. After the display device is manufactured, the service life of the display device may be affected by the heat dissipation problem in the use process.

Therefore, how to optimally design the display backplane structure and how to design the huge transfer device are one of the key technical problems to be solved.

SUMMERY OF THE UTILITY MODEL

Based on the not enough of above-mentioned prior art, this application provides a show backplate, display module and huge transfer device for go the inconvenient technical problem of the unusual chip of department among the solution prior art.

The utility model provides a display back plate, the upper surface of which is distributed with a huge number of contact electrode groups; each contact electrode group comprises an N-type contact electrode and a P-type contact electrode; at least one through hole is arranged between the N-type contact electrode and the P-type contact electrode in one contact electrode group; the through hole is opposite to the flip LED chip body welded between the N-type contact electrode and the P-type contact electrode; one of the through holes corresponds to at least one flexible gas microchannel on the tray assembly.

The utility model provides a display module, which comprises the display back plate and an inverted LED chip; the flip LED chip is welded on the contact electrode group of the display back plate.

The application also provides a huge transfer device for solving the problems of unreliable chip transfer and the like in the prior art.

The utility model provides a huge transfer device, include: a tray assembly, a gas pipe and a gas pump; the tray assembly comprises a flexible cushion layer, micropores are densely distributed on the flexible cushion layer, and the upper surface of the flexible cushion layer is in surface contact with the lower surface of the display back plate; one section of the gas pipeline is connected with the tray assembly, and the other end of the gas pipeline is connected with the gas pump; the micropores cooperate with the gas pipeline to form flexible gas microchannels, and a through hole on the display back plate corresponds to at least one flexible gas microchannel on the tray assembly.

Above-mentioned show backplate, display module and huge transfer device through the through-hole in showing the backplate and the cooperation of the flexible gas microchannel in the huge transfer device, has realized forming suction through the negative pressure in the chip huge transfer manufacturing procedure, improves the chip and from the reliability of debonding in the base plate of keeping in, has still realized simultaneously and has blown through the malleation after binding, will bind the effectual blowing of chip that fails and show the backplate. In addition, after the through holes on the display back plate are filled with the heat dissipation materials, the heat dissipation effect in the working state can be improved.

Drawings

Fig. 1 is a schematic diagram of a display backplane according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a display device according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a bulk transfer apparatus according to an embodiment of the present invention;

FIG. 4-1 is a schematic diagram of an embodiment of the present invention illustrating a step of transferring a chip to a temporary substrate;

FIG. 4-2 is a schematic diagram of a second step of transferring the chip to the temporary substrate according to an embodiment of the present invention;

FIGS. 4-3 are schematic diagrams of the third step of transferring the chip to the temporary substrate according to the embodiment of the present invention;

FIGS. 4-4 are schematic diagrams illustrating a fourth step of transferring the chip to the temporary substrate according to an embodiment of the present invention;

FIGS. 4-5 are schematic diagrams of the fifth step of transferring the chip to the temporary substrate according to the embodiment of the present invention;

FIGS. 4-6 are schematic diagrams illustrating six steps of transferring a chip to a temporary substrate according to an embodiment of the present invention;

FIG. 5-1 is a schematic diagram of an embodiment of the present invention illustrating a step of transferring a chip to a display backplane;

FIG. 5-2 is a schematic diagram of a second alignment lamination step for transferring the chip to the display backplane according to an embodiment of the present invention;

FIGS. 5-3 are schematic diagrams of a second step of releasing glue for transferring the chip to the display backplane according to an embodiment of the present invention;

FIGS. 5-4 are schematic diagrams illustrating a fourth step of transferring the chip to the display backplane according to an embodiment of the present invention;

fig. 5-5 are schematic diagrams illustrating steps of transferring the chip to the display backplane according to an embodiment of the present invention.

Detailed Description

To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are given in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

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. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

In the prior art, the structural design of the display backplane and the structural design of the bulk transfer device are separated, the performance requirements of the display backplane are mainly considered, and the coordination of the bulk transfer process of the chip is hardly considered, so that the reliability in the bulk transfer cannot be effectively improved.

Based on this, the present application intends to provide a solution to the above technical problem, the details of which will be explained in the following embodiments.

First, the structure of the display backplane according to the embodiment of the present application is described below, and fig. 1 is a front view of the display backplane, in which a chip bonding surface is shown. A huge number of contact electrode groups are distributed on the upper surface of the display back plate; each contact electrode group comprises an N-type contact electrode 5 and a P-type contact electrode 6; it should be noted that the arrangement of the contact electrodes may be horizontal, vertical, or in other directions or in a combination of different directions, and the N-type contact electrode 5 and the P-type contact electrode 6 are provided in pairs, and the positions are not necessarily completely identical. In fig. 1, a relatively common horizontal arrangement is shown, and the N-type contact electrode 5 is located on the left side, and the P-type contact electrode 6 is located on the right side, so that the arrangement is convenient for transferring a large amount of chips.

At least one through hole 4 is arranged between the N-type contact electrode 5 and the P-type contact electrode 6 in one contact electrode group; in fig. 1, only one through hole is shown, and in other embodiments, a plurality of through holes may be provided, and the shape of the through holes is circular in the drawing, and may be oval, square, rectangular, or the like.

The through-hole 4 is disposed opposite to a flip-chip LED chip body (not shown in fig. 1) soldered between the N-type contact electrode 5 and the P-type contact electrode 6, as can be seen with reference to fig. 2. One through hole 4 corresponds to at least one flexible gas microchannel on the tray assembly. The through hole arrangement of the present application is crucial, and has two roles: the display backboard comprises a display backboard, a through hole, a gas flow channel, a display backboard; and secondly, the LED chip can be ejected out of the through hole through the ejector pin so as to be separated from the display back plate, and the LED chip can be generally used for removing the LED chip with problems in the repairing process.

In addition to the consideration of the number, shape, position and size of the through holes, the through holes need to be arranged to bypass the circuit on the display backplane as much as possible, that is, there is a gap between the through holes and the circuit on the display backplane, so as to ensure that the performance of the display backplane is not affected.

The display device of the embodiment of the application, as shown in fig. 2, includes a flip-chip LED chip 8 in addition to the display backplane shown in fig. 1, where the flip-chip LED chip 8 is soldered on the contact electrode group of the display backplane, that is, one pin is soldered on the N-type contact electrode 5 and the other pin is soldered on the P-type contact electrode 6. Only two LED chips 8 are shown soldered to the display backplane, in practice, typically all sets of contact electrodes are soldered with LED chips 8.

The welding mode is that firstly, solder is coated on the contact electrode, and then the pin of the chip is welded on the contact electrode through a binding process.

When the welding of the LED chip 8 on the display back plate meets the requirement of production yield, the through hole on the display back plate can be filled, the filling material can be an insulating heat conduction material to help the display device to dissipate heat, and the insulating material can be heat conduction silicone grease or heat conduction pouring sealant and the like.

As shown in fig. 3, the bulk transfer apparatus according to the embodiment of the present application includes: a tray assembly 1, a gas pipeline 2 and a gas pump 3; the tray assembly comprises a flexible mat 11, a structured layer of closely spaced dots in the figure.

The flexible cushion layer 11 is densely distributed with micropores, and the upper surface of the flexible cushion layer 11 is in surface contact with the lower surface of the display back plate, that is, the chip binding surface of the display back plate faces upward and is flatly placed on the upper surface of the flexible cushion layer to form surface contact.

One end of the gas pipeline 2 is connected with the tray component 1, and the other end is connected with the gas pump 3; the micropores cooperate with the gas pipes 2 to form flexible gas microchannels, and a through hole on one display backplane corresponds to at least one flexible gas microchannel on the tray assembly 1. Like this when air pump 3 is outwards blown, it is gaseous can exert malleation power of blowing to the LED chip through gas piping 2, flexible gaseous microchannel, through-hole 4 on the demonstration backplate, when air pump 3 breathes in, it is gaseous can exert negative pressure suction through-hole 4, flexible gaseous microchannel, the last gas piping 2 of demonstration backplate to the LED chip.

Because will show the backplate and place at flexible bed course 11 and put, air pump 3 needs the negative pressure to breathe in when huge transfer, need the malleation to blow again when binding the preliminary screening of inefficacy, for better fixed demonstration backplate, can also set up the clamping unit on the tray subassembly, will show the backplate and fix on flexible bed course 11 through the clamping unit.

In addition, the flexible cushion layer can be selected from a flexible foaming layer, and particularly can be EPDM flexible foaming sponge.

If do not need to carry out the prescreening to binding the LED chip that became invalid, air pump 3 can be one-way air pump, only need bleed promptly just can, if need carry out the prescreening to binding the LED chip that became invalid, the air pump should be for supplying gas and bleeding two-way air pump.

The process flow of transferring the chip to the temporary substrate according to the embodiment of the present invention is described in detail below, including the following six steps, which are specifically described below.

Step one, as shown in fig. 4-1, the LED chip 40 is attached to the growth substrate 41 in an initial state, the pins 42 of the LED chip 40 are exposed, and the light emitting surface of the LED chip 40 is attached to the growth substrate 41.

Step two, as shown in fig. 4-2, the first temporary storage substrate 44 coated with the first adhesive material 43 is attached to the exposed surface of the leads 42, that is, the first adhesive material 43 is attached to the leads 42.

Step three, as shown in fig. 4-3, the growth substrate 41 is peeled Off by utilizing LLO (Laser Lift Off) technology, and at this time, the LED chip 40 is successfully transferred onto the first temporary storage substrate 44. The black dashed bars in the figure are shown to indicate the positions of LLO technique peeling.

Step four, as shown in fig. 4-4, because black gallium metal remains after the growth substrate 41 is stripped by the laser, the black gallium metal may be cleaned by diluted hydrochloric acid, or cleaned by other cleaning materials, or cleaned by other processes. If no residue remains after the growth substrate 41 is peeled off, cleaning is not necessary. The arrows in the figure indicate the regions washed with diluted hydrochloric acid.

Step five, as shown in fig. 4-5, the light emitting surface of the LED chip 40 on the first temporary storage substrate 44 is attached to the second temporary storage substrate 46 coated with the second adhesive material 45.

Step six, as shown in fig. 4-6, the first adhesive material 43 is debonded, and at this time, the operation process of transferring the chip to the temporary storage substrate is completed. At this time, the LED chip 40 fixed on the second temporary substrate 46 is obtained, and the leads 42 of the LED chip 40 are exposed. The arrows in the figure indicate the disperging operation.

The first adhesive material 43 and the second adhesive material 45 on the first temporary substrate 44 and the second temporary substrate 46 may be photo-decomposed or thermal-decomposed, and the decomposition method may use light or heat correspondingly.

In addition to the above process of transferring the chip to the temporary storage substrate, other process methods may be adopted to transfer the chip to the temporary storage substrate, the application is not limited to the above process, and after the chip is transferred to the temporary storage substrate, the following process methods may be adopted to further transfer the chip to the display backplane, including six steps, which will be described in detail below.

Step one, as shown in fig. 5-1, applying solder 53, which may be conductive adhesive or other soldering material, on the contact electrode 52 of the display back plate 51, and placing the display back plate 51 on the tray assembly 54;

step two, as shown in fig. 5-2, the air pump 55 is turned on, and the air pump 55 generates a negative pressure, that is, the air pump 55 sucks air, and the second temporary storage substrate 46 and the display back plate 51 are aligned and then attached. As shown in fig. 5-3, the second adhesive material 45 on the second temporary substrate 46 is debonded by laser or heat, and since the suction force of the negative pressure and the adhesion force of the conductive adhesive are greater than the adhesion force of the LED chip 40 and the second adhesive material 45, the LED chip 40 is successfully transferred to the display back plate 51. The arrows in the figure indicate the gas flow direction.

And step three, taking out all the transferred display back plates, and performing binding operation on the display back plates, wherein the binding operation can be performed in a laser or heating mode. This step can be processed by existing process steps, which are not shown.

Step four, as shown in fig. 5-4, the display back plate 51 which is bound is placed on the tray component 54 again, the air pump 55 is started to blow air, so that positive pressure is generated, the LED chips 40 which are bound in failure are blown away from the display back plate 51 under the positive pressure, and the LED chips 40 which are transferred are primarily screened in this step; the arrows in the figure indicate the gas flow direction.

Step five, as shown in fig. 5-5, the preliminarily screened display back plate 51 is subjected to energization detection, if the abnormal LED chip 40 is confirmed, the abnormal LED chip is required to be removed, the method can be that the LED chip 40 required to be removed is heated by laser, so that the conductive adhesive 53 on the lower portion of the LED chip is melted, some adhesive force still exists after the conductive adhesive 53 is melted, the LED chip can be jacked up by a thimble 56 through a through hole 56 of the display back plate 51, and a device similar to a dust collector can be additionally arranged after jacking to suck the abnormal LED chip away.

And sixthly, transferring the missing position of the chip on the display back panel again until the display back panel meets the requirement of production yield, and finally filling the through hole in the display back panel, wherein the filling material can be insulating heat conduction material to help the display device to dissipate heat, and the insulating material can be heat conduction silicone grease or heat conduction pouring sealant and the like.

It is to be understood that the invention is not limited to the above-described embodiments, and that modifications and variations may be made by those skilled in the art in light of the above teachings, and all such modifications and variations are intended to be included within the scope of the invention as defined in the appended claims.

Claims

1. A display back plate is characterized in that a huge number of contact electrode groups are distributed on the upper surface of the display back plate; each contact electrode group comprises an N-type contact electrode and a P-type contact electrode; at least one through hole is arranged between the N-type contact electrode and the P-type contact electrode in one contact electrode group; the through hole is opposite to the flip LED chip body welded between the N-type contact electrode and the P-type contact electrode; one of the through holes corresponds to at least one flexible gas microchannel on the tray assembly.

2. The display backplane of claim 1, wherein one through hole is disposed for each of the sets of contact electrodes.

3. The display backplane of claim 1, wherein the through-hole is shaped as one of: circular, square, oval and rectangular.

4. A display backplane according to any of claims 1-3, wherein the through holes are spaced from the circuitry on the display backplane.

5. A display module comprising the display backplane of any of claims 1-4, and a flip-chip LED chip; the flip LED chip is welded on the contact electrode group of the display back plate.

6. The display module of claim 5, wherein the through-holes are filled with an insulating and thermally conductive material.

7. A bulk transfer apparatus, the apparatus comprising: a tray assembly, a gas pipe and a gas pump; the tray assembly comprises a flexible cushion layer, micropores are densely distributed on the flexible cushion layer, and the upper surface of the flexible cushion layer is in surface contact with the lower surface of the display back plate; one end of the gas pipeline is connected with the tray assembly, and the other end of the gas pipeline is connected with the gas pump; the micropores cooperate with the gas pipeline to form flexible gas microchannels, and a through hole on the display back plate corresponds to at least one flexible gas microchannel on the tray assembly.

8. The bulk transfer device of claim 7, wherein the tray assembly further comprises a clamping unit for securing the display backplane on the flexible cushion.

9. The bulk transfer device of claim 7, wherein the flexible cushion layer is a flexible foam layer.

10. The mass transfer device of any one of claims 7-9, wherein said air pump is a bidirectional air pump for supplying and evacuating air.