Light-emitting element transfer apparatus and light-emitting element transfer method using the same

Abstract

The present invention provides an apparatus for transferring light-emitting elements and a method for transferring light-emitting elements using the same. [Solution] An luminescent element transfer apparatus and an luminescent element transfer method are provided. The luminescent element transfer apparatus may include a first transport head, a second transport head disposed below the first transport head, a stamp disposed below the second transport head, a tilt adjustment member for adjusting the inclination of the second transport head, and an air supply member that sprays air downward from one surface of the second transport head to form an air layer.

Description

Technical Field

[0001] The present invention relates to a light-emitting element transfer device and a light-emitting element transfer method using the same.

Background Art

[0002] With the development of multimedia, the importance of display devices has been increasing. Accordingly, various types of display devices such as organic light-emitting display devices (OLEDs) and liquid crystal display devices (LCDs) are being used.

[0003] As a device for displaying an image of a display device, there are display panels such as a light-emitting display panel and a liquid crystal display panel. Among them, the light-emitting display panel can include a light-emitting diode (LED), and the light-emitting diode includes an organic light-emitting diode using an organic substance as a fluorescent substance or an inorganic light-emitting diode using an inorganic substance as a fluorescent substance.

[0004] In the manufacture of a display panel using an inorganic light-emitting diode as a light-emitting diode, a manufacturing device for arranging micro LEDs (Micro LED) on the substrate of the display panel should be developed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The problem to be solved by the present invention is to provide a light-emitting element transfer device capable of effectively transferring a light-emitting element and a transfer method using the same.

[0007] The problems addressed by the present invention are not limited to those described above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0008] A light-emitting element transfer apparatus according to one embodiment for solving the above problem may include a first transport head, a second transport head disposed below the first transport head, a stamp disposed below the second transport head, a tilt adjustment member for adjusting the inclination of the second transport head, and an air supply member that sprays air downward from one surface of the second transport head to form an air layer.

[0009] The air supply member may include an air supply unit that supplies air, an injection head disposed on one surface of the second conveying head and having holes through which air is injected, and an injection line that passes through the second conveying head and connects the air supply unit and the injection head.

[0010] The aforementioned hole may be of one type, either a single hole type or a porous type.

[0011] The aforementioned air supply unit may be an air pump.

[0012] The first conveying head has a cavity with an inlet facing downwards, and the width of the inlet may be smaller than the width of the cavity.

[0013] The second transport head is divided into a first part located inside the cavity, a third part located outside the first transport head, and a second part located between the first and third parts, and the width of the second part may be narrower than the widths of the first and second parts.

[0014] The tilt adjustment member may include a first permanent magnet positioned on the first conveying head, and a second permanent magnet positioned on the first part of the second conveying head, facing the first permanent magnet and having a repulsive force with the first permanent magnet.

[0015] The second transport head has a chuck on one side, which can be used to hold a stamp in place.

[0016] The second conveying head is divided into a first part located within the cavity, a third part located outside the first conveying head, a second part located between the first and third parts, and an inclined part located between the first and second parts, wherein the width of the second part may be narrower than the widths of the first and second parts.

[0017] The inclination adjustment member may include a plurality of second permanent magnets arranged in the first part and the inclined part, and a plurality of first permanent magnets arranged in the first transport member so as to correspond to the plurality of second permanent magnets.

[0018] The light-emitting element transfer apparatus may further include a pressurizing member positioned between the first and second transport heads within the cavity of the first transport head, which pressurizes the second transport head downward.

[0019] The pressurizing member may be a spring.

[0020] The pressurizing member may include an elastic membrane placed on the second conveying head within the cavity of the first conveying head, a gas pipe connected between the elastic membrane and the cavity, and a gas supply member that supplies gas to the gas pipe.

[0021] The first transport head, the second transport head, and the tilt adjustment member may be air gyros.

[0022] Multiple injection heads may be arranged discontinuously around the stamp.

[0023] The spray heads can be arranged continuously around the stamp.

[0024] The first transport head includes a chuck located at its lower part, which can hold the stamp in place.

[0025] The light-emitting element transfer method may include the steps of disposing a transfer mechanism described in the light-emitting element transfer apparatus according to the embodiment on a substrate; forming an air layer between the second transfer head and the substrate by the air supply member and lowering the transfer mechanism - the thickness of the air layer being greater than the sum of the height of the stamp and the height of the light-emitting element -; adjusting the flatness of the transfer mechanism to match the flatness of the substrate; and lowering the second transfer head downward, pressurizing the air layer, and bringing the light-emitting element into contact with the substrate for transfer - the thickness of the air layer being the same as the sum of the height of the stamp and the height of the light-emitting element -.

[0026] In the step of disposing the transfer mechanism on the substrate, the light-emitting elements disposed on the stamp may be aligned on the substrate based on a first alignment key disposed on one surface of the stamp and a second alignment key disposed on the substrate.

[0027] In the step of adjusting to match the flatness of the substrate, the tilt adjustment member may adjust the second transfer head to match the flatness of the substrate while the second transfer head is not in contact with the first transfer head.

[0028] In the step of forming an air layer between the second transfer head and the substrate by the air supply member and lowering the transfer mechanism, the air supply unit may supply air to the injection head along an injection line, and the injection head may inject air downward to form an air layer.

Advantages of the Invention

[0029] A light-emitting element transfer apparatus capable of effectively transferring a light-emitting element and a transfer method using the same can be provided.

[0030] When employing a display panel manufacturing method according to one embodiment, high-precision alignment can be achieved by ensuring the relative flatness between the stamp and the substrate while the light-emitting element is in non-contact with the substrate. Therefore, by reducing defects in the light-emitting element, the product quality of the display panel can be improved and the yield can be increased. This effect is particularly excellent on large-area substrates.

[0031] The effects of the embodiments are not limited to those exemplified above, and a wider variety of effects are included herein. [Brief explanation of the drawing]

[0032] [Figure 1] This is a layout diagram showing a display device according to one embodiment. [Figure 2] This is an illustrative diagram showing an example of a pixel in Figure 1. [Figure 3] This is an illustrative diagram showing yet another example of the pixels in Figure 1. [Figure 4] This is a cross-sectional view showing an example of a display panel cut along line A-A' in Figure 2. [Figure 5] This is a schematic diagram illustrating a light-emitting element transfer apparatus LTD according to one embodiment. [Figure 6] This is a schematic diagram illustrating the transfer mechanism according to one embodiment. [Figure 7] This is a plan view of a spray head according to one embodiment. [Figure 8] This diagram illustrates the operation of the air injection member in Figure 7. [Figure 9] This is a plan view illustrating the number and shape of the air injection components. [Figure 10] This is a plan view illustrating the number and shape of the air injection components. [Figure 11] This is a plan view illustrating the number and shape of the air injection components. [Figure 12] This is a plan view illustrating the number and shape of the air injection components. [Figure 13]This diagram illustrates the operation of a light-emitting element transfer device that does not include a tilt adjustment member and an air injection member. [Figure 14] This is a schematic diagram illustrating the transfer mechanism of a light-emitting element according to another embodiment. [Figure 15] This is a schematic diagram illustrating the transfer mechanism of a light-emitting element according to another embodiment. [Figure 16] This is a schematic diagram illustrating the transfer mechanism of a light-emitting element according to another embodiment. [Figure 17] This is a schematic diagram illustrating the transfer mechanism of a light-emitting element according to another embodiment. [Figure 18] This is a schematic diagram illustrating the transfer mechanism of a light-emitting element according to another embodiment. [Figure 19] This is a schematic diagram illustrating the transfer mechanism of a light-emitting element according to another embodiment. [Figure 20] This is a flowchart showing a method for transferring a light-emitting element according to one embodiment. [Figure 21] This is a cross-sectional view illustrating a method for transferring light-emitting elements. [Figure 22] This is a cross-sectional view illustrating a method for transferring light-emitting elements. [Figure 23] This is a cross-sectional view illustrating a method for transferring light-emitting elements. [Figure 24] This is a cross-sectional view illustrating a method for transferring light-emitting elements. [Figure 25] This is a cross-sectional view illustrating a method for transferring light-emitting elements. [Figure 26] This is an illustrative diagram showing a smartwatch including a display device according to one embodiment. [Figure 27] This is an illustrative diagram showing a virtual reality device including a display device according to one embodiment. [Figure 28] This is an illustrative diagram showing a virtual reality device including a display device according to one embodiment. [Figure 29] This is an illustrative diagram showing a virtual reality device including a display device according to another embodiment. [Figure 30] This is an illustrative diagram showing the instrument panel and center fascia of a vehicle including a display device according to one embodiment. [Figure 31] This is an illustrative diagram showing a transparent display device including a display device according to one embodiment. [Modes for carrying out the invention]

[0033] The advantages and features of the present invention, as well as methods for achieving them, will become clearer with reference to the embodiments described below in detail, along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and can be realized in a variety of different forms, and these embodiments are provided merely to complete the disclosure of the present invention and to fully inform those who are ordinary skill in the art to which the invention pertains, of the scope of the invention, and the present invention is defined solely by the scope of the claims.

[0034] When an element or layer is referred to as "on" another element or layer, this includes all cases where the other layer or other element is interposed immediately above or between the other element. Throughout the specification, the same reference numerals refer to the same component. The shapes, sizes, proportions, angles, numbers, etc. disclosed in the drawings illustrating embodiments are illustrative and the invention is not limited to those shown.

[0035] The following describes specific embodiments with reference to the attached drawings.

[0036] Figure 1 is a layout diagram showing a display device according to one embodiment. Figure 2 is an illustrative diagram showing an example of the pixels in Figure 1. Figure 3 is an illustrative diagram showing yet another example of the pixels in Figure 1.

[0037] Referring to Figures 1 to 3, the display device can be used as a display screen for a variety of products, including not only portable electronic devices such as mobile phones, smartphones, tablet PCs, smartwatches, watch phones, mobile communication terminals, electronic organizers, e-books, PMPs (portable multimedia players), navigation systems, and UMPCs (Ultra Mobile PCs), as well as televisions, laptops, monitors, billboards, and Internet of Things (IoT) devices, as a device for displaying videos and still images.

[0038] The display panel 100 can be formed as a rectangular plane having a long side in a first direction DR1 (indicated as x in Figure 1, etc.) and a short side in a second direction DR2 (indicated as y in Figure 2, etc.) that intersects with the first direction DR1. The corner where the long side of the first direction DR1 and the short side of the second direction DR2 intersect can be formed rounded or at a right angle to have a predetermined curvature. The planar shape of the display panel 100 is not limited to a rectangle, but can be formed as other polygons, circles, or ellipses. The display panel 100 is formed flat, but is not limited to this. For example, the display panel 100 may include curved surfaces formed at the left and right ends that have a constant curvature or a changing curvature. The display panel 100 can also be formed flexibly so that it can be bent, warped, folded, or rolled up.

[0039] The display panel 100 may further include pixels PX, scan wiring extending in a first direction DR1, and data wiring extending in a second direction DR2 for displaying an image. The pixels PX may be arranged in a matrix in the first direction DR1 and the second direction DR2.

[0040] Each pixel PX may contain multiple sub-pixels RP, GP, and BP, as shown in Figures 2 and 3. While Figures 2 and 3 show that each pixel PX contains three sub-pixels RP, GP, and BP, namely a first sub-pixel RP, a second sub-pixel GP, and a third sub-pixel BP, the embodiments described herein are not limited to this.

[0041] The first subpixel RP, the second subpixel GP, and the third subpixel BP may be connected to any one of the data lines and at least one of the scan lines.

[0042] Each of the first subpixel RP, second subpixel GP, and third subpixel BP can have a rectangular, square, or rhombus-shaped planar shape. For example, each of the first subpixel RP, second subpixel GP, and third subpixel BP can have a rectangular planar shape with a short side in the first direction DR1 and a long side in the second direction DR2, as shown in Figure 2. Alternatively, each of the first subpixel RP, second subpixel GP, and third subpixel BP can have a square or rhombus-shaped planar shape with sides of the same length in the first direction DR1 and the second direction DR2, as shown in Figure 3.

[0043] As shown in Figure 2, the first subpixel RP, the second subpixel GP, and the third subpixel BP may be arranged in the first direction DR1. Alternatively, either the second subpixel GP or the third subpixel BP and the first subpixel RP may be arranged in the first direction DR1, and the remaining one and the first subpixel RP may be arranged in the second direction DR2. For example, as shown in Figure 3, the first subpixel RP and the second subpixel GP may be arranged in the first direction DR1, and the first subpixel RP and the third subpixel BP may be arranged in the second direction DR2.

[0044] Alternatively, either the first subpixel RP or the third subpixel BP and the second subpixel GP may be arranged in the first direction DR1, and the remaining one and the second subpixel GP may be arranged in the second direction DR2. Alternatively, either the first subpixel RP or the second subpixel GP and the third subpixel BP may be arranged in the first direction DR1, and the remaining one and the third subpixel BP may be arranged in the second direction DR2.

[0045] A first subpixel RP may include a first light-emitting element that emits first light, a second subpixel GP may include a second light-emitting element that emits second light, and a third subpixel BP may include a third light-emitting element that emits third light. Here, the first light may be light in the red wavelength band, the second light in the green wavelength band, and the third light in the blue wavelength band. The red wavelength band is generally in the 600nm to 750nm range, the green wavelength band is generally in the 480nm to 560nm range, and the blue wavelength band is generally in the 370nm to 460nm range, but the embodiments described herein are not limited thereto.

[0046] Each of the first subpixel RP, second subpixel GP, and third subpixel BP may include an inorganic light-emitting element having an inorganic semiconductor as a light-emitting element. For example, the inorganic light-emitting element may be a flip-chip type microLED (Light Emitting Diode), but the embodiments herein are not limited thereto.

[0047] As shown in Figures 2 and 3, the areas of the first subpixel RP, the second subpixel GP, and the third subpixel BP may be substantially identical, but the embodiments herein are not limited thereto. At least one of the areas of the first subpixel RP, the second subpixel GP, and the third subpixel BP may also be different from the other one. Alternatively, any two of the areas of the first subpixel RP, the second subpixel GP, and the third subpixel BP may be substantially identical, and the remaining one may be different from the other two. Alternatively, the areas of the first subpixel RP, the second subpixel GP, and the third subpixel BP may be different from each other.

[0048] Figure 4 is a cross-sectional view showing an example of a display panel cut along line A-A' in Figure 2.

[0049] Referring to Figure 4, the display panel 100 may include a thin-film transistor layer TFTL and a light-emitting element LE, which are disposed on a substrate SUB. The thin-film transistor layer TFTL may be a layer on which thin-film transistors (TFTs) are formed.

[0050] The thin-film transistor layer TFTL includes an active layer ACT, a first gate layer GTL1, a second gate layer GTL2, a first data metal layer DTL1, a second data metal layer DTL2, a third data metal layer DTL3, and a fourth data metal layer DTL4. The thin-film transistor layer TFTL also includes a buffer film BF, a gate insulating film 130, a first interlayer insulating film 141, a second interlayer insulating film 142, a first planarization film 160, a first insulating film 161, a second planarization film 180, and a second insulating film 181.

[0051] The substrate SUB may be a base substrate or base member for supporting a display device. The substrate SUB may be a rigid substrate made of glass material, but the embodiments herein are not limited thereto. The substrate SUB may be a flexible substrate that can be bent, folded, rolled, etc. In this case, the substrate SUB may contain an insulating material such as a polymer resin such as polyimide (PI).

[0052] A buffer film BF is placed on one surface of the substrate SUB. The buffer film BF may be a film that prevents the penetration of air or moisture. The buffer film BF consists of multiple inorganic films that are alternately stacked. For example, the buffer film BF can be formed as a multilayer film in which one or more inorganic films from among silicon nitride layers, silicon oxynitride layers, silicon oxide layers, titanium oxide layers, and aluminum oxide layers are alternately stacked. The buffer film BF may be omitted.

[0053] An active layer ACT is placed on the buffer film BF. The active layer ACT may contain a silicon semiconductor such as polycrystalline silicon, single-crystal silicon, low-temperature polycrystalline silicon, and amorphous silicon, or an oxide semiconductor.

[0054] The active layer ACT may include the channel TCH, first electrode TS, and second electrode TD of the thin-film transistor TFT. The channel TCH of the thin-film transistor TFT may be a region that overlaps with the gate electrode TG of the thin-film transistor TFT in a third direction DR3 (indicated as z in Figure 1, etc.), which is the thickness direction of the substrate SUB. The first electrode TS of the thin-film transistor TFT is located on one side of the channel TCH, and the second electrode TD is located on the other side of the channel TCH. The first electrode TS and the second electrode TD of the thin-film transistor TFT may be regions that do not overlap with the gate electrode TG in the third direction DR3. The first electrode TS and the second electrode TD of the thin-film transistor TFT may be conductive regions in which ions are doped into a silicon semiconductor or oxide semiconductor.

[0055] A gate insulating film 130 is placed on the active layer ACT. The gate insulating film 130 can be formed from an inorganic film, such as a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, a titanium oxide layer, or an aluminum oxide layer.

[0056] A first gate layer GTL1 is placed on the gate insulating film 130. The first gate layer GTL1 may include the gate electrode TG and the first capacitor electrode CAE1 of the thin-film transistor TFT. The first gate layer GTL1 can be formed as a single or multilayer from one of the following materials or alloys: molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu).

[0057] A first interlayer insulating film 141 is placed on the first gate layer GTL1. The first interlayer insulating film 141 can be formed from an inorganic film, such as a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, a titanium oxide layer, or an aluminum oxide layer.

[0058] A second gate layer GTL2 is placed on the first interlayer insulating film 141. The second gate layer GTL2 may include a second capacitor electrode CAE2. The second gate layer GTL2 can be formed as a single or multilayer from one of the following materials or an alloy thereof: molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu).

[0059] A second interlayer insulating film 142 is placed on the second gate layer GTL2. The second interlayer insulating film 142 can be formed from an inorganic film, such as a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, a titanium oxide layer, or an aluminum oxide layer.

[0060] A first data metal layer DTL1, including a first connecting electrode CE1, a first sub-pad SPD1 (not shown), and a data wiring DL, is disposed on the second interlayer insulating film 142. The data wiring DL is formed integrally with the first sub-pad SPD1 (not shown), but the embodiments herein are not limited thereto. The first data metal layer DTL1 can be formed as a single or multilayer from one of the following: molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof.

[0061] The first connecting electrode CE1 can be connected to the first electrode TS or second electrode TD of the thin-film transistor TFT via a first contact hole CT1 that penetrates the gate insulating film 130, the first interlayer insulating film 141, and the second interlayer insulating film 142.

[0062] On the first data metal layer DTL1, an active layer ACT, a first gate layer GTL1, a second gate layer GTL2, and a first planarization film 160 for flattening the step created by the first data metal layer DTL1 are arranged. The first planarization film 160 can be formed from an organic film such as acrylic resin, epoxy resin, phenolic resin, polyamide resin, or polyimide resin.

[0063] A first insulating film 161 is disposed on the first planarization film 160. A second data metal layer DTL2 is disposed on the first insulating film 161. The second data metal layer DTL2 may include a second connecting electrode CE2 and a second sub-pad PD2 (not shown). The second connecting electrode CE2 may be connected to the first connecting electrode CE1 via a second contact hole CT2 that penetrates the first insulating film 161 and the first planarization film 160. The second data metal layer DTL2 can be formed as a single or multilayer from one of the following: molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof.

[0064] A second planarization film 180 is placed on the second data metal layer DTL2. The second planarization film 180 can be formed from an organic film such as acrylic resin, epoxy resin, phenolic resin, polyamide resin, or polyimide resin.

[0065] A second insulating film 181 is disposed on the second planarization film 180. A third data metal layer DTL3 is disposed on the second insulating film 181. The third data metal layer DTL3 may include a third connecting electrode CE3 and a third sub-pad SPD3 (not shown). The third connecting electrode CE3 may be connected to the second connecting electrode CE2 via a third contact hole CT3 that penetrates the second insulating film 181 and the second planarization film 180. The third data metal layer DTL3 can be formed as a single or multilayer from one of the following: molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof.

[0066] A third planarization film 190 is placed on the third data metal layer DTL3. The third planarization film 190 can be formed from an organic film such as acrylic resin, epoxy resin, phenolic resin, polyamide resin, or polyimide resin.

[0067] A fourth data metal layer DTL4 is disposed on the third planarization film 190. A third insulating film 191 (not shown) may be disposed between the third planarization film 190 and the fourth data metal layer DTL4. The fourth data metal layer DTL4 may include an anode pad electrode APD, a cathode pad electrode CPD, and a fourth sub-pad SPD (not shown). The anode pad electrode APD may be connected to a third connecting electrode CE3 via a fourth contact hole CT4 that penetrates the third planarization film 190 or penetrates the third insulating film 191 and the third planarization film 190. The cathode pad electrode CPD may receive a first power supply voltage, which is a low potential voltage. The fourth data metal layer DTL4 can be formed as a single or multilayer from one of the following: molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof.

[0068] The light-emitting element LE has been shown to be a flip-chip type microLED in which the first contact electrode CTE1 and the second contact electrode CTE2 are arranged to face the anode pad electrode APD and the cathode pad electrode CPD, but is not limited to this. The light-emitting element LE may be an inorganic light-emitting element made of an inorganic material such as GaN. The lengths of the first direction DR1, the second direction DR2, and the third direction DR3 of the light-emitting element LE may each be several to several hundred μm. For example, the lengths of the first direction DR1, the second direction DR2, and the third direction DR3 of the light-emitting element LE may each be approximately 100 μm or less.

[0069] Light-emitting elements (LEs) can be grown and formed on a semiconductor substrate such as a silicon wafer. Each light-emitting element (LE) can be immediately transferred from the silicon wafer onto the anode pad electrode (APD) and cathode pad electrode (CPD) of the substrate (SUB). In this case, the first contact electrode (CTE1) and the anode pad electrode (APD) can be bonded to each other by a bonding process. Similarly, the second contact electrode (CTE2) and the cathode pad electrode (CPD) can be bonded to each other by a bonding process. The first contact electrode (CTE1) and the anode pad electrode (APD) can be electrically connected to each other via a bonding electrode (23). Similarly, the second contact electrode (CTE2) and the cathode pad electrode (CPD) can be electrically connected to each other via the bonding electrode (23).

[0070] As an example, a bonding electrode 23 is placed on one surface of the light-emitting element LE. The bonding electrode 23 may be a bond formed by pressure fusion bonding using a laser. Here, pressure fusion bonding refers to a state in which the bonding electrode 23 is heated and melted, the light-emitting element LE, the anode pad electrode APD and the cathode pad electrode CPD are melted and mixed, and then cooled and solidified when the laser supply is terminated. Since the conductivity of the light-emitting element LE, the anode pad electrode APD and the cathode pad electrode CPD is maintained even as the molten mixture cools and solidifies, the anode pad electrode APD and the cathode pad electrode CPD can be electrically connected to the light-emitting element LE and physically connected to each other. Therefore, the bonding electrode 23 can be placed on the first contact electrode CTE1 and the second contact electrode CTE2 of the light-emitting element LE.

[0071] The junction electrode 23 may include, for example, Au, AuSn, PdIn, InSn, NiSn, Au-Au, AgIn, AgSn, Al, Ag, or carbon nanotubes (CNTs). These can be used individually or in combination of two or more.

[0072] Each of the light-emitting elements (LEs) may be a light-emitting structure comprising a base substrate (SSUB), an n-type semiconductor (NSEM), an active layer (MQW), a p-type semiconductor (PSEM), a first contact electrode (CTE1), and a second contact electrode (CTE2).

[0073] The base substrate SSUB may be a sapphire substrate, but the embodiments herein are not limited thereto.

[0074] An n-type semiconductor NSEM is placed on one surface of a base substrate (SSUB). For example, an n-type semiconductor NSEM is placed on the bottom surface of a base substrate (SSUB). An n-type semiconductor NSEM consists of GaN doped with n-type conductive dopants such as Si, Ge, and Sn.

[0075] The active layer MQW is positioned on a portion of one surface of an n-type semiconductor NSEM. A p-type semiconductor PSEM is positioned on the other surface of the active layer MQW. The active layer MQW may contain materials with a single or multiple quantum well structure. If the active layer MQW contains materials with a multiple quantum well structure, it may have a structure in which multiple well layers and barrier layers are alternately stacked. In this case, the well layers are formed of InGaN, and the barrier layers are formed of GaN or AlGaN, but are not limited to these. Alternatively, the active layer MQW may have a structure in which semiconductor materials with large bandgap energies and semiconductor materials with small bandgap energies are alternately stacked, and may contain different group 3 to group 5 semiconductor materials depending on the wavelength band of the emitted light.

[0076] In one embodiment of the present invention, a flip-chip type light-emitting element was used as an example, but the invention is not limited to this, and a vertical type light-emitting element may also be used.

[0077] Figure 5 is a schematic diagram showing a light-emitting element transfer apparatus LTD according to one embodiment.

[0078] According to one embodiment, the light-emitting element transfer apparatus LTD is a device used for transferring light-emitting elements.

[0079] As shown in Figure 5, the light-emitting element transfer apparatus LTD comprises a drive mechanism DU, a transfer mechanism TDU, a stage STG, and a controller CTU.

[0080] The drive mechanism DU enables the transfer mechanism TDU to move up, down, left, and right. The drive mechanism DU may include an XY drive unit DU-1 and a Z drive unit DU-2.

[0081] The XY drive unit DU-1 moves the transfer mechanism TDU above the stage STG on which the light-emitting element LE is placed.

[0082] The Z drive unit DU-2 lowers the transfer mechanism TDU to bring it closer to the light-emitting element LE, which is the target of pickup, to a predetermined distance.

[0083] The transfer mechanism TDU is a device for picking up light-emitting elements (LEs).

[0084] The transfer mechanism TDU may include, for example, one of the following chucks: an electrostatic chuck, an adhesive chuck, a vacuum chuck, or a porous vacuum chuck. The transfer mechanism TDU can use the chuck to adsorb and lift the light-emitting element LE. In one embodiment, an example of transferring the light-emitting element LE to a substrate TS is shown, but it is not limited to this, and can be applied to SOI flip-chip mounting in which flip chips are connected to bumps arranged in an array shape on the substrate TS, or it can be applied to so-called die bonding in which the light-emitting element LE is bonded to the substrate TS.

[0085] The structure of the TDU transcription mechanism will be explained in detail with reference to Figure 6.

[0086] The stage STG supports the circuit board TS. The stage STG is positioned in the center of the XY drive unit DU-1. The stage STG may, but is not limited to, be positioned to be movable in the Y direction.

[0087] The controller CTU is connected to the drive mechanism DU and the transfer mechanism TDU, and is configured to perform the necessary processing for transfer by controlling the operation of these components. The controller CTU has, for example, an interface (not shown) for sending and receiving signals to and from each of the aforementioned components, such as the drive mechanism DU and the transfer mechanism TDU. The controller CTU is configured to provide feedback to the bonding process based on detection results from cameras, sensors, etc. For example, the controller CTU recognizes the alignment keys of the light-emitting element LE and the substrate TS based on images captured by the camera and detects their positions. Based on the detection results, the controller CTU controls the XY drive unit DU-1 and the Z drive unit DU-2 to perform control related to the transfer operation, which aligns the position of the light-emitting element LE, etc.

[0088] Next, the configuration of the aforementioned transfer mechanism TDU will be described.

[0089] Figure 6 is a schematic diagram showing the configuration of a transfer mechanism according to one embodiment. Figure 7 is a plan view of the injection head according to one embodiment, and Figure 8 is a diagram illustrating the drive of the air injection member in Figure 7.

[0090] Referring to Figure 6, the transfer mechanism TDU may include a first transfer head 210, a second transfer head 220, a stamp 230, a tilt adjustment member 240, and an air injection member 250.

[0091] The first transport head 210 is connected to the Z drive unit DU-2 and is for supporting the second transport head 220.

[0092] The first conveying head 210 has a cavity with an entrance in the first direction. The width of the entrance may be smaller than the width of the cavity.

[0093] The second transport head 220 is positioned below the first transport head 210.

[0094] The second transport head 220 is divided into three parts: part 1 220-a, part 220-b, and part 3 220-c. Part 1 220-a is located inside the cavity of the first transport head 210, part 3 220-c is located outside the first transport head 210, and part 220-b is located between part 1 220-a and part 3 220-c. Part 220-b is located at the entrance of the cavity.

[0095] The second part 220-b is formed with a narrower width than the first part 220-a and the third part 220-c, and can be formed so that the first part 220-a overlaps the cavity of the first conveyor head 210. The first part 220-a conforms to the shape of the cavity of the first conveyor head 210. For example, if the cavity is rectangular, the first part 220-a can also have a rectangular shape. Because the cavity portion corresponding to the first part 220-a is wider than the cavity portion corresponding to the second part 220-b, it is possible to prevent the second conveyor head 220 from coming out of the cavity portion corresponding to the second part 220-b. Furthermore, since the cavity in the part corresponding to the third section 220-c is wider than the cavity in the part corresponding to the second section 220-b, it is possible to suppress limitations on the size of the chuck 221 and other components placed in the cavity in the part corresponding to the third section 220-c, and on the stamp 230 that can be adsorbed by the chuck 221. Specifically, in the example shown in Figure 6, the first conveyor head 210 has an entrance in the downward direction in the Z direction and a cavity that extends upward from the entrance. The cavity is formed inside the first conveyor head 210 and does not penetrate the first conveyor head 210. As shown in the cross-sectional view in Figure 6, in the XY plane, the width of the entrance in the X direction is smaller than the width of the cavity in the X direction. As a result, the first conveyor head 210 is formed to have a step, with an inward recess in the cavity. In the second conveyor head 220, the width of the first part 220-a in the X direction is larger than the width of the second part 220-b in the X direction. As a result, the second conveyor head 220 is formed to have a shape that is inwardly recessed from the first part 220-a to the second part 220-b, and has a step. The steps of the first part 220-a and the second part 220-b are positioned to correspond to the steps of the first conveyor head 210, and the second conveyor head 220 is fitted inside the first conveyor head 210. The third part 220-c is continuous with the outside of the first conveyor head 210 from the lower part of the second part 220-b downward in the Z direction. Therefore, in the second conveyor head 220, the third part 220-c mainly protrudes downward in the Z direction from the first conveyor head 210. In the example in Figure 6, parts of the first part 220-a and the second part 220-b of the second conveyor head 220 are formed to conform to the shape of the cavity of the first conveyor head 210, and are formed to be slightly smaller than the cavity of the first conveyor head 210.

[0096] The second transport head 220 may include one chuck 221 on one surface, which is one of the following: an electrostatic chuck, an adhesive chuck, a vacuum chuck, or a porous vacuum chuck. For example, the chuck 221 is positioned on one surface of the third section 220-c. The stamp 230 can be attracted to one surface of the second transport head 220 by the chuck 221. In the example in Figure 6, the third section 220-c has a recess facing downwards, into which the chuck 221 is fitted. The lower surface of the chuck 221, which faces downwards, is configured to attract the stamp 230. The lower surface of the chuck 221 is aligned with the XY plane (horizontal plane).

[0097] The stamp 230 is positioned below the second transport head 220.

[0098] Stamp 230 may include multiple layers. For example, stamp 230 may include a base layer and a stamp layer. The base layer may be aligned with, for example, an XY plane (horizontal plane). The stamp layer may also be aligned with, for example, an XY plane (horizontal plane).

[0099] The base layer supports the stamp layer. The base layer consists of, for example, polyethylene terephthalate (PET), polyurethane (PU), polyimide (PI), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polysulfone (PSF), polymethyl methacrylate (PMMA), triacetylcellulose (TAC), cycloolefin polymer (COP), etc.

[0100] The stamp layer is positioned on one surface of the base layer. For example, the upper layer of stamp 230 in the Z direction is the base layer, and the lower layer of stamp 230 in the Z direction is the stamp layer, which is continuous with the bottom surface of the base layer. The stamp layer includes a plurality of protrusions and can adhere or bond the light-emitting element LE. The stamp layer is made of an adhesive or tacky material. Adhesive materials include, for example, OCA (Optical Clear Adhesive) and PSA (Pressure Sensitive Adhesive), while tacky materials include, for example, acrylic, urethane, and silicone adhesives. The plurality of protrusions are formed on the stamp layer so as to project downward in the Z direction. One end face of the plurality of protrusions is flat, and the shape of the protrusions may be a polygonal prism or a cylinder. For example, one end face is the downward end face in the Z direction, and this end face is aligned with the XY plane (horizontal plane).

[0101] The tilt adjustment member 240 can adjust the relative flatness between the stamp 230 and the substrate TS by adjusting the tilt of the second transport head 220.

[0102] The tilt adjustment member 240 may include a plurality of permanent magnets. The tilt adjustment member 240 is formed by a plurality of pairs of permanent magnets. A pair of permanent magnets may include a plurality of first permanent magnets 241 and a plurality of second permanent magnets 242. The plurality of first permanent magnets 241 are mounted in recesses of the first conveyor head 210. The plurality of second permanent magnets 242 are mounted in recesses of the second conveyor head 220. In the example in Figure 6, a plurality of recesses are provided in the first conveyor head 210 facing the cavity, and a first permanent magnet 241 is embedded in each recess of the first conveyor head 210. Similarly, a plurality of recesses are provided in the second conveyor head 220, and a second permanent magnet 242 is embedded in each recess of the second conveyor head 220. For example, multiple second permanent magnets 242 are attached to the first surface 220-a1, second surface 220-a2, third surface 220-a3, and fourth surface 220a-4 of the first part 220-a of the second transport head 220. Multiple first permanent magnets 241 may be arranged in the cavity of the first transport head 210 in positions opposite to a pair of second permanent magnets 242. The number of first permanent magnets 241 is the same as the number of second permanent magnets 242. The first surface 220-a1 is the upper surface along the horizontal plane in the first part 220-a. The second surface 220-a2 is a side surface that is continuous with the first surface 220-a1 and perpendicular to the first surface 220-a1. The third surface 220-a3 is the surface opposite to the second surface 220-a2, is continuous with the first surface 220-a1 and perpendicular to the first surface 220-a1. The fourth surface 220a-4 is the surface of the portion that is stepped with the second part 220-b in the first part 220-a, is continuous with the second surface 220-a2 and the third surface 220-a3, and is the lower surface along the horizontal plane perpendicular to the second surface 220-a2 and the third surface 220-a3. Recesses are provided on each of the first surface 220-a1, second surface 220-a2, third surface 220-a3, and fourth surface 220a-4, and a second permanent magnet 242 is embedded in each recess. Each recess of the first transport head 210 and each recess of the second transport head 220 are arranged to correspond to each other. Furthermore, in the second transport head 220, a side surface extends from the fourth surface 220a-4 and is perpendicular to the fourth surface 220a-4. The inner surface of the cavity of the first transport head 210 has sides that are aligned with these first to fourth surfaces 220-a1 to a4 and the side surface extending from the fourth surface 220a-4.

[0103] Therefore, the first permanent magnet 241 and the second permanent magnet 242 are positioned facing each other. Also, the first permanent magnet 241 and the second permanent magnet 242 are positioned with the same polarity facing each other. For example, the south polarity of the first permanent magnet 241 and the south polarity of the second permanent magnet 242 face each other. The magnetic forces between the opposing magnetic poles of the first permanent magnet 241 and the second permanent magnet 242 balance each other, and the second transport head 220 floats within the cavity of the first transport head 210 without the first permanent magnet 241 and the second permanent magnet 242 coming into contact with each other.

[0104] Figure 6 shows a total of five pairs of first permanent magnets 241 and second permanent magnets 242 arranged, but the tilt adjustment member 240 can adjust the tilt of the second transport head 220, and the number and position of the first permanent magnets 241 and second permanent magnets 242 are not limited to this.

[0105] Furthermore, the magnetic force between the first permanent magnet 241 and the second permanent magnet 242 also plays a role in returning the second transport head 220 to its original position once the external force is removed, even if the second transport head 220 is tilted due to an external force acting on it.

[0106] Because the second transport head 220 is floating due to the repulsive force between the first permanent magnet 241 and the second permanent magnet 242, the first transport head 210 does not tilt even if the second transport head 220 tilts. Conversely, the second transport head 220 may tilt depending on the flatness of the substrate placed below it.

[0107] The air injection member 250 injects air downward from one surface of the second conveying head 220 to form an air layer.

[0108] For example, the system includes an injection head 251, an injection line 252, and an air supply unit 253, wherein air injected from the air supply unit 253 can be discharged along the injection line 252 through the injection head 251.

[0109] The injection head 251 is positioned around the stamp 230 on one side (the bottom surface) of the second transport head 220. By discharging air downward (for example, towards the substrate TS) from the injection head 251, an air layer can be formed between the injection head 251 and the substrate TS. The thickness of the air layer can be adjusted by the amount of air discharged from the air supply unit 253, and can be formed to a thickness that prevents the light-emitting element LE attached to the stamp 230 from coming into contact with the substrate TS.

[0110] The injection head 251 can be formed in a hole type configuration to ensure that the incoming air is ejected evenly, but is not limited to this. Examples of hole-type structures include one hole 251-1 as shown in Figure 7a, or a porous type with numerous voids 251-2 on a predetermined plane as shown in Figure 7b, which can be formed to ensure that gas is ejected evenly across the entire plane. The shape of the hole on the plane can be circular or square, but is not limited to these.

[0111] In this specification, “on a plane” is defined with respect to a plane (xy-plane) parallel to the planes defined by the first direction DR1 and the second direction DR2. In this specification, “on a cross-section” is defined as the view from the first direction DR1 (x-direction) or the second direction DR2 (y-direction).

[0112] Furthermore, the injection head 251 can be formed with a shape that narrows downwards in cross-section to improve the efficiency of downward air injection. Alternatively, the injection head 251 can be formed with a shape that widens downwards.

[0113] The injection line 252 is a pipe that supplies gas to the injection head 251 and may pass through a portion of the second transport head 220.

[0114] As shown in Figure 8, the air supply unit 253 continuously ejects air from the injection head 251 via the injection line 252 for a certain period of time. The duration is at least the time required to move the light-emitting element LE, which is located on one surface of the stamp 230, to the substrate TS.

[0115] When air is ejected downward from the injection head 251, the pressure of the ejected air pushes the second transport head 220 upward in the opposite direction to the direction of air movement. As a result, the second transport head 220 becomes floating at a first distance ht away from the substrate TS. The first distance ht is greater than the sum of the height h1 of the stamp 230 in the third direction (z direction) and the height h2 of the light-emitting element LE, as will be described later.

[0116] The air supply unit 253 supplies air. For example, the air supply unit 253 may be, but is not limited to, an air pump. For example, the air supply unit 253 may supply inert or extremely unreactive gases such as nitrogen (N2), helium (He), neon (Ne), argon (Ar), carbon dioxide (CO2), or mixtures thereof.

[0117] The air supply unit 253 may further include a reservoir for storing air (or gas), and a valve for regulating the flow of the air (or gas). The air supply unit 253 may also eject air to the injection head 251 via the injection line 252.

[0118] Figures 9 through 12 are plan views illustrating the number and shape of the injection heads.

[0119] As can be seen by referring to Figures 9 through 12, the number and shape of the injection heads can be varied in many ways.

[0120] Referring to Figures 9 to 12, the stamp 230 can conform to the shape of the second conveyor head 220 in a plane. For example, if the second conveyor head 220 has a rectangular shape in a plane, the shape of the stamp 230 in a plane may also be rectangular, but is not limited to this. For example, the second conveyor head 220 and the stamp 230 may be circular. In this specification, “in a plane” is defined with respect to a plane parallel to the planes defined by the first direction DR1 and the second direction DR2. In this specification, “in a cross-section” is defined as the view from the first direction DR1 or the second direction DR2.

[0121] The spray head 251 is positioned around the stamp 230 on one surface of the second transport head 220. The spray head 251 does not overlap with the stamp 230 on the plane.

[0122] Referring to Figures 9 and 10, multiple injection heads can be circular.

[0123] For example, referring to Figure 9(a), multiple injection heads 251 may be positioned at each of the four corners of the second transport head 220.

[0124] Referring to Figure 9(b), multiple injection heads 251 can be positioned at the center of each side of the second transport head 220.

[0125] Referring also to Figure 10(a), the multiple injection heads 251 can be positioned at the four corners and the center of each side of the second transport head 220, respectively.

[0126] Furthermore, referring to Figure 10(b), multiple injection heads 251 can be arranged on each side of the second transport head 220, excluding the four corners. For example, three injection heads 251 can be arranged on each side, but the number of injection heads 251 is not limited to this.

[0127] Referring to Figure 10(c), multiple injection heads 251 can be arranged at the four corners and on each side of the second transport head 220. Each injection head 251 is arranged at equal intervals from one another, but is not limited to this arrangement.

[0128] Referring to Figure 11, the multiple injection heads 251 can be polygons with corners.

[0129] Referring to Figure 11(a), the multiple injection heads 251 can be arranged so as not to overlap with the stamp 230 at the four corners of the second transport head 220, but to be separated from the stamp 230 and surrounding the corners of the stamp 230. For example, the injection heads 251 may be L-shaped or inverted L-shaped.

[0130] Referring to Figure 11(b), the multiple injection heads 251 are rectangular and can be positioned at the center of each side of the second transport head 220.

[0131] Referring to Figure 11(c), the multiple injection heads 251 may have different shapes from each other. For example, the multiple injection heads 251 may be arranged so as to surround the corners of the stamp 230 with the four corners of the second transport head 220, and furthermore, each may be arranged in a rectangle at the center of each side of the second transport head 220.

[0132] Referring to Figures 9 and 11, it can be seen that the injection heads 251 are arranged discontinuously around the stamp 230.

[0133] Referring to Figure 12, the injection heads 251 can be arranged continuously around the stamp 230. For example, the injection heads 251 may be a single rectangular shape surrounding the stamp 230 in the second transport head 220.

[0134] As can be seen by referring to Figures 9 and 12, the number and shape of the air injection members can be varied in many ways.

[0135] Figure 13 is a diagram illustrating the operation of a light-emitting element transfer device that does not include a tilt adjustment member and an air injection member.

[0136] In the case of a light-emitting element transfer apparatus that does not include a tilt adjustment member (240 in Figure 6) and an air injection member (250 in Figure 6), warping or tilting of the substrate TS may cause rotation of the stamp 230 after the light-emitting element LE attached to the stamp 230 comes into contact with the surface of the substrate TS. This causes a change in the planar position of the light-emitting element LE due to the rotation of the stamp 230. For example, when the height of the substrate TS decreases from one end to the other, the light-emitting element LE will first come into contact with the higher end of the substrate TS. The light-emitting element LE that first comes into contact with the surface of the substrate TS may be tilted or its alignment disrupted due to the force acting on the surface of the substrate TS in the planar direction. For example, in a light-emitting element transfer apparatus that does not have a tilt adjustment member (240 in Figure 6) and an air injection member (250 in Figure 6), when transferring light-emitting elements LE to a substrate TS, multiple light-emitting elements LE attached to the lower surface of a stamp (230 in Figure 6, included in the TDU in Figure 13) are brought into contact with the upper surface of the substrate TS. When the lower surface of the stamp and the upper surface of the substrate TS are aligned approximately parallel to each other (when the lower surfaces of multiple light-emitting elements LE and the upper surface of the substrate TS are aligned approximately parallel to each other), the multiple light-emitting elements LE are pressed toward the upper surface of the substrate TS with approximately equal pressure in the downward direction in the Z direction, thereby allowing them to be positioned at the desired location on the substrate TS while suppressing damage and misalignment. On the other hand, as mentioned above, when the upper surface of the substrate TS is warped or tilted, and the lower surface of the stamp and the upper surface of the substrate TS are not aligned approximately parallel to each other (when the lower surfaces of multiple light-emitting elements LE and the upper surface of the substrate TS are not aligned approximately parallel to each other), the stamp rotates due to the reaction force received from the substrate TS by the light-emitting element LE that first contacts the substrate TS. In other words, the stamp rotates so that the lower surface of the stamp (in the aforementioned planar direction) aligns with the upper surface of the substrate TS. In this case, for example, the light-emitting element LE that first contacts the substrate TS becomes the center point, receiving the reaction force mainly from the substrate TS, and the stamp rotates. Multiple light-emitting elements (LEs) are not subjected to uniform pressure, but rather unevenly. In particular, light-emitting elements that are primarily subjected to uneven pressure may suffer damage, misalignment, and other problems. Furthermore, in the case of large-area substrate TSs, this problem is even more serious because warping and tilting of the substrate TS occur frequently.

[0137] Figure 14 is a schematic diagram illustrating the transfer mechanism of a light-emitting element according to another embodiment.

[0138] Referring to Figure 14, there is a difference from Figure 6 in that a pressurizing member 270 is included between the first transport head 210 and the second transport head 220 instead of a pair of permanent magnets. The components other than the pressurizing member 270 can be similarly applied to those described with reference to Figures 6 to 12, and the following description will focus on the pressurizing member 270.

[0139] The pressurizing member 270 is located in a recess of the first conveying head 210 and positioned between the first conveying head 210 and the second conveying head 220, allowing the second conveying head 220 to be pressurized while maintaining the space between the first conveying head 210 and the second conveying head 220. In the example shown in Figure 14, the pressurizing member 270 is fitted across a recess formed on the upper inner surface of the cavity of the first conveying head 210 and a recess formed on the upper surface facing the cavity of the second conveying head 220. The pressurizing member 270 in Figure 14 can pressurize the second conveying head 220 in the Z direction.

[0140] Furthermore, the pressurizing member 270 may include, for example, a spring, but is not limited thereto. When the pressurizing member 270 is formed of a spring, it is possible to prevent the transmission of sudden pressure when a pressurizing force is applied from the top to the bottom of the first conveying head 210.

[0141] In one embodiment, a single pressurizing member 270 is shown to be placed between the first conveying head 210 and the second conveying head 220, but this does not limit the number of pressurizing members 270. For example, multiple springs may be placed between the first conveying head 210 and the second conveying head 220.

[0142] Figure 15 is a schematic diagram illustrating the transfer mechanism of a light-emitting element according to another embodiment.

[0143] Referring to Figure 15, there is a difference from Figure 6 in that a pressurizing member 270 is included between the first conveying head 210 and the second conveying head 220. The components other than the pressurizing member 270 can be similarly described with reference to Figures 6 to 12, and the following description will focus on the pressurizing member 270. In the example of Figure 15, a part of the pressurizing member 270 is supported on the upper surface of the inner surface of the cavity in the first conveying head 210. The remaining part of the pressurizing member 270 extends toward the second conveying head 220 and is formed to be in contact with the upper surface of the second conveying head 220. The pressurizing member 270 in Figure 15 can pressurize the second conveying head 220 in the Z direction.

[0144] In one embodiment, the pressurizing member 270 may include an elastic membrane 271, a gas pipe 272, and a gas supply member 273.

[0145] The elastic membrane 271 is formed of an elastic material such as an elastomer. It is located in the cavity of the first conveying head 210 and is positioned between the first conveying head 210 and the second conveying head 220, and a space S can be present between the elastic membrane 271 and the first conveying head 210. The pressurizing member 270 is designed to maintain the space between the first conveying head 210 and the second conveying head 220.

[0146] The gas pipe 272 supplies gas to the space S between the elastic membrane 271 and the first conveying head 210, causing the elastic membrane 271 to expand downwards. When the elastic membrane 271 expands, it pressurizes the second conveying head 220.

[0147] The gas supply member 273 supplies gas to the space S via the gas pipe 272. The gas supply member 273 ultimately controls the pressure applied to the second conveying head 220 by controlling the expansion force of the elastic membrane 271.

[0148] The gas supply member 273 can supply inert or extremely chemically reactive gases to the internal space, such as nitrogen (N2), helium (He), neon (Ne), argon (Ar), carbon dioxide (CO2), or mixtures thereof. Hereinafter, gases having such inertness or extremely low chemical reactivity will be referred to as neutral gases.

[0149] Figure 16 is a schematic diagram illustrating the transfer mechanism of a light-emitting element according to another embodiment.

[0150] Referring to Figure 16, the second transport head 220 further includes an inclined section 220-ab between the first section 220-a and the second section 220-b, and differs from Figure 6 in that the number of inclination adjustment members 240 is fewer compared to Figure 6.

[0151] The inclined portion 220-ab is positioned between the first portion 220-a, which has a first width Wa, and the second portion 220-b, which has a second width Wb, and has an inclination angle with a surface parallel to the first surface 220-a1 of the first portion 220-a by connecting one end of the first portion 220-a and one end of the second portion 220-b. In the example of Figure 16, the second transport head 220 is composed of the first portion 220-a, the inclined portion 220-ab, the second portion 220-b, and the third portion 220-c, from top to bottom in the Z direction. As shown in Figure 16, the width of the second portion 220-b in the X direction is smaller than the width of the first portion 220-a in the X direction. The inclined portion 220-ab is positioned to connect the first portion 220-a and the second portion 220-b from the lower end of the first portion 220-a to the upper end of the second portion 220-b. As shown in Figure 16, the inclined section 220-ab is formed such that its width in the X direction narrows from the top to the bottom in the Z direction. Furthermore, the cavity of the first conveying head 210 is formed to have an inclined surface in the inclined section 220-ab, in accordance with the shape of the second conveying head 220 in Figure 16.

[0152] The tilt adjustment member 240 may include a total of three pairs of permanent magnets, arranged on the first surface 220-a1 and the inclined portion 220-ab of the second transport head 220. Each pair of permanent magnets may include a plurality of first permanent magnets 241 and a plurality of second permanent magnets 242.

[0153] Multiple first permanent magnets 241 are attached to the first transport head 210. Multiple second permanent magnets 242 are attached to the second transport head 220. For example, multiple second permanent magnets 242 are attached to the first surface 220-a1 of the first part 220-a of the second transport head 220, and to the second surface (inclined surface) 220-a2 of the inclined part 220-ab of the second transport head 220. Multiple first permanent magnets 241 can be arranged in a position facing a pair of second permanent magnets 242 within the cavity of the first transport head 210. The number of first permanent magnets 241 is the same as the number of second permanent magnets 242. That is, as shown in Figure 16, in the second transport head 220, the second permanent magnets 242 are arranged in the recesses formed in the first surface 220-a1 and the recesses formed in the inclined surface of the inclined part 220-ab. Furthermore, in the first transport head 210, the first permanent magnet 241 is positioned in a recess formed on the upper surface of the cavity, facing the recess of the first surface 220-a1, and in a recess facing the recess of the inclined surface (second surface 220-a2) of the inclined portion 220-ab.

[0154] Figure 17 is a schematic diagram illustrating the transfer mechanism of a light-emitting element according to another embodiment.

[0155] Referring to Figure 17, there is a difference from Figure 16 in that a pressurizing member 270 is included between the first transport head 210 and the second transport head 220 instead of a pair of permanent magnets. The other components can be similarly described with reference to Figure 16, and the following description will focus on the pressurizing member 270.

[0156] The pressurizing member 270 has the same configuration and arrangement as in Figure 14, and is positioned across the recess of the first conveying head 210 and the recess of the second conveying head 220, and is positioned between the first conveying head 210 and the second conveying head 220. For example, it can be positioned between the second conveying head 220 and the first conveying head 210 in the cavity of the first conveying head 210. Therefore, the second conveying head 220 can be pressurized while maintaining the space between the first conveying head 210 and the second conveying head 220.

[0157] Furthermore, the pressurizing member 270 may include, for example, a spring, but is not limited thereto. By forming the pressurizing member 270 with a spring, it is possible to prevent the transmission of sudden pressure when a pressurizing force is applied from the top to the bottom of the first conveying head 210.

[0158] In one embodiment, a single pressurizing member 270 is shown to be placed between the first conveying head 210 and the second conveying head 220, but this does not limit the number of pressurizing members 270. For example, multiple springs may be placed between the first conveying head 210 and the second conveying head 220.

[0159] Figure 18 is a schematic diagram illustrating the transfer mechanism of a light-emitting element according to another embodiment.

[0160] Referring to Figure 18, there is a difference from Figure 16 in that a pressurizing member 270 is included between the first transport head 210 and the second transport head 220 instead of a pair of permanent magnets. The other components can be similarly applied to those described with reference to Figure 15, and the following description will focus on the pressurizing member 270.

[0161] In one embodiment, the pressurizing member 270 may include an elastic membrane 271, a gas pipe 272, and a gas supply member 273. Similar to Figure 15, the pressurizing member 270 is partially supported by the first conveying head 210, with the remaining portion formed to be in contact with the upper surface of the second conveying head 220.

[0162] The elastic membrane 271 is formed of an elastic material such as an elastomer. It is located in the cavity of the first conveying head 210 and positioned between the first conveying head 210 and the second conveying head 220, and a space S can be maintained between the elastic membrane 271 and the first conveying head 210. The pressurizing member 270 is designed to maintain the space between the first conveying head 210 and the second conveying head 220.

[0163] The gas pipe 272 supplies gas to the space S between the elastic membrane 271 and the first conveying head 210, causing the elastic membrane 271 to expand downwards. When the elastic membrane 271 expands, it pressurizes the second conveying head 220.

[0164] The gas supply member 273 supplies gas to the space S via the gas pipe 272.

[0165] The gas supply member 273 can supply inert or extremely chemically reactive gases to the internal space, such as nitrogen (N2), helium (He), neon (Ne), argon (Ar), carbon dioxide (CO2), or mixtures thereof. Hereinafter, gases having such inertness or extremely low chemical reactivity will be referred to as neutral gases.

[0166] Figure 19 is a schematic diagram illustrating the transfer mechanism of a light-emitting element according to another embodiment.

[0167] Referring to Figure 19, the first transport head 210, the second transport head 220, and the tilt adjustment member 240 are formed from air gyro AG, which differs from Figure 6 in that they do not contain permanent magnets.

[0168] The air gyro AG can adjust the relative flatness between the stamp 230 and the substrate TS instead of the permanent magnets shown in Figure 6. The relative flatness between the stamp 230 and the substrate TS can be adjusted more precisely by the air gyro AG. The air gyro AG is configured, for example, to attract the second transport head 220 towards the first transport head 210, or to supply compressed air to the second transport head 220 away from the first transport head 210, thereby further adjusting the relative flatness between the stamp 230 and the substrate TS.

[0169] Figure 20 is a flowchart showing a method for transferring light-emitting elements according to one embodiment. Figures 21 to 25 are cross-sectional views illustrating the method for transferring light-emitting elements. Figures 21 to 25 show cross-sectional views of the structure of the transfer apparatus according to the transfer order of the light-emitting elements. Figures 21 to 25 mainly show the transfer mechanism TDU and the light-emitting element LE, which generally correspond to the cross-sectional or plan view of the transfer mechanism TDU described with reference to Figures 6 to 12, respectively. Below, in addition to Figure 20, the method for transferring light-emitting elements shown in Figures 21 to 25 will be described.

[0170] First, the transfer mechanism TDU is placed on the substrate TS (S110 in Figure 20).

[0171] Referring to Figure 21, the stamp 230 of the transfer mechanism TDU is equipped with a light-emitting element LE and a first alignment key AM1.

[0172] The second alignment key AM2 is located on the circuit board TS.

[0173] The first alignment key AM1 and the second alignment key AM2 can be formed by a photolithography process.

[0174] As explained in Figure 5, the XY drive unit DU-1 and the Z drive unit DU-2 of the light-emitting element transfer device LTD allow the transfer mechanism TDU to be positioned at the desired location.

[0175] For example, the transfer mechanism TDU can determine the relative positions of the first alignment key AM1 and the second alignment key AM2 positioned on the stamp 230 and position the stamp 230 on the substrate TS. For example, two second alignment keys AM2 are positioned on the substrate TS, and the stamp 230 is positioned on the substrate TS such that the first alignment key AM1 faces the second alignment keys AM2. By adjusting the position of the transfer mechanism TDU so that the first alignment key AM1 is positioned between multiple second alignment keys AM2, the light-emitting element LE can be positioned at a desired location on the substrate TS.

[0176] Next, the air injection member 250 ejects air, causing the transfer mechanism TDU to descend (S120 in Figure 20).

[0177] For example, as shown in Figure 22, air is ejected from the injection head 251, pressurizing the transfer mechanism TDU downwards.

[0178] The air supply unit 253 supplies air to the injection head 251 along the injection line 252, and the injection head 251 injects air downward (for example, towards the substrate TS). As air is ejected from the injection head 251, an air layer is formed beneath the injection head 251. This air layer generates a force that pushes the second transport head 220 outwards from the substrate TS. When the force of the ejected air is in equilibrium with the pressure applied by the transfer mechanism TDU, a constant distance can be maintained between the substrate TS and the light-emitting element LE. This constant distance can be adjusted by the amount of air ejected by the air supply unit 253. Furthermore, if the constant distance is greater than the sum of the height of the light-emitting element LE and the height of the stamp 230, the light-emitting element LE does not directly contact the substrate TS. Although the second transport head 220 is not in contact with the substrate TS, the force of the ejected air can support the second transport head 220.

[0179] Furthermore, as described above, the tilt adjustment member 240 generates a magnetic force between the first conveyor head 210 and the second conveyor head 220. In other words, even if a constant pressure is applied from above, the second conveyor head 220 can maintain a floating state due to the magnetic force of the tilt adjustment member 240 and the amount of air injected by the air injection member 250.

[0180] Next, the flatness of the second transport head 220 is adjusted by the tilt adjustment member 240 to match the flatness of the substrate TS (S130 in Figure 20).

[0181] For example, as shown in Figure 23, the second transport head 220 is in a floating state and supported by an air layer formed below the injection head 251. Then, while the light-emitting element LE is not in contact with the substrate TS, the movement of the second transport head 220 can be adjusted so that the flatness of the second transport head 220 is the same as the flatness of the substrate TS. For example, as mentioned above, as shown in Figure 22, if the substrate TS is tilted or warped, when the transfer mechanism TDU is lowered, a part of the transfer mechanism TDU approaches the substrate TS in a non-contact state. By adjusting the amount of spray from the spray head 251, the entire transfer mechanism TDU approaches the substrate TS in a non-contact state so as to correspond to the tilt or warp of the substrate TS. As a result, as shown in Figure 22, for example, the light-emitting element LE maintains a non-contact state with the substrate TS, and the lower surface of the second transport head 220 (the lower surface of the stamp 230, the lower surface of the light-emitting element LE) and the upper surface of the substrate TS are aligned with each other, that is, the relative flatness is matched, and the second transport head 220 is positioned on the substrate TS.

[0182] This ensures that the alignment of the light-emitting elements LE remains undisturbed while the relative flatness of the second transport head 220 and the substrate TS is adjusted. Therefore, the accuracy of the light-emitting elements LE can be ensured.

[0183] Next, the second transport head 220 is pressurized to transfer the light-emitting element LE (S140 in Figure 20).

[0184] For example, as shown in Figure 24, the second transport head 220 can be lowered further to pressurize the air layer in order to bring the light-emitting element LE into contact with the substrate TS. This reduces the thickness of the air layer, allowing the light-emitting element LE to come into contact with the substrate TS. The thickness (or height) ht of the air layer at this time may be the same as the sum of the height h2 of the light-emitting element LE in the third direction and the height h1 of the substrate.

[0185] The air injection member 250 controls the amount of air injected to limit the lowering position of the light-emitting element LE. For example, the air injection member 250 can limit the minimum amount of air injected to prevent excessive lowering of the second transport head 220. Because the lowering position is limited by the air injection member 250, it does not cause damage to the light-emitting element LE.

[0186] Next, referring to Figure 25, the transfer mechanism TDU can be lifted to separate the light-emitting element LE from the stamp 230. The second transport head 220 returns to its predetermined position within the cavity of the first transport head 210 by the permanent magnets 241 and 242, which are the tilt adjustment members 240. In the above, the tilt adjustment member 240 may include a permanent magnet. However, an electromagnet may be used instead of a permanent magnet. The tilt of the second transport head 220 can also be adjusted by the tilt adjustment member 240 by adjusting the current supplied to the electromagnet and the direction of the current. Alternatively, power may be used instead of a permanent magnet.

[0187] Conventional techniques, such as laser irradiation methods, can be applied to separate the stamp 230 from the light-emitting element LE.

[0188] Figure 26 is an illustrative diagram showing a smartwatch including a display device according to one embodiment.

[0189] Referring to Figure 26, the display device 10_1 according to one embodiment can be applied to a smartwatch 1000_1, which is a type of smart device.

[0190] Figures 27 and 28 are illustrative diagrams showing a virtual reality device including a display device according to one embodiment.

[0191] Referring to Figures 27 and 28, a head-mounted display device 1000_2 according to one embodiment includes a first display device 10_2, a second display device 10_3, a display device housing 1100, a housing cover 1200, a first eyepiece 1210, a second eyepiece 1220, a head mounting band 1300, a middle frame 1400, a first optical member 1510, a second optical member 1520, and a control circuit board 1600.

[0192] The first display device 10_2 provides an image to the user's left eye, and the second display device 10_3 provides an image to the user's right eye. Since the first display device 10_2 and the second display device 10_3 are substantially identical to the display device 10 described with reference to Figures 1 and 2, the explanation of the first display device 10_2 and the second display device 10_3 will be omitted.

[0193] The first optical member 1510 is positioned between the first display device 10_2 and the first eyepiece lens 1210. The second optical member 1520 is positioned between the second display device 10_3 and the second eyepiece lens 1220. Each of the first optical member 1510 and the second optical member 1520 may include at least one convex lens.

[0194] The middle frame 1400 is positioned between the first display device 10_2 and the control circuit board 1600, and between the second display device 10_3 and the control circuit board 1600. The middle frame 1400 serves to support and secure the first display device 10_2, the second display device 10_3, and the control circuit board 1600.

[0195] The control circuit board 1600 is positioned between the middle frame 1400 and the display device housing 1100. The control circuit board 1600 can be connected to the first display device 10_2 and the second display device 10_3 via connectors. The control circuit board 1600 can convert an externally input video source into digital video data DATA and transmit the digital video data DATA to the first display device 10_2 and the second display device 10_3 via connectors.

[0196] The control circuit board 1600 can transmit digital video data corresponding to the left eye image optimized for the user's left eye to the first display device 10_2, and digital video data corresponding to the right eye image optimized for the user's right eye to the second display device 10_3. Alternatively, the control circuit board 1600 can transmit the same digital video data to both the first display device 10_2 and the second display device 10_3.

[0197] The display device housing 1100 houses the first display device 10_2, the second display device 10_3, the middle frame 1400, the first optical member 1510, the second optical member 1520, and the control circuit board 1600. The housing cover 1200 is positioned to cover one open side of the display device housing 1100. The housing cover 1200 may include a first eyepiece 1210 in which the user's left eye is positioned and a second eyepiece 1220 in which the user's right eye is positioned. Figures 27 and 28 show the first eyepiece 1210 and the second eyepiece 1220 being positioned separately, but the embodiments herein are not limited thereto. The first eyepiece 1210 and the second eyepiece 1220 can be integrated.

[0198] The first eyepiece 1210 is aligned with the first display device 10_2 and the first optical element 1510, and the second eyepiece 1220 is aligned with the second display device 10_3 and the second optical element 1520. Therefore, the user can view the image of the first display device 10_2, magnified as a virtual image by the first optical element 1510, through the first eyepiece 1210, and the image of the second display device 10_3, magnified as a virtual image by the second optical element 1520, through the second eyepiece 1220.

[0199] The head mounting band 1300 secures the display device housing 1100 to the user's head so that the first eyepiece 1210 and the second eyepiece 1220 of the storage cover 1200 remain positioned for the user's left and right eyes, respectively. If the display device housing 1100 is lightweight and compact, the head-mounted display device 1000_2 may be equipped with a spectacle frame instead of the head mounting band 1300, as shown in Figure 29.

[0200] Furthermore, the head-mounted display device 1000_2 may further include a battery for supplying power, an external memory slot for storing external memory, and an external connection port and wireless communication module for receiving video sources. The external connection port may be a USB (universe serial bus) terminal, a DisplayPort, or an HDMI® (high-definition multimedia interface) terminal, and the wireless communication module may be a 5G communication module, a 4G communication module, a Wi-Fi module, or a Bluetooth® module.

[0201] Figure 29 is an illustrative diagram showing a virtual reality device including a display device according to another embodiment. Figure 29 shows a virtual reality device 1000_3 to which a display device 10_4 according to one embodiment is applied.

[0202] Referring to Figure 29, one embodiment of the virtual reality device 1000_3 may be a glasses-type device. One embodiment of the virtual reality device 1000_3 may include a display device 10_4, a left eye lens 10a, a right eye lens 10b, a support frame 20, temples 30a, 30b, a reflective member 40, and a display device housing 50.

[0203] Figure 29 shows that the virtual reality device 1000_3 is a glasses-type display device including temples 30a and 30b. In other words, the virtual reality device 1000_3 according to one embodiment is not limited to the one shown in Figure 26, but can be applied in various forms to a variety of other electronic devices.

[0204] The display device housing 50 may include a display device 10_4 and a reflective member 40. The image displayed on the display device 10_4 is reflected by the reflective member 40 and provided to the user's right eye via the right eye lens 10b. This allows the user to view the virtual reality image displayed on the display device 10_4 through their right eye.

[0205] Figure 29 shows that the display device housing 50 is located at the right end of the support frame 20, but the embodiments herein are not limited to this. For example, the display device housing 50 can be located at the left end of the support frame 20, in which case the image displayed on the display device 10_4 can be reflected by the reflective member 40 and provided to the user's left eye via the left eye lens 10a. This allows the user to view the virtual reality image displayed on the display device 10_4 through their left eye. Alternatively, the display device housing 50 can be located at both the left and right ends of the support frame 20, in which case the user can view the virtual reality image displayed on the display device 10_4 through both their left and right eyes.

[0206] Figure 30 is an illustrative diagram showing the instrument panel and center fascia of a vehicle including a display device according to one embodiment. Figure 30 shows an automobile to which display devices 10_a, 10_b, 10_c, 10_d, and 10_e according to one embodiment are applied.

[0207] Referring to Figure 30, one embodiment of the display devices 10_a, 10_b, and 10_c can be applied to the dashboard of a car, to the center fascia of a car, or to a CID (Center Information Display) located on the dashboard of a car. In addition, one embodiment of the display devices 10_d and 10_e can be applied to a rearview mirror display that replaces the side mirrors of a car.

[0208] Figure 31 is an illustrative diagram showing a transparent display device including a display device according to one embodiment.

[0209] Referring to Figure 31, a display device 10_5 according to one embodiment can be applied to a transparent display device. A transparent display device can display video IM while simultaneously transmitting light. Therefore, a user positioned in front of the transparent display device can not only view the video IM displayed on the display device 10_5, but also see objects RS or the background located behind the transparent display device. When the display device 10_5 is applied to a transparent display device, the substrate of the display device 10_5 can include a light-transmitting portion that can transmit light, or it can be formed from a light-transmitting material.

[0210] Although preferred embodiments of the present invention have been described above with reference to them, a person skilled in the art or a person with ordinary knowledge of the art will understand that the present invention can be modified and altered in various ways without departing from the spirit and technical domain of the invention as described in the claims below.

[0211] Therefore, the technical scope of the present invention is not limited to what is described in the detailed description of the specification, but should be defined by the claims. [Explanation of Symbols]

[0212] 100 Display Panels 10 Circuit boards TDU Transfer Mechanism 210 First conveyor head 220 Second transport head 230 stamps 250 Air injection member 251 Spray head LE light-emitting element

Claims

1. First transport head and A second conveying head is positioned below the first conveying head, A stamp positioned below the second transport head, An inclination adjustment member for adjusting the inclination of the second transport head, A light-emitting element transfer apparatus, comprising: an air supply member that injects air downward from one surface of the second transport head to form an air layer.

2. The aforementioned air supply member is An air supply unit that supplies air, An injection head is positioned on one side of the second conveying head and has holes through which air is injected, The light-emitting element transfer apparatus according to claim 1, further comprising an injection line that penetrates the second transport head and connects the air supply unit and the injection head.

3. The light-emitting element transfer apparatus according to claim 2, wherein the hole is either of a single-hole type or a porous type.

4. The light-emitting element transfer apparatus according to claim 2, wherein the air supply unit is an air pump.

5. The light-emitting element transfer apparatus according to claim 1, wherein the first transport head has a cavity with an inlet facing downward, and the width of the inlet is smaller than the width of the cavity.

6. The light-emitting element transfer apparatus according to claim 5, wherein the second transport head is divided into a first part disposed within the cavity, a third part disposed outside the first transport head, and a second part disposed between the first part and the third part, and the width of the second part is narrower than the width of the first part and the second part.

7. The light-emitting element transfer apparatus according to claim 6, wherein the tilt adjustment member includes a first permanent magnet disposed on the first transport head and a second permanent magnet disposed on the first part of the second transport head, facing the first permanent magnet and having a repulsive force with the first permanent magnet.

8. The light-emitting element transfer apparatus according to claim 1, wherein the second transport head has a chuck on one side and uses the chuck to adsorb a stamp.

9. The light-emitting element transfer apparatus according to claim 5, wherein the second transport head is divided into a first part disposed within the cavity, a third part disposed outside the first transport head, a second part disposed between the first part and the third part, and an inclined part disposed between the first part and the second part, the width of the second part being narrower than the widths of the first and second parts.

10. The light-emitting element transfer apparatus according to claim 9, wherein the tilt adjustment member includes a plurality of second permanent magnets arranged in the first part and the tilted part, and a plurality of first permanent magnets arranged on the first transport member so as to correspond to the plurality of second permanent magnets.

11. The light-emitting element transfer apparatus according to claim 1, further comprising a pressurizing member disposed between the first and second transport heads within the cavity of the first transport head, which pressurizes the second transport head downward.

12. The light-emitting element transfer apparatus according to claim 11, wherein the pressurizing member is a spring.

13. The light-emitting element transfer apparatus according to claim 11, wherein the pressurizing member includes an elastic membrane placed on the second conveying head within the cavity of the first conveying head, a gas pipe connected between the elastic membrane and the cavity, and a gas supply member that supplies gas to the gas pipe.

14. The light-emitting element transfer apparatus according to claim 1, wherein the first transport head, the second transport head, and the tilt adjustment member are air gyros.

15. The air supply member includes an injection head having a hole through which air is injected, The light-emitting element transfer apparatus according to claim 1, wherein the injection heads are arranged discontinuously in a plurality around the stamp.

16. The air supply member includes an injection head having a hole through which air is injected, The light-emitting element transfer apparatus according to claim 1, wherein the spray heads are arranged continuously around the stamp.

17. The steps of placing the transfer mechanism described in claim 1 onto a substrate, The air supply member forms an air layer between the second transport head and the substrate, and the transfer mechanism is lowered in a step - the thickness of the air layer is greater than the sum of the height of the stamp and the height of the light-emitting element - A step of adjusting the flatness of the transfer mechanism to match the flatness of the substrate, The second transport head is lowered downward, and the air layer is pressurized to bring the light-emitting element into contact with the substrate and transfer it—the thickness of the air layer is the same as the sum of the height of the stamp and the height of the light-emitting element— A method for transferring light-emitting elements, including the method described above.

18. In the step of placing the transfer mechanism on the substrate, A method for transferring light-emitting elements according to claim 17, wherein a light-emitting element placed on the stamp is aligned on the substrate based on a first alignment key placed on one surface of the stamp and a second alignment key placed on the substrate.

19. In the step of adjusting according to the flatness of the substrate, The method for transferring light-emitting elements according to claim 17, wherein the tilt adjustment member adjusts the second transport head to match the flatness of the substrate while the second transport head is not in contact with the first transport head.

20. In the step where the air supply member forms an air layer between the second transport head and the substrate and lowers the transfer mechanism, The method for transferring a light-emitting element according to claim 17, wherein an air supply unit supplies air to an injection head along an injection line, and the injection head injects air downward to form an air layer.

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