WO2021149234A1

WO2021149234A1 - Led display panel and method for producing led display panel

Info

Publication number: WO2021149234A1
Application number: PCT/JP2020/002437
Authority: WO
Inventors: 中野　勇三
Original assignee: 三菱電機株式会社
Priority date: 2020-01-24
Filing date: 2020-01-24
Publication date: 2021-07-29
Also published as: JPWO2021149234A1; JP6735957B1

Abstract

The purpose of the present invention is to provide an LED display panel in which LED elements are easily detachable from components or from members disposed around the LED elements. The LED display panel includes a substrate (1), a plurality of LED elements (2), a gap filling layer (3), an adhesion reducing layer, and a surface protecting substrate (4). The plurality of LED elements (2) are discretely mounted in a matrix on the substrate (1). The gap filling layer (3) is provided between the plurality of LED elements (2). The surface protecting substrate (4) has light transmittance and covers the gap filling layer (3) and the plurality of LED elements (2). The surface protecting substrate (4) includes an adhesive layer (41) which is in contact with the gap filling layer (3) and the plurality of LED elements (2). The adhesive strength of the adhesive layer (41) is greater than the adhesive strength between the gap filling layer (3) and the plurality of LED elements (2) and is greater than the adhesive strength between the gap filling layer (3) and the substrate (1).

Description

LED display panel and manufacturing method of LED display panel

This disclosure relates to an LED display panel and a method for manufacturing the LED display panel.

The LED display panel constituting the LED (Light Emitting Diode) display device includes a plurality of LED elements arranged in a square manner, and displays video information by blinking control for each LED element.

LED display devices have come to be widely used for outdoor and indoor advertisement display, etc. due to technological development and cost reduction of LED elements. Conventionally, LED display devices have been mainly used for displaying moving images such as natural images and graphics. However, in recent years, the viewing distance has become shorter due to the narrowing of the pixel pitch, and LED display devices have also been used for displaying still images in conference rooms and surveillance systems. For example, LED display devices in surveillance applications often display personal computer images that are close to still images.

The mainstream LED element part used in the LED display device is an SMD (Surface Mount Device) type LED element. The SMD type LED element is packaged and contains an LED and a resin for sealing the LED. In the SMD type LED element, the LED is mounted in a cavity molded of ceramic or resin, and is sealed with resin from above. Conventionally, such SMD type LED elements are widely used in large display devices having a pixel pitch of 3 mm or more.

In recent years, with the cost reduction and miniaturization of LED elements, higher definition SMD type LED display devices have been put on the market. For example, a display device having a pixel pitch of 2.5 mm, 1.9 mm, 1.5 mm, 1.2 mm, or the like has been realized. In order to further improve the definition, a 4in1 type SMD type LED element in which LEDs constituting 4 pixels are sealed in one package has been put into practical use. Further, a COB (Chip On Board) type LED element in which the LED itself is directly mounted on the substrate is also adopted. As described above, there are many cases of LED display devices having a pixel pitch of 1 mm or less, in which a mini LED element or a micro LED element is adopted to increase the density.

Patent Document 1 discloses a dot matrix light emitting display (LED display device). The dot-matrix light emitting display body includes a large number of LED elements arranged vertically and horizontally, and a mask plate having a mortar-shaped through hole whose inner surface functions as a light reflecting surface formed around each LED element. The inside of the through hole is sealed with a translucent resin, and a surface condensing plate is arranged above the LED element and the mortar-shaped hole. The surface condensing plate is provided with a through hole corresponding to the position of the LED element, and a convex lens is provided at the upper opening of the through hole. This dot matrix light emitting display realizes desired orientation characteristics, enhances light utilization efficiency, and improves contrast.

Further, Patent Document 2 discloses a light emitting device (LED display device). The light emitting device includes a plurality of LED elements arranged two-dimensionally on a substrate, and a reflection case provided with a plurality of holes corresponding to the plurality of LED elements. An alignment mark is provided on the reflective case, and the positions of the substrate provided with the LED element and the reflective case provided with the holes can be aligned with high accuracy. This light emitting device improves the orientation characteristics and reduces the uneven brightness.

Further, Patent Document 3 discloses a technique for increasing the contrast of a display panel (LED display device). In the display panel, an LED element substrate in which a plurality of LED elements are arranged two-dimensionally and a transparent substrate in which a black matrix is formed are arranged so as to face each other. On the transparent substrate, an opening is arranged at a position where it overlaps with each LED element in a plane. The distance between the LED element substrate and the transparent substrate is defined by a spacer. The interval is sealed with a sealing resin. Since the distance between the LED element substrate and the transparent substrate is shortened, the contrast of the display panel is improved.

Jikkenhei No. 5-52882 Japanese Unexamined Patent Publication No. 2004-79750 Japanese Unexamined Patent Publication No. 2015-184542

Of the plurality of LED elements constituting the LED display device, in order to replace or repair the LED element in which a problem such as non-lighting has occurred, it is necessary to separate the LED element and its surrounding parts or members. .. However, since the LED element is adhered to the surrounding parts and members, it cannot be easily separated.

The present disclosure has been made to solve the above problems, and an object of the present disclosure is to provide an LED display panel in which the LED element portion and its surrounding parts or members can be easily separated.

The LED display panel according to the present disclosure includes a substrate, a plurality of LED element portions, a gap filling layer, an adhesion reducing layer, and a surface protection substrate. The plurality of LED element units are mounted on the substrate in a discrete and matrix manner. The gap filling layer is provided between the plurality of LED element portions. The surface protection substrate has light transmission and covers the gap filling layer and the plurality of LED element portions. The surface protection substrate includes a gap filling layer and an adhesive layer in contact with a plurality of LED element portions. The adhesive force of the adhesive layer is larger than the adhesive force between the gap filling layer and the plurality of LED element portions and the adhesive force between the gap filling layer and the substrate.

According to the present disclosure, it is possible to provide an LED display panel in which the LED element portion and its surrounding parts or members can be easily separated.

The purposes, features, aspects, and advantages of this disclosure will be made clearer by the following detailed description and accompanying drawings.

It is a top view which shows the structure of the LED display device in Embodiment 1. FIG. It is sectional drawing which shows the structure of the LED display panel in Embodiment 1. FIG. It is a partial cross-sectional view which shows the detailed structure of the region C shown in FIG. It is a flowchart which shows the manufacturing method of the LED display panel in Embodiment 1. It is a figure which shows the outline of the manufacturing method of the LED display panel in Embodiment 1. FIG. It is a figure which shows the outline of the manufacturing method of the LED display panel in Embodiment 1. FIG. It is a figure which shows the outline of the manufacturing method of the LED display panel in Embodiment 1. FIG. It is a figure which shows the outline of the manufacturing method of the LED display panel in Embodiment 1. FIG. It is a figure which shows the outline of the manufacturing method of the LED display panel in Embodiment 1. FIG. It is a flowchart which shows the manufacturing method by repairing the LED display panel in Embodiment 1. It is a figure which shows the outline of the manufacturing method by repairing the LED display panel in Embodiment 1. FIG. It is a figure which shows the outline of the manufacturing method by repairing the LED display panel in Embodiment 1. FIG. It is a figure which shows the outline of the manufacturing method by repairing the LED display panel in Embodiment 1. FIG. It is a figure which shows the outline of the manufacturing method by repairing the LED display panel in Embodiment 1. FIG. It is a figure which shows an example of the light distribution characteristic in one LED display panel. It is a figure which shows an example of the light distribution characteristic in the LED display device which includes a plurality of LED display panels. It is sectional drawing which shows the structure of the LED display panel in Embodiment 2. FIG. It is a flowchart which shows the manufacturing method of the LED display panel in Embodiment 2. It is a figure which shows the outline of the manufacturing method of the LED display panel in Embodiment 2. It is a figure which shows the outline of the manufacturing method of the LED display panel in Embodiment 2. It is a figure which shows the outline of the manufacturing method of the LED display panel in Embodiment 2. It is a figure which shows the outline of the manufacturing method of the LED display panel in Embodiment 2. It is a figure which shows the outline of the manufacturing method of the LED display panel in Embodiment 2. It is a figure which shows the outline of the manufacturing method of the LED display panel in Embodiment 2. It is a flowchart which shows the manufacturing method by repairing the LED display panel in Embodiment 2. It is a figure which shows the outline of the manufacturing method by repairing the LED display panel in Embodiment 2. It is a figure which shows the outline of the manufacturing method by repairing the LED display panel in Embodiment 2. It is a figure which shows the outline of the manufacturing method by repairing the LED display panel in Embodiment 2. It is a figure which shows the outline of the manufacturing method by repairing the LED display panel in Embodiment 2. It is a figure which shows the outline of the manufacturing method by repairing the LED display panel in Embodiment 2. It is a figure which shows another example of the manufacturing method by repairing the LED display panel in Embodiment 2. FIG. It is sectional drawing which shows the structure of the LED display panel in Embodiment 3. FIG. It is sectional drawing which shows the structure of the LED display panel in the modification of Embodiment 3.

<Embodiment 1>
(Constitution)
FIG. 1 is a plan view showing the configuration of the LED (Light Emitting Diode) display device 100 according to the first embodiment. The LED display device 100 includes a plurality of LED display panels 10 arranged in a matrix, and the plurality of LED display panels 10 constitute one large screen. Further, the LED display panel 10 includes a plurality of LED element units 2, and the plurality of LED element units 2 are arranged in a matrix.

FIG. 2 is a cross-sectional view showing the configuration of the LED display panel 10 according to the first embodiment. FIG. 2 shows a cross section of the line segment AB shown in FIG. FIG. 3 is a partial cross-sectional view showing a detailed configuration of the region C shown in FIG.

The LED display panel 10 includes a substrate 1, a plurality of LED element portions 2, an adhesion reducing layer (not shown), an ultraviolet blocking layer (not shown), and a gap filling layer 3.

The substrate 1 is, for example, an epoxy substrate containing glass fiber.

The plurality of LED element units 2 are arranged discretely and in a matrix on the substrate 1. Each of the plurality of LED element units 2 includes a packaged rectangular chip component, and is, for example, a surface mount (SMD: Surface Mount Device) type LED element. The LED element unit 2 has a light emitting surface, and is mounted so that the surface opposite to the light emitting surface faces the substrate 1.

As shown in FIG. 3, the LED element unit 2 is composed of a three-color LED composed of a red LED 2R, a green LED 2G, and a blue LED 2B, and a sealing resin 2A for sealing the three color LEDs. Each of the three-color LEDs is arranged so as to emit light in the direction opposite to that of the substrate 1. The three-color LEDs are arranged side by side to form one pixel unit. The sealing resin 2A has light transmission and covers the three-color LED. The sealing resin 2A is, for example, a thermosetting resin. The thermosetting resin includes, for example, an epoxy resin and the like.

The ultraviolet blocking layer is formed on the surface of the substrate 1 on which the LED element portion 2 is mounted. The UV blocking layer is formed of, for example, an acrylic resin containing titanium oxide dispersed at the nano level.

The adhesive reduction layer is formed between the LED element portion 2 and the gap filling layer 3 and between the substrate 1 exposed from between the plurality of LED element portions 2 and the gap filling layer 3. Here, the adhesion reducing layer is formed on the ultraviolet blocking layer. The adhesive reduction layer is formed by a so-called light release coat or a resin adhesion inhibitor. The adhesive reduction layer contains, for example, a fluorine compound, a silicon compound, a silicon fluoride compound, and the like. The adhesive reduction layer reduces the adhesiveness of the gap filling layer 3. Specifically, the adhesive reduction layer weakens the adhesiveness between the LED element portion 2 and the gap filling layer 3 and the adhesiveness between the substrate 1 and the gap filling layer 3.

The gap filling layer 3 is provided between the plurality of LED element portions 2. In the LED element portion 2 arranged on the outermost periphery of the LED display panel 10, a gap filling layer 3 is also provided around the LED element portion 2. The gap filling layer 3 in the first embodiment is black. Although the details will be described later, since the gap filling layer 3 is black, the gap filling layer 3 realizes the same function as the black matrix. Further, the gap filling layer 3 has a function of protecting the LED element portion 2.

The gap filling layer 3 has a property that the volume expands more than the plurality of LED element portions 2 by heating from the outside. For example, when the LED display panel 10 is heated, the gap filling layer 3 expands more than the LED element portion 2. As the gap filling layer 3 expands due to heating, the gap filling layer 3 is easily peeled off from the substrate 1 and the LED element portion 2. In particular, when the adhesive reduction layer is formed, the gap filling layer 3 is easily peeled off.

The gap filling layer 3 contains the gap filling material 30 and the heat-expandable fine particles 31 mixed in the gap filling material 30. The gap filler 30 is preferably an elastic resin or a resin that is softened by heating. Alternatively, the gap filler 30 is preferably a slightly adhesive resin. The gap filler 30 is, for example, a resin containing urethane acrylate.

The heat-expandable fine particles 31 have a larger coefficient of thermal expansion than the gap filler 30. For example, when the gap-filled layer 3 containing no heat-expandable fine particles 31 and the gap-filled layer 3 containing the heat-expandable fine particles 31 are heated at the same temperature, the gap-filled layer 3 containing the heat-expandable fine particles 31 , The volume expands more than the gap filling layer 3 that does not contain the thermally expandable fine particles 31. The volume expansion coefficient of the heat-expandable fine particles 31 is preferably 50 times or more the volume expansion coefficient of the gap filler 30. The degree of expansion of the gap filling layer 3 due to heating is adjusted by, for example, the volume expansion rate or the mixing amount of the heat-expandable fine particles 31. The heat-expandable fine particles 31 are, for example, a heat-expandable capsule 31A. The heat-expandable capsule 31A has a shell structure containing a low boiling point hydrocarbon. The outer shell of the shell structure is made of a polymer material, and is, for example, a resin containing acrylic. In the gap filling layer 3 of the first embodiment, the heat-expandable capsule 31A as the heat-expandable fine particles 31 is kneaded with the resin containing urethane acrylate as the gap-filling material 30.

(Production method)
FIG. 4 is a flowchart showing a method of manufacturing the LED display panel 10 according to the first embodiment. 5 to 9 are diagrams showing an outline of a method for manufacturing the LED display panel 10 according to the first embodiment.

In step S11, the substrate 1 on which the LED element portion 2 is surface-mounted is prepared. The surfaces of the substrate 1 and the LED element portion 2 are lightly peeled and coated. That is, an adhesive reduction layer containing a fluorine compound or the like is formed on their surfaces. The substrate 1 is mounted on the mold 9 so that the light emitting surface of the LED element portion 2 faces upward (FIG. 5).

In step S12, the gap filler 30 containing the heat-expandable fine particles 31 is poured between and around the LED element 2 (FIG. 6). Here, the heat-expandable fine particles 31 are heat-expandable capsules 31A, and the gap filler 30 is a gel-like resin. The heat-expandable capsule 31A is kneaded into the gel-like resin. The gel-like resin is a slightly adhesive resin and contains urethane acrylate. Further, the gel-like resin has a property of being cured by ultraviolet rays and moisture.

In step S13, the gel-like resin, that is, the gap filling material 30, is poured to the height of the light emitting surface of the LED element portion 2 (FIG. 7).

In step S14, with the substrate 1 mounted on the mold 9, ultraviolet rays are irradiated from the surface side of the substrate 1. The ultraviolet rays change the gel-like resin into a semi-cured state. After that, the semi-cured resin changes to a completely cured state by absorbing moisture (humidity) in the environment. Here, complete curing means that the fluidity of the resin after the treatment is lower than the fluidity of the gel-like resin before the treatment. The gel-like resin is cured by ultraviolet rays and changes into an elastic resin. As a result, an elastic gap filling layer 3 is formed between and around the LED element portions 2 (FIG. 8). In other words, the outer peripheral protection structure of the LED element portion 2 is formed.

In step S15, the substrate 1 is removed from the mold 9 (FIG. 9).

The LED display panel 10 is completed by the above manufacturing process. After that, a plurality of LED display panels 10 manufactured in the same process are connected in a matrix to complete the LED display device 100 having one large screen.

(Repair method)
FIG. 10 is a flowchart showing a manufacturing method by repairing the LED display panel 10 according to the first embodiment. 11 to 14 are diagrams showing an outline of a manufacturing method by repairing the LED display panel 10 according to the first embodiment.

In step S21, the LED display panel 10 is prepared. Here, the LED display panel 10 manufactured by the manufacturing method shown in FIG. 4 is prepared (FIG. 11).

In step S22, the LED display panel 10 is heated from the surface side thereof. The LED display panel 10 is heated by, for example, the radiant heat of a heater or the hot air of a dryer. The heating temperature is preferably equal to or lower than the temperature at which the gas inside the heat-expandable capsule 31A starts to leak due to excessive expansion. By this heating, the volume of the heat-expandable capsule 31A expands. Further, the volume of the resin which is the gap filling material 30 increases as the heat-expandable capsule 31A expands. That is, the gap filling layer 3 expands (FIG. 12).

In step S23, the gap filling layer 3 whose volume has expanded is peeled off from the substrate 1 and the LED element portion 2 (FIG. 13).

In step S24, the individual LED element portions 2 are exposed (FIG. 14). A part of the substrate 1 exposed by peeling the gap filling layer 3 or at least a part of the LED element parts 2 of the plurality of LED element parts 2 is repaired. Here, repair includes replacement or repair. For example, among the plurality of LED element portions 2, the defective LED element portion is replaced with a normal LED element portion. Or, instead of replacement, the defective part is repaired.

After the defective part is repaired, the LED display panel 10 is manufactured again through the process shown in FIG.

The above-mentioned gap filler 30 is a resin containing urethane acrylate and cured by ultraviolet rays and moisture, but is not limited thereto. The gap filler 30 may be an ultraviolet curable resin containing epoxy, acrylic or urethane acrylate.

(effect)
Summarizing the above, the LED display panel 10 according to the first embodiment includes a substrate 1, a plurality of LED element portions 2, and a gap filling layer 3. The plurality of LED element units 2 are mounted on the substrate 1 in a discrete and matrix manner. The gap filling layer 3 is provided between the plurality of LED element portions 2. The volume of the gap filling layer 3 expands more than that of the plurality of LED element portions 2 due to external heating. The gap filling layer 3 contains the gap filling material 30 and the heat-expandable fine particles 31 mixed in the gap filling material 30. The heat-expandable fine particles 31 have a larger coefficient of thermal expansion than the gap filler 30.

With such a configuration, when the LED display panel 10 is heated, the gap filling layer 3 expands and becomes easily peelable. That is, the LED display panel 10 in which the LED element portion 2 and the surrounding parts or members can be easily separated is realized. Conventionally, when a defect occurs in the LED element portion, it is necessary to replace or repair the LED display panel including not only the defective LED element portion but also the normal LED element portion. On the other hand, in the LED display panel 10 according to the first embodiment, as a result of the gap filling layer 3 being peeled off, the individual LED element portions 2 are exposed and can be replaced or repaired. The LED display panel 10 makes it possible to replace or repair only the defective LED element unit 2. Even when the entire LED display panel 10 is replaced, the normal LED element unit 2 and the like included in the LED display panel 10 are used, for example, as parts for repair service. The LED display panel 10 according to the first embodiment is excellent in recyclability. Further, since the LED element portion 2 and the surrounding parts or members can be easily separated, the repair work time is shortened and the repair cost is reduced.

Further, since the adhesive reduction layer is provided, the gap filling layer 3 is easily peeled off. That is, the LED display panel 10 in which the LED element portion 2 and the surrounding parts or members can be easily separated is realized. Further, when the gap filling layer 3 contains a resin slightly adhesive to the plurality of LED element portions 2 and the substrate 1, the gap filling layer 3 is more easily peeled off.

In the method of manufacturing the LED display panel 10 according to the first embodiment, the above-mentioned LED display panel 10 is prepared, the LED display panel 10 is heated from the outside, the gap filling layer 3 is expanded, and the gap filling layer whose volume is expanded is expanded. 3 is peeled off from the substrate 1 and the plurality of LED element portions 2, and at least a part of the LED element portions 2 exposed by the peeling of the gap filling layer 3 is repaired. ..

Such a manufacturing method of the LED display panel 10 makes it possible to replace or repair only the LED element portion 2 in which a defect has occurred. Further, even when the LED display panel 10 is replaced, the normal LED element unit 2 and the like included in the LED display panel 10 are used as, for example, parts for repair service. As described above, the method for manufacturing the LED display panel 10 in the first embodiment makes it possible to manufacture the LED display panel 10 having excellent recyclability.

Further, the gap filling layer 3 of the LED display panel 10 in the first embodiment is black.

With such a configuration, the orientation characteristics of each pixel are made uniform, and the visibility and contrast under external light are improved. This effect will be described below.

FIG. 15 is a diagram showing an example of light distribution characteristics in one LED display panel 10. FIG. 16 is a diagram showing an example of light distribution characteristics in the LED display device 100 including a plurality of LED display panels 10. The side surfaces of the individual LED element portions 2 constituting the

pixel units

2C and 2E are equally shielded by the black gap filling layer 3. Therefore, the light distribution characteristics of the emitted light L30 of the pixel unit 2E arranged at the left and right ends of FIG. 15, that is, the outermost periphery of the LED display panel 10, are the light distribution of the emitted light L40 of the pixel unit 2C arranged inside the pixel unit 2E. Similar to properties.

Therefore, it is possible to prevent the user from visually recognizing a difference in brightness at the boundary portion of the LED display panels 10 adjacent to each other (in FIG. 16, the boundary portion of the two pixel units 2E from which the emitted light L30 is emitted). The LED display device 100 provides a large screen with a more integrated feeling by making it difficult for the user to visually recognize the seams of the LED display panel 10.

Further, in an LED display panel having advanced high definition and high density, it is difficult to precisely align and join a substrate on which an LED element portion is mounted and a transparent substrate on which a black matrix is printed. Further, it is also difficult to mold a fine black matrix member that fits between the LED element portions, and to fit them in a precise alignment. On the other hand, in the LED display device 100 according to the first embodiment, the black matrix function is realized only by pouring a black gel-like resin between the LED element portions 2 as the gap filling material 30.

<Embodiment 2>
The LED display panel and the method for manufacturing the LED display panel according to the second embodiment will be described. The same configuration and operation as in the first embodiment will not be described.

FIG. 17 is a cross-sectional view showing the configuration of the LED display panel 11 according to the second embodiment.

The LED display panel 11 according to the second embodiment further includes the surface protection substrate 4 in the LED display panel 10 shown as the first embodiment.

The surface protection substrate 4 has light transmission and thermal conductivity. The surface protection substrate 4 is provided so as to cover the gap filling layer 3 and the light emitting surface of the LED element portion 2. The surface protection substrate 4 in the second embodiment includes a thin transparent glass substrate 40 as a substrate main body, an optical adhesive film 41 as an adhesive layer, and a surface treatment layer (not shown). The thickness of the thin transparent glass substrate 40 is, for example, 0.3 mm or less.

The optical adhesive film 41 is attached to the back surface of the thin transparent glass substrate 40. The optical adhesive film 41 is in contact with the gap filling layer 3 and the plurality of LED element portions 2. The adhesive force of the optical adhesive film 41 is the adhesive force between the gap filling layer 3 and the plurality of LED element portions 2 via the adhesive reducing layer, and the adhesive force between the gap filling layer 3 and the substrate 1 via the adhesive reducing layer. Greater than. Further, the gap filling layer 3 in the second embodiment contains an elastic resin having a slight adhesiveness to the plurality of LED element portions 2 and the substrate 1. The optical adhesive film 41 is, for example, an ultraviolet curable film. The optical adhesive film 41 is made of a resin containing, for example, epoxy, acrylic or urethane acrylate. These optical adhesive films 41 have good thermal conductivity and do not interfere with the heat dissipation of the LED element portion 2. The thickness of the optical adhesive film 41 is, for example, 0.25 mm or less.

The surface treatment layer is formed on the surface of the thin transparent glass substrate 40. The surface treatment layer is formed by a reflection reduction treatment, an antistatic treatment, a hard coat treatment, or the like. For example, a non-reflective coating, a diffusion film, or the like is formed as a surface treatment layer by the reflection reduction treatment.

(Production method)
FIG. 18 is a flowchart showing a manufacturing method of the LED display panel 11 according to the second embodiment. 19 to 24 are diagrams showing an outline of the manufacturing method of the LED display panel 11 according to the second embodiment.

In step S31, the substrate 1 on which the LED element portion 2 is surface-mounted is prepared. The surfaces of the substrate 1 and the LED element portion 2 are lightly peeled and coated. That is, an adhesive reduction layer containing a fluorine compound or the like is formed on their surfaces. The substrate 1 is mounted on the mold 9 so that the light emitting surface of the LED element portion 2 faces upward (FIG. 19).

In step S32, the gap filler 30 containing the heat-expandable fine particles 31 is poured between and around the LED element 2 (FIG. 20). Here, as in the first embodiment, the gel-like resin in which the heat-expandable capsule 31A is kneaded is poured. The resin on the gel is a slightly adhesive resin and contains urethane acrylate. Further, the gel-like resin has a property of being cured by ultraviolet rays and moisture.

In step S33, the gel-like resin, that is, the gap filling material 30, is poured to the height of the light emitting surface of the LED element portion 2. After that, with the substrate 1 mounted on the mold 9, ultraviolet rays are irradiated from the surface side of the substrate 1 (FIG. 21). The ultraviolet rays change the gel-like resin into a semi-cured state.

In step S34, the surface protection substrate 4 is covered so that the optical adhesive film 41 faces the light emitting surface of the LED element portion 2 and the gap filling layer 3 (FIG. 22).

In step S35, ultraviolet rays are irradiated from the surface side of the surface protection substrate 4. The ultraviolet rays cause the optical adhesive film 41 to be adhered and fixed to the LED element portion 2 and the gap filling layer 3. In this way, the surface protection structure of the LED element portion 2 is formed (FIG. 23).

In step S36, the substrate 1 is removed from the mold 9 (FIG. 24).

The LED display panel 11 is completed by the above manufacturing process. After that, a plurality of LED display panels 11 manufactured by the same process are connected in a matrix to complete the LED display device 100 having one large screen.

In the above manufacturing method, an ultraviolet curable optical adhesive film 41 was used as the adhesive layer of the surface protection substrate 4. However, the structure of the adhesive layer is not limited to that, and may be, for example, a structure in which a liquid resin is cured by ultraviolet rays. In that case, in step S34, the liquid ultraviolet curable resin is directly poured onto the surface of the substrate 1 in the mold 9. After that, the thin transparent glass substrate 40 is put on the resin. In step S35, ultraviolet rays are irradiated from the surface side of the thin transparent glass substrate 40. The liquid resin is cured by the ultraviolet rays, so that the surface protection substrate 4 is adhered and fixed to the LED element portion 2 and the gap filling layer 3.

(Repair method)
FIG. 25 is a flowchart showing a manufacturing method by repairing the LED display panel 11 in the second embodiment. 26 to 29 are diagrams showing an outline of a manufacturing method by repairing the LED display panel 11 in the second embodiment.

In step S41, the LED display panel 11 is prepared. Here, the LED display panel 11 manufactured by the manufacturing method shown in FIG. 18 is prepared (FIG. 26).

In step S42, the LED display panel 11 is heated from the surface side thereof. The LED display panel 11 is heated by, for example, the radiant heat of a heater or the hot air of a dryer. By this heating, the volume of the heat-expandable capsule 31A expands, and eventually the gap filling layer 3 expands. As a result, the surface protection substrate 4 floats up from the LED element portion 2 (FIG. 27).

In step S43, the surface protection substrate 4 lifted from the LED element portion 2 is peeled off from the gap filling layer 3 (FIG. 28).

In step S44, the gap filling layer 3 whose volume has expanded is peeled off from the substrate 1 and the LED element portion 2 (FIG. 29).

In step S45, the individual LED element portions 2 are exposed (FIG. 30). A part of the substrate 1 exposed by peeling the gap filling layer 3 or at least a part of the LED element parts 2 of the plurality of LED element parts 2 is repaired. For example, among the plurality of LED element portions 2, the defective LED element portion is replaced with a normal LED element portion. Alternatively, instead of replacement, the defective part may be repaired.

After the defective part is repaired, the LED display panel 11 is manufactured again through the process shown in FIG.

FIG. 31 is a diagram showing another example of the manufacturing method by repairing the LED display panel 11 in the second embodiment. As described above, the adhesive force of the optical adhesive film 41 is larger than the adhesive force between the gap filling layer 3 and the plurality of LED element portions 2 and the adhesive force between the gap filling layer 3 and the substrate 1. Therefore, in the above steps S43 and S44, the surface protection substrate 4 and the gap filling layer 3 can be peeled together from the substrate 1 and the LED element portion 2.

(effect)
Summarizing the above, the LED display panel 11 according to the second embodiment includes a substrate 1, a plurality of LED element portions 2, a gap filling layer 3, and a surface protection substrate 4. The plurality of LED element units 2 are mounted on the substrate 1 in a discrete and matrix manner. The gap filling layer 3 is provided between the plurality of LED element portions 2. The adhesion reducing layer is formed between the plurality of LED element portions 2 and the gap filling layer 3, and between the substrate 1 exposed from between the plurality of LED element portions 2 and the gap filling layer 3. The surface protection substrate 4 includes a gap filling layer 3 and an adhesive layer (optical adhesive film 41) in contact with a plurality of LED element portions 2. The adhesive force of the optical adhesive film 41 is larger than the adhesive force between the gap filling layer 3 and the plurality of LED element portions 2 and the adhesive force between the gap filling layer 3 and the substrate 1.

With such a configuration, the surface protection substrate 4 and the gap filling layer 3 can be peeled together from the substrate 1 and the LED element portion 2, so that the manufacturing process by repair becomes easy.

The LED display panel 11 in the second embodiment includes the surface protection substrate 4. For example, when assembling the LED display device 100 in which a plurality of LED display panels 11 are arranged vertically and horizontally, the surface protection substrate 4 has an LED element portion 2 arranged on the outermost periphery of the LED display panel 11 adjacent to the LED. It prevents the element portion 2 from colliding with the element portion 2 and being damaged.

Further, the surface protection substrate 4 in the second embodiment includes a substrate main body (thin plate transparent glass substrate 40) and an adhesive layer (optical adhesive film 41). The adhesive layer is more easily deformed than the substrate body. Therefore, the following effects are obtained in the manufacturing method of the LED display panel 11.

For example, in step S42, the surface protection substrate 4 is heated in order from one end to the other end. The volume expands in order from the heat-expandable capsule 31A on the end side of the substrate 1 according to the heating location. In step S43, the surface protection substrate 4 is gradually peeled off from the raised end side of the surface protection substrate 4. The difference is that the easily deformable optical adhesive film 41 is attached to the back surface of the thin transparent glass substrate 40, so that the surface protection substrate 4 can be peeled off while being curved. As a result, the peeling step of step S43 can be easily executed.

Further, the LED display panel 11 in the second embodiment includes an adhesive reduction layer. The adhesive reduction layer is formed between the plurality of LED element portions 2 and the gap filling layer 3 and between the substrate 1 exposed from between the plurality of LED element portions 2 and the gap filling layer 3, and is formed between the gap filling layers. Reduce the stickiness of 3. Further, the gap filling layer 3 in the second embodiment contains a resin that is slightly adhesive to the plurality of LED element portions 2 and the substrate 1.

With such a configuration, the gap filling layer 3 is more easily peeled off.

Further, the gap filling layer 3 in the second embodiment includes the gap filling material 30 and the heat-expandable fine particles 31 mixed in the gap filling material 30. The heat-expandable fine particles 31 have a larger coefficient of thermal expansion than the gap filler 30.

With such a configuration, when the LED display panel 11 is heated, the gap filling layer 3 expands and becomes easily peelable.

The gap filler 30 in the second embodiment is an elastic resin. The heat-expandable fine particles 31 include an outer shell and a heat-expandable capsule 31A in which the inside of the outer shell is filled with gas.

With such a configuration, a gap filling layer 3 that easily expands by heating is formed. Further, the degree of expansion of the gap filling layer 3 is adjusted by the characteristics and amount of the heat-expandable capsule 31A mixed in the gap filling material 30.

<Embodiment 3>
The LED display panel and the method for manufacturing the LED display panel according to the third embodiment will be described. The third embodiment is a subordinate concept of the first and second embodiments, and the LED display panel in the third embodiment includes each configuration of the LED display panel 11 in the second embodiment. The description of the configuration and operation similar to those of the first or second embodiment will be omitted.

FIG. 32 is a cross-sectional view showing the configuration of the LED display panel 12 according to the third embodiment.

The gap filling layer 3 in the third embodiment includes the high concentration gap filling layer 3A in contact with the surface protection substrate 4. The weight distribution ratio of the heat-expandable capsule 31A contained in the high-concentration gap-filled layer 3A is higher than the weight distribution ratio of the heat-expandable capsule 31A contained in the region closer to the substrate 1 than the high-concentration gap-filled layer 3A.

When repairing the LED display panel 12, the volume of the high-concentration gap filling layer 3A expands more than the other regions due to the radiation of the heater or the heating by the hot air of the dryer. Therefore, the surface protection substrate 4 can be easily peeled off from the LED element portion 2 and the gap filling layer 3.

(Modified Example of Embodiment 3)
FIG. 33 is a cross-sectional view showing the configuration of the LED display panel 12A in the modified example of the third embodiment.

The gap filling layer 3 includes a high-concentration gap filling layer 3B in contact with the substrate 1. The weight distribution ratio of the heat-expandable capsule 31A contained in the high-concentration gap-filled layer 3B is higher than the weight distribution ratio of the heat-expandable capsule 31A contained in the region closer to the surface protection substrate 4 than the high-concentration gap-filled layer 3B. ..

When repairing the LED display panel 12A, the volume of the high-concentration gap filling layer 3B expands more due to the radiation of the heater or the heating by the hot air of the dryer. Therefore, the gap filling layer 3 can be easily peeled off from the substrate 1.

In the present disclosure, each embodiment can be freely combined, and each embodiment can be appropriately modified or omitted.

Although the present disclosure has been described in detail, the above description is exemplary in all aspects and the disclosure is not limited thereto. It is understood that a myriad of variants not illustrated can be envisioned without departing from the scope of this disclosure.

1 substrate, 2 LED element part, 2A sealing resin, 2B blue LED, 2C pixel unit, 2E pixel unit, 2G green LED, 2R red LED, 3 gap filling layer, 3A high concentration gap filling layer, 3B high concentration gap filling Layers, 4 surface protection substrates, 9 molds, 10 LED display panels, 11 LED display panels, 12 LED display panels, 12A LED display panels, 30 gap fillers, 31 heat-expandable fine particles, 31A heat-expandable capsules, 40 thin plates Transparent glass substrate, 41 optical adhesive film, 100 LED display device.

Claims

With the board
A plurality of LED element units mounted discretely and in a matrix on the substrate,
The gap filling layer provided between the plurality of LED element portions and
A surface protective substrate having light transmission and covering the gap filling layer and the plurality of LED element portions is provided.
The surface protection substrate includes the gap filling layer and an adhesive layer in contact with the plurality of LED element portions.
The adhesive force of the adhesive layer to the gap filling layer and the plurality of LED element portions is larger than the adhesive force between the gap filling layer and the plurality of LED element portions and the adhesive force between the gap filling layer and the substrate. , LED display panel.
It is formed between the plurality of LED element portions and the gap filling layer, and between the substrate and the gap filling layer exposed from between the plurality of LED element portions, and the adhesiveness of the gap filling layer is increased. The LED display panel according to claim 1, further comprising a reduced adhesion reducing layer.
The LED display panel according to claim 1 or 2, wherein the gap filling layer contains a resin slightly adhesive to the plurality of LED element portions and the substrate.
The gap filling layer contains a gap filling material and thermally expandable fine particles mixed in the gap filling material.
The LED display panel according to any one of claims 1 to 3, wherein the heat-expandable fine particles have a larger coefficient of thermal expansion than the gap filler.
The gap filler is an elastic resin and is used.
The heat-expandable fine particles are
The LED display panel according to claim 4, further comprising an outer shell and a heat-expandable capsule in which the inside of the outer shell is filled with gas.
The gap filling layer includes a high concentration gap filling layer in contact with the adhesive layer of the surface protection substrate.
The weight distribution ratio of the heat-expandable fine particles contained in the high-concentration gap-filled layer is higher than the weight distribution ratio of the heat-expandable fine particles contained in a region closer to the substrate than the high-concentration gap-filled layer. The LED display panel according to claim 4 or 5.
The gap-filled layer includes a high-concentration gap-filled layer in contact with the substrate.
The weight distribution ratio of the heat-expandable fine particles contained in the high-concentration gap-filled layer is higher than the weight distribution ratio of the heat-expandable fine particles contained in the region closer to the surface protection substrate than the high-concentration gap-filled layer. , The LED display panel according to claim 4 or 5.
The LED display panel according to any one of claims 1 to 7, wherein the gap filling layer is black.
With the board
A plurality of LED element units mounted discretely and in a matrix on the substrate,
The gap filling layer provided between the plurality of LED element portions and
A surface protective substrate having light transmission and covering the gap filling layer and the plurality of LED element portions is provided.
The surface protection substrate includes the gap filling layer and an adhesive layer in contact with the plurality of LED element portions.
An LED display panel is prepared in which the adhesive force of the adhesive layer is larger than the adhesive force between the gap filling layer and the plurality of LED element portions and the adhesive force between the gap filling layer and the substrate.
The surface protection substrate is peeled off from the plurality of LED element portions, and the surface protection substrate is peeled off from the plurality of LED element portions.
The gap filling layer is peeled off from the substrate and the plurality of LED element portions, and the gap filling layer is separated from the substrate and the plurality of LED element portions.
A method for manufacturing an LED display panel, which repairs at least a part of the LED element portions exposed by peeling off the gap filling layer.
The method for manufacturing an LED display panel according to claim 9, wherein the surface protection substrate and the gap filling layer are peeled off together.
Before peeling off the surface protection substrate and the gap filling layer, the LED display panel is heated to expand the gap filling layer.
The method for manufacturing an LED display panel according to claim 9 or 10, wherein the surface protection substrate and the gap filling layer are peeled off after the expansion of the gap filling layer.
With the board
A plurality of LED element units mounted discretely and in a matrix on the substrate,
A gap filling layer provided between the plurality of LED element portions and whose volume expands more than that of the plurality of LED element portions by heating from the outside is provided.
The gap filling layer contains a gap filling material and thermally expandable fine particles mixed in the gap filling material.
The LED display panel in which the heat-expandable fine particles have a larger coefficient of thermal expansion than the gap filler.
The gap filler is an elastic resin and is used.
The heat-expandable fine particles are
The LED display panel according to claim 12, further comprising an outer shell and a heat-expandable capsule in which the inside of the outer shell is filled with gas.