KR20230034647A - Apparatus and method for repairing micro light-emitting diode using vcsel - Google Patents

Abstract

The present invention relates to an apparatus for repairing micro light-emitting diodes (LEDs) using a vertical cavity surface emitting laser (VCSEL). A micro LED repair device using a VCSEL according to an embodiment of the present invention comprises: a scan module for scanning a panel containing at least one defective micro LED; a VCSEL module including at least one VCSEL which emits a laser to release a bond between the defective micro LED and the panel or to bond a new micro LED; a lifting module which removes the debonded defective micro LED from the panel and moves the new micro LED to a location at which the defective micro LED was removed; and a processor which adjusts the irradiation conditions of the VCSEL module based on the scan result. The present invention can prevent the new micro LED from being damaged due to excessive irradiation.

Description

Micro LED repair device and method using vixel {APPARATUS AND METHOD FOR REPAIRING MICRO LIGHT-EMITTING DIODE USING VCSEL}

The present invention relates to a repair device for a micro light-emitting diode (LED) using a vertical cavity surface emitting laser (VCSEL).

Recently, interest in a direct light emitting type (or self light emitting type) display using a micro light-emitting diode (LED) is increasing. A direct light emitting display using micro LEDs requires a transfer process of placing a plurality of micro LEDs on a substrate (or panel). However, it is very difficult to transfer a micro LED having a very small size (eg, 100 micrometers or less) onto a substrate. For example, when an LED is transferred to an incorrect location, it may not emit light or the intensity of light may be weak. In addition, even if it is transferred to the correct position, it may not emit light due to a defect in the LED itself. Accordingly, various transfer methods (eg, transfer using an interposer, roll transfer using a stamp, transfer using electrostatic force, transfer using a fluidic assembly, etc.) have been developed.

However, currently known transcription methods have poor yields. Accordingly, interest in a repair device and process (method) for repairing a substrate including a defective micro LED (eg, replacing a defective LED with a new micro LED) is increasing. However, due to the very small size, it is very difficult to selectively remove only the defective micro LED from the substrate and bond the new micro LED. Accordingly, there is a need for a repair device and method capable of easily and efficiently removing defective micro LEDs from a substrate and bonding new micro LEDs.

Accordingly, an object of the present invention is to solve the above problems, and to use a vertical cavity surface emitting laser (VCSEL) to easily remove only defective micro LEDs and to bond new micro LEDs to a micro LED using a vertical cavity surface emitting laser (VCSEL). It is to provide an LED repair device and method.

Another object of the present invention is to scan a panel (or substrate) including a plurality of micro LEDs and to provide a big cell capable of adjusting (eg, optimizing) the irradiation conditions of the big cells for removing defective micro LEDs based on the scan results. It is to provide a repair device and method for a micro LED using the same.

A micro LED repair device using a vixel of the present invention to achieve the above object includes a scan module for scanning a panel including at least one defective micro LED; a vixel module including at least one vixel irradiating a laser to release the bond between the defective micro LED and the panel or to bond a new micro LED; a lifting module that removes the defective micro LED from which the bond is released from the panel and moves the new micro LED to a location from which the defective micro LED is removed; and a processor adjusting an irradiation condition of the big cell module based on the scan result.

In addition, the micro LED repair method using the big cell of the present invention includes the steps of scanning a panel including at least one defective micro LED; adjusting an irradiation condition of a big cell module including the big cell based on the scan result; controlling the big cell module to irradiate a laser under the adjusted irradiation condition based on the position of the defective micro LED; removing defective micro LEDs from the panel by irradiation of the laser; and bonding a new micro LED to a location where the defective micro LED is removed.

As described above, according to the present invention, only the defective micro LED can be effectively removed by uniformly irradiating the laser to the region where the defective micro LED is mounted using the big cell.

According to the present invention, high power can be provided by arranging vixels in multiple rows and combining lasers output from at least some of the vixels arranged in multiple rows. In addition, according to the present invention, a plurality of defective micro LEDs can be simultaneously removed by using vixels arranged in multiple rows, and a plurality of new micro LEDs can be simultaneously bonded.

In the present invention, irradiation conditions of big cells can be adjusted (optimized). For example, the defective micro LED can be efficiently removed by adjusting the irradiation conditions of the vixel based on the location, size and/or thickness of the defective micro LED, and micro LEDs located around the defective micro LED due to excessive irradiation. can be prevented (or prevented) from being damaged. In addition, the present invention can prevent the new micro LED from being damaged due to excessive irradiation by adjusting the irradiation conditions optimized for bonding of the new micro LED.

1 is a block diagram showing the configuration of a repair device according to an embodiment of the present invention.
2A is a diagram for explaining a method of irradiating a big cell according to an embodiment of the present invention.
2B is a diagram for explaining a method of irradiating a big cell according to another embodiment of the present invention.
3 is a diagram for explaining irradiation conditions of a big cell according to an embodiment of the present invention.
4 is a diagram showing the configuration of a big cell module according to another embodiment of the present invention.
5 is a flowchart illustrating a micro LED repair method using a big cell according to an embodiment of the present invention.

Objects and effects of the present invention, and technical configurations for achieving them will become clear with reference to embodiments described later in detail in conjunction with the accompanying drawings. In describing the present invention, if it is determined that a detailed description of a known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description will be omitted.

In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of a user or operator.

However, the present invention is not limited to the embodiments disclosed below and may be implemented in a variety of different forms. Only these embodiments are provided to complete the disclosure of the present invention and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined by the scope of the claims. only become Therefore, the definition should be made based on the contents throughout this specification.

1 is a block diagram showing the configuration of a repair device according to an embodiment of the present invention, FIG. 2a is a diagram for explaining a method of irradiating a big cell according to an embodiment of the present invention, and FIG. 2b is a diagram of the present invention It is a diagram for explaining a method of irradiating a big cell according to another embodiment, and FIG. 3 is a diagram for explaining a condition for irradiating a big cell according to an embodiment of the present invention.

1 to 3, a micro LED repair device 100 using a vixel according to an embodiment of the present invention uses a vixel (vertical cavity surface emitting laser), which is a type of laser diode, to repair a defective micro LED ( A substrate (or panel) including a light emitting diode may be repaired. For example, the repair device 100 uses a vixel to heat a defective micro LED or an area where the defective micro LED is located to release the bonding between the defective micro LED and the substrate (eg, an adhesive material (eg, ACF (eg, ACF)). melting anisotropic conductive film), ACA (anisotropic conductive adhesive), ACP (anisotropic conductive paste), SAP (self-assembly anisotropic conductive paste), solder, low-viscosity solder (8,000 ~ 12,000 cps)), and removing A device (eg, the lifting module 130 ) may be used to remove the defective micro LED from the substrate, and a new micro LED may be bonded to the region from which the defective micro LED is removed. To this end, the repair device 100 may include a scan module 110, a big cell module 120, a lifting module 130, and a processor 140.

The scan module 110 may scan a substrate to be repaired. The scan module 110 may be a camera. For example, the scan module 110 may image a substrate. According to some embodiments, the scan module 110 may further include various sensors capable of checking the arrangement, spacing, and location, size, and/or thickness of defective micro LEDs. According to another embodiment, the scan module 110 may further include a sensor capable of checking the characteristics of the substrate (thickness, thermal conductivity) and/or the characteristics of the bonding material (eg, melting temperature). According to another embodiment, some information (eg, characteristics of a substrate, characteristics of a bonding material, thickness of a micro LED) may be input by a user.

The big cell module 120 may include at least one big cell that converts electrical signals into lasers and emits them in a direction perpendicular to the upper surface.

The big cell module 120 may irradiate a laser beam to the defective micro LED or the substrate in order to release the bonding between the defective micro LED and the substrate (eg, melting the bonding material) or to bond a new micro LED to the substrate. For example, as shown in FIG. 2A , the big cell module 120 may irradiate a laser onto the defective micro LED 201 mounted on the top surface of the substrate 200 from the top of the substrate 200. . As another example, as shown in FIG. 2B , the big cell module 120 radiates laser to a partial area corresponding to the position of the defective micro LED 201 on the lower surface of the substrate 200 at the bottom of the substrate 200 . can do.

The big cell module 120 may be moved based on the position of the defective micro LED or the new micro LED. In the big cell module 120 according to an embodiment of the present invention, irradiation conditions (eg, irradiation period, delay time, and intensity) may be adjusted based on the scan result of the scan module 110 under the control of the processor 140. there is.

According to some embodiments, the big cell module 120 may have an array structure in which a plurality of big cells are arranged in multiple rows. In the case of having the array structure, the big cell module 120 may simultaneously irradiate laser to a plurality of defective micro LEDs (or new micro LEDs). Through this, when the big cell module 120 has an array structure, the repair device 100 can more quickly repair a substrate including a plurality of defective micro LEDs.

According to an embodiment, the big cell module 120 may irradiate a high-power laser by combining lasers output from a plurality of big cells. A detailed description thereof will be described later with reference to FIG. 4 .

The lifting module 130 may remove the defective micro LED and move a new micro LED to the corresponding position. For example, as shown in FIGS. 2A and 2B , the lifting module 130 adsorbs (vacuum-sucks) the defective micro LED 201 so that the bonding with the substrate 200 is released. ) can be removed from the substrate 200. After removing the bad micro LED, the lifting module 130 may adsorb the new micro LED and move it to the area where the bad micro LED is removed.

Meanwhile, it is only an example that the lifting module 130 moves a defective micro LED or a new micro LED by a suction method, and the lifting module 130 may move a defective micro LED or a new micro LED using various known methods. .

The processor 140 may control overall operations of the repair device 100 . For example, the processor 140 may control the scan module 110 to photograph the substrate and analyze the image captured through the scan module 110 to check the array of micro LEDs mounted on the substrate. Also, the processor 140 may check the location, size, and thickness of the defective micro LED. According to some embodiments, the processor 140 may check the characteristics of the substrate (thickness, thermal conductivity) and/or the characteristics of the bonding material (melting temperature).

The processor 140 may adjust irradiation conditions (or irradiation parameters) of the big cell module 120 based on the scan result of the scan module 110 . For example, as shown in FIG. 3, the processor determines the irradiation time (on period) 301 and the delay time (off period) 302 of the pulse signal for controlling driving of the big cell module 120. ) and intensity (amplitude) 303 may be adjusted. Specifically, the processor 140 determines the intensity of the laser (e.g., the on-period, off-period, and/or amplitude of the pulse signal) according to the arrangement, spacing, and location, size, and/or thickness of the defective micro-LEDs. can be properly controlled. As another example, the processor 140 may adjust irradiation conditions according to the characteristics of the substrate (thickness, thermal conductivity) and the bonding material (eg, melting temperature). For example, the processor 140 may irradiate the laser from the lower part of the substrate and increase the irradiation time or amplitude of the pulse signal when the thickness of the substrate is thick or the thermal conductivity is low. In addition, the processor 140 may lengthen the irradiation time or increase the amplitude of the pulse signal when the micro LED is bonded to the substrate with a bonding material having a relatively high melting temperature. Here, the irradiation time 301 is a parameter for controlling the temperature rise, and the longer the irradiation time 301, the higher the temperature. The delay time 302 is a parameter for controlling the decrease in temperature, and the longer the delay time 302, the lower the temperature. A desired temperature can be maintained by appropriately adjusting the irradiation time 301 and the delay time 302. Meanwhile, the intensity 303 is a parameter that controls the speed of temperature rise, and the higher the intensity 303, the area where the micro LED is attached. It is possible to rapidly increase only the surface temperature of , because if the temperature rises slowly, heat may be transferred to the inside of the micro LED and damage may occur to the micro LED.

The processor 140 may set an irradiation condition for removing a defective micro LED and an irradiation condition for bonding a new micro LED differently. For example, the processor 140 may adjust an irradiation condition of the big cell module 120 set to another irradiation condition in order to remove a defective micro LED before bonding a new micro LED. In detail, the processor 140 may adjust irradiation conditions according to the characteristics (eg, melting temperature) of the bonding material confirmed by the scan module 110 or the user.

The processor 140 controls the lifting module 130 to remove the bad micro LED from the substrate, and controls the lifting module 130 and the big cell module 120 to bond a new micro LED to the location where the bad micro LED is removed. can A detailed description thereof will be described later with reference to FIG. 5 .

Meanwhile, in FIG. 2A , the big cell module 120 is illustrated as radiating a laser obliquely from the side of the defective micro LED 201, but the big cell module 120 may irradiate the laser perpendicularly to the defective micro LED 201. . In this case, the big cell module 120 may be integrally configured with the lifting module 130.

4 is a diagram showing the configuration of a big cell module according to another embodiment of the present invention.

Referring to FIG. 4 , the big cell module 420 according to another embodiment of the present invention may emit a high-power laser. To this end, the big cell module 420 may include a big cell array 421, a micro lens array 422, a focus lens 423, an optical fiber cable 424, and a cooler 425.

The big cell array 421 may include a plurality of big cells arranged in multiple rows (arranged in an array structure).

The micro lens array 422 may include a plurality of micro lenses arranged in multiple rows. For example, the micro lens array 422 may include a plurality of micro lenses arranged in the same array structure as the big cell array 421 . According to some embodiments, the micro lens array 422 may be integrated into the big cell array 421 .

The focus lens 423 may condense lasers output from the micro lens array 422 . For example, as shown in FIG. 4 , the focus lens 423 may condense all lasers emitted from the micro lens array 421 in 4 rows and 4 columns. According to some embodiments, the big cell module 420 may include a plurality of focus lenses. For example, assuming that the big cell array 421 and the micro lens array 422 have an array structure of 4 rows and 4 columns and condense laser light emitted from the micro lenses of 2 rows and 2 columns, the big cell module 420 ) may include four focus lenses.

The optical fiber cable 424 may move the laser condensed by the focus lens 423 . For example, the optical fiber cable 424 may move a concentrated high-power laser so that it may be irradiated to a defective micro LED to be removed or a new micro LED to be bonded.

The cooler 425 may dissipate heat generated in the big cell module 420 to the outside. The cooler 425 may be a fan. Although not limited thereto, various coolers 425 may have various shapes (eg, heat sinks). According to some embodiments, the cooler 425 may not be included in the big cell module 420 .

The big cell module 420 having the above-described array structure can output a high-output laser, thereby increasing the surface temperature in a shorter time and minimizing heat conduction to the inside.

5 is a flowchart illustrating a micro LED repair method using a big cell according to an embodiment of the present invention.

Referring to FIG. 5 , a micro LED repair method using a big cell according to an embodiment of the present invention includes scanning a panel including at least one defective micro LED (501). For example, the processor of the repair device may scan the panel by controlling a scan module (eg, a camera).

A repair method according to an embodiment of the present invention includes adjusting an irradiation condition of a big cell module including a big cell based on a scan result (503). For example, the processor of the repair device analyzes the image scanned by the scan module to determine the arrangement and spacing of the micro LEDs mounted on the panel, the size and thickness of the micro LEDs, the characteristics of the substrate (eg thickness, thermal conductivity), and bonding. The characteristics of the material (eg, melting temperature) may be recognized, and the irradiation conditions of the big cell module may be adjusted based on the recognition result. That is, the processor may optimize the irradiation conditions of the big cell module so as to remove only defective micro LEDs from the panel while not affecting or minimizing the bonding of the surrounding normal micro LEDs. The irradiation condition may include an on/off time and amplitude of a pulse signal that controls driving of the big cell module.

The repair method according to an embodiment of the present invention includes controlling the big cell module to irradiate laser with the adjusted irradiation condition based on the location of the defective micro LED (505). For example, the processor of the repair device may move the big cell module based on the location of the defective micro LED and control the big cell module to irradiate laser only to a partial area (top or bottom) of the panel where the defective micro LED is located.

The repair method according to an embodiment of the present invention includes removing defective micro LEDs from which bonding with the panel has been released (507). For example, the processor of the repair device may control the lifting module to remove the defective micro LED from the substrate by vacuum suction.

The repair method according to an embodiment of the present invention includes bonding a new micro LED to a location where the defective micro LED is removed (509). For example, the processor of the repair device vacuum-sucks a new micro LED through a lifting module, moves it to a location where the defective micro LED is removed, and irradiates a laser through a big cell module to bond the new micro LED to the panel. According to an embodiment, the processor may adjust the irradiation condition of the big cell module adjusted in step 503 to an irradiation condition optimized for bonding of the new micro LED in order to remove the defective micro LED.

On the other hand, although not shown in FIG. 5, before moving the new micro LED to the position where the bad micro LED is removed, a bonding material is stamped on the electrode of the new micro LED or bonded to the panel where the bad micro LED is removed. It includes the step of attaching the material.

The repair device described above with reference to FIGS. 1 to 5 can easily remove only defective micro LEDs by using a vixel among known laser diodes. This is because the vixel uniformly emits a laser beam as a surface light source, and the laser beam has a size similar to that of a micro LED (eg, about 30 to 40 micrometers). On the other hand, edge emitting laser (EEL) diodes do not uniformly emit laser beams and have a smaller size (about 10 micrometers) than micro LEDs. The used repair device has a complicated structure because it additionally requires a lens for concentrating the laser beam, and has the inconvenience of increasing manufacturing cost.

In addition, in general, a vixel has a lifespan that is about 50 times longer than that of a side-emitting laser diode. Therefore, the maintenance cost of the repair device according to an embodiment of the present invention is lower than that of a repair device using a side-emitting laser diode.

In addition, the repair device according to an embodiment of the present invention can optimize the irradiation conditions of the big cell module based on the board scan result, so that other micro LEDs in the vicinity are repaired (removal of bad micro LEDs and bonding of new micro LEDs). It does not affect the LED, or the effect can be minimized.

In addition, the repair apparatus according to an embodiment of the present invention may arrange a plurality of big cells in a multi-column array structure, and may emit a high-power laser by combining a plurality of big cells. For this reason, the repair device according to an embodiment of the present invention can instantaneously generate heat by irradiating a high-output laser beam on the area where the defective micro LED is located, and can easily remove only the defective micro LED. In contrast, since side-emitting laser diodes can be arranged only in rows, a repair device using side-emitting laser diodes has difficulty in providing high output.

Although the above has been described with reference to the illustrated embodiments of the present invention, these are only examples, and those skilled in the art to which the present invention belongs can variously It will be apparent that other embodiments that are variations, modifications and equivalents are possible. Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.

100: repair device
110: scan module 120: big cell module
130: lifting module 140: processor

Claims (11)

In the repair device of a micro light-emitting diode (LED) using a vertical cavity surface emitting laser (VCSEL),
a scan module that scans a panel including at least one defective micro LED;
a vixel module including at least one vixel irradiating a laser to release the bond between the defective micro LED and the panel or to bond a new micro LED;
a lifting module that removes the unbonded defective micro LED from the panel and moves the new micro LED to a position where the defective micro LED is removed; and
and a processor for adjusting an irradiation condition of the big cell module based on the scan result.
According to claim 1,
The scan result is
The device characterized in that it comprises at least one of the location, size and thickness of the defective micro LED.
According to claim 1,
The big cell module
Irradiate a laser based on a pulse signal,
The processor
Apparatus characterized in that for adjusting at least one of the on time, off time, and amplitude of the pulse signal.
According to claim 1,
The big cell module
A device characterized in that it includes a plurality of vixels arranged in multiple rows.
According to claim 4,
The processor
The apparatus characterized in that driving a big cell corresponding to a location of the defective micro LED among the plurality of big cells based on the adjusted irradiation condition.
According to claim 4,
a micro lens array in which a plurality of micro lenses are arranged in multiple rows to correspond to the plurality of vix cells;
a focus lens condensing the lasers output from the micro lens array; and
The apparatus of claim 1, further comprising an optical fiber cable for moving the condensed laser so that the condensed laser is irradiated to the defective micro LED.
According to claim 1,
The processor
The apparatus characterized in that the irradiation condition of the big cell module is adjusted to another irradiation condition before bonding the new micro LED.
According to claim 1,
The device, characterized in that arranged to irradiate the laser to the upper surface of the defective micro LED, or to irradiate the laser to the lower surface of the panel to which the defective micro LED is bonded.
In the repair method of a micro light emitting diode (LED) using a vertical cavity surface emitting laser (VCSEL),
scanning the panel including at least one defective micro LED;
adjusting an irradiation condition of a big cell module including the big cell based on the scan result;
controlling the big cell module to irradiate a laser under the adjusted irradiation condition based on the position of the defective micro LED;
removing defective micro LEDs from the panel by irradiation of the laser; and
and bonding a new micro LED to a location where the defective micro LED is removed.
According to claim 9,
The scanning step is
Scanning at least one of the location, size, and thickness of the defective micro LED;
Adjusting the irradiation conditions of the big cell module
and adjusting at least one of an on time, an off time, and an amplitude of a pulse signal that controls driving of the big cell module.
According to claim 9,
The method further comprising adjusting an irradiation condition of the big cell module to another irradiation condition before bonding the new micro LED.

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