Transfer method

Abstract

To provide a transfer method capable of manufacturing an LED display suppressed in color shading within a short time by a simple method.SOLUTION: This transfer method transfers light-emitting elements on a plurality of panels from one donor by using a donor having the plurality of light-emitting elements exhibiting prescribed colors, the panels on which the light-emitting elements are mounted, transfer means for transferring the light-emitting elements from the donor to the panels, position control means for controlling the relative positions of the donor, the panels, and the transfer means, storage means for storing the position information of the light-emitting elements transferred onto the donor and the panels and light emission waveforms of the light-emitting elements, and calculation means for calculating the order of the relative positions in order to transfer the prescribed number of light-emitting elements to the panels. Transferring of the light-emitting element to a next panel is carried out after completion of transferring of the prescribed number of light-emitting elements to one panel. On a panel to which first transferring is carried out, a light-emitting element having a light emission wavelength within a partial range of the range of light emission wavelengths usable for transferring is selected and mounted.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a transfer method. [Background technology]

[0002] In recent years, development of displays using LEDs as an alternative to conventional liquid crystal displays has been progressing, and commercialization is progressing. Displays using LEDs like this (LED displays) are FHD (Full High Definition) panels with 1920 x 1080 red, green, and blue LEDs, and 3840 x 2160 for 4K panels, each densely mounted on a wiring board in a grid-like arrangement.

[0003] As the color LEDs densely mounted on the wiring board in this way, so-called micro LEDs having minute dimensions of, for example, about 50 μm × 50 μm are used. As shown in Patent Document 1, such micro LEDs are obtained through a process of epitaxially growing gallium nitride crystals on a growth substrate such as sapphire, and are diced into chips of the above dimensions on the substrate. The LED chips thus formed are transferred from the growth substrate to the wiring board, which is a display, through one or more transfer processes. After that, the LED chips are fixed to the wiring board through a mounting process such as thermocompression bonding.

[0004] There are several methods for transferring an LED chip to a wiring substrate that is a display panel. For example, a method using laser ablation technology disclosed in Patent Documents 2 and 3 is known.

[0005] Patent Document 2 discloses a method for transferring elements (LED chips) using laser ablation technology. In addition, there are individual differences in the emission wavelengths of multiple LED chips formed on one growth substrate, but Patent Document 3 discloses a transfer method that prevents viewers from noticing color unevenness caused by individual differences in emission wavelengths when manufacturing an LED display. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2002-170993 A [Patent Document 2] JP 2006-41500 A [Patent Document 3] JP 2022-135521 A Summary of the Invention [Problem to be solved by the invention]

[0007] The invention disclosed in Patent Document 3 was created to solve a new problem of preventing color unevenness from occurring on an LED display while utilizing the invention disclosed in Patent Document 2. However, in the invention disclosed in Patent Document 3, after measuring all of the light-emitting characteristics of each LED chip on one growth substrate (wafer), a transfer simulation is first performed to prevent color unevenness from occurring on the display panel while taking into account the light-emitting characteristics of all of the LED chips, and then actual transfer is performed, which means that the simulation for transfer takes a very long time, and the transfer device has to wait a long time before the actual transfer can be performed.

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a transfer method that can manufacture an LED display with reduced color unevenness in a short period of time using a simple method. [Means for solving the problem]

[0009] The transfer method of the present invention is a transfer method for transferring light-emitting elements from one donor to multiple panels by changing the relative positions multiple times in each of the panels using a donor on which a plurality of light-emitting elements exhibiting a predetermined color are arranged in a plane, a panel on which the light-emitting elements are transferred from the donor and mounted, a transfer means for transferring the light-emitting elements from the donor to the panel, a position control means for controlling the relative positions of the donor, the panel, and the transfer means, a memory means for storing position information of the light-emitting elements in the donor, position information of the transferred light-emitting elements in the panel, and the emission wavelength of each of the light-emitting elements, and a calculation means for calculating the order of the relative positions to transfer a predetermined number of the light-emitting elements to the panel using the data stored in the memory means, characterized in that after the transfer of the predetermined number of the light-emitting elements to one panel is completed, the light-emitting elements are transferred to the next panel, and the panel on which the transfer is performed first has a light-emitting element having an emission wavelength within a partial range of the emission wavelength range that can be used for transfer selected and mounted thereon.

[0010] The partial range of emission wavelengths may include an average value of the emission wavelengths of the light-emitting elements in the donor. Effect of the Invention

[0011] When transferring light-emitting elements from one donor to multiple panels, by using only light-emitting elements with a limited range of emission wavelengths within the range of emission wavelengths that can be used for transfer, i.e., a narrow wavelength range, for the first panel, there is no need to take care to avoid color unevenness, and the transfer simulation can be shortened, thereby shortening the standby time of the transfer device and improving manufacturing efficiency. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a schematic diagram of a transfer device for a light emitting element according to an embodiment. [Diagram 2]3A and 3B are schematic diagrams showing an example of the relative positional relationship between a donor, a transfer unit, a transfer region, and a panel according to the embodiment. [Diagram 3] (A) is an example showing the area of ​​the donor relative to the transcribed region, (B) the transcribed region, and (C) the area of ​​the panel relative to the transcribed region. [Figure 4] (A) is another example showing the area of ​​the donor relative to the transcribed region, (B) the transcribed region, and (C) the area of ​​the panel relative to the transcribed region. [Diagram 5] (A) is another example showing the area of ​​the donor relative to the transcribed region, (B) the transcribed region, and (C) the area of ​​the panel relative to the transcribed region. [Figure 6] 1 is a diagram showing an emission wavelength distribution of a light-emitting element that exhibits green light and is present in a donor according to an embodiment. FIG. [Figure 7A] FIG. 13 is a diagram showing the calculation time and transfer time when a transfer method to which the present invention is not applied is used. [Figure 7B] FIG. 11 is a diagram showing calculation time and transfer time when a transfer method to which the present invention is applied is used. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Before describing the mode for carrying out the invention, the inventors of the present application will explain how they came up with and created the present invention.

[0014] Micro LEDs (light-emitting devices) are manufactured through processes such as epitaxial growth of gallium nitride crystals on a growth substrate (wafer) such as sapphire, and exist as numerous chips on a single wafer. In this growth process, it is extremely difficult to achieve uniform processing at every position on a single wafer, regardless of the processing step, including gallium nitride crystal growth. As a result, the characteristics of each completed chip are slightly different and vary. Of these characteristics, the emission wavelength is particularly important for displays.

[0015] The above-mentioned variations are often caused by temperature variations in the manufacturing equipment that manufactures micro LEDs and uneven supply of raw materials, and when multiple wafers are processed at once using one manufacturing equipment, unevenness occurs depending on the position of the wafer. As a result, for example, the characteristic values ​​change between the center and periphery of the wafer, or between the right and left sides, or in stripes, resulting in unevenness.

[0016] It is extremely difficult to avoid unevenness in characteristic values, especially in emission wavelength, among the many chips on one wafer. Therefore, for example, it is not uncommon for unevenness to occur, such as light-emitting elements in the center having longer emission wavelengths while light-emitting elements in the periphery have shorter emission wavelengths, but panels are manufactured on the assumption that such unevenness exists.

[0017] Generally, one wafer contains a large number of chips (light-emitting elements), and one wafer can supply light-emitting elements to multiple panels. Although panels usually have a larger surface area than wafers, the distance between chips on a panel is much greater than the distance between chips on a wafer, so the number of light-emitting elements on one wafer is greater than the number of light-emitting elements mounted on one panel.

[0018] In addition, the area that can be transferred at one time by a transfer device that transfers light-emitting elements from a wafer to a panel is small compared to the area of ​​the entire wafer or panel, so in order to transfer all the light-emitting elements required for one panel, it is necessary to move the wafer and panel multiple times to the transfer area to perform the transfer.

[0019] Furthermore, in order to reduce the manufacturing cost of the panel, it is important to reduce the number of movements and transfers. To achieve this, it is possible to transfer as many light-emitting elements on the wafer as possible in the transfer area to the panel, and if possible, to transfer all of the light-emitting elements that can be transferred. In this case, it is possible that as many light-emitting elements as possible are transferred from the center of the wafer to a specific area on the panel, and as many light-emitting elements as possible are transferred from the peripheral area of ​​the wafer to the adjacent area. If there is unevenness such that there is a large difference in the emission wavelength of the light-emitting elements between the center and peripheral areas of the wafer as described above, light-emitting elements with long emission wavelengths will be transferred intensively to a specific area on the panel, and light-emitting elements with short emission wavelengths will be transferred intensively to the adjacent area, resulting in a clear difference in emission wavelength, i.e., color unevenness, between the two adjacent areas.

[0020] The invention disclosed in Patent Document 3 is an invention for preventing such color unevenness, but it measures and stores the emission wavelength of each light-emitting element, and controls the transfer based on that to prevent color unevenness. The calculation time required for the transfer to prevent color unevenness, the time and number of movements of the wafer and panel, and the time and number of transfers are enormous, and the time required to transfer the light-emitting elements to the panel becomes very long. The inventors of the present application conducted various studies in consideration of such a situation and came up with the present invention.

[0021] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present invention, its application, or its uses.

[0022] (Embodiment 1) The first embodiment relates to a transfer method for transferring a large number of micro LED chips from a donor (wafer) on which chips are arranged side by side in a plane to a panel substrate that will become a display panel by a transfer means. The transfer means uses laser lift-off (laser ablation technology), but other methods may also be used.

[0023] 1, the donor 20 has a plurality of light-emitting elements 22 arranged in a plane, and is held by a holding means 25 and faces a panel 30. The panel 30 has a surface opposite to the surface on which the light-emitting elements 22a are transferred, and is suction-held by a mounting unit 32, which is placed on a moving stage 42. The holding means 25 may be a growth substrate that serves as a base for epitaxially growing chips, or an intermediate substrate attached to a wafer.

[0024] The transfer means 10 includes a laser light source 11, a galvanometer mirror 12, and an Fθ lens 14. The laser light source 11 is a device that emits one laser beam 13. Examples of lasers that can be used include a YAG laser, a visible light laser, and an ultraviolet laser. The galvanometer mirror 12 has two mirrors, and by controlling the positions and angles of these mirrors, it emits the incident light beam in any direction.

[0025] The transfer is performed as follows. A pulsed laser beam 13 emitted from a laser light source 11 is irradiated onto the holding means 25 via a galvanometer mirror 12 and an Fθ lens 14. The laser beam 13 passes through the holding means 25 and reaches the interface between the holding means 25 and the light-emitting element 22, causing laser ablation at this interface. Due to this laser ablation, the light-emitting element 22 is peeled off from the holding means 25 and biased downward, and is transferred onto the panel 30. The light-emitting element that has already been transferred onto the panel 30 is denoted by the reference symbol 22a.

[0026] In the transfer means, the optical path of laser light 13 is controlled by galvanometer mirror 12 to irradiate various positions on holding means 25, but the range of change in the position and angle of galvanometer mirror 12 is limited. Therefore, as shown in FIG. 2, in the transfer means 10, transfer area 15, which is an area that can be irradiated with laser light 13, has an area smaller than that of donor 20 and panel 30.

[0027] As described above, since the total number of light-emitting elements 22a mounted on a panel 30 is generally considerably smaller than the total number of light-emitting elements 22 on one donor (wafer) 20, it is possible to transfer the light-emitting elements 22 from one donor 20 to multiple panels 30. Therefore, even if the required number of light-emitting elements 22a are mounted on the panel 30 shown in Fig. 1, if there are a sufficient number of light-emitting elements 22 on the donor 20, the panel 30 on the mounting portion 32 is replaced with a new one and transfer is performed.

[0028] (Placement Step) Since the transfer region 15 has a small area compared to the donor 20 and the panel 30, in order to transfer the required number of light-emitting elements 22a onto the entire surface of the panel 30, it is necessary to change the relative positions of the transfer region 15, the donor 20, and the panel 30 and perform the transfer each time. Since the transfer means 10 is a large-scale device and is fixed, the position of the donor 20 is controlled by the gripping means 41 that grips the holding means 25, and the position of the panel 30 is controlled by the moving stage 42. The donor 20 and the panel 30 are moved parallel to the surface of the panel 30 to which the light-emitting elements 22a are transferred by the position control means equipped with the gripping means 41 and the moving stage 42, and the relative positions of the transfer region 15, the donor 20, and the panel 30 change. The donor 20 and the panel 30 are moved and positioned by the position control means so that a selected predetermined position (region) faces the transfer region 15.

[0029] (Examination of transcription at a certain relative position) 3, in (A), a plurality of light-emitting elements 22 are arranged adjacent to each other with gaps (small intervals) in between in the area of ​​the donor 20 facing the transfer area 15, whereas in (C), light-emitting elements 22a are transferred to an area of ​​the panel 30 facing the transfer area 15 at intervals larger (several times to several tens of times) than the adjacent intervals between the light-emitting elements 22 in the donor 20. In the transfer area 15, transferable positions 16 are set at intervals the same as the transfer intervals of the panel 30, as shown in (B).

[0030] In FIG. 3, since the light-emitting elements 22 are lined up on the donor 20 without any gaps, it is possible to transfer the light-emitting elements 22 to the panel 30 using all of the transferable positions 16 in the transfer area 15. This improves the transfer efficiency, but if this method is continued, obvious color unevenness may appear on the panel 30.

[0031] In order to prevent the color unevenness when the panel 30 emits light as described above, the inventors of the present application conducted studies using various parameters and performed simulations, and discovered that it is possible to control the transfer means 10 so that only a portion of the transferable positions 16 is used, rather than using all of them.

[0032] Specifically, when a light-emitting element 22 exhibiting a predetermined color (e.g., green) that exists in one donor 20 is transferred to a panel 30, if the emission wavelength of the light-emitting element 22 exhibiting the predetermined color (green) is within a range of 535 nm to 539 nm, the human eye perceives the color as exactly the same green, and therefore, when a light-emitting element 22 having an emission wavelength outside this range is located at a transferable position 16, control is performed so that the transferable position 16 is not used for transfer. However, such control cannot be performed unless there are a sufficient number of light-emitting elements 22 with emission wavelengths within the range of 535 nm to 539 nm in the donor 20. Therefore, in this embodiment, such control is performed when an unused donor 20 is used for the first panel 30, and a different control is performed for the second and subsequent panels 30.

[0033] (Transfer step) 3, 4 and 5, there are nine transferable positions 16 in the transfer area 15. Until the transfer of all light-emitting elements 22a to the panel 30 is completed, it is more efficient and the transfer is completed more quickly if all available transferable positions 16 are used to perform the transfer. An available transferable position 16 is a state in which a light-emitting element 22 exists at a position on the donor 20 corresponding to the transferable position 16, and a light-emitting element 22 has not been transferred to a position on the panel 30 corresponding to the transferable position 16.

[0034] For example, in the state shown in Fig. 3, a large number of light-emitting elements 22 are present in the transfer area of ​​the donor 20, and it is possible to transfer a large number (9 in Fig. 3) of light-emitting elements 22 to the panel 30 by using all of the transferable positions 16 in the transfer area 15, thereby improving the transfer efficiency. However, as described above, when transfer is performed in this manner, color unevenness due to light emission on the panel 30 caused by variations in the emission wavelengths of the multiple light-emitting elements 22 in the donor 20 may become evident.

[0035] Therefore, taking into consideration the emission wavelength of the light-emitting element 22, it was decided to not use some of the available transferable positions 16 in the transfer area 15 for transfer (transfer at the next opportunity or later). For example, as shown in Fig. 4, of the nine transferable positions 16 corresponding to the light-emitting element 22, the transferable positions not used for transfer (non-transfer portions 18) are set to four, and only five light-emitting elements 22 are transferred. Conversely, as shown in Fig. 5, even if there is only one transferable position 16 corresponding to the light-emitting element 22, the transferable position not used for transfer (non-transfer portion 18) is set to zero, so that all the transferable light-emitting elements 22 (one in Fig. 5) that can be transferred are controlled to be transferred.

[0036] (Transfer to first panel) In a process for manufacturing a plurality of display panels by transferring light-emitting elements 22 from one donor 20 to a plurality of panels 30, all the light-emitting elements 22 required for one panel 30 are transferred before the light-emitting elements 22 are transferred to the next panel 30. In this embodiment, the method of controlling the transfer of the light-emitting elements 22 to the first panel 30 is different from the method of controlling the transfer to the second and subsequent panels 30. The method of controlling the transfer of the light-emitting elements 22 to the first panel 30 will be described below.

[0037] FIG. 6 is a histogram showing the distribution of the emission wavelengths of the light-emitting elements 22 in the donor 20 and their frequency (number). The light-emitting elements 22 that emit green light are created in this donor 20. The light-emitting elements 22 are manufactured under conditions set so that the emission wavelengths of the light-emitting elements 22 are within the range of 535 nm to 539 nm, but in reality, the emission wavelengths vary within the range of 530 nm to 547 nm as shown in FIG. 6. The average emission wavelength of all the light-emitting elements 22 in the donor 20 is within the range of 535 nm to 539 nm. If the emission wavelengths of the two light-emitting elements 22 are within the range of 535 nm to 539 nm (the range from reference numeral 61 to reference numeral 62, hatched), humans do not recognize a difference in color even if the two emission wavelengths are slightly different. That is, humans recognize that light with an emission wavelength of 535 nm and light with an emission wavelength of 539 nm are the same color when comparing them. On the other hand, when comparing light with an emission wavelength of 530 nm with light with a wavelength of 539 nm, or light with an emission wavelength of 535 nm with light with a wavelength of 547 nm, a person may perceive the colors as different.

[0038] For this reason, the transfer of the light-emitting elements 22 to the first panel 30 is performed using only the light-emitting elements 22 with an emission wavelength in the range of 535 nm to 539 nm. By adopting such a transfer control method, the light-emitting elements 22 having an emission wavelength in a specific range are selected from the donor 20 to perform a transfer simulation, and it is not necessary to use other elements, such as the transfer position on the panel 30, the corresponding position of the light-emitting elements 22 in the donor 20, and the selection of the light-emitting elements 22 taking into consideration the emission wavelength so as not to cause color unevenness, as control parameters. Therefore, the calculation time for the transfer simulation of all the light-emitting elements 22 that need to be mounted on the panel 30 before the actual transfer can be shortened compared to the case where there are many control parameters (transfer simulation to the second and subsequent panels).

[0039] If the calculation time for the transfer simulation onto the first panel 30 can be reduced, the manufacturing time for the display panel can be reduced, leading to reduced manufacturing costs.

[0040] (Transfer to the second and subsequent panels) When transferring the light-emitting elements 22 to the second and subsequent panels 30, all the remaining light-emitting elements 22 in the donor 20 are used for transfer because there is a risk of there being a shortage of light-emitting elements 22 with an emission wavelength in the range of 535 nm to 539 nm, and because manufacturing costs increase if light-emitting elements 22 with emission wavelengths other than 535 nm to 539 nm are not used. For this reason, a transfer simulation is performed as follows.

[0041] The light emitting element 22 with an emission wavelength in the range of 535 nm to 539 nm (within the range from reference numeral 61 to reference numeral 62) can be transferred as it is, regardless of the transfer position on the panel 30. However, for the light emitting element 22 with an emission wavelength outside the range of 535 nm to 539 nm, the transfer position is limited. For example, when a plurality of light emitting elements 22 (reference numeral 53 in FIG. 6) having an emission wavelength of 547 nm are transferred adjacent to each other on the panel 30, the portion may look different in color from the area where the light emitting elements 22 in the range of 535 nm to 539 nm are transferred, that is, the portion may look uneven in color. On the other hand, a plurality of light emitting elements 22 (usually several to several tens of light emitting elements) are mounted in a one-time viewing range (a circle on the display panel with a viewing angle of 1 degree for an observer who observes the display panel at a predetermined distance), but when this one-time viewing range is observed, the observer cannot distinguish the difference in the emission wavelength of each light emitting element 22, and instead observes the color due to the average emission wavelength of the light emitting elements 22 mounted in the one-time viewing range.

[0042] Therefore, if a transfer simulation is performed so that the average emission wavelength of the light-emitting elements 22 transferred once within the field of view falls within the range of 535 nm to 539 nm, and actual transfer is performed accordingly, color unevenness will not occur over the entire panel 30. Alternatively, if the light-emitting element 22 having the shortest emission wavelength of 530 nm (reference numeral 52) and the light-emitting element 22 having the longest emission wavelength of 547 nm (reference numeral 53) in Fig. 6 are always transferred adjacent to each other, it will be perceived that these two elements emit light of the average wavelength of 538.5 nm (within the range of 535 nm to 539 nm), and therefore the light-emitting elements 22 with reference numerals 52 and 53 may always be transferred adjacent to each other in a pair.

[0043] In this method of determining the transfer positions by pair, after all the transfer positions of the light-emitting elements 22 with emission wavelengths of 530 nm, reference numeral 52, and 547 nm, reference numeral 53, are determined, a transfer simulation is then performed using the light-emitting elements 22 with emission wavelengths of 531 nm, reference numeral 54, and 546 nm, reference numeral 55, so that they are similarly arranged side by side. The average of these two emission wavelengths is 538.5 nm, which is within the range (allowable range) of 535 nm to 539 nm.

[0044] In FIG. 6, the number of light emitting elements 22 with an emission wavelength of 531 nm indicated by reference numeral 54 is greater than the number of light emitting elements 22 with an emission wavelength of 546 nm indicated by reference numeral 55. Therefore, after all the light emitting elements 22 with an emission wavelength of 546 nm have been transferred, a simulation is performed so that the light emitting elements 22 with an emission wavelength of 545 nm indicated by reference numeral 57 and the light emitting elements 22 with an emission wavelength of 531 nm indicated by reference numeral 54 are combined and placed next to each other. The average of these two emission wavelengths is 538 nm, which is also within the range of 535 nm to 539 nm (the allowable range of color unevenness). In this way, by including all the light emitting elements 22 on the donor 20 that have emission wavelengths other than the range of 535 nm to 539 nm as the transfer target, the yield of the light emitting elements 22 can be increased and the cost can be reduced.

[0045] (Calculation time and transcription time) The calculation time of the transfer simulation using the transfer method according to the present embodiment and the transfer time for actual transfer are shown in Fig. 7B. Fig. 7A shows the calculation time and transfer time when the transfer method according to the comparative example is used, specifically, when the transfer of the light-emitting elements 22 to the first panel is performed with all the light-emitting elements 22 on the donor 20 as the transfer targets, and when the transfer simulation is performed so as not to cause color unevenness on the display panel.

[0046] 7A of the comparative example and FIG. 7B of the present embodiment, the calculation time 71a of the transfer simulation to the first panel of A is longer than the calculation time 71b of the transfer simulation to the first panel of B, and these times are equal to the stop times 80a, 80b of the transfer device. Therefore, the stop time of the transfer device is shorter in the present embodiment than in the comparative example, and the time to create multiple display panels from one donor 20 can be shortened accordingly.

[0047] Since the performance of computers has improved year by year, the time required for actually performing the transfer based on the simulation is longer than the calculation time for the transfer simulation. Therefore, for both A and B, the calculation times 72a and 72b for the transfer simulation to the second panel are completed within the transfer times 81a and 81b for the first panel, so that the transfer to the second panel (transfer times 82a and 82b, respectively) can be performed without the need to stop the transfer device. It should be noted that the calculation of the simulation can be performed for the next panel immediately after the calculation of one panel is completed. Therefore, once the transfer simulation to the second panel is completed, the transfer simulation to the third panel (calculation times 73a and 73b, respectively) can be performed consecutively.

[0048] In the transfer to the second and subsequent panels of this embodiment, the calculation time is longer than that of the transfer simulation to the first panel because the calculation is performed taking into account the emission wavelength during the transfer simulation as described above. However, when comparing the time required for the calculation of the transfer simulation with the time required for the actual transfer according to the simulation, if the calculation time of the simulation is shorter than the actual transfer time as shown in Figures 7A and 7B, the calculation of the transfer simulation to the second panel is completed while the light-emitting element 22 is actually transferred to the first panel 30, so the calculation time of the transfer simulation to the second panel does not affect the manufacturing time. On the other hand, since the time of the transfer simulation to the first panel 30 is directly reflected in the manufacturing time, by performing a simulation of transferring the light-emitting element 22 to the first panel 30 using only the light-emitting element 22 having an emission wavelength close to the average emission wavelength of the light-emitting element 22 present in the donor 20 as in this embodiment, the calculation time of the simulation is shortened, thereby shortening the manufacturing time and reducing the manufacturing cost.

[0049] (Other embodiments) The above-mentioned embodiments are merely examples of the present invention, and the present invention is not limited to these examples, and these examples may be combined with well-known, commonly used, or publicly known technologies, or may be partially replaced. In addition, modified inventions that can be easily conceived by a person skilled in the art are also included in the present invention.

[0050] The range of emission wavelengths of the light emitting elements 22 transferred to the first panel 30 may be determined according to the predetermined color exhibited by the light emitting elements 22, specifications, and the like.

[0051] In the first simulation of transfer onto panel 30 in embodiment 1, only the range of emission wavelengths of the light-emitting element 22 was limited, but additional parameters such as the transfer position onto panel 30 and the corresponding position of the light-emitting element 22 within the donor 20 may also be used.

[0052] When performing a transfer simulation onto the second panel 30, if there are a sufficient number of light-emitting elements 22 remaining in the same emission wavelength range as used for transfer onto the first panel 30, and using only the light-emitting elements 22 in that emission wavelength range for transfer onto the second panel 30 does not excessively lengthen the calculation time for the transfer simulation onto the third or subsequent panels 30 or the actual transfer time, then only the light-emitting elements 22 in the same emission wavelength range as used for transfer onto the first panel 30 may be used for transfer onto the second panel 30. [Explanation of symbols]

[0053] 10 Transfer Method 15 Transcription area 16 Transferable positions 20 Donors 22 Light emitting element 22a Light emitting element (transferred onto the panel) 30 Panel

Claims

1. a donor on which a plurality of light-emitting elements exhibiting a predetermined color are arranged in a plane; a panel on which the light-emitting elements are transferred from the donor and mounted; a transfer means for transferring the light-emitting elements from the donor to the panel; a position control means for controlling respective relative positions of the donor, the panel, and the transfer means; a storage means for storing position information of the light-emitting elements in the donor, position information of the transferred light-emitting elements in the panel, and an emission wavelength of each of the light-emitting elements; and a calculation means for calculating an order of the relative positions in order to transfer a predetermined number of the light-emitting elements to the panel by using the data stored in the storage means, After the predetermined number of the light-emitting elements have been transferred to one of the panels, the light-emitting elements are transferred to a next panel; A transfer method characterized in that the panel on which transfer is performed first is equipped with a light-emitting element having an emission wavelength within a partial range of the range of emission wavelengths that can be used for transfer.

2. The method of claim 1 , wherein the partial range of emission wavelengths includes an average emission wavelength of the light-emitting element in the donor.

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