TWI824328B - Apparatus and method for repairing micro led display - Google Patents

Abstract

The present invention provides a device and method for repairing defects of a micro LED display. The repair device of the micro LED display includes a pedestal to accommodate the micro LED display. The micro LED display includes a micro LED chip and a device for driving the micro LED chip. circuit pattern; a laser light source to provide laser light to remove defective parts of the micro LED display; an optical module to change the path of the laser light generated from the laser light source and irradiate the laser light to remove the predetermined A specific area is provided in order to repair the defective part of the micro LED display, wherein the optical module removes the preset specific area to a depth to expose the circuit pattern on the lower part of the micro LED display, the The circuit pattern is used to provide the power required for operation of the micro LED chip. According to the present invention with the above structure, the effect of repairing defects in micro LED displays that cannot be repaired by traditional repair methods can be achieved.

Description

Device and method for repairing micro LED displays

The present invention relates to devices and methods for repairing defective micro-LED displays. In more detail, conventional equipment for repairing defects in LCD and OLED displays repairs defective parts by cutting or connecting circuit patterns of TFT arrays. However, the device and method for repairing micro-LED displays of the present invention are different from the conventional methods. The present invention is suitable for micro-LED displays, that is, the repair method is to remove defective micro-LED chips and install normal-working micro-LED chips.

In recent years, flat-panel displays such as LCD and OLED, often referred to as flat panel displays (FPD), have become widely used as displays in televisions and smartphones. However, both LCD and OLED have many shortcomings, so research on displays using micro-LEDs is actively being carried out, and micro-LED displays that achieve large areas and ultra-high resolution are gradually becoming popular.

In LCD and OLED displays, there are various disadvantages. LCD displays have limitations in color reproducibility, and they are not self-illuminating and therefore require a light source such as a backlight. Therefore, LCD displays have problems in that they are difficult to implement in a thin form and are difficult to implement as flexible displays. Although OLED displays have various advantages, such as color reproduction and perfect contrast, there is a fatal problem of burn-in (after-image).

Micro LED displays are displays that can solve all the problems of traditional LCD and OLED displays by arranging very small LED wafers to display images. Recently, since the size of LED wafers can be made very small, micro-LED displays can achieve almost the same resolution as LCD and OLED displays, and unlike LCD displays can be self-luminous, without problems such as OLED aging, brightness and LCD , OLED displays are better than OLED displays and are attracting people's attention as the next generation display.

During the display manufacturing process, defects in which pixels cannot be turned on/off may occur due to various foreign matter factors. When such defects occur, the entire display must be discarded due to the defect, increasing manufacturing costs. In order to reduce manufacturing costs and defect rates, the repair process to repair defects is basically included in the manufacturing process.

In the past, defect rates were reduced by repairing defects caused by foreign matter during FPD manufacturing. In the traditional repair process, when the wires contained in the FPD are short-circuited, the short-circuited part is cut with laser light, or when the wire is disconnected, a metal source and laser light are used to connect the disconnected wires.

These conventional repair processes are performed in a manner that repairs defects occurring in the TFT array corresponding to pixels 1:1. In addition to these defects, in the case of micro-LED displays, there are also defects in which the LED chips corresponding to the pixels themselves do not work, but such defects have problems that cannot be repaired by traditional repair processes.

"Technical Problems to be Solved"

In order to solve the above-mentioned problems, the present invention provides a device and method for repairing micro-LED display defects that cannot be repaired by traditional repair devices.

"Technical Plan"

In order to achieve the above purpose, a micro LED display repair device of the present invention is used to repair defects of micro LED displays, including: a pedestal to accommodate a micro LED display, and the micro LED display includes a micro LED chip. and a circuit pattern for driving the micro LED chip; a laser light source that provides laser light to remove a defective portion of the micro LED display; and an optical module that changes the light source from the laser light source. generate a path of laser light and irradiate the laser light to remove a preset specific area so as to repair the defective part of the micro LED display, wherein the optical module removes the preset specific area The circuit pattern is removed to a depth to expose the lower portion of the micro LED display, wherein the circuit pattern is used to provide power required for operation of the micro LED chip.

In addition, the circuit pattern of the present invention includes a driving line and an additional auxiliary line for driving the micro LED chip, and the preset specific area to be removed by the optical module is in the The part of the micro LED display where the defective micro LED chip is located, or the part of the auxiliary line closest to the defective micro LED chip.

In addition, the present invention also includes a cleaning module for cleaning the remaining foreign matter after the optical module irradiates the defective part in the micro LED display with laser light to remove it.

In addition, the cleaning module of the present invention uses a hair dryer method to blow predetermined gas in order to clean the remaining foreign matter in the defective part.

In addition, the optical module of the present invention includes a scanner for changing the path of the laser light so as to irradiate the laser light provided from the laser light source to the defective part of the micro LED display.

In addition, the present invention also includes a mounting module for mounting a normal micro LED chip on the removed portion after the optical module removes the defective portion of the micro LED display.

In addition, the mounting module of the present invention also includes an ink module, which sprays conductive ink on the upper part of the circuit pattern so that the normal micro LED chip can be installed on the removed optical module. The circuit pattern is then exposed.

In order to achieve the above objectives, a method for repairing defects in a micro LED display of the present invention includes the following steps: moving a micro LED display including a micro LED chip and a circuit pattern for driving the micro LED chip to a A pedestal; using an optical module to change the path of laser light provided from a laser light source and irradiating the micro LED display to remove a specific area, so as to remove defective parts of the micro LED display; and converting normal micro LED displays to The LED chip is installed in the specific area removed by the optical module.

In addition, in the present invention, in the specific area to be removed, the optical module removes the specific area to be removed to a depth to expose the circuit pattern in the lower part of the micro LED display, wherein the circuit pattern It is used to provide the power required for operation to the micro LED chip.

In addition, in the present invention, in the specific area to be removed, the circuit pattern includes a driving line and an additional auxiliary line for driving the micro LED chip. The specific area to be removed by the optical module is The portion of the micro LED display where the defective micro LED chip is located, or the portion of the auxiliary line closest to the defective micro LED chip.

In addition, the present invention also includes: after removing the specific area from the optical module, a cleaning module cleans the remaining foreign matter after removing the specific area.

In addition, in the cleaning step of the present invention, the cleaning module blows a preset gas using a hair dryer method to remove remaining foreign matter in the defective part.

In addition, the normal micro LED chip installation step of the present invention also includes: an ink module sprays conductive ink on the upper part of the lower circuit pattern, so that the normal micro LED chip is installed on the optical The lower circuit pattern is exposed after the module is removed.

"Invention Effect"

The invention structured as above has the effect of repairing defects in micro-LED displays that cannot be repaired by traditional repair methods.

Additionally, after specific areas are removed to repair defective LED wafers, cleaning maximizes the repair success rate.

Additionally, a repair optimized for micro-LED displays can be performed by installing a normal LED chip via ink after removing or disabling the defective LED chip.

The micro LED display repair device and method according to the present invention are described in detail below with reference to the accompanying drawings.

FIG. 1 is a perspective view of a micro LED display repair device according to an embodiment of the present invention; FIG. 2 is a view showing the cleaning process after removing a specific area through the micro LED display repair device of the present invention; FIG. 3 is a view showing the cleaning process of the micro LED display repair device according to the present invention. The micro LED display repair device is a view of the process of making the micro LED to be repaired inoperable; Figure 4 is a view showing an example of the circuit mode of the micro LED display of the present invention; Figure 5 is a view showing the micro LED display repair device of the present invention Figure 6 is a view showing the cross-section of the micro LED display after repair of the present invention; and Figure 7 is a flow chart showing the repair method of the micro LED display of the present invention.

LCD and OLED were representative displays of flat panel displays until recently, but as mentioned above, LCD is not self-luminous and therefore requires a light source such as a backlight. Curved displays with a certain degree of curvature are possible due to backlight source limitations, but foldable displays with LCDs are not possible. OLED is self-luminous, but due to the use of organic light-emitting materials, aging and durability will deteriorate. Due to the problems with FPDs such as traditional LCDs and OLEDs, micro-LED displays that can emit light and do not suffer from aging and other problems have become the focus of attention.

The manufacturing of traditional FPD basically includes a repair process to make the bad pixels generated due to foreign matter during the FPD manufacturing process work properly. In order to solve the problem of pixels not working properly due to foreign matter during the FPD manufacturing process, the repair process mainly uses the wiring process of connecting the circuit pattern when the wire is broken due to foreign matter, and the cutting process of cutting the circuit pattern when the short circuit occurs. The micro LED display also has a substrate micro LED display with a circuit pattern at the bottom including the driving line DL and the auxiliary line AL used as a backup when the driving line DL does not work, as shown in the example shown in Figure 4. The traditional repair process can Directly suitable for circuit substrates of micro LED displays. Since micro LED displays are in the form of very small LED wafers with as many pixels as the number of mounted pixels, and their configuration is different from traditional FPDs, a different repair method is required from the traditional repair process, and the present invention is specifically used for such micro LEDs Display repair apparatus and method.

The micro LED display repair device of the present invention includes a pedestal 100, a laser light source 200 and an optical module 300. The pedestal 100 accommodates a micro LED display at the top, in order to repair a defective part of the micro LED display, the micro LED display includes a micro LED chip and a circuit pattern for driving the micro LED chip, the circuit pattern includes a driving line DL and an auxiliary line AL. In order to remove defective parts of the micro LED display, the laser light source 200 provides laser light to remove specific areas. The optical module 300 changes the path of the laser light to illuminate the laser light provided by the laser light source. As mentioned above, the micro LED display mounts the LED chip on the circuit pattern to configure the display, and after the LED chip is mounted, a protective film 20 is usually formed to protect the display. Various types of protective films 20 can be used, and the protective film 20 must naturally be made of a transparent material and must be durable to prevent damage to the mounted LED chip. As an example of the protective film 20 , anisotropic conductive film (ACF) that conducts electricity in only one direction can be used. The main reason for using anisotropic conductive film ACF is to protect the LED chip mounted on the substrate, and the other reason is that the fine conductive particles in the anisotropic conductive film ACF also have the effect of strengthening the connection between the LED chip and the substrate circuit. When a specific area of the micro LED display is removed by the optical module 300, the specific area is preferably processed to a depth where the circuit patterns of the driving lines DL, the auxiliary lines AL, etc. provided at the bottom of the protective film 20 such as ACF are exposed. . This is because when a normal LED chip is mounted on a circuit pattern, it needs to be electrically connected to the driving line DL or the auxiliary line AL. Figure 6 shows that the driving line DL and the auxiliary line AL are electrically connected, but this shows that the part where the driving line DL is located is removed and connected, and the part where the auxiliary line AL is located is removed and connected. Therefore, if the LED chip Connected to any circuit pattern, the driver can be realized. However, as mentioned above, the abnormal micro LED can be removed to expose the circuit pattern, but as shown in Figure 3, after cutting off the specific area of the abnormal micro LED and disabling the abnormal micro LED, it can also be removed by removing the normal micro LED. The micro LED is mounted in the circuit pattern provided by the auxiliary for repair. Of course, compared with the method of completely removing the abnormal micro LED and then installing the normal micro LED, this repair method cannot be called a very precise repair because the installation position of the micro LED is different from the original one. However, since the original micro LED is located There is not much gap between the part and the auxiliary circuit pattern, and the repair effect is not very different. The cleaning process is easy, and there are almost no by-products that may be produced during the removal process, so that the repair can be performed more effectively. Of course, since there are pros and cons, it is best to consider the environment in which the restoration is to be carried out.

In addition, not only when removing specific areas of the micro LED display by irradiating laser light through the laser light source 200 and the optical module 300, but also when disabling abnormal micro LEDs, the process of installing a normal micro LED chip is required. For this process, the repair device of the present invention may further include a cleaning module 400 for removing foreign matter F remaining on the circuit pattern and a mounting module 500 for mounting the normal LED chip after the cleaning is completed, which is beneficial to Complete the repair process instantly in one device.

The pedestal 100 of the present invention is used to keep the micro LED display fixed on the top to perform the repair process of the micro LED display. Preferably, the size of the pedestal 100 is configured according to the size of the micro LED display to be repaired. The detailed structure of the pedestal 100 can be configured in various ways depending on whether sound pressure is used to prevent the display from flowing during the repair process or when lighting is required at the bottom, the repair process environment can be configured such that the bottom is transparent, etc.

The laser light source 200 of the present invention is configured to provide laser light to perform the repair process. Depending on the characteristics of the micro LED display to be repaired, the laser light provided from the laser light source 200 may use CW laser light or pulse type. In addition, for the efficiency of the removal process, it is best to use a suitable wavelength band of laser light, and the output of the laser light is also consistent.

The optical module 300 of the present invention is configured to change the path of laser light provided from the laser light source 200 and irradiate the laser light to an appropriate position to repair defects. The optical module 300 is usually composed of multiple mirrors and lenses. The irradiation method can be roughly divided into a scanner method that directly irradiates the laser light provided by the laser light source 200 to the micro LED display and a method that uses an objective lens with an appropriate focal length. Using the scanner method has the advantage that the optical module 300 can be simplified and rapid path changes can be achieved since the laser light is directly irradiated. However, if an image module to be photographed for the repair process is additionally configured, the laser light irradiation process and image acquisition are performed separately, so matching the coordinate system is troublesome and it is difficult to organically control the repair process. The method of using multiple mirrors and objective lenses has the disadvantage that the configuration of the optical module 300 is complicated. However, since the laser light irradiation optical system and the image capturing optical system can be processed as one configuration, this method has the advantage of enabling laser light irradiation. The advantage is that the image is captured in the same coordinate system and the repair process can be processed organically. The repair process of micro LED displays can be done in any way, which is best determined by combining the environment and characteristics of the repair process.

The optical module 300 irradiates the defective micro LED display with laser light to remove the parts to be repaired. As mentioned above, the micro LED display is composed of a substrate with a circuit pattern on the bottom, and a protective film 20 that protects the LED chip mounted on the substrate. The optical module 300 removes the protective film 20 of the micro LED display, and removes the protective film 20 to a depth D at which the circuit pattern is exposed at the bottom, so that a normal LED chip 10 can be installed. Traditionally, the process of applying metal and sintering with laser light to cut or connect the circuit pattern is performed, but in the case of micro LED displays, the repair is performed by the process of mounting the LED wafer, and therefore, the circuit pattern is not cut or connected. process, but it is essential to remove the protective film 20 to the depth D where the circuit pattern is exposed. Of course, in the case of disabling the abnormal micro LED, the protective film does not need to be removed to a depth where the circuit pattern is exposed, and it needs to be cut to the extent that the abnormal micro LED does not work.

In addition, the optical module 300 can directly remove the portion with the defective LED chip in the micro LED display, or can remove the portion with the auxiliary line AL as the additional driving line DL. If the defective part is directly removed, the malfunctioning LED chip should be removed, so the removal process is complicated and a large amount of foreign matter may appear, but this has the advantage of not requiring a process of disabling the malfunctioning LED chip. . If the part with the auxiliary line AL is removed, a process of disabling the malfunctioning LED chip is required, but since only the protective film 20 is removed, the removal process is simple.

The optical module 300 of the present invention is a component that removes the location of the defective LED chip in the micro LED display, or removes the location of the auxiliary line AL as the additional drive line DL. The size of the removed part follows the size of the micro LED chip. Dimensions can be changed. In addition, in order to display images, the display is composed of three chips that display red-green-blue (RGB) colors. If the defective chip is one of RGB, only the chip can be removed. However, in the small size of the LED chip Or when it is composed of one wafer, although there is only one defective wafer in RGB, all RGB can be removed. The optical module 300 of the present invention can adjust the size of the removed part according to the resolution of the micro-LED display to be repaired. In order to adjust the size of the removed part in this way, the present invention can adjust the position and size of the part to be removed under the control of a controller (not shown). In particular, it is preferred that the size of the portion to be removed is greater than 5 microns and less than 100 microns. The reason is that if the part to be removed is too small, it is difficult to remove with laser light, and if the part to be removed is too large, removal will take too long. If the size of the part to be removed is less than 5 microns and greater than 100 microns, it is better to choose the repair method of darkening the defective LED chip. In addition, in order to remove the LED chip with defective locations within a preset time, the controller can control the output of the laser light source 200 to become larger, or change the wavelength used during removal. In addition, when the thickness of the LED chip to be removed is less than 30 microns, it is preferable to remove the LED chip by selecting the optical module 300 of the present invention. If the thickness of the LED chip to be removed is greater than 30 microns, as mentioned above, since the removal time becomes longer, it is better to choose not to use chemical methods or to adjust the laser light output, wavelength, etc. emitted by the laser light source 200. How to remove radioactive properties. That is, preferably, the first step is to remove the protective film protecting the LED chip, and then, the second step is to remove the LED chip. Since the protective film and the LED chip are made of different materials, the laser light characteristics need to be changed for effective removal.

The cleaning module 400 of the present invention is configured to clean the foreign matter F in the area removed by the optical module 300 . When the protective film 20 and the like are removed by laser light, foreign matter F generated during the removal process may exist in the removal area. When a normal LED chip 10 is installed, these foreign matter F may cause poor contact with the circuit pattern, so Better execution of the cleaning process.

The cleaning method of the cleaning module 400 can be a cleaning liquid method or a hair dryer method of blowing cleaning gas. In the case of using the cleaning liquid method, the cleaning effect is excellent, but the configuration for recovering the cleaning liquid must be prepared separately, and because the repair process is performed in a clean room environment, the cleaning process or post-processing may be very difficulty. In the case of the hair dryer method, the cleaning effect may be lower than that of using cleaning liquid, but the cleaning process is very simple and the configuration of the cleaning module 400 can be simplified. The cleaning gas can be selected according to the configuration of the protective film 20 of the micro LED display, but carbon dioxide is preferably used to maximize the cleaning effect.

The mounting module 500 of the present invention is configured to remove the protective film 20 in a specific area through the optical module 300 and remove the foreign matter F on the circuit pattern through the cleaning module 400, and then perform the mounting of the LED chip. As the mounting module 500 for mounting LED chips, one embodiment of the present invention uses an ink module spraying ink method, which injects conductive ink 1 such as silver (Ag) through the nozzle unit 510 into the driving line DL or auxiliary AL on line. In the case of using the ink injection method, this has the advantage that the electrical contact between the LED chip and the circuit pattern can be configured very simply, and a minute amount of ink can be accurately ejected onto the circuit pattern with a very fine width. It is best to use the EHD (Electrohydrodynamics, electrohydrodynamics) inkjet method to correctly spray tiny amounts of ink to the exact location. Of course, the mounting module 500 may not only include a configuration for inkjet, but may also include a transfer module that accurately positions the normal LED chip 10 at the inkjet position. In addition, as shown in FIG. 5 , it is of course possible to further include a configuration for applying the protective film 20 after mounting the normal LED chip 10 .

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

In the micro LED display repair method of the present invention, the micro LED display including the micro LED chip and the circuit pattern for driving the chip that needs to be repaired is moved to the pedestal 100 and then fixed by suction or the like (S100). The optical module 300 changes the path of the laser light provided from the laser light source 200 and irradiates the laser light to the defective part of the micro LED display fixed on the pedestal 100 to remove the specific area (S110). The normal LED chip is installed on the specific area removed by the optical module 300 (S120).

100:pedestal 200:Laser light source 300: Optical module 400:Cleaning module 500:Install module 510:Nozzle unit 1: Conductive ink 10:LED chip 20:Protective film DL: drive line AL: auxiliary line D: Depth F: Foreign body S100~S120: steps

Figure 1 is a perspective view of a micro LED display repair device according to an embodiment of the present invention; 2 is a view showing the cleaning process after removing a specific area by the micro LED display repair device of the present invention; 3 is a view showing the process of making the micro LED to be repaired inoperable by the micro LED display repair device of the present invention; 4 is a view showing an example of a circuit mode of the micro LED display of the present invention; Figure 5 is a view showing the installation process through the installation module of the micro LED display repair device of the present invention; Figure 6 is a view showing a cross-section of the repaired micro LED display of the present invention; and Figure 7 is a flow chart showing the micro LED display repair method of the present invention.

100:pedestal

200:Laser light source

300: Optical module

400:Cleaning module

500:Install module

Claims (6)

A repair device for a micro LED display, used to repair defects of the micro LED display, including: a base to accommodate the micro LED display, the micro LED display includes a micro LED chip and a micro LED chip for driving the micro LED display. a circuit pattern of an LED chip; a laser light source that provides laser light to remove a defective portion of the micro LED display; and an optical module that changes the path of the laser light generated from the laser light source and irradiating the laser light to remove a preset specific area to repair the defective part of the micro LED display; a cleaning module for cleaning the optical module in the micro LED display The defective part is irradiated with laser light to remove the remaining foreign matter; a mounting module is used to install the normal micro LED chip after the optical module removes the defective part of the micro LED display. Installed on the removed part, wherein the optical module includes a scanner for changing the path of the laser light to irradiate the laser light provided from the laser light source to the defect of the micro LED display part, and the optical module removes the preset specific area to a depth through the scanner to expose the circuit pattern in the lower part of the micro LED display, where the circuit pattern is used to The micro LED chip provides the power required for operation, and wherein the mounting module further includes an ink module that uses an EHD inkjet method to spray conductive ink on the upper part of the circuit pattern so as to The normal micro LED chip is mounted on the circuit pattern exposed after being removed from the optical module. The repair device of a micro LED display according to claim 1, wherein the circuit pattern includes a driving line and an additional auxiliary line for driving the micro LED chip, and is to be removed by the optical module The preset specific area is the part of the micro LED display where the defective micro LED chip is located, or the part of the auxiliary line closest to the defective micro LED chip. The repair device of a micro LED display according to claim 1, wherein the cleaning module blows a preset gas using a hair dryer method to clean the remaining foreign matter in the defective part. A method for repairing a micro LED display, including the following steps: moving a micro LED display including a micro LED chip and a circuit pattern for driving the micro LED chip to a base; using an optical module to change from a laser The path of the laser light provided by the irradiating light source and irradiating the micro LED display removes a specific area to a depth to expose the circuit pattern in the lower part of the micro LED display, wherein the circuit pattern is used to The micro LED chip provides the power required for operation in order to remove defective parts of the micro LED display; after the specific area is removed by the optical module, it is cleaned by a cleaning module after removing the specific area. The remaining foreign matter; a normal micro LED chip is installed in the specific area removed by the optical module; the step of installing the normal micro LED chip also includes: using an EHD inkjet method through an ink module Conductive ink is sprayed on the upper part of the circuit pattern so that the normal micro LED chip is mounted on the circuit pattern exposed after being removed from the optical module. The repair method of a micro LED display according to claim 4, wherein in the specific removal area, the circuit pattern includes a driving line for driving the micro LED chip and an additional auxiliary line, by The specific area of the optical module to be removed is the part of the micro LED display where the defective micro LED chip is located, or the part of the auxiliary line closest to the defective micro LED chip. The repair method of a micro LED display according to claim 4, wherein in the cleaning step, the cleaning module blows a preset gas using a hair dryer method to remove foreign matter remaining in the defective part.