JP2020008751A - Pixel repairing method - Google Patents

Abstract

To provide a pixel repairing method capable of easily and efficiently repairing conduction of a light-emitting element that does not light up because of conduction failure even if the light-emitting element for composing a pixel is minute.SOLUTION: A repairing method of a pixel 40 composed of a first light-emitting element 3 includes: a process for cutting one portion of a set of wiring patterns 24, 25 and electrically insulating the first light-emitting element and a set of terminals 26, 27; and a process for connecting a second light-emitting element 3 for composing the pixel to a set of spare electrode pads 22a, 22c, 23a, 23c that are formed separately from electrode pads 22b, 23b in a wiring board 4 and are connected to the set of wiring patterns for mounting it to the wiring board, and allowing the second light-emitting element to make continuity with the one set of terminals via the one set of wiring patterns.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for repairing a pixel, and, even if it is a fine light emitting element such as a micro LED chip, for example, can easily and efficiently repair conduction of a light emitting element constituting a non-lit pixel. The present invention relates to a pixel repair method that can be performed.

  For example, an LED display using an LED as a light emitting element displays a color image. As shown in FIGS. 4 (plan view) and FIG. 5 (partly enlarged sectional view), a fluorescent light emitting layer is provided on the LED array substrate 1. It is configured such that the arrays 2 are stacked.

  The LED array substrate 1 has a plurality of LED chips 3 arranged in a matrix mounted on a wiring substrate 4 as shown in FIG. 5, and a video signal from a driving circuit provided outside is supplied to each LED chip. 3 is supplied. The wiring board 4 is provided with wiring for individually turning on and off each LED chip 3 to turn on and off.

  Further, as shown in FIG. 5, the fluorescent light emitting layer array 2 has a plurality of fluorescent lights which are excited by the exciting light L emitted from the LED chip 3 and convert the wavelength into the fluorescent light FL of the corresponding color (R, G, B). It has a light emitting layer 11 (11R, 11G, 11B). As shown in the figure, fluorescent light-emitting layers 11 corresponding to each color of red (R), green (G), and blue (B) are provided on a transparent substrate 13 in a state of being separated by partition walls 12. Each fluorescent light emitting layer 11 is filled with fluorescent dye particles corresponding to each color.

One LED chip 3 corresponds to each fluorescent light emitting layer 11, and one fluorescent light emitting layer 11 (11R / 11G / 11B) and one LED chip 3 constitute a sub-pixel 20 (20R / 20G / 20B) of each color. ).
Further, as shown in FIGS. 4 and 5, one pixel (pixel) 40 is constituted by three sub-pixels 20 of R, G, and B.

  FIG. 6 is a plan view schematically showing the configuration of each pixel 40. As shown in FIG. 6, one LED chip 3 is arranged in an area occupied by the fluorescent light emitting layer 11 of each sub-pixel 20, and when each LED chip 3 emits light, the fluorescent light emitting layer 11 ( 11R, 11G, and 11B) are excited.

By the way, when manufacturing the LED display, it is necessary to mount the LED chip 3 on the wiring board 4 of the LED array board 1.
In the wiring substrate 4, a pair of electrode pads 5 for an anode and a cathode is provided in an area of each sub-pixel 20 (referred to as a sub-pixel region 21) as shown in FIG. The pattern 6 is drawn to the terminal 7.
On the other hand, a contact 31 corresponding to the pair of electrode pads 5 is provided on the back surface of the LED chip 3 as shown in the figure.

The electrical connection between the electrode pads 5 on the substrate side and the contacts 31 on the LED chip 3 side is made of a conductive adhesive (solder, or an adhesive of an anisotropic conductive material as disclosed in Patent Document 1). Is used.
That is, the LED chip 3 is electrically connected to the electrode pads 5 on the wiring board 4 via the conductive adhesive material, and is mounted on the board.
When the mounting of the LED chip 3 on all the sub-pixels 20 is completed, the fluorescent light emitting layer array 2 is disposed thereon, and the LED display is manufactured.

International Publication No. 2014/132977

By the way, in the LED display on which the LED chip 3 is mounted, the lighting inspection of each pixel is performed. Here, in the case where there is a pixel having a failure in lighting, color, luminance, or the like, it is necessary to perform a pixel repair process.
Specifically, in each sub-pixel, the mounted LED chip 3 having a defect is removed from the wiring board 4, mounted again without any connection failure, and re-tested.

However, in recent years, the miniaturization of light emitting elements has been advanced. For example, when a micro LED chip having an outer dimension of 10 μm × 30 μm or less is mounted as a light emitting element, the chip is fine and the pitch between the terminal pads 5 is also small. It was shorter and it was very difficult to remove the micro LED chip for repair.
That is, when manufacturing a high-definition LED display, there is a problem that the repair processing cannot be efficiently performed.

  The present invention has been made under such a problem, and even if a light emitting element forming a pixel is minute, it is possible to easily and efficiently repair the conduction of a light emitting element that has become unlit due to a conduction failure. It is an object of the present invention to provide a pixel repairing method that can be performed in a timely manner.

  In order to achieve the above object, a method for repairing a pixel according to the present invention includes a set of electrode pads to which a first light emitting element is connected, and a set of electrode pads for supplying a current to the first light emitting element. Terminal, a wiring board comprising a set of wiring patterns connecting the set of electrode pads and the set of terminals, a method of repairing a pixel configured by the first light emitting element, Cutting a part of a wiring pattern to electrically insulate the first light emitting element and the set of terminals; and forming the set of wirings formed separately from the electrode pads on the wiring board. A set of spare electrode pads connected to a pattern, a second light emitting element for constituting the pixel is connected and mounted on the wiring board, and the second light emitting element and the set of terminals are connected to each other. Conducted through the set of wiring patterns Characterized in further comprising that the step.

  A plurality of spare electrode pads are formed on the wiring board, and if there is a problem with lighting of the second light emitting element in the spare electrode pad to which the second light emitting element is connected, Cutting a part of the pattern to electrically insulate the second light emitting element and the set of terminals, and another light emitting element constituting the pixel to another set of spare electrode pads And connecting the other light-emitting element and the set of terminals to each other through the set of wiring patterns.

Further, it is preferable that the method further includes a step of performing a lighting inspection of the pixel and a step of coating an insulating protective film on the wiring substrate when there is no problem in the lighting inspection.
It is preferable that a plurality of the terminals connected to the wiring pattern are formed on the wiring board.
Further, the present invention is suitable even if the light emitting element is a micro LED.

According to such a method, a plurality of pairs of electrode pads on which a light emitting element (such as a micro LED) can be mounted and spare electrode pads are formed on the wiring board. Thus, when there is a problem that the light emitting element does not conduct and the pixel does not light, the light emitting element may be insulated and another light emitting element may be additionally mounted on the spare electrode pad.
That is, since it is not necessary to remove the light emitting element that causes the lighting failure, even if the light emitting element is a fine light emitting element such as a micro LED chip, the repair process of conduction can be easily and efficiently performed.
In addition, since the electrode pad after once removing the light emitting element for repair is not reused as in the related art, it is possible to avoid a defect caused by the electrode.
Further, instead of leaving the defective light emitting element, the wiring to which it is connected is cut, so that a short circuit defect with the remaining defective light emitting element can be prevented.

  ADVANTAGE OF THE INVENTION According to this invention, even if the light emitting element which comprises a pixel is fine, it can provide the repair method of the pixel which can easily perform the repair of the conduction | electrical_connection of the light emitting element turned off by conduction failure. .

FIG. 1 is a plan view showing a wiring pattern of a sub-pixel region on a wiring board for describing a first embodiment of a pixel repair method according to the present invention. FIGS. 2A to 2C are plan views for explaining a procedure for performing a conductive repair process using the wiring pattern of FIG. FIG. 3 is a plan view showing a wiring pattern of a sub-pixel region on a wiring board for describing a second embodiment according to the present invention. FIG. 4 is a plan view schematically showing the configuration of the LED display. FIG. 5 is a cross-sectional view schematically showing the configuration of the LED display. FIG. 6 is a plan view schematically showing a configuration of one pixel constituting a conventional LED display. FIG. 7 is a plan view showing a wiring pattern in one sub-pixel region forming one pixel in FIG.

Hereinafter, an embodiment of a pixel repair method according to the present invention will be described with reference to the drawings. In the following description, the same components as those already described with reference to FIGS. 4 to 7 are included, and corresponding members are denoted by the same reference numerals.
In the following embodiments, an example in which an LED chip is used as a light emitting element will be described.

FIG. 1 is a plan view showing a wiring pattern of a sub-pixel region on a wiring board for describing a first embodiment of a pixel repair method according to the present invention. Specifically, one sub-pixel region 21 formed on the wiring board 4 of the LED array substrate constituting the LED display is shown.
Note that the same configuration as the configuration shown in FIG. 1 is applied to all the R, G, and B sub-pixels in all the pixels constituting the display.

In the sub-pixel region 21 on the wiring substrate 4 shown in FIG. 1, a plurality of anode and cathode electrode pads 22 and 23 are provided. In the illustrated example, three electrode pads 22a, 22b, 22c for the anode and three electrode pads 23a, 23b, 23c for the cathode are formed in the sub-pixel region 21 on the substrate 4.
As shown in the figure, the electrode pads 22a and 23a, the electrode pads 22b and 23b, and the electrode pads 22c and 23c form a set, and one LED chip 3 can be attached (mounted).

  A pair of terminals 26 and 27 for supplying a current to the LED chip 3 (electrode pads 22 and 23) are formed on the wiring board 4.

  Further, on the wiring board 4, a wiring pattern 24 connected to the electrode pads 22a, 22b, 22c and drawn to the terminal 26 side, and connected to the electrode pads 23a, 23b, 23c and the terminal 27 side And the drawn wiring pattern 25 is formed. As shown in the drawing, in the present embodiment, the shape of the pair of wiring patterns 24 and 25 is such that opposing comb teeth mesh with each other, but the present invention is not limited to this form.

When mounting the LED chip 3 in the sub-pixel region 21, only one LED chip 3 that normally lights up needs to be present in the region, so that one LED chip 3 is mounted.
For example, as shown, in the sub-pixel region 21, the LED chip 3 (broken line portion) is mounted on the electrode pads 22b and 23b near the center thereof via a conductive adhesive. As a result, a current can be supplied to the LED chip 3 from the terminals 26 and 27. In this case, the other electrode pads 22a, 22c, 23a, and 23c are free terminals and are used as spare electrode pads.

Next, a method of repairing a pixel using the electrode pads and the wiring patterns in the sub-pixel region 21 configured as described above will be described.
For example, as shown in FIG. 2A, when an LED chip 3A (first light emitting element) indicated by a broken line is connected to the electrode pads 22b and 23b of the sub-pixel region 21, the LED chip 3A Power is supplied from terminals 26 and 27.

In the lighting inspection of the pixel, if the LED chip 3A is not lit, for example, as shown in FIG. 2B, the branch wiring 24b which is a part of the wiring patterns 24 and 25 connected to the LED chip 3A, 25b is cut by laser processing. For this laser processing, for example, a pulse laser such as YAG can be used.
Thereby, the electrode pads 22b and 23b and the pair of terminals 26 and 27 are electrically insulated. The LED chip 3A on the electrically insulated electrode pads 22b and 23b is left unremoved.

  Then, as shown in FIG. 2 (c), the LED chip 3B (second electrode pad) is placed on the spare electrode pads 22a, 23a (or the electrode pads 22c, 23c) on which the LED chip 3 is not mounted (it has become a vacant terminal). (Two light emitting elements). Here, even if the position of the LED chip 3B moves from the center position of the pixel 40, it is a minute difference in position and cannot be visually recognized.

  The lighting inspection of the pixels is performed again, and when the lighting of all the pixels constituting the display is confirmed to be normal, an insulating protective film (flattening film) such as urethane resin is coated on the LED array substrate 1. I do. With this insulating protective film, it is possible to prevent surplus wiring portions and electrodes from causing a short circuit.

  If the LED chips 3B are not turned on even if the LED chips 3B are additionally mounted on the electrode pads 22c and 23c, the branch wires 24a and 25a connected to the LED chips 3B are cut by laser processing. Then, the LED chip 3 (another light emitting element) may be additionally mounted on the remaining electrode pads 22c and 23c, and the lighting inspection of the pixel may be performed again.

Next, a second embodiment of the pixel repair method according to the present invention will be described with reference to FIG. FIG. 3 is a plan view showing a wiring pattern of a sub-pixel region on a wiring board for describing a second embodiment according to the present invention.
The configuration shown in FIG. 3 is such that, when the wiring pattern formed in the sub-pixel area 21 in FIGS. 1 and 2 is one block, a plurality of blocks are arranged in the sub-pixel area 21 (in the example shown in FIG. Four surrounding blocks Bk1 to Bk4). A plurality of terminals connected to the wiring pattern are also arranged (in the example shown, terminals 26A and 26B and terminals 27A and 27B).
When arranging a plurality of blocks Bk in the sub-pixel region as described above, it is preferable to arrange the blocks Bk in the vertical direction and the horizontal direction in order to multiplex the positions of the electrodes and the wirings.

According to such a configuration, it is not a problem of the conduction of the LED chip 3 itself or a problem of the conduction of the LED chip 3 and the electrode chips 22 and 23, but a repair in a case where a cause is caused by a wiring earlier than the problem. be able to. For example, when there are disconnection defects D1 and D2 as shown in FIG. 3, blocks Bk3 and Bk4 may be used.
That is, by multiplexing the arrangement location of the LED chips 3 and the spare wirings in the vertical and horizontal directions, it is possible to further improve the probability of being correctable.

As described above, according to the embodiment of the present invention, a plurality of sets of electrode pads on which the LED chip 3 can be mounted and spare electrode pads are formed in the sub-pixel region on the wiring board. Thus, when there is a problem that the LED chip 3 does not conduct and the pixel does not light, the LED chip 3 may be insulated and another LED chip 3 may be additionally mounted on the spare electrode pad.
That is, since it is not necessary to remove the LED chip 3 that causes the lighting failure, the continuity repair process can be easily and efficiently performed even if the LED chip 3 is a fine light emitting element such as a micro LED chip. .
In addition, since the electrode pad after once removing the LED chip for repair is not reused as in the related art, it is possible to avoid a defect caused by the electrode.
Further, instead of leaving the defective LED chip, the wiring to which it is connected is cut, so that a short-circuit defect with the remaining defective LED chip can be prevented.

In the first embodiment, the other electrode pads 22 and 23 except for the electrode pads 22 and 23 at the center of the sub-pixel region 21 are used as spare electrode pads. It is not limited to the example.
That is, any set of the electrode pads 22 and 23 in the sub-pixel region 21 may be mainly used instead of the spare.

  Further, in the above-described embodiment, the case where the light emitting element is an LED chip including a micro LED has been described. However, the present invention is not limited to this. It may be a part.

DESCRIPTION OF SYMBOLS 1 LED array board 2 Fluorescent light emitting layer array 3 LED chip (light emitting element)
3A LED chip (first light emitting element)
3B LED chip (second light emitting element)
Reference Signs List 4 wiring board 6 wiring pattern 11 fluorescent light emitting layer 12 partition 13 transparent substrate 20 subpixel 21 subpixel area 22a electrode pad (preliminary electrode pad)
22b electrode pad 22c electrode pad (spare electrode pad)
23a Electrode pad (spare electrode pad)
23b electrode pad 23c electrode pad (spare electrode pad)
24 wiring pattern 25 wiring pattern 26 terminal 27 terminal 31 contact 40 pixel

Claims (5)

A set of electrode pads to which a first light emitting element is connected, a set of terminals for supplying current to the first light emitting element, and a connection between the set of electrode pads and the set of terminals A set of wiring patterns, and a wiring board comprising: a method for repairing a pixel configured by the first light emitting element,
Cutting a part of the wiring pattern, and electrically insulating the first light emitting element and the set of terminals;
A second light emitting element for forming the pixel is connected to a set of spare electrode pads formed separately from the electrode pads on the wiring substrate and connected to the set of wiring patterns, and the wiring is formed. Mounted on a substrate, a step of conducting the second light emitting element and the set of terminals through the set of wiring patterns,
A method for repairing pixels. A plurality of spare electrode pads are formed on the wiring board, and in the spare electrode pad to which the second light emitting element is connected, when there is a problem in lighting of the second light emitting element,
Cutting a part of the wiring pattern, and electrically insulating the second light emitting element and the set of terminals;
Another light emitting element constituting the pixel is connected to another set of spare electrode pads and mounted on the wiring board, and the other light emitting element and the set of terminals are connected through the set of wiring patterns. A step of conducting,
The pixel repair method according to claim 1, further comprising: Further performing a lighting inspection of the pixel;
When there is no problem in lighting inspection, a step of coating an insulating protective film on the wiring board,
The pixel repair method according to claim 1 or 2, further comprising:   4. The method according to claim 1, wherein a plurality of the terminals connected to the wiring pattern are formed on the wiring board. 5.   The method according to claim 1, wherein the light emitting element is a micro LED.

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