METHOD FOR EFFICIENT MANUFACTURE OF DISPLAY PANEL

A method for efficient manufacture of a color or monochrome display panel by an masse transfer of a large number of light emitting elements includes providing crystal blocks, providing a driving substrate, transferring the crystal blocks to the driving substrate, patterning the crystal blocks, and applying wavelength-converting elements to each light source, for a monochrome or color display device.

FIELD

The subject matter herein generally relates to displays and particularly relates to a method for making a display panel.

BACKGROUND

The sizes of light emitting elements such as light emitting diodes (LEDs) are always tending towards smaller size, as a result, efficiently transferring a large number of light emitting elements to a target substrate is challenging.

Therefore, there is room for improvement in the art.

DETAILED DESCRIPTION

The term “comprising” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, group, series, and the like. The disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references can mean “at least one”.

Referring toFIG. 1, a flow chart of a method for making a display panel is disclosed. The method is provided by way of embodiment, as there are a variety of ways to carry out the method. The method described below can be carried out using the configurations illustrated inFIGS. 2 through 10for example, and various elements of these figures are referenced in explaining the method. Each block shown inFIG. 1represents one or more processes, methods, or subroutines, carried out in the method. Additionally, the illustrated order of blocks is by example only and the order of the blocks can change. The method can begin at Block S1.

Block S1: a plurality of crystal blocks30is provided.

As shown inFIG. 2, the crystal blocks30are spaced apart from each other on a substrate10. The substrate10may be a growth substrate of the crystal blocks30, and a material of the substrate10may be sapphire, quartz, or the like.

As shown inFIG. 3, the Block S1further includes providing the substrate10, forming a release layer20on the substrate10, and forming the crystal blocks30to be spaced apart from each other on a surface of the release layer20away from the substrate10. Each of the crystal blocks30includes a first electrode layer31, a P-type doped phosphor layer34, an active layer33, an N-type doped phosphor layer32, and a second electrode layer35arranged in that order.

In one embodiment, the release layer20may be an adhesive layer of a type of colloid that decomposes and loses its viscosity under laser irradiation, ultraviolet irradiation, or heating. The P-type doped phosphor layer34is, for example, a P-type gallium nitride layer. The active layer33is, for example, a multiple quantum well layer. The N-type doped phosphor layer32is, for example, an N-type gallium nitride layer.

As shown inFIG. 4, the driving substrate50defines a plurality of receiving areas50a. Each of the receiving areas50ais configured for receiving one of the crystal blocks30. As shown inFIG. 5, each of the receiving areas50adefines a plurality of conductive blocks53spaced apart from each other.

In one embodiment, the driving substrate50is a thin film transistor substrate. The driving substrate50includes a base layer51, a driving circuit layer52(e.g., a thin film transistor array layer) on the base layer51and the conductive blocks53one a side of the driving circuit layer52away from the base layer51. Each of the conductive blocks53is electrically connected to the driving circuit layer52.

In one embodiment, the base layer51may be made of a rigid material, such as glass, quartz, silicon wafer, or the like. In other embodiments, the base layer51may be made of a flexible material, such as polyimide (PI) or polyethylene terephthalate (PET).

Block S3: the crystal blocks30are transferred to the driving substrate50.

In one embodiment, the release layer20is processed by laser irradiation, ultraviolet irradiation, or heating, so that each of the crystal blocks30is transferred to one of the receiving areas50a.

As shown inFIG. 6, in step S3, one of the crystal blocks30is transferred to one of the receiving areas50aof the driving substrate50each time.

In one embodiment, the positioning and size of each receiving area50aon the driving substrate50are compatible with the positioning and size of each crystal block30on the substrate10. In step S3, more than one crystal block30can be transferred to the driving substrate50each time.

As shown inFIG. 7, after each of the crystal blocks30is transferred onto one receiving area50a, the first electrode layer31covers all the conductive blocks53in the receiving area50a. There is a gap between two adjacent conductive blocks53.

Block S4: each of the crystal blocks30is patterned.

As shown inFIG. 8, the first electrode layer31, the P-type doped phosphor layer34, the active layer33, the N-type doped phosphor layer32, and the second electrode layer35are all patterned. Each of the crystal blocks30is patterned to form a plurality of spaced light emitting elements40. Each of the light emitting elements40includes the patterned first electrode layer31, the patterned P-type doped phosphor layer34, the patterned active layer33, the patterned N-type doped phosphor layer32, and the patterned second electrode layer35.

Each of the light emitting elements40is on one of the conductive blocks53and is electrically connected to the one of the conductive blocks53through the first electrode layer31. That is, each of the light emitting elements40is electrically connected to the driving circuit layer52through one of the conductive blocks53.

In one embodiment, the light emitting element40may be a conventional light emitting diode (LED), mini LED, or micro LED. “Micro LED” means LED with a grain size of fewer than 100 microns. The mini LED is also a sub-millimeter LED, its size is between conventional LED and micro LED. “Mini LED” generally means LED with a grain size of about 100 microns to 200 microns.

In one embodiment, after step S4, the method further includes forming an insulating block55between adjacent light emitting elements40and forming a cover57on a side of the light emitting element40away from the driving substrate50. Thereby, a display panel100ashown inFIG. 9is obtained. The adjacent light emitting elements40are insulated and are spaced from each other by one of the insulating blocks55. The cover57protects and seals the driving circuit layer52and the light emitting elements40from moisture and other contaminants.

In one embodiment, the light emitting elements40obtained by patterning the same crystal block30can emit light of one color. The patterning of light emitting elements40may also create elements40which emit light of different colors. For example, some crystal blocks30are patterned to form light emitting elements40emitting blue light, some crystal blocks30are patterned to form light emitting elements40emitting red light, and some crystal blocks30are patterned to form light emitting elements40emitting green light, and so on. Thereby, the display panel100acan be a color display panel.

In other embodiments, all the crystal blocks30are patterned to form light emitting elements40emitting light of one color. For example, all the crystal blocks30can be patterned to form light emitting elements40which emit red light, or all emitting green light, or all emitting blue light, and so on. Thereby, the display panel100acan be a monochrome display panel.

In one embodiment, all the crystal blocks30are patterned to form light emitting elements40emitting light of one color (e.g., blue light). The driving substrate50defines a plurality of sub-pixels (not shown), such as red pixels R, green pixels and blue pixels B. As shown inFIG. 10, after forming the insulating block55between adjacent light emitting elements40, the method further includes forming a wavelength conversion block54on a side of each of the light emitting elements40away from the conductive block53, and forming a black matrix56between adjacent wavelength conversion blocks54. A cover57is formed on a side of the light emitting element40away from the driving substrate50. Thereby, a display panel100bis obtained. The adjacent light emitting elements40are insulated by one of the insulating blocks55. The cover57seals and protects the driving circuit layer52and the light emitting element40.

In an embodiment, the wavelength conversion blocks54are made of quantum dots. For example, each of the light emitting elements40is a diode emitting blue light. The wavelength conversion blocks54include first wavelength conversion blocks541, second wavelength conversion blocks542, and third wavelength conversion blocks543, which may be quantum dots respectively outputting red color, green color, and blue color. The blue light emitted by the light emitting elements40undergoes wavelength conversion to realize color display of the display panel100b.

In other embodiments, the material of the wavelength conversion blocks54is a photoresist. For example, each of the light emitting elements40is a diode emitting blue light. The wavelength conversion blocks54include first wavelength conversion blocks541, second wavelength conversion blocks542, and third wavelength conversion blocks543, which apply a photoresist respectively for red, green, and blue colors. The blue light emitted by the light emitting elements40undergoes wavelength conversion to realize color display of the display panel100b.

In the method for making the display panel, after the crystal blocks30are transferred to the driving substrate50, each of the crystal blocks30is patterned to form a plurality of light emitting elements40. That is, one operation of alignment of the crystal blocks30and the receiving areas50aon the driving substrate50realizes the transfer a large number of light emitting elements40onto the driving substrate50. Compared with the method of one-to-one alignment and transfer of a large number of very small light emitting elements40and the conductive blocks53on the driving substrate50one by one, the number of alignments is greatly reduced. The manufacturing process is simplified, and the manufacturing time is greatly shortened. In addition, since the number of alignments is reduced, the yield of en masse transfers is improved.

It is to be understood, even though information and advantages of the present exemplary embodiments have been set forth in the foregoing description, together with details of the structures and functions of the present exemplary embodiments, the disclosure is illustrative only. Changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the present exemplary embodiments to the full extent indicated by the plain meaning of the terms in which the appended claims are expressed.