CN113497165B - Light emitting element mounting method and display device - Google Patents

Abstract

Provided are a method for mounting a light-emitting element using laser stripping and a display device. A method for mounting a light-emitting element in one embodiment is a method for stripping a light-emitting element provided on one surface of a sapphire substrate for stripping by laser stripping and mounting the light-emitting element on an array substrate. The method comprises: a step of fixing the array substrate to the sapphire substrate by a sealant, a step of applying pressure to the array substrate and the sapphire substrate to flatten the sapphire substrate and fix the array substrate to the sapphire substrate, a step of irradiating a first laser light of a first wavelength band from the sapphire substrate side and joining a first terminal portion of the array substrate to a terminal portion of the light-emitting element, and a step of irradiating a second laser light of a second wavelength band from the sapphire substrate side and stripping the light-emitting element from the sapphire substrate.

Description

Light emitting element mounting method and display device

This application is based on Japanese Patent Application No. 2020-067627 (filing date: April 3, 2020), and claims priority from the Japanese Patent Application No. 2020-067627, the entire contents of which are incorporated herein by reference.

Technical Field

Embodiments of the present invention relate to a method for mounting a light emitting element and a display device.

Background technique

Generally speaking, LED displays using light emitting diodes (LED) as self-luminous elements are known. However, in recent years, display devices using tiny diode elements called micro LEDs (hereinafter referred to as micro LED displays) have been developed as more sophisticated display devices.

This micro LED display is different from previous liquid crystal displays and organic EL displays. Since multiple micro LEDs in chip form are installed and formed in the display area, it is easy to achieve both high precision and large size, and it is attracting attention as the next generation display.

As a method of mounting a plurality of micro LEDs in a chip form in a display region, a method utilizing laser lift-off (LLO: Laser Lift Off) has been studied.

Summary of the invention

One of the purposes of the present disclosure is to provide a micro LED mounting method and a micro LED display (a light emitting element mounting method and a display device) using laser lift-off.

A method for mounting a light-emitting element in one embodiment is a method for mounting an array substrate by removing a light-emitting element disposed on one surface of a sapphire substrate for removal by laser removal. The method comprises a first step, a second step, a third step, and a fourth step. The first step performs alignment between a first terminal portion formed on one surface of the array substrate and a terminal portion of the light-emitting element, and fixes the array substrate to the sapphire substrate through a seal. The second step applies pressure to the array substrate and the sapphire substrate to flatten the sapphire substrate, and fixes the array substrate to the sapphire substrate. The third step irradiates a first laser light of a first wavelength band from the sapphire substrate side to a bonding component disposed on the first terminal portion of the array substrate, and joins the first terminal portion of the array substrate to the terminal portion of the light-emitting element. The fourth step irradiates a second laser light of a second wavelength band different from the first wavelength band from the sapphire substrate side to the light-emitting element, and removes the light-emitting element from the sapphire substrate.

A display device according to one embodiment includes a first substrate and a second substrate. The first substrate includes an array substrate, a first terminal portion formed on one surface of the array substrate, and a sealing member provided on one surface of the array substrate and provided at a position not overlapping with the first terminal portion when viewed from above. The second substrate includes a sapphire substrate and a light-emitting element provided on one surface of the sapphire substrate. The first substrate and the second substrate are fixedly connected by the sealing member.

A display device according to one embodiment includes an array substrate, a light emitting element provided on one surface of the array substrate, and a terminal portion formed on one surface of the array substrate and formed at a position not overlapping with the light emitting element when viewed from above. Residues of a sealing material melted during laser stripping for stripping the light emitting element from a sapphire substrate are attached to at least a portion of the terminal portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view schematically showing the configuration of a display device according to an embodiment.

FIG. 2 is a cross-sectional view schematically showing the structure of a first substrate according to the embodiment.

FIG. 3 is a cross-sectional view schematically showing the structure of the second substrate according to the embodiment.

FIG. 4 is a cross-sectional view schematically showing a step of mounting a light emitting element according to the embodiment.

FIG. 5 is a cross-sectional view schematically showing an installation step subsequent to FIG. 4 .

FIG. 6 is a cross-sectional view schematically showing an installation step subsequent to FIG. 5 .

FIG. 7 is a cross-sectional view schematically showing an installation step subsequent to FIG. 6 .

FIG. 8 is a cross-sectional view schematically showing the result of a series of mounting steps shown in FIG. 4 to FIG. 7 .

FIG. 9 is a cross-sectional view schematically showing the structure of a light emitting element according to an embodiment.

FIG. 10 is another cross-sectional view schematically showing the result of the series of mounting steps shown in FIGS. 4 to 7 .

FIG. 11 is another cross-sectional view schematically showing the structure of the second substrate according to the embodiment.

Detailed ways

Several embodiments will be described with reference to the drawings.

In addition, the disclosure is only an example, and solutions that can be easily thought of by those skilled in the art with appropriate changes that retain the main purpose of the invention are of course included in the scope of the present invention. In addition, in order to make the description clearer, the drawings are schematically shown compared with the embodiments, but they are only examples and do not limit the interpretation of the present invention. In addition, in this specification and each figure, the same reference numerals are given to the constituent elements that have the same or similar functions as the constituent elements described in relation to the figures that have appeared, and repeated detailed descriptions are sometimes omitted.

FIG. 1 is a perspective view schematically showing the structure of a display device 1 according to an embodiment. FIG. 1 shows a three-dimensional space defined by a first direction X, a second direction Y perpendicular to the first direction X, and a third direction Z perpendicular to the first direction X and the second direction Y. In addition, the first direction X and the second direction Y are orthogonal to each other, but may intersect at an angle other than 90 degrees. In this specification, the state of viewing the display device 1 from a direction parallel to the third direction Z is referred to as a top view.

Hereinafter, a case where the display device 1 is a micro LED display using micro LEDs as self-luminous elements in the present embodiment will be mainly described.

As shown in FIG. 1 , a display device 1 includes a display panel 2 , a first circuit board 3 , a second circuit board 4 , and the like.

The display panel 2 is rectangular in one example. In the illustrated example, the short side EX of the display panel 2 is parallel to the first direction X, and the long side EY of the display panel 2 is parallel to the second direction Y. The third direction Z is equivalent to the thickness direction of the display panel 2. The first direction X can also be interpreted as a direction parallel to the short side of the display device 1, the second direction Y can also be interpreted as a direction parallel to the long side of the display device 1, and the third direction Z can also be interpreted as the thickness direction of the display device 1. The main surface of the display panel 2 is parallel to the X-Y plane defined by the first direction X and the second direction Y. The display panel 2 has a display area DA (display portion) and a non-display area NDA (non-display portion) outside the display area DA. The non-display area NDA has a terminal area MT. In the illustrated example, the non-display area NDA surrounds the display area DA.

The display area DA is an area for displaying an image, and includes a plurality of pixels PX arranged in a matrix, for example. The pixels PX include a light emitting element (micro LED) and a switching element (driving transistor) for driving the light emitting element.

The terminal region MT is provided along the short side EX of the display panel 2 , and includes terminals for electrically connecting the display panel 2 to an external device or the like.

The first circuit substrate 3 is mounted on the terminal area MT and is electrically connected to the display panel 2. The first circuit substrate 3 is, for example, a flexible printed circuit board (Flexible Printed Circuit Board). The first circuit substrate 3 includes a driver IC chip (hereinafter referred to as a panel driver) 5 for driving the display panel 2, etc. In addition, in the example shown in the figure, the panel driver 5 is arranged on the first circuit substrate 3, but it can also be arranged under the first circuit substrate 3. Alternatively, the panel driver 5 can also be installed outside the first circuit substrate 3. In this case, the panel driver 5 can also be installed in the non-display area NDA of the display panel 2, and can also be installed in the second circuit substrate 4. The second circuit substrate 4 is, for example, a rigid printed circuit substrate. The second circuit substrate 4 is connected to the first circuit substrate 3, for example, below the first circuit substrate 3.

The panel driver 5 is connected to a control substrate (not shown) via, for example, the second circuit substrate 4. The panel driver 5 drives a plurality of pixels PX based on, for example, a video signal output from the control substrate, thereby controlling the display panel 2 to display an image.

In addition, the display panel 2 may also have a curved area BA indicated by adding oblique lines. The curved area BA is an area that is curved when the display device 1 is housed in a housing of an electronic device or the like. The curved area BA is located on the terminal area MT side in the non-display area NDA. In a state where the curved area BA is curved, the first circuit substrate 3 and the second circuit substrate 4 are arranged to face the display panel 2.

The following describes a method for mounting a light emitting element on the display panel 2. More specifically, the following describes a method for mounting the light emitting element LED on the first substrate SUB1 shown in FIG2 by peeling off the light emitting element LED from the second substrate SUB2 shown in FIG3 by laser lift-off (LLO). First, referring to FIG2 and FIG3, the configuration of the first substrate SUB1 on which the light emitting element LED is mounted and the second substrate SUB2 for peeling off are described.

FIG. 2 is a cross-sectional view schematically showing the structure of the first substrate SUB1.

As shown in FIG. 2 , the first substrate SUB1 includes an array substrate 10 , a plurality of first terminal portions 11 , a bonding member 12 , a plurality of second terminal portions 13 , a sealing member 14 , and the like.

The array substrate 10 includes a first main surface 10A and a second main surface 10B located on the opposite side of the first main surface 10A. Although omitted in the illustrated example, switch elements and various wiring patterns for driving the light-emitting elements LED are formed in the array substrate 10. The array substrate 10 may also be called a backplane.

A plurality of first terminal portions 11 are formed on the first main surface 10A of the array substrate 10. The first terminal portions 11 are formed, for example, in the same number as the light-emitting elements LED mounted on the display device 1. The first terminal portions 11 are formed of metal materials such as Al (aluminum), Ti (titanium), Mo (molybdenum), W (tungsten), and laminates of these metal materials. The first terminal portions 11 are also referred to as first pads or mounting electrodes. A bonding component 12 is disposed on each of the first terminal portions 11.

The joining component 12 is a component for joining the first terminal portion 11 to the terminal portion 22 of the light-emitting element LED described later. The details will be described later, but the joining component 12 is formed of a metal material that is heated/melted by laser ablation when irradiated with laser light in the wavelength band of 400nm to 3000nm, for example, it is formed of a metal material such as Sn (tin) and Ag (silver). The joining component 12 can also be called a soldering component. In addition, in the present embodiment, the joining component 12 is provided at the first terminal portion 11 of the array substrate 10, but can also be provided at the terminal portion 22 of the light-emitting element LED.

A plurality of second terminal portions 13 are formed on the first main surface 10A of the array substrate 10. The second terminal portion 13 is formed at a position that does not overlap with the first terminal portion 11 when viewed from above, for example, in a manner that surrounds a plurality of light-emitting elements LED provided in the display device 1. For example, the second terminal portion 13 is formed in the non-display area NDA. The second terminal portion 13 is formed with a width W1. The width W1 is set to, for example, 0.1 mm to 0.5 mm. The second terminal portion 13 is not electrically connected to various wiring patterns formed on the array substrate 10. However, the second terminal portion 13 may also be a terminal portion that is formed in the non-display area NDA in a manner that surrounds a plurality of light-emitting elements LED and is electrically connected to various wiring patterns formed on the array substrate 10. The details will be described later, but the second terminal portion 13 is formed of a metal material that is laser ablated by laser light, for example, a metal material such as Al (aluminum), and the laser light is irradiated to peel off the light-emitting element LED from the sapphire substrate 20 described later. The second terminal portion 13 may also be referred to as a second pad, a metal portion, or a metal wiring, etc. The sealing members 14 are disposed on the second terminal portions 13 so as to cover the second terminal portions 13 .

The sealing member 14 is a member for fixing the first substrate SUB1 and the second substrate SUB2 together and is formed of a material that transmits the laser light irradiated to the second terminal portion 13 .

The seal 14 and the second terminal portion 13 may also be formed along two short sides EX and two long sides in the non-display area NDA in a manner that surrounds the entire circumference of the display area DA of the first substrate SUB1, for example. Furthermore, the seal 14 and the second terminal portion 13 may also be formed only along the two short sides EX of the first substrate SUB1, or may also be formed only along the two long sides EY. Furthermore, the seal 14 and the second terminal portion 13 may also be formed so that a plurality of them are arranged in a dotted manner in the non-display area, and the first substrate SUB1 and the second substrate SUB2 are fixedly connected.

FIG3 is a cross-sectional view schematically showing the structure of the second substrate SUB2.

As shown in FIG3 , the second substrate SUB2 includes a sapphire substrate 20 and a plurality of light emitting elements LED, etc. The light emitting element LED includes a light emitting layer 21 and a terminal portion 22 .

The sapphire substrate 20 for peeling includes a first main surface 20A and a second main surface 20B located on the opposite side of the first main surface 20A. A plurality of light-emitting elements LED are arranged on the first main surface 20A of the sapphire substrate 20. The plurality of light-emitting elements LED include light-emitting elements LED having luminous colors of red (R), green (G), and blue (B).

The light-emitting layer 21 is fixed to the first main surface 20A of the sapphire substrate 20 via a peeling layer not shown. The light-emitting layer 21 releases R, G, and B light. A terminal portion 22 is arranged on the light-emitting layer 21. The terminal portion 22 is joined to the first terminal portion 11 through a joining component 12 arranged on the first substrate SUB1 side. Thus, the terminal portion 22 of the light-emitting element LED is electrically connected to the first terminal portion 11. The terminal portion 22 is equivalent to the anode terminal or cathode terminal of the light-emitting element LED. The terminal portion 22 can also be called a bump.

4 to 8 are schematic cross-sectional views sequentially showing an example of the mounting process of the light emitting element LED.

First, an alignment process (first process) is performed. Specifically, as shown in FIG4 , the first substrate SUB1 in which a plurality of first terminal portions 11, a bonding component 12, a plurality of second terminal portions 13, and a sealing member 14 are arranged on the array substrate 10 is opposed to the second substrate SUB2 in which a plurality of light-emitting elements LED are arranged on the sapphire substrate 20 in such a manner that the first principal surface 10A of the array substrate 10 is opposed to the first principal surface 20A of the sapphire substrate 20. On this basis, the plurality of first terminal portions 11 of the first substrate SUB1 and the terminal portions 22 of the plurality of light-emitting elements LED of the second substrate SUB2 are aligned. Furthermore, the first substrate SUB1 and the second substrate SUB2 are fixedly connected by the sealing member 14.

In addition, FIG. 4 assumes that the sapphire substrate 20 of the second substrate SUB2 does not warp, so at this stage, the plurality of first terminal portions 11 of the first substrate SUB1 overlap with the terminal portions 22 of the plurality of light-emitting elements LED of the second substrate SUB2 when viewed from above, but it is also possible that the plurality of first terminal portions 11 of the first substrate SUB1 and the terminal portions 22 of the plurality of light-emitting elements LED of the second substrate SUB2 do not overlap when viewed from above. At this stage, in the stage after the fixing process described later is completed, alignment is performed to make the plurality of first terminal portions 11 of the first substrate SUB1 overlap with the terminal portions 22 of the plurality of light-emitting elements LED of the second substrate SUB2 when viewed from above.

Next, a fixing process (second process) is performed. Specifically, as shown in FIG. 5 , a buffer 30 and a fixing component 40 are sequentially arranged on the second main surface 10B side of the array substrate 10 of the first substrate SUB1, and a fixing component 50 is arranged on the second main surface 20B side of the sapphire substrate 20 of the second substrate SUB2. On this basis, the warping generated on the sapphire substrate 20 is flattened by applying pressure from the top and bottom in a manner of clamping the first substrate SUB1 and the second substrate SUB2 (that is, each fixing component 40 and 50 is pressed in opposite directions to each other). As a result, the first substrate SUB1 and the second substrate SUB2 are fixed in a state in which the warping generated on the sapphire substrate 20 is flattened and the plurality of first terminal portions 11 of the first substrate SUB1 and the terminal portions 22 of the plurality of light-emitting elements LED of the second substrate SUB2 overlap when viewed from above. Furthermore, during the fixing process, the distance between the first substrate SUB1 and the second substrate SUB2 is maintained by the seal 14 and the light-emitting element LED, but the distance between the first substrate SUB1 and the second substrate SUB2 can also be maintained by providing a spacer (not shown) on the first substrate SUB1 or the second substrate SUB2.

The fixing member 50 is formed of a material that transmits the irradiated laser light in the bonding process described later and has a rigidity to the extent that it does not bend when pressure is applied, for example, it is formed of quartz glass. The fixing member 40 is formed of a material that has a rigidity to the extent that it does not bend when pressure is applied, for example, it can be formed of quartz glass like the fixing member 50, or it can be formed of a material different from the fixing member 50.

As described above, the buffer member 30 is disposed between the first substrate SUB1 and the fixing member 40, thereby suppressing damage to the array substrate 10 caused by the pressure for clamping the first substrate SUB1 and the second substrate SUB2. In addition, the first substrate SUB1 and the second substrate SUB2 are fixedly connected by the sealing member 14, so that the positional deviation that may occur due to the slippage of one substrate when pressure is applied can be suppressed.

Next, the bonding process (third process) is performed. Specifically, as shown in FIG. 6, by irradiating the bonding component 12 with laser light LZ1 in the wavelength band of 400nm to 3000nm from the fixing component 50 side, and heating/melting the bonding component 12 by laser ablation, the plurality of first terminal portions 11 of the first substrate SUB1 and the terminal portions 22 of the plurality of light-emitting elements LED of the second substrate SUB2 are bonded. At the stage where the bonding process is completed, the buffer 30, the fixing component 40, and the fixing component 50 may or may not be removed at this stage. In the present embodiment, it is assumed that the first substrate SUB1 and the second substrate SUB2 in the state where the bonding process is completed are moved to the workbench and the next process is performed on this basis, so the buffer 30, the fixing component 40, and the fixing component 50 are removed at the stage where the bonding process is completed.

After that, the LLO process (the fourth process) is performed. Specifically, as shown in FIG7 , the laser light LZ2 in the wavelength band of 200 nm to 366 nm is irradiated from the sapphire substrate 20 side toward the plurality of light-emitting elements LED and the plurality of second terminal portions 13. Thus, the peeling layer (not shown) that fixes the plurality of light-emitting elements LED to the sapphire substrate 20 is sublimated by laser ablation, and the plurality of light-emitting elements LED are peeled off from the sapphire substrate 20. Furthermore, if the plurality of second terminal portions 13 are heated by laser ablation, the heat is respectively conducted to the sealant 14 covering each second terminal portion 13, and the sealant 14 is melted and removed.

By performing a series of mounting steps shown in FIG. 4 to FIG. 7 , the sapphire substrate 20 is peeled off, and as shown in FIG. 8 , a plurality of light emitting elements LED are mounted on the first substrate SUB1 (array substrate 10 ).

As can be seen from the series of installation steps described above, the second terminal portion 13 is formed in order to melt the seal 14 by laser ablation, and the seal 14 is arranged in the above-mentioned fixing process in order to suppress the positional deviation that may occur when pressure is applied to the first substrate SUB1 and the second substrate SUB2, such as one substrate slipping. Therefore, after the series of installation steps are completed, the second terminal portion 13 basically becomes an unnecessary structure for the display panel 2, but it can also be used as an alignment mark for alignment when installing the first circuit substrate 3, the second circuit substrate 4, and the panel driver 5 for the array substrate 10 after the series of installation steps.

The light-emitting element LED of this embodiment may be a micro-LED in which an anode terminal 22AN and a cathode terminal 22CA are arranged in parallel on one surface of the light-emitting layer 21 as shown in FIG. 9 (A), or may be a micro-LED in which an anode terminal 22AN is arranged on one surface of the light-emitting layer 21 and a cathode terminal CA is arranged on the other surface of the light-emitting layer 21 as shown in FIG. 9 (B). In the case where the light-emitting element LED is a micro-LED in the manner shown in FIG. 9 (A), the first terminal portions 11 are formed on the array substrate 10 in the same number as the anode terminals 22AN and the cathode terminals 22CA, not the same number as the light-emitting element LEDs. In addition, with respect to the first terminal portions 11 corresponding to one light-emitting element LED, the first terminal portion 11 joined to the anode terminal 22AN and the first terminal portion 11 joined to the cathode terminal 22CA are formed to be separated by a predetermined interval. Regardless of whether the light-emitting element LED is a micro-LED in the manner shown in FIG. 9 (A) or a micro-LED in the form shown in FIG. 9 (B), it can be mounted on the first substrate SUB1 (array substrate 10) through the above-mentioned series of mounting steps.

FIG8 illustrates a case where the seal 14 arranged in a manner covering a plurality of second terminal portions 13 is completely removed by the above-mentioned LLO process, but in reality the seal 14 is not completely melted, and it can be expected that a portion of it remains attached to the second terminal portion 13 as a residue as shown in FIG10 (A). However, since the second terminal portion 13 is basically an unnecessary structure for the display panel 2 after a series of installation processes are completed as described above, there is no particular problem even if a portion of the seal 14 remains attached to the second terminal portion 13 as a residue. Furthermore, the second terminal portion 13 is arranged in the non-display area NDA, for example, so from the perspective of display quality, etc., there is no particular problem if a portion of the seal 14 remains attached to the second terminal portion 13 as a residue. However, the second terminal portion 13 may be removed together with the seal 14 attached as a residue as shown in FIG10 (B).

In this embodiment, it is assumed that the second terminal portion 13 is formed on the array substrate 10, but the present invention is not limited thereto, and the second terminal portion 13 may be formed on the sapphire substrate 20, for example, as shown in FIG11. In this case, the light emitting element LED can be mounted on the first substrate SUB1 (array substrate 10) through the above-mentioned series of mounting steps, and in the LLO process, the second terminal portion 13 is heated by laser ablation, so the sealing member 14 arranged in a manner to cover the second terminal portion 13 can also be removed.

In one embodiment described above, the first substrate SUB1 and the second substrate SUB2 are fixed by applying pressure in a manner of clamping the first substrate SUB1 on which the light-emitting element LED is mounted and the second substrate SUB2 for peeling. Therefore, even if warping occurs on the second substrate SUB2 (sapphire substrate 20), the warping can be flattened and the first substrate SUB1 and the second substrate SUB2 can be fixed without a gap. In addition, pressure is applied to the first substrate SUB1 on the basis of the buffer member 30 abutting against it, so that damage to the array substrate 10 of the first substrate SUB1 caused by the pressure can be suppressed.

Furthermore, in the embodiment described above, after the first substrate SUB1 on which the light-emitting element LED is mounted is fixedly connected to the second substrate SUB2 for peeling by the sealant 14, pressure is applied in a manner of sandwiching the first substrate SUB1 and the second substrate SUB2, thereby suppressing positional deviation that may occur due to slipping of one substrate when pressure is applied. Furthermore, by forming the second terminal portion 13 covered by the sealant 14 and laser ablated by the laser light LZ2 irradiated during the LLO process, the sealant 14 can be removed during the LLO process of peeling the light-emitting element LED from the second substrate SUB2. In other words, the removal of the sealant 14 can be achieved without adding a separate process just for removing the sealant 14.

According to one embodiment described above, it is possible to provide a micro LED mounting method and a micro LED display (a light emitting element mounting method and a display device) using laser lift-off.

Several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and can be omitted, replaced, and changed in various ways without departing from the scope of the invention. These embodiments and their variations are included in the scope and purpose of the invention, and are included in the invention described in the claims and the scope of their equivalents.

Description of Reference Numerals

SUB1…1st substrate, 10…array substrate, 11…1st terminal portion, 12…joining component, 13…2nd terminal portion, 14…sealing member, SUB2…2nd substrate, 20…sapphire substrate, LED…light emitting element, 21…light emitting layer, 22…terminal portion, LZ1, LZ2…laser light.

Claims (12)

1. A method for mounting a light-emitting element, wherein a light-emitting element disposed on one surface of a sapphire substrate for stripping is stripped by laser stripping, and then mounted on an array substrate, wherein the method comprises the following steps: In a first step, a first terminal portion formed on one surface of the array substrate is aligned with a terminal portion of the light emitting element, and the array substrate is fixedly bonded to the sapphire substrate via a sealing member; A second step of applying pressure to the array substrate and the sapphire substrate to flatten the sapphire substrate, and fixing the array substrate and the sapphire substrate; In a third step, irradiating a bonding component provided on the first terminal portion of the array substrate with a first laser light of a first wavelength band from the sapphire substrate side to bond the first terminal portion of the array substrate to the terminal portion of the light emitting element; and In the fourth step, the light emitting element is irradiated with a second laser light having a second wavelength band different from the first wavelength band from the sapphire substrate side to peel the light emitting element from the sapphire substrate. The fourth step includes the following steps: The second terminal portion formed on one surface of the array substrate or one surface of the sapphire substrate and covered with the sealing material is irradiated with the second laser light from the sapphire substrate side to heat the second terminal portion and melt the sealing material. 2. The method for mounting a light emitting element according to claim 1, wherein: The second step includes the following steps: After the buffer is brought into contact with the other surface of the array substrate, fixing components are further arranged on the other surface side of the array substrate and the other surface side of the sapphire substrate, and the fixing components are pressed in opposite directions to each other to apply pressure to the array substrate and the sapphire substrate. 3. The method for mounting a light emitting element according to claim 2, wherein: The fixing member disposed on the other surface side of the sapphire substrate transmits the first laser light irradiated in the third step. 4. The method for mounting a light emitting element according to any one of claims 1 to 3, wherein: The first wavelength band is 400nm to 3000nm. The above-mentioned second wavelength band is 200nm to 366nm. 5. The method for mounting a light emitting element according to any one of claims 1 to 3, wherein: The above-mentioned light emitting element is a micro LED. 6. A display device, comprising: a first substrate including an array substrate, a first terminal portion formed on one surface of the array substrate, and a sealing member provided on the one surface of the array substrate and provided at a position not overlapping with the first terminal portion when viewed from above; and a second substrate including a sapphire substrate and a light emitting element provided on one surface of the sapphire substrate, The first substrate and the second substrate are fixedly bonded together by the sealing member. The first substrate further includes a second terminal portion formed on one surface of the array substrate and covered by the sealing member. The second terminal portion is a terminal portion that is heated by being irradiated with laser light to melt the sealing material. 7. The display device according to claim 6, wherein: The light emitting element includes a light emitting layer and a terminal portion. The first terminal portion of the first substrate and the terminal portion of the light emitting element are bonded via a bonding member. 8. The display device according to claim 6, wherein: The first terminal portion is formed in a display area for displaying an image. The second terminal portion is formed in a non-display region arranged so as to surround the display region. 9. The display device according to claim 6 or 7, wherein: The above-mentioned light emitting element is a micro LED. 10. A display device having a light emitting element mounted thereon by the light emitting element mounting method according to claim 1, comprising: An array substrate; The light emitting element is arranged on one surface of the array substrate; and The terminal portion is formed on one surface of the array substrate and is formed at a position that does not overlap with the light emitting element when viewed from above. A residue of the sealing material melted during laser lift-off for removing the light emitting element from the sapphire substrate adheres to at least a portion of the terminal portion. 11. The display device according to claim 10, wherein: The light emitting element is arranged in a display area for displaying an image. The terminal portion is formed in a non-display region arranged to surround the display region. 12. The display device according to claim 10 or 11, wherein: The above-mentioned light emitting element is a micro LED.