KR102624389B1 - Apparatus and method for repairing micro LED display - Google Patents

Abstract

The present invention relates to a micro LED display repair device and method, and more specifically, to a micro LED display repair device and method that can repair defects in a micro LED display that cannot be repaired with conventional repair devices.
The micro LED display repair device of the present invention supplies a stage for holding a micro LED display including a micro LED chip and a circuit pattern for driving the micro LED chip, and a laser to remove defective portions of the micro LED display. It includes a laser source and an optical module that irradiates the laser generated from the laser source by changing the path to remove a preset area in order to repair defective areas of the micro LED display, wherein the optical module The preset area is removed to a depth where the lower circuit pattern of the micro LED display, which supplies power required for operation to the micro LED chip, is revealed.
According to the micro LED display repair device and method of the present invention, defects in the micro LED display that cannot be repaired by conventional repair methods can be repaired, and in order to repair the defective LED chip, a certain area is removed and then repaired through cleaning. The success rate can be maximized, and a simple repair is possible by removing or disabling the defective LED chip and then mounting a normal LED chip through ink.

Description

Micro LED display repair device and method {Apparatus and method for repairing micro LED display}

The present invention relates to a repair device and method for repairing a defective micro LED display. More specifically, devices for repairing defects occurring in conventional LCD and OLED displays repair defective areas by cutting or connecting the circuit pattern of the TFT array, but the micro LED display of the present invention is suitable for micro LED displays rather than the conventional method. The present invention relates to a repair device and method for repairing a micro LED display by removing a defective micro LED chip and installing a normally operating micro LED chip.

Recently, flat panel displays such as LCD and OLED, commonly known as FPD (Flat Panel Display), are widely used as displays for TVs and smartphones. However, not only LCD but also OLED have many disadvantages, so research is being actively conducted on displays using micro LED, and micro LED displays with large areas and ultra-high resolution are gradually becoming popular.

There are various shortcomings in the case of LCD and OLED. LCD has limitations in color reproduction, and does not emit light on its own, so it requires a light source such as a backlight, making it difficult to implement in a thin form and difficult to implement in a flexible display. OLED has various advantages such as color reproduction and perfect contrast ratio, but it has a fatal problem called burn-in (afterimage).

Micro LED is a display that can solve all the problems of conventional LCD and OLED and displays images by arranging very small LED chips. Recently, as the size of LED chips can be manufactured very small, it is possible to achieve almost the same resolution as that of LCD and OLED displays. Unlike LCD, self-luminous light is possible, there is no problem such as burn-in of OLED, and the luminance is lower than that of LCD and OLED displays. It is in the spotlight as a next-generation display.

During display manufacturing, defects in which pixels do not turn on or off due to various foreign substances occur. When such defects occur, the entire display must be discarded due to defects, which increases the manufacturing cost. In order to reduce manufacturing costs and defect rates, a repair process to repair defects is essentially included in the manufacturing process.

Conventionally, the defect rate has been lowered through a repair process that repairs defects caused by foreign substances, etc. during the FPD manufacturing process. In the conventional repair process, if the wires included in the FPD are short-circuited, the short-circuited part is cut with a laser, or if the wire is broken, the short-circuited part is cut with a laser. It was performed as a process to connect broken wiring using a metal source and laser.

This conventional repair process was carried out by repairing defects occurring in the TFT array that corresponds 1:1 to the pixel. In addition to these defects, in the case of micro LED displays, the LED chip itself corresponding to the pixel does not operate. There are also defects, and these defects cannot be repaired using conventional repair processes.

The present invention is intended to solve the above problems and provides a micro LED display repair device and method that can repair defects in a micro LED display that cannot be repaired with conventional repair devices.

In order to achieve the above object, the micro LED display repair device of the present invention includes a stage for holding a micro LED display including a micro LED chip and a circuit pattern for driving the micro LED chip, and a defective device among the micro LED displays. A laser source that supplies a laser to remove an area, and an optical module that irradiates the laser generated from the laser source by changing the path to remove a preset area in order to repair the defective area of the micro LED display. Including, the optical module is characterized in that it is removed to a depth where the lower circuit pattern of the micro LED display, which supplies power required for operation to the micro LED chip, is revealed in the preset certain area.

In addition, the circuit pattern includes a driving line that drives the micro LED chip and an extra auxiliary line, and a preset area to be removed by the optical module is an area where a defective micro LED element is located or a defect in the micro LED display. It is characterized in that it is the area where the auxiliary line is closest to the micro LED element.

In addition, the optical module further includes a cleaning module for cleaning foreign substances remaining after removing defective areas in the micro LED display by irradiating a laser.

In addition, the cleaning module is characterized by an air blower method that blows a preset gas to remove foreign substances remaining in the defect area.

In addition, the optical module is characterized by including a scanner that changes the laser path to irradiate the laser supplied from the laser source to the defective part of the micro LED display.

In addition, the optical module further includes a mounting module that removes a defective portion of the micro LED display and then mounts a normally operating micro LED chip on the removed portion.

Additionally, the mounting module further includes an ink module that sprays conductive ink onto the lower circuit pattern to mount a normal micro LED chip on the exposed lower circuit pattern after being removed from the optical module.

In addition, in order to achieve the above object, the micro LED display repair method of the present invention includes the steps of moving a micro LED display including a micro LED chip and a circuit pattern for driving the micro LED chip to a stage; A step of removing a certain area by changing the path of a laser supplied from a laser source to remove a defective part of the micro LED display through an optical module and radiating it to the micro LED display; It includes the step of mounting a normal LED chip in a certain area removed through the optical module.

In addition, in the step of removing the predetermined area, the optical module is removed to a depth where the lower circuit pattern of the micro LED display, which supplies power required for operation to the micro LED chip, is revealed for the predetermined area to be removed.

In addition, in the step of removing the predetermined area, the circuit pattern includes a driving line for driving a micro LED chip and an extra auxiliary line, and the predetermined area to be removed by the optical module is a defective micro LED display. It is characterized by being the area where the LED element is located or the area where the auxiliary line is closest to the defective micro LED element.

In addition, the step of removing a predetermined area through the optical module and then cleaning foreign substances remaining in the predetermined area through a cleaning module is further included.

In addition, in the cleaning step, the cleaning module is cleaned using an air blower method that blows a preset type of gas to remove foreign substances remaining in the defect area.

Additionally, in the step of mounting the normal LED chip, the mounting module uses conductive ink on the upper part of the lower circuit pattern through the ink module to mount the normal micro LED chip on the lower circuit pattern exposed after being removed by the optical module. It further includes the step of spraying.

The present invention configured as described above has the effect of repairing defects in a micro LED display that cannot be repaired using conventional repair methods.

In addition, in order to repair a defective LED chip, a certain area can be removed and cleaned to maximize the success rate of the repair.

In addition, there is an effect of performing optimized repair for the micro LED display by removing or disabling the defective LED chip and then mounting a normal LED chip through ink.

1 is a perspective view of a micro LED display repair device according to an embodiment of the present invention;
Figure 2 is a diagram showing the process of removing a certain part and then cleaning it using the micro LED display repair device of the present invention.
Figure 3 is a diagram showing the process of rendering the micro LED to be repaired inoperable through the micro LED display repair device of the present invention;
Figure 4 is a diagram showing an example of a circuit pattern of the micro LED display of the present invention;
Figure 5 is a diagram showing the process of mounting the micro LED display repair device of the present invention through a mounting module;
Figure 6 is a diagram showing a cross section of the micro LED display after the repair of the present invention is performed;
Figure 7 is a flowchart showing the micro LED display repair method of the present invention.

Hereinafter, the micro LED display repair device and method according to the present invention will be described in detail with reference to the drawings.

Figure 1 is a perspective view of a micro LED display repair device according to an embodiment of the present invention, Figure 2 is a diagram showing the process of cleaning after removing a certain portion through the micro LED display repair device of the present invention, and Figure 3 is a view showing the process of cleaning the micro LED display repair device according to an embodiment of the present invention. It is a diagram showing the process of rendering the micro LED to be repaired inoperable through the micro LED display repair device of the invention, Figure 4 is a diagram showing an example of a circuit pattern of the micro LED display of the invention, and Figure 5 is a diagram showing an example of a circuit pattern of the micro LED display of the invention. It is a diagram showing the process of mounting through the mounting module of the LED display repair device, Figure 6 is a diagram showing a cross section of the micro LED display after repair of the present invention, and Figure 7 is a micro LED display repair method of the present invention. This is a flow chart representing .

Until recently, LCD and OLED were the representative displays for FPD, but as explained earlier, LCD is not self-luminous, so it requires a light source such as a backlight, and due to the limitations of the backlight, a curved display with a certain degree of curvature is possible, but foldable There is a problem that it cannot be applied to flexible displays, and in the case of OLED, self-luminescence is possible, but there is a problem of low durability, such as burn-in, due to the use of organic light-emitting materials. Because of these problems with FPDs such as conventional LCDs and OLEDs, micro LED displays that are capable of self-emitting and do not have problems such as burn-in are attracting attention.

Conventional FPDs produce defective pixels due to foreign substances during the manufacturing process and essentially include a repair process to ensure that these defective pixels operate normally. In order to solve the problem of pixels not operating normally due to foreign substances during the FPD manufacturing process, the main process is a cutting process that cuts off the wiring that connects the circuit pattern when a disconnection occurs due to foreign substances and a short circuit occurs. achieve As an example shown in FIG. 4, the micro LED display also has a circuit pattern at the bottom, such as a driving line (DL) and an auxiliary line (AL) for use as a spare when the driving line (DL) does not operate, and the micro LED The conventional repair process can be applied as is to the circuit pattern board. The micro LED display is a form in which very small LED chips are mounted as many as the number of pixels, and its composition is different from that of a conventional FPD, so a repair method other than the conventional repair process is required, and the present invention is a repair method specialized for such micro LED displays. It relates to devices and methods.

The micro LED repair device of the present invention holds a micro LED display at the top to repair a micro LED display with a circuit pattern including a micro LED chip and a driving line (DL) and auxiliary line (AL) for driving the chip. In order to repair the defective part of the stage 100 and the micro LED display, the laser source 200 supplies a laser to remove a certain part, and the path of the laser supplied from the laser source 200 is changed to irradiate the defective part. It includes an optical module 300 that does. As described above, a micro LED display is constructed by mounting LED chips on a circuit pattern, and after mounting the LED chips, a protective film 20 is usually formed to protect the display. This protective film 20 can be of various types, but it must of course be made of a transparent material and must be durable enough to prevent damage to the mounted LED chip. As an example of the protective film 20, ACF (Anisotropic Conductive Film), which is an anisotropic conductive film that conducts electricity in only one direction, can be used. The main reason for using ACF, an anisotropic conductive film, is to protect the LED chip mounted on the board, but the fine conductive particles in ACF also have the effect of strengthening the connection between the LED chip and the circuit of the board. When removing a certain area of the micro LED display through the optical module 300, it is desirable to process it to a depth where circuit patterns such as the driving line (DL) and auxiliary line (AL) provided under the protective film 20, such as the ACF, are revealed. . This is because electrical connection to the driving line (DL) or auxiliary line (AL) is required when mounting a normal LED chip on a circuit pattern. In Figure 6, both the drive line (DL) and the auxiliary line (AL) are shown to be electrically connected. However, this is done by removing and connecting the part where the drive line (DL) is located, and by removing and connecting the part where the auxiliary line (AL) is located. It expresses all connections, so there is no problem in operation even if connected to either circuit line. However, as described above, the abnormal micro LED can be removed to reveal the circuit pattern, but as shown in FIG. 3, a certain part of the abnormal micro LED is cut to prevent the abnormal micro LED from operating, and then an auxiliary circuit is installed. Repair can also be performed by mounting a normal micro LED on the pattern. Of course, compared to the method of completely removing the abnormal micro LED and then mounting the normal micro LED, it cannot be said to be a very precise repair because the mounting position of the micro LED is different from the original, but there is a gap between the original location of the micro LED and the auxiliary circuit pattern. Since this is not large, there is no significant difference in the repair effect, the cleaning process is easy, and there are almost no by-products in the removal process, so there is an advantage that repair can be performed more efficiently. Of course, there are pros and cons, so it is advisable to make a decision considering the environment in which the repair will be performed.

In addition, not only when removing a certain part of the micro LED display by irradiating a laser through the laser source 200 and the optical module 300, but also when inactivating abnormal micro LEDs, a process of mounting normal LED chips is required. In order to remove the foreign matter (F) remaining on the circuit pattern, it further includes a cleaning module (400) for cleaning the foreign matter (F) and a mounting module (500) for mounting a normal LED chip after cleaning. This is desirable in that the repair process can be completed in one go with the equipment.

The stage 100 of the present invention is configured to hold and fix a micro LED display on the top to perform a repair process of the micro LED display. The size of the stage 100 is preferably configured according to the size of the micro LED display to be repaired. It is configured to use sound pressure to prevent the display from moving during the repair process, or to be transparent for lighting when lighting is needed at the bottom. Of course, the detailed configuration of the stage 100 can be configured in various ways depending on the repair process environment.

The laser source 200 of the present invention is configured to supply laser to perform a repair process. The laser supplied from the laser source 200 may be a CW laser or a pulse type depending on the characteristics of the micro LED display to be repaired. In addition, it is desirable to use an appropriate wavelength range of the laser for the efficiency of the removal process, and the same applies to the output of the laser.

The optical module 300 of the present invention changes the path of the laser supplied from the laser source 200 to irradiate it to an appropriate location to repair defects. The optical module 300 is generally composed of a number of mirrors and lenses. A method uses a scanner that directly irradiates the laser supplied from the laser source 200 to the micro LED display, and a method uses an objective lens with an appropriate focal length. It can be broadly divided into: The method using a scanner has the advantage of simplifying the configuration of the optical module 300 and enabling quick path changes by directly irradiating the laser. However, if an image module to photograph the repair process is additionally configured, the laser irradiation process and image acquisition are separate. Since it consists of a configuration, it has the disadvantage of being cumbersome to match the coordinate system and difficult to organically control the repair process. The method of using multiple mirrors and objective lenses has the disadvantage of complicating the configuration, but since the optical system for laser irradiation and the optical system for image taking can be processed in one configuration, laser irradiation and image taking can be performed within one coordinate system. It has the advantage of being able to handle the repair process organically. Any method can be applied to the repair process of a micro LED display, and it is advisable to decide taking into account the environment and characteristics of the repair process.

The optical module 300 removes the part to be repaired by irradiating a laser to the defective micro LED display. As described above, the micro LED display is a board with a circuit pattern on the bottom and an LED chip is mounted on the board to protect it. It consists of a protective film (20) for. In order to remove the protective film 20 of the micro LED display and mount the normal LED chip 10, the optical module 300 removes the protective film 20 to a depth D at which the circuit pattern is revealed at the bottom. Conventionally, a process of applying metal and sintering with a laser was performed to break or connect circuit patterns, but in the case of micro LED displays, repair is done through the process of mounting LED chips, so a protective film (not a process to break or connect circuit patterns) is used. The process of removing 20) to the depth (D) where the circuit pattern is revealed is essential. Of course, in the case of inactivating an abnormal micro LED, it is not necessary to process it to a depth where the circuit pattern is revealed, but a process of cutting the abnormal micro LED to the point where it does not operate is necessary.

Additionally, the optical module 300 can directly remove a portion of a micro LED display containing a defective LED chip or remove a portion of an auxiliary line (AL) to be used as an extra driving line (DL). If you directly remove the defective part, you must also remove the LED chip that is not operating normally, which has the disadvantage of making the removal process complicated and creating a large amount of foreign matter. However, it has the advantage of not requiring a process to disable the LED chip that is not operating normally. When removing the area where the auxiliary line (AL) is located, a process to disable the LED chip that does not operate normally is required, but since only the protective film 20 is removed, the removal process has the advantage of being easy.

The cleaning module 400 of the present invention is configured to remove and clean foreign substances (F) from the area removed through the optical module 300. When removing the protective film 20, etc. using a laser, foreign matter (F) generated during the removal process may exist in the removed area, and this foreign matter (F) may cause poor contact with the circuit pattern when mounting the normal LED chip 10. It is advisable to perform a cleaning process as this may cause damage.

The cleaning module 400 can use a cleaning solution or an air blower method that blows cleaning gas. Although the cleaning effect is excellent, a separate configuration for recovering the cleaning solution must be prepared, and the cleaning method requires a separate method to recover the cleaning solution. Since the repair process is carried out in a room environment, the cleaning process and post-processing can be very difficult. In the case of the air blow method, the cleaning effect may be lower than that of the method using a cleaning liquid, but the cleaning process is very simple and the configuration of the cleaning module 400 can be simplified. The gas used for cleaning can be selected depending on the composition of the protective film 20 of the micro LED display, and it is preferable to use carbon dioxide to maximize the cleaning effect.

The mounting module 500 of the present invention includes a process of removing the protective film 20 in a certain area through the optical module 300, removing foreign substances (F) on the circuit pattern through the cleaning module 400, and then mounting the LED chip. It is a configuration that is performed. In order to mount an LED chip, as an example of the mounting module 500 of the present invention, conductive ink such as silver (Ag) is sprayed onto the driving line (DL) or auxiliary line (AL) through the nozzle unit 510. Use the spray method. When using the ink injection method, there is an advantage in that electrical contact between the LED chip and the circuit pattern can be established very simply and a small amount of ink can be accurately sprayed onto the circuit pattern with a very fine width. It is desirable to use an EHD (electrohydrodynamics) ink injection method to properly spray a small amount of ink at the correct location. Of course, the mounting module 500 may include a transfer module that accurately positions the normal LED chip 10 at the location where the ink is sprayed, as well as a configuration for ink injection. In addition, of course, a configuration of applying a protective film 20 after mounting the normal LED chip 10 as shown in FIG. 5 may be further included.

Hereinafter, the micro LED display repair method of the present invention will be described with reference to FIG. 7, but redundant description will be omitted.

In the micro LED display repair method of the present invention, the micro LED display to be repaired for defects containing the micro LED chip and the circuit pattern for driving the chip is moved to the stage 100 and fixed through suction, etc. (S100). The laser supplied from the laser source 200 to the micro LED display fixed to the stage 100 is redirected through the optical module 300 to irradiate the defective area of the micro LED display and remove the area (S110). A normal LED chip is mounted in a certain area removed through the optical module 300 (S120).

Stage: 100 Laser Source: 200
Optical module: 300 Cleaning module: 400
Mounting module: 500

Claims (13)

In a repair device for repairing defects in a micro LED display,
A stage for holding a micro LED display including a micro LED chip and a circuit pattern for driving the micro LED chip,
a laser source that supplies laser to remove defective portions of the micro LED display;
It includes an optical module that irradiates the laser generated from the laser source by changing its path to remove a preset area in order to repair defective areas of the micro LED display,
The optical module irradiates a laser to the upper part of the micro LED display, and removes the preset certain area to a depth that exposes the lower circuit pattern of the micro LED display that supplies power required for operation to the micro LED chip. Micro LED display repair device.
In claim 1,
The circuit pattern includes a driving line that drives the micro LED chip and an extra auxiliary line,
A micro LED display repair device, characterized in that the preset area to be removed by the optical module is the area where the defective micro LED element is located or the area where the auxiliary line closest to the defective micro LED element is located in the micro LED display. .
In claim 1,
A micro LED display repair device further comprising a cleaning module for cleaning foreign substances remaining after the optical module removes defective areas within the micro LED display by irradiating a laser.
In claim 3,
The cleaning module is a micro LED display repair device characterized in that it is an air blower type that blows a preset gas to remove foreign substances remaining in the defect area.
In claim 1,
The optical module is a micro LED display repair device characterized in that it includes a scanner that changes the laser path to irradiate the laser supplied from the laser source to the defective part of the micro LED display.
In claim 1,
A micro LED display repair device further comprising a mounting module that removes a defective portion of the micro LED display from the optical module and then mounts a normally operating micro LED chip on the removed portion.
In claim 6,
The mounting module is a micro LED display repair device further comprising an ink module that sprays conductive ink on the upper part of the lower circuit pattern to mount a normal micro LED chip on the lower circuit pattern exposed after being removed from the optical module.
In the method of repairing defects in a micro LED display,
Moving a micro LED display including a micro LED chip and a circuit pattern for driving the micro LED chip to the stage;
A step of removing a certain area by changing the path of a laser supplied from a laser source to remove a defective part of the micro LED display through an optical module and radiating it to the micro LED display;
Including the step of mounting a normal LED chip through a mounting module in a certain area removed through the optical module,
In the step of removing the certain area,
The optical module irradiates a laser from the upper part of the micro LED display, and removes a certain area to be removed to a depth where the lower circuit pattern of the micro LED display, which supplies power necessary for operation to the micro LED chip, is revealed. How to repair a micro LED display.
delete In claim 8,
In the step of removing the certain area,
The circuit pattern includes a driving line that drives the micro LED chip and an extra auxiliary line,
A micro LED display repair method, wherein the predetermined area to be removed by the optical module is an area of the micro LED display where a defective micro LED element is located or an area where an auxiliary line closest to the defective micro LED element is located.
In claim 8,
A micro LED display repair method further comprising removing a predetermined area through the optical module and then cleaning foreign matter remaining in the predetermined area using a cleaning module.
In claim 11,
In the cleaning step,
A micro LED display repair method, characterized in that the cleaning module is cleaned using an air blower method that blows a preset type of gas to remove foreign substances remaining in the defect area.
In claim 8,
In the step of mounting the normal LED chip,
Micro LED display repair further comprising the step of spraying conductive ink on the upper part of the lower circuit pattern through an ink module in order to mount a normal micro LED chip on the lower circuit pattern exposed after the mounting module is removed by the optical module. method.